8 inch and my fmu

Soon to be getting an 8 inch crank pulley and pipe (maybe try the UPR?)and was just thinking about something.. I dont have a boost gauge and was wondering if i currently have underdrive pulleys then how much am i slowing down the blower? hmmm... ? also i have 24 lb injectors, 190 lph, but with a fmu calibrated to 19's, with the 8 inch will i still be running rich (the car stinks and seems to lose power up top )? I have stock heads still other then that its got the usual.. I have an adjustable reg should i turn it down some? its set at 40 right now, and i have no idea what it gets up to under boost...thanks for ANY help you can give me guys .. Dave o

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Originally Posted by Dave O

Soon to be getting an 8 inch crank pulley and pipe (maybe try the UPR?)and was just thinking about something.. I dont have a boost gauge and was wondering if i currently have underdrive pulleys then how much am i slowing down the blower? hmmm... ? also i have 24 lb injectors, 190 lph, but with a fmu calibrated to 19's, with the 8 inch will i still be running rich (the car stinks and seems to lose power up top )? I have stock heads still other then that its got the usual.. I have an adjustable reg should i turn it down some? its set at 40 right now, and i have no idea what it gets up to under boost...thanks for ANY help you can give me guys .. Dave o

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i had a question regarding this also......since the new novi 1000 has a twin belt system, can you still run an underdrive crank pulley and the 8"? or is it a self defeating operation?

Dave O, the paxton fmu is calibrated for 19lb. injectors which is an 12:1 ratio. That means when the fmu see 3 pounds of boost you have 36 additional pounds of fuel pressure. you'll need to change the disc in the fmu for your injector size. if you don't you'll be rich no matter what.

ice, the two belt blower have a seperate drive for the blower and the accersory's. You can get the accesory pulley in standard and underdrive.

haha... does all this "richness " come into play at idle? ive had this stupid idle problem forever... have taken everyones advice and nothing has worked..can i just change disks on the old fmus or do i need to buy one? what is it 8:1 ?

you can change discs, and the FMU has nothing to do with idle. The only time the FMU functions is under boost. Don't forget you'll need a bypass valve. 8:1 is the calibration for 24lb injectors. Is you MAF cailbrated correctly?

yea my mass air is calibrated and i have a by-pass valve.. it doesent idle cold i have to pedal it.. Someone told me that i couldnt chang the discs in the older style fmu's ... were they lying ?

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Originally Posted by regattacoupe

you can change discs, and the FMU has nothing to do with idle. The only time the FMU functions is under boost. Don't forget you'll need a bypass valve. 8:1 is the calibration for 24lb injectors. Is you MAF cailbrated correctly?

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it doesent idle cold i have to pedal it..

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yeah i had the same problem with my C&L before i did the blower. would cold start worth a crap. Which fmu do you have?

brent, i guess the vortech recal discs work with the paxton FMU's right? i was just recently asked this: where do i buy the discs & wich one is the 10:1? the 8:1?. i wasnt sure the vortechs were even being used in the paxton FMU's so i couldnt answer him. i was also asked if paxton started making recal discs but again wasnt sure. now curiousity is killing me, lol! do you know this info? i need to get in touch with my buddy who asked me if i can find this out.........
thanx,
-justin

I'm pretty sure you're right justin. They make a "recal" kit that comes with all of them. I don't think it is very exspensive either.

Brent,

How were you able to cure your idle when cold problem ?



Dave ...

Well I clocked it till it idled better and then it started better cold. It wasn't very noticible when I had used it with 24's. I just played with timing/fuel and idle settings to make it faster and it kinda came around when I ran on the motor. But with the 42's it started cold great(rich), when hot I had to hold the gas to the floor.