throttle body and injector question!

[Zupercharged28]

quick question... 42 lb/hr fuel injectors and a 58mm throttle body too big?

[Chris 96 WS6]

Too big for what? Your setup?

Might be better asked in the Forced Induction section.

[Snigga]

Yeah, you might be runnin a little rich. With 6#s on the blower, you dont need as much extra fuel in as you think. I still use the stock injectors but I do also use an auxillary fuel pump. Im still not pumpin any 42lbs though. I had 24s in before and it was runnin pretty rich then, so i put back in the stock ones.

[Zupercharged28]

ill probably get 24s. ill be getting a 383 kit soon, so ill need them. i have an auxillary fuel pump already, with an FPM or something like that, forget the name of it. thanks guys!

[Chris 96 WS6]

Exactly how much fuel pressure do you have to run to make 24's work on a blown application?

I maxed out 24lb SVO's with my setup on stock pressure. The 30lbers push about 80% Duty Cycle at WOT at only 360rwhp. Surely a 383 with 6 lbs would need more fuel than my car....

[Snigga]

Well, when he first asked, he didnt say anything about a 383. After supercharging quite a few customer's LT1s, and seeing the dyno results, I am positive you are not required to have the 24lbs injectors. I am not saying you cant, as long as the car still gets tuned. But I am saying that with 6lbs on the blower (and not on a 383) there is no problem at all running stock injectors, as long as the car is tuned. However, I did once do a 94 Z28 that was completely stock and dynoed 285 rwhp (i guess there are freak cars out there). After putting the 6lbs on that car, we did have to switch it out to the 24s because the stockers weren't cutting it. Other than that, its like i said, stock engine with 6#s does not need bigger injectors.

[95zpro]

I just upgraded my injectors from 30#'s to 42#'s in order to eliminate my fmu and got it retuned. Didn't necessarily make more hp but the car runs a lot crisper and it seems my mpg improved.

[Snigga]

MPG improved? Someone correct me if I'm wrong please, but I thought bigger injectors would bring it down a bit. Some guidance please...

[Zupercharged28]

yea but it doesnt always pump 42 lbs or 30 lbs an hour, it only pumps what is needed, so if you were running a stock motor, you could run 30 lbs and they would still pump in the same amount of fuel as stock.. they just have the CAPACITY to pump more! thats all... 95zpro, where do you find the forged bottom end kit and how much did it run you? and yea, the 383 kit will be soon it isnt done yet... unfortunatley

[Snigga]

On a completely unrelated note, I did get the dyno tune today. 427 rwhp and 444 rwtq.

[GTP231]

On a completely unrelated note, I did get the dyno tune today. 427 rwhp and 444 rwtq.

Nice numbers:)

[Zupercharged28]

On a completely unrelated note, I did get the dyno tune today. 427 rwhp and 444 rwtq.

yea dude! very good stuff! youre rockin socks if i may say so myself... i need to get my car on the dyno after i get the pcm reprogrammed... thanks guys

[95zpro]

Let me clarify; I felt the fmu was a huge restriction in terms of the response and delivery, that was the primary reason for making the switch. Pressure on my particular setup is still controlled by the fuel pressure regulator which in conjunction with the fmu was finicky at best;had to constantly adjust for weather conditions etc. In terms of mileage I have seen a slight increase probably due to the fact of a slightly lower duty cycle of the injector ?!

[Zupercharged28]

i have an FMU installed on mine too, my fmu pumps fuel VERY quickly, theres no delay at all, very snappy and the throttle response is infact almost instant since i have the extra fuel pump and the FMU the lines are more presurized and squirts gas in quicker. you shouldnt be experiancing a delay with an FMU unless it wasnt tuned correctly

[Race4Kash]

i went with the 52mm throttle body, but when i go to a 396 block next year im putting in a 58mm tb, just depends on how soon you plan to get a bigger ci block, but as far as stock goes the 52mm is fine. and i haven't put in injectors with my set up but have put in an inline pump (not wanting to mess with the intank one as long as i can avoid it.) i will be putting in some injectors soon.

[Grims]

On a completely unrelated note, I did get the dyno tune today. 427 rwhp and 444 rwtq.

:devil: Thanks heheheh.