This weekend Eric (99Maxima5sp) came down for the weekend. He has a ’99 5spd Max with hybrid intake, and a budget downpipe. We raced several times, from various speeds. I have a ’95 Max 5spd w/ V1 Running the 3.33” pulley, full exhaust, and an ACT racing clutch. I had a friend in my car, and my other friend in his car video taping it all.

First race: 40mph roll

Expecting to kill him, I gave him the headstart. He took off, I downshifted into second, and to my surprise barely beat him. I had about 2 cars on him by 60-70mph. What really got me was the LAG. I didn’t start pulling till the very end. We raced again with the same results.

Second race: 70mph roll

So we take this to the highway. He honks three times, and this time no headstart for him. We both downshift into third, and are neck and neck until I shift into fourth. I put 3 cars on him by the time we reach 100mph. The lag was again horrible. I was expecting to pull on him instantly. We raced like this again with the same results.


So with my car barely beating the same car with 90 less HP, I knew something had to be wrong. But nothing seems to be. No unusual noises, no sign of blower failure (I can still definatally feel the boost), no leaks, nothing loose, ect. I went WOT in second gear and had my friend keep his eye on my boost gauge the whole time. He said I hit between 7-8psi everytime at redline. I took Eric for a ride with the same results going WOT in first gear. Another interesting point is I am making 4psi of boost at ~4200rpm in first gear according to my boost gauge. That sure seems healthy to me.

So what could it be? I am hoping to get my car dyno’ed as soon as I can. Anyone have any idea’s??


EDIT: Moderators, please delete my other thread with this title, my internet explorer had an error as I was posting..

 

If everything is fine on oyur intake side, maybe you have an exhaust clog? Bad Y-Pipe flex?

 

The exhaust sounds fine too. No rattling from what I heard. Even if my flex section was a little loose, it shouldn't make that MUCH difference. My warpspeed Y has been good to me every since I got it over a year ago. Erics budget y has a bad flex section, becuase whenever he starts accelerating or revvs you can hear this nasty squeek coming from the Y.

 

Do you know for a fact that you are putting down good numbers or are you just going by "feel". Have you actually dyno'd?

 

Like I said in the original post, I hope to get her dyno'ed soon. I haven't dyno'ed yet, and being that I've never felt another boosted maxima before, it's kinda hard to judge. But if I wasn't making the boost, my gauge shouldn't be telling me I am. Besides telling me my WHP/WTQ, can a dyno give me a diagnosis of specific areas that might be affecting power loss?

 

Check to see if your throwing the knock sensor code.

 

A bad knock sensor wouldn't trip the ECU CEL light?

 

no

 

the search is down again

so you have to detect knock sensor code with OBDII?

 

Switch to the Dark Side.

 

yes, either with a reader or manually pull the codes from the ecu.

dark side?

 

Have you run it at the track?

I'm .6s quicker with the 3.6" pully...that's a big difference. You should be pulling on a NA car a whole lot faster.

 

Out of curiousity, have both of you ever run at the track? If so what kind of times are you seeing?

You won't see too much of an improvement anyways until you hit mid-top end... and depending on your tq figures that extra person in the car could make quite a difference in a race.

I don't know how your numbers are, but my peak torque was at only about 230, whereas hp was nearly 270 to the wheel

Nasty squeak from the y-pipe huh? Mine squeaks on the 1st-2nd shift.. I think I will take a casual look the next time I lift the car


Oh and btw, check your plugs? I noticed a consistent 0.4sec improvement in my times at the track after trying to troubleshoot my own performance issues... you never know.. I was pulling hair out of my head only to see that it was just a spark issue!

 

thx, Confused~


dark side = smaller pulley?


5th gen engine is not very torquey.... my torque reading is pretty low too. 231lb/ft with 10psi.

was there anything happened to your spark plugs?

I re-gapped my plug from .038 to .035 this weekend. it made my back hurt from removing the plug on cylinder #5 and my performance on bed suffered too.

 

Yeah I noticed I'm wondering why though : it's almost exactly the same as a 4th gen except for the MEVI : the torque is there in stock form, but as soon as you add boost it doesn't raise torque numbers as exponentially as a 4th gen (the drop is UGLY).

I was thinking about starting a thread about this.. but why are we seeing this? Anything that we could do to increase torque... aside from running NOS on top of the boost...


Plugwise, it was just wear - copper plugs I just didn't realize it had been that long! Notice a change in performance? I'm still at 0.039... didn't want to reduce gap too low. And yeah, rear plug banks are a PITA in these cars! Did anyone notice your performance deficiency?

 

Yup! I noticed that big gap between my hp and tq reading, the tq reading was just flat. I am thinking about tuning my car to a nice 12:1 AFR with cartech FMU. Adding cat back might give me another 10 lb/ft.

I wonder how come we see more torque on a juiced max than an SC'ed max. Even turbo guys are getting a lot of torque than us. I feel my car is Honda-ed.

not change in performance when I lower them to .035. I think it just reduces the chance of misfiring by lowering the gap.

my performance deficiency? just several people....those two girls were complaining about it....the cameraman and the director too.

 

I want to dyno my car after doing my 2.5" : I know it made a difference, I just want to see how much! They say a full 2.5" exhaust will yield about 10hp and 20lbs-ft to the wheel (at least from what I've seen on a few posts between now and a few months ago)... so that's somewhat encouraging!! I wish some people would post their a/f curves as they dyno tuned, so we could get a rough idea of what happens as the curve is changed...

The nawz guys have higher torque than hp numbers in some cases... it's crazy! Ah well.... I just wish there were something we could do.

As far as plug gap though : at which point does a gap become too little and it sparks too easily?

Oh I couldn't help notice the last part... are you guys hiring? If it helped you pay for a S/C, it must be a good pay band... I'd be interested. So long as we don't share a cubicle together that is

 

It's because our boost is directly related to engine rpm. The juiced guys can get power at low rpm (torque) or whatever rpm they choose by how they set up their window switch. The turbo guys can set their boost controllers to give full boost at low to mid rpm (but they also have to have a turbo that will do it, and there are compromises involved). But us SC'ed guys have to live with low boost at low rpm and max boost at redline.

But we:
1) don't have to have bottles refilled
2) don't have to worry about boost pressure spikes making our engine go boom.

 

thx stephen for the info....for having a SC with auto...it is really hard to get the rpm to the right spot. Sometiems I boost when the rpm was 2500...the car doesnt feel fast at all, because it downshifted one gear and kits the rpm to ~4500.....and I am still far away from 6400. It feels really "linear" until 5500+.....

I still need to learn how to drive an SC'ed car.

thx for your help!

 

I thought you are on a 2.5" cat back already?? I think it yields 15whp and 11 lb/ft on iansw's 4th gen auto. Another good side is it lowers EGT by increase EG flow. Maxxboost00 has the dyno graph before and after tunning. His A/F curve was like mine (big dive after 3500, below 10:1 after 4000) and after S-AFC tuning by Kevin, it was a flat 12:1 AFR from 2000 to redline.

oh yea....too many girls and as the only male actor, I am getting too tired and no time to work on my car.

my department is full.....but dont worry, we will put you into a cubicle with other male actors in other department

Quote:

As far as plug gap though : at which point does a gap become too little and it sparks too easily?

hmmmm...about this question, I have no clue. Someone want to answer this question for me?

all I know isif there is a premature ignition.....the CEL light should blink.

 

I just jacked up my car and inspected every inch of the y-pipe. I had my brother start up the car and revv with me under, inspecting the y to make sure there was no hissing or anything. Everything is fine. There are no visual leaks and it sounds nice and tight when revved -- no squeels. I suspect that the squeeking is coming from my brake rotors heat shields that bang against it when accelerating/breaking at certain points. It's weird though, becuase it's off and on, when i'm off/on the brakes.

When I had my resonator installed several months ago, the exhaust guy told me my stock cat was half blown out. So that shouldn't be a problem for flow since it's being blown out instead of clogged up.


Exhaust is fine, boost gauge reads normal, but I only take a n/a max by ~3 cars from 70-100.

What could be wrong with the compressor that wouldn't show any symtoms?

If I had bad knock sensor(s), wouldn't I notice a significant decrease in power/ride quality? I haven't noticed any. And compression is fine I think; the car starts up fine w/o any lumpiness and my idle/acceleration is smooth.

And I know it's not the friend doing it becuase he weighs 170lbs. and my other friend driving with Eric weighs 245lbs.

 

There's no real "I think". Have you tested your compression? Either its ok or its not.

Do you have track times (and more importantly their trap speeds)?

 

craig : do you have a fuel pressure gauge? maxxboost00 and I were getting really low whp reading because our fuel pressure is not right.

 

yup i have one. it always says between 38-41 at idle, so i'm getting enough fuel. The last time I went WOT and had someone look at the FP gauge, it read 65psi @ wot.

ejj: but with bad compression you get the symptoms right? Lumpy idle/acceleration, weak start-ups, ect. I have none of these. If my compression was the slightest bit off, wouldn't I be able to tell?

 

Maybe not. That's why you should check it.

I'll ask a 3rd time, do you have track times?

How heavy are you big azz wheels?

 

Hmm..

Not yet. I edited the message above to say that, but got the error message..

18x8.5, 24lbs. each. Not really that bad. They actually help me hook up a little better then with the old 17x8's. But when your boosting 7.7psi and downshift into the meat of it, racing a n/a max, it shouldn't matter if my rims weighed 50lbs. each.

 

Just chalk it up as 99's being faster.

Does he have any track times? There are several NA guys here that would be right with me, if not beating me (Neal) if I were to race them.

Those are very heavy wheels, and will do nothing but hurt your straight line performance.

 

finally am joining this thread.


I completely expected to get slaughtered. The gap woulda been smaller had i not had malcolm (245lbs) with me.

But his car "seems" fast, just doesnt get up and running as it should. Hes definately hitting 8PSI, no question there. I have track times which are listed below, so by him beating me by 3 cars or so, hes still in the 14s, which is not where a max of his calibur should be at...

Best of luck craig, get her dynoed and stuff. I told you to fear my N/A beast Biatch...


Eric

 

When I took you for a ride, you were like wow, nice! We both expected me to slaughter you. I then took a ride in your car, and while quick, it definatally doesn't have near the punch mine has.

That's whats soo freaking weird about this situation. And it's not my bad driving!!

 

yeah, im sure that extra "punch" mine was missing was from my lack of a V1, but shes not to shabby, still to slow for my tastes.

And your a decent driver, now let a real driver get behind the wheel (:cough: ME :cough: ) and ill show you what shes made of..



Eric

 

Either my SC sufferes severely from heat soak, or our butt dyno's are screwed, or I am making too much TQ and not enough HP.

 

Pull the codes from the ECU... The KS will just show loss of power (which you think you have or you wouldn't be posting this) and poor gas mileage. Eliminate the KS from the equation. If you haven't replaced it, I am sure it's due, it's quite common.

 

Doubful. I've run back to back to back at the track (bracket racing) and have lost no performance. Unless your oil is boiling, you shouldn't have a problem.

Do you have an oil temp guage or an oil cooler?

Rumor has it butt-dyno's aren't that percise...

Don't think that's it.

If Eric's trapping at 92 tops, you should be running away from him. I would guess your car is capable of a 13.7@103ish, and that's quite a difference.

Track/Dyno that bish!

 

mathematically incorrect.. stop hoping, go to the dyno and have them hook up the air fuel.

 

By 100 you defitely should have pulled more then 3 cars.. He should have been walked if you have a 3.33 and running all your boost.. Have you even tuned it with an AFC yet?
And your running the 6:1, I used to run the 8:1 when I had the 3.33" and I think with that disc it's the best setup.

Do what I just did today. Drop it down to a 2.87" and you'll walk him

 

his car has lots of tuning ahead of it, thats for sure, im sure he'll kill me once he gets everything figured out...


Eric

 

That's what I'm wondering.

But the first thing to do is to head to the dyno-tuner.

 

 

Stephen : makes sense, but I still think we should be seeing a more even torque curve - especially given the boost that keeps getting increased as we move up beyond 4500rpm... adunno.. I can believe the 30VQ not being designed for such a high level of torque at peak rpm, but not to this level. I don't have my dyno graph handy (won't for awhile as I'm not going to be at home for the next few days), but I swear that torque curve is not showing much difference from stock to 8psi of boost at a particular point beyond 5.5k...

Anyways back to maxi-od

I got the 2.5 back in March after I lost my job - it was a gift to myself to help me feel better... I haven't dynoed since Feb however!

And sorry, not interested in the job anymore... I'm sure I can pimp myself to a few bachelorette parties up here for a good buck :P

 

I called my SC installer and were going to schedule a time to drop in the 3.125". I told him about all this and we are going to take a look at it. Then on to the dyno hopefully from there...