Raising the boost -- think it'll go lean?

[Dave]

Tomorrow Ill be installing a cut out raiser and set the cut out point to 15.5psi. I don't have an A/F gauge or anything to monitor it, I'm broke as hell yet I have a cut out raiser laying around. lol Ill buy an A/F gauge here in a few days, but Gus Mahon said he ran 15.5 psi safely intercooled.

I have just a TII intercooler mounted down low and up front, a cool air intake, and a Garrett turbo. I think it should be kept pretty kool. Should I try squeezing my FPR a little to get 8 or 9% more fuel just to be safe??

[Heavytank2]

I dunno... I would look into adding a coldstart injector...

[Stevien1]

Don't do it unless you have a way to monitor a/f or EGT. Even a DVOM tapped into the O2 signal line is good enough. I wouldn't run anything under .90v at WOT. Every car is different, so you may or may not be able to run the extra boost without additional fuel mods.

-Chuck James

[Marcus86GLHS]

DAVE the easiest way to hurt your engine is to begin making boost changes w/o monitoring the effect on a/f ratios....dont do it until you have a gauge....we're talking 20 bucks here.

remember that a proper a/f ratio not only gives better reliability, but, by keeping it not-too-rich (ie: 11.5 to 12.5 to 1 as opposed to a rich 10 to 1) you will pick up some power.

[Dave]

Okay well ALS (Al Shiplet) has one of those digital computers that can read out everything, I don't know what all it reads but I know one of those is MAP voltage. WHOOHOO! So I might just crush a FPR real quick and bring it with me just incase it's too lean. Ill be going up there today around 3pm and Ill let everybody know.

Any advice on crushing the regulator?? It's a TI of course. Gus's site doesnt explain it to well to me, so Im a little confused...

My base timing is at 12*, is that a good base to start with when playing with A/F's? Or should I lower it to 10* then slowly raise it along with the boost???

Last thing, how accurate is the MAP voltage? If it's about .87V it's fine, right? But is that real accurate??? I remember my brother's 16bar A/F gauge was always dead rich at WOT and he had a TI running 14psi non-intercooled, ended up destroying #2 ring lands.

[BUBBA]

Quote:

Originally Posted by Dave Okay well ALS (Al Shiplet) has one of those digital computers that can read out everything, I don't know what all it reads but I know one of those is MAP voltage. WHOOHOO! So I might just crush a FPR real quick and bring it with me just incase it's too lean. Ill be going up there today around 3pm and Ill let everybody know. Any advice on crushing the regulator?? It's a TI of course. Gus's site doesnt explain it to well to me, so Im a little confused... My base timing is at 12*, is that a good base to start with when playing with A/F's? Or should I lower it to 10* then slowly raise it along with the boost??? Last thing, how accurate is the MAP voltage? If it's about .87V it's fine, right? But is that real accurate??? I remember my brother's 16bar A/F gauge was always dead rich at WOT and he had a TI running 14psi non-intercooled, ended up destroying #2 ring lands.

I think you're talking about O2 voltage, correct? Dude, you should just come get the air/fuel gauge I have. I'm not gonna use it... Or at the very least, hook up a multimeter to your O2 sensor to read out the voltage. I always had mine around 1.0 volts to be perfectly safe for the sake of loosing a few HP.

Christian J. Grest

[mo' parts]

get the a/f gauge at least before raising it that high.
when i first got my motor together and broke in i was wanting to run more boost but didnt have the cal.
i have a/f, egt so i put a small bleed on the map line, just enough that it would cut out at about 15.5-16. it did spike to 17-18 once or twice, but i didnt stay in it long.
anyway, my egt never got above 1500-1525 at about 16 psi, and the a/f was still lighting about 3-4 green bars on the auto-meter
i had a walbro 255 in the tank, stock injectors, small npr i/c, and stock electronics. i did however have a afpr, which i raised the base to 60-65 psi for safety before i even tried anything. also im thinking the t4 comp. cover might have been putting out lower discharge temps, which wouldnt require as much fuel. that and i run forged pistons for that extra saftey margin.
i bet i could have ran 16 psi safely with that set-up. but didnt want to chance the longevity.
just be careful, raise it slowly and at least get the a/f gauge from bubba. you should be fine under 16 psi.
i havent read much on crushing the fpr, but it should get you a few more psi, which would most certainly help.
good luck

[tryingbe]

Quote:

Originally Posted by Dave Tomorrow Ill be installing a cut out raiser and set the cut out point to 15.5psi. I don't have an A/F gauge or anything to monitor it, I'm broke as hell yet I have a cut out raiser laying around. lol Ill buy an A/F gauge here in a few days, but Gus Mahon said he ran 15.5 psi safely intercooled. I have just a TII intercooler mounted down low and up front, a cool air intake, and a Garrett turbo. I think it should be kept pretty kool. Should I try squeezing my FPR a little to get 8 or 9% more fuel just to be safe??

DO IT, I want to see some melted pistons and you getting MORE broke!

[Dave]

Quote:

Originally Posted by tryingbe DO IT, I want to see some melted pistons and you getting MORE broke!

Running 15psi for the past 3 days and beating the hell out of it... still going strong, just it cuts out at around 5,000 RPMs. damnit.

Even if I do blow it up, Im replacing the pistons with cast this winter, might as well blow it up!