CobraAaron

I'm fairly new to the Corvette world but have been around performance cars my whole life. I just bought an 09 Z06 with H/C/I setup. It currently has LG 1 3/4" on it and a catted mid pipe and stock catback.

I'm thinking about switching to Kooks 2" and off road midpipe w/ LG GT4 catback. Do you think the 2" primaries will be too much for my setup?

Details about current setup:
Vararam VR-SCR
CAI Nick Williams 102mm Throttle Body DBW
F.A.S.T. 102mm Intake w/ with custom port match to TB
PRC LS7x 265cc 7.0L CNC Heads
2.200”/1.61” Titanium Intake/ Stainless Exhaust valves
PRC .675” Lift EHT Spring Kit
Katech Torquer LS7 110 camshaft 220/244@.050. 615/.648 lift,110 LSA +004

BearZ06

Header discussion:

http://forums.corvetteforum.com/c6-t...4-headers.html

0Anthony @ LGMotorsports

Yes....to big unless you are shooting for a gain in the 6500-7500 RPM range and loosing every where else.

What does it make for power now? 530-540whp?

A 1 7/8 might pick up a little bit...just depends on how you want it to change the curve and pick up power.

Unreal

Yes. I made 1047 on 1 7/8" LG, and I am swapping to 2" because I'm going for 1100+. For 600-900 I would stick with 1 7/8".

If you really want to goto 1 7/8" you can buy my 1 7/8" once I pull them off.

PRE-Z06

That cam was designed to make torque as are your 1.75" headers, so imo they go well together. The Torquer 110 doesn't breathe as well up top with it's valve events, so I wouldn't put on a 2" header designed to make more high rpm power at the cost of low end. That's like putting in a large cam with a small header combo that is trading off the top end power of bigger cam and keeping it choked up with smaller exhaust. The combination of parts is best, even if just chasing a peak dyno number. 1.875" are a nice compromise, but not sure you would consider them worth your troubles.

CobraAaron

Thanks Anthony. That's the power that I'm making right now, 540rwhp. After reading everyone's responses, I'm leaning towards staying with my current exhaust setup until I switch cams. Also, I didn't realize LG was so close to me here in TX. I'll be giving you guys a call soon.

CobraAaron

This makes sense. Thanks for the clear explanation. For now, I think I'm just going to change the stock mufflers for the GT4 and remove the cats from the midpipe. Im going to leave the headers as is.

0Anthony @ LGMotorsports

Anytime, I'm almost always here.

PRE-Z06

You're always welcome