i bought a vortech fmu from someone and he told me that it's rated at 12:1. is there a way for me to know what's the real rating is, whether it's a 5:1, 8:1 or really a 12:1? by the way, the color of the fmu is black and not like the current fmu which is blue, i don't know if that mean anything.

 

anyone? c'mon guys....

 

you need to open up the fmu to see which calibration disk it has.

 

You have to measure the disc inside.

 

is it written on the disc or do i have to measure it? if i have to measure it, what size disc would i expect for a 12:1?

 

If its a 12:1 it will just be a HUGE disk, it will take up ALL the space inside the FMU when you open it.... back when I had my FMU on I thought it was a 12:1 till one day I opened it up and found out it was a 10:1 (explained my running lean) so I swapped in the big 12:1 and things went smoother.... check out the pics I have in classifieds where I'm selling my fmu it shows all the discs cept the 12:1 just look at the biggest disc in the pick and the 12:1 is bigger then that, get the idea?

 

You have to measure it. Measure yours and I'll tell you what you got.

 

the disc inside measures at 2 1/4" diameter. is this a 12:1 or what?

 

Archive this one:

12:1 2.71"
10:1 2.46"
8:1 2.22"
6:1 1.85"
4:1 In the car and dont wanna measure it...its smaller though.

 

damn. that means what i have is an 8:1. will that be enough for boosting at 7psi? thanks man.

 

dayum now i gotta measeure mines to see waht i have too....good info