So I ran my car on the dyno today. It was a dynojet (Stillen's). Everything looks good. The horsepower curve is relatively straight with a small slow down from 3500-4000 RPM, but still relatively straight. I peaked 180 at 5300 RPM, and fell down shortly after. 175 @ 5750, 170 @ 6100, etc. I guess that's the conseqence with running the CAI.

Now the torque curve is totally shot. I maxed 186 at 4600 RPM. Now this is a good figure because it was the highest torque number any N/A Maxima got all day, including 5th gens. Now the problem is that it makes 182 @ 3500 RPM, and it falls to a low of 175 @ 4100 and then rebuilds back up. Hitting 180 again at 4300 RPM. Now I know this doesn't seem like much of a drop, but on the dyno printout it's a huge drop.

Not to mention I looked at all the other 4th gens with the same exact mods (one had RT Cat & UDP though) and they remain relatively flat. This is kind of annoying, although it really doesn't affect me that much because when dragging the car only hits 3500-4000 in first gear, but still I don't know what the problem could be.

Another note, this dyno was done outside in extensive heat ~90F and the fan was so small it was practically worthless.

Anyone have any advice on this torque curve?

 

Actually its just a vq thang

Check out andi's stock and intake/y dyno.

http://www.boostaholic.com/maxima/dyno/index.html

His modded chart is just like yours....he kinda gets a high at 3500....drops a little....then peaks up at 4500.

Your car is fine

 

Yeah well mine drops a bit more, maybe I'll scan it. I did look at the other 4th gens and yes they dropped a bit, but mine dropped easily 5 times as much as their's did.

 

any SC maximas dyno?

 

HAHA a 5th gen, put out 208 WHP, and 211 Tq. Hoon with just intake and ypipe on his 5th gen put out 200 WHP. That guy was kinda ****ed, his SC was totally not boosting.

 

First off, I've never heard of a NA 4th gen VQ holding on to 170fwhp up 6100. Every dyno I've seen shows the VQ dropping power after 5800. Are you sure their dyno was reading accurately? Most VQs (including mine) are in the 150-155 fwhp range at 6100. The intake manifold just doesn't have the ability to breath due to the long runners. If your car does make power to 6100, you should be a bit quicker than a 14.7@94mph.

No worries, my Max does the same thing. My peak hp occurs at 5400 rpms (175). My dyno curve gets really big from 3200-3500 rpms (191 ft/lbs) and then drops into the 180 ft/lb range and then shoots back up to 193 ft/lbs (190 consistently from 4200-4700). My Maxima is a bit weird because I seem to make a bit more torque than most NA VQs, but my HP is on the lower side. I'll be dynoing my Poorman's CAI 2.0 and a UDP here shortly.


Dave

 

Yeah Dave your torque is high. Actually I'm mkaing 172 WHP at 6000 RPM according to this dynojet, and 170 at 6100 and like 166 at 6200. Torque falls hard at 5000.

 

well. u know why your torque/ hp curves drop so hard after 5k right? C. A. I.

i was racing Nabil on the freeway home after Stillen Open house, we did three 3rd gear punches at 60mph, and each time, Nabil kept walking on me. by 110 he was 3 car lengthes ahead. #@!
the reason?
1. his is a 96 that utilizes the ecu upgrade to the fullest,
2. his Volk rims are reallly really feathers compared to my brick Revos
3. He has a Stillen Intake. i have the place racing CAI...

i think i'll be going to So CAL SERCA Dyno day on May 19th to see what improvements the UDP and subsequent swapping of the CAI to the SI will do..

 

I measured my HP with my G-Tech and got 173 HP to the wheels! That actauly seems pretty darn accurate. I love this thing.

 

173 with the supercharger?

 

Hey Cheston, your car held on pretty good dude on those 3 runs. In fact, it seemed to be stronger than other 4th Gens I've run against, so I'd say that ECU mod you got last was worth it... So don't sweat it too much.

As for Brian's dyno run, I wish I'd seen it Brian. We could have tried to pinpoint the cause of that dip in power that you're describing. By the way, what power mods do you have in/on your car these days?

But just to give you a reference, my car put down 186hp/196ft-lbs torque (before I got the UPRD/G-Force ECU mod), with just a Stillen intake, Y-pipe, & muffler for power mods.

 

----------------------------------------------

That's the test I'm waiting to see! (CAI, then SI on the SAME car).
Please post your findings.

Terry

 

Cheston-

I wouldn't sweat it too much that Nabil beat you by 3 cars. Those 18s are heavy and make a big difference no matter what speed you race from. I think it's pretty safe to assume that at least 2 of the 3 cars lengths he put on you were due to the wheels. When I ran my 17s which were 10 lbs heavier than stock, I was lucky to run 15.2s@91. With the stock 15s, I ran 14.9s@94. With the lightweight 16s, which are 2 lbs lighter than the 15s, I'm running 14.7s@94 (et improvement was mostly due to the tires). Overall, 3 mph and .3-.5 was lost to the bigger and heavier wheels. What's that Revo combo weigh? I'm guessing with tires you're pushing near 50 lbs plus you've got that inertial weight further out on the rim which makes things much worse.


Dave

 

Before anyone starts pontificating on Cheston's nonexistant 18" wheel disadvantage (he rides on 17" wheels), let me assure you that the race outcome wasn't just due to the wheel weights. Remember that the 3 runs we did were done from a rolling start of 60MPH in 3rd gear (both cars are 5spds), so wheel weights and their momentum weren't as pronounced at those speeds as what one would expect from a standstill start.

Also worth noting here is that Cheston has an Unorthodox Racing UDP installed on his Maxima whereas my car doesn't have one. The UDP's effect is not unlike that experienced by having the lighter wheels, so let's not forget that either. Another something extra he's done on his car is the more aggressive ECU tuning that G-Force has performed for his car.

As for the CAI vs. SI debate, you should know that Cheston's CAI sitting in his '97 GXE's open foglight chamber SHOULD have given him the much-ballyhooed advantage of "ingesting cold air at highway speeds". But it didn't. Why am I not surprised?

In fact, on the 3rd run, I wanted to make sure that it wasn't something like me getting the jump on him first, so I waited to hear AND see his car growl and start pulling ahead before I laid into the throttle, only to end up with the same result as the previous 2 runs.

So the wheels may have been a minor factor at best and they were easily counterbalanced with Cheston's other mods which should have given his car the edge.

My advice, lose the CAI's lower piece Cheston and come to the dark side.

--Nabil

 

yo yo, what up brian[v]

 

Sup Norton!!!

Nabil, yeah your numbers are much like DaveB's. It makes me think that Stillen's dyno wasn't that accurate. All the 4th gens were producing substantially less torque than the dyno's that are floating around this board.

I am very tempted to ditching the lower CAI piece and going with the SI, similar to your setup. CAI piece before MAF, velocity stack after.

I'm sure your car is quicker as well. Lighter rims, lighter car (you're car always seems to be pretty empty), and the more accurate tuning of the pre-97 UPRD ECU on your pre-97 car. Even your dyno figures came out higher, I'm not surprised.

 

BrianV,
We see this torque dip quite frequently but it seems to be more common on the 1995 cars. If you have a fax number handy I can send you a before and after dyno sheet that shows the DIP with an intake and exhaust, then an after with an ECU upgrade. The torque curve is much more flat, almost completely so. I think you'll be surprised.

 

I believe the SC is on his I30, the Max doesn't have it. Am I right?

 

Robert actually I have nabil's and cheston's dynos here so I'll take a look at them, thanks man. I still want you guys to break into these 97 ECU's and make an ECU just for this car.

 

Nabil-

I completely disagree. I incorrectly stated that Cheston's Max had 18s. However, I did research the weight of the 17" Revo and they weigh a whopping 27 lbs! Your Volks weigh a mere 15s. 12lbs of extra unsprung is SIGNIFICANT no matter how you cut it. I'm not trying to be be brash, but I honestly believe I have a lot more experience with the physics behind drag racing than yourself. I've been involved in drag racing for about 7 years now and have been involved in both domestics and imports. As much as we all want to believe the Maxima makes a "ton" of torque, it doesn't hold a candle to a nice V8. The Maxima struggles to spin big heavy wheels and I've seen the differences with over 40 1/4 mile passes on my car alone. The smaller the displacement of the motor (ie less torque), the more weight (unsprung, overall weight, inertial) is a factor. I don't care if you run from a standstill or from a roll-on. The car is gonna be slower both down low and on the topend. Contrary to popular belief, just because the wheels are spinning doesn't mean they are any easier to accelerate in a roll-on race. Like I said, 12lbs is huge and I had no idea that those rims were so heavy. His combo is easily pushing 52+lbs. I'm pretty certain his car would be very close to yours if he was running his stock 15s (which are still heavier than your 17" combo).

The UDP does reduce inertial weight, but it's not quite like adding lighter rims. Since the weight is literally mounted to the crank and is relatively small in comparison to a set wheels (both in distance from the motor and diameter), the gains aren't going to be nearly as substainal.

As for the CAI vs SI debate. I don't think either makes a SQUAT of difference. They will both perform well at speed with the CAI performing slightly better than the SI when underhood temps are high. Let's get real serious, it's not like the SI is a supercharger or NOS. We're talking about 1-2hp difference between the two....at best (read: insignificant). I've already shown that the underhood POP style intakes make no more power than a well thought out stock setup (I've dynoed and track tested each setup). How do you contest that? How does that support your claim? Would you not agree that the POP setups perform better on the dyno simply because the hood is up? I can show you a few dynos showing UP TO A 13 fwhp LOSS with a POP style setup when the hood is closed and the engine is hot.

I think your car might make a little more power than Cheston's, but he is sporting a bit more equipment and gear than yourself. I think that with lighter rims, Cheston's car would be DAMN close to your car. WHy don't you guys try and prove me wrong? Throw his 15s on the front and see what the outcome is. I bet it would be within a 1 car length. BTW, do the roll-on race from 60-95mph. This should be more than enough of a race plus it will negate any factors like who can shift faster.


Dave

 

.

 

I think someone is trying to become a maximaniac....
moderators...where are you?

 

Dave's right 12 lbs on the rims does make a difference. 12 lbs is A LOT of a difference actually. I'd say that 12 lbs saved on each rim could equate to a 1/4 mile time up to .2 seconds lower, maybe even .3

 

I have a 1995 SE graph that we used a year or two ago in long term testing, the car had 160,000 miles on it, and the dip is really bad. It seems that the earlier cars had a more noticable drop off.
Let me know if you want to see it.

 

I've got a pretty substainal dip. I've got a 96 SE built in Jan of 96, currently has 68K miles.


Dave

 

Long term ECU upgrade test Maxima
95 SE 160,000 miles last time we checked. Serious DIP before the ECU upgrade. Also had a cat back and a pop charger.

 

Thanks Robert, I'm still impressed a 160K 95 could put out 174 WHP wit just those mods. Quite impressive Nissan

 

definately.

Do you feel better about your torque drop off? I know its not this this bad right?

We theorize that Nissan Engineering programmed this curve with the 2 peaks and the dip for 2 reasons.
1. Elimination of torque steer. Most companies do the same thing, to a lesser degree.
2. Peaky Torque/power curves are more exciting to the average driver.
A flat torque (and power) curve is boring. If you make a low end peak, lets say 3000 rpm, then a droop in the Mid, followed by a top end peak the car will feel a lot faster to the public.

There is no doubt Maxima production cars Engine control programs are detuned.

 

Robert yeah, actually mine is just about that bad. Hey sometime this Summer I'll stop by GForce and I'll bring in the dyno sheet, and I'd like to talk to you about possibly chipping my car.

 

Here is a dyno that Biomax did of the 95 JWT ECU vs the 97 stock ECU. With the JWT ECU his engine seems to rev to 6900rpm before hitting fuel cut, does any know what the stock fuel cut rpm is? The 1st 3 runs are with the 95 JWT ECU and the last 2 are with the stock ECU.