I have a 2008 M6 with the NPP exhaust option. I plan on purchasing the coated Kooks and catted X-pipe, will they bolt up to the stock NPP cat back? Or do I also need to upgrade the cat back exhaust?

Thanks -

 

I just installed the Kooks 1 7/8's with the 3" x 3" Xpipe and it bolted up perfectly to the factory tailpipes, which are the same as yours Im sure. Easy install. I would say get the 3" x 3" though since the last 24" is 3" instead of the 2.5" EVEN THOUGH both neck down to 2.5" right at the tailpipes. You'll gain atleast 1-2 rwhp..LOL

 

Get the 3 by 2 1/2 x-pipe works better than the 3 by 3 with a reducer
Which is your other choice!

 

the 3"x3" AND 3"x2.5" BOTH neck down to 2.5". both will fit the stock NPP exhaust. the ONLY midpipe that is 3" all the way is the ZO6 midpipe.



-Carl

 

Quick response, thanks! I feel at ease again.

 

Have the 1-7/8 with 3" Xpipe and hi flo cats great system bolts right up . BUT NOTE DO NOT USE KOOKS GASKETS ON HEADERS USE ORIGINAL GM AND YOU WONT HAVE ANY PROBLEMS.

 

whats wrong with the kooks gaskets? i used them. dont notice anything out of the ordinary

-carl

 

I am gonna do some hijacking here. Doesn't the new 08's come with an X-pipe. Can it be used or do I have to have a new x-pipe to make everything line up properly?

 

So, it probably wouldn’t be a bad idea to get with Mr. Gene Culley and order some new gaskets and head bolts?

 

ok.. cancell my last post of why use the supplied gaskets instead of the GM ones.

i didn't believe all the hipe. and just when i was gonna open my big mouth and brag about my kooks gaskets working fine. i went out and took on last look. leaking like a sob!! so about 1 hour of my life wasted swapping them out. and here is proof. 1000miles later

reason 1,920,922 to reuse stock GM gaskets!!





-carl

p.s. and yes, they were all torqued to spec using my craftsman tq wrench!!

 

What? 3 by 3 is well 3 by 3 Too big for 2 1/2 pipe
Without a reducer!

3 by 2 1/2 perfect fit. Where in the world did you get that

 

I got it straight from the horses mouth. KOOKS. i originally wanted a 3x3" pipe to match up to my z06 exhaust, which is 3", they said it reduces down the last 12" to 2.5".

please stop spreading the wrong info,,

i know the numbers dont look right, but thats how it is.. any c6 midpipe will work, only the z06 midpipe wont fit. the 3x3" is NOT the z06 midpipe.

-carl

 

Z0-6 takes the 3 by 3 X- pipe to work with the 3 inch catback. 3 by 2 1/2 X pipe fits the 2 1/2 pipe on a c-6. There is NO part of the 3 by 3 that is 2 1/2Got it straight?

 

ohmigod, you are so wrong. z06 take the Z06 midpipe, totally different part.
Z06 Midpipe: Part #: K6611S
http://marylandspeed.com/kooks-3-x-3...11s-p-874.html

c6 midpipe 3x2.5: Part #: K6608S
http://marylandspeed.com/kooks-3-x-2...08s-p-748.html

c6 midpipe 3x3: Part #: K6609S
http://marylandspeed.com/kooks-3-x-3...09s-p-749.html

Note the different part #'s

either way, 3"x2.5" or 3"x3" will work on his ls3 and NPP, as long as he doesn't get the z06 midpipe.

just give kooks a call, they will tell you the EXACT same thing. im done with this. ill accept apoplogy's in the form of PM's.

-carl

 

* X pipe 3 by 3 fits 3 inch catback so if his pipe is 3 inch,thats what he needs. 2 1/2 tail pipe like on mine needs the 3 by 2 1/2.

 

One has 2 1/2 outlet for 2 1/2 catback.
PERIOD. One has 3 outlet for 3 inch catback. Zo=6 for Z-06 cars!

 

Acording to the links you posted you are going to owe the apology. Links 1 and 3 both have 3" inlet and outlet. One is for the Z06 and one is for a C6 with a 3" aftermarket catback. 2.5" is not mentioned any where in the description. If a person had a 3" catback why would they want any part of the system 2.5"?

Link 2 has a 2.5" outlet and fits all C6 with a factory exhaust or 2.5" aftermarket catback.

I'm confused. If the 2 links state they have a 3' inlet and outlet why would you think one has a 2.5" outlet?

 

Thanks

 

OK OK One last post..
i found my EMAIL FROM Maryland Speed that talked straight to KOOKS.

----EMAIL-----
Dear carl
I talked to Kooks, and to connect to the Z06 Exhaust, you will need the 3" Z06 X-pipe (PT#6611S). I can switch this out at no additional cost.

The reason is-
C6 X-pipe 3" x 2.5" (PT#6608S) necks down in the middle to 2.5"

C6 X-pipe 3" x 3" (PT#6609S) that you ordered necks down at the very end right before the axleback to 2.5"

Z06 X-pipe 3" x 3" (PT# 6611S) is 3" all the way through and will fit a regular C6 w/ a Z06 exhaust.

I know it is confusing, but it will work. Also, I would recommend skipping coating the X-pipe. There is no advantage to it, and it actually makes the slip fits really hard to get togethor. Let me know what you want to do.

I know it sounds confusing, but trust me on this.
---EMAIL----


READ IT A WEAP!!

But just keep saying stuff that your not 100% positive about. everyone is an expert according to themselves.

so please prove me wrong and just call kooks and get your pe-pe slapped. good day

-carl

p.s. i too was as stubborn as you are now and it shows as i tried to order the 3x3 to bolt up to my z06 bi-mode exhaust, but that was months ago, and i have learned and since have tried to pass on the CORRECT info. it would be nice if they updated their website so this stuff stops happening.

 

read your OWN links for christ sakes. You still don't know what your talking about. The link says 3 by 3 inlet and outlet. Z0-6 3 inlet and outlet. 3 by 2 1/2. 3inch inlet 2 1/2 outlet Whats sooooo hard to understand. I know these things because I installed my own stuff.
You apparently don't or you would have a clue!