When to ditch the FMU?

[VETTKLR]

Let's see some of your DOHC supercharged combos with/without the FMU.


I just picked up a '96 Cobra with an S-Trim and it rocks. I've got the Lightning MAF, MSD DIS-4, off road h-pipe, Flowmasters
and 4.30 gears.

I'm wondering if I'm giving the injectors too much hell with the FMU with the stock Vortech pulley. I'm about to throw a powerpipe in the mix as well.

Can 42# injectors support the car without the FMU or is the FMU voodoo all hype?

 

[CKMustangCobra]

Ditch the FMU ASAP

42# injectors are good till 14psi, assuming you have good fuel pump(s) to begin with...

 

[VETTKLR]

What are the biggest injectors you can run with the factory high impedence driver?

 

[Blown306]

MSD makes 50 pounders, but I heard rumor of larger ones in the works. Don't know if it's a reality yet.

 

[Blown306]

MSD makes 50 pounders, but I heard rumor of larger ones in the works. Don't know if it's a reality yet.

I agree on the FMU, put it in the take-off pile. They are only really needed when running 19# squirters, it's simply a band-aid for undersized injectors anyway.

 

[Venomous98Cobra]

Also you may want to think about ditching that Lightening MAF. I would suggest that you go with something like Pro-M's Univer. 3" or 3.5". But go with the 42# injectors and ditch the fmu. Also are you running a chip in the car?

 

[Stylin Cobra]

Originally posted by Venomous98Cobra
Also you may want to think about ditching that Lightening MAF. I would suggest that you go with something like Pro-M's Univer. 3" or 3.5". But go with the 42# injectors and ditch the fmu. Also are you running a chip in the car?

that would be my set up exactly. 42# injectors, pro-m universal 3" MAF, paxton novi-1000 with intercooler, 255lph fuel pump, paxton inline fuel pump, custom chip.

 

[Venomous98Cobra]

Also VETTKLR if you don't already have one you might want to look into getting a fuel pressure gauge either mounted somewhere by your windshield wipers(like I have mine) or under the hood to check fuel pressure. This would be helpful when it comes time to tune. Also when you get 42# injectors get a chip if possible at the same time and have the car dyno-tuned. You don't won't to harm your engine at all.

 

[VETTKLR]

Originally posted by Venomous98Cobra
Also you may want to think about ditching that Lightening MAF. I would suggest that you go with something like Pro-M's Univer. 3" or 3.5". But go with the 42# injectors and ditch the fmu. Also are you running a chip in the car?

It's got a custom JDM tuned chip in it now.

It churned out 407.36hp and 354.45 torque

AF ratio goes pig rich from 2200-3300rpm, then settles around 12:1 @ 5000.

I'll try to scan and post the dyno sheet.

 

[VETTKLR]