My car is currently running 11 psi spiking into 13 psi, and I have yet to throw any map codes...My fuel is about -38 % across the board...Just wondering how much farther I can push it before I start throwing codes....Everyone says 10-11 psi max, but from what I hear thats at like -35% . My car is spiking to 13 psi, and no trouble...What have your guys expierences been with pushing the hack to its boost limit???????

 

I ran 12psi with 14+psi spikes with the hack, never threw a MAP code with settings at -38/37%, but I wouldn't push that hard. Anything over 11psi and you're not fueling for it.

 

actually an on-board wideband helps too...

 

There really isn't a fixed figure for max boost. All depends on what fuel pressure and size injectors u got and subsequently how much fuel you are trimming. I believe its different for everyone as no two setups are identical.

 

yeah, I am running the walbro 255 low pressure w. stock regulator so the fp went up a little compared to stock...I would like to run 14-15 psi with this setup, thats basically my reason for posting this to see if it was possible....

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by swlabhot &raquo;</TD></TR><TR><TD CLASS="quote">There really isn't a fixed figure for max boost. All depends on what fuel pressure and size injectors u got and subsequently how much fuel you are trimming. I believe its different for everyone as no two setups are identical.</TD></TR></TABLE>

Yup, it is also dependent on th CFM that the turbo runs at any certian PSI.

 

you will never actually throw a code, you just wont get anymore fuel around 11lbs. If it's rich enough, you could probably run a few more lbs to lean it out and that'll be about your limit- boosteded9 i beleive made 302hp on a hacked d-series running like 18lbs of boost with a beautiful a/f curve.

 

why would you not get anymore fuel??Like I said I am spiking to 13 psi, and I use a wideband to tune a/f looks good...It does not lean out or anything..a/f stays around 11.8-12.0...So far it is working out great...Just trying to push the envelope..

 

because once you max out the signal to your map sensor, as far as the ecu knows nothing is changing (ie 600psi looks the same as 11psi to the MAP) so the only thing adding fuel beyond the map sensor's limit is the 1:1 stock FPR. If that adds enough fuel for more boost, that I do not know. Increasing the FP a LB per LB of boost def. adds fuel, and maybe a good amount w/ 450's. So, you tell me-- Do a test w/ ur wideband and run like 14lbs purposly. See what happens to the afr. I'd love to know-- I wanna crank up the boost on mine.

 

have you dynoed your car yet? I would like to know the hp you are making and please inform us about your setup? stock intern, exhaust, etc. thanks

 

no dyno #s yet....A guesstimate would be 265-300 whp??? Set-up is bone stock b18b, ls trans, (160k miles)..Greddy 18g turbo (11psi), safc,440s,cm stage3, 225-50-15 bf street slicks(24x10) stock diff,axles,internals,intake mani,etc,etc......Best time 12.26@ 115 mph, 1.96 60 ft.....Oh yeah, full interior as well...

 

Max boost is 9.25 psi with OBD0 MAP sensor and 10.65 psi with OBD1+ MAP sensor. Where you CEL at is irrelevant; that is just a reflection of when you richen the fuel enough to return over 3 volts to the ECU.

You can (approx) figure out what percentage AFC cut will do that, too... OBD0 sensor reads up to 9.25 psi which is a max of 4.2-4.3 volts from the MAP sensor... what percent cut gives you over ~3 volts with that setup? OBD1+ reads 10.65 which is about ~4.5 volts max output... it's easier to get CEL 3 with the OBD1 sensor since it reads higher and requires less of a cut to hit the point at which the ECU CELs. If you search, you'll see 90%+ of the CEL 3 compalins were from OBD1/2 cars.

 

so as long as you keep a/f ratio safe/accurate, you can boost higher than 10.65 correct????Cause I was boosting 11 psi, with 13 psi spikes w/ no prob....11.8-12.0 a/f

 

As long as you realize your fuelling and ignition is static past what your MAP sensor can register, yes, you can boost higher. When you know the subject matter, you understand your risks and can think intelligently about how to tackle the problem.

 

thanks j....