Where is all my fuel going? 780cc- 50trim

[BlackHawkAWD91]

Hi, I got a couple questions. First off, I have 780cc PTE injectors,rewired-255HP walbro, 50trim PTE.
At 20-21psi duty cycles are around 90% sometimes little higher. 93 octane

Can I be flowing that much air to need that much fuel? High fuel trim is around 95%, base timing around 0. I tune with Maf trans set at 780 and SAFC, palm. Safc is plus 2 % at 4k up. knock counts <3. My greddy peak hold gets EGTs around 880c at 7k

Other question, 1st gear no matter what seems to get 7-10 knock, all other gears Nothing. Possible answers, stock fuel lines not getting fuel there fast enough? or Because of the piggy back method of tuning, Ass loads of timing. ( but why only in first?) First pulls very strong, usually breaks all four 225s going dead straight. Just dont like the knock it gets.
Other notes, I dont have a FPR, but base pressure is at 41-42.

Engine and support stuff. 50trim,FMIC,780cc,HKS 264/272 cams, 4 layer mitsu head gasket, ARP head bolts, clevite bearings on 1g big rods and 1g 20 over pistons. Tune with
palm, SAFC, and GM Mas Translater. 2g manifold ported,2.5 tubular 02 housing, 3inch ATR turbo back, Fidanza flywheel, ACT 2600, Walbro 255HP rewired,Fluidyne radiator, GreddyProfectB

Couple pictures of my car/set up
Car: http://www.dsmhorsepower.com/dsmgal...92f1a9ad8c5cf99d108550a&sort=1&cat=500&page=1

Engine: http://www.dsmhorsepower.com/dsmgal...92f1a9ad8c5cf99d108550a&sort=1&cat=500&page=1

Thanks for the help guys, im sure some of you DSM brains can help me out.

 

[DBR01]

my "guess" would be the fuel lines.....the problem you describe point's to fuel delivery and if it runs fine once the system reaches it's norm (high end 1st gear and up) then it just seems to be the lag between idle and WOT (fuel cavitation in the rail and line)....basically you have to wait until you're pump repressurizes the line....

 

[Staytuned]

I was thinking maybe fuel filter might need to be changed. It has been proven that the stock lines and stock fuel filter will supply enough fuel for 600 horses. Maybe yours is clogged.

 

[BlackHawkAWD91]

I was thinking maybe fuel filter might need to be changed. It has been proven that the stock lines and stock fuel filter will supply enough fuel for 600 horses. Maybe yours is clogged.

Well it was replaced under a year ago, but it was a napa filter. Possible issues with these not flowing as well as OEM?

Thanks for the help

 

[Staytuned]

Maybe there is problem with it but I can't imagine there is if it is only a year old though.

 

[Violater101]

You might want to look into getting an AFPR. With my car's setup, with base fuel pressure at 43psi, I'm getting around 80% DC @21-22psi (720CC inj's). Since yours is a 1g, your base FP is only 38 if i'm not mistaken. I'm not sure if 1g FPR's get overrun by a 255hp that is rewired or not. Something to think about.

 

[DBR01]

You might want to look into getting an AFPR..... I'm not sure if 1g FPR's get overrun by a 255hp that is rewired or not. Something to think about.

you can't over-run the AFPR....you can under-run the AFPR by having too little of a pump......this is not his case.....if you were not getting enough press. you will have rough idle and hugh knock....the only reason i think you should by an AFPR is because looking at your setup(injectors and turbo) you should be running close to 45 psi on fuel and the stock lines don't support that

 

[Violater101]

you can't over-run the AFPR....you can under-run the AFPR by having too little of a pump......this is not his case.....if you were not getting enough press. you will have rough idle and hugh knock....the only reason i think you should by an AFPR is because looking at your setup(injectors and turbo) you should be running close to 45 psi on fuel and the stock lines don't support that

Hrm I running the same duty cycle now as I was when I had the stock FPR, but I was having alot more knock issues with the stock FPR ..which I was told was due to the fact that the stocker was being overrun due to my bigger 255HP pump. Anyhow, good luck it getting it fixed.