pwdbychevy

I have a Turbo City adjustable regulator on my TBI and I just installed a TPI fuel pump over the weekend and started to adjust the fuel pressure to around 20psi. I can only get the fuel pressure as far as 15psi because the regulator screw won't turn anymore. Does anyone with this regulator have the same problem? Any advice is appreciated. Thanks.

------------------

92' Camaro RS 305 TBI
Best 1/4 mile - 14.6 @ 96 mph w/NO NOS
Best 60' - 1.9 secs
Check it out
https://www.thirdgen.org/rides/index.tgo?action=view&rideid=4860

fast_broker

iTrader: (1)

That might be the max pressure that regulator physically allows, that's all. That is a lot of pressure over the 11psi OEM, about a 13% flow increase...

pwdbychevy

I can probably turn it a little more but I can't get a good grip because of where it's mounted. I'd have to take the dang TBI unit off to turn it further. I think it should be good for now. BTW is there a formula that calculates how much more HP I'm getting with a 13% increase in flow?



------------------

92' Camaro RS 305 TBI
Best 1/4 mile - 14.6 @ 96 mph w/NO NOS
Best 60' - 1.9 secs
Check it out
https://www.thirdgen.org/rides/index.tgo?action=view&rideid=4860

JPrevost

Yeah, it's called 1/4 mile trap speed. That's the only way to tune for performance. There are tools and calculations you can do to get into the ballpark figure but even they aren't useful unless you've got a scan tool, a wideband o2 sensor, exhaust gas temp sensors and some other trick stuff. Spark plugs can tell you a lot but from what I've gathered the new additives in gas makes it hard to tell.

pwdbychevy

I have the whole AutoXray scanner kit and I've heard about then wideband O2 sensors. What exactly do they do compared to a regular O2 sensor? Do you have any part numbers? I work part time at Autozone and maybe I can cross reference. Thanks.

------------------

92' Camaro RS 305 TBI
Best 1/4 mile - 14.6 @ 96 mph w/NO NOS
Best 60' - 1.9 secs
Check it out
https://www.thirdgen.org/rides/index.tgo?action=view&rideid=4860

pwdbychevy

ttt


------------------

92' Camaro RS 305 TBI
Best 1/4 mile - 14.6 @ 96 mph w/NO NOS
Best 60' - 1.9 secs
Check it out
https://www.thirdgen.org/rides/index.tgo?action=view&rideid=4860

Pablo

iTrader: (1)

you are going about this all wrong man, more fuel doesnt mean faster unless your car was lean to begin with and its highly unlikely that it is or was. That regulator is basically the same as a stock one and only allows the pressure to be adjusted that high. If you want more pressure you go to an external or you can use the GM later model tbi regulator. But like i said, you dont need it

Pablo

iTrader: (1)

i forgot to mention that you probably just made your car slower cranking the pressure so high

fast_broker

iTrader: (1)

I agree with Pablo. Plus, if you ave the AutoXray tool, you can scan the ECU yourself to see if you are rich or lean, anyway... Did you show lean before the mod? If not, not a necessary mod and will ultimately be more detrimental than beneficial.

pwdbychevy

How do you figure that it made my car slower? Actually I noticed that the car doesn't hesitate at high rpms anymore since I raised the pressure. I have an Autometer air/fuel ratio gauge and it reads rich at WOT after the pressure change. I'm assuming that's where it's supposed to be correct?


------------------

92' Camaro RS 305 TBI
Best 1/4 mile - 14.6 @ 96 mph w/NO NOS
Best 60' - 1.9 secs
Check it out
https://www.thirdgen.org/rides/index...ew&rideid=4860

[This message has been edited by pwdbychevy (edited December 05, 2001).]

Pablo

iTrader: (1)

Really now? You oughta get a job tuning race cars, you can just tell SOTP if a car got fasterwith an fp adjustment! damn you must be good

and since rich is so great, why dont we just eliminate air from the whole equation, just have the engine run on fuel only! Cap off the throttle body and go man go!

89BlwnRs

Damn Pablo, you sure do manage to get on my badside a lot, and you're not even talking to me. . .

It would seem to me that if he's modded a 305 TBI enough to run 14.6s, and assuming he's kept the stock chip and/or injectors, turning the fuel pressre up 4 psi might be noticeable in a SOTP kind of way.

Granted at WOT you want things to be a little under 14.7:1, but maybe he's that much under that a FP increase helps.

Jason

JPrevost

Sounds like what I was doing when my engine originally. I ran it rich and there was no hesitation. When I lowered the injector constant and tuned the VE tables I noticed more hesitation the closer I got to 128 BLM at cruise. This is probably because of the stock eproms pumpshot table being made for a snorkel smaller than most 4 bangers no a days. With more air "sitting" ontop the TB you would need to adjust the pumpshot table to compensate for the faster change in pressure in the manifold! For this reason I feel you should tune the pressure for a BLM around 122-124. This is usually enough to get rid of that nasty hesitation and still have good gas milage after getting into closed loop.

pwdbychevy

Look here amigo, I never said that I noticed a power improvement but I noticed that my car doesn't hesitate at high rpms ever since I raised the pressure. Don't feel intimidated buddy.

------------------

92' Camaro RS 305 TBI
Best 1/4 mile - 14.6 @ 96 mph w/NO NOS
Best 60' - 1.9 secs
Check it out
https://www.thirdgen.org/rides/index.tgo?action=view&rideid=4860