What's the best setting for the fuel presure regulator..

[Da Hawaiian Punch]

setting for a '91?
I have mine at 48 psi for the 75 shot nitrous.
Anybody out there have any idea?
I think the stock is some where at 40 to 42 I think.
I put a penny in the regulator to step it up some, my freind put a gauge on there and it read, 36 psi!! thats the reason for the penny trick thing.

 

[KANE]

What fuel injectors are you using - what PSI?

Remember, lower stock LB/HR injectors will use a different setting than higher, modified injectors.

I'll comb through a few articles and see what I come up with. I use standard LT4 injectors on a stock PSI fuel rail, but I went through the whole PSI and LB/HR debacle with my L98 retrofit. PSI is critical otherwise you are just missing the sweet spot.

 

[Da Hawaiian Punch]

What fuel injectors are you using - what PSI?

Remember, lower stock LB/HR injectors will use a different setting than higher, modified injectors.

I'll comb through a few articles and see what I come up with. I use standard LT4 injectors on a stock PSI fuel rail, but I went through the whole PSI and LB/HR debacle with my L98 retrofit. PSI is critical otherwise you are just missing the sweet spot.

Hmmm, I'm guessing it's the stock ones thats in there, they're a grayish color, they were in there when I bought the car from the used car lot almost 2 years ago.
Thanks for the fast reply and for looking up some info for me.

 

[Da Hawaiian Punch]

What fuel injectors are you using - what PSI?

Remember, lower stock LB/HR injectors will use a different setting than higher, modified injectors.

I'll comb through a few articles and see what I come up with. I use standard LT4 injectors on a stock PSI fuel rail, but I went through the whole PSI and LB/HR debacle with my L98 retrofit. PSI is critical otherwise you are just missing the sweet spot.

Hey Darkshark78, you didnt forget about me did yah?:L

 

[Mad-Mic]

my stock regulator was set at 45 psi thats why i elected not to go with the adjustable one yet until i do the headers so then i can be ready to tune the A/F ratio in at the dyno in a few weeks.

as the old saying goes if it ain't broke don't fix it!

but seriously bump it up to around 47-48 psi and you should be fine if your not cammed and or have heads with some good porting on your TPI unit.

i'm still running rich but not as rich as i was before i did some exhaust mods along with the k&n filter/air lid and Maf mods.

you can always put a fresh set of spark plugs in and hit a shot then pull them out and look at them to see if you are still with in the guidelines.

greyish white your lean. light brown your good. dark brown to black your rich.

 

[Da Hawaiian Punch]

my stock regulator was set at 45 psi thats why i elected not to go with the adjustable one yet until i do the headers so then i can be ready to tune the A/F ratio in at the dyno in a few weeks.

as the old saying goes if it ain't broke don't fix it!

but seriously bump it up to around 47-48 psi and you should be fine if your not cammed and or have heads with some good porting on your TPI unit.

i'm still running rich but not as rich as i was before i did some exhaust mods along with the k&n filter/air lid and Maf mods.

you can always put a fresh set of spark plugs in and hit a shot then pull them out and look at them to see if you are still with in the guidelines.

greyish white your lean. light brown your good. dark brown to black your rich.

Ok I tested mine with a gauge, and it reads my presure at 48, so I'm cool right for the nos? and how many step's colder should I go with plug's and should I gap them at 35 like the manual call's for?

 

[Mad-Mic]

couldn't help you on the plug suggestion. i gap my ac delco rapid fires at .047. gives it a longer spark for a better burn.

 

[Da Hawaiian Punch]

Thanks for the info man.

 

[redc4corvette]

standard fuel pressure for lt1 engine is factory set with vac disconected at 43.5 psi
plug gap should be at 35 with nos 100 shot 75 shot just change the plugs gap to 35 NOR RETARD.
I use ngk bp9efs or BP8EFS with 150 shot spark retard 8 degrees
1994 CORVETTE MAUI BRA.