HAVE IT COATED FOR $60.00
 

Got mine done a week and a half ago. Ceramic based coating inside and out in a 2000 degree aluminum color. It looks good and puts out a hell of a lot less heat than the stock precat. PERFORMANCE COATINGS - give Brad a call - 1-253-735-1919. I took it in on Tuesday and they shipped it back for a Friday delivery.

Wrapping is bad because it retains moisture. I posted a link to the article in another thread. There are plenty of company's that can heat coat your DP. Notice I didn't say jet-hot your DP! ...it's "heat coat". $100 shipped and coated both ways and in-n-out. Warranty only if new.

Actually you want the exhaust gas to cool as rapidly as possible once it leaves the turbo exhaust scroll. That's because gas contracts when it cools, reducing back pressure on the turbine wheel. However, you can also reduce back pressure with a larger diameter DP. In my case I used a stainless steel DP and wrapped it. The ID of the pipe is considerably larger than the pre-cat pipe ID so one thing probably canceled out the other.

The other consideration is that the cat converter (assuming you have one) needs high temps to operate properly, so wrapping the DP helps keep EGT higher until it hits the cat.

I think I would do ceramic coating over wrapping...Looks better too :D

Well,

This is a very long thread. I say wrap, Ok now thats over. For the record I have a used stainless pipe. I used summit wrap and so far I only heard one person mention that the manufacturer said to spray the wrap to prevent rotting. I can't remember the brand I bought, (I bought the recomended paint and sprayed the whole thing). I can say that I recently after about six months of running the wrap removed my down pipe. That I did spray mine with the recomended spray. (looks silver and sticks to everything) I found that the regular screw type clamps I used to hold the wrap were not discolored in any way (clamps were not painted) and get this, I used regular masking tape to hold the wrap on during painting. The masking tape was burnt at the very edge of the flange at the Cat, but perfect on the wrap that should tell you how effective it is. I could not tell any difference in color of the wrap or paint from the day I put it on. I think the paint will handle any condinsation problems anyone may be concerned with. I think that ceramic coatings are great. I'm just impaient and like to get the most out of my money. It leaves more for other mods!

Terry7

I wrapped my Pettit SS DP when I installed it 4 years ago and then oversprayed the wrap with the VHT aluminum high temp exhaust paint (made for wraps). I bought it all from Summit. It has given my no trouble at all and the DP is not rusting at all. Naturally, however, the mild steel flanges are rusting, blech. That would happen regardless of wrap or no wrap anyway.

-Kib

A catalytic converter requires a certain operating temperature to performance properly. Excessive temperatures will reduce cat efficiency and possible reduce operating life. Has anyone with a wrapped downpipe experienced 1.) problems passing smog tests, and/or, 2.) accelerated degradation of the catalyst bed?

I wrapped my stainless steel DP and I will be wrapping my mid pipe asap..