hey i'm about to upgrae my stock fuel system by getting a walbro 255 fuel pump and 720cc injectors my questtions are with the 255 walbro i should be set to about 400-450 rwhp right? and i heard some things about different injectors is there any quality or performance difference between the Greddy 720's and other manufacturers injectors because the Greddy's are to expensive so i was thinking about going with another company's? also is it needed or can i go without upgradeing to a fuel pressure regulator

 

Dont cheap out here you will end spending much more in the long run when you blow it up because of a fuel problem. here is the system I am running. Thanks to RETED for the diagram. http://fc3spro.com/TECH/MODS/FUEL/pararail.jpg
His entire tech section should be read before you start any major project. It helps with planning your long term build up also.

 

i wish i new how to read that diagram...

 

4x720's or 2x550's and 2x720's?
but thats not enough injector for 450whp
http://rx7.com/cgi-local/2ndgencalc.cgi

 

What's so hard about it? ....... Fuel goes in, even split between primary and secondary injectors ....... stock, it goes through one, and then through the other .......


Anyways. Every peice you get should be Aeromotive(biased, never heard of a problem with them), especially if you want to exceed 300rwhp. I wouldn't trust a Walboro over that...Aeromotive A1000 external fuel pump for the win. And an Aeromotive fuel pressure regulator, also..

As for injectors, up to maybe 300rwhp or so, stock 550's in the primary, GReddy 720's in the secondaries. If you ever go to anything bigger then a (small) hybrid, you would then swap the 720's into the primary, and some 1000's or 1600's into the secondaries *requires modification of the fuel rail*.

But yeah, like the rich guy said . Go with the fuel parallel system, full stainless lines w/ AN fittings..Aeromotive fuel pump + pressure regulator (it has a built in pulsation dampner, so you don't need to worry about removing yours).

 

720's in the primaries would be overkill on the stock turbo, I'd think. Unless you have one of those neat downpipe-cut outs, in which case your boost would come in long before the secondaries kick in.

 

Remember, that pump is far from bolt in. In order to run that pump I had to ditch the FD pump I was running, create an entirely new fuel pump flange using AN flare bulkhead connectors, build wire passthroughs for the level sender, install an in tank filter and then begin to plumb the lines to the fuel pump. The pump also requires a rewire, new FPR, etc. Another choice would be to use the stock pump to fill a surge tank and connect the Aeromotive pump to the surge tank, install a fuel cell or sump the existing tank (unsafe to weld on). Either way it's not a bolt on.

That costs more then most people here have paid for their cars. Believe me, because I just finished setting up my fuel system. Full braided stainless, Aeromotive pump, FPR, prefilter, Mallory main filter, Russel fittings and line and some other misc. stuff. Total bill is something like $3000.

The advantage of the Walbro is that you can basically bolt it in place of the stock pump, switch FPRs and you're good to go.

 

Upgrading the primary injectors can eliminate the lean spot just before the secondaries kick in. This point has been known to pop more then one engine....The problem is that the larger primaries can cause starting problems.

 

i would like to go with the walbro it's a basic install for the most part when i said about 400-450rwhp i meant that thats what the walbro can handle right? and i am only putting the 720's in the secondary spot because i dont have enought HP to upgrade the primary's yet so are the Greddy 720's worth the extra money or can i go with another company and also when i upgrade to a walbro and 720's what would be a good FPR to use that will be good up to around 400 or more

 

A 720CC injector is a 720CC injector. Don't waste money and buy them from Greddy since you can get them from any injector shop...

400HP is about the limit of the Walbro (some people say more). You can go to dual Walbros for more power and still have a basically stock fuel system besides a regulator and injector upgrade.

 

I was told to stay away from the SX regulator. Here is alink to the guy I got my entire fuel system from http://www.shaneracing.com/sr86fuel.html

Like aaron said injectors are injectors as long as they are new and tested and from china.

sincerely,

The Rich Guy