Topgunz - air to air upgrade

turtle64b

I've put belt dressing on both sides of both new belts and I have the TBatt pulley and the Si impeller and the 9lb pulley. I only make 8.5spsi @ 7k RPM on the street (3rd gear pulls)... Seb made almost 10psi on the stock 8lb pulley on someone else's car on a dyno (generally done in 5th gear).

I don't say that to knock anybody or anything, but to give you a data point if your street data looks different from your dyno data.

I haven't been able to get on a dyno yet to see pressure there since I went to the 9lb pulley.

The thing I have yet to do is use a thermal imager on the pulleys to see if any of them are heating up more than the others because of the frictional heat from belt slip (if that is the issue).

If you have any questions with what I've done to ensure that the issue is not with the engine, I'll be happy to talk to you about it. I can also trade logs with you if you'd like just for comparison to see if we're seeing proportional and similar performance.

Out of curiosity, if you don't mind, do you have the 928 bearings?

redondoaveb

I called Vortech and the tech guy said most likely belt slippage and if I have slippage there should be belt dust and suggests high traction pulleys.

I checked and I have a lot of belt dust below/around the jackshaft pulley in the sc side so I'm definitely getting belt slippage. There is no belt dust around the sc pulley but the 2.85 I bought is a high traction. No belt dust anywhere on the serpentine side. I went ahead and ordered the high traction jackshaft pulley. Wondering if I should go ahead and change the sc belt also?

I don't have the 928 bearings and I know the bearings could be living on borrowed time.

Also, all of my logs were done on the dyno in SZ shop. I haven't done any data logging on the street. I made a little over 10psi with Si sc and 9lb pulley on the dyno.

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Fast Intentions "Stage Seb" twin turbo #098- Specialty Z/Tial-Xonarotor/CJM/Ecutek/HKS/KW/SPL/Hotchkis/Rohana/Toyo
750whp/700ft.lbs

turtle64b

Can you guys give the part numbers or link for the pulleys that you picked up from Vortech? Or let me know how you communicated your needs to Vortech. I want to change up my pulleys now for the high traction design given my lower-than-expected boost issue to see if that might help. The CRC dressing got me .3 more psi haha

I saw this one, Part# 2A038, on the Vortech website. It is the same part number for the "normal" 8-rib supercharger drive pulley and the "high-traction" pulleys...

The high traction category doesn't have a 3.4 option... Otherwise, I'd go back to the 8lb serp side and do the 3.4-3.0 jackshaft-SC on the SC side like Topz

I was thinking of keeping the 9lb serp side and ordering two 3.15 (is this what y'all are calling the 3.2?) high traction to replace the SC side.

And to answer the question, you might as well replace the belt, knowing that you've worn the belt a bit and having everything apart.

redondoaveb

I'm replacing my jackshaft pulley with the 2A038 high traction 3.15 as they don't make a 3.20. I don't know what manufacturer the stock jackshaft pulley is but it's not a Vortech. Also, if you change your jackshaft pulley to the Vortech, you need to add a spacer to the sc shaft as the Vortech pulley is a different offset than the stock 3.20. 928 Motorsports makes a high traction 3.25 that looks pretty interesting but it's $180.00.

I already have a new belt ordered.

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Fast Intentions "Stage Seb" twin turbo #098- Specialty Z/Tial-Xonarotor/CJM/Ecutek/HKS/KW/SPL/Hotchkis/Rohana/Toyo
750whp/700ft.lbs

turtle64b

If I get a pair and replace both the jackshaft and the SC pulleys with the 3.15 (or smaller) High Traction from Vortech, won't the offsets match?

redondoaveb

Nope. I installed a Vortech 2.85 sc pulley and it lines up fine with the stock jackshaft pulley. When I change my jackshaft to the high traction Vortech I'll have to add the spacer. FYI, 928 Motorsports carries the spacer, it may need to cut to length. Also, you'll have to use a longer bolt on the Vortech jackshaft pulley as it's wider than the stock pulley.

Stillen didn't use a Vortech pulley for the jackshaft, it looks like a Magnuson but I'm not positive.

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Fast Intentions "Stage Seb" twin turbo #098- Specialty Z/Tial-Xonarotor/CJM/Ecutek/HKS/KW/SPL/Hotchkis/Rohana/Toyo
750whp/700ft.lbs

turtle64b

Interesting...

Thanks for the info!!!

I'm not sure my tranny is ready for that much boost haha. Or me ready to spin the Vortech bearings that fast haha. But since I'm swapping out the pulleys anyways, I might go with the 3.15 jackshaft and maybe the 3.0 SC...

Per the Vortech calculator, I'm at 55.6k RPM now (with the serp-side 9lb pulley). Bumping down to the 3.0 while keeping the 3.15 ~stock size jackshaft would put me at ~58.4. Strongly debating stepping down the size since it'll keep me in the limits of the tranny.

If I had the 928 Supervortech upgrade, I'd go 3.47 jackshaft and 2.85 SC, which would spin it ~68k!

Did you just source the longer bolt from Lowe's or similar? Did you increase the SC-side idler?

Thanks again!!