si_mekanik

My setup:
99 Si stock b16a2
T3 turbo, 8.5-9psi (Joe P MBC) Intercooled, Tial wastegate.
VAFC hack DSM 450cc injectors
Settings: -38% from 1-4K RPM and 4K-8K -37%

So I ran my first two runs and they were successful. Well I was gunning for a 13.9, so I thought i'd shift at roughly 8200 and take it a wee bit after redline. Mind you i've NEVER bounced off the rev limited since i owned the car (over 2 years). But as I was near the end of the 1/4 mile, i was in i think 3rd or 4th gear, and i bounced off it....fuel cut off, and on the way down at 7K RPMs the motor felt like it cut off again.... hhmm...

SO i decided to give the car one more whirl. I went down the 1/4 mile again, but toward the end I can't remember if it was 3rd or 4th gear, but the motor seemed to "cutout" at 7K RPM....right in the same spot as the first time. So I coasted the rest of the way. But when I first took off at the launch and the shift from 2nd to 3rd, I took it up to 8K no problem.

I checked my plugs, and they look pretty good actually. Althought plug number 3 was not snug in the cylinder. I am throwing code 41, which could be due to my primary o2 failing maybe. Going to a tuner next week. Car runs great, but im not sure what will happen if i try to take it up to 8 grand again

To give you idea.... with a shitty 60ft launch, I ran a 14.209@103.66MPH, and my next run where I bounced off the limited i got 14.140@94.41 MPH.... my last run when i decided to give it one more whirl (where my fuel cut off at 7K RPM at the end of 3rd gear) I got a 14.788@84.77MPH



So anyone know what caused my spark to miss? Maybe it was that 3rd plug that wasn't that tight down possibly. Or maybe my ECU decided to cut things off because of code 41 for whatever reason...??

HMT-Admin

The 103 trap is good for 13's.. just gotta get the ****** to hook up

Tom-Guy

I'm wary of the 450cc being able to keep up with a B16. Your stutter may be due to lack of fuel. Hook a wideband up, datalog the stock O2 input, do something.

If uncertain, try upping your fuel pressure a few psi from stock for more flow, and retune your idle and such with the AFC. Some people drop money on FPRs, but I'd just crush the stock regulator a tad in a vise until I got the pressure I wanted. About 47-50 psi should do you. :>

Todd

I agree with Joseph.. Especially with the hack taking 38% off the injectors. Sounds like not enough fuel.

si_mekanik

I do have a B & M riser.....fuel pressure is at around 42psi idle, and it goes up to 50psi when on full throttle. I'll bump it up a few psi.


thanks,
kevin

BigJ

Your running way to lean at high rpms, your going to kill your engine, right now I have -33% from vtec up on my del sol and it runs like a champ