As almost everyone is aware to replace the OEM Black Relays with either Green/Blue Relays (Blue being the newest Rev.).

I had multiple relays fail on me since I had the X for 30k miles.

Failed Relays
1x Black Relay
1x Green Relay
1x Blue Relay

Basically, replace your fuel relay every 10k miles or sooner. Think of it as maintenance.

My car started to lean out heavily after my vacation trip. I was thinking it can possibly be either my FPR going, fuel pump failing, bad gas, etc... It did not cross my mind to check the relay.

Well apparently people. BLUE RELAYS FAIL!!!

Same night, same tune. Just swapped old 10k relay with a new Blue relay.

Result:



That is 2 FULL AFR points of difference. Notice the Solid Line in the bottom graph. Boost is almost identical. This is really critical tuning any car.

I begin to detune my car in case you are wondering why there is a loss of power, since all my other posts. Since I could not figure out why the car was running lean with 1100cc injectors and they were at 90% IDC. Something was very wrong. I was driving the injectors all most all out and the car would still stay at 12's. Now I would get 10's with just a swapped relay.

Also I am sure I am close to maxing out the Walboro.

Check your relays!!!

 

Hmmm that is pretty scary. Now I'm worried about my green one!

 

yay!

relayfail

 

Suck. Thanks for the heads up.

How can you be maxing out a single walbro? On gasoline they're good for 550hp+ and I doubt you're only making 400whp dynojet on E85?

 

Fuel Pressure, I am going to test turning down the fuel pressure to help the pump flow more. I was running a 50 psi base pressure, going to try it back at the stock 38 psi to see if I can get a bit more flow out of the pump and get rid of that leaning at 6500rpm.

Also add more pulse width to the injectors.

 

550 * .7 = 385... so yeah, he could be close to maxing it out.

 

Yup, plus here is the car at its full tune.



You can see where I am probably running out of pump looking at these AFR's.

I am going to turn down my base pressure.

Old: 50psi + 27 psi = 77 psi = ~52gal/hour

New: 38psi + 27 psi = 65 psi = ~60gal/hour

If you are wondering why I was running a higher base psi it was to push the DW800cc a bit more. However, I didn't change the pressure when I put in the 1100cc. I see that I might need to turn down the pressure and help the pump flow a bit better.

But it still does not change the fact that the relay failed on me.

 

Maxing out a single walbro at 450 virtual dynojet? On pump gas?

Some added data is that the single walbro, on a Evo 10, will max out at a little over 400 whp on our Mustang dyno, but on E85....

- Bryan

 

^Same thing on dyno dynamics, I'd put that in the 450-480 region on dynojet, but I've seen them pushed farther on other platforms.


Are you running pump gas or E85? You never really clarified.

 

He has to be on E-85, because I am with a single walbro and I haven't ran out just yet, but I am close... very close.

 

I am on the 93 octane. Either, the base pressure was too high and the Walboro was struggling or the pump is slowly failing.

It shouldn't be a flow issue. 6AN Feed and 6AN Return reducing to a 4AN post regulator going into the tank.

 

That's a little confusing. It isn't 'return' at all until after the regulator, is it?

 

Ah, I see why.

I run a AN 6 to the Fuel Rail.

Then it comes out a Boomba adapter to a AN 6 line that runs into the the FPR then then a AN 4 line goes into the stock metal return line.

 

i think i may have the same issue on my green relay. can someone pinpoint the particular green relay to be changed ?

i was having issues with suspected leak and my afr's was PIG rich under boost hovering around mid 10's.

after tightening & doing a boost leak test all was ok till last nite, my af's just went nuts ! it went super lean down to 13's.

suspected wrong scaling of inj;s but doubled checked n loaded in few different settings the end result is still the same with very minor diff approx. half point of afr richer even with scaling of maf's.

will try to get a nother green relay to check out the prob.

thx for the headsup clipse.

 

You can use a fuel pump relay similar to what I use in my surge tank kit, wire it into your intank, and eliminate this issue all together. The negative side effect would be the pump running full on all the time, likely causing your idle fueling to be off. But it's a solution.