Header to Oil Pan Heat Shield - Some Success

[pgilliam1]

NSX OEM exhaust has a heat shield where the exhaust goes under the oil pan, my headers did not. I was told here not to be concerned about it and that it didn't cause problems. I found that to be true because my engine temp stayed steady on the center hash mark on the guage even when tracking the car. I couldn't get passed it though because I know oil temp is important and in the back of my mind was a heat transfer from my headers to the oil pan to the oil. So, I had to try something.
I fully wraped the headers (on the outside all the way around) where they pass under the oil pan with exhaust heat wrap using stainless straps to tie the ends.
The result is that now my engine temp runs halfway between the center hash mark (where it ran before) and the hash just below the center mark on the guage. It runs cooler.
I know percentage calculations based on the guage hash marks are meaningless, but my point is that this mod did some measureable good. I got the heat wrap off of eBay for less than $20 (I already had the stainless straps).
I don't know if there's any downside risks (possibly causing the headers to overheat and crack, etc.), I hope not. Maybe an exhuast expert here can shed some light on the downside risks?

 

[ScienceofSpeed]

NSX OEM exhaust has a heat shield where the exhaust goes under the oil pan, my headers did not. I was told here not to be concerned about it and that it didn't cause problems. I found that to be true because my engine temp stayed steady on the center hash mark on the guage even when tracking the car. I couldn't get passed it though because I know oil temp is important and in the back of my mind was a heat transfer from my headers to the oil pan to the oil. So, I had to try something.
I fully wraped the headers (on the outside all the way around) where they pass under the oil pan with exhaust heat wrap using stainless straps to tie the ends.
The result is that now my engine temp runs halfway between the center hash mark (where it ran before) and the hash just below the center mark on the guage. It runs cooler.
I know percentage calculations based on the guage hash marks are meaningless, but my point is that this mod did some measureable good. I got the heat wrap off of eBay for less than $20 (I already had the stainless straps).
I don't know if there's any downside risks (possibly causing the headers to overheat and crack, etc.), I hope not. Maybe an exhuast expert here can shed some light on the downside risks?

The only real downside to these types of wraps is the material soaking with oil from a leak resulting in a fire.

-- Chris

 

[pgilliam1]

The only real downside to these types of wraps is the material soaking with oil from a leak resulting in a fire.

-- Chris

That's a pretty big downside! I thought since the material was flameproof that wouldn't happen . I take it you speak from experience?? YIKES!

 

[OneRedNSX]

The material is flame proof... The oil that would be soaked in it...

 

[shawn110975]

sounds like a great idea if you could find something that could then wrap around the cloth so it could not soak up oil.

or make a custom peice of aluminum to sheild the oil pan from the heat.

lots of potential though

 

[pgilliam1]

The material is flame proof... The oil that would be soaked in it...

I get that, but even oil that pools on an engine doesn't combust, and I've had oil dripping on my headers (in a different spot) for many miles and it hasn't started a fire yet :redface:, but there is quite a bit of smoke (knock on wood). I wonder if synthetic oil has a higher combustion temp ? I'm going to soak a piece of that cloth in motor oil and put it on a piece of metal and heat it with a torch and see if I can get it to burn . Sheesh!

 

[OneRedNSX]

I don't know how hot it would have to get but I have seen it happen on turbo cars with a wrapped downpipe... Maybe it was the excessive heat generated by a turbo but it's still nothing I would want to mess with.

You also did not say what kind of headers you have. Many metals commonly used in exhaust components will rust heavily when wrapped.

 

[Mac Attack]

I wouldn't worry about it getting soaked with oil! You seem to take excellent care of your car and are very observant towards these things. If it is a concern, however, you can always coat your wrap with this silicone header wrap spray to help inhibit oil saturation:

http://www.designengineering.com/category/catalog/design-engineering-inc/exhaust-wraps-accessories/ht-silicone-coating

Really, the only thing to worry about coating just one section of an exhaust header is the extra stress on the header primaries caused by the different temperatures upstream and downstream of the wrap. In the wrapped area, you are now keeping in extra exhaust heat that would otherwise be lost by convection to the underbody airflow (or the oil pan :wink. The areas upstream and downstream don't have the wrap so they'll be at slightly lower temperatures. Also, as RedNSX said, this will also accelerate any corrosion too.

Personally, I wouldn't worry about it. Everything is a compromise unless you have big big $ to spend on things. I have a temp sender in my oil pan - I'll have to wrap that "header" portion on mine to see if it makes a difference. I have RedNSX's old NA2 headers which makes it easy since it's only the collector at that point passing under the pan.

Dave

 

[pgilliam1]

I wouldn't worry about it getting soaked with oil! You seem to take excellent care of your car and are very observant towards these things. If it is a concern, however, you can always coat your wrap with this silicone header wrap spray to help inhibit oil saturation:

http://www.designengineering.com/ca...exhaust-wraps-accessories/ht-silicone-coating

Really, the only thing to worry about coating just one section of an exhaust header is the extra stress on the header primaries caused by the different temperatures upstream and downstream of the wrap. In the wrapped area, you are now keeping in extra exhaust heat that would otherwise be lost by convection to the underbody airflow (or the oil pan :wink. The areas upstream and downstream don't have the wrap so they'll be at slightly lower temperatures. Also, as RedNSX said, this will also accelerate any corrosion too.

Personally, I wouldn't worry about it. Everything is a compromise unless you have big big $ to spend on things. I have a temp sender in my oil pan - I'll have to wrap that "header" portion on mine to see if it makes a difference. I have RedNSX's old NA2 headers which makes it easy since it's only the collector at that point passing under the pan.

Dave

Excellent advice. I just bought a can of the silicone on eBay - THX.

My headers were installed by a PO at RM Racing in Scottsdale, AZ (now defunct). I haven't a clue what kind they are. My wrap stops before the collector and allows airflow through the wraped area.

I'd be interested in your findings on oil temp after you try the wrap.

Thanks Again and Happy Motoring!

 

[g3driver]

Excellent advice. I just bought a can of the silicone on eBay - THX.

My headers were installed by a PO at RM Racing in Scottsdale, AZ (now defunct). I haven't a clue what kind they are. My wrap stops before the collector and allows airflow through the wraped area.

I'd be interested in your findings on oil temp after you try the wrap.

Thanks Again and Happy Motoring!

any update on this? Did your oil temps go down?

 

[pgilliam1]

any update on this? Did your oil temps go down?

My engine temps (based on the OEM guage) went down 1 full guage mark and have stayed down and steady. Mac Attack was going to wrap his headers and, since he has a temp sensor in the oil pan, he'd be able to get a more precise reading. I have checked my install after spraying with the heat rated silicone spray and have found no problems - yet. So far I am glad I did it and would recommend doing this header wrap.

 

[Jeff@Carbon6]

I'm looking at wrapping my headers and then going over the wrap with a silicone tape. That would protect the wrap material from wicking any oil and make them easier to keep clean. The silicone tape should take temps of +/- 300 deg. The surface temp of the wrap should not exceed ~250. My buddy works as an engineer for military trucks and he said they did that on a few vehicles with great success.

 

[BATMANs]

For the amount of money some of ya'll dole out for tracking events/lifestyle ya'll should just ceramic coat the headers and apply thermo dissipation coating on the oil pan.

I did.

 

[RYU]

What's interesting is that even with the NA2 headers that has a built in heatshield, water and oil temps are still a problem for tracked NSXs.

Thanks for providing your feedback though. I'm willing to give it a shot.

 

[Grimeas]

I thought i remember seeing and hearing that these wraps will also get wet and end up corroding the header.

 

[pgilliam1]

I thought i remember seeing and hearing that these wraps will also get wet and end up corroding the header.

I'm hoping the silicone coating will prevent it and also the heat from the header dries the wrap off fairly quickly. So far, so good.

 

[pgilliam1]

For the amount of money some of ya'll dole out for tracking events/lifestyle ya'll should just ceramic coat the headers and apply thermo dissipation coating on the oil pan.

I did.

Both good options, but for $20 and 20 minutes the wrap was too simple not to try.

 

[BATMANs]

Both good options, but for $20 and 20 minutes the wrap was too simple not to try.

 

[ScienceofSpeed]

I take it you speak from experience?? YIKES!

Not personally, however, the NASA regional director was recently involved in a pretty good fire in his Civic race car. The header wrap was coated from oil from a transmission line breaking. He was out of the car within seconds of noticing the fire (something that he had practiced for in his caged race car), but still sustained major burns on his face (in his follow up, he regrets not putting on his head sock before going out).

I much prefer the OEM route, which is using insulation panels rather than wrap applied directly to the headers. In addition, ceramic coating outside and inside if it can be done. Obviously, the small leaks on the headers you're talking about is a lot less oil volume than what this driver experienced, but the possibility is there with the valve covers and breather tubes being above the headers.

-- Chris

 

[pgilliam1]

2 really ugly pictures! The NSX engine fires I've read about all were caused by leaky injector seals (I replaced mine soon after reading about that). The original oil leak I had was from a rear cam plug and spool valve and now they're both fixed there's no more oil leaks. I check my oil and engine before every drive, so I'm not too worried about soaking the wrap. An engine fire would really suck! Maybe I'll look into the silicone tape VroooM mentioned.

 

[pgilliam1]

I much prefer the OEM route, which is using insulation panels rather than wrap applied directly to the headers. In addition, ceramic coating outside and inside if it can be done. Obviously, the small leaks on the headers you're talking about is a lot less oil volume than what this driver experienced, but the possibility is there with the valve covers and breather tubes being above the headers.

-- Chris

I'm thinking about pre-fabbing an insulation panel between the headers and oil pan. Shouldn't be too hard, I just hope it's as effective as the wrap when I'm done .

 

[geometro]

Why not take one of the adhesive backed heat barriers and apply it to the oil pan directly above where the header passes under?

 

[liftnot]

Why not take one of the adhesive backed heat barriers and apply it to the oil pan directly above where the header passes under?

I did this on mine and the heat barrier eventually fell apart but left the adhesive on the oil pan. Any other effective solutions besides wrapping or coating?

 

[angus]

I use header paint to coat the wrap, it further keeps heat in and prevents it from soaking up oil.

 

[RYU]

I'm thinking about pre-fabbing an insulation panel between the headers and oil pan. Shouldn't be too hard, I just hope it's as effective as the wrap when I'm done .

Also thinking of doing this as well. I can think of a few different options on how to mount it to the header without welding on tabs. I'll have a look later on since perhaps it can be mounted to the oil pan somewhere else.

The problem is... where to find heat insulating material like the oem heatshields. They are 2-ply. I think any regular sheet metal will heat soak.

This would be an easy product for a vendor to come up with.