Need tuning help with my cam.

[Rhedalert]

28 degrees @ WOT, nice! You run premium fuel?

[3400-95-Modified]

Nope that was a mix of 1/4 tank 87 and about 4 gallons of 89 9.15:1 compression FTW!

[sprucegagt]

when you go to the GTP injectors youll have to go back to 43.5psi instead of the 55psi which the GTP injectors are normally rated at which makes them 36lbs.

Why?

[geldartb]

Why?

if he leaves the pressure at 55 then they wont be 33lbs anymore they will be the 36lbs like they are in the grand prix, yourr only getting the 33lbs cause you would be running them at 43.5psi

not saying he has to run them at 55 or 43.5. its his car he can do whatever he wants.

[IsaacHayes]

I think he was saying that to get them to be 33 lb/hr you run them at 43.5psi, and not the 55 that they are rated at 36#. Or you could just tune it as is at 55psi at 36#.

[SappySE107]

33# at 43 psi = 36# at 55 psi? What kind of fucked up math does that require to be true.

[3400-95-Modified]

http://witchhunter.com/injectorcalc1.php4

That calculator backs that up... close at least... 37.1lb/hr

Is that calculation wrong?

[geldartb]

33# at 43 psi = 36# at 55 psi? What kind of fucked up math does that require to be true.

exactly im failing to see where the issue was with this whole thing.

like i said its his car he can run them at whatever psi he wants to

if you do it the other way around going from 55 psi to 43.5 psi and start out with 36 as the old flow rate you get different numbers and you end up with the 33lbs at 43.5

but going from 43 to 55 you get the 37lbs

[sprucegagt]

if he leaves the pressure at 55 then they wont be 33lbs anymore they will be the 36lbs like they are in the grand prix, yourr only getting the 33lbs cause you would be running them at 43.5psi

not saying he has to run them at 55 or 43.5. its his car he can do whatever he wants.

I asked "Why", because he can run it at either pressure or something inbetween. Your not limited to just those pressures, as long as you know the corresponding flow rate. It's nothing to get worked up about.

I'm also thinking that higher pressure will get you slightly better fuel atomization. But that's my own theory.

[SappySE107]

Higher pressure does help atomization. I thought it was 33/43 * 55 = 42.2#. According to that, my old mustang injectors were 20# not 20.9. Well I guess its not as simple as I thought it was for their flow vs pressure.

[3400-95-Modified]

Yeah I'm not sure what the flow vs pressure formula is, but its an odd ball one.