I drew up a quick sketch of what the entire stackup should look like using the 2.5" procharger idler pulley. The washers I designed the standoff for are standard 9/16" flat washers readily available at Lowes (part# 215629, $1.04 per pack). They come in a pack of 3. You should only need one pack since you will need 1 or 2 for the procharger idler (I can't remember exactly, but I drew 2 in the sketch here.. you get the idea tho). The actual dimensions of the washers are roughly 1.165 OD, 0.595 ID, and .094ish thick. Every washer I measured was slightly different, but all of them had a larger ID than the .590 OD at the end of the standoff. The slightly different thicknesses of the washers will also help to get the one(s) that fit exactly flush with the end of the standoff that butts up to the bracket, so play around with the washers and see which fit best.
__________________ 2002 Trans Am M6, forged 9.2:1 370, F1 procharger @ 12psi, comp SC2 cam, mild ported AFR 225 heads, MAC midlengths, Borla, full suspension, 3.73 12-bolt, Mecham Hood, 19x10 Polished CCW 505A's 700ish RWHP/ 600ish RWTQ (still ironing it out)
Well Rob, looks like you are gonna be the guinea pig for testing out the prochareger 2.5" idler with those dimensions I came up with. That is, unless someone else has an extra procharger idler laying around I could use for mock up and wouldnt mind sending my way (I'll pay for shipping). Doesn't matter if the bearings are shot, I just wanted to test it for mock-up.. We were unsuccessful with finding 'Trust's old idler, so I was not able to confirm 100% that these are the right dimensions with the procharger 2.5" idler..
__________________ 2002 Trans Am M6, forged 9.2:1 370, F1 procharger @ 12psi, comp SC2 cam, mild ported AFR 225 heads, MAC midlengths, Borla, full suspension, 3.73 12-bolt, Mecham Hood, 19x10 Polished CCW 505A's 700ish RWHP/ 600ish RWTQ (still ironing it out)
Just got the call from ATI - my head unit is coming back from service next week, and I ordered up the two 2.5" idler pulleys (one to replace my worn tensioner and one for the new standoff). I'm picking up washers at Lowe's on the way home today. Hopefully an update to come soon !
Update - head unit is coming back on Wed, along with two more idler pulleys, so I got busy with washers... Usual disclaimers apply and I'm using a 6-rib setup still, FWIW.
I took the ATI idler pulley off of the tensioner, and it fits perfectly onto the standoff. I picked up the 9/16" washers (found hardened ones) and also some other smaller washers (the best fit to the ATI washer was a 12mm flat washer, which still lets the ATI pulley spin freely when pressed against the pulley center - the 9/16" ones need to be spaced out a little or they will bind against the pulley - see pics below). I will need to open up the center of the 12mm washer just a hair to get it onto the modified standoff (see the washer pic below)...
Hope this is helpful to anyone else picking out washers for this project...
Cheers,
Rob (Bad30th)
bracket and idler, showing ATI idler washer on pulley
This is great stuff. I have an SDCE kit already and just finished installing the whole kit so I don't know if I have a belt slip but I do like the idea of not removing the procharger and bracket to change the belt.
Could this work in conjunction with an SDCE kit? I would think so but I guess the belt sizes would be different.
BTW, I have a MMS crank pulley and a 4" blower pulley on, and needed a 420K6 belt. A 415K6 was just a hair short...
Really something in between would be perfect for more clearance between the two pulleys but I can't seem to find any belts in between those sizes. I have about 5/16"-3/8" clearance right now between the belts where they pass eachother when the belt is tensioned.
BTW Chad - the pulley is on the way FedEx ground...
Awesome man! I'm dynoing my car today with the 7.65/4.25 combo and a 2.5 tensioner and 3.0 idler. I'll know for sure if I am getting any belt slip on the dyno. I'll post up my results.
__________________ 2002 Trans Am M6, forged 9.2:1 370, F1 procharger @ 12psi, comp SC2 cam, mild ported AFR 225 heads, MAC midlengths, Borla, full suspension, 3.73 12-bolt, Mecham Hood, 19x10 Polished CCW 505A's 700ish RWHP/ 600ish RWTQ (still ironing it out)
^^AWSOME homie. I bet your stoked to finally be heading to the dyno. I'll keep my fingers crossed for you that everything goes smooth as butter & it lays down a damn nice number. If you get back into Tulsa early enough & it isnt raining, bring that beast by my work if ya got time.
__________________
1999 Trans Am Ws6 6-speed--12.9 @ 108.7 w/2.1 60' (street tires)(before H/C/I no new times yet) MODS: MTI Lid--Hooker Muffler--Pacesetter 1 3/4" race LT's--TSP 3" ORY--LS7 clutch kit--LS2 flywheel--224/.581 114--5.3 Bo White heads port/polished & milled .018"--Bo White port/polished TB--Patriot Gold dual spring kit--7.4 TR chromemoly pushrods
The belt slip was non-existent with this setup. It did its job well. When you are spinning the tires on the dyno and not the s/c belt, thats a step in the right direction..
glad its workin out for ya 
