Well you have me convinced that I need that now too. Better to have the car tuned with it on and hopefully not slipping at 6900RPM than decide later on I need it. Your numbers/figures still blow my mind. And you just have the 9lb pulley? Stock topgunz crank pulley and input pulley? My final test for this car would be an extended road trip because to pass the final test it needs to prove itself to be moderately reliable. A trip from Denver-Utah-SoCal and back up (maybe through AZ) would fit the bill and we should cruise GMR someday

For the little bit of money you spend, you have peace of mind. I have the 9lb pulley and the 2.85 sc pulley. There is no reason for the car to not be reliable, it drives like a stock car. It drives just as good slow as it does fast. As long as you've got a good tune, I don't see why there sould be any concern.

I did Baldy rd. on my bicycle and when I got to the village I cut over to grr and then down to gmr. I saw two cars total on grr and gmr. It was during the week. Would have been a blast in my car. Do you know gmr well?

What size is on the input shaft 8rib pulley on this kit? I measured it looks close to 3.25” but 928 sells both that and a 3.15” so well within margin of error of my measurement, and how small can we go? Are you calling the 8rib pulley the SC pulley and going for 2.85”?I imagine the limiting factor when you get too small of a pulley there you can no longer achieve proper tension with the tensioner. And since people usually go to a smaller SC pulley with a larger idler instead, does that mean this stock pulley is already nearly at tension limit being as small as can without issue?

GMR was our 7am stomping ground, we were the longboarders there early morning before it got too busy/cops. Ventured over to baldy for a bit just to even attempt it and that’s about all i could do such a steep road into hairpins

No, they go to a larger idler, not smaller. The larger idler takes up the slack.

Input shaft? Are you talking about the jackshaft on the sc side? If so, stock size is a 3.20. I got the 3.25 from 928 . The problem with changing the jackshaft pulley is that the stock one isn't a vortech style and has a different offset so if you put a vortech style (vortech or 928) then you need to add a spacer to the sc shaft in order to bring that pulley out far enough for the jackshaft and sc pulleys to line up. 928 makes a slotted spacer just for that purpose. The actual pulley on the sc I changed to a 2.85. I also had to change the idler pulley to a 3.00 in order to take up the belt slack.

That must have been a rush longboarding those roads. I couldn't even imagine doing Baldy Rd. though. It was a b!tch climbing it on my bike, there are some steep sections.

Thanks i waa going to order the spacers but thanks for the reminder would be a bummer forgetting that. Surprised you didn’t go for the 3.15” except for possible tension issues as the belt stretches.

Larger pulley on jackshaft equals more boost. The 3.15 is only a fraction smaller and the 3.25 is only a fraction bigger but I wanted to error on the bigger side.

Has to be the opposite, less input RPMs. The other 8-rib opposite of the serp belt SC pulley would get more boost by being bigger. But less belt slip at least with 3.25”. I assume that 3.20” is special order?

I believe it's just the opposite. The 9lb (2.75) pulley which is the jackshaft pulley on the serpentine side is smaller than the 8lb (3.12) pulley. If you look at the signature of "stillenz84", post at the top of the page, he's running a 9lb (which would be the jackshaft on the serpentine side), a 2.85 sc pulley and a 3.47 jackshaft (that would have to be the jackshaft on the supercharger side). That's how I read it anyway, I could be wrong.

http://www.the370z.com/forced-induct...grade-124.html

Getting back to the 3.20. I called Stillen and they tried telling me it was a vortech pulley. You can tell by the design of it that it looks nothing like a vortech pulley. It looks more to me like a magnuson pulley.

After reading your post again, the jackshaft pulley I was talking about is the one on the sc side (opposite the serpentine side jackshaft pulley). That's the one I'm replacing with a high traction. My serpentine side doesn't have any belt slip.

Yea I’m talking about the SC input pulley being smaller. Serpentine side jackshaft you want smaller for more boost (so 2.75” for 9lb vs the 3something” 8lb), bigger on blower side jackshaft (his is 3.47) and then small on actual input shaft (i guess he’s made 2.85” somehow work). Don’t try to duplicate his numbers though he’s pushing like 17psi on a built block. It amazes me that you’re pushing 586whp on 12psi and he’s barely to 700whp at 17psi. You’re sea level maybe Oklahoma is a couple thousand feet but still, crazy! He must have the sur-grip on his 2.85” though that sounds like it would be slip city otherwise I don’t know why more people would put on a smaller serp side jackshaft pulley with bigger idler pulley to take up slack when they could just replace the SC input pulley with a really small one. Guess i’ll order the 3.15 and go from there

Sounds like we're on the same page. I have a 3.47 jackshaft sc side that I sent into 928 for their sur-grip coating. When my car goes back into Seb I'll have him install it to see what psi it gives me. I don't want to duplicate what Evan has done but I would like to see a couple more psi. I'm not too concerned about too much boost as if one of the things we're going to try works then I'll be able to dump excess boost which I'll need to do when I switch to my 91 tune.

It took the force of god with that pulley puller and one large crescent wrench to get that pulley off. No way the shaft isn’t bent and/or pulley is scuffed beyond use. Also hear a bit of a whirl when I spin it that my buddy says he hasn’t heard in his, so no surprise but rebuild coming in addition to new pulley and shaft. Ceramic bearings and seals, wondering if ordering a new oil slinger could be cheap insurance, and wave washer. Hope i don’t miss any damage and blower starts tearing itself apart once i get it back on the road in case i miss something. Redon’s a bad influence ill probably be pushing 14psi on stock block before long too lol. Were at high elevation though so i could be ok but boom once i take a road trip to low elevation. Hope seb has some magic up his sleeve haha

Are you doing the super vortech upgrade or just bearings and seals? Can 928 do a complete rebuild on it or does it have to be sent to vortech for that? Hope I didn't hurt your arm twisting it so hard. :rofl2: I wonder if Seb can do a low elevation tune and set it as a switchable map?

I’ll ask him about tune maybe request your low elevation if were similar but isnt our impeller already upgraded? Hope mines still good and it doesnt need replacement so hope only bearings/seals and pulleys

The Si impeller is an upgrade from the Sci. The 928 is a billet impeller and according to them it's an upgrade to both the Sci and Si.