Exhaust Manifold Heat Insulation

[Steve P]

Has anyone fitted a SS Manifold and not used heat insulation?

 

Thanks

Steve

[TR NIALL]

Yes and no problems.

[RobinTR6]

Yep, made a heat shield for the starter out of ali from Band Q and no probs. They do get mighty hot tho so limited fiddling under bonnet on that side when engine has run even for a few mins.

[Steves_TR6]

Yes, and no heat shield either.

 

My only problem seems to be fuel vaporisation when the car is parked overnight after a good blast.

It then need a bit of turning over before it fires.

 

Steve

[Lee Sellars]

Hello

 

Just insulated mine on my Rally car and have 25ft spare if you want.

 

Lee

[Steve P]

Morning Lee,

PM sent

 

Steve

[TR6_PI_1969]

Hi,

Has any of you used one of this on an original manifold? Sold by Moss.

Many thanks on your feedbacks

William

[TR6_PI_1969]

And also of these, so in the boot or above the crossbox silencer? 

Thanks!

[DaveB66]

Hi - I've fitted a Phoenix 6-3-1 manifold without any heat protection last year and no problems with it, including playing in the Alps at the end of last summer and long blast on the Autobahns at speeds well over the UK limit.

[TR6_PI_1969]

Thanks Dave!

[JochemsTR]

On 9/7/2013 at 5:43 PM, Steve P said:

Has anyone fitted a SS Manifold and not used heat insulation?

yes, Phoenix 6-3-1.....in combination with ZS Strombergs and now EFI....

[Z320]

Hi,

the isulation makes the exhaust manifold hotter.

This can cause cracks on the original cast irion manifold.

My TR4A is without isolation, without heat shield, without any problems.

Ciao, Marco

 

[john.r.davies]

I wrapped my mild steel tubular manifold in glassfiber tape.   Didn't notice any less heat under the bonnet.

But when I came to unwrap it - new engine and the wrapping ws getting tatty, the metal underneath came off in sheets!   Thin layers that just fell off.     No idea what had happened - corrosion, with heat and low oxygen?   If this applies to S/S I don't know.

JOhn

[TRseks]

Fitted SS exhaust some years ago. Had problems with fuel being too hot on very hot days creating vapor lock, so fitted a heat shield under the carbs, wrapped the starter and covered the metal fuel line to protect from the heat. I left the manifold itself unprotected. No problems the last two summers so it seem to be working, but the last few summers have not been very hot so it might still happen, I guess modern fuel is to blame as well.

The heat shield is 0.9mm alu, two pieces mounted with an air gap of a couple of mm in between, plus two sheets of heat shield material, one between and one glued to the underside.

Magnus

Edited March 5, 2020 by TRseks

[TR6_PI_1969]

Hi! Interesting points, thanks! 

Any improvement noticed on Pi cars with the insulation in the boot? I mean for the injection, anything which reduces the fuel temperature is good for our cars, right?

William

[roy53]

I had problems when i fitted a standard s/steel system , The spare wheel tyre started to stick to the floor and I also had pump problems. I had fitted the rear box as high as possible to help ground clearance but had to lower it as s/steel retains a greater heat. In the boot floor i used the pads that plumbers use to protect the tyre and hopefully hold back the heat. All worked out fine .

Better option or as well as would be to fit a heat reflector padding to the underside of the boot floor.

 

ROY

[Waldi]

1 hour ago, john.r.davies said:

 

But when I came to unwrap it - new engine and the wrapping ws getting tatty, the metal underneath came off in sheets!   Thin layers that just fell off.     No idea what had happened - corrosion, with heat and low oxygen?   If this applies to S/S I don't know.

JOhn

Hi John,

carbon steel cannot be used in oxidizing environment (like air) at temperatures above 400-450 degrees C. That threshold is for good quality grades, as used in process industry. An automotive aftermarket system may be of a lesser quality. Above that is will suffer from several degradation mechanism, oxidation, carburization and creep. Time and temperaturen accelerate this. 

The differences in thermal expansion between head and manifold increase, which can be an issue on cast manifolds in particular. 

Lastly, the gasket temperature will increase, especially when the insulation starts closely to the head, which promotes oxidation of the graphite.

I would not wrap an exhaust, also not a SS one when in use for daily traffic. But I know it is done by the racer boys where duration is shorter. An aluminium deflector would be my preference.

Waldi

[john.r.davies]

Thank you Waldi!  Certainly, I've never bothered to wrap mine again.

The big race boys will ceramic coat their exhausts, but this is just one small component in an incremental approach to performance.   It certainly doesn't provide a big difference!

[TR6_PI_1969]

3 hours ago, roy53 said:

I had problems when i fitted a standard s/steel system , The spare wheel tyre started to stick to the floor and I also had pump problems. I had fitted the rear box as high as possible to help ground clearance but had to lower it as s/steel retains a greater heat. In the boot floor i used the pads that plumbers use to protect the tyre and hopefully hold back the heat. All worked out fine .

Better option or as well as would be to fit a heat reflector padding to the underside of the boot floor.

 

ROY

Thanks Roy, that's the kind of issue I want to avoid with my Pi. Actually with a twin box sports exhaust, I am planning to go back to the mild steel crossbox. Even if not stainless steel, I may try to isolate the boot, it can only be better, isn't it? At the moment with the Twin box sports exhaust, no heat issue in the boot, maybe because the Twin box is a bit lower than standard crossbox? ...

William 

[TR6_PI_1969]

3 hours ago, Waldi said:

Hi John,

carbon steel cannot be used in oxidizing environment (like air) at temperatures above 400-450 degrees C. That threshold is for good quality grades, as used in process industry. An automotive aftermarket system may be of a lesser quality. Above that is will suffer from several degradation mechanism, oxidation, carburization and creep. Time and temperaturen accelerate this. 

The differences in thermal expansion between head and manifold increase, which can be an issue on cast manifolds in particular. 

Lastly, the gasket temperature will increase, especially when the insulation starts closely to the head, which promotes oxidation of the graphite.

I would not wrap an exhaust, also not a SS one when in use for daily traffic. But I know it is done by the racer boys where duration is shorter. An aluminium deflector would be my preference.

Waldi

Understood, I will not wrap the manifold for my use

[PodOne]

6 hours ago, john.r.davies said:

Thank you Waldi!  Certainly, I've never bothered to wrap mine again.

The big race boys will ceramic coat their exhausts, but this is just one small component in an incremental approach to performance.   It certainly doesn't provide a big difference!

I've had Zicotec ceramic coat cast iron exhaust/turbo manifolds in the pasts and it does make a difference to under bonnet temps. I think with the TR with the inlet above the exhaust there might be some mileage in using a an 4mm insulating gasket for each throttle body and a ali heat shield to keep the inlet temps down as this makes a bigger difference to the point I could quite happily put my had on the plenum after a good few laps and esp for road use.

Or I could be just trying to apply Turbo principles to a 50 year old car where it will have no impact! 

Andy