I S4 I - Hilton

Recently i have noticed quite high intake temps with vag-com, even with normal driving... and extreme intake temps during spirited driving...

50 deg C normal intake temp
70-80 deg C spirited intake temp

Ok.... now all repeat after me "HEAT SOAK"

Now i have a thermo couple multimeter i used while doing this testing. I monitored different parts of the engine bay and intake tract surfaces... verrrrrrrrry interesting!!!!

I wont bore you with all the figures... suffice to say a lot of heat buildup is post intercooler.... intake manifold gets very hot!! (75-85deg)
The entire intake tract (including the airbox) gets quite hot too.. (from 50 to 70 in various places)

So i figured i can make the factory intercoolers much more efficient just by eliminating pre/post intercooler heat buildup..

How? With high temp ceramic coatings on the intake manifold (inside and out) plus a ceramic intake manifold gasket. Will probably get the intake flowed and ported while its off, before it gets coated.

External ceramic coatings on the rest of the intake tract including airbox, to keep the nasty power robbing heat out!!!

Im also toying with the idea of internally ceramic coated dump pipes to help get the heat away from the turbos and keep the hot gases flowing.

To further improve things ive thought about water sprayer for intercoolers or maybe 2nd hand water/air intercooler replacements.

Why go to all this trouble??
This should get me on or below ambient temp even while still running a good dose of boost!
I can run slightly more boost and more timing, while also gaining more power from the lower intake temp.

Ive read somewhere that you lose 1 HP for every couple of degrees on your intake. In a chipped S4, thats a significant power loss from heat soak!!

So over to you guys for comments!!
H.

squidix9

You're right

SMOKINA4TURBO

You thaught about getting a better IC core or improve the IC?

Your idea's are good and ceramic coating is always a +. I got some parts coated...more for the exhaust to keep the velocity up. Does work good on the IC parts too, just kinda pricey. Its cheaper if you do it all at once.

Go do it and report back what u found out in your testing.:-)

BTW 1 degree of timing is a lot more power then 1 hp.

Lambo-Bully

You could try directing air flow from the driver's side flap(mirrored where the ram air intake is) through the underside of the intake manifold, should be worth a few degrees....

Ceramic coating is more for exhaust, to reduce the heat that gets out, not to shield it from getting in. You could get your intake manifold done by extrudehone.com, for the right $. Try making a better heat shield for your airbox, like this:
<img SRC="http://pictureposter.audiworld.com/21967/p2100002.jpg">

AWE is also coming out with water to air IC replacements, might be worth waiting for. That should be able to drop temps below what you're shooting for...<ul><li><a href="http://www.awe-tuning.com/pages/shared/part_detail.cfm?PMaI=1&amp;PMoI=4&amp;PEI=6&amp;PP =s4_27t_drivetrain.cfm&amp;PPT=Drivetrain&amp;IL=s 4%20intercoolers">AWE Intercoolers</a></li></ul>

RangeR BoB

1) Nice idea about ceramic coating the exhaust, keep the heat in until the cat. Do the whole exhaust manifold and turbo hot section.

2) the turbo compressing air is where the heat comes from. Ceramic coating the intake tract won't help that. You don't care about metal temps, you care about air temps.

3) Unless you use refrigerant, you will NEVER get intercooled air below ambient. it goes from 25C outsde to 300C post turbo to 100C post intercooler. That is still warm.

4) a bigger intercooler will help, as will a more efficient turbo.

5) water sprayers work, but at a premium. How about water injection like Aquamist instead? A4s have large washer reservoirs.

Good to see some original ideas! Keep it up! I agree that you should do your mods (preferably one at a time) and then measure the effects to see what you get.

xr4tic

although on an S4, the plumbing starts to get a little complicated.

Ideally, you'll have a small water injector in front of each IC, to help prevent heat soak, then one large injector in front of the TB.

If setup properly, it will be more effective than a larger IC, and you won't have to worry about pressure drop.

Running just one injector in front of the TB on my A4, I've seen intake temps drop from 150F at WOT to 110F. Because of the lower intake temps, the timing went from ~12 degrees to 18 degrees.

Lower Temps =&gt; Less/No Detonation =&gt; More Advanced Timing =&gt; More HP

Water injection only works under boost, but that could be good for fuel mileage, as you should use less fuel at part throttle with warmer intake air.

TTschwing

<center><img src="http://images2.fotki.com/v10/photos/7/7305/137712/postheat-vi.jpg"></center><p>Here's what it took to get these results....

Force fed, positive pressure airbox
Samco hoses
FMIC
Manifold insulators

I've got an IC mister set-up too, but not activated during this test. I've also got digital temp readouts on my airbox, IC in, IC out, Ambient, and (with a VAG) Manifold so these numbers are real. Heat is a killer but can be effectively eliminated step by step. The manifold insulators alone lowered the manifold temps 20% and resulted in a significant timing (read more performance) bump. I've got lots of these ideas and install pics at my Fotki link below!

Steve

I S4 I - Hilton

I will definetly have to pursue the ceramic coatings and manifold spacer!

You have made some excellent mods and done some great research!