Brentis

Has anyone had experience using exhaust wrap? I seem to remember a lot of mkiv folks using it for their downpipes. Not only does it cool the engine bay, but the keeping the "hot inside" actually accelerates the speed at which the exhaust gases exit - increasing horspower, spool, etc.

Here's a link with a few flavors.

http://www.optauto.com/webstore/depa...=855&last=1431

I know folks have used jet-coat with varying degrees of improvement but I have to think a wrap would be better...

large_x7

iTrader: (1)

i have exhaust wrap on my dp that i bought from JEGS. i don't know about hp cause i've never dynoed, but it certainly cooled down my interior. a lot less complaints from passengers with feet that are too hot!

GoRacer

iTrader: (2)

I don't beleive heat wrap is better considering that heat coating is done both on the inside and outside and there is no way for moisture to get trapped in between the coating and the pipe. Jet-hot rates there 2000 coating to withstand 2450 degrees. I don't know what the tape rates, doubt that much. Coating is $60-$63 and a roll of header tape is $40-$60, isn't it?

Brentis

that is pretty cheap. your right about the costs. tape is rated up to 2000 degrees.

RonKMiller

I don't think that condensation on the outside of the pipe using heat wrap is a concern, since it is such a large open weave pattern. It does look a little "cobbled" though, with the tape instead of a nice smooth pipe.

You can buy heat wrap by the foot, and I think it took about 12 feet of 2 inch wide to wrap my dp, about $20, plus a couple of metal zip ties.

I think the Jet-hot is a great product, but $60 for coating and UPS both ways gets expensive. Make SURE you stick a bolt in the O2 sensor hole and that it extends all the way into the pipe before shipping it so the threads don't get coated.

fdracer

ron,
are you sure it only takes 12 ft. for the dp? i'm gonna buy some heat wrap and don't wanna end up buying too short of a length and having to get another one shipped. on the other hand and i don't want to buy too long of a length which i won't need.

RonKMiller

No, I don't remember for sure. Call a local hot rod shop with the diameter and length you are covering. They should know, and then.......but a little extra for insurance. One extra tibdbit for what it's worth: I've been told NOT to cover the head of the pipe since it is possible to crack the casting/flange/welds from heat cycling. I zip tied my OEM heat shield back in place with an extra long metal tie to hold it in place. The way I figure it, this would allow the head to get hot, yet still allow air to cool it, as well as protect the pipe and wires nearby on the fender/firewall. When I tied the ends of the wrap I turned them under about a half inch or so to give it a "hem" and hide the fraying that is unavoidable when you cut it.

fdracer

anyone know the length and outside diameter of the dp offhand?

13brv3

The biggest concern I'd have with this wrap is fire. If oil leaks on a pipe after shutdown, it only gets a small coating, and the excess drips off. This wrap would soak up a bunch of oil, and would be more likely to start a fire. Maybe I only worry about this because my car leaks like a sieve

Cheers,

skunks

i got 8 layers on my DP and after a hard run, i can actually grab the dp with my bare hand and ti just feels warm to the touch

and as for rusting, ill just buy another dp later if need be, by then ill need a new engine. in anycase, i doubt that rust is even an issue here.

GoRacer

iTrader: (2)

Typical diameter is 3" and length is 3'.

Jet-Hot is not the only company that heat coats bu they are the only ones that rate their 2000 degree coating up to 2450 degrees.

Most of the heat coat company's will no longer only coat the outside because it doesn't protect the part and they can't warranty their coating.

Here is a quote from: performance coatings (<-link)
Unlike header wraps, ceramic coatings do not hold potentially damaging heat & moisture around the part. Rather, the surface temperatures are actually reduced, extending the life of the part. When cured, a very effective corrosion inhibiting film is formed that protects the part against oxidation and imparts excellent chemical resistance that further extends part life and enhances appearance.

RonKMiller

There's only two things in life I am scared of: lightening and an on-board fire. Make that three: double bogies.

Damn dood, fix that leak! If you've got an RV3 you certainly can find that sucker and fix it ASAP.

I helped build TWO Long EZ's a few years back........
One took Grand Champion Plans Built at Oshkosh.
We were dumbfounded. The upholstery was mediocre but it flew like a homesick angel on steroids. We even made the prop.

Kits? We don't need no stinking kits!
No more S-glass for me, never, ever again - back to rivets

RonKMiller

I believe it. Ceramic coatings are awesome. I just can't swallow the price differential for such an inexpensive pipe. I have an issue with most so called high tech applications because 90% of them are pure marketing bullshit.

If you have the $, I say go with the coating, but for a car that is 10 years old? (mine)

The other issue is: if it is a quality stainless dp, corrosion is not ever going to be an issue, ditto heat reducing the life of the part. You want the sonamabeach to get hotter than hell to promote scavenging.

Skunks: 8 layers? , that sucker must look like a Mummy!

13brv3

Yep, this weekend, I promise. The main leak is a motor mount, and I have all the cleaner and sealer ready to go.

FWIW, I'll certainly be using performance coatings for my RV-3 exhaust. They don't like to hear the A word (airplane), so you have to tell them it's an offroad vehicle, or a boat. Lot's of these places won't sell to you if you tell them it's for a plane. For some reason, they think there's some huge liability that goes along with planes. Silly people, it's not like it's a certified plane carrying commercial passengers.

You sure you won't build my custom cowling :-)

Cheers,

RonKMiller

Umm, NO.

Three things I won't even attempt: cowlings, prop spinners and canopies. Especially not the hors d'oeuvres type. I actually buy that stuff from the REAL experts.

Keep the shiney side up!