sparky0025

iTrader: (1)

The issue i'm having is that i pull vaccum at wot... KPA engine off show 101.. then until 3800rpm is 100kpa pass that it start to drop all the way to redline,
just before redline is around 92 kpa.

I also try the car with only a section off straight 4in pipe and the MAF and it doesn't change nothing on the value off the KPA same drop??

the car only made 389rwhp/377tq on a Mustang Dyno,AF is right on ,max timming is 31°
MAF curve is really smooth

Someone have an idea ?

Here my set-up

Ls1 383ci,11.4cr
TSP stage 2.5 Ls6 head 64cc
LT 1 7/8
Fast 102 intake and TB
85mm Maf
239/247 .621&.632 112lsa+2 on HUC lobe
M6
3.90gear

redtan

iTrader: (5)

It's your MAF buddy, big 102mm intake/tb/intake piping but then a 85mm OEM MAF? Yeah that will be your culprit.

Right there, you changed everything but the MAF...so it must be the MAF.

Try getting a 100mm slot style MAF or going SD and I bet you'd be right up there with 100+ kpa. Also check your air filter and make sure it's clean and not clogged.

mark21742

I'm running and recomend ditch the MAF and run an SD tune. Even with my MAF tuned in on my stock cube 346 I found I had a lot crisper throttle response running in SD.

1nasty86

iTrader: (63)

31 degrees of timing? what fuel are you using? dont know much about timing but my setup (11.5 compression) is at 28 degrees on pump gas 93

mark21742

You could probably bump your timing up a little more, but after 27-28 degrees you don't really see much of a gain and it just puts you closer to knock.....most of the time timers will max timing out to just where it wants to knock, then back it off 3-4 degrees, so that's probably why you are at 28 degrees

Cold Zero

iTrader: (1)

389 rwhp with M6 considered very low on H/C cars !! Can you log the dyno pull and watch what speed you have reach at the end of 4th.. this will indicate clutch slipping or not