another REAR EXIT exhaust inquiry

[Real Time]

Hi all,

I'm a ways off before starting my build but this is one I think I need to iron out beforehand. I've done dozens of searches but still don't see my way to a clear finish. (maybe that's part of the fun...lol).

To be clear, I am looking to go between tube rails and exit out the back.

I see some put sleeves in the crossmember and others notch it. I'm leaning towards the sleeves.
I'm planning on a Coyote from Mike Forte.
As far as what headers to use I'm sure I can work that out with Mike.
Mike has some really cool ideas about the follow up after the cross member too, but i'd love to hear thoughts form others.

More than anything I'd like to be able to speak with anyone that's done it.

-Coyote, IRS, are the tentative thoughts.
-I would be willing to forgo IRS if it meant a better system.
-I would like Cats to forgo any emission issues and quality muffs that keep sound down.

I'm sure I'll have a lot more questions for you guys as time goes on but think this will be my biggest challenge. If I get through this one I think I'll do great! lol!:D

George

[John4337]

I did UTC exhaust with a SBF and the 'old' IRS. Shorty headers flipped to dump toward the front, then under the footboxes. Exit is behind the rear wheels. Mufflers are SpinTech 7000 series, 2 1/4 thick, matches the 2 1/4 inch pipe. The pipes run under the LCA's. I built the system with the suspension at full droop to avoid clearance issues. 20,000 miles, no issues. PM an email address and I'll send some more photos or my cell if you'd like to talk.

https://thefactoryfiveforum.com/attachment.php?attachmentid=141365&d=1611531680

https://thefactoryfiveforum.com/attachment.php?attachmentid=141495&d=1611709702

[Real Time]

I did UTC exhaust with a SBF and the 'old' IRS. Shorty headers flipped to dump toward the front, then under the footboxes. Exit is behind the rear wheels. Mufflers are SpinTech 7000 series, 2 1/4 thick, matches the 2 1/4 inch pipe. The pipes run under the LCA's. I built the system with the suspension at full droop to avoid clearance issues. 20,000 miles, no issues. PM an email address and I'll send some more photos or my cell if you'd like to talk.

https://thefactoryfiveforum.com/attachment.php?attachmentid=141365&d=1611531680

https://thefactoryfiveforum.com/attachment.php?attachmentid=141495&d=1611709702

Hi John,

I'm looking to go between the rails if at all possible but will certainly keep this route in mind.

I love your car BTW and really appreciate your reaching out!!
Great touch with the black paint!

Thank you

George

[MB750]

I did UTC exhaust with a SBF and the 'old' IRS. Shorty headers flipped to dump toward the front, then under the footboxes. Exit is behind the rear wheels. Mufflers are SpinTech 7000 series, 2 1/4 thick, matches the 2 1/4 inch pipe. The pipes run under the LCA's. I built the system with the suspension at full droop to avoid clearance issues. 20,000 miles, no issues. PM an email address and I'll send some more photos or my cell if you'd like to talk.

https://thefactoryfiveforum.com/attachment.php?attachmentid=141365&d=1611531680

https://thefactoryfiveforum.com/attachment.php?attachmentid=141495&d=1611709702

Hey John, could we please get a pic of the undercarriage to get an idea how you ran the tubing? I'm planning on doing the same exact thing to my Mk4 but I also don't want to notch, channel, or modify the frame in any way.

[John4337]

Here are some more photos. Some were taken during the mock up stage so you'll see painters tape, etc and the side pipe cut outs were still there.

This is the side view at the header connection.

https://thefactoryfiveforum.com/attachment.php?attachmentid=141360&d=1611530470

Spin Tech muffler

https://thefactoryfiveforum.com/attachment.php?attachmentid=141361&d=1611530554

From muffler forward. I later added some DEI Exhaust wrap on this pipe as it is close to the footbox floor and transferred some heat. The muffler has a good air gap above and has not been an issue

https://thefactoryfiveforum.com/attachment.php?attachmentid=141362&d=1611530601

This is the drivers side out for paint. You can see the swing in to clear the rear LCA. The section of flex was an attempt to go out under the rear nudge bars, but I couldnt come up with a good solid mount, so I abandoned that and went to the exit behind the wheel

https://thefactoryfiveforum.com/attachment.php?attachmentid=141363&d=1611530666

This is the bend at the rear LCA

https://thefactoryfiveforum.com/attachment.php?attachmentid=166380&d=1651942688

Sort of an overview from the back. All the hangers were off the shelf bits from the parts store, or shop made

https://thefactoryfiveforum.com/attachment.php?attachmentid=166379&d=1651942688

Overall it doesn't hang much below the frame, speed bumps require caution. I have about 4 inches ground clearance at the mufflers.

Hope all this makes sense.

J