I'm too tired to research this fully. Please help.

Just got out of a shop and we had to call it quits at 355hp. Due to fuel (or lack of).

1050x, DW300 pump, e85, all braided 6-an lines, return setup with fuel lab pressure regulator at 45 psi. Running a dual rail from FM.

fuel goes from DW300 - 6-an teflon lines - Fuel Labs giant filter - GM sensor - FM rail - 1050x - return to Fuel Labs regulator - return to tank (6-an again).

Red graph is at 22psi. You can see my fuel pressure ***** the bed and heads south. Then at the very top end it is enough of a drop to see the AFR start rising. Didn't even try to get above 6000 rpm in this case.
Blue is at 18psi. 320hp and looking fine.

Tuner recommends a surge tank or larger pump.

 

BTW that is differential pressure. He is logging boost pressure and presumably subtracting it from his recorded fuel pressure.

 

stock wiring?

 

course not. relay at the pump with more than enough awg wire.

 

Well, I think it's the pump. My dw200 bit the dust after only 5000 miles, and I've read a bunch of people are having issues with the dw pumps. I bet if you throw in a Wally 450 it has no problem keeping up. There is no other reason why you shouldn't have enough fuel. Nice numbers btw.

 

Have you logged alternator voltage? Could possibly be a weak alternator dropping voltage causing that as well.

 

Turn up the base pressure. I touched up a customer's similar car (ID1050s, E85, 43.5psi fuel system) a few weeks ago and it was 78%DC at ~290whp. I'm not at all surprised you're totally out of fuel at 355hp with just 45psi of base pressure. On Acamas (ID1000s, 60psi, Walbro 400-E85), I ran 60psi of base pressure and I was able to get to 450whp at 95%DC.

If you want to keep the DW300 and maximize its capabilities, I would probably do 55psi of base pressure and keep peak boost under 25psi. That will give you 1145cc/min of capacity from the pump (assuming ~80psi max outlet pressure), and ID1050s at 55psi DFP are good for exactly that. At 55psi, you'll have enough fuel to get to the 400whp mark safely, but if you need more, you'll either need more fuel pump (Walbro 400-E85) or bigger injectors.

 

alternator is strong.

Sav has it. I just looked and I'm at 69% duty cycle at 18psi (320hp) and 83% at 22psi (355hp).

I'll put the fuel pressure up at 55psi and re-log some runs.

I want a solid 350hp with plenty of headroom (looking for the infamous tranny wrecking 400). I'll head back to the dyno once that is accomplished.

Thanks Sav!

 

Came in here to suggest the same 60ish psi. And fix your tranny wrecking number.

 

Well something Isn't truly adding up. I'm getting a pressure sensor and do some logs and report back.

 

On second look, I missed that fuel pressure log. Even with 45psi of base pressure, you should be maintaining 45psi to redline, not dropping to 32psi. There's ALSO something up with your pump or filter.

Keep in mind that 400whp corrected at 5000ft of elevation takes a lot less fuel (18-20%) than making 400whp corrected at sea level.

 

Yea the fact that the pressure takes a nose dive is an indication that its not duty cycle but a fuel flow issue. Im still going with the pump is shitting the bed early.

 

I just had a realization. I replaced the OEM pump with the DW300 and never changed the fittings on the sub-plate thing. So the 6AN has an ID of like 0.3-0.34". BUT, the little swept right angle SAE quick disconnect pipe that dives down into the fuel tank is smaller. I don't know by how much.

Do I have to weld on a replacement fuel fitting?

 

I made 453whp through OEM fuel lines and an OEM fuel rail. There's no way the OEM bulkhead fittings are the issue here.

 

good to know! Thanks Sav.

 

If I'm reading this right you put your flex sensor before the fuel rail?

Move it to the return line. After the regulator.

 

I doubt it:
Fore Innovations: Restrictive Flex Fuel Sensor?

 

Okay well then get a new fuel pump.

 

I would seriously consider moving the sensor to the return if it is not already there. I have personaally seen one of these get plugged by a foriegn object. On that install, the sensor was on the return, so the result was an extreme rich (safe) condition. If the sensor had been on the source line, it most likely would have been catastrophic.

 

Have you ever looked down the barrel of a GM flex fuel sensor? It's nearly wide open. If it gets plugged with something, you're either running absolutely no form of fuel filtration whatsoever, or your injectors and FPR will shortly be so fucked that it won't matter anyway.

If you aren't making a thousand horsepower, there is absolutely no reason to run the sensor in the return line. Running it in the feed line immediately before the injectors gives the most accurate data possible to the ECU for ethanol trims, especially during transition between E85 and gasoline.