Tubular exhaust

[Tonyloz]

Hi all

Just a quick one

Is it a must to unsulate a tubular exhaust manifold to stop heat damage under the bonnet?

Thanks

T

[boxofbits]

Hi Tony

 

Wouldn't have thought so. The heat generated will not increase due to the type of exhaust system you use. The heat should dissipate in the same way as a cast manifold. My 4a has a steel ex manifold and not had any issues, but nothing stopping you using heat insulation.

 

Regards

 

Kevin

[Stevecross]

Tony

 

Pm Rich -( rcrewread) and ask.

 

His party trick is parking his 4A up at a fast idle and getting his tubular exhaust to glow in the dark!

 

Steve

[PeteT]

Hi Tony,

 

The only thing to bear in mind is that a tubular manifold is usually much bigger than the stock item and often ends up much to close to things like electricle connections (Dynamo). I ended up using wrap in one small area and a heat shield in another to keep everything working. Worth the effort though.

 

Regards, Pete

[rcreweread]

Tony

 

In my experience so far, I haven't suffered any noticeable ill effects from heat issues with my Phoenix 4 into 1 stainless steel system, although I have got an alloy heat shield ( from Revington) protecting my alternator ( Dynamator ).

 

I really don't like the look of the exhaust wrap stuff, so if I can avoid using it, I will!

 

As Steve has already posted, it's not difficult to get the manifold glowing cherry red when I'm parked up - just run the engine at 2000rpm for about a minute - obviously the bonnet is up!

 

It's especially spectacular in the dark but I suspect when I'm travelling along, the forced airflow will prevent that from happening - it reminds me of that advert with the Audi RS8 on a rolling road with the back up, with the camera concentrating on the engine and driveline under full acceleration through the gears - the manifolds glow red hot in no time at all , and then cool down as the car decelerates to a stop - the aural impact is as good as the visual!

 

Maybe someone with the necessary IT skills can post the link to the advert on here and you'll see what I mean.

 

I do keep a watchfull eye on stuff in the vicinity like the starter motor and cables, the brake pressure switch and wiring but so far they all look fine.

 

Hope this helps

 

Cheers

Rich

[RogerH]

Hi Tony,

any insulation will not have a great effect on underbonnet temp .

However you must insulate the back of your alternator and possibly consider insulation for the carbs if they give signs of suffering.

 

Having said the insulation has no great effect you will find that with either ceramic coating or wrap the exhaust temp out the back increases quite a bit.

So it must have some effect.

The tubular pipes will give off more heat has there os less thermal lag. Both the tubular and cast manifolds are trying to be cooled by the engine bay air.

The cast manifold tends to deal with it better.

 

The benefit of the ceramic coating (CamCoat or Zirctec) is that the pipes remain in a decent condition for a very long time.

The tractor wrap looks cheap and nasty and a possible fire risk.

 

Roger

[hpremote]

Hi, Tony:

I've had a Phoenix tubular manifold and custom piping on my 3 for ten years and have had no damage problems with underbonnet heat. No wrap or heat shields on my car, but I only have a dynamo; I have heard, as advised above, that alternators may be more vulnerable to the extra radiating heat.

 

Cheers,

Tim.

[Tonyloz]

Thanks for the replies guys

Just dont like the wrap look

As ive stayed with the dynamo ill give it a go naked!

[Graham]

I used to do Rich's trick with BUO but not only did the manifold glow the inner wing glowed red hot as well ! …….not great for the paint

 

ATB Graham