GTM Stage 1.5 s.c. tune issue

Dean_z34

You running stage 2 kit ? I thought 88 was max with the 1.5 85 would be over spinning

kentmo280z

I think Jinxx has a stage 2 kit

Jinxx

I'm running stage 2 kit .... both stage1 and 2 supercharger units max out at 90k... 88mm pulley put you at 90k around 7500 rpms... the 85mm is over spinning it a little at 7500 rpms (it's like 95k) ... but I normally don't redline the car ... I wanted the boost earlier in the rpm

kentmo280z

I think the pulley is the difference in my stage 1 kit compared to stage 1.5. I used an 84 mm pulley in stage 1. It pulled hard in the low rpm range. My 90mm pulls hard after 4k rpms...

Jinxx

I believe the sooner you get the boost in the rpm range the more TQ you will get ....but even with 84/85 mm pulley around 400 ish is prolly the max .......if you want more TQ you would need to go to e85 and tune for it ......or convert to a turbo kit
Still tho with what you have you should be 480-520 whp with 84mm and 350-390 TQ

kentmo280z

I just talked with another tuner , and he suggested changing the crank pulley rather than the supercharger pulley. He thought that the larger, lighter crank pulley would spin the s.c quicker, put less stress on the front of the engine and make more low end torque.

I've not seen this discussed here???

Chuck33079

I'm not sure how exactly that would make more torque. If it's the same size pulley but lighter, I would think the only difference would be on initial throttle tip-in. If it's larger, wouldn't it spin the sc less? Wouldn't it need to be a smaller pulley to spin it faster?

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2011 MB Touring-Sport-6sp-Nav/GTM TT/FI TT TDX/JTran/Kosmic/Eibach/Hotchkis/SPC/CSF/RPS/SoThatsWhereAllMyMoneyWent

kentmo280z

I just found this from 1 Slowz "the factory crank pulley is 146mm

SO an 88mm pulley would be 146/88 x 7500 x 7.5 = 93324rpm "

So a larger crank pulley appears to make the s.c. spin faster.
A) My setup 90mm pulley w/ stock crank 146 mm pulley -146/90 x 7500 rpm x 7.5 ( SC gear ratio) =91,250 rpms
B) Using a 150mm crank pulley, 90mm s.c pulley 150/90 x 7500 x 7.5 = 93,375 .
This is if my formula is correct???

THINK I'LL DISREGARD THE CRANK PULLEY IDEA.... DON'T EVEN KNOW IF DIFFERENT SIZES ARE AVAILABLE..

Wilson2608

Yes a larger crank pulley will increase the rpm of the supercharger. If your belt is slipping already though I don't know how much this will help. The reason people go with smaller supercharger pulleys instead of larger crank pulleys is because the larger crank pulley will also make everything else spin faster(alternator, ac comp) which has parasitic loss on the motor. You may net 7hp out of a larger crank pulley and 10hp out of a smaller supercharger pulley. This is my understanding someone correct me if I'm wrong

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Stillen G3, z1 Intake Manifold, Stillen Headers, Z1 HFC's, Stillen Catback. 330whp 267 ft- lbs tuned at Z1 motorsports.

kentmo280z

I ended up having Seb from Specialty Z do a ECUTEC remote tune. I reinstalled the 88mm SC pulley and did logs as he instructed. I also changed out my Bosch EV14 1000cc injectors and replaced them with ID 1050x, which was recommended by Seb.
He did a fantastic job!! The car runs much better, with more torque, from the ECUTEC remote tune than with the Uprev Dyno tune!!

All is good in the world!!

scope22

i'm running 1.5 kit with uprev and i'm at 450whp and i think 90mm pulley, i forget TQ