are you guys using the APS return fuel system, or something else like the AAM or CJM return kit. does anybody know what level is safe to run the stock APS system at, say 500-550, do you recommend a full return system? thanks.

 

I'm using the AAM fuel return. As for how far you can push the APS fuel system, it depends on the compression ratio of the engine. Tuan is running 12psi and 500+ on the stock block with the APS fuel system, but Zivman lowered his compression ratio and can only safely get 450whp out of the same exact fuel system. If you're building the motor, I would recommend upgrading the fuel system and injectors as well.

 

only upgrading the injectors in APS fuel system wont be enough then for a low CR engine to safely reach 500+ whp ?

 

Look at my sig....aps fuel system.....had it for 2000 miles so far.....no problems yet knock on wood...and I don't baby my car

 

Hey Tig, nice speaking with you on the phone. You could go either way on this one. With larger injectors, and around 500whp, I think the APS fuel system method is fine. At higher boost levels, you really want the pressure set after the fuel rail, rather than back by the fuel tank. The single bridge connecting the passenger side and driver side fuel rail is also a pretty big restriction. But at 500whp, I think you would be fine. Beyond that, I'd suggest the full return system.

 

From my experience and talking to Tuan at GRD, you should be able to get 500+ (maybe mid 500s) out of the APS fuel return with the right EMS and Injectors. Dropping my compression maxed out my APS injectors sooner than on a stock compression motor. If I choose to retune, I need larger injectors and a injector scalable EMS to control them. I will be keeping the APS supplied fuel system and hopefully get to 500+ whp. We tried larger injectors with the unichip, but the unichip could not conrol them properly.

You tuner will know when the fuel system is maxed out as was the situation with my car.

 

im ditching the unichip and going with the emanage ultimate and 550cc injs. think i can squeeze 550whp out with that and the aps fuel system and an 8.6:1 CR motor?

 

on a ST? Do you have cams?

 

I think there has to be some distinction made between "getting 550whp", and doing this safely and properly. With the EU, and larger injectors, I think 500whp will be easily and safely achievable. Beyond that, you are running greater risks by not using a complete return fuel system, with the pressure regulator after the rail. Can it be done...absolutely...would I recommend it...nope.

 

no, stock heads,

and yes sharif, you are right, safely is the question. im kinda in a grey zone, i dont think i will be making 550 with my setup, well the single turbo that is, without cams etc, id be very surprised if i hit 500. like it said tho, if i do the greddy tt, the aam fuel system will be used without hesitation.

also sharif, can the ultimate scale down the 550s, im gonna use the ultimate no matter what i decide, TT or ST.

 

Yes they can.

 

Hey Tig, i do not have a 500hp car but i do have some info, i am going with the T-Netics St here are my fuel system upgrades. AAM complete return fuel, system reg., fuel rails, 550 injectors.

 

You will definately need to upgrade the fuel system. I was running at about 470whp at about 9 or 10 psi and the A/F was barely in the safe zone.

I had GT Motorsports do a new fuel system for my vehicle which includes larger hard fuel feed line, a hard fuel return line, larger fuel rails, 1000cc injectors, dual walbro fuel pump and an aeromotive raising rate FPR.

BTW, I also added water/methonal injection via the Aquamist System 2d and upgraded the FCON to the latest release which now includes EGT compensation as well as other new features.