'02 6 spd dyno runs
12-07-2001, 07:56 AM
#41
Not DAVEB the parts guy
Join Date: Aug 2000
Posts: 8,555
I think there are quite a few people that don't understand how dynos work and how HP is determined. HP is derived from torque. HP isn't "measured" on a dyno, it is calculated from torque therefore the HP can't be off if the torque numbers are correct. Torque (if I remember correctly) is a measurement of force over time. A dyno is a very simple machine. You strap the car on, get in the correct gear (4th manual, 3rd auto), floor it and take it to a determined rpm (usually redline). The dyno computer times how long it takes to accelerate the drums from the second you go WOT until you hit your determined rpm and let off. From this, torque is determined at every specified rpm interval. Then from this torque interval, HP is calculated.
Paul's and Phatguy's dynos do seem to have some problems and I suggest going to another shop with a Dynojet since that's what most of us dyno on. According to Phatguy, his HP peaks were in the upper 5000 rpms (5800?) in his 2K1. I understand that the operator didn't take the rpms to full redline, BUT his 2k1 should not be showing peak hp in the upper 5000s.
The shop isn't correcting their numbers to SAE. It sounds like the operator doesn't even know what SAE is. Unless the dynoruns were made at an altitude of 5000' above sea level, I don't see how it's possible to have a "corrected" dyno of 20hp+.
Steve's 2k2 (in stock form) is making a ton of tq, but not much more hp than a correctly dynoed 2k1. To me this makes sense. The 2k2 has more displacement which makes more torque. The problem is the 2k2 doesn't rev near as high as the 2k1. Simply put, the higher the engine revs and continues to breath, the more HP you get. The 2k2 makes power to 5500-5600rpms where as the 2k1 makes power to 6300-6400. The 2k2 is just like a 4th gen in terms of power output and driveability.
Most importantly, according to Paul's 2k2 dyno there is ABSOLUTELY no point in revving out any higher than 6200rpms in any gear. It's also very clear that the 3.5 has a rev limiter at 6200rpms (anyone catch that?) According to his dyno, peak hp occurs at 5200rpms (oddly 300-400rpms lower than most 4th gen VQs). Power doesn't fall off quickly till about 6000. Doing some simple math and the fact that his power curves look just like my 96s (not the same numbers) it looks like the best shift rpms for the 1/4 mile in a 2k2 Maxima are:
1-2 6200
2-3 6000
3-4 5800
From this, it is apparent that DMBMaxima was indeed shifting at the right rpms to get his 14.3-14.4. I think Paul's dyno clearly shows that it's impossible to rev out any higher than 6300rpms because of the limiter. Even if you could, revving out any higher is pointless because there is NO power to be found and peak occurs at 5200rpms. These short and fat power curves also explain why the 2k2 Maxima gets relatively low ets with not extremely high trap speeds. The 2k2 Max has the capabilty to launch hard with all the torque available, but can't rev out as long because of the relatively low hp peak.
Dave
Paul's and Phatguy's dynos do seem to have some problems and I suggest going to another shop with a Dynojet since that's what most of us dyno on. According to Phatguy, his HP peaks were in the upper 5000 rpms (5800?) in his 2K1. I understand that the operator didn't take the rpms to full redline, BUT his 2k1 should not be showing peak hp in the upper 5000s.
The shop isn't correcting their numbers to SAE. It sounds like the operator doesn't even know what SAE is. Unless the dynoruns were made at an altitude of 5000' above sea level, I don't see how it's possible to have a "corrected" dyno of 20hp+.
Steve's 2k2 (in stock form) is making a ton of tq, but not much more hp than a correctly dynoed 2k1. To me this makes sense. The 2k2 has more displacement which makes more torque. The problem is the 2k2 doesn't rev near as high as the 2k1. Simply put, the higher the engine revs and continues to breath, the more HP you get. The 2k2 makes power to 5500-5600rpms where as the 2k1 makes power to 6300-6400. The 2k2 is just like a 4th gen in terms of power output and driveability.
Most importantly, according to Paul's 2k2 dyno there is ABSOLUTELY no point in revving out any higher than 6200rpms in any gear. It's also very clear that the 3.5 has a rev limiter at 6200rpms (anyone catch that?) According to his dyno, peak hp occurs at 5200rpms (oddly 300-400rpms lower than most 4th gen VQs). Power doesn't fall off quickly till about 6000. Doing some simple math and the fact that his power curves look just like my 96s (not the same numbers) it looks like the best shift rpms for the 1/4 mile in a 2k2 Maxima are:
1-2 6200
2-3 6000
3-4 5800
From this, it is apparent that DMBMaxima was indeed shifting at the right rpms to get his 14.3-14.4. I think Paul's dyno clearly shows that it's impossible to rev out any higher than 6300rpms because of the limiter. Even if you could, revving out any higher is pointless because there is NO power to be found and peak occurs at 5200rpms. These short and fat power curves also explain why the 2k2 Maxima gets relatively low ets with not extremely high trap speeds. The 2k2 Max has the capabilty to launch hard with all the torque available, but can't rev out as long because of the relatively low hp peak.
Dave
12-07-2001, 08:12 AM
#42
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Well the rev limiter is not at 6200 on Paul's car nor mine. That is where the dyno cuts off. There is something screwy with the way this dyno is reading our HP and RPM. Does Steve have a dyno for his 6spd he can share?
The dyno guy will give us some more free runs but we need to figure out the problem first. With a stock 6spd dyno with peak HP/TQ rpm as well as some more 5spd y-pipe/intake dynos we might be able to figure out the problem. Can someone hook this up??
Right now it looks the RPM is off by 400-500 on our dynos but need some exisiting dynos to confirm. In other words the numbers Rick posted might not be to the correct RPM let alone the HP numbers in general.
The dyno guy will give us some more free runs but we need to figure out the problem first. With a stock 6spd dyno with peak HP/TQ rpm as well as some more 5spd y-pipe/intake dynos we might be able to figure out the problem. Can someone hook this up??
Right now it looks the RPM is off by 400-500 on our dynos but need some exisiting dynos to confirm. In other words the numbers Rick posted might not be to the correct RPM let alone the HP numbers in general.
12-07-2001, 08:29 AM
#43
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Thread Starter
Join Date: Sep 2001
Posts: 129
Originally posted by Dave B
I suggest going to another shop with a Dynojet since that's what most of us dyno on.
The shop isn't correcting their numbers to SAE.
Most importantly, according to Paul's 2k2 dyno there is ABSOLUTELY no point in revving out any higher than 6200rpms in any gear. It's also very clear that the 3.5 has a rev limiter at 6200rpms (anyone catch that?) According to his dyno, peak hp occurs at 5200rpms (oddly 300-400rpms lower than most 4th gen VQs). Power doesn't fall off quickly till about 6000.
Dave
I suggest going to another shop with a Dynojet since that's what most of us dyno on.
The shop isn't correcting their numbers to SAE.
Most importantly, according to Paul's 2k2 dyno there is ABSOLUTELY no point in revving out any higher than 6200rpms in any gear. It's also very clear that the 3.5 has a rev limiter at 6200rpms (anyone catch that?) According to his dyno, peak hp occurs at 5200rpms (oddly 300-400rpms lower than most 4th gen VQs). Power doesn't fall off quickly till about 6000.
Dave
I think all your discussion about rpm and shift points has some flaws. You seem to be assuming our dyno RPM numbers are correct. As well, when I'm driving the car I tend to shift using the tach in front of me which is providing completely different RPM information than what the dyno did. So even if the dyno RPM numbers are correct (which I very much doubt) they don't help anybody who's driving the car without access to those particular readouts.
I think I said this before - why would Nissan under estimate by 800 the RPM at which peak HP is made??? Also why is Phatguy's car suddenly making power at way lower RPM than expected or is normally experienced??? I think it's because the dyno rpm is screwed up and this incorrect number is being used to calculate HP. So maybe it is possible to have correct torque readings but then screw up the HP readings by calculating it with erroneous RPM input???
12-07-2001, 08:33 AM
#44
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Paul D is totally correct! Do not use those current numbers to determine shift points on a 2K2 6spd as of yet. Also take into consideration those numbers are for a modded 6spd.
I will go to a dynojet in Montreal if there is one? Anyone who knows of a good Dyno shop in Montreal please let me know?
Canadian guys check this out:
http://www.dynojet.com/maps/autodynos/canada.htm
Which one of these shops would be closest to Ottawa?
I will go to a dynojet in Montreal if there is one? Anyone who knows of a good Dyno shop in Montreal please let me know?
Canadian guys check this out:
http://www.dynojet.com/maps/autodynos/canada.htm
Which one of these shops would be closest to Ottawa?
12-07-2001, 09:06 AM
#45
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Btw Paul you never mentioned to these guys you are rolling on 18x8 Konig black opal Verdicts with 245/40 Kumhos (not used on the dyno btw). Both Rick and Paul know their stuff so expect to see some pHaT rides from these guys as soon as mods are available.
12-07-2001, 09:16 AM
#46
Not DAVEB the parts guy
Join Date: Aug 2000
Posts: 8,555
The rpms according to the dyno should be exactly right since the dyno reads voltage off of coil #1. If the operator hooks up the lead to the wrong coil, the idle rpm will be wildly off on the computer and they should realize before running the car. The numbers generated would also be wildly off.
The tachometer is probably off depending on gear and throttle position. Some tachs read too high and some read too low. I've got a shiftlight in my 4th gen which is set to go off at 6000rpms. Since 1st winds out so quickly, the light isn't triggered until the rpms hit close to 6300. Redline on the car is set at 6550 according to Nissan and verified my dyno. The reason the tach is reading 300rpms too high is most likely because the tach wire can't keep up with the engine in 1st. I've played around with my shiftlight and it appears the tach starts reading too high when the rpms hit 5000+ in 1st. In 2nd gear the tach seems to be about 100-200rpms off and in 3rd it's pretty much right on the money.
I'm pretty certain that those rpms on your dyno printout are correct. The peak hp an tq are also very close to Nissan's peak hp and tq rpms, especially the torque peak. It looks like the factory tach is off which is no surprise. I suggest getting a shiftlight or watching the tach as the operator dynos to see how far they are off.
Be honest guys, at what rpm does the 2k2 feel like it runs out of breath in 2nd. Does it really feel like it's still accelerating after an indicated 6000? Be honest.
I forgot to add that back to back dyno runs can also be off simply because of heat soak and other factors. Sometimes a motor just runs better compared to another run. I've seen 3-4fwhp and 4-5fwtq difference between runs made with the same mods within 15 minutes.
Dave
The tachometer is probably off depending on gear and throttle position. Some tachs read too high and some read too low. I've got a shiftlight in my 4th gen which is set to go off at 6000rpms. Since 1st winds out so quickly, the light isn't triggered until the rpms hit close to 6300. Redline on the car is set at 6550 according to Nissan and verified my dyno. The reason the tach is reading 300rpms too high is most likely because the tach wire can't keep up with the engine in 1st. I've played around with my shiftlight and it appears the tach starts reading too high when the rpms hit 5000+ in 1st. In 2nd gear the tach seems to be about 100-200rpms off and in 3rd it's pretty much right on the money.
I'm pretty certain that those rpms on your dyno printout are correct. The peak hp an tq are also very close to Nissan's peak hp and tq rpms, especially the torque peak. It looks like the factory tach is off which is no surprise. I suggest getting a shiftlight or watching the tach as the operator dynos to see how far they are off.
Be honest guys, at what rpm does the 2k2 feel like it runs out of breath in 2nd. Does it really feel like it's still accelerating after an indicated 6000? Be honest.
I forgot to add that back to back dyno runs can also be off simply because of heat soak and other factors. Sometimes a motor just runs better compared to another run. I've seen 3-4fwhp and 4-5fwtq difference between runs made with the same mods within 15 minutes.
Dave
12-07-2001, 09:17 AM
#47
Dyno plot says I have the most area under the Administrator curve
Join Date: Jul 2001
Posts: 7,060
Shift Points
I modified the 2000 SE 5spd Maxima in CarTest2000 to be a 2002 SE 6spd. Threw in the VQ35DE and the 6spd ratios that I had previously and here's what it gives as far as shift points:
1-2: 6600rpm
2-3: 6520rpm
3-4: 6380rpm
4-5: 6330rpm
Power drops off before redline on the VQ35, but not to the point where you'd want to shift as early as 5800rpm, IMHO.
BTW, for performance figures it gave:
0-60mph: 5.93s
1/4 mile: 14.66 @ 97.36mph
I suspect that CarTest2k might be a little pessimistic on the power drop off after 5800rpm since dmb was able to get a 14.3. I also tried adjusting temperature and humidity but that didn't seem to effect it very much. I didn't play with "shift time" though. Maybe dmb was able to shift very quickly. Who knows...
It did give a 97mph trap speed, though, and it beat the Alty's 6.28s 0-60mph time, at least in the simulation
1-2: 6600rpm
2-3: 6520rpm
3-4: 6380rpm
4-5: 6330rpm
Power drops off before redline on the VQ35, but not to the point where you'd want to shift as early as 5800rpm, IMHO.
BTW, for performance figures it gave:
0-60mph: 5.93s
1/4 mile: 14.66 @ 97.36mph
I suspect that CarTest2k might be a little pessimistic on the power drop off after 5800rpm since dmb was able to get a 14.3. I also tried adjusting temperature and humidity but that didn't seem to effect it very much. I didn't play with "shift time" though. Maybe dmb was able to shift very quickly. Who knows...
It did give a 97mph trap speed, though, and it beat the Alty's 6.28s 0-60mph time, at least in the simulation
12-07-2001, 09:43 AM
#48
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I put the dyno numbers in Excel, but unfortunately I can't attach it here. If you guys want it, I'll email it to you. Anyway...
It appears that the intake on the 2002 switches at a low 3750 rpm. That's almost 1500 rpm lower than the 3.0L 2000/2001 motors. Either the low-rpm tuning of the intake manifold is designed to give more low end punch or just the geometry of the 3.5L is such that the motor develops peak torque at a lower rpm. My guess is #2 (motor just peaks lower). Nissan basically bored out and stroked the 3.0L motor so there's no way the engine characteristics (peak torque rpm, revability, etc) won't change also. It appears it has.
Either that or the cams in the 3.5L motor are really really mild. Maybe that's why Nissan is claiming 280HP+ out of the same motor tuned for the upcoming 350Z...more aggressive cams.
Damn, this engine has buttloads of low end torque, doesn't it? Makes 192 ftlbs at 1300, that's 85% of max at only 1300! Probably makes 80% of max at only 1000 or so. Like a freaking truck motor. Jeezus.
It appears that the intake on the 2002 switches at a low 3750 rpm. That's almost 1500 rpm lower than the 3.0L 2000/2001 motors. Either the low-rpm tuning of the intake manifold is designed to give more low end punch or just the geometry of the 3.5L is such that the motor develops peak torque at a lower rpm. My guess is #2 (motor just peaks lower). Nissan basically bored out and stroked the 3.0L motor so there's no way the engine characteristics (peak torque rpm, revability, etc) won't change also. It appears it has.
Either that or the cams in the 3.5L motor are really really mild. Maybe that's why Nissan is claiming 280HP+ out of the same motor tuned for the upcoming 350Z...more aggressive cams.
Damn, this engine has buttloads of low end torque, doesn't it? Makes 192 ftlbs at 1300, that's 85% of max at only 1300! Probably makes 80% of max at only 1000 or so. Like a freaking truck motor. Jeezus.
12-07-2001, 09:55 AM
#49
Dyno plot says I have the most area under the Administrator curve
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Posts: 7,060
Intake Manifold / Tuning Theory
Originally posted by Keven97SE
It appears that the intake on the 2002 switches at a low 3750 rpm. That's almost 1500 rpm lower than the 3.0L 2000/2001 motors.
It appears that the intake on the 2002 switches at a low 3750 rpm. That's almost 1500 rpm lower than the 3.0L 2000/2001 motors.
If the VQ30 secondaries opened up at 5000rpm before, then...
The VQ35 with the same intake might need to open up the secondary runners at 3750rpm to maintain the power curve if no intake work besides changing the x-over point was done, which is what I'm believing.
The secondaries on the VQ30DE were able to maintain power all the way up to redline. But with the added displacement, if Nissan didn't increase the capacity then the intake manifold would become a bottleneck sooner, and hence the earlier 5800rpm peak power point and the power drop off after 5800rpm.
I believe that Nissan didn't change the intake manifold between the VQ30 and the VQ35 engines, but just tuned the x-over point to keep a smooth power curve. This could explain why the VQ35 power falls off much earlier.
To get additional power in the Z, all Nissan would have to do is increase the capacity of the intake manifold to get 280HP or so.
If this is the case, then maybe you guys would be able to do a Z intake manifold swap?
12-07-2001, 10:03 AM
#50
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Originally posted by Keven97SE
I put the dyno numbers in Excel, but unfortunately I can't attach it here. If you guys want it, I'll email it to you. Anyway...
I put the dyno numbers in Excel, but unfortunately I can't attach it here. If you guys want it, I'll email it to you. Anyway...
Please let me know your year, tranny, and mods done on the car.
If you can include the graph and numbers that would be awesome!
12-07-2001, 10:06 AM
#51
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Re: Intake Manifold / Tuning Theory
No, the intake manifold is totally different from the 3L. It's not composite, looks to have dual butterfly throttle body (two pipes routed to plenum). It's aluminum again, not composite. It's totally different. Not to say that Nissan maybe didn't increase the flow capacity, but I kinda doubt that they would have redesigned it to the old engine specs.
I think I'm on board with the other guys here that think the rpms are off. That explains a lot. Explains why peak HP is 800 rpm lower than Nissan specifies, explains why the rpms stop at 61/6200 (should be 65/6600). Explains why there's so much freaking torque at low rpms. Explains why the crossover point of the intake manifold dropped so much from the 3L. Just a rough calculation that assumes the intake manifold geometry DID stay the same, a 3.5/3.0 increase in air flow would result in a 3.0/3.5 drop in crossover point, ie 5100*3.0/3.5, or 4400 rpm. I can see the crossover point dropping to that range, but not 3750. That's a huge drop.
My guess? Rpms are 500 too low. Everything's low by 500. Look at where torque first surges up, 1300 rpm vs 1800 rpm on the old motor. It's just too low.
But that's just my guess.
I think I'm on board with the other guys here that think the rpms are off. That explains a lot. Explains why peak HP is 800 rpm lower than Nissan specifies, explains why the rpms stop at 61/6200 (should be 65/6600). Explains why there's so much freaking torque at low rpms. Explains why the crossover point of the intake manifold dropped so much from the 3L. Just a rough calculation that assumes the intake manifold geometry DID stay the same, a 3.5/3.0 increase in air flow would result in a 3.0/3.5 drop in crossover point, ie 5100*3.0/3.5, or 4400 rpm. I can see the crossover point dropping to that range, but not 3750. That's a huge drop.
My guess? Rpms are 500 too low. Everything's low by 500. Look at where torque first surges up, 1300 rpm vs 1800 rpm on the old motor. It's just too low.
But that's just my guess.
Originally posted by SteVTEC
I believe that Nissan didn't change the intake manifold between the VQ30 and the VQ35 engines, but just tuned the x-over point to keep a smooth power curve. This could explain why the VQ35 power falls off much earlier.
I believe that Nissan didn't change the intake manifold between the VQ30 and the VQ35 engines, but just tuned the x-over point to keep a smooth power curve. This could explain why the VQ35 power falls off much earlier.
12-07-2001, 10:10 AM
#52
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Sorry, I meant I put Paul D.'s dyno numbers into Excel. I just have a lowly 190HP-at-the-wheels 3000 lb 5speed 4th gen. 
Originally posted by PhatGuy
Cool! Please email it to me at phat@sympatico.ca
Please let me know your year, tranny, and mods done on the car.
If you can include the graph and numbers that would be awesome!
Cool! Please email it to me at phat@sympatico.ca
Please let me know your year, tranny, and mods done on the car.
If you can include the graph and numbers that would be awesome!
12-07-2001, 10:21 AM
#54
Dyno plot says I have the most area under the Administrator curve
Join Date: Jul 2001
Posts: 7,060
Re: Re: Intake Manifold / Tuning Theory
Originally posted by Keven97SE
No, the intake manifold is totally different from the 3L. It's not composite, looks to have dual butterfly throttle body (two pipes routed to plenum).
No, the intake manifold is totally different from the 3L. It's not composite, looks to have dual butterfly throttle body (two pipes routed to plenum).
12-07-2001, 10:23 AM
#55
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Join Date: Sep 2001
Posts: 129
Originally posted by Dave B
The rpms according to the dyno should be exactly right since the dyno reads voltage off of coil #1. I'm pretty certain that those rpms on your dyno printout are correct. The peak hp an tq are also very close to Nissan's peak hp and tq rpms, especially the torque peak.
Does it really feel like it's still accelerating after an indicated 6000? Be honest.
Dave
The rpms according to the dyno should be exactly right since the dyno reads voltage off of coil #1. I'm pretty certain that those rpms on your dyno printout are correct. The peak hp an tq are also very close to Nissan's peak hp and tq rpms, especially the torque peak.
Does it really feel like it's still accelerating after an indicated 6000? Be honest.
Dave
As for the Mustang dyno's peak torque rpm being fairly close, the stock dyno run showed peak at 4,000 whereas Nissan says peak torque is at 4,400. Although that's 'only' 10% and the peak HP rpm seems to be off by ~15%, it's still not very close in my books.
As for whether the '02 6 spd. feels like it's still accelerating past a tach indicated 6,000 rpm in 2nd gear, there AIN'T no doubt in my mind that it IS - 6,500 comes up fast enough that you have to be VERY ready with the shifter or you're gunna hit the fuel cut-off. As Phatguy mentioned, when you get into 3rd. there isn't just a squak, it actually lays rubber.
12-07-2001, 10:27 AM
#56
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I think the 3.5L motors use continuously variable cam timing, at least I thought. It's not like the 3rd gens that just snap the cams into a different phase, so you should see a jump in the torque curve, just a lengthening of the plateau. Any jumps in the curve should be due to the intake manfifold only (ie 3750 rpm).
But then again I'm not totally up to speed on the new motor's technology so I can't say this with much confidence.
On another note, how'r ya doing, Jeff? Long time no speak.
But then again I'm not totally up to speed on the new motor's technology so I can't say this with much confidence.
On another note, how'r ya doing, Jeff? Long time no speak.
Originally posted by Jeff92se
Don't you guys have to consider at what rpm/load the 3.5VQ's VTC assemblies are kicking in? That would show as a bump in the hp/torque curves also. Just a guess
Don't you guys have to consider at what rpm/load the 3.5VQ's VTC assemblies are kicking in? That would show as a bump in the hp/torque curves also. Just a guess
12-07-2001, 10:31 AM
#57
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Which coil is 1?
Originally posted by Dave B
The rpms according to the dyno should be exactly right since the dyno reads voltage off of coil #1. If the operator hooks up the lead to the wrong coil, the idle rpm will be wildly off on the computer and they should realize before running the car. The numbers generated would also be wildly off.
The tachometer is probably off depending on gear and throttle position. Some tachs read too high and some read too low. I've got a shiftlight in my 4th gen which is set to go off at 6000rpms. Since 1st winds out so quickly, the light isn't triggered until the rpms hit close to 6300. Redline on the car is set at 6550 according to Nissan and verified my dyno. The reason the tach is reading 300rpms too high is most likely because the tach wire can't keep up with the engine in 1st. I've played around with my shiftlight and it appears the tach starts reading too high when the rpms hit 5000+ in 1st. In 2nd gear the tach seems to be about 100-200rpms off and in 3rd it's pretty much right on the money.
I'm pretty certain that those rpms on your dyno printout are correct. The peak hp an tq are also very close to Nissan's peak hp and tq rpms, especially the torque peak. It looks like the factory tach is off which is no surprise. I suggest getting a shiftlight or watching the tach as the operator dynos to see how far they are off.
Be honest guys, at what rpm does the 2k2 feel like it runs out of breath in 2nd. Does it really feel like it's still accelerating after an indicated 6000? Be honest.
I forgot to add that back to back dyno runs can also be off simply because of heat soak and other factors. Sometimes a motor just runs better compared to another run. I've seen 3-4fwhp and 4-5fwtq difference between runs made with the same mods within 15 minutes.
Dave
The rpms according to the dyno should be exactly right since the dyno reads voltage off of coil #1. If the operator hooks up the lead to the wrong coil, the idle rpm will be wildly off on the computer and they should realize before running the car. The numbers generated would also be wildly off.
The tachometer is probably off depending on gear and throttle position. Some tachs read too high and some read too low. I've got a shiftlight in my 4th gen which is set to go off at 6000rpms. Since 1st winds out so quickly, the light isn't triggered until the rpms hit close to 6300. Redline on the car is set at 6550 according to Nissan and verified my dyno. The reason the tach is reading 300rpms too high is most likely because the tach wire can't keep up with the engine in 1st. I've played around with my shiftlight and it appears the tach starts reading too high when the rpms hit 5000+ in 1st. In 2nd gear the tach seems to be about 100-200rpms off and in 3rd it's pretty much right on the money.
I'm pretty certain that those rpms on your dyno printout are correct. The peak hp an tq are also very close to Nissan's peak hp and tq rpms, especially the torque peak. It looks like the factory tach is off which is no surprise. I suggest getting a shiftlight or watching the tach as the operator dynos to see how far they are off.
Be honest guys, at what rpm does the 2k2 feel like it runs out of breath in 2nd. Does it really feel like it's still accelerating after an indicated 6000? Be honest.
I forgot to add that back to back dyno runs can also be off simply because of heat soak and other factors. Sometimes a motor just runs better compared to another run. I've seen 3-4fwhp and 4-5fwtq difference between runs made with the same mods within 15 minutes.
Dave
12-07-2001, 10:34 AM
#58
Dyno plot says I have the most area under the Administrator curve
Join Date: Jul 2001
Posts: 7,060
Originally posted by Jeff92se
Don't you guys have to consider at what rpm/load the 3.5VQ's VTC assemblies are kicking in? That would show as a bump in the hp/torque curves also. Just a guess
Don't you guys have to consider at what rpm/load the 3.5VQ's VTC assemblies are kicking in? That would show as a bump in the hp/torque curves also. Just a guess
The VTC on the Maxima doesn't vary valve lift or duration so it doesn't switch cam profiles or anything, at least to my knowledge. It just varies the cam phasing to open the valves (with fixed duration and lift) earlier (at high rpm's) and later (at low rpm's) to optimize combustion efficiency. Toyota's VVT-i system is very similar.
So VTC will adjust cam phasing continuously, but if for some reason it isn't working properly then that could potentially cause a loss of some power at the top-end.
12-07-2001, 10:39 AM
#59
Yes Steve I know how VTCs work. I have them on my VE 3-gen and have worked on them before. I didn't know that the new VQs VTC were continousouly varible though. That's news to me but makes perfect sense since all other makers have the same thing also. Mine are not continuously varible. There is a set rpm/load that it. It's either off or on.
Did you know Nissan actually has VTEC type tech on their Japanese/Europe only engines? Porsche has both and uses a more simple system to boot.
Did you know Nissan actually has VTEC type tech on their Japanese/Europe only engines? Porsche has both and uses a more simple system to boot.
Originally posted by SteVTEC
The original brochure called VTC "CVTCS" (Continuously Variable Timing Control System). I guess they figured that was a little too much to swallow and just shortened it to VTC (Variable Timing Control)
The VTC on the Maxima doesn't vary valve lift or duration so it doesn't switch cam profiles or anything, at least to my knowledge. It just varies the cam phasing to open the valves (with fixed duration and lift) earlier (at high rpm's) and later (at low rpm's) to optimize combustion efficiency. Toyota's VVT-i system is very similar.
So VTC will adjust cam phasing continuously, but if for some reason it isn't working properly then that could potentially cause a loss of some power at the top-end.
The original brochure called VTC "CVTCS" (Continuously Variable Timing Control System). I guess they figured that was a little too much to swallow and just shortened it to VTC (Variable Timing Control)
The VTC on the Maxima doesn't vary valve lift or duration so it doesn't switch cam profiles or anything, at least to my knowledge. It just varies the cam phasing to open the valves (with fixed duration and lift) earlier (at high rpm's) and later (at low rpm's) to optimize combustion efficiency. Toyota's VVT-i system is very similar.
So VTC will adjust cam phasing continuously, but if for some reason it isn't working properly then that could potentially cause a loss of some power at the top-end.
12-07-2001, 10:56 AM
#62
Dyno plot says I have the most area under the Administrator curve
Join Date: Jul 2001
Posts: 7,060
Originally posted by Jeff92se
I have them on my VE 3-gen and have worked on them before...Mine are not continuously varible. There is a set rpm/load that it. It's either off or on.
I have them on my VE 3-gen and have worked on them before...Mine are not continuously varible. There is a set rpm/load that it. It's either off or on.
12-07-2001, 05:10 PM
#64
Senior Member
Join Date: Sep 2001
Location: Detroit Metro Area
Posts: 1,617
Re: Detailed Dyno Results for 2002 6 spd
Originally posted by Rick Sudac
For those of you interested, here are the results that Paul D. and Phatboy^^ were talking about re the Mustang dyno yesterday. I havent had time to look at them myself but you will see where the HP numbers are suspect. Sorry I couldn<t figure out how to do an attachment so I just pasted in the info. Again, this is a 2002 6 speed with 1700KM or about 1000 miles on it with a Stillen air intake and muffler.
For those of you interested, here are the results that Paul D. and Phatboy^^ were talking about re the Mustang dyno yesterday. I havent had time to look at them myself but you will see where the HP numbers are suspect. Sorry I couldn<t figure out how to do an attachment so I just pasted in the info. Again, this is a 2002 6 speed with 1700KM or about 1000 miles on it with a Stillen air intake and muffler.
Stereodude
12-07-2001, 05:38 PM
#65
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Join Date: Sep 2001
Location: Detroit Metro Area
Posts: 1,617
Re: Re: Intake Manifold / Tuning Theory
Originally posted by Keven97SE
My guess? Rpms are 500 too low. Everything's low by 500. Look at where torque first surges up, 1300 rpm vs 1800 rpm on the old motor. It's just too low.
But that's just my guess.
My guess? Rpms are 500 too low. Everything's low by 500. Look at where torque first surges up, 1300 rpm vs 1800 rpm on the old motor. It's just too low.
But that's just my guess.
1800 76.63 26.26313785
1900 153.26 55.44440213
2000 191.63 72.9741051
2100 191.76 76.67479056
2200 191.88 80.37623762
2300 194.62 85.22962681
2400 197.36 90.1873572
2500 199.05 94.74961919
2600 199.69 98.85643564
2700 200.33 102.9876238
2800 202.17 107.7829398
2900 204.01 112.6483244
3000 207.59 118.5776847
3100 212.91 125.6704113
3200 218.23 132.9657273
3300 220.25 138.3901371
3400 222.27 143.8914699
3500 223.22 148.7566641
3600 223.09 152.9177456
3700 222.97 157.0809216
3800 224.49 162.4261234
3900 226.02 167.8366337
4000 225.59 171.8126428
4100 223.21 174.25
4200 220.83 176.5967251
4300 218.72 179.0738766
4400 216.61 181.4706778
4500 217.39 186.2633283
4600 221.06 193.6169078
4700 224.73 201.1102437
4800 224.45 205.1332826
4900 224.18 209.1549886
5000 223.48 212.7570449
5100 222.37 215.9343107
5200 221.25 219.0594059
5300 218.9 220.9006093
5400 216.54 222.6420411
5500 213.84 223.9375476
5600 210.78 224.7463823
5700 207.73 225.449543
5800 203.98 225.2635187
5900 200.23 224.9346915
6000 196.06 223.9832445
6100 191.48 222.3968012
6200 186.89 220.6241432
6300 181.76 218.0289414
6400 176.63 215.2383854
6500 171.9 212.7475248
6600 167.57 210.5792079
6700 163.23 208.2332445
6800 160.54 207.8583397
6900 157.85 207.3809977
7000 125.2 166.8697639
It makes sense too if you think about it. They really only measure torque on the dyno and they multiply by the RPM. If the RPM is low the HP is going to be low. If he took the car to the redline, but yet the dyno only shows 6200 RPM. We know the fuel cutoff is at 7k. Lets assume that the last data point it hit the fuel cutoff. So that puts us 700RPM off. After hearing how the dyno is configured it doesn't seem that far fetched that it could be off by 700RPM. Post correction both the HP and torque appear a lot better. I believe these numbers are pretty much correct.
Stereodude
12-10-2001, 06:09 AM
#66
Senior Member
Thread Starter
Join Date: Sep 2001
Posts: 129
Re: Re: Re: Intake Manifold / Tuning Theory
Originally posted by Stereodude
I'd guess 700 low. That's how you explain it. If you look at the numbers the torque looks high for the RPM and the HP is low. If we do a little "correction" by 700RPM you get the following numbers.
1800 76.63 26.26313785
1900 153.26 55.44440213
2000 191.63 72.9741051
2100 191.76 76.67479056
2200 191.88 80.37623762
2300 194.62 85.22962681
2400 197.36 90.1873572
2500 199.05 94.74961919
2600 199.69 98.85643564
2700 200.33 102.9876238
2800 202.17 107.7829398
2900 204.01 112.6483244
3000 207.59 118.5776847
3100 212.91 125.6704113
3200 218.23 132.9657273
3300 220.25 138.3901371
3400 222.27 143.8914699
3500 223.22 148.7566641
3600 223.09 152.9177456
3700 222.97 157.0809216
3800 224.49 162.4261234
3900 226.02 167.8366337
4000 225.59 171.8126428
4100 223.21 174.25
4200 220.83 176.5967251
4300 218.72 179.0738766
4400 216.61 181.4706778
4500 217.39 186.2633283
4600 221.06 193.6169078
4700 224.73 201.1102437
4800 224.45 205.1332826
4900 224.18 209.1549886
5000 223.48 212.7570449
5100 222.37 215.9343107
5200 221.25 219.0594059
5300 218.9 220.9006093
5400 216.54 222.6420411
5500 213.84 223.9375476
5600 210.78 224.7463823
5700 207.73 225.449543
5800 203.98 225.2635187
5900 200.23 224.9346915
6000 196.06 223.9832445
6100 191.48 222.3968012
6200 186.89 220.6241432
6300 181.76 218.0289414
6400 176.63 215.2383854
6500 171.9 212.7475248
6600 167.57 210.5792079
6700 163.23 208.2332445
6800 160.54 207.8583397
6900 157.85 207.3809977
7000 125.2 166.8697639
It makes sense too if you think about it. They really only measure torque on the dyno and they multiply by the RPM. If the RPM is low the HP is going to be low. If he took the car to the redline, but yet the dyno only shows 6200 RPM. We know the fuel cutoff is at 7k. Lets assume that the last data point it hit the fuel cutoff. So that puts us 700RPM off. After hearing how the dyno is configured it doesn't seem that far fetched that it could be off by 700RPM. Post correction both the HP and torque appear a lot better. I believe these numbers are pretty much correct.
Stereodude
I'd guess 700 low. That's how you explain it. If you look at the numbers the torque looks high for the RPM and the HP is low. If we do a little "correction" by 700RPM you get the following numbers.
1800 76.63 26.26313785
1900 153.26 55.44440213
2000 191.63 72.9741051
2100 191.76 76.67479056
2200 191.88 80.37623762
2300 194.62 85.22962681
2400 197.36 90.1873572
2500 199.05 94.74961919
2600 199.69 98.85643564
2700 200.33 102.9876238
2800 202.17 107.7829398
2900 204.01 112.6483244
3000 207.59 118.5776847
3100 212.91 125.6704113
3200 218.23 132.9657273
3300 220.25 138.3901371
3400 222.27 143.8914699
3500 223.22 148.7566641
3600 223.09 152.9177456
3700 222.97 157.0809216
3800 224.49 162.4261234
3900 226.02 167.8366337
4000 225.59 171.8126428
4100 223.21 174.25
4200 220.83 176.5967251
4300 218.72 179.0738766
4400 216.61 181.4706778
4500 217.39 186.2633283
4600 221.06 193.6169078
4700 224.73 201.1102437
4800 224.45 205.1332826
4900 224.18 209.1549886
5000 223.48 212.7570449
5100 222.37 215.9343107
5200 221.25 219.0594059
5300 218.9 220.9006093
5400 216.54 222.6420411
5500 213.84 223.9375476
5600 210.78 224.7463823
5700 207.73 225.449543
5800 203.98 225.2635187
5900 200.23 224.9346915
6000 196.06 223.9832445
6100 191.48 222.3968012
6200 186.89 220.6241432
6300 181.76 218.0289414
6400 176.63 215.2383854
6500 171.9 212.7475248
6600 167.57 210.5792079
6700 163.23 208.2332445
6800 160.54 207.8583397
6900 157.85 207.3809977
7000 125.2 166.8697639
It makes sense too if you think about it. They really only measure torque on the dyno and they multiply by the RPM. If the RPM is low the HP is going to be low. If he took the car to the redline, but yet the dyno only shows 6200 RPM. We know the fuel cutoff is at 7k. Lets assume that the last data point it hit the fuel cutoff. So that puts us 700RPM off. After hearing how the dyno is configured it doesn't seem that far fetched that it could be off by 700RPM. Post correction both the HP and torque appear a lot better. I believe these numbers are pretty much correct.
Stereodude
Interesting calculations which certainly seem to make more sense than what the dyno sheet is saying.
The next time at the dyno I figure we should try to trick it by doing the 3,000 rpm calibration when the car's tach is only reading around 2,300-2,400. Thing is I'm not going back until I have another modification to test (either a Y-pipe or the UDP, neither of which seem to be available yet). Maybe Phatguy will want to try his car again with a different dyno calibration.
12-10-2001, 07:16 AM
#67
I don't know if it counts given my dyno was incorrectly done (non SAE, in 2nd gear) here but i can surely say that your rpm is off by at least a few hundreds.
My 2k2 Auto in 2nd gear tops off at 6500 rpm before it shuts off. I also noticed my tach was off by a few hundreds. Looking at it off-center i saw the tach go to 6900-7000 before it shut down.
My 2k2 Auto in 2nd gear tops off at 6500 rpm before it shuts off. I also noticed my tach was off by a few hundreds. Looking at it off-center i saw the tach go to 6900-7000 before it shut down.
12-10-2001, 07:20 AM
#68
Re: Video those runs, please!
Well, i can tell you. In stock form it really isn't rumbling by any means (e.g. sweet low rumble).
I actually got annoyed by the sound... didn't sound very masculine for a car of this caliber.
But then again, it performs
I actually got annoyed by the sound... didn't sound very masculine for a car of this caliber.
But then again, it performs
Originally posted by IceY2K1
It would be SWEET if you guys could video your dyno runs. I'd like to hear what a 2K2 sounds like in 3rd gear at WOT.
It would be SWEET if you guys could video your dyno runs. I'd like to hear what a 2K2 sounds like in 3rd gear at WOT.
12-10-2001, 07:31 AM
#69
Not DAVEB the parts guy
Join Date: Aug 2000
Posts: 8,555
SoundMike-
Your hp is VERY odd looking. I've never seen anything like it and I almost wonder if it's a factor of the car being dynoed in 2nd. What's so odd about it is that the dyno is showing the 3.5 holds the same hp from 5400-6400rpms with no increase or decrease in power. I don't know how this is possible. At the very least, the power curve should continue to go up or start to drop off. Some motors are peakier than others where power climbs very fast or drops off very fast. Your hp almost looks like a VTEC Honda's torque curve. It's very strange to say the least. HP is directly related to torque and you orque curve looks just like my torque curve on my 3.0. Even the generated numbers and rpms are identical. However our HP curves are completely different. Mine climbs in a nice linear fashion, peaks at 5700rpms and then starts to fall off by 5hp every 200rpms. At 6300rpms, HP drops off like an anvil.
Dave
Your hp is VERY odd looking. I've never seen anything like it and I almost wonder if it's a factor of the car being dynoed in 2nd. What's so odd about it is that the dyno is showing the 3.5 holds the same hp from 5400-6400rpms with no increase or decrease in power. I don't know how this is possible. At the very least, the power curve should continue to go up or start to drop off. Some motors are peakier than others where power climbs very fast or drops off very fast. Your hp almost looks like a VTEC Honda's torque curve. It's very strange to say the least. HP is directly related to torque and you orque curve looks just like my torque curve on my 3.0. Even the generated numbers and rpms are identical. However our HP curves are completely different. Mine climbs in a nice linear fashion, peaks at 5700rpms and then starts to fall off by 5hp every 200rpms. At 6300rpms, HP drops off like an anvil.
Dave
12-10-2001, 07:36 AM
#70
Senior Member
Join Date: Sep 2001
Location: Detroit Metro Area
Posts: 1,617
Originally posted by Dave B
SoundMike-
Your hp is VERY odd looking. I've never seen anything like it and I almost wonder if it's a factor of the car being dynoed in 2nd. What's so odd about it is that the dyno is showing the 3.5 holds the same hp from 5400-6400rpms with no increase or decrease in power. I don't know how this is possible. At the very least, the power curve should continue to go up or start to drop off. Some motors are peakier than others where power climbs very fast or drops off very fast. Your hp almost looks like a VTEC Honda's torque curve. It's very strange to say the least. HP is directly related to torque and you orque curve looks just like my torque curve on my 3.0. Even the generated numbers and rpms are identical. However our HP curves are completely different. Mine climbs in a nice linear fashion, peaks at 5700rpms and then starts to fall off by 5hp every 200rpms. At 6300rpms, HP drops off like an anvil.
Dave
SoundMike-
Your hp is VERY odd looking. I've never seen anything like it and I almost wonder if it's a factor of the car being dynoed in 2nd. What's so odd about it is that the dyno is showing the 3.5 holds the same hp from 5400-6400rpms with no increase or decrease in power. I don't know how this is possible. At the very least, the power curve should continue to go up or start to drop off. Some motors are peakier than others where power climbs very fast or drops off very fast. Your hp almost looks like a VTEC Honda's torque curve. It's very strange to say the least. HP is directly related to torque and you orque curve looks just like my torque curve on my 3.0. Even the generated numbers and rpms are identical. However our HP curves are completely different. Mine climbs in a nice linear fashion, peaks at 5700rpms and then starts to fall off by 5hp every 200rpms. At 6300rpms, HP drops off like an anvil.
Dave
Stereodude
12-10-2001, 08:01 AM
#71
Dave, Stereodude... you're both right. It is very odd looking. Given it wasn't run in 3rd as it should normally have been done on an Auto nor was it SAE corrected there's nothing to be derived from this dyno run, unfortunately.
Except perhaps to know where the cut-off occurs (and for me to know that my tach is off)
Except perhaps to know where the cut-off occurs (and for me to know that my tach is off)
12-10-2001, 08:09 AM
#72
Senior Member
Join Date: Sep 2001
Location: Detroit Metro Area
Posts: 1,617
Originally posted by soundmike
Dave, Stereodude... you're both right. It is very odd looking. Given it wasn't run in 3rd as it should normally have been done on an Auto nor was it SAE corrected there's nothing to be derived from this dyno run, unfortunately.
Except perhaps to know where the cut-off occurs (and for me to know that my tach is off)
Dave, Stereodude... you're both right. It is very odd looking. Given it wasn't run in 3rd as it should normally have been done on an Auto nor was it SAE corrected there's nothing to be derived from this dyno run, unfortunately.
Except perhaps to know where the cut-off occurs (and for me to know that my tach is off)
Stereodude
12-10-2001, 08:14 AM
#73
I personally know mine is off by at least 500 rpm as that's how far the needle went up (7000 rpm) before it shut down.
Judging from the run, that correlates to approximately 6500 rpm. Should give me a good idea of when to shift manually whenever i do get to that track. <g>
Judging from the run, that correlates to approximately 6500 rpm. Should give me a good idea of when to shift manually whenever i do get to that track. <g>
Originally posted by Stereodude
I'm not all that certain that your tach is off that much. So far everyone seems to say that the car can get to about 7k RPM (per the tach). It's my understanding that not all tachs are going to be off the same amount (it varies from car to car). So it seems unlikely that everyone's tach is off the exact same amount.
Stereodude
I'm not all that certain that your tach is off that much. So far everyone seems to say that the car can get to about 7k RPM (per the tach). It's my understanding that not all tachs are going to be off the same amount (it varies from car to car). So it seems unlikely that everyone's tach is off the exact same amount.
Stereodude
12-10-2001, 08:25 AM
#74
Senior Member
Join Date: Sep 2001
Location: Detroit Metro Area
Posts: 1,617
Originally posted by soundmike
I personally know mine is off by at least 500 rpm as that's how far the needle went up (7000 rpm) before it shut down.
Judging from the run, that correlates to approximately 6500 rpm. Should give me a good idea of when to shift manually whenever i do get to that track. <g>
I personally know mine is off by at least 500 rpm as that's how far the needle went up (7000 rpm) before it shut down.
Judging from the run, that correlates to approximately 6500 rpm. Should give me a good idea of when to shift manually whenever i do get to that track. <g>
Stereodude
12-10-2001, 09:52 AM
#75
It did drop off to 0 after around 6600 rpm. However that's not shown on this graph. I do have another print out showing the entire graph from start to end (as it showed on the computer screen) and completing the graph itself. I didn't bother posting that one since i didn't think it contained that much more information compared to this one.
Originally posted by Stereodude
Maybe someone else can correct me if I'm wrong, but the last point on your graph seems to be at about 6600RPM. It's dropping off at that point, but it's not at 0. If they ran until you hit the limiter the last point on the curves should be at 0. When you hit the limiter you have 0 torque and 0 HP. Since your graph never makes it to 0 or never has any wild fluctuations at the very end I don't think you can make the conclusion that your RPM is off simply because your graph doesn't show where the limiter is.
Stereodude
Maybe someone else can correct me if I'm wrong, but the last point on your graph seems to be at about 6600RPM. It's dropping off at that point, but it's not at 0. If they ran until you hit the limiter the last point on the curves should be at 0. When you hit the limiter you have 0 torque and 0 HP. Since your graph never makes it to 0 or never has any wild fluctuations at the very end I don't think you can make the conclusion that your RPM is off simply because your graph doesn't show where the limiter is.
Stereodude
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