For E85, What is the limiting factor for when you have to increase fuel lines and fuel rail from OEM ?

Anyone have any detailed E85 set up ideas for 600+ whp ?

Thoughts on in tank pumps vs running a surge tank in trunk (all pumps outside tank) ?

 

Walboro 535 in-tank should be able to get you to 600whp no issue.

Are you on a return setup? (00-05?) I truly believe the limiting factor is the stock return line....that thing is like 1/8" ID....A lot of people have been able to push their setups to make 500-600whp on the stock fuel hard lines and I simply don't see how.

In my case, I was running stock lines and was having huge issues with pressure drop after a certain amount of time....I went through the whole gamut of upgrading wiring, changing fuel pumps, changing fuel rails and regulator setups, and still had issues losing fuel pressure under boost; it would build pressure to a certain point and then begin to fall off. I cut the little nubs off of both ends of the return line too as it tapers down even further; still didn't alleviate my issues.

On hot summer days I'd even notice my base fuel pressure begin to slowly fall as I drove more. My theory was that when you're running a big pump like a Walbro 450-535 on full blast all the time you end up heating up the fuel to the point where it begins to boil and you strain the pump in the process because it's trying to continuously circulate fuel through that tiny return line; eventually the fuel boils and the pump begins to cavitate. Again, just a theory, but ironically when I upgraded to PTFE lines (-8/-6), I had no issues ever again. I couldn't get my base pressure below 50-55 psi even with the regulator fully backed off because the pump was large and the return line was so small.

I can't say for certain, and this was only in my case, but I truly wouldn't recommend stock fuel lines beyond like 4-500whp....Atleast not the return line....But again, plenty of people have gotten away with it - I just find it crazy that I ran basically the exact setups others have successfully run and had nothing but issues, but when I moved to a larger return line, all of that went away instantly - got all the fuel pressure I needed after that with boost. Take my experience with a grain of salt, but it truly isn't that much of an endeavor to run new lines, nor is it really that much of an expense.

 

So I’m at 630 whp now w/ stock fuel lines and rail. 535 walbro.

So what’s the best E85 fuelset up (in tank and external) for up to 1000 whp ?

 

-10 feed and -8 return and twin 535 pumps if you really want to be able to run some fuel beyond 1000 whp. -8 feed and -6 return may suffice but you may as well bump it to the -10 feed and -8 return to be safe. cj-motorsports.com in Illinois has a really nice twin hanger. The CJ hanger and -10 feed and -8 return is the setup I run and it should be good for near 1200 whp.

 

thanks, very helpful !
assume this is in tank
* any thoughts on running a surge tank and putting the dual pumps in there (trunk) vs main tank ?
* what about fuel rail ? Any upgrades needed for what you run ?

 

Yes, in tank. I've never been a fan of an auxiliary surge tank, just keep a minimum of 1/3 tank of gas in the stock tank and you should be fine.

If you're going to upgrade to AN lines, I don't think there is a good way to use the stock fuel rail, plus it would probably be limited in flow. It would be best to get a larger fuel rail for sure. I actually have a Full Blown fuel rail I can let go since I am now going to the Kinsler intake manifold and 8 injectors, so I have no need in it any longer. Just hit me up if you're interested.

 

I have a setup for sale in the forum. I made over 900whp on it.
https://www.s2ki.com/forums/member-s...re…-1218274/

Only reason I’m selling it is because I switched to a mechanical fuel pump.