Engine and heat dissipation

[c3nturi0n]

hey guys,

with summer coming i'm sure you all have similar challenges re the amount of heat that V10's produce .

I was wondering is there anything that could be done to address this challenge on C6's (especially when using a car for long motorway journeys)? e.g. not an issue per se, but more of a concern that the amount of heat that remains under the bonnet is / could be harmful for rubber/plastic components longer term.

Interested to hear your thoughts/suggestions?

[Jim Haseltine]

During a journey it's not a problem, it's afterwards - Audis have always retained heat (my 1980s Coupe GT would still be hot hours after I'd parked it). All you can really do is plan journeys so that the last few miles are done with little load on the engine (it helps to turbos no end as does following a turbo cool down procedure) and if possible lift the bonnet for a while when you park. Not that it'll have any real effect unless you did it every time you drove the car and maybe not even then.
Mine is 2008 with over 110K on it and (I suspect) wasn't treated too well prior to my ownership but the only pieces that seem to have suffered under the bonnet are the ribbed plastic breather pipes. And the turbos of course, now I've got it apart the RH turbo is coked up the worst of any I've had in 20 years of driving turbo cars.

[c3nturi0n]

thx Jim. I'd echo on your thoughts.

I was thinking should they've done more to dissipate the heat - e.g. fin type openings on the bonnet, heat / air out ducts on the wings etc. Aesthetics aside, it would have helped longer term.

[IanH755]

While it would be an aesthetic nightmare, a vented bonnet is 100% the best option with one vent either side above each manifold (for the car once it;s parked) and a low pressure vent at the front & above the front of the engine (for when it;s driving), at bit like this god-awful CF A4 one from China. However, while I think that even a painted version would look awful, others are entitled to their own opinion on vented bonnets (had one on my R34 etc).



or these C6 bonnets with vents added -

[c3nturi0n]

Cheers Ian... that’s more in line of my thoughts.

I guess side / wing opening is a no go?

[Toady1]

And the turbos of course, now I've got it apart the RH turbo is coked up the worst of any I've had in 20 years of driving turbo cars.

Got any pics of this???

[c3nturi0n]

I'd be keen to see it too .

[Jim Haseltine]

I think the only piece I haven't cleaned completely yet is the heat shield and that's been soaking in solvent for a day or so. As the carbon was several mm thick in places there's probably a fair bit left so I'll see if I can post a pic later.

[Doug_RS6]

I thought about having louvres stamped into the original bonnet. Perhaps inverted so they went down rather than sticking up.

[c3nturi0n]

I thought about having louvres stamped into the original bonnet. Perhaps inverted so they went down rather than sticking up.

That'd be cool...

[Doug_RS6]

Would look fairly subtle.

[IanH755]

While it might be great for cooling the negative is that it would let water drain onto the hot engine, turbos and electrics whenever it rains unless you cover it when parked. I had an R34 with a vented bonnet and had to replace the vicous fan, air con rad and silicone seal the back of several plugs after nearly 2 months of water related issues.

[Jim Haseltine]

the only pieces that seem to have suffered under the bonnet are the ribbed plastic breather pipes.

And the servo hose. To be more specific, the two plastic pipes of the Y shaped inlet/vacuum pump/servo assembly #4 here. Which might explain why my brakes seem to have no servo assistance first thing in the morning.

[cammmy]

Is the RS6 bonnet the same as the C6 A6? If so, I'm thinking about picking one up and experimenting. Don't fancy hacking up my only bonnet.

On the Cooper S, I added vents near the top mount in the hopes of helping flow through it. I haven't measured IAT but anecdotally, the rad fan doesn't kick on nearly as much when idling/at low speed.

[welwynnick]

Is the RS6 bonnet the same as the C6 A6? If so, I'm thinking about picking one up and experimenting. Don't fancy hacking up my only bonnet.

According to SSP431 all the side panels were changed on the RS6, but not the bonnet, so I suppose that means it's the same as the A6.