Heat soak reduction on the C6 S6 Manifold

A6 All/ S6 All
#1

I’ve been thinking of the best way to try and reduce the heat soak which occurs in the S6’s engine bay.

We’re sure the best way to do this is to have a more efficient and effective exhaust header system, which doesn’t PURPOSELY get really hot really quickly.

But, can we do anything on the intake side which would have a noticeable effect?

Firstly, read justincredible’s thread here: http://audirevolution.net/forum/index.php?topic=2721.0
(nice work, mate)

We can see that the spacers do have an effect - but do we know whether this is more because the manifold has been moved further from the block (reduction in radiant heat), or because the manifold has been thermally decoupled from the heads (conductive heat)?

I would tend to think it’s the latter - but we also see JHM using reflective heat tape to further drop intake temps.

I had another idea - what if the valley between the heads was insulated? The idea is to reduce the heat radiated from the block & maybe the heads too, and then also put the reflective material on the bottom of the manifold to block what’s left.

Could this potentially cause other parts of the engine (the heads, I’m thinking) to become hotter than otherwise? I’m also wondering whether it could become so hot as to damage something. There is about a 5cm gap between the manifold and the top of the block & heads.

And lastly - does anyone believe it may not even be worth the trouble? We can see a drop in temps based on Justincredible’s thread, however the manifold is specially made of a magnesium alloy which has really good thermal conductivity properties (eg. it heats up and cools down very quickly) - and he would have had to have been stationary for some short time before taking the temps (justincredible, can you confirm how long from stationary to temp reading?) Is it possible that the manifold drops down to the same running temp in both cases, after a few mins of intake air passing through it (inductive heating)?

Obviously the answer is testing, but I’m hoping we could narrow it down before I spend more time on it than I have available :slight_smile:

Cheers!
-P

#2

Paul

The spacers stop the transfer of the cylinder head heat into the intake manifold. The intake being higher isn’t going to hurt as now there is more room for air to flow under the intake to help keep that cool as well. The reflective tape is just that it’s meant to help reflect some of the raident heat.

When I did the tests they were all on the same stretch of road at the at the same speeds. When you drove to longer distances the heat would go up more and more the spacers did better and better as the motor Temps went up. The measurement was done very quickly by pulling over onto the side of the road to jump out to grab a reading. The test was done 4 times in a row to assure consistent results. They were all very consistent. The only non consistent result was with the stock car. The Temps only got worse each time as the car got more and more heat soaked. We took the average temperature from those runs.

I think JHM makes spacers for the v10 you should ask.

#3

Thanks very much, mate

I just sent JHM an email - I don’t think they make them for the V10, but I’ve asked what material they used for yours, and if they’d be interested to develop them for the V10 if I can do some of the legwork.

It seems pretty cut-and-dried that lower manifold temps can only be of benefit, so the spacers are a worthwhile mod.

#4

Spacers have been a good mod for several motors that suffer from extreme intake heat. I would think the difference is going to be even bigger with your car.

#5

JHM emailed me back to say they have done a few spacers for the V10, and they’re going to see about getting me a set for test fitting!

Hopefully I will hear back soon. Will keep you posted.

#6

Nice!!!

#7

very nice im interested.

#8

me too.

#9

That’s great. Now I just need JHM to reply to my emails.

They did quickly at first, and said they’re going through some sort of reconstruction, and weren’t sure if they could get to the area where the V10 spacers were kept.

Now no reply to my last two emails, and the new manifold is here. Not sure if I can wait.

Anyone have any contacts at JHM? They wouldn’t give me any direct contact details for the V8 tech ‘mystery man.’

P

#10

Let me know if you get the spacers im interested

#11

I have been following some of these performance related threads very carefully. I am planning on purchasing a s6 soon. As far as cooling intake temps how about water/ methanol injection? Actually it would cure another serious concern with the carbon build up too! as a bonus the cooler charge would give some good hp gains as well. I have read a lot over then last few days about performance options but the only mention of water/meth was from a couple years ago and the thread got turned into a bunch of guys getting mad because the poster said he usually cruised about 100-120mph to work everyday. I have seen people say it water/ meth injection does not remove old carbon just prevents build up which in it self would be more than enough reason to do it, but I have personal seen a difference in elimination of carbon build up b4 and after, but that was on a supercharged engine maybe the that had a factor but I can’t see why it would make a difference. Regardless when I get my s6 it is one of the first things I plan on doing. If there happens to be a kit already in existence i’d love to get the link.

#12

lol I just realized this was for the exhaust manifold…

#13

Hi mate, I can’t speak to the water/meth injection, though your logic seems solid.

This is indeed for the intake manifold, not exhaust!

Still waiting on JHM.

-P

#14

lol, I had it right the first time then ha! Well from what I have seen there seems to be more and more interest some after market for this v10 monster. The water/meth is great for heat reduction so I would strongly suggest looking into it. I have seen mock ups for intercooled systems vs water meth injection only, and you would be surprised how well they compete, and like I said even if it just prevents the carbon build up it would be perfect for this system.