lxcoupe

iTrader: (9)

Hey guys I'm helping my brother with his Colorado that has a 5.3L L33 swapped in, we will be putting a TVS1900 that he got on it and I want to run a flex fuel setup on it. Power goals are very mild...500-550whp max. It currently makes 375whp n/a (T56 trans) so with 6-8psi on a 6-rib setup I anticipate ~500whp. Currently we are running a Walbro 255 intank inside the factory fuel pump canister, and the factory intank regulator (the canister looks somewhat similar to a 04-06 NBS truck, but smaller. It's a returnless setup.

I want to use a Walbro 450 as the primary pump, and honestly I think the 450 would support 500whp on E85 by itself but I don't like the idea of overpowering the weak returnless regulator inside the tank. And, the canister is kinda small...I'd rather run a 2nd pump externally like they do on CTS-V's. So, a Wally 450 intank, and a Wally 255 external rigged on a Hobbs switch.

Anyone have experience with drilling/tapping GM late model plastic tanks? What fittings have you used? I would do dual intanks like I did on my turbo '05 but the Colorado canister is kinda small...or I could just convert to return style and use a single 450 intank.

03sierraslt

iTrader: (22)

I ran all my stuff through the metal fuel hat not through the actual tank. Or is that what you mean?

Last Call

iTrader: (4)

I tuned a turbo truck with a big Magnafuel inline pump through one of these. I think you can add a supplemental inline in the same fashion.

https://fassride.com/shop/product/ac...p-upgrade-kit/

A single 450 on E85 is good up to about 600rwhp, so it may not be necessary.

lxcoupe

iTrader: (9)

I did the exact same on my 05 Silverado... it had a huge bucket and I could go WOT no problem with the dual pumps on E85 and fuel slosh and/or sucking the canister dry was not a problem as long as I was in 2wd. In 4WD, I had to make sure I had at least 1/2 tank of fuel, otherwise the fuel slosh would make the pumps suck air for a moment on launch.

I'm trying to make the Colorado setup a little more seamless/ a little safer. Ie. tap the rear bottom of the tank for the 2nd pump. I guess I'm just wondering if anyone has done this on a Silverado or GM truck. Because I know the CTS-V tanks are "thick wall." I'm not sure if the GM truck tanks are thick wall or standard wall.

So, canister gets a Walbro 450 (primary pump).

2nd pump (Walbro 255 inline) is run off a hobbs switch and tapped into the bottom of the tank like the CTS-V guys do it:

03sierraslt

iTrader: (22)

There is a company that makes them for the diesels, from what Ive heard they work well. I’ll try to find it.

Last Call

iTrader: (4)

Yes they do. The link in my post above has it.

lxcoupe

iTrader: (9)

Your average street car external pump isn't meant to suck fuel like that... in my years of hot rodding, plumbing a system like that on a street car has led to failed external pumps time and time again. The only reliable way to do it is to gravity feed the external pump.

03sierraslt

iTrader: (22)

Yep, didn’t even see that.

Last Call

iTrader: (4)

Yes, most inline pump cannot suck fuel, or do so for an extended period of time without failing. The pump it can be mounted pretty low which def helps, but still not perfect. People do it, so I was just sharing my experience. I think each system has it's benefits and of course, costs.

Edit!

It would help I posted the right link:
https://www.dieselpowerproducts.com/...CABEgLwsPD_BwE

smokeshow

iTrader: (16)

I haven't made any plans to change the fuel system on my LSA blown Colorado at a similar power level. Gasoline though, no E85... You can stretch the FPCM systems pretty far, especially if you play with the fuel pressure settings and pressure setting rate transitions a bit.