Well - it was kind of a cruddy day. Went to the Dyno and numbers weren't what I was expecting. Turns out the VI is opening under vacuum but not under boost - which tells me the vacuum canister isn't doing it's job.

So we did runs with the VI zip-tied open. You can see the difference below. That made me happy. My friends had been guessing 350hp, but I knew better with previous experience and I guessed 320 - I was 1.8 off.

Then - my starter and/or ignition switch died right there on the Dyno - so I didn't get to tune as much as I wanted to.

Had to roll it off the Dyno and pop-start the clutch to get home.....

Also - no matter how much I richen the AFC up top, the car still leans out a bit up there. Nothing seirously dangerous, but still more than I'm comfortable with. At one point I had it set to richen 23% at 7000RPM - it got leaner on the run. Otherwise the AFC worked at lower RPMs.

Mods:
JWT ECU
V2 Polished SC (on V1 Bracket)
2.87" Pulley
370cc Injectors
MEVI (one run opened the whole time, one closed)
Apexi S-AFC
Chromexed Ceramic Coated piping
WSP Y-Pipe
WSP Straight Pipe
WSP B-Pipe "fix"
Stillen Muffler

Turns out I'm not running very rich at all throughout most of the band.
All runs in 4th Gear



IanS

 

First of all, congrats! 321 hp is awesome!


The reason you are leaning out at high rpm is because you are exceeding the flow measuring capacity of the A32 maf, which is only good for a flow corresponding to 350 crank hp. You are well beyond that with 321 at the wheel. But as far as injector duty cycle is concerned, you should still have some headroom with the 370's, so I'm not sure why the SAFC isn't making a difference.

But unless you send the ecu back to JWT to have it programmed for a Z32 maf, it looks like it's going to take some tuning with fuel pressure to deliver the needed fuel at high rpm. You still have that Cartech fmu, right?

 

I thought at WOT the MAF was in open loop!?

Anyway - yep - still got the Cartech - I'll throw that in once I figure out why my car won't start.

 

Looking good!

Thats actually about the limit of the 370's too.

Time for juice, or bigger injectors.

 

At WOT the ecu is in open loop, which means that it ignores O2 sensor signals and reverts to programmed fuel mapping curves for injector duty cycle, but it still has to know how much air is flowing into the engine, so the maf is still being used.

 

Oh man...whole nother can of worms...heh...maybe I should just stop now.

 

Great Numbers

congrats

 

Here here. Also had good reason to keep the Aux Fuel pump on too. That one run when you went really lean that the dyno couldn't chart it was a scary moment.

I really think your starter is toast. That one day when the CAS wire got goofed up didn't help the starter any.

S

 

Yeah - I think you're right.

Never buy a Walbro used I learned today. I've got another one I need to install - but yeah - no more running without the Aux Pump.

 

Thats about what Jay had too... noice

 

Yeah - except JAY25 did that on a 3.25" Pulley @ 10PSI.
I'm on a 2.87" @ 12PSI

Now I'm depressed.

 

I guess that goes to really show, no 2 cars are alike.....

 

Good number dude!!!!!

 

Alright, something is starting to bug me and maybe some of you guys can answer me on this. As I look at the dyno chart, I notice that Ian's car peaks at 6500rpm, and begins to drop. Though it's not a step drop, nonetheless it's a drop. Now from what I hear theoretically, when we look at someone with the stock ecu/rev limiter, boost, and MEVI, the curve is still climbing when it hits the rev limiter. It was assumed that with a raised rev limiter and MEVI, it would just keep climbing and climbing. This is even more so with a S/C as it progressively building boost until it maxs out. Now am I making the right assumptions. If so, why is it that Ian's power drops off well before the 7200rpm rev limiter? Ian has a says it maybe the JWT retarding timing. Can anyone shed some light in this. It maybe that I'm making the wrong assumptions, but any explanations would be good.

S

 

he says that it starts to lean out up top so maybe it could be do to that

or it could just be that the engine loses to much efficiency at 6500rpms

 

Oh yeah, I didn't notice he said that....I thought he worked that out when we were at the dyno....but I guess not completely. But are my assumptions correct?

S

 

The main reason you are not getting the 350whp you should be able to get with the 2.87 is because of the JWT ecu and its conservative timing. It is programmed to pull timing as the maf signal increases above what Clark/Jim see as a safe level for the VQ. For example I had stock ecu/inj with a mevi and a 3.12 and put down 325whp and 270tq and this is basically with less boost but more timing from the stock ecu. I would expect the reason for the tailing off after 6500 has something to do with this reduced ignition timing as well.

I read not to long ago that, Stephenmax, that he had experimented using a Z32maf and run the stock ecu with the 370cc, you should have more headroom for airflow tuning with the safc. Right now the A32 maf is not able to do anything the safc tells it to due to being maxed. Check your peak hold on the airflow on the safc and I bet you are around 100% after a redline pull and this is a sign of a maxed out maf.

I would try to get a Z32maf to use with your 370's and run the stock ecu and tune with the s-afc. The larger range of the Z32 maf and the corresponding ability to deliver fuel with the 370's should be a great compromise however I am not sure how it would idle. You have an adj fpr so you should be able to compensate for that with lowering the base fp.

 

Wow. That blows my mind. I've been posting about the JWT ECU for months and asking if it's a good idea and making sure I'm modding my car right and noone's ever said anything like this before. I've never seen a post saying the JWT ws a bad idea in any respect.....until now. I did see Stephan Maxes post, but of course I had already spent the $$$ by then and I didn't think how it related to the JWT specifically.

It does make sense to me however. Maybe I should go a different route like you suggest.


Of course, going with a 2.87 and the route you suggest wouldn't make me 350hp anyway. Going from a 3.12" to a 2.87" doesn't add 30-40hp. As I've seen, swapping pulleys usually adds 15-18hp for each size down. I would probably be at about 335-338 given your example above. The raised redline (longer runs in each gear) may make up for that at the track.

I never expected 350hp - I expected 320. I got that....would have been nice to be a little surprised tho.

 

on counterpoint, i put down similiar numbers with a 3.33, jwt - max maf/370cc & mevi. perhaps this gives credit to jwt's recommended limit to the max maf. perhaps iansw leaning out up top is evidence of the same (maf limit).

 

you should still get a z32 maf (50$) and get jwt to reprogram your ecu for the MAF (100$) that should take care of your leaning out up top problem. that could yield you another 10 or so whp

 

I dunno.

For now I'll just leave it as it is and then I guess I'll eventually buy the Z32 MAF and try to run it on the stock ECU while I have the JWT reprogrammed, then I'll put the JWT back in so that I can see the differences.

If the car doesn't run well on the Z32 and 300zx Injectors with the stock ECU - then I have a problem - because JWT is a 12 week wait.

Confused - your numbers are very freakish. I've never seen anyone but you hit anything like that on a 3.33" or even a 3.25"

IanS

 

No doubt, I was amazed by those numbers confused. So I guess pretty much Ian's issue now is the MAF is at/past it's limit, and the JWT is compensating with less timing?

S

 

I believe confused may have a slight adv due to his bored t/b, nothing major but his setup is definitely a very efficient one. Ian I think your setup is doing very well considering the mevi/rpm switch giving you problems. I wish I had my s/c and mevi and the power back again.

One thing I noticed is that your a/f is slightly rich throughout the meat of the powerband probably another safety precaution. I would try maybe leaning it out slightly to ~12.5:1 and see what happens. It would be interesting to see what a Z32maf/370's/stock ecu would do when properly tuned with a safc. Good luck and the setup looks great.

 

IIRC, Jamie has a full 3" exhaust?

 

Well if he runs a stock ECU with the 370cc injectors, wouldn't it run pig rich though this may only be really down low? I know what other's have done was put a AEM FPR or a SARD in to lower base pressure which may help the with that. I know that the S-AFC can only correct up to +/- 2 points....or at least that's what I've heard from Ian anyway. Also, I've seen not with Ian's stock ECU, but Eric's(Max1man)'s ECU, there seem to be an issue were the ECU couldn't provide enough timing, so couldn't this also be an issue? Sorry if this is annoying, I'm having trouble seeing how this would work. Maybe I'm missing something?

S

 

freakish? naaaaaahhh.... confused perhaps

 

No sir.. 2.5 either stillen or greddy

 

It wasn't the RPM switch I figured out - it was a small hole in the canister.

Anyway - fixed that today and went for a drive. Torque Steer like a ****....Bitter-sweet.

Don't get me wrong everyone - I am DELIGHTED with these numbers. Compared to the meat of the SC guys, I'm coming out up top. I am definately the fastest Max in the Northwest, with MaxiMan and BlackCat always nipping on my heels.

But I think it's awesome you all are so willing to help me squeeze that much more out of it.

I'm going to take some time and carefully think about my next move before I do it. I want the next jump in power to be both cost efficient and upgradable. Everyone's ideas here have very good points to them - I just need to consider carefully.

Also, it'll be nice to just take a few days and just enjoy it.

Compared to my boost loss issues for over a year, I am very happy to be having these "problems" now.

I love Maxima.org!!

(Now if only I could donate!)

IanS

 

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GOt the starter replaced today - funny that it did go out on the Dyno.

So now she's running beautifully and the only mod I'm going to do for a few months is get that 3" Exhaust installed. Then go back to the Dyno and solve the "is 3" exhaust better?" question once and for all.

 

If he starts to lean out slightly, then he should make more HP, not less (by my estimates). Running it richer would actually cause you to drop some ponies up top...

I say buy another MAF, dis-assemble it, and use larger diameter tubing for the housing. Or in other words, hacked MAF. And whatever volume you increase the MAF tube sizing by, increase the injectors size about the same. Check some of the 240sx boards (and freshalloy.com) for info on this. May be able to to give you some more HP for not so much money.

 

Hey Ian! Mad props to you man! Hopefully I'd like to get a test drive before you move to Phoenix!

I've put a stop to any further major modifying of the Max now. I have the fuel pressure gauge ready for install but I haven't had the time because of some house painting and renovating. So that's the last thing I'll do to the car. I'm seriously thinking of getting back into ice hockey again after a 20 year absence and spending some coin on revamping my goalie equipment. Already spent some coin finishing my home theatre project with a new Velodyne subwoofer.

 

Hmmm.. im wondering... have you thought about an intercooler? You are running some pretty high boost, and the air going in the manifold is probably VERY hot.... I'm suprised you don't have any knocking problems yet .. thats good! .. did you run any spray at all with that run? 320 is pretty dang good if thats just straight up boost :-D ... what kind of difference do you think it would make if you had an intercooler... lets say size... 25"x13"x3"

 

Intercoolers don't seem to help, but only hurt SuperCharged Maximas. This is from every thread I've read on the subject.

People report that they lose power, and noone has said they gain. Too much PSI loss through the Intercooler and bends to make cooling a charge that isn't all that hot to begin with worth it. (Compared to a Turbo setup)

I don't have any "spray" installedo n my car.

 

Ditto. Probably better off doing water injection, or a small shot of nitrous for a cooling effect. But at a charge temp of like 120-150 degree....I don't think it's really too much of a worry. Now a turbo...that's a different story.

S

 

Thats strange.... who here HAS done an intercooler setup on a S/C? And what kind of setup did they have? What kind of boost levels? and what kind of intercooler? I read an article from HCI that had a S/Ced 2000 maxima, with around 10-11 lbs of boost, and a 4x8x2.25 intercooler. He DEFINATELY did not lose any power, but gained 40hp to the wheels. from what I recall, the article said it was JUST from an intercooler swap. I will have to go and look at the article again just to make sure, but the VQ30DE-K should be very similar to the VQ30DE, with obvious intake diff and a few internals... but 40 hp... wow.

 

4x8x2.25? That's tee-ninecy, unless that second number should be 18 or 28.

 

I know... it was a Tinee weeeny one... but like i said, i am just remembering this off the top of my head... i will get the exact numbers off the article later on... but if the intake charge temps are going up to 200 F, the intercooler, I think, would help out a lot.