Well I just recently bought a obx header, and a megan muffler. When I went to the shop to have it installed the guy told me that i need to go with a mandrel bent catback system for the best performance. I have looked all over the place for a system that i like, but i can't find one with a muffler I like (i.e. magnaflow/ rksport). Should I buy the system and cut/weld on a different muffler, or should I go with a regular bent system from the cat back. From what I have heard, it doesn't matter if it is mandrel or not from the catalytic converter unless you are boosting. I am also looking at getting a high flow cat. Please shine some wisdom on this issue.

he's a moron. you might get a 1hp gain from mandrel bends vs compression bends. the only difference is that mandrel bends keep a perfect circle in the bend and compression bends oval out. there is no size restriction or lost diameter through the bends like there are with crush bends. mandrel bends are just prettier and far more expensive.

just have a compression bent catback made, it'll be cheaper






I was a retard, and now I'm permanently banned.

/\ /\ /\ Hes right not haveing mandrel bent isn't gonna kill you and compression bent is just fine.Sounds like this guy just doesn't want to do your car thats all.




Semper Fi SAINT. May you rest in peace.

Dude, even if the guy says you need mendrel bent pipes, that doesnt mean you need to go buy a cat-back for your car. He should be able to mandrel bend the pipes for you! A lot of people that want mandrel bent pipes do this. They buy the muffler, cat, and resonator if they want one. Then they go to a shop and the shop can put it all together, whether they compression bend it or mandrel bend it, shops can do both, just costs different. If that guy cant mandrel bend pipes at his shop for you, you definitely need to find somewhere else to go to get your exhaust done, cause if he cant mandrel bent, then how good do you think he is going to be at compression bending??

^^^^^^WRONG. Mandrel bending machines are expensive and most exhaust shops do not have them thats the reason why he can't do it not because he's incompatint (lazy maybe). Like the rest said compression bends aren't gonna make enough of a difference, just make sure you stay away from crush bent.




2006 Cobalt SS 2.4L 9.6 @74mph 1/8th mile w/2.28 60ft

Mandrel benders are very expensive and I'm betting this shop doesn't have one but hes useing it as an accuse to get you to go away cause he doesn't want to install parts that
hes not selling you.




Semper Fi SAINT. May you rest in peace.

I've noticed at a lot of shops, that they will charge you more to bend the exhaust pipe and bolt up the muffler you brought in than it will cost to buy the kit that they order for your car. When you have them bend the pipe custom, they charge you the labor, materials, AND the install fee if you have them bolt it up. I went into a place in Des Moines and they wanted like $150.00 to bend the pipe for me on a mendrel. I'd rather stick my hand in a blender and hit "liquify". Hell, you can buy a crappy cat back system from Jegs for that much, ditch the crappy "muffler" they sell with it, and put on your own muffler. That pipe is mendrel bent ,2.25", aluminized steel. Not the best option, but better than what the shop charges.

not necessarily. i had a stainless steel 2.25" exhaust made for my car for $150 and that is including the installation of my magnaflow high flow cat




I was a retard, and now I'm permanently banned.

ive heard that most hi flow cats make almost no difference from the stock one is this true?

Andrew Wallace wrote:ive heard that most hi flow cats make almost no difference from the stock one is this true?

Heh.... most aftermarket high-flow cats trip the Check Engine light because they flow TOO much air... haven't seen a stock one do that

The stock cat is pretty good... but if you want to match pipe sizes (when doing a new header/downpipe), it chokes off the flow going from 2.25" or 2.5" to 2, and back again.

Lenko, John Lenko wrote:

Andrew Wallace wrote:ive heard that most hi flow cats make almost no difference from the stock one is this true?

Heh.... most aftermarket high-flow cats trip the Check Engine light because they flow TOO much air... haven't seen a stock one do that

The stock cat is pretty good... but if you want to match pipe sizes (when doing a new header/downpipe), it chokes off the flow going from 2.25" or 2.5" to 2, and back again.

yup. take a glance at my registry for example. it's 2.25" ALL the way back




I was a retard, and now I'm permanently banned.

what a good resonator like how long should i get i getting a magnaflow cat and have a rsm header?

lawrence joven wrote:Well I just recently bought a obx header, and a megan muffler. When I went to the shop to have it installed the guy told me that i need to go with a mandrel bent catback system for the best performance. I have looked all over the place for a system that i like, but i can't find one with a muffler I like (i.e. magnaflow/ rksport). Should I buy the system and cut/weld on a different muffler, or should I go with a regular bent system from the cat back. From what I have heard, it doesn't matter if it is mandrel or not from the catalytic converter unless you are boosting. I am also looking at getting a high flow cat. Please shine some wisdom on this issue.

Do not listen to that guy. Yes mandrel bent is better, but for the money on a everyday project car no it is not. If you were building a straight up race car, I would say spend the money. Look at my car I'm running crushed bent exhaust and pull 14.8's all motor.

Quote:

The stock cat is pretty good... but if you want to match pipe sizes (when doing a new header/downpipe), it chokes off the flow going from 2.25" or 2.5" to 2, and back again.

This is true, but you can always still use the stock cat and have the shop cut the opening and outlet to match the exhaust size you are using. I had my stock cat cut first to a 2.25", and later to a 2.50" exhaust. Not all exhaust shopw will do that, but some will.



FU Tuning

remember, the place your gonig to to get work done wants to talk you into other things to get more cash outta you

Yeah everyone has said what i was going to say. I would just find another shop and get a crush bent pipe. My opinion i would go 2.5 for crush bent pipe and 2.25 for mandrel bent.


2004 Grand Prix GTP (Competition Group)
SOLD-->1999 Z24 5M-#30 to register on JBO
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