How close to the floor is your catalytic converter?

Anak · Jul 1, 2015

I do not have a proper baseline on account of the interesting workmanship of previous owners. I am working on replacing the entire exhaust system. I have a Borla 17039 header and a Magnaflow 445036 catalytic converter. Both are CARB EO approved for my '96. However, installed, I have about 1/8" between the heat shield on the cat and the body bracing under the floor. And that is after prying for all I am worth to try to get some clearance.

How does this compare to stock?

On the one hand I want as much ground clearance as possible, but on the other hand I know a catalytic converter puts out some real heat. I don't want to get undesirable side effects for all my efforts.

Johnnie Walker · Jul 1, 2015

Seems a bit close, regardless of what you do i hear an Airbake cookie sheet mounted to the underside of the floor will help keep heat out and resist rust.

Anak · Jul 1, 2015

I have seen that, and thought about it, but I decided to go with some materials that are actually designed for the job: Heatshield Products Armor Exhaust Heat shield for underneath the floor and Heatshield Products Stealth Shield for on top of the floor (under the carpet).

Link 1: http://www.amazon.com/Heatshield-Products-170103-Exhaust-Shield/dp/B0051UP964

Link 2: http://www.heatshieldproducts.com/automotive/heat-shield-and-thermal-barriers/hp-stealth-shield

Yes, they are more expensive than a cookie sheet, but I suspect I will be happier with them in the long run.

I battled exhaust heat issues with my old Suburban for a number of years. I really don't want to go down the same path again. The Bride would put her purse on the floor in the back and her lipstick would melt and make a mess. I will be in the doghouse if I re-create the same sort of situation here.

Demonoid369 · Jul 1, 2015

Well the first one that wraps won't work for the long run as it will rust out your exhaust,
I have the airbake over a very hot running cat(floor board smokes during normal driving) just took the jeep out for nwfest where it was 100 degrees and even with uphill climbs my floor board stayed cool, still warm to the touch but not capable of frying a egg like it did before lol

CarbonXJ · Jul 1, 2015

Johnnie Walker said:
Seems a bit close, regardless of what you do i hear an Airbake cookie sheet mounted to the underside of the floor will help keep heat out and resist rust.

That does seem close. I'll look at my set up when I get home today. I replaced mine with a Walker cat and stainless everything from the header back a few years ago; I don't think it's that close.

Demonoid369 said:
Well the first one that wraps won't work for the long run as it will rust out your exhaust,
I have the airbake over a very hot running cat(floor board smokes during normal driving) just took the jeep out for nwfest where it was 100 degrees and even with uphill climbs my floor board stayed cool, still warm to the touch but not capable of frying a egg like it did before lol

Did you use the right size converter?? I have dual cats on my V8 Ranger and the floorboard barely gets warm with no shield!

Anak · Jul 1, 2015

CarbonXJ said:
That does seem close. I'll look at my set up when I get home today. I replaced mine with a Walker cat and stainless everything from the header back a few years ago; I don't think it's that close.

Thank you. I appreciate that.

This should end up being almost all stainless. Borla header is stainless. Magnaflow cat is stainless. Coupling between cat and muffler is stainless. Dynomax muffler is stainless. I got a stainless tailpipe from Mandrel Bending Solutions. About the only things that will not be stainless will be hardware and hangers. Murphy says I will tear it all up on rocks within a couple of years.

thanasi85 · Jul 1, 2015

A long as its not hitting the underside your good, once you get the rest of the exhaust in with hangers it will hold it all in placed and it shouldn't move enough to hit the unibody. Worst case if you want some more clearance you could bang in the heat shield on top of the cat and close up any gap between the heat shield and the cat if their is any or just grind away some of that metal that's hanging down from the body right above it.

CarbonXJ · Jul 6, 2015

Could not post up a picture - got to get my count up I guess. But I had plenty of room under my Jeep. I could easily pass my hand between the converter and bottom of the body with 1/4" space above and below my hand

Anak · Jul 6, 2015

Thank you for getting back to me with an answer.

I figured I am too close. I am going to take it out to an exhaust shop to have them heat the headpipe up and bend it down a couple of degrees. I will have them run the weld bead around the cat as well. That way I have a receipt for installation. The lack of a receipt is what put me in this situation in the first place. Kali is so messed up.

Digger87xj · Jul 7, 2015

just bend the hanger that is right there attached to the trans mount. Loosen the front joint flange just enough so it can pivot. The pipe should sit about an inch or so over the crossmember. retighten the flange.

Anak · Jul 7, 2015

By front flange do you mean the flange to bolt the header to the head? There is no play there.

If you are referring the intermediate flange that would be present on a factory system that is not an option. The Borla system does not have that flange.

Heating up the pipe and bending it was the solution.

Digger87xj · Jul 7, 2015

i meant the flange where it bolts to the header...it's usually a ball and socket style to allow movement.

moot now though.

md21722 · Jul 7, 2015

Bend the exhaust hanger and/or loosen it up at the manifold to get the right angle. I found it easiest to loosen everything when I replaced my muffler/cat.

Anak · Jul 8, 2015

Digger87xj said:
i meant the flange where it bolts to the header...it's usually a ball and socket style to allow movement.

On a stock style system that would be an option, but the Borla does not allow for that. It is a slip fit of one tube inside another.

I had all the play in the system that I could possibly get and it still had the wrong angle.

How close to the floor is your catalytic converter?

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