What fuel pressure if running 750cc injectors

[a91talonAWD]

I am running a 255llph wally, 6an fuel line, stock fuel rail, 750cc deka injectors, gm mas, MAFT, punishment racing shortroute FMIC, evo o2 hosing, 2.5 exhaust no cat/no emisson control, and a evo III big 16G.

I have the boost line running off the intake manifold teed to the wastgate and blow off valve. So not sure where the boost is at, I guess it is in the approx. 9-12psi range I will be controlling the boost once I have time to hook up the apexi electronic boost controller.

Just need to know if I should turn up the fuel pressure from the stock range of 37-38psi or leave it alone? The reason I ask this is I had to adjust the MAFT like I had 560cc injectors to keep it from falling on its face when trying to pull out. It wasn't idling for shit either till I richened the idle 3 clicks

thanks

 

[GRAVEDIGGER]

Stock range of 37-38psi should be fine. If you need a little more fuel turn it up to 40-42psi range.

 

[98GSt_4life]

i would recommend keeping the fuel pressure at the oem level unless u have another means of tuning.
and correct me if im wrong but i also believe 750cc are a bit big to compensate for with just a maft.

are u using the stock FPR? if so u might be over running it with the 255.

with all these other mods u should have a boost gauge too its not good to guess your boost especially with the e316g i personaly had a hard time trying to run that low of boost after i got an exhaust

 

[a91talonAWD]

yes I have a boost gauge just not hooked up yet...(I just got the car running and driving last weekend and only have a few hours each weekend to mess with it). I also do have a adjustable fuel pressure regulator installed...I pulled the vac. line off and set it to 38psi, just not sure if I should have it set higher do to the bigger injectors.

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[91-gsx]

yes I have a boost gauge just not hooked up yet...(I just got the car running and driving last weekend and only have a few hours each weekend to mess with it). I also do have a adjustable fuel pressure regulator installed...I pulled the vac. line off and set it to 38psi, just not sure if I should have it set higher do to the bigger injectors.

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If you have a 1g with the 1g MAFT setup, then you do not need to set the fuel pressure higher then 37.5psi. If the settings your putting into the MAFT are not working, then you might want to check to see if those injectors are really 750's... Did you buy them used or new?

 

[fuzzydoodle]

+1, you should not need to adjust fuel pressure. People are fine making lots of power, and have been for a long time on stock 1g pressure. As well as you shouldn't need any more fuel, if in fact you have 750's, they will be more than that 16g will ever need, even on E85.

I would highly suggest not T'ing you're bypass valve on the same line as you're WG.
You will want to run you're boost controller from the compressor cover to you're boost controller and then to you're WG, with nothing else, also in the shortest route possible. That will give you the best boost control and response.

Also I would suggest some better way to control those injectors than a MAF-T.

And you might have read it, or heard it many times before, or not I don't know. But I don't think you should be jumping into any of these sort of modifications, with out at least the simplest of mod's being a boost gauge. That should have been you're first modification, on the 14b, this is all assuming you didn't buy the car in its current condition.

But I see you have been a member for some time.

 

[a91talonAWD]

what do you mean by compressor cover? Also the reason I was wondering about the fuel pressure was that I am getting very low readings on my o2 sensor at idle via the palm IIIc logger 0.0v- 0.1v. The sensor is new.

Also I did have the boost gauge and all that Hooked up I just swapped engines and trans over to a different Car and I wanted to get it running before mesing with the boost levels.

 

[98GSt_4life]

i wouldnt go off the reading from your narrow band o2. and at idle it should fluctuate from rich to lean.

and i believe what he meant by the compressor cover is to run a line straight to the wastgate from the turbo, but the 16g doesnt have a spot taped into it to do this so the next best thing would be to find the closest spot to the turbo that u can tap into and run a line straight to the wastgate without T-ing it off on anything.

 

[fuzzydoodle]

Yeah, the compressor cover, what the intake hooks to.

Sometimes I have hear people driling and tapping a barbed fitting into the J pipe and running off that, which really isn't too hard a solution.

And yes, I have no doubt you're sensor is not reading right, you're running way too rich, I would suggest maybe a e-prom/keydiver, or some sort of engine management like dsm link.

The injectors are just way to big to try and manage on with the stock ECU, my bet is you will struggle with it until you seek these other options.
Which to me is not worth it.

 

[talon187]

you need a wideband no doubt about it. if your going to use the maft i would set that for your injector size and leave it alone and use a safc2 to fine tune it. or get rid of the garbage maft and get somthing better to tune. Ived used a maft myself for a few months and its junk. you will have to retune your car almsot very day due to weather change temp an what not