HexenLord

Wanting to run in-tank pumps with the possibility to go E85 in the future if I want. Have a pair of Walbro 255s but have heard from a few others about issues running them with 80 lb injectors on E85 with a S475/476, as the fuel pressure needed for those injectors kills the pump's flow.

So I bought a pair of AEM 320 lph E85 pumps. They are compatible with 100% E85 or even Methanol. Same size as a Walbro 255. Initially, I could probably get away with a single pump on gasoline since I only plan on being around 550whp. I could even Y them together inside the fuel tank since they each have a built in check valve, and then not run the second one until I need the extra fuel.

My question is about trying to hold base pressure. The fuel pressure regulator I have is an Aeromotive 13129 that has -6 AN inlet/outlets. My engine is an L33 has has returnless rails so it will be mounted before the rails as a bypass regulator. I know that -6 AN will flow 1200+ whp, but these pumps together should flow more than -6 AN is capable of, so I might have issues keeping fuel pressure down to 58 PSI at idle. I have -6 AN fuel line but could easily upgrade to -8 AN line since its all braided with AN fittings anyway, but the fact of the matter is, that my FPR only has -6 AN inlet/outlet.

So what should I do? Run these 2 pumps all of the time, or put the second on a Hobbs switch at something like 8 PSI? I know that the Hobbs would keep pressure down at idle, but I'm not a fan of having the second pump just kicking on in boost.

Forcefed86

iTrader: (4)

I dont' see a reason not to run the boost activated pump personally. Depends how much driving you will do as well. Why load up the system with added pressure/heat/volts/amps when it doesn't need it? A true Hobbs switch is very reliable. I've used a ton of them and never seen one fail.

I'd run -8 to and from a true -8 regulator. Then -6 to the rail with a hobbs switch on the additional pump(s).

I like the the $1.99 3 way pneumatic air fitting installs. Have you seen them?



https://ls1tech.com/forums/fueling-i...bro-pumps.html

HexenLord

The -6 AN regulator will be plenty if the second pump isn't hitting until boost, although I'll have to get aftermarket rails and place the regulator after the rails. The injectors will be soaking up most of the fuel from the first pump when boost hits 10 psi or so. For now I'll install both pumps, put the second one on a hobbs and probably leave it off for now. Only going to need one pump until I swap turbos.

stevieturbo

Whilst it costs money....it is a pretty neat controller. Plus it does away with the need for relays etc.
Just run both off this, and ramp up flow with rpm

http://aeromotiveinc.com/products-pa...ed-controller/

HexenLord

I'm going to upgrade to -8 AN line with -6 fittings and run a Hobbs. If it becomes an issue I'll upgrade to a -8 regulator and run -8 all of the way through.

DEFYANT

Instead of the Aeromotive controller DSteck did a write-up on building your own.

http://forums.corvetteforum.com/1582689808-post1.html

stevieturbo

Yea, there are various PWM motor drivers available on egay, it's just sorting the control of the controller so to speak.

Aeromotive claim 40A for theirs, the Vette guy says only 25A though ?

For a pair of 320's though you'd need 40A at least.

DEFYANT

I believe he runs an in-tank Eliminator pump.

He actually uses a 50 amp PWM motor, if you reread the post you will see that. He does mention a 25A and that the 50A has better heat dissipation.

sschoeffler

iTrader: (24)

Hobbs switch...Made in America...Costs 13 bucks...very very simple to wire up through relays. I have a write up on it.

HexenLord

Looking into these air fittings now. Y blocks are just way too expensive for some reason. Fore makes a nice no-angle Y block for $48. Most of the Y blocks I was looking at have a 120* angle between the two inlets which is way too much to be used in my tank. The no-angle blocks are much harder to find.

My problem with the air fittings is the inlet/outlet sizes. Outlet is 3/8" for all of the ones I can find which is -6 AN in a system that I'm trying to keep -8 AN for the pumps' sake.

Racetronix makes a nice dual pump coupler.
http://www.racetronix.biz/itemdesc.a...C%2DG7&eq=&Tp=

Pumps snap right into the coupler, no hoses needed. I can't find much information about the outlet side of the coupler, but I think I might be able to drill/tap it for a 1/2" barb fitting. To me this seems like a better option that the pneumatic air fitting since it will eliminate all of the hoses and clamps from the pumps to the block.

sschoeffler

iTrader: (24)

Drill it and tap it with an NPT tap. Works great. Thats what I did. Use an -AN to NPT fitting

HexenLord

Which coupler are you talking about?

No AN fittings inside my tank btw. Just hoses/clamps. Pump to coupler and then coupler to barbed bulkhead fitting with -8 AN male on the outside of the canister.

crazyelf

iTrader: (21)

The fore y blocks are great although too large for use in the fuel pump bucket.

Forcefed86

iTrader: (4)

There is plenty of meat on the 3-way coupler to drill and tap as suggested. I go ahead and drill/tap it for an AN10 outlet, then adapt from there to your current needs. That’s the cheapest route by far, and leaves the option of adding a 3rd pump down the road. Another thing to be aware of is brass/copper don’t get along with ethanol. I’d look for an anodized alum 3 way coupler. Also don’t use brass barb fittings if you plan to run e85 in the future. SS is preferred, anodized alum at minimum IMO.

HexenLord

Here is the racetonix coupler I'm talking about:



The pumps just snap into the bottom, and its rated to hold up to 100 PSI.

I could drill the top for whatever fitting I want. Its fairly cheap, and seems easier than adding another set of hoses and clamps to the mix. I'm just not 100% sure that my pumps will snap into it because the outlet stem uses a double barbed style instead of a single.

I'll head out today and see if I can find the 3 way fitting at Lowes. I'm not sure how easy it will be to find stainless barbs there, though.

Forcefed86

iTrader: (4)

Those are pretty nice for the money. You may not be able to build a decent performance fuel system at a home improvement store. Ebay sells all the fittings you should need though.

SKINNY69

You'd save money and headaches by simply upgrading your fuel rails. Run -8 feed to rails, -6 return from rail into regulator and then -6 to tank.

What's the point of regulating the fuel pressure before the injectors? I see guys doing this all the time and I fail to see the logic.

Forcefed86

iTrader: (4)

It works without buying aftermarket rails. That’s the logic.

HexenLord

I'm planning to upgrade to a Holley Hi Ram this year. Rails will be -8 and regulator will be after the rails when the time comes. Im doing this now so I don't have to do anything later except remove the reducer fittings and hook it back up behind the rails.

Racetronix

iTrader: (2)

We do not recommend running two pumps all the time for the following reasons:

- Excessive heat put into fuel
- High power demands
- Unnecessary pump wear

Secondary pump control can be managed with a pressure switch, TPS switch, PCM etc.

DP systems perform best when run with -8 feed and -6 return Teflon lines. DO NOT USE RUBBER BRAIDED LINES.

Racetronix offers two PnP dual-pump drop in solutions:
510LPH


680LPH