MAFT Gen 2 - Anyone?

[twinturbvr4]

Ok guys, went to the track this weekend and had some fun. Was running about 18-19psi to redline, pretty good, however when I ran 3rd gear out to the line, I had almost no acceleration at the top end. Above ~ 5500RPM still at full boost my AFR starting going slightly lean (~13.5) it was upper 11s low 12s prior to 5500rpm. So in essence I could NOT break 100mph on the 1/4.. the car just wont go any faster at that higher rpm, It should be able to accelerate fully to redline I would think. I tried adding fuel in the higher rpms on the high-load setting, and a little on the mid-load setting. I also added fuel at 300gms/sec and 400gs/sec (like +15%!!!) and still nothing. Think I might be hitting the maximum output on my 450 injectors? or maybe just still some more tweaking with the GenII? It ran great all the way down the track until I got in those higher rpms in 3rd gear (it also leans out a bit in 1st and 2nd, but I dont run those out quite as hard as 3rd... I've never gone to 4th prior to the finish line) Obviously 1 option would be to go to 4th earlier and hopefully I can pick up acceleration there, but I dont want to limit my 3rd gear to 5500rpm max...

thanks for any advice!

[TurboBob]

do you have a datalog to show what your injector pulsewidths were doing? Also, when you run the injectors really hard, the ECU pulls timing.

Also you could have been knocking which would have pulled even more timing.

What kind of fuel were you running?

Otherwise, it sounds like its runnng well.

Bob

[twinturbvr4]

Na, no datalogger yet, I was running 100 octane race fuel.

think i might have been maxing out the injectors? I know I probably don't have enough info to get a definitive answer, but if you had to guess.....

thanks Bob!

[David_J]

You can check the injector duty cycle at stealth316.com. Somewhere between 5k and 6k 450cc injectors would hit the wall at 18psi.

[twinturbvr4]

Originally Posted by David_J

You can check the injector duty cycle at stealth316.com. Somewhere between 5k and 6k 450cc injectors would hit the wall at 18psi.

Oooh.. thanks for the info man! Like I said before 5500rpm she was GREAT! and I've run 20psi before having the same effect MUCH sooner than 5500rpm!

: what page did you see that on?

[Kibwe Walker]

Originally Posted by twinturbvr4

Oooh.. thanks for the info man! Like I said before 5500rpm she was GREAT! and I've run 20psi before having the same effect MUCH sooner than 5500rpm!

: what page did you see that on?

Stealth 316 - Injector Duty Cycle Calculation

and you were definitely near fuel cut with 16t's at 18 psi. You need 550's for that.

[twinturbvr4]

Thanks man, once I get my new logger I'll be better able to watch all this data. I'm planning on 680s to go along with my 16ts.. then I am hoping to push 20+ psi..

[twinturbvr4]

Hey Bob,

Lately whenever I pick up my Translator or move it around excessively the car stutters like crazy, like I'm changing major settings or something, seems to happen when the wires move around a bit. I have the wires bundled up and running under the driver side of the center console and the wideband, same thing on the passenger side.. It usually sits on the back seat until I want to grab it and change something, whenever I pick it up and bring it to the front of the car, the car sputters bad.. Maybe bad ground or something?

[TurboBob]

try unplugging and replugging the harness a few times.

Bob

[twinturbvr4]

Originally Posted by TurboBob

try unplugging and replugging the harness a few times.

Bob

I'll give it a whirl, thanks.