Upper pulley VS lower pulley VS doing both

dfxrte · 03-17-2023, 08:00 AM

hi all,

wondering if there is any benefit or just preference to swap one over the other.

I have my upper pulley and belt swapped out and planning to do the lower, but it seems so many ppl either choose to do lower or upper and not always both (unless heavily modified).

Is it too risky to do both or something?

For context, I am very mildly modified with just headers, intake, upper pulley & belt, and custom 94 tune. Planning to do lower pulley and possibly a meth tank in the trunk, single nozzle.

I do not have regular access to E so not an option

Katech_Mike · 03-17-2023, 08:29 AM

Consult your tuner.

Depending on what size lower you add you will begin to run into the limits of the fuel system.

KingLT1 · 03-17-2023, 08:31 AM

Most don't do both because of heat increase with stock blower. You would be better off porting the supercharger. Once you do cam, fuel system, cooling mods, race port, meth or E, then you do lower for more boost. Basically you need more octane and efficiency vs boost at this point with your build.

dfxrte · 03-17-2023, 08:52 AM

got it thanks. makes sense.

JSH · 03-17-2023, 08:53 AM

Quote:

Originally Posted by dfxrte

hi all,

wondering if there is any benefit or just preference to swap one over the other.

I have my upper pulley and belt swapped out and planning to do the lower, but it seems so many ppl either choose to do lower or upper and not always both (unless heavily modified).

Is it too risky to do both or something?

For context, I am very mildly modified with just headers, intake, upper pulley & belt, and custom 94 tune. Planning to do lower pulley and possibly a meth tank in the trunk, single nozzle.

I do not have regular access to E so not an option

FWIW - Hennessey did a 10% lower on my 1.7L 850 pkg. on pump gas, and they left the TB and SC untouched. They don't change the upper on any 1.7L pkg.

LiqTenExp · 03-17-2023, 09:49 AM

There is more belt contact area on the lower, therefore doing the lower does not increase the opportunity for belt slip like it would on the upper. I've done both but I'm not running the stock blower.

Recommendation on stock blower is to do the lower. The stock blower has limited headroom to grow and you'd be wasting money on upper pulley or porting if you continue to be serious with modifying the car, eventually you'll need a better blower. If you replace the stock blower you can still keep the upgraded lower pulley.

Z OH 6 · 03-17-2023, 10:53 AM

9.45" lower with a Kong ported blower is about as far as you can go on stock fueling and it's recommended to upgrade the heat exchangers and add an aux overflow tank for more cooling volume.

dfxrte · 03-17-2023, 10:54 AM

Quote:

Originally Posted by LiqTenExp

There is more belt contact area on the lower, therefore doing the lower does not increase the opportunity for belt slip like it would on the upper. I've done both but I'm not running the stock blower.

Recommendation on stock blower is to do the lower. The stock blower has limited headroom to grow and you'd be wasting money on upper pulley or porting if you continue to be serious with modifying the car, eventually you'll need a better blower. If you replace the stock blower you can still keep the upgraded lower pulley.

having done the upper, catless headers and rotofab i made 656 wheel and 692 torque on a custom 94 tune, I'd have to check the boost we were running again but it was very moderate.

manual btw, been very reliable since doing it about a year ago

SJFGTO · 03-20-2023, 09:48 AM

Quote:

Originally Posted by Z OH 6

Agreed, when one person decides to attack someone's character instead of providing any useful info, this is what happens. At least I provided useful info before he showed up.

Agreed. And to the OP, I would stick with the lower and port the stock blower for maximum bang for the buck at this point. Very happy with the lower that Vengeance recommended and installed. No heat issues and the combo with LTs and a tune is felt all the way to the redline and has been super reliable.

Z OH 6 · 03-20-2023, 09:58 AM

Quote:

Originally Posted by SJFGTO

Agreed. And to the OP, I would stick with the lower and port the stock blower for maximum bang for the buck at this point. Very happy with the lower that Vengeance recommended and installed. No heat issues and the combo with LTs and a tune is felt all the way to the redline and has been super reliable.

Same here with my Vengeance build.

03-17-2023, 08:00 AM	#1
dfxrte Drives: 22 ZL1 M6 Join Date: Oct 2018 Location: GTA Posts: 353	Upper pulley VS lower pulley VS doing both hi all, wondering if there is any benefit or just preference to swap one over the other. I have my upper pulley and belt swapped out and planning to do the lower, but it seems so many ppl either choose to do lower or upper and not always both (unless heavily modified). Is it too risky to do both or something? For context, I am very mildly modified with just headers, intake, upper pulley & belt, and custom 94 tune. Planning to do lower pulley and possibly a meth tank in the trunk, single nozzle. I do not have regular access to E so not an option __________________ Sold: '17 m6 2SS [arctic blue] Current: '22 m6 zl1 [vivid orange]

03-17-2023, 08:31 AM	#3
KingLT1 Drives: 2016 1SS NFG A8 Join Date: Aug 2017 Location: 46804 Posts: 6,838	Most don't do both because of heat increase with stock blower. You would be better off porting the supercharger. Once you do cam, fuel system, cooling mods, race port, meth or E, then you do lower for more boost. Basically you need more octane and efficiency vs boost at this point with your build. __________________ 2016 NFG 1SS A8 Options-2SS Leather/NPP Perf. mods-Whipple 2.9/Fuel System/Flex Fuel/103mm TB/Rotofab Big Gulp/Cat Deletes/Corsa NPP Per. times- 10.5 @ 137 w/ 1.8 60ft Full weight on 20's 1200DA

03-17-2023, 08:52 AM	#4
dfxrte Drives: 22 ZL1 M6 Join Date: Oct 2018 Location: GTA Posts: 353	got it thanks. makes sense. __________________ Sold: '17 m6 2SS [arctic blue] Current: '22 m6 zl1 [vivid orange]

03-17-2023, 09:49 AM	#6
LiqTenExp Drives: 2017 ZL1 Join Date: Jan 2017 Location: NJ Posts: 906	There is more belt contact area on the lower, therefore doing the lower does not increase the opportunity for belt slip like it would on the upper. I've done both but I'm not running the stock blower. Recommendation on stock blower is to do the lower. The stock blower has limited headroom to grow and you'd be wasting money on upper pulley or porting if you continue to be serious with modifying the car, eventually you'll need a better blower. If you replace the stock blower you can still keep the upgraded lower pulley. __________________ 2017 Camaro ZL1 Coupe M6 (847whp Dynojet on 93)

03-17-2023, 08:29 AM	#2
Katech_Mike Drives: 2015 Camaro ZL1 Join Date: Oct 2020 Location: Clinton Twp, Michigan Posts: 257	Consult your tuner. Depending on what size lower you add you will begin to run into the limits of the fuel system.

03-17-2023, 10:53 AM	#7
Z OH 6 Drives: 2021 Red Hot ZL1 Join Date: Sep 2020 Location: GA Posts: 3,190	9.45" lower with a Kong ported blower is about as far as you can go on stock fueling and it's recommended to upgrade the heat exchangers and add an aux overflow tank for more cooling volume.

User Name		Remember Me?
Password