RTEK 1.8, 4 x 750cc injectors, Apexi Neo MAXED - STILL LEAN UNDER WOT
 

So... I'm running an RTEK 1.8, 4 x 750cc injectors and my Neo MAXED, but, still lean over 50% throttle. (By lean I mean 13:1 AFRs at WOT)

It will hold mid-11s AFR up until than...

What you guys think? Time for larger secondary injectors?

Could it be that I'm using a stock s5 turbo?

For engine / exhaust info please see my signature below.

Thanks for your help guys,
-Chris

Are you using a T2 AFM?

If your running the stock turbo there is no way that you could be maxing 4 750cc injectors. It simply can't flow that much air (unless of course its a hi flow)

Yes.. It's running a s5 turbo MAF

I know my turbo has been ported as it holds boost well throughout rpm range with 3" exhaust behind it and 2.5" intercooler piping to a fmic ... I don't think a "stock" turbo could do that.... All third or forth high load pulls

I ran stock turbo, 14psi with 550/750 and did NOT max out the injectors so no way in hell that is the issue.

first thing that comes to mind is loss of fuel pressure, could be caused by:
Bad fuelpump
Clogged fuel filter
Something wrong with the FPR

I had a clogged filter once, as soon as boost got over 8psi it could not flow enough and would run very lean

Fuel filter recomendation? I'm drawing through a Summit canister fuel filter now which should flow double stock

Pretty much any filter will do, as long as the connections have the same diameter, i believe somewhere around 8mm

I ran stock before this one, and would prefer it.
but i had these issues 1 day before a race so i had to go to a local parts store and had to pick just a random filter with the right connections.
Flows more then enough for my 400hp.

Filter is the cheapest and fastest option to test, and if thats not it, a new filter never hurt anyone! (Some people forget they should be changed every few years!)

Yeah... But i changed my filter cartridge fairly recently

This filter BEFORE my IN-LINE Walbro 255 pump

http://www.summitracing.com/parts/sum-g1507

This is not the right filter..

Flow is enough, but it is stated as "Up to 15psi pressure", so that would mean that this is a filter for carb'ed engines, not fuel injected

Also, if you look at the applications list, it shows that this is for carburettor only

http://m.summitracing.com/parts/sum-g1507/application/

^ Bingo. Change that out very quickly.

I hope you're using high pressure fuel injection rated fuel hose.

Yes.. Fuel injection hose.. The filter is BEFORE my fuel pump and therefor has NO pressure going through it.
I don't see how this could be an issue... Grrr

Guess i could try removing it and istalling stock Turbo2 filter AFTER pump ??

Even though it is before, it could still be restricting your flow.

Wait.. what?

You mounted the filter inside the tank or what?

Gas tank to canister filter to INLINE pump

You had me fooled by the fact that you own a FC, as this is the 2nd gen section...
Adding the fact that you own a 1st gen with a totally different fuel setup would have helped in regards to solving the problem..

I think the gravity feed to that pump is insufficient..
You may need an in-tank walbro, with a normal fuel filter to keep up with your fuel demands

I'm not going to swap gas tanks on a "i think"... The pump is the in-line version and should flow exactly as the in-tank version.
The ONLY advice i've gained here so far is it MAY be my fuel filter and my turbo SHOULDN'T be able to max out 4 x 750cc injectors.... Everyone has read the engine DOES have a large streetport right?

^+1 on the fuel filter restriction. Try a fuel flow volume test to see what the system can physically supply. What fuel pressure are you running and how is it regulated?

If that checks out, I'd suspect one of your secondary injectors isn't wired correctly.

As for your setup:
Your injectors flow enough fuel for a stock S5 turbo.
Fuel pump is sufficient.
Streetport doesn't matter. It can't be big enough to affect it this much.

S5 fuel rails... Using stock rail-mounted regulator

Ok... I'll try eliminating the canister filter BEFORE the pump and install a stock Turbo2 filter AFTER the pump this afternoon

How sure are you that you have 720 injectors?

For got to mention...I'm running rtek 1.8 with 720s,extended street port, stock turbo, and all supporting mods. My car runs RICH!! But on rteks website it states it you don't run 720 with the 1.8 it would lean out and cause engine damage. Which is why I asked if you were sure about your injector size.

Had them cleaned and cc'ed about a month and a half ago... Lol.. My injectors are awesome.. I watched the test... The RC injectors have a beautiful conical atomization.. Way more atomization than the Injector Dynamics... They just have three large jets of fuel.. Lol

Damn...if youre sure you have 720s then I'm not sure what could be wrong. Have you tried calling rtek? You should start were everyone else said...the fuel filter. Lol what pump are you running?

Oops nevermind...i just saw you already answred my question. lol