I'm in the process of installing -10 feed and -8 return. The -10 is easy and straight forward using Y block but I'm a little confuse on how to return -8 on the stock hanger and keeping the function that sucks gas from the other side of the tank. Any suggestion ?

 

https://www.evolutionm.net/forums/pr...l#post11001067

 

My pump runs with the key in the on position, and I can barely here it. It's a faint whisper/whine. With the engine running, can't hear it over the exhaust...

 

Update: The car wasnt getting enough fuel pressure because the fuel pump oring was ripped... that has been my issue this whole time. now that i put a new fuel pump oring in there, the fuel pressure wont go below 55 psi. I even unscrewed the FPR all the way. So i guess now i have to drill out the siphon tube? anyone know what sized bit i should use. This whole project is getting way too over my head

 

There is an old saying, Measure Twice, Cut Once.

The details about drilling the siphon are clearly stated in the very first post in a discussion link posted in comments #15 and #26. It is well worth the 4-5 minutes it takes to read it.

Two questions:

1) What gauge wire did you use to hardwire the pump?

2) Where is the battery located (front or rear)?

 

I used a 9/64 bit if I recall correctly..

 

This setup with a single high volume 450 pump creates problems that a staged double pumper(dual 255's) avoids altogether. But to each his own.

 

The OP is having problems because he set his up wrong. If you wire the 450 like the stock pump (hi/lo voltage), and drill siphon, it works fine. Too realize it max power potential you do have to upgrade the feed and return lines, but thats the same for a twin pump setup..

 

The battery is located up front and i used 8 gauge wire.

I wanted to wire the low voltage in, but i didnt really understand how to do that. Im not a guru by any means when it comes to electrical.

 

You may as well drill the siphon. You'll want to do it anyway, and it may help, but I wouldn't expect that to cure the high pressure problem at low speeds. The bulk of that is due to the tiny OE return line being overrun by the pump. The FPR can't help because all that fuel has nowhere else to go.

You should plan on doing a little reading on the low/high voltage circuit and get some help with that, or upgrade the return line to an AN -6. Either route will get things sorted.

 

I would explain how I wired it, but it was complicated, and I forgot...lol. I had to add to relays to make it work right.

An easier way in respect to the wiring part being lass complex is to wire the pump to the stock wiring. Then, use the STM rewire kit, but only splice into the factory power wire as close as possible to the pump housing, don't sever it like the hardwire instructions say to. Then use a hobbs switch to activate the relay and provide high voltage only when its needed.

You'll still need to drill the siphon though..

 

Ted.

I was thinking of doing a little test on the syphon drill mod. O run twin 450s with the reliefs pushed in. 10AN feed and 8AN return. The car is moving some fuel for sure. I believe my syphon is drilled to 19/64s. Being that I run a lot more pressure I wonder of I could drill it out a little bigger yet and the syphon still work. Mainly because it has more flow/pressure then a typical setup. Thus allowing a better return into the tank. Follow what I am thinking?

 

Heres an update... drilled the siphon tube with a 9/64" bit and installed it and right away the fuel pressure was at 40 psi. tightened it a few times to get the pressure 42-44 psi. so with the vac line on it is around 40-41 psi. Car idles a little lean (tune prob just needs adjusted a little) but drives fine and is actually richer when i did a WOT pull. So it's good to go as far as I know

 

Just remember Dan, you want the smallest siphon orifice that allows you to keep the pressure under control. Doing that ensure that the siphon functions as designed. A tiny difference in siphon orifice size makes a large difference in flow.


It's hard to believe that worked if the pump is wired with 8 AWG, but at this point, if it works, run it.