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Considering 2.5" high flow exhaust

Posted: April 19th, 2016, 9:30 am
by Kahlis
I already bought an eBay header for $90 and figured it a reasonable amount to waste if they are garbage. Although visually they are very well put together (welds are solid and the head flange is just as thick as OEM). Anyone else use these?
VZM.IMG_20160304_225526.jpg
The next step will be to construct a 2.5" exhaust with a high flow cat (Thunderbolt, Magnaflow, Flowmaster, etc) and a 40~50 series Flowmaster muffler. I'd prefer to avoid a "cat-back" system like Gibson, only because their bolt on kits are around $900 or so. Are there companies that offer 2.5" pipe that meet ZJ specs (bends, angles, etc) for reasonable $$ or would it be best to have a local shop craft it? My welding skills are 'decent' and I don't mind doing it myself.

Re: Considering 2.5" high flow exhaust

Posted: April 19th, 2016, 9:39 am
by purple_jeep
Nick aka Kolak on JeepForum has a mandrel bent 2.5" Exhaust system for the ZJ and can do a good deal on the cat as well. I ordered it from him in 2009 and it turned out great, currently in the process of getting a down pipe made up to match it and the thorley header I am running.

His email is [email protected]

Cheers

Chris

Re: Considering 2.5" high flow exhaust

Posted: April 19th, 2016, 10:01 am
by Kahlis
purple_jeep wrote:Nick aka Kolak on JeepForum has a mandrel bent 2.5" Exhaust system for the ZJ and can do a good deal on the cat as well. I ordered it from him in 2009 and it turned out great, currently in the process of getting a down pipe made up to match it and the thorley header I am running.

His email is [email protected]

Cheers

Chris

Email sent! Many thanks.

Re: Considering 2.5" high flow exhaust

Posted: April 19th, 2016, 10:26 am
by jeepman
I ordered a Mandrel bent Hot rod kit from Magnaflow and a Magnaflow high flow cat and XL muffler and built my own Exhaust system...

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Re: Considering 2.5" high flow exhaust

Posted: April 19th, 2016, 10:32 am
by Kahlis
Very nice work!!!!

Re: Considering 2.5" high flow exhaust

Posted: April 19th, 2016, 11:08 am
by SilverXJ
I have kolak's 3"(because that powerful v8) mandrel bent setup on the 5.2L in my ZJ. Fits well and it has been through 3 winters already and is holding up well.

Re: Considering 2.5" high flow exhaust

Posted: April 19th, 2016, 12:58 pm
by Kahlis
Kolak got back to me, but I'm confused.

Based on the description of his kit, he provides a Magnaflow high flow converter, Flowmaster muffler and a mandrel bent exhaust pipe. He further recommends the exhaust shop "uses 2.5" tubing to replace the tubing that goes from the exhaust manifold to the converter, and of course to tie the muffler, converter, and tailpipe together".

So the only part of this kit that is "unique" is his mandrel bent exhaust pipe?


EDIT: Kolak replied. I'm good on this question!

Re: Considering 2.5" high flow exhaust

Posted: April 19th, 2016, 12:59 pm
by Kahlis
Has anyone used/heard of Thunderbolt?

http://performance-curve.com/425250.aspx

Re: Considering 2.5" high flow exhaust

Posted: April 25th, 2016, 10:39 pm
by Shadowdrop
My concern is that the header collector is 2.125", so a 2.5" exhaust after is going to get pinched at the header. I'm thinking the best option to avoid a bottleneck is to use the later dual-outlet header and constructed a y-pipe?

Re: Considering 2.5" high flow exhaust

Posted: April 27th, 2016, 8:24 am
by Kahlis
Shadowdrop wrote:My concern is that the header collector is 2.125", so a 2.5" exhaust after is going to get pinched at the header. I'm thinking the best option to avoid a bottleneck is to use the later dual-outlet header and constructed a y-pipe?
The muffler shop is going to chop the collector and make it 2.5".

Re: Considering 2.5" high flow exhaust

Posted: April 27th, 2016, 8:45 am
by jeepxj3
Kahlis wrote:
Shadowdrop wrote:My concern is that the header collector is 2.125", so a 2.5" exhaust after is going to get pinched at the header. I'm thinking the best option to avoid a bottleneck is to use the later dual-outlet header and constructed a y-pipe?
The muffler shop is going to chop the collector and make it 2.5".
Please post a pic of that.

Re: Considering 2.5" high flow exhaust

Posted: April 27th, 2016, 8:53 am
by Kahlis
Yup, sure will.

Not sure if this has been attempted before, but I'm willing to give it a shot. Like I said in my first post, the header is an "eBay special" that only ran me $90. If it goes to shit I'll find another avenue.

Re: Considering 2.5" high flow exhaust

Posted: April 27th, 2016, 10:18 am
by gradon
I chopped the 2.5" flange off a NOS Clifford ceramic coated header and have a 3" v-band to be welded onto it. I'm tempted to find a 3" ss-kit like above and put my brother to work, but think I'll just shell out the $ to MBS in Pasadena. I might buy a 3" Thunderbolt metallic spun cat as well.

Re: Considering 2.5" high flow exhaust

Posted: April 27th, 2016, 12:41 pm
by Kahlis
gradon wrote:I chopped the 2.5" flange off a NOS Clifford ceramic coated header and have a 3" v-band to be welded onto it. I'm tempted to find a 3" ss-kit like above and put my brother to work, but think I'll just shell out the $ to MBS in Pasadena. I might buy a 3" Thunderbolt metallic spun cat as well.
The plan doesn't sound outrageous - I'm sure a good muffler shop does this often for people like us wanting more outta their exhaust systems. Thunderbolt (or as I later researched is the model - the company is AP Exhaust Technologies) are good; just not mainstream like MagnaFlow or Flowmaster. Shit, the price alone is worth giving it shot.


I almost forgot we already talked about being from the DC/MD area. My wife and I just bought a house in Elkridge - once I finish with my military tour here on the west coast I'll be getting back home. We gotta meet up!