Exhaust outlet hole size?

[RM1SepEx]

Looking for ideas on how large and how to finish the hole for my 3 inch exhaust, it will come out in the lowest section of the rear clip behind the right rear tire.

45218

I'm thinking that I need a 4 inch hole for clearance to allow for movement and to avoid melting the fiberglass.

Ideas?

[Hindsight]

Do you have a flex joint in your pipe so you can mount the pipe to the frame with a rubber isolator? That will reduce movement. Most people who make an exit hole will add a metal trim ring bezel. The ID of the bezel hole is smaller than the fiberglass hole so if there is any contact, it will be exhaust pipe to trim bezel.

[RM1SepEx]

no flex, no room for one either!

[Hindsight]

Frozenboost sells a 4" long joint. I bought one. I can't get it to flex in my hand though :-\

I can't remember which engine mounts you are running but there shouldn't be too much exhaust movement if you are running the harder mounts, like the Cusco style. If it were me, I'd only leave 1/4" clearance between the tip and metal bezel (so 1/2" total hole diameter difference) and I would probably leave another 1/4" gab between bezel ID and fiberglass. That should keep you plenty safe.

[Kurk818]

I left about 3/4" around my exhaust. Its a rigid one piece with a rubber hanger like OEM. I still end up seeing fiberglass rub on the tip after a drive.

http://i.imgur.com/lyXcrkPl.jpg

http://i.imgur.com/PFZx9ZCl.jpg

[RM1SepEx]

I have Cusco mounts, not sure how much it will move. I used the FFR exhaust mount with the rubber sleeve off a bracket bolted to the transaxle. I'm thinking of starting with a 4 inch hole for my 3 inch pipe leaving 1/2 clearance

[Bob_n_Cincy]

I have Cusco mounts, not sure how much it will move. I used the FFR exhaust mount with the rubber sleeve off a bracket bolted to the transaxle. I'm thinking of starting with a 4 inch hole for my 3 inch pipe leaving 1/2 clearance

Dan,
I used a 4" ID ring on my 2" exhaust. I think it looks good.
Bob

http://thefactoryfiveforum.com/attachment.php?attachmentid=45274&d=1441847201

[RM1SepEx]

you only have a 2 inch exhaust???

[Bob_n_Cincy]

you only have a 2 inch exhaust???
I'm using the FFR pipe. I thought it was 2", I may be wrong.
Bob

45275

I rotated it so the O2 sensor points down.

[john g]

The FFR exhaust is 2 1/2 inches. I cut a 3 1/2 inch hole so that I would have 1/2 inch margin all around to account for vibration and measurement error. I also cut a trim ring from scrap aluminum using two hole saw rings mounted concentrically on the arbor.

[Bob_n_Cincy]

I was incorrect thinking my exhaust was 2". John is correct at 2-1/2".
I used an 4" billet aluminum (ebay) to go around my exhaust. I had to shape it to the contour of the body. I think it came out great.

EDIT: SHOULD I POWDERCOAT IT TO MATCH THE OTHER BLUE TRIM?
Bob

http://thefactoryfiveforum.com/attachment.php?attachmentid=45315&d=1441939968

[RM1SepEx]

Yes

[RM1SepEx]

So with a white body how far should the exhaust pipe extend out to avoid the dreaded blackened bodywork? I started with a 4 inch hole for the 3 inch pipe and it extends out to be about as wide as the body...

How much shorter should I cut it before I weld it up?

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[RM1SepEx]

got some quick inputs, including from a dyno owner who has melted fascia panels...

As long as possible for that location but angled to match the body panel contour

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I'll bring my IR gun to monitor temps when I dyno her next week!