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FMU question, power pipe question, and pulley size question

565 views 5 replies 3 participants last post by  4 eyed mustang 
#1 ·
#1
I know that people frown on the fmu and I should get it tuned and get rid of it but for now that is not in the budget. I am doing a full rebuild on my 86engine and installing gt40 irons, cobra upper and lower, and trickflow stage 1 cam or something equivelent. I am going to be upgrading to 24 or 30 lb injectors and a matching mass air. I am only running 5-6 lbs of boost thorugh a vortec at this time. My question is do I need to change anything on the FMU or just leave it a alone?
#2
Would I gain anyting by getting a power pipe, I am new to superchargers. I just bought my car last year. Vortec was already on it.
#3
Can I change the size on my pulleys on the low boost kit from vortec to raise it higher when I need to?

thanks for any help
 
#2 ·
You will need to calibrate the FMU to match the injector for bigger than stock and a power pipe will help but with more boost it works better. And yes more boost is a pulley change away, however you dont want to overspin the compressor and create heat. You want to stay with in the limits of the blower for best results. What trim is the Vortech? Also what fuel pump are you running?
 
#4 ·
Can I just go with larger injectors without a tune and the ecu would be able to compensate for the boost. I will get a matching mass air of course. From what I understand the fmu raises the fuel pressure 1psi/1lb of boost. Is this needed because the stock injectors would not flow enough without this? So if I just go with larger injectors would I be ok without FMU?
 
#5 ·
Basically, yes. Just buy the injectors and matching MAF and forget the FMU. Then you could either go with a chip (highly recomend it) or at the very least a BTM of some sort to.

Of course, I don't know what your budget is, but you should be able to do it all for less than a grand.............even less if you surf the Classifieds on here and pick up a few used items. There are a lot of decent folks on here with good parts. Try Racing Junk too......tons of crap.
 
#6 ·
I am going to get a custom chip and tune, but not in the budget this year. Breaking the bank with the rebuild. I got a set of 24's with a mass air to match cheep. Think that will be enough without fmu.
I have Boost timing retard on car right now set at -1/lb.
 
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