Cartech FMU question
 

My cartech fmu is adjustable on its ratio but it does not mention in the instructinos how sensitive the adjustment is. Such as 1 turn of the knob = + or - 1 part fuel:air.

I'm just looking for a general idea of how much a turn should affect it.

Re:Cartech FMU question
 

look at your fuel pressure gauge as you boost ;D

Re:Cartech FMU question
 

That would work if I had a fuel pressure gauge...damn those things are expensive. $195 from summit :(

Re:Cartech FMU question
 

well youre gonna need one with an adjustable fmu...get the mechanical one and tape it to your windshield for tuning or something

Re:Cartech FMU question
 

Ghetto thats too ghetto ;)

Can you mount a mechanical gauge inside the car if you use high pressure fuel line? It says not to from autometer and personally I dont like the idea of fuel in the cockpit either.

Anyways autometer says you can use it with their "isolator" ATM-5280 but its discontinued apparantly.

I suppose if I absolutley have to I'll get it...not looking forward to spending that kinda money though.

Re:Cartech FMU question
 

its just to set you up initially...anyway i wouldnt out it inside, although a friend of mine did with no problems yet

Re:Cartech FMU question
 

Well how about this...

http://cgi.ebay.com/ebaymotors/ws/eB...category=46100

Its cheaper and they have excellent feedback on all of their products. Matches my dash lights being red...Besides I'd like to have one anyways to see if I have any pressure drop... lean engine go boom boom ;)

Re:Cartech FMU question
 

check out the digital gauges by vdo@ summitracing...i think they are fairly cheap too...what do you mean pressure drop

Re:Cartech FMU question
 

I'm also interested in knowing if these are any good.

Stan

Re:Cartech FMU question
 

I'll take a look at those gauges in a bit...

I mean if my fuel pump is being overworked or just decides to take a poop I'd like to know. I need to upgrade my intake pump.

Re:Cartech FMU question
 

i have the same fmu and can't seem to figure it out either, i think by turning it in you lower fuel. well at least that would make sence because you are tightening it. i don't know i am running pretty rich right now so i will mess with it tomarrow.

Re:Cartech FMU question
 

I was lucky enough to have an in car fuel pressure gauge when I used mine. You can see exactly how your adjustments affected the base and rate of rise in boost. Hell, if I had to try and street tune one without a guage, Id put the center screw in the middle of its adjustment. Its not too overly sensative and although you can change your baseline with it, it seems more to affect how it reacts when you transition into boost, and the maximum fuel pressures that will be achieved. Screwing it in 'clockwise' will raise pressures, and vice-versa.
As far as the smaller 'bleeder' valve. Leave it closed all the way. This will result in maximum rate of rise.
If you ever get ahold of a fuel pressure gauge, then you can start experimenting with settings and see how it works out. An an A6 I ended up with the baseline at stock, and the bleeder valve just slightly open to give me a 6-7psi of extra fuel pressure per lb of boost.

HTH,
Dave