I can't speak for dave but ballpark is about $675 .. depends on so of the other parts you need.

$700 is a high number ... I spent less than $700 and bought about $30 extra worth of stuff

Again my cost.. not dave's

 

Dave - Was there a noticable difference in your 1/8 mile times?

Ian showed a gain of .4 seconds in the 1/4 and about .2 in the 1/8 in his auto before he aded his SC.

 

This whole thread has turned into a nightmare of dumbassedness. Makes me want to put my head through the wall...

If you don't understand the concept of how altitude (1100 feet) and temperature/humidity affect HP and acceleration times, please stop posting, because you're adding nothing to this post...I take that back, you are adding -XX to this post...taking away from any usefulness.

BTW on a "useful" note, Dave your track times with and without the MEVI almost perfectly match my calculations. I calculated -0.26 sec 1/4 mile times with the MEVI based on the torque improvements on the high end. That almost perfectly matches your -0.3 sec. In other words, I believe your results. When predicted and measured results agree, you have a high confidence that the measured results are accurate.

 

Well said.

 

Its verified and proven in cartest also. Now the limiting factor is the 6500rpm rev limiter and/or tire size. 1 of 2 things are needed to get over 98mph:

1. 225/60-15 or 225/55-16 tires those would give one 100-101mph @ 6500rpm instead of 95-97mph @ 6500rpm with stock tires.

2. Higher rev limiter, IIRC without a G-force or JWT ECU it isn't happening, otherwise 6800rpm is all you need with stock size tires or equivalent.

 

yeah, the DC peeps are really dragging their feet on the dyno day. i'm trying to be patient, but i doubt i'm going to wait much longer.

 

Good points. Yeah, I'm constantly bumping off the rev limiter now with the VI. I could use (I estimate) another 4-500 rpms. I should try and find a spare ECU to drive on so I can send my GForce in to be reprogrammed for a higher rev limit. Hmmm...

 

Anyways, nice work dave. I'll be heading out to the track tomorrow to do the on/off test as well. However I am now afraid to post that information because people will think that I running in 60 degree weather in august with a VI supercharger....

 

 

OH wow.. nice work dave.
This is all the proof I need to know that MEVI works.
If you are still unsure if MEVI works, Dave B is a 1/4 machine. His time slips are accurate indicators of how well a mod works or not.

MEVI will complement my nos very very nicely.....
hmmmm....

 

I thought the G-force ECU removed the rev limiter, but was recently corrected by an .org member. they said the G-force removes the speedometer limit.

 

I definitely would not want the rev limiter removed, just increased. I don't think G-force touches the rev limiter at all. Speed limiter yes, rev limiter no. You would have to go JWT...

 

we're expecting snow tomorrow and that track is downhill so that should help those times Just had to post that. I may see you there tomorrow. If not, good luck w/ you runs. You've got new rubber now right?

 

Don't forget the 50 mph tailwind!

Yes I have new tires.

 

The JWT ECU raises the rev limiter to 7000 RPM.

 

I love all the doubters. They think we are all crazy. The intake makes a big night and day difference. It's hard for some to grasp all of the different variables that come into play to produce certain numbers. If I were to do it all again, I would have made this my first mod to my car.

 

I would have never guessed this many people would have replied to this post. When I ran my 14.68@98mph the conditions were pretty sweet. It was 60 degree weather, low humidity, and a 20mph tailwind. You can go wrong with all of that. Of course it's not quite like running on a track where they let you run in 30-40 degree weather.

It sounds like we have some folks that haven't been to the track to to gauge how weather conditions affect a car. It's been my experience, in both my Z28 and Maxima, that hot and humid weather kills a car's performance. Like I said, last year in weather like this (90s, humid) I was running 15.3s@92. This was with a Y-pipe, B-pipe, UDP, intake, and lightweight 16s. In April in 60 degree weather WITH the same setup I was running consistent 14.7s@96mph. Hot air is less dense and has less oxygen then cold air. Humid air has more moisture therefore less available oxygen. A hot day doesn't allow your motor to cool either. When I ran last night, my intake manifold would have given you a burn if you had left your hand on it. Imagine how hot the air was entering the cylinders? Something that impressed me was that I hotlapped and ran back to back 14.9s and back to back 15.0s. Hotlapping is when you don't stop for a cool down. I made one pass and came back and got in line and waited 10-15 minutes with the engine running and hood closed. The engine fan, without the A/C turned on, was running most of the night. This means your engine is VERY hot.

I saw a 01 and 02 Lightning running consistent mid to high 14s@96mph, a 99+ GT with a 50-shot running lower 14s at 100, a 97 SS running higher 14s, a 92 Civic hatch with a GSR swap with turbo and running slicks getting mid 13s. A friend's 01 TA WS6 with heads and a cam plus all the usual was getting 12.9s (hit best is a 12.4).


Dave

 

I spent about $620 on everything. I plan on going to my Nissan dealer one day and I'm going to ask to look at my engine because I think I might have an intake manifold problem.


Dave

 

I was thinking the same thing. What happens if you need to get a new manifold gasket someday?

 

LOL.

Yeah, this thread turned out to be pretty sweeeeeeet.

Anywho, Nismo87, did you take into account that the trap speed is AVERAGED over the last 60' of the run, its not an instant reading? When I trap 96mph (and shift to 4th gear), as I cross the finish line my speedo is reading about 102 (I wonder how fast I'm actually going?), so you have to allow some leeway in your calculations. People are actually moving faster at the end of the 1/4 mile than their trap speeds indicate.

Using a 205-65-15 tire I'm hitting the rev limiter in 3rd at about 50-60 feet short of the finish line. With a 235-40-17, I'm probably 140 feet short of the finish line when I hit the rev limiter in 3rd. Can you calculate the theoretical maximum speed in 3rd gear with my tire sizes?

 

Cartest takes the average of the last 60' for it's trapspeed calculations. However I should point out that the I used was simular to Iron lugs or Jeff K's old megamax. Your speedo is definitly off, my se-r would show 94-95mph through the traps but I was doing 88.x at the strip.

Quote:

Using a 205-65-15 tire I'm hitting the rev limiter in 3rd at about 50-60 feet short of the finish line. With a 235-40-17, I'm probably 140 feet short of the finish line when I hit the rev limiter in 3rd. Can you calculate the theoretical maximum speed in 3rd gear with my tire sizes?

No problem, with a 205/65-15 tire your hitting 97mph @ 6500rpm. Normally when one does the tire circumfrence calculation it comes out to 6.67ft, however I actually measured the tire diameter off my uncle's 91se which uses 205/65-15s. That figure came out to 6.33-6.34ft, now that correlates with the rpm/mph ratio that is on most dyno charts for maximas. On the dynos I have 5spd 4th gens have a 50-51 rpm/mph ratio in 4th gear. Now with a 6.67ft distance that is 140mph @ 6500rpm, however a 6.33-6.34ft distance is 130-131mph @ 6500rpm. This is the same as what the dyno reads.

So here are the results (sorry for details but I try to be as realistic as possible hehe) 205/65-15 are 97mph @ 6500rpm in 3rd gear. A 235/40-17 is 93mph @ 6500rpm in 3rd, also cartest shows the 3-4 shift around 1190-1220ft so figure 130-150ft of 4th gear . The trapspeeds are about the same ~97mph. Here is where it gets good a 225/60-15 is 99.5mph @ 6500rpm. Cartest shows the car hitting the rev limiter just about 10-20ft before the finish line. Now running a 225/60-16 is 103mph @ 6500rpm. Cartest shows it averaging 99.9mph over the last 60' and it hits the finish line around 6300-6400rpm. With a 205/50-15 tire your trap is 98.2mph @ 5300rpm in 4th gear.

It seems that the best bet for ET/trap is to run a 225/60-16 tire or a 225/60-15 with the stock rev limiter. On a side note a 6800rpm rev limiter would have you hitting 102mph @ 6800rpm in 3rd gear. Cartest projects a 2975lb max with 200whp @ 6000rpm/206wtq @ 4500rpm to run a 14.2x @ 100mph with a 2.25 60'. However cut a 2.0x 60' and its a 14.0x @ 100mph, run a 1.98 or better 60', it shows a 13.9x @ 100mph. Now this is assuming no elevation and 65*F temp, 29.38 baro and 55% humidity.

 

I thought I might add that I did not hit the rev limiter last night. I came very very close, but I didn't hit it. Right after I passed thru the traps I let off and my tach was a smidge into redline. Once it cools off and I'm running a bit faster, I'd imagine I'll have to shift to 4th just short of the end. I'm running 225/50s on 16X7.5 K1s. I plan on getting a set of drag radials for my 15s. I'll probably get a 205/50R15 (ie very short tire so I can use 4th).


Dave

 

Hmm with those tires and a 98-99mph trap you'll finish around 5300-5400rpm. Looking at MEVI dynos the power at 5300-5400rpm is around the as the power at 6300-6400rpm. If you have any mustang friends with a 225/60-15 or 225/55-16 tire, please borrow them . This will allow you to stay in 3rd and the power is greater at 6300rpm in 3rd vs 5300-5400rpm in 4th. BTW those were good results for the hot weather for your car.

 

I know the short drag radials will hurt my trap speeds somewhat, but I'm more concerned about my ET and 60'. Finding drag radials in a tall 225/60R15 or 225/55R16 wouldn't be easy. I'd rather have the torque multiplication than the speed. Running thru the traps around 5300-5400rpms will be pretty good because I'm deep into the powerband which is where you want to be when crossing the finish line.


Dave

 

STRICTLY FOR FUN, I used a weather station correction program and these are the numbers I got from going on a 90 degree day to a 50 degree day. Maybe this can clear up the "conditions" confusion:

Original Conditions:

Temp: 91
Humidity: 55
Barometric Pressure: 29.68
Density Altitude: 2,707
Original results:
ET: 14.99
MPH: 95.00


Submitted conditions (correction):

Temperature: 55
Humidity: 30
Barometric pressure: 30.00
Density Altitude: -404
Corrected results:
(What you would have run under the submitted conditions)
Corrected ET =14.46
Corrected MPH =98.48


This is NOT taking into consideration my altitude of ~1100' or my pathetic 2.3X 60' or my wildly hot engine. The altitude is good for ~.15 and 1mph (I can't fix altitude since I live in Kansas City), but I can improve my 60 foots and ice my intake manifold. For every .1 I shed off my 60', I see about a .2 drop in the 1/4 mile.

Under these conditions, the density altitude works out to be 3973' above sea level and I'm loosing ~8% of my power to the weather. http://rshelq.home.sprynet.com/calc_hp.htm

I also corrected my 15.25@91.48mph from July 2001 to 60 degree weather (like when I run my 14.7s). Guess what? That 15.25 corrects out to 14.7s@95+. Hmmmm...that's pretty much what I run consistently in that kind of weather. Sounds to me like this program is pretty accurate.


Dave

 

Dave - awesome work!!

This proves that the MEVI really does what it's supposed to do.

Are you sure about this? Whenever I run CarTest2000 the speeds always seem a bit high compared to real-world results. Is there a way to change this parameter between averaged and right-at-the-line speed? If so then maybe I have mine set wrong.

PS - thanks for that database! I've been having lots of fun with it

 

That is true but remember power peak is shifted to 6000rpm and barely drops off until after 6400rpm. Either way you'd trap higher with small 205/50-15s or big 225/60-15s. In the end you'd be faster with 225/60s than the 205/50s because, you stay in gear and finish at a good rpm. What kind of rims are you going to put the 205/50s on? I figure if they are only used for the track, run on some bogarts or something that is very-very light. If you could get the wheel weight down to say 29lbs that would work great.

 

Wow, sweet info there, thanks. I've sold the 15x7" 13.5lb Kosei K1s and I am going to continue to use 15x6 11.5lb Millenia wheels. I wonder if you might run a couple more simulations for me?

I've found 2 slicks which mount on this skinny 15x6" wheel, one is a 7.5/23-15 with a circumferance of 73.0", and the other is a 6.0/26-15, with a circumferance of 81.7". What gear, and at what RPM will those have me finishing at, and what ET/Traps would I see?

I really really need a copy of cartest. Anyone care to burn it for me since I'm poor because I spent all my money on my car?

BTW another issue to take into consideration is actual tire size. Given the same specs, tires can vary significantly in size from one manufacturer to another. For instance, I have a set of 205-65-15s made by Amerigas, that are MUCH skinnier (on the order of almost an inch) than my 205-65-15 General tires. I should check the circumferance of them to see how they compare.

 

Go for the 6.0/26-15 slicks they will have you turning 104mph @ 6500rpm in 3rd gear. Your actual results might be closer to 100-101mph but never the less these are a good size tire for 5spds. With a 2.1x 60' you'd see a 14.2x @ 99-100mph with those slicks. Now assuming you didn't snap an axle or fry the clutch with a 1.95 60' it projects a 13.9 @ 100mph. The engine should be around 6200-6300rpm. But this is assuming the race weight of the car is ~3165lbs with driver. If your car is around 3000-3050lbs with driver then it would only need a 1.98-2.00 60' to run a 13.9. I just hope you don't break anything with that kind of hardcore launch.

 

Could you re-calculate for a race weight of 2920 lbs?

 

With a race weight of 2920lbs cartest shows you only need a 2.1 60' to run a 13.9 @ 102mph with the 6.0/26-15 slicks . A 1.95 60' and its a 13.7 @ 102mph. I wish you luck, on a nice cool day with the taller slicks should equal 13's with sub 2.0-2.1 60fts. I'm starting to wonder what a 11.1cr all motor VQ30 would do .

 

My 1/8 dropped by ~.2 and I gained ~2.5mph. My best 1/8 was a 9.701@74.99mph.


Dave

 

It takes more than slicks to ket a 1.9 60', it takes power. The one time I got to test my slicks it was a very hot day so power was off. I tried launching at my usual 3k and got 60' times similar to my street tires. I creeped up to 5k and thats when the 1.9's started to happen. At that rpm I am making 235hp/246tq to the wheels. I run M&H 8.5x24.5x15 slicks at ~18psi. My best times that day even with 1.9 60's were ~13.4 ~106mph, thats with out nitrous just 10psi of boost.

 

I completely agree with Mardigras. It takes some serious torque to pull off a sub 2.0 60'. I have a hard time believing an NA VQ can get sub 2.0s. Traction obviously helps your 60 foot, but it does take more and more power. Each .1 is extremely hard to come by.

Dave

 

good work daveB... you got the results I expected.

Don't go with a smaller ratio tire - I (along with ejj) did that for our drag radials and it has done nothing but hurt us. It didn't help my 60' and it really HURT my trap speed.

It's still going to be almost impossible to get into the 13s NA even with this mod... but the key word there is almost

Nealoc187 - work with JWT to get an ECU customer programmed to take advantage of the VI + other NA mods and you WILL have your 13s for sure... its the only thing you are missing IMO

 

JWT ECU is the next thing I'm planning, just a matter of when I can get the money. Every time I call them they are not too friendly, I try to ask about a custom ECU and they just say "our normal program will work fine". That may be true, I'm not sure if a custom program with more advanced ignition timing to take advantage of 94 octane (vs 91 which they have in California) and anything they can do for the increased airflow at high rpm will be effective, but I'm not too thrilled with their customer service, its the same crappy service every time I call them. I'm still in the hunt for 13s, but I think my quest will be on hold for a while since I am broke.

 

Those match the simulations I've ran to the letter. However if one had a 6700-6900rpm rev limiter stock tire size would do just fine. More tire or more revs is what it comes down to.

 

How about an 11:1 VQ33DE? Drop the 3.5L crank and rods into a VQ30DE and that's what you'd have. Dunno if that motor would detonate or not, though, without some combustion chamber work or hotter cams.

 

Or a 11.1cr VQ35DE. That would rock. Although the IM seems to hold it back some.

 

Was this directed towards me?