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Cat-Back time: what size Mandrel ? Map? 2.8 by Kuta
Started on: 05-17-2008 07:11 AM
Replies: 7
Last post by: Kuta on 05-21-2008 03:23 PM
Kuta
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Report this Post05-17-2008 07:11 AM Click Here to See the Profile for KutaClick Here to visit Kuta's HomePageSend a Private Message to KutaDirect Link to This Post
Part list:
Flowmaster 80 . en route FedEx
Resonator tips : [Flowtech (Terminator) or Hedman (Hot Tips)]
Mandrel bent pipe, from cat (delete) to back

The only question is the Mandrel bent pipe.
Car is an 86.5 GT, stock, without cat.

1) What size- 2" ?
My engine has 76k so hope it won't need to be upgraded anytime soon.

2) Anybody have a part list for the mandrel bends / straight pipe ? Map?
I can guess what pipes I need from pictures I saved.
The stock system is gone (replaced with a shade-tree half-assed system- only 1 outlet, which leaks terribly)


I ask #1 because it seems a bigger pipe is a louder sound- is that true? Does it sound different?
[some posts on here with 2.5" said talking was difficult inside the car- that's too loud]

I want it *loud* when I push it, but quiet if I drive modestly.

[This message has been edited by Kuta (edited 05-19-2008).]

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Kuta
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Report this Post05-17-2008 04:19 PM Click Here to See the Profile for KutaClick Here to visit Kuta's HomePageSend a Private Message to KutaDirect Link to This Post
goin to work
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Kuta
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Report this Post05-19-2008 02:22 PM Click Here to See the Profile for KutaClick Here to visit Kuta's HomePageSend a Private Message to KutaDirect Link to This Post
i got the flowmaster in- it's huge!
if you guys say it works though i'm sure it will

i'd like to buy the mandrel without guessing
the muffler to tips i can guess,
but the long pipe that goes under teh car is bent strange
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Intel
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Report this Post05-20-2008 07:26 AM Click Here to See the Profile for IntelClick Here to visit Intel's HomePageSend a Private Message to IntelDirect Link to This Post
My whole exhaust system is 2.5" and seamless high grade stainless tubing, I don't remember if I have a Flowmaster or Magnaflow stainless muffler but I do have the Magnaflow dual stainless tips.
My cat has been deleted. At first it was a bit noisy inside the car but then I wrapped everything from the Y pipe to the muffler with termotec heat wrap and put on a few thick layers of heat spray. The sound inside changed from loud to a more deep rumbling.
I've had this setup nearly 2 years without any problems.
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Arns85GT
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Report this Post05-20-2008 08:55 AM Click Here to See the Profile for Arns85GTClick Here to Email Arns85GTSend a Private Message to Arns85GTDirect Link to This Post
I did a 2.5" with a Magnaflow stainless in the CAT position. I can tell you it gets compliments all the time.

Here is a list based on my best recollection

For you, a 2" to 2.5" converter piece, a muffler, (the Magnaflow 5" round fits)
Then in Walker pipes
1 - J
3 - L
some 2.5" length, maybe a 6 footer to be safe, but 4' might do it

I fabricated a T at the rear cradle notch. If you can weld this is not hard.

It goes J at the front cradle opening, L welded in at an angle to aim for the rear cradle opening, a T that is slightly off center, ( I use a band clamp in front of the T because I have a rear sway bar and need to have the system come apart there), then a bend for each tip. As exhaust systems go, this is not a hard one, when compared to the stock muffler setup. It also saves weight.

Hope this helps.

Arn
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Kuta
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Report this Post05-21-2008 01:05 AM Click Here to See the Profile for KutaClick Here to visit Kuta's HomePageSend a Private Message to KutaDirect Link to This Post
O.K. thanks for the help.
I didn't realize to cut a J bend @ the angle needed,
and just weld it to another piece with that angle cut.

I have an 8.5 amp Firestorm angle grinder / cut off wheel, hopefull that will be accurate enough.

But the bends don't have to be perfect angles to fit, you say.

Both your cars are 2.8 ?
maybe i'll do the 2.5" with heat-wrap route. Deep sounds good.

if it's still too loud i can put a 5" round magnaflow (or other) :
into the CAT position.

Were either of you using Resonator tips ? i read that gets rid of some rasp (leaving the rumble)
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Arns85GT
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Report this Post05-21-2008 08:24 AM Click Here to See the Profile for Arns85GTClick Here to Email Arns85GTSend a Private Message to Arns85GTDirect Link to This Post
Actually the angles have to be pretty darn close if you are welding pipe. I place them, and mark them with a Sharpie. I generally don't weld on the car because I don't have a lift, but, if you can spot weld them in a trial hanging, then it will speed up the job. You need a chain type pipe cutter IMHO. The angle cutting discs do a job, but the pipe cutter is a much cleaner job and you can cut it while in place.

Measure twice.........

Arn

Edit - resonator tips are not a huge help. When you get on the throttle and the car is sending sound a couple of blocks behind you, and you don't want the cops to hear you with their windows rolled up, the tips will not help much at all. I would definitely plan on a muffler in the CAT position, both from the cost and sound points of view.

[This message has been edited by Arns85GT (edited 05-21-2008).]

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Kuta
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Report this Post05-21-2008 03:23 PM Click Here to See the Profile for KutaClick Here to visit Kuta's HomePageSend a Private Message to KutaDirect Link to This Post
the chain-type pipe cutter looks cheap & effective, but no angles on straight-pipe (should i run into an obstacle)
if i need to i'll consider this- "heavy-duty" means it might not fall apart after 3 cuts cut-off saw
the cheapie one doesn't include a cutting wheel for $20 less.

thanks for the tip on tips ;-) i'll order another muffler so i have it on hand when i get sick of the noise
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