Pontiac G8 Forum banner

1 - 12 of 12 Posts

·
Registered
Joined
·
8 Posts
Discussion Starter #1
So I have taken about 45 mins of looking around and none of the information seems to be very current on the subject. SO, here I am!

I am looking at starting the mods on my 09 GT. Currently she only has a Magnaflow Street Series Catback on it. I'm squirreling away money for the DOD delete on it and the exhaust is on my agenda. I was interested in LT headers but all the info I see with my exhaust has said that it will need connectors fabricated to bolt to my catback. Since all the posts I've stumbled across are before the High Flow Cats were released I wanted to get opinions on which current production headers are doing well and could possibly match up to my exhaust without fabrication (if they exist). Or what sort of header options with HF cats would be preferable nowadays! I figure I'll do the header install, put a OTR intake and get it tuned until its cam time. Thanks for the input everyone!
 

·
Registered
Joined
·
3,429 Posts
Only aftermarket headers that will mate up to stock exhaust, or aftermarket catback without any modification are SLP "Longtube" headers.

Otherwise, with the better headers on the market (ARH, Kooks), you'll need to cut the catback to make room for the longer length of the primaries for the headers and collector that is further back in the car.
 

·
Registered
Joined
·
8 Posts
Discussion Starter #3
Only aftermarket headers that will mate up to stock exhaust, or aftermarket catback without any modification are SLP "Longtube" headers.

Otherwise, with the better headers on the market (ARH, Kooks), you'll need to cut the catback to make room for the longer length of the primaries for the headers and collector that is further back in the car.
Ah okay, see all the old posts that I’ve come across that mentioned any details other than the headers won’t fit without modification didn’t mention the catback had to be cut. Any idea how much pipe needs to come off? Also are the kooks 1 7/8 pretty much still the main recommendation by everyone?
 

·
SUSP3CT
Joined
·
1,027 Posts
Kooks, ARH and Stainless Works are all reputable brands and the best choices for the G8. The Kooks will mate directly to a Solo aftermarket exhaust with their "Solo-Kooks" connection. That's the setup I currently have.

If you want to keep you Magnaflow you'll have to do some custom fabrication which any reputable shop should be able to do.
 

·
Registered
Joined
·
520 Posts
Could also go Kooks mids + HFCs. I know that mounts to the stock catback as I have that. Might give up a few HP over LTs, but may be worth it just to avoid the headache.
 

·
Registered
Joined
·
102 Posts
Couldn't one go Kooks LTs/x-pipe? I have that setup on my car connected to the stock GT mufflers. Works fine, even with my mostly skill(less) fitment skills.
 

·
Registered
Joined
·
28 Posts
I think The_Dustonian has the Magnaflow 16857 catback exhaust that bolts up to the stock cats. If he had the Magnaflow 16883, he could go the Kooks X-Pipe route.

This is my opinion, so take it for what it's worth:
I would go with Kooks L/T and buy a set of quality HFC. As long as you go to an exhaust shop that knows what they are doing; it would just be another day in the office for them. You can order Kooks high flow cats for about $300 for the pair. The Corsa connection with high flow cats are almost $600. If the exhaust shop charges $300-400 for the work; your overall cost would not be that different than what you would have paid if there was a system that bolted up to your catback.

The good thing is that you have a 3" catback exhaust; my corsa is a 2.5" system. I would have loved to have a 3" exhaust from the headers all the way back; so this is actually a great opportunity for you. A unique exhaust that no other G8 has and would be one of the best flowing exhaust systems.

However, Kooks Mid-lengths are definitely an option worth considering if you don't want to modify your magnaflow catback.
 

·
Registered
Joined
·
8 Posts
Discussion Starter #8
I think The_Dustonian has the Magnaflow 16857 catback exhaust that bolts up to the stock cats. If he had the Magnaflow 16883, he could go the Kooks X-Pipe route.

This is my opinion, so take it for what it's worth:
I would go with Kooks L/T and buy a set of quality HFC. As long as you go to an exhaust shop that knows what they are doing; it would just be another day in the office for them. You can order Kooks high flow cats for about $300 for the pair. The Corsa connection with high flow cats are almost $600. If the exhaust shop charges $300-400 for the work; your overall cost would not be that different than what you would have paid if there was a system that bolted up to your catback.

The good thing is that you have a 3" catback exhaust; my corsa is a 2.5" system. I would have loved to have a 3" exhaust from the headers all the way back; so this is actually a great opportunity for you. A unique exhaust that no other G8 has and would be one of the best flowing exhaust systems.

However, Kooks Mid-lengths are definitely an option worth considering if you don't want to modify your magnaflow catback.
The plan was to get rid of the cats. So the LT headers I’d be looking to bolt to the catback. I’m pretty close to having a shop that will do whatever modifications I need on the exhaust. My normal go to place has raised their prices over double since I last saw them. Unfortunately the work isn’t twice as good to match it.
 

·
Registered
Joined
·
28 Posts
Yeah, I think that would be even easier for the exhaust shop to fabricate. The 3" might be a little big for now, but I think it'll be good with an intake, LTs, cam and tune.

Ouch, yeah, good work isn't cheap, but cheap work isnt worth the price. Hopefully you'll find a solid shop!
 

·
Registered
Joined
·
8 Posts
Discussion Starter #10
Yeah, I think that would be even easier for the exhaust shop to fabricate. The 3" might be a little big for now, but I think it'll be good with an intake, LTs, cam and tune.

Ouch, yeah, good work isn't cheap, but cheap work isnt worth the price. Hopefully you'll find a solid shop!
Thanks, hopefully the guys I'm talking with pull through and deliver some good work. I think my exhaust is 2.5" but it was on the car when I got it last year. I'm not entirely sure how to tell without pulling the exhaust loose and measuring. So time will tell in that regard. For now the car will be headers, intake, the exhaust, and a tune. The cam will be later next year. Then if all goes well I may throw a supercharger on.
 

·
Registered
Joined
·
211 Posts
Thanks, hopefully the guys I'm talking with pull through and deliver some good work. I think my exhaust is 2.5" but it was on the car when I got it last year. I'm not entirely sure how to tell without pulling the exhaust loose and measuring. So time will tell in that regard. For now the car will be headers, intake, the exhaust, and a tune. The cam will be later next year. Then if all goes well I may throw a supercharger on.
I'm in a similar spot as The_Dustonian. I have the magnaflow street series 16795 2.5" catback. I'd like to do long tubes but still trying to figure out what size, 1 3/4 or 1 7/8, and cats or no cats? People who don't run cats, do your cars stink like exhaust inside the car?
 
1 - 12 of 12 Posts
Top