why are FMU's so bad?
 

here's the thing. I bought an FMU off of ebay...it's black and it looks identical to the blue vortech 12:1. same saze, same fittings and brackets. I decided not to hookup my MBC seeing that the wastegate is already set to 8 psi. I am running 8psi intercooled, MSD 6 series, ghetto "spoon-spec" chip (which miraculously works considering i bought it on ebay) and using the mystery FMU, and I have been running well...I look on the air/fuel gauge and I am running HELLA RICH, like to the second last bar! that's...that's a good thing! but i am so confused. a lot of people here say it is not good to use the fmu past 6 psi.

well i did. ???

on a d15b7. ???

and i am still running strong...so can anyone tell me some of their FMU stories good or bad?

thanks,
chris

Re:why are FMU's so bad?
 

Its more of a tuning thing. You have no way of tuning anything. The FMU units are not reliable either. Sometimes it might raise the pressure 120 psi at 10 pounds of boost and sometimes it might raise it 150 psi. Also, running super rich is robbing horspower from you. You are crazy for running 10 psi with an FMU. Good luck with it. I hope it goes well. That A/F gauge is really not all that accurate. Keep a good eye on your EGT and make sure it has plenty of fuel. Are you sure it is a 12:1 disk? How do you know? ???
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Re:why are FMU's so bad?
 

im pretty sure that spoon chip advances your timing.. be careful.

Re:why are FMU's so bad?
 

FMU's raise the fuel pressure, the more boost the more pressure. Your injectors are not designed to handle higher fuel pressures so the more pressure you run the higher the chance of an injector falure.

With a FMU i would not boost above 6 psi.

Pieter

Re:why are FMU's so bad?
 

Why not add bigger injectors and a different FMU disk ?

Re:why are FMU's so bad?
 

because your stock ECU wont idle larger injectors... ::)

it's been proven. honda fuel pumps flow the most fuel at the STOCK fuel pressure. you start cranking up the fuel pressure, and you lose flow from the pump straining, and you can lose a good spray pattern from the injectors. FMU's are a cheap ass way to run a low boost setup. i also think you are nuts for running over 6 psi w/ that FMU.

Re:why are FMU's so bad?
 

okay...

the ECU was chipped to add more fuel to the mixture...i don't think my FMU is 12:1, maybe it's the 8:1 or 5.6:1...i am not sure...all i know is that it works...

if the chip i added does advance my timing, how do i retard the timing?

I only hit 8psi for a split second before the car shifts...because it is automatic i rarely hit 8psi. but if ever i do, the gauges tell me i am okay.

thanks again for all the help and info. I just don't want the car blowing up.

where to start? fuel isssue
 

I have a fpr, fmu, 255lph pump, greddy fcu, bosch turbo injectors/resistor box, I want to run 8 psi on my b16 that has a port and polished head,complete msd ign., t3 turbo, obx mani., dsm ic, jun ebay chip, but I dont know where to start with the fuel setup, I dont know the flow rate of the injectors,they are same as the porche, the fcu, is program for 320cc injectors, I call greddy today and the said, the fcu can be reprogramed, but they dont do it. long post? I can keep going, so lets break it down and give help so I can give more info...

Re:why are FMU's so bad?
 

I have heard of people using the "Blue box" and having good luck with it. I bought one and never installed it in favor of an AFC. I wanted to go Hondata, but that just wasn't practical for me considering I would have to drive 300+ miles to tune it. I would suggest to you the AFC hack. If you are planning on running 10 psi or less the AFC is perfect. Buy an AFC and sell that FMU, Greddy blue box and that should pay for the AFC. :)
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