dynoed the KA-turbo today, read

[klattr1]

i went to the dyno today to see what a/f ratio was like.I started off at 5.85 psi and I did not get any higher than that because I was running so lean at even 5.85 psi.I had an a/f ratio of 13.9:1 at 3900 rpm. They left off the throttle I guess after they saw that. I forgot to watch the fuel pressure while it was under boost to see if the stock fuel pressure regulator is working correctly. I will probably go back again on the rollers to find out what's going on with fuel pressure. I have a walbro 255, 72lb injectors, cobra mafs, and Jim Wolf ecu all with my motor having correct base timing, fuel pressure at idle with hose disconnected. There's so many variables.Here's the chart for the a/f ratio:



Here's the chart for the hp/torque curve at 5.7 psi and letting off at 4500 rpm:



Jim Wolf ecu's are meant to run really rich but this crap is as lean as a george foreman cooked burger.I talked to Jim Wolf and they want me to find out if the stock fpr is working correctly(adding 1 psi of fuel pressure for every lb of boost) and then they want me to send them the dyno sheets and my setup exactly. I do not know what to think right now but I cannot boost even 6 lbs of boost or I could tear my **** up over a lil amount of time.Please help me out if you have any ideas.

[Nathan]

Wow, that just hammers home the point that you should ALWAYS check your setup on the dyno, even if it's a JWT ecu. I guess I'd better budget that in for soon after the car runs! I dont know why it might be that lean, it does sound like a fpr problem too me but I guess you'll just have to check it out and see.

[fiznat]

what is stoich, like 12 something?

[Nathan]

Stoich is actually 14.7 or so, but 12.5 is generally considered to be where the best power is made reliably.

[andrave]

on a turbo especially

[fiznat]

so then he's not really running rich, per-se... not to the point where he would damage anything for running that ratio, right?

Yeah jeez... even at that ratio those numbers are pretty crappy I think... Compare that to the chart on ka24development.com, (orion's I think?). His setup was close to the same (with less fuel, even), and he had MUCH better peformance:

[Nathan]

He's running dangerously lean actually, and yeah the numbers seem on the low side. Sherlock says there's more here than just a funky ecu gone wrong.

[fiznat]

lol whoopsie daisy... its air/fuel ratio, not fuel/air ratio... hahah do'oh

[klattr1]

Wow, that just hammers home the point that you should ALWAYS check your setup on the dyno, even if it's a JWT ecu. I guess I'd better budget that in for soon after the car runs! I dont know why it might be that lean, it does sound like a fpr problem too me but I guess you'll just have to check it out and see.

Well, I only got one run in, if i had would have done another, I would have checked for it. The first time around I was nervous watching it and I wanted just to watch air fuel ratios under boost.

[machinehead]

change your fuel filter and FPR. Make sure your injectors are installed properly and not leaky

[Nathan]

Yeah, good thing you caught it though!

[klattr1]

Yeah, good thing you caught it though!

exactly, that was my whole point for going but I wish I had another run to watch fuel pressure.

[Nathan]

ifuel pressure at idle with hose disconnected.

What do you mean by this? you disconnected the hose to SET the base pressure? or you left it disconnected?

[95_240sx]

Nathan, he means so that hw can make sure the FPR makes 43.5 PSI at idle, w/o the hose there will be no vac or pressure going to it so it will be the base fuel pressure.

Ryan, IM me when you see me on next.

Rick

[klattr1]

I went to the dyno again today. They let me put it on the rollers to check the fuel pressure under boost.Well, at 1000 rpm idle the base fuel pressure was around 45 psi and under 5.7 psi it was around 50 psi. So it is working correctly. Now I gotta check mafs voltage. How do I go about doing this?

[aleph1]

Multimeter?

[Structure240sx]

now im scareda bout my car. i've been running around with jsut the fmu and 255 at 8psi hopefully everything is fine. i jsut got my jwt ecu back yesterday so now im jsut waiting for my z32 mafs the it will be dyno time for me after reading this

[klattr1]

i have someone sending me out a MDM Techtom so I can monitor throttle position sensor voltage, mafs voltage, battery voltage, injector duty cyle and such to find out irregularities. Its cool that I got friends willing to send out **** for me to use. Ill I have to do is just ship it back when im done.A guy with sr20det and jim wolf setup told me that his mafs was showing 11 volts and that the 1 volt difference caused his car to skyrocket lean at 4500 rpm(the same spot mine did). He ended redoing wiring and such and then replaced ECCS relay and it took care of the problem. He said Nissan master techs couldnt even source the problem.

[Nathan]

That's what I thought Rick, and I didn't think Klattr was dumb enough leave the vac line unhooked...just wanted to make sure

[brage]

Funny, I have been having a lean issue with my JWT setup as well. Cobra MAF, 50lb injectors, walbro 255lph @ 6.0 psi:







Those are from my TE WBo2 setup so take it with a grain of salt. I will be making a comparison between my WB setup and a dynojet soon.I'm also waiting on word from JWT.

-jeff

[WDRacing]

I just read an article about the ground wire from the MAF causeing serious problems. The solution was a new ground wire. Just a suggestion though.

WD

[brage]

I just read an article about the ground wire from the MAF causeing serious problems. The solution was a new ground wire. Just a suggestion though.

WD

I haven't done a full check of the wiring, I will definately keep this in mind. Multimeter to the rescue.

[klattr1]

pretty much checking the voltage of all my wiring is going to be key.I'll keep you updated. Im just waiting on the MDM Techtom to arrive.