Temperature readings on exhaust manifolds or headers as well as heat wrap help

[Hawk]

I’m trying to get some temperature readings on stock exhaust manifolds and headers from other guys. I recently installed Belanger headers and had them coated with Swain tech white lighting exhaust coating. On a spirited street ride I had temp readings of 390 degrees F, on a 20 minute track sessions I’m getting readings as high as 640 degrees(readings taken on the header close to the connection to the block). I’m less than impressed with the Swain Tech coatings ,I have reached out to them a couple of times on the problem and have gotten no response. I was planning on wrapping the headers has anyone wrapped them in place or should I bite the bullet and remove the headers and wrap them? Appreciate all help
Here is the link to my original post on the header heat shielding https://driveviper.com/forums/thread...ng-for-headers

Thanks
Dennis

[Lawineer]

Coatings don't do much for thermal insulation, honestly. They definitely HELP, and it's not insignificant, but it's not huge. As you've noticed, no the track, they're just not enough. Header wrap, while not particularly aesthetic and slightly dangerous, is much more effective.

This is ~20 years ago (JFC, how did that happen), but when I was doing powertrain development for the S7 TT, emissions were much tougher to meet than today. We had a problem putting the turbos before the cats for cold start because the turbos ate the heat up. We solved the problem by wrapping them. It made a big difference.
But then I'm pretty sure Steve hated it so we took it off and just cheated.



Nerding out: the formula for "conductive" heat transfer (or lack thereof) is basically material property [how well/poorly it conducts heat] * Thickness * difference in temp. When the thickness is so close to zero, it's just not going to do much. By conductive I mean when it's by touch, whether conduction or convection. Obviously, this is very watered down.

Where coatings are very effective is radiant heat transfer, like line of sight. Think glowing charcoals searing a steak in a 500 grill vs a 500 degree oven. Sitting in the sun vs shade (air temp is the same). They can reflect a lot of heat. The "good" window tint is a great example of this. Thickness doesn't really matter for radiant heat insulation/absorption.

Stainless steel with good header wrap (wrapped well) will always be better than any of these ceramic coatings. Obviously, both is better.
The best is the "blanket". Basically, it creates an air pocket around the header/manifold. Now you have huge thickness of air as your insulator. They're malleable reflective sheets with fiberglass inside (probably have better stuff now) and you wrap the whole header in it. Combine those three and you're in pretty good shape.

[13COBRA]

Coatings are cool looking... fairly worthless for track duty.

If you can wrap your headers on the car, I'll fly you out to help me redo mine in a few years haha

[GTS Dean]

Unless your headers are fabricated from stainless, the best things about ceramic coating are scratch and corrosion resistance. You may get some modest heat transfer improvements, but for sustained high load conditions, you need a wrap or a blanket/shield setup. And as some have said around here, you will NOT get a true temp reading on a shiny surface vs one that is matte when measuring with infrared due to the emissivity factor.

[Arizona Vipers]

Wrap them. Probably the best mod you can do for the money. Send that heat out your sidepipes, get it out of your engine compartment. Your car will pull so much less timing during your sessions.
There is absolutely no reason to not wrap them, it shouldn't even be up for debate imo. If they corrode in 10 years and you have to replace them so what. My headers are 6-7 years old now, wrapped for at least 5. We rewrapped them a few months ago and they looked fine, no corrosion. There is also the argument that they could catch fire if you let oil build up on them, so keep an eye on that. I've never had an issue.

[Hawk]

Coatings are cool looking... fairly worthless for track duty.

If you can wrap your headers on the car, I'll fly you out to help me redo mine in a few years haha

I guess wrapping them in place is wishful thinking, dreading pulling them out and reinstalling them. The only good thing about the swain Coating is that it has small bb sized chunks that raised thru the hi-temp. paint is it will probably hold the warp in place well

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[GTS Dean]

Woven tape wraps are not always the most user-friendly option for installed exhaust systems. Have a look here: https://motoiq.com/project-viper-gts...ield-products/

[nwa_viper]

Aren’t the Belanger headers mild steel? I don’t think you want to wrap them. I bought ARH because they are stainless and wrapped them.

[Dan Cragin]

I found that ATP inconel header shields worked best. The wiring under the hood never got crispy and the shields have and air gap between the header
which reduces heat transfer.

[Hawk]

I know I’ve been beating this subject like a dead horse. I have the Swain Tech coating and installed DEI Titanium heat wrap on the headers and collector pipe. After a 20 minute session I am getting temp readings of 570 degrees on the headers (drivers side) and the collector pipe measures 610 degrees. I had the stock heat shield that separates the pedal area of the car from the collector pipe a solid 3”-4” away burn up on the back side of the foil to the point it looks like it was smoldering as well as the DEI heat sheathing cook the foil off the top of the covering (these are also 3” away from the collector). These products are rated for 500 degree direct and 2000 degree intermittent. Are the Belanger headers I bought not meant for track use and are building too much heat because of a poor design or is the flange are that is not wrapped generating that much heat? What type of header are you track guys running? I’m ready to toss the headers in the trash and reinstall the stock exhaust manifolds! Hoping someone can shed some light on what I’m doing wrong.
Thanks
Dennis
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[GTS Dean]

No offense meant - seriously - but like Dan says, I think you'd be better off with some air gap and1200F direct contact rating stainless/ceramic batt sandwich type shields instead of direct contact wrap of lower rating. Let the tubes get hot, but protect sensitive wiring and frame/body components from the radiant heat. If nothing else - it's a heck of a lot easier to apply than wrapping tubes - especially if they are already installed in the car. I've seen melted & burnt Vipers for 25 years because people either don't insulate at all, or not effectively. I run the piss out of my car at the track and exhaust temp effects are managed very well.

[Hawk]

No offense meant - seriously - but like Dan says, I think you'd be better off with some air gap and1200F direct contact rating stainless/ceramic batt sandwich type shields instead of direct contact wrap of lower rating. Let the tubes get hot, but protect sensitive wiring and frame/body components from the radiant heat. If nothing else - it's a heck of a lot easier to apply than wrapping tubes - especially if they are already installed in the car. I've seen melted & burnt Vipers for 25 years because people either don't insulate at all, or not effectively. I run the piss out of my car at the track and exhaust temp effects are managed very well.

I’m going to give the batts/blanket material a try. I just cant figure out how other guys are having luck with the header wrap and the coatings? The problem area is the small collector pipe between the base of the headers and the 90 degree elbow where it turns into the side sills. Do you think I would have to remove the heat wrap before installing the heat blanket material or go right around it with an air gap at the bottom? I noticed the Belanger headers had a large spiral metal cone in the center on that section of pipe is it possible that is creating the excessive heat buildup in that area ?

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[ViperGeorge]

This is very weird to me. My friend and I both have 9 Liter Extreme engines from Prefix with ARH headers and Swain coated. We measured temps on the primaries immediately after coming off track (like a 25 minute session) and were blown away at how "cool" the primaries were. Nothing over like 170 which is stupid cool. We checked multiple times.

We also have a friend that Swain coated his headers (Bellangers I think) on his Gen 2 and coming off the track at Hastings during the Viper Rendezvous (and it was hot out) he could put his hand within a couple of inches of the primaries. I could never have done that with the uncoated Bellangers on my Gen 4 or my previous Gen 5. My hand would have blistered from the heat. To me the Swain coating was one of the best things I've done.

[Lawineer]

How is your tune? If you're running rich, your exhaust primaries will be very hot.

[ViperGeorge]

How is your tune? If you're running rich, your exhaust primaries will be very hot.

I think this is a very good point. I remember reading somewhere that Prefix (ie. Dick Winkles) leaned out the tune for the 9 Liter. The stock tune tends to run rich and get richer as the engine gets hot.

[Hawk]

I have the Prefix PMC

[ViperGeorge]

I have the Prefix PMC

Well this is a mystery then.

[GTS Dean]

I wonder if you might have some downstream restriction that is contributing? Do you still have cats? If you have metallic substrates and they melt, or ceramics fall apart, they can become restricted and that heat has to go somewhere, so it radiates. The tune may have contributed to it? I'm going to leave those details to the Gen V group.

[Hawk]

I have the cats that came with the headers. I called Belanger today and ordered the mid pipe that replaces the cat, I’m hoping I can get Lew Belanger on the phone and shed some light on what could be going on. I also left a message at Prefix to see if my control module could be doing something goofy. I just finished dissembling the muffler, cats and collector pipe and I noticed that the lock washers on the collector pipe are now flat and no longer have a spring to them , that’s got to be some serious heat I’ve never seen that happen. I’m wondering if there could be something wrong with the cats possibly a bad batch? The car only has 12-20 minute runs on the headers and cats and I’ve been battling this from the first run. I must have lottery luck in a bad way ☹ But the car is running great so I'm baffled

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[ViperGeorge]

I have the cats that came with the headers. I called Belanger today and ordered the mid pipe that replaces the cat, I’m hoping I can get Lew Belanger on the phone and shed some light on what could be going on. I also left a message at Prefix to see if my control module could be doing something goofy. I just finished dissembling the muffler, cats and collector pipe and I noticed that the lock washers on the collector pipe are now flat and no longer have a spring to them , that’s got to be some serious heat I’ve never seen that happen. I’m wondering if there could be something wrong with the cats possibly a bad batch? The car only has 12-20 minute runs on the headers and cats and I’ve been battling this from the first run. I must have lottery luck in a bad way ☹ But the car is running great so I'm baffled

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Boy, they must be hot. The wrap looks crispy.

By the way, I am running "Green" high flow cats from ARH. The "Green" cats are an upgraded 4 cell cat from ARH. The two cell ARH ones that came with the headers bit the bullet and I hated the smell. Without cats be prepared for exhaust smell. It can be noticeable given the side exhausts.

[Lawineer]

Something is up. Timing or AFR or plugs or something.
I doubt it's a clogged cat simply because it's noticeable likely throws a code.

Get that car on a wideband.

[Hawk]

The exhaust smell will be welcome over the burning wires and heat shielding! Would you recommend keeping the cats, I was hoping to keep them but if this is the cause they will need to go
The heat wrap was black it cooked most of the color off and it turned to the natural color, this wrap seems fine it’s the shielding on the car body pan and wires that is cooking
Thanks
Dennis

[Lawineer]

removing the cats is a band aid. There's another reason your exhaust is this hot.

[Hawk]

removing the cats is a band aid. There's another reason your exhaust is this hot.

I agree with you, any thoughts on the plugs? They don’t look like they’re running rich.
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[Steve M]

Plug looks just fine to me.

If it was a rich condition, I'd expect to find evidence of that in the header primaries as well. Are they toasty, or just when it gets close to the cats?

Based on the evidence presented, I'd suspect the cats too...most don't stand up to extended track abuse for very long, and given the unknown source for Belanger's cats, I'd look there first.

I will warn you: questioning Lou directly might not yield the best results. My one and only conversation I had with him many years ago wasn't the most pleasant, but in the end, I got what I wanted. Which I can assure you, was counter to his advice.