Seems like relay position will depend on the wiring and pump control scheme. If the relay(s) need to be near the pump, there is a cutout in the rear seat foam that is just the right size to hold two automotive relays. Its where I put mine.

The stock fuel supply line produces 15 psi of drag pressure at 500 whp worth of ethanol flow. Add that to 43 psi base pressure and say 30 lbs of boost, and you're at 88 psi of pressure at the pump. That's right at the boundary of where most fuel pump pressure relief valves start operating, so its possible to get away with stock supply lines up to 500 whp (of E85), but after that, I think -6 AN, or -8 AN if you're into overkill, is needed for the supply. With the right pump control scheme, the factory return line can work even on a 700 whp fuel system.

 

I'm thinking that the relays should mount under the car near the tank. That would allow the use of less wire overall. It's also best to have them located as near the pumps as possible to reduce voltage drop. We make harnesses with completely sealed relays and wiring so they will be fine out in the weather. I would also rather not have people drilling holes to route wires from inside the cabin to the pumps....

Andy

 

When I had a rewired 255, I mounted the relay directly to one of the fuel pump hanger mounting bolts so the relay as close the the pump as possible...

 

Where did you do this Mychailo? I put my relay on the passenger side rear.... near the footwell. The carpet pulls back and all the fuel pump OEM wiring runs through there. There was enough room to put a relay right there... alongside the OEM wiring. Then I just routed it alongside all the other OEM wiring.

OH AND THANK YOU FOR USING YOUR BRAIN AND USING O-RING -8AN fittings!!!!!! If I were you I would use -10AN o-rings and that way people could use adapter fittings to go to a -6 or -8, but you won't limit someone's creativity by making the outlet port too small.

 

My relays sit under the back seat near the front left corner. If you look at the underside of the seat, there is a little nook where they fit perfectly. I could have put them under the carpet where you mention, but I wanted the accessibility of having them right under the seat because I'm using one of the relays to switch the low voltage circuit, and I was worried that a standard automotive relay may not last long when used in that role.

 

-10 are sooooo big... Very hard to fit under the floor pan on anything we do and a -8 will get you well over about a zillion HP. I mean a zillion WHP.

Andy

 

Yeah. -6 are good for what, 900+whp on e98 before more than 10 psi pressure drop kicks in? -8 is even massive overkill.

 

hmmm your website says it cost $0.00 I tried to buy 2.

 

Fair enough. I run -8AN feed and -6AN return with a Kinsler FPR and an Ethanol sensor on the return line. I think a lot of people will be enticed by the ability to connect and OEM system to the unit and then when the time comes...be able to convert to AN CLEANLY and without any BS.

Most people buying 2 pumps are running ethanol or making an a55load of horsepower (or both) so remember who your market is.

Product looks great so far. Keep up the work.

 

What's the word on this bad mamajama?

 

We made up a batch of them and they will be with us at Sema at the end of the month. They should be available to purchase mid-November. We'll get the wiring harness and plumbing kits figured out as soon as Sema is behind us.

Andy

 

What pumps were in the unit you installed n2oiroc?

 

Walbro 262 - 400LPH gas fat-bottom pumps. We don't have his car plumbed and wired yet though.

Andy

 

Just found a new Christmas present to myself!

 

So here's a shot of an assembled unit, freshly anodized and ready to rumble. We put a few together to show off at Sema. This one is loaded up with DW300 pumps.