Ditch the FMU?
 

I just ordered a Typhoon intake for the Mustang, also getting ready to order a powerpipe. I realize that with this, I should soon be upgrading my injectors, since I haven't already done that. I am also looking at getting some new heads here pretty shortly. So here are my questions:

1.) What size injectors should I go with, preparing for the heads, and ditching the FMU?

2.) Is it a good idea to get rid of the FMU, or just change the disc out in it?

I am looking at either some Trick flow heads, or the AFR's, just depends on how much money I have at the time. I would love to jump right into the heads, but I know I need injectors, so they are my first priority. Any help is greatly appreciated!

Chris

When you take the FMU out of the car, get a good running start and heave it as far away as you can!! The FMU is just a temporary band-aid for the fuel system. Since you're upgrading the injectors, you won't need the FMU any longer. I forgot to check your sig to see if you had a bigger fuel pump but incase you odn't you'll need a 255 lph pump. Most guys prefer the Walbro GSS 340. As far as injectors go, I'd suggest 42's. 42's will give you plenty of fuel with your new heads plus they will give you some room if you want to run more boost (i.e. F150 pulley or a custom pulley).

If you don't get the heads, you should be ok with 30's or 36's without a FMU.

Actually I have had my Walbro 255lph in the car for about 8 months now. I put that in with anticipation of needing it, and I am seriously looking into getting heads, just need to sell my Bronco to afford them. I keep forgetting to order the powerpipe, so that needs to be done. Depending on how much I get for the Bronco will determine whether I can get the heads or not, because the first thing I feel I need will be injectors.
When you mentioned F-150 pulley, what did you mean by that? The crank pulley, or something else?? You have me curious now since we're both running the same blower. I had ASP build me a new blower pulley, 1/4" smaller than the standard one. I saw all of .5psi at most from it at this elevation. I swear I need to dig a mile long trench down to sea level so I can run the car!

Chris

The F150 pulley is the crank pulley off a F150. It measures 6.5" (which is a little bigger than your stock crank pulley) and usually gives 3-4 psi depending on your combo. Guys swap crank pulleys instead of the blower pulley to keep the warranty intact. As soon as that seal on the blower pulley is removed, your waranty is void.

If you want even more boost after the F150 pulley, you can call up ASP and have them make you a custom crank pulley. A guy on www.novipower.com was running a 8" ASP crank pulley and he saw 15 psi through aluminum heads and aftermarket intake !!! With the ability of ASP to make custom size crank pulley's, you can run however much boost you want (up to 15 psi) without voiding your warranty!

if you upgrade injectors , and ditch the fmu , you will need a custom burned chip or eec tuner of some kind to make it run correctly or even possibly a properly calibrated mass air sensor would get you close , and you should also get a boost sensitive fuel pressure regulator from accufab or aeromotive which are priced pretty good at www.neweraperformanceparts.com .

what year f-150 can you get the crank pulley off of and does it have to be a 302 ?

The custom chip is not a problem. I have a good friend who is a Diablo dealer, so I can get one from him for $150. Just need to find a dyno to get it tuned on. I would hope with the calibrated mass air, that the bigger injectors wouldn't be a problem. I also have the aeromotive adjustable fpr, but I don't know if its considered boost sensitive. It is the same one that is shown in the picture under the webpage link you sent. Stang_crazy, you'll have to let me know which F-150 to get the crank pulley from and I will be digging through junk yards this weekend! Thanks for all the help so far guys!

Chris

you will be all set with that fuel pressure regulator from aeromotive , but you could use some time on the dyno to get your car tuned properly . once you increase your injector size you will run rich because it is designed to run with 19 lb. injectors .

The F150 crank pulley is from a late 80's through 96 5.0 and 5.8 truck motors. It's possible to get your car running properly without a dynotune/custom chip but for safety's sake and to get the most out of your combo, I'd suggest a custom dynotune. You might also want to look into a BTM. The BTM will allow you to run more base timing because it pulls timing out as boost increases therefore reducing the chance of detonation.

As long as your MAF is calibrated for the new injectors, your car should run fine without the FMU. Just set your base timing at 10* and play with the fuel pressure. FP should be between 38 and 42 psi.