Red hot exhaust manifold

[Mildman]

Hi all....got a little problem.

Last night took the Skyline for a good boot, for about 3km or so. Popped the bonnet as soon as I stopped and the exhaust manifold was glowing a very bright red....around 800-900 C I assume. (I have an infrared temp gauge and the temperature was well if its scale (max 500C).

The bit of manifold glowing is the part you can see between the engine block and the cover over the turbo.

So now I'm a little concerned...I advanced the timing as much as I could and the problem has alleviated a bit....but the exhaust is still glowing everytime I pull up.

Any ideas? I've run out of simple fixes.

[nismoman18]

they tend to glow red when u give the car sum stick, its pretty normal! my friend always gets his extractors red hot on his honda.

[Mildman]

Hmmm..

Might have to research further...but even under reasonably normal driving I've been getting 'the glow'.

My initial instincts is that the car is running lean for some reason.

My other worry with the glowing exhaust is there is plently of piping in the vicinity, particularly the rubber power steering hoses.

[Demon Dave]

I'm pretty sure glowing extractors is normal after a spirited run - have you seen this mpeg of a run on RH9.com.au? Just a quick dyno run and the extractors were glowing like a xmas tree on news years eve!

RH9

[Mildman]

Hmmm, maybe I don't have anything to worry about given the video evidence.

I have access to a dyno and will put it on the dyne in the next week or two and put an AFR meter up its arse.

Obviously without the CAT in action.

It the air-fuel is fine, I'll be more than happy.

Thanks for putting my mind at ease...a bit anyway.

[hyper knight]

g0t hot exhaust manifold!!!

[Mildman]

And the turbo survives that kind of punishment? Ouch

[EVOIV]

Pretty amazing huh? Yeah when I had my car dynoed the manifold started to glow red (stainless steel). It was polished but ended up turning a gold colour after glowing red. Quite normal so I think you have nothing to worry about.

[Hawker180]

my exhurst manafold was glowing red hot....then i found out it was running too lean and it blew a hole in the pistons

if i were u id take it to get tuned...to get more fuel into it...cos mine blew and i had to buy a whole new engine ...wasnt fun at all

[Lunatic Dancer]

also advancing the timing past stock isnt going to help it cool down hehe....

[Mildman]

Well I was just thinking if it was too retarded, the bang is coming way to late, ergo none of the explosive force of combustion is used up in moving pistons, plus the volume in the cylinder is a fair bit higher....creating lean like conditions, resulting in a hotter exhaust gas.

That was my dodgy theory anyways.

Advancing it caused combustion to happen earlier, using more energy resulting in less heat.

How does all that sound...plus I wanted to advance the timing anyway as it was feeling a little lethargic

[tigermm]

Hi, the manifold will always glow a bit at night even after a light run. This is just becuase there is less ambient light so you can see it better.

I would only get worried when you can see it during the day!!

Your 'dodgy theory' is spot on too, more energy used in the combustion process means more power and less exhaust temp. Of course there is more heat inside the combustion chamber, which is why it detonates easier.