E85 and stock fuel pump

TurboTPI

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What are the stock fuel pumps able to do? Im on a 3.2" pulley currently and it seems to be keeping up ok. I have a 2.8" and was wondering if I should to a fuel pump before putting it on. Has anyone ran a 2.8" on e85 and a stock pump?
 

b4black

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Too many variables to know for sure.

What I did was connect a pressure gauge to the fuel rail with a long line of tubing, then taped it the windshield. Go for a WOT blast and make sure the fuel pressure climbs with boost (the fuel pressure regulator is connected to manifold pressure).

If it climbs up great, you have enough flow. It is flattens out or drops, then you are running out of flow / volume.

And watch you knock sensor of course.
 

GTPpower

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I ran a 2.7 on the stock pump. It was losing pressure in the upper rpms. Everything was fine on a 3.0. I would think pretty hard about upgrading the pump below a 3.0.
 

TurboTPI

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So I went ahead and got a walbro 255 for my car. I got everything apart and the walbro is a lot different than the stock pump. The stock pump has two pick ups on the bottom. I got the pump from my buddy, maybe I need a W-body specific one, if there is such a thing?
 

Ron Vogel

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There’s only one line coming out of the pump though. You are probably looking at the Venturi pump...which is just there to get every last drop of gas out of the tank. You basically can just gut the bottom of the pump basket to make it work, but you won’t be able to suck the tank completely dry anymore.

It’s a good idea to watch FP as you increase boost. If the FP shelves off and the boost pressure keeps rising you aren’t going to be atomizing well at high rpms...so less benefit to e85. With smaller than a 2.8 pulley I needed to use an adjustable regulator and run a boost a pump to get enough pressure. IIRC FP was somewhere about 75psi with 19psi of boost. You may have luck by putting a diode or two inline with the alternator feedback to raise running voltage enough to juice up the pump if you don’t want to spend the money on a boost a pump
 

TurboTPI

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Thanks, I cut out the bottom of the basket. Seems to be just fine. I just need to take it for a test drive and see if it runs lean WOT.
 

TurboTPI

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Well, ive been busy this week and didn't get to really diagnose it till yesterday, but it was going lean under wot throttle with the walbro 255. I hooked up a fuel pressure gauge yesterday and its good till wot open throttle. it would jump up to 60+ psi then quickly drop to 40 before id let off. I did get the pump from a buddy that said he was pretty sure its ok, obviously it wasn't. I picked up an aeromotive stealth 340. Put it in lastnite, all good now. A/F ratio is right at 11.0:1 wot. I pick up a good amount of KR at lower speeds, but I did a pull from 60mph to 120mph and not a hint of KR. So im thinking im getting false knock at lower speeds, maybe my headers rubbing the steering rack, it is pretty close.
 

10sec

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I hate those garbage sensors. I picked up 4mph in my stock GTP when I turned them off. :rofl:
 

10sec

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My car was stock on E85 with only 19 degrees of timing and it was showing 4-5kr for the entire run. I had a hard time believing that, so I turned them off and trapped 99mph in a stock GTP :rofl: The stock pulley just didn't make enough torque to get it off the line to run in the 13's though. 14.1 is all I could get. :trump:
 

TurboTPI

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So im still having knock issues. I thought it was false from the header hitting the steering rack, so I pulled the engine forward with a ratchet strap, still showing knock. I flashed in a tune with only 10 degrees timing. Knock is gone. How much timing have any of you guys ran with e85 and no intercooler. I was running 21 degrees on my 3.2 pulley, I find it hard to believe that dropping to a 2.8 would create that much knock. I initially started at 18 degrees when I put the 2.8 on. Had knock so went straight to 10 degrees just for shits, 0 knock, went up to 12 degrees and started see slight knock again. I guess that's just what it will take
 

TurboTPI

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I should add, I have platinum AL104's in it now. I got a set of copper AL103's, we'll see if that helps. I was reading the platinum can get really hot and cause detonation, maybe that's causing my issue.
 

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