C6 NPP header choice?

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May 6, 2019 | 02:41 PM

#21

Tahoe

Instructor

Joined: Oct 2013

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I have same AR headers/ x-pipe/NPP/chipped/ 430 rwhp on my 6M 2011 GS. I have an intake shroud for outside air..Looking for info on benefits from underdrive pulley.

May 6, 2019 | 02:46 PM

#22

Tahoe

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Joined: Oct 2013

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which pulley & where did you find it? thanks

May 6, 2019 | 02:47 PM

#23

Spaceme1117

Safety Car

Joined: May 2016

Posts: 4,626

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From: Erlanger, Kentucky

Quote:

Originally Posted by Tahoe

Hi....reaching out for opinions/info.......I have an NA 2011 G.S./ 6M/AR headers & x-pipe/NPP mufflers/intake shroud/MGW short shift/
Would an underdrive pulley be worthwhile ? Whose pulleys are good? Where can I find used/ take offs? thank you

I assume you mean an underdrive harmonic balancer. For the amount of work involved, the gain is not worth it. 5 or 10 hp at best and you would never be able to feel that.

If you want more power that you can feel, the next step would be a cam swap.

May 6, 2019 | 02:50 PM

#24

Tahoe

Instructor

Joined: Oct 2013

Posts: 208

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Quote:

Originally Posted by Spaceme1117

thank you.....I'd like the 10 hp....who makes it?

Last edited by Tahoe; May 6, 2019 at 02:51 PM.

May 6, 2019 | 03:52 PM

#25

Spaceme1117

Safety Car

Joined: May 2016

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From: Erlanger, Kentucky

Quote:

Originally Posted by Tahoe

thank you.....I'd like the 10 hp....who makes it?

A couple of excellent brands are ATI and Powerbond. They have 10% and some 25% underdrive pulleys. You will need to look up the specific part numbers for your application. I would only go 10% mainly so you don't drop the output of your alternator too much. Corvettes are know to have sometimes sensitive electrical systems. You will also need to get the proper, shorter serpentine belt.

May 6, 2019 | 04:26 PM

#26

Tahoe

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Joined: Oct 2013

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I'd have to do other mods to make this worthwhile. thank you

May 6, 2019 | 04:46 PM

#27

Spaceme1117

Safety Car

Joined: May 2016

Posts: 4,626

Likes: 1,815

From: Erlanger, Kentucky

Quote:

Originally Posted by Tahoe

I'd have to do other mods to make this worthwhile. thank you

If you do the balancer, it’s a perfect time to do a cam upgrade. You have all the supporting mods to maximize gains from a cam. All you need are some springs, a few gaskets, and a modest cam.

May 7, 2019 | 02:25 AM

#28

jonjoy

Burning Brakes

Joined: Sep 2018

Posts: 1,023

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From: Auburn Al

Quote:

Originally Posted by MYCoupe

There are 4 O2 sensors. You will need a tune to delete the rear O2 sensors after the LT header install or you will get the dreaded CEL eventually.

if you put headers on you have to tune anyway, more air in more air out = tune. I don't think you can delete the rear O2 sensors on an LS3 like you can on a LS2