Last April, I Dynoed my car with the following Mods:
V2 SC, 2.87" Pulley
370cc Injectors
SAFC I
MEVI
Open 3" Exhaust (Y-Pipe to muffler)
JWT ECU - 370cc/SC Program

WHen Dynoing that day, I was laning out up top due to the A32 MAF not being able to compensate for the extra boost. I was at over 14:1 at 6500RPM.

Since then, I have added 2 things:
1) Resonator - the type with the bumps inside in a swirling patern. My exhaust had just been way too loud, and this helped greatly.
2) Cartech FMU - trying to use this to tune the fuel above 6000RPM to make up for the A32 MAF not handling things up top. Tried a 300zx MAF and JWT Chip for the 300zx MAF, but the car didn't run well at all and barely idled. This is likely because my ECU is for a 95 and the chip I bought used didn't work correclty as it was from a 96 ECU.

So I Dynoed today to try and tune the A/F and thereby fix things up top and get a smoother A/F Curve, hopefully resulting in more power.

This is what I got: Red Line is the Dyno back in April, Blue is on one of the runs today.




And here is the A/F Maps:


I did 10 or so runs today, and the Cartech and AFC were barely adjusting at all. The reason the line flattens out at 10:1 is because that's the lowest the Dyno would read. I likely dropped down to 9:!.

So here's my theories...someone help me sort through this:

1) The Resonator hurt my midrange Torque BIG TIME. I need to get a better resonator instead of this one with the "lumps" in it, I should get a straight through one with baffles. (I'm talking about BEFORE 5k RPM when I go super rich)

2) I can't figure out why the Cartech isn't adjusting very much at all. I adjusted it with the center screw all the way out and bleeder all the way out, and then tested with it 8/10ths of the way in, and bleeded closed. Got nearly the same results. WTF?

The Cartech was hitting about 92PSI of FP at 6800-7000RPM every run. Adjusting it did nothing. HOWEVER - when unplugging the Cartech from the vacuum at idle and turning the screw, Fuel Pressure chagned accordingly. It seems the Cartech was working ,but was not adjustable. I richened the AFC up 37% at 4000RPM just to see what happened, and there was 0 change whatsoever.

Another interesting note is tha when I left the Dyno, I was driving down the road and the Fuel Pump just gave. At 5000RPM the FP{ dropped to 20 suddenly and car hesitated badly. I pulled over and plugged in the Aux pump and now it's fine. Drove it home that way. This is a brand new Walbro pump I've had maybe 2 weeks. It never acted up on the Dyno.

3) I've at
Any ideas on why the Dyno gods were against me today!?

 

Those are some nice #'s

 

Those numbers suck. I should be 350-360hp and 290tq easy.

 

I don't know jack about the cartech, but how do you feel about an electronic exhaust cutout? You could keep the resonator you have right now for quiet around town operation, and open it up when you want the extra power. Just a question of if you can deal with the noise and not having as much power on tap if you want to keep it quiet though.

 

well I was saying those #'s are good considering the problems you are having,but if I could see 338 at the wheels in a 3rd gen I would be streight

 

I know...sorry to flame....I'm just so right now! Grrrrrr.

To answer Nealoc - I want the power on tap all the time...so I'm thinking a straight through instead of beveled resonator will do the trick.

That's what I get for buying a resonator off EBay.

ANyone have any links to decent perforated resonators? I can find mufflers online that are round and look like resonators. I expect they're the same thing, correct?

But really the resonator is the least of my worries. Why adjusting the AFC and Cartech didn't help worth jack is what's really making me angry.

I'll probably just get another chip from JWT and try that route again...which I don't like, because it's not tunable.

 

Cattman has a resonator (huge!) without the "humped" baffles. You can see pics of it here on my cardomain site http://www.cardomain.com/memberpage/474502/15 I don't know whether or not he sells it outside of the catback system of his though....

I had something similar to this happen to me, but not 2 weeks after installing the walbro... more like the 2nd drive around the block... Turns out the problem I had, was that the fuel pump "screen" - the filter bag that attaches to the bottom of the pump - was being compressed by the fuel pump housing (the big white bucket the pump is in) and not letting the pump suck up any fuel. We had to shave some more off of the tabs, on the top of the fuel pump, so that the filter bag wasn't pushed against the bottom of the "bucket" so much...

good luck...

Oh, and by the way, Very nice numbers!

 

what about the magnaflow resonator budget uses on their resonated b-pipes? tahts what i have...would that be considered a good resonator for performance?

and all this time people said resonators dont hurt performance...its all about the type u get....

 

Ify ou look at Magnaflow's website, they don't use the word "Resonator" anywhere....that's what I'm confused about.

I think they just call them "round" mufflers.

beveled resonators obviously hurt performance. Perforated (as in the link above from HNDA ETR) may not hurt performance....I don't know.

Looks like my brand new Walbro is toast. THank god I never removed that T-Rex Aux Pump from under the hood - that's the only way I got home.

As for the Cartech and AFC, I wonder if the JWT ECU is keeping any adjustments from working properly. ALthough I can see that as a possibility with the AFC, I don't see how that's possible with the Cartech, because it's mechanical, not electronic and the JWT can't "see" it electronically.

 

you gain 6 ponies but lose 18lbs of torque WTH!! something is not right for you to lose that much torque. At what RPM are you opening this cut out?

 

nice numbers

 

Get the correct Z32-MAF chip and it should be much better

 

I don't have a cutout.

Full 3" exhaust with a crappy beveled 3" resonator.

 

Yes Mardi, I agree with you.

But mostly it's just perplexing my on why the car wouldn't tune.
Stephen Max had this setup for a while I believe, and it was very tunable.

Anyway - I'll likely be calling JWT tomorrow morning.

IanS

 

hey Ian
I just got the Budget B pipe with resonator. Its a 14" Magnaflow. I haven't put it on yet. I'm in the process of swapping out that #$%@*! pulley!

 

is that 3" exhaust?

 

The Budget pipe is 2.5"

 

man...iansw...you're right, you should be putting out a lot more power than you are getting with that setup...somewhere along the lines of 360whp or so....ask stephen max about the cartech issue....he usually has the solution/answer to everything!!! anyway, good luck...and hope to see some new #'s from you soon

just for fun on the dyno, you should have unbolted your resonated b pipe section and just let it flow out the y pipe and see what your torque would have done to know how much that resonator is holding you back....anyway, I have no clue why even with the cartech set the way you do, it's still leaning out like crazy up top....which is killing your power...your tq is gone simply b/c with the cartech you are a lot more rich....in the midrange....

on another note, hearing that both of you had your brand new walbro's go out so quickly is disconcerting!!! to say the least....now I am worried when I get my walbro and S/C on!!!! has anyone else on here had such a brief ownership with their walbro?

 

No - it's the resonator. The loss in tq begins before I go rich from the Cartech. Admittedly, it does then get REALLY bad when I go rich. But it looks like the loss in tq is across the band besides that major dip at 5k.

Actually, from 3500-4500RPM the A/F Ratio is sort of equal to last time. at 4500, it's 11.5:1 - perfect.

As for leaning out up top, I'm not really all that lean at all right now. That spike at the end is from the end of the run spiking the A/F, and I don't actually think it is true to life. Now - before, I was pretty lean.

Why the Cartech wasn't adjusting in any concernable manner is very confusing, seeing as I adjusted it the extreme one way, then the other, and got the same readings on both.

Also, the AFC not working is another puzzler.

Like I told Mardi - I'll probably just grudgingly try and get the 300zx MAF working properly with a new JWT chip.

 

I bought this one from summit racing but I haven't installed it yet.

Outside of the timing advance you can still play with the fuel pressure via an adjustable FPR. It doesn't surprise me that a FMU + SAFC wasn't able to get the tune correct. I'd recommend that you get some kind of OBD-II logger so you can get your timing advance, maf flow, coolant temp, and fuel trims. If you did get a jwt ecu all you have to do is just adjust the base fuel pressure to get the A/F curve leaner or richer.

 

Linky no workie.

I already have a JWT ECU. In addition, a FPR alone won't work because then I'll either be rich or lean across the band. It won't help from 6000RPM and up exclusively. To achieve FP raising only in a certain band, I need an FMU (Which is just an FPR that reacts under boost anyway)

Why the SAFC didn't work at all doesn't make any sense either...except above 6000RPM, where my MAF can't read. That would make sense. But the SAFC wasn't even working at 3000RPM, much less anywhere else.

From what I can see - there really is 0 logic as to why these adjustments wouldn't work just as well on a JWT ECU as a stock ECU. Stephen Max as I understand it ran this EXACT setup that I'm running for a while, and it was easily tunable. Which brings up even more questions.

This system SHOULD work. I see no reason why not. Which is why it's so perplexing.

But oh well - no biggie - I'll get the Z32 MAF JWT Program and be done with it. Just sucks that then I can't tune it whatsoever is all I was saying.

 

Key word "SHOULD". Saying that already says there is a good possibility that it won't work....and it didn't very well. Don't forget you have made some progress....your not lean up top like you we're before....though that nice shot on the graph at the end of that run is interesting..... Was that not one of your goals? If not, let me know because I thought that was your goal, and you know I don't like to assume something...then be totally wrong.

If you want a resonator, you want the smooth perforated type. It will make the car a little louder than it is now....but at this point, I don't think that really matters if your going for numbers.

S

 

What can I say? I have been able to move the afr up and down at will with the Cartech. I've never tried adjusting the JWT tune with the SAFC.

 

Under 10:1 was not one of my goals. And saying it "SHOULD" work implies it SHOULD work.

And per StephenMax's reply above, it definately says there's no reason it shouldn't work.

 

I thought you wanted to fix your leaness up top....which you did too well, but for some reason thought it was the main goal. As usual, I end up being in the wrong. My apologies.

So the question is....what did we miss or do differently that caused this to not work? I wouldn't be surprised if it was something I did since I did hook up the vacuum lines wrong when it was first setup.

As for my point when you say "should", I was meaning to point out that there could exist some uncertainty in the results (and there was)....but from what you said, that's meant to say it will work? Am I understanding this wrong?

S

 

It means there's 0 logical reasons why it shouldn't work. Therefor the world "Should".

The FMU is hooked up after the FPR on the return line properly and is on the same line as the other boost signals at the FPR. This is exactly how I've always had it hooked up, and in the past, it always worked fine. In addition, doing the "unplugged vacuum" test by turning the **** and watching FP rise works, so I'm sure the Cartech is mechanically sound.

It is hooked up right. And it looks like it is functioning properly. Peak FP without the Cartech was 59PSI. Now it's 90+, and starts raising at about 5000RPM. This shows also that it's seeing boost.

What I'm saying is - as you remember before when you hooked it up on the wrong side of the MEVI check valve, it wasn't going above 59PSI because it wasn't seeing boost. Well - 90+PSI says that now it is....so it's hooked up right vacuum wise, and it's place in the fuel system I know is correct. Because it also wouldn't raise FP if I put it on the incoming from tank side, for instance.

It's working, it's just not adjusting.

IanS

 

Take the cartech apart and see if the diaphram is shot...I just had mine apart and i bought the rebuild kit for it...$35 and you set with all new rubber, and a metal shim..

Tray at cartech said that if that metal shim is bent the slightest bit, it wont adjust

-matt

 

Now that may be the problem!

Thanks! I'll take her apart this weekend.

IanS

 

Looks like I need to buy this:

http://www.a-1performance.com/magnaf..._6round_ss.cfm

PN 14641

 

A peforated core is far less restrictive then a louvered core.

You might consider running a VES from ATP. It would be as quiet as even a stock catback and then you set it to open at X-psi. Best of both worlds IMO, ie quiet when not in boost and less restriction then a 3" catback when you are....http://www.atpturbo.com/root/releases/release091004.htm

 

That's really cool!

2 drawbacks tho:

1) I'd have to buy a whole new 2.5" Catback
2) I start boosting at 2700RPM

But still - neat-o!

I'll have to consider my options on that one.

 

Just slap on a 3" Flowmaster muffler to quiet it down.

You'll be bleeding off boost through your BOV and it won't open unless you're really on the throttle/boosting.

I'd have a 3" downpipe and then have a 3"->VES->2.5" straight pipe->2.5" catback with a $50 Hallman BC right at my shift console hole to adjust when she opens.

 

Really cool - but since I just bought this, I can't afford that short-term.
(And no, they're not my Hondas - the Hondas are moving out)


I'll consider it next year sometime.

 

That may be a good idea for SC cars but for turbo I know that you want the 3" flow all of the time. There is less pressure behind the turbo so it is able to not only is it able to spool faster but it also gets more power when spooled.

An electronic cutout would not be a bad idea though.

 

Yes, on a turbo car you'd lose a SMALL amount of spoolup, but once you hit X-psi, say 1-2psi, you'd have less back pressure then even a 3" catback. So, vacuum-2psi you would be slightly behind, but 2-10psi(peak) would be faster. Also, with a properly sized turbo, you spoolup pretty fast for a FWD on street tires, so with a bit of tweaking the gain on an EBC I doubt you'd miss the 0-2psi amount.

It's a small penalty for less noise most of the time, ie cruising, and better peak power when you want it at WOT...IMO.

 

I read something about aeromotive bring out a digital FMU at SEMA. You might want to look into that. It would be alot easier to fine tune the fuel curve with it.

 

If Im running rich with my cartech, according to my EGT's, how do I adjust so its leaning out a bit more..I have the bleeder valve all the way closed, and with the vaccum source off of the Unit, Im getting 45psi of fuel pressure at idle...so thats what im seeing as I pass 0, then while i boost all I see is Fuel pressure spike up..its not really a constant flow...it shoots around..example is when i punch it, it will shoot up to like 60 really fast...

Im seeing really low EGT's thats why im rich and my Gas milage is really rediculous...Ive gone 190 miles and im almost on quarter..I went 130 on a half tank..when im usually at 200-225 at a half mark...my car is drinking gas

-matt

 

It sucks....well it ramps up voltage to the fuel pump to increase pressure, which isn't the best for long life and the scaling of the adjusters is somewhat confusing and difficult to tune according to what I've read. A lot of 350z guys went that route, because it was the only way to go for returnless setups at the time. Now, they've all tossed them to go back to a proven pump and regulator method.

http://www.zchickz.com/prochg4.htm

 

To lower fuel pressure you can open the bleeder valve so that the rise rate is decreased, or you can back out the center screw to lower the fuel pressure at crossover from vacuum to boost.

You might remember from high school algebra the equation for a line, y = mx + b, where m is the slope of the line and b is the y intercept. The Cartech fmu allows you to control the fuel pressure, y, as a function of boost pressure x. The slope, or rise rate, m is controlled with the bleeder valve. The fuel pressure at transition from vacuum to boost is the y intercept, b, and is controlled with the center screw.