engine & exhaust really hot?

finny_quattro

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since i bought the car i noticed it gets pretty hot although both fans do kick in even after the car only been running for 10-15 mins it will be really hot! i was told this could be down to the cats? the back box even gets pretty hot....is this actually normal or not? ive just had a full service so obviously coolant has been done but still the same?
 
Define hot... hot as in over 90 degrees on the dash or hot as in hot in general? Turbo cars get firkin hot... exhaust temps can reach over 900 degrees and the exhaust mani will glow bright red when given the beans... stainless steel exhausts will actually grow when hot... mine pokes out at least another 15mm or more when I have driven the car 'enthusiastically'

When on the dyno the other week I had the AFR probe clamped onto the tail pipe with a bit of cardboard to prevent marking the tips and it caught fire from the heat...

<tuffty/>
 
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Im gonna cook some eggs on mine or warm up a pasty :)
 
Check your oil and coolant to be sure
 
ive always said i thought the under bonnet temps on these things were unhuman
 
well double ester extra virgin swiss olive oil would be best
 
ive always said i thought the under bonnet temps on these things were unhuman

I agree, even with the heat proofing, rubber strip cut out and front grille cut out, it's still extreme under my bonnet.
 
My mate is making me some spacers to raise the back of the bonnet about an inch. Will put my temp sensor under the bonnet before and after to prove concept.
 
My mate is making me some spacers to raise the back of the bonnet about an inch. Will put my temp sensor under the bonnet before and after to prove concept.

Yeah be interesting too see that result Welly.
 
My mate is making me some spacers to raise the back of the bonnet about an inch. Will put my temp sensor under the bonnet before and after to prove concept.

Cough *CHAV* Cough :), haha. On a serious note though, would be good to see how much it helps lower the temps.
 
i noticed a difference (but didnt use temp probes) just by removing the rubber strip from the back of the engine bay
 
Yep, thats gone on mine - the only issue being that I get the smell of heat in the cabin, as it comes up and into the pollen filter.
 
Have you tried cutting out the plastic behing the upper grille? i did aswell as removing the bonnet heat proofing and cutting the rubber strip at the back, works a treat, plus the DV is louder :).
 
sadly welly, I don't think your idea of raising the bonnet will work at all.

From aero testing done on minis, it was shown that there was actually higher pressure at the back edge of the bonnet where the screen goes up, and a result, gases were actually drawn INTO the back edge of the bonnet rather than escaping!
 
sadly welly, I don't think your idea of raising the bonnet will work at all.

From aero testing done on minis, it was shown that there was actually higher pressure at the back edge of the bonnet where the screen goes up, and a result, gases were actually drawn INTO the back edge of the bonnet rather than escaping!

That's most interesting actually dude, you any links to data? Would be an interesting read, I love things like that.

Anyway, two reasons I will be doing it still....

Now I've given this some considerable thought, the interesting thing is the slightly upturned lip at the back of the S3/A3 bonnet. In my mind, air rushing over....

Sod it, I'll draw a diagram...

bonnettheory.jpg


That's my basic theory of how it would work, which is why I'd be grateful for any info you can pass on Prawn :thumbsup:.

Secondly, the majority of my heat build-up under the bonnet comes from giving the car a bit of beans, and then stopping. Now stopping being in traffic, or whatever, means that when I get going again, the UBT has gone up by many degrees from the heat of the turbo, heating the air up.

Raising the back of the bonnet up will at least allow the air being heated by the turbo to vent straight out through the gap, as it naturally will. I have proved this as a concept by removing the rubber strip at the back, and watching the heat coming out whilst stopped at traffic lights or the like.

Hopefully, this will greatly aid the effort to keep under the bonnet cooler, as the hot air is not being trapped after being heated by (a normally glowing) turbo...

Thoughts?
 
thats how my "take out the rubber" bit system goes
 
well thats alot of worry off my mind....i just noticed the whole thing was boiling..although temp gauge is perfect at 90 when i take the engine cover off etc its hard to even touch the back of it lol but hey if its normal who cares il just wait until its properly cold

cheers lads
 
If the front of the bonnet was raised slightly as well, I think it would help immensely as would create a wind tunnel type affect (i'm sure theres a technical term so insert here).
Now raising the whole bonnet up an inch or so, I think would look *****, but if you could direct a cold air type feed to blow across the top of the engine bay think you could be onto a winner!
(The main principle would be similar to a fan blowing across a heatsink, only airflow is the fan and the engine the heatsink)
 
Welly, love the pic. Whats even better is i love the fact you have labelled the CAR, i was wondering what it was lmao.