how fast can i go with stock injectors??

[4-71/Z-28]

i wasjust curious what kind of times stock injectors are generally good for, 13's, 12's????? how fast did you go with them?

[kenmosher]

Low 12s is usually where you are pretty maxed out. There have been some people sneak into the 11s, but it's not that common.

I've gone 12.0s with heads, mild cam, stock turbo, stock intercooler, stock injectors and it was dangerously lean.

[Keller]

I managed 12.20 with stock injectors, stock turbo, stock intercooler, and a completely stock unopened motor. With recipe tweaks, of course. The car weighed ~3650. I could not get it to go any faster, and it was quite lean and I was running a lot of fuel pressure to accomplish it.

Put in a set of 36 lb./hr. Bosch 'blue top' injectors and went 12.1 almost instantly.

[stizkidz]

Keller, if you don't mind me asking, what "recipe tweaks" did you utilize to accomplish that time?

[4-71/Z-28]

if you modify youre fp regulator to be adjustable, will it still rise 1:1 ????

[Keller]

Nothing esoteric. Stuff like airbags in the rear springs, a bumper to prevent rear end windup during brake-tourquing, slicks, a hot-wired aftermarket fuel pump, adjustable FP regulator, gauges, chip, race fuel, boost at 20-21 PSI, etc. Regular T front wheels with 235/60 tires on the front - no 'pizza cutters' and tiny tires. No efforts to gut the car and throw weight overboard.

And don't use 'crushed' FP regulators. That was done in the dark ages. Use a good adjustable regulator.

[PaCemkr86]

you can also use an alky kit to compensate for having too small injectors,
i dont recomend it , but it works

[Keller]

Alcohol systems are becoming a good replacement for running race fuel.

Definitely more than one way to skin a cat.

[Survivor87]

Okay.........I'm still kind of low in the learning curve here. What is a "crushed" fuel pressure regulator?

[turbojd]

Years ago they used to take something like a socket and crush the top of the fuel pressure regulator a little at a time, this would increase fuel pressure, old style method from years ago.

[Survivor87]

Thanks for the explanation. Hadn't heard of that one before.
Steve

[kenmosher]

.... ah memories ... :shiny:

Circa 1988. my buddy Chuck and I used to put the FPRs in a vise and squeeze the top (which is basically how an adjustable pressure regulator works ... increases spring pressure on the diaphragm) using a socket and dial calipers.

I used to carry 3 or 4 squeezed to different pressures and we'd swap at the track. THANK GOODNESS for the Adjustable FRPs that came later!

[1986GN]

Can You Run 36lb Injectors With Stock Ecm And Stock Chip On A Completely Stock Engine With An Adjustable Regulator... Thanks For Any Input...

[kenmosher]

Stock ECM = yes
Stock engine = yes
AFPR = yes
Stock chip = NO ... you need a chip calibrated for the 36 lb injectors