IC airflow Q

[Alan L]

My beast is only used for track time. I have just fitted a 964 IC. I bought the 964 airguide plate/shroud too - but can't seem to get that to fit. So am going to build some sort of shroud to feed air into the IC. One experienced P tuner did tell me to block off all air to the engine except via the IC. Has anyone gone down this track - is it a tried/tested method? Obviously engine temps would be the concern. At the moment - with previous stock IC configuration engine temp never went beyond 9'oclock - which is very comforting.
Thanks
Alan

[RarlyL8]

I've done that and found (logically) that you can get away with it if the intercooler is big enough. Full bay is big enough, half bay is not.
The air drawn through the IC when the lid is blocked off is phenomenal. Make sure the firewall insulation is in place and the engine tin is good as air will be sucked in from every hole.

[Alan L]

Thanks Brian. So I take it the 964 IC is not big enough for this? Meaning I should not block the rest off? As much air thru the IC as possible is obviously the point. Maybe a compromise would work with a 1/2-3/4 bay IC? Maybe I could block some of the other vent space off, to increase flow thru the IC?
Regards
Alan

[RarlyL8]

You'll probably need to monitor cylinder head temperature to find the threshold where restriction deminishes to the point where the engine temps are not affected.
This is what I did. Started with a 1/2 bay IC and opened the block-off plate progressively until no change could be detected in engine temps. In the winter I could leave the plate in with only the GT2 ducts open, one of which fed the air cleaner. This was a street car so very different requirements.

[Alan L]

What was the purpose on a street car Brian?
Or are you just a hardcore petrol head at heart :-). (I probably know the answer).
Regards
Alan

[RarlyL8]

The difference was nothing short of remarkable.
Heat soak nearly disappeared and power increased all around on boost. It made a believer out of me that proper shrouding and air ducting is critical. Air takes the least path of resistance, and going through the intercooler instead of around it apparently is quite a resistance!

[Strygaldwir]

My stock 79 configuration had no condenser for the Air Conditioner and had the extra space blocked off. These appear to be all stock parts and part of the normal configuration.

[Alan L]

Originally Posted by RarlyL8

The difference was nothing short of remarkable.
Heat soak nearly disappeared and power increased all around on boost. It made a believer out of me that proper shrouding and air ducting is critical. Air takes the least path of resistance, and going through the intercooler instead of around it apparently is quite a resistance!

That must be why the tuner guy suggested it.
Thanks
Alan

[baloo]

Originally Posted by RarlyL8

...
...Started with a 1/2 bay IC and opened the block-off plate progressively until no change could be detected in engine temps. In the winter I could leave the plate in with only the GT2 ducts open, one of which fed the air cleaner.

Brian,
1) How did you progressively open the plate? Was this on a slide, or did you cut different size block off plates and put them in place?
It looks like the entire non-IC part of the tail screen is completely covered up.

2) What or where are the GT2 ducts to which you refer (basic ignorance on what the GT2 looks like)? Are these scoops on the sides of the tail?

Thanks.

[Tippy]

I have a full bay IC and it's not shrouded at all. Huge gaps between opening of wing and no problems with hot IC temps.

On 100*+ days in south Texas, only about a 10-15* delta over ambient at 1.2-1.4 bar.

[RarlyL8]

Shroud it and see what happens.

Yes I made several aluminum plates with progressively bigger holes. Also blocked off the GT2 ducts first then opened them back up.

[Miguel Antonett]

^^^+1 Try it!

[Tippy]

I guess it'd make more power, but at the expense of engine temps. Hmmm

[Alan L]

I suspect, as Brian suggests, there is a point where it is win/win. Assuming the fan is moving surplus air - ie some wasted air (where if the fan flow increased you wouldn't see any real change), what you are directing is the 'surplus' capacity into the IC. From what Brian says, there are clear gains to do this. As long as you don't go beyond the point where the engine becomes starved. Of course the IC air ends up in the engine cooling anyway, and hopefully the IC temps have dropped, which means cooler engine and cooler air for engine.
I am building my shrouds currently.
Alan

[puddy]

Hmmm this sounds like another project for my car! Thanks!

[T77911S]

i figured the big air gaps around my RUF IC was lost HP. after all, why put a bigger IC on just to let air bypass it.

so i got some flat metal and along the edge i bent it over 180 derees. then i got another piece and did the same thing. then i cut the piece off and tack wleded it the first piece to make a chanel for a rubber seal to slide in. kind of crude and maybe a bit redneck, i am in the south, but you cant really see the chanel anyway.
i had an old engine bay seal that i used to slide in the chanel. then i attached it to the deck lid. now the IC is sealed.

the seal kind of looks like the factory 930 seal the way the rubber sticks down.

[Pat RUFBTR]

Originally Posted by T77911S

i figured the big air gaps around my RUF IC was lost HP. after all, why put a bigger IC on just to let air bypass it.

so i got some flat metal and along the edge i bent it over 180 derees. then i got another piece and did the same thing. then i cut the piece off and tack wleded it the first piece to make a chanel for a rubber seal to slide in. kind of crude and maybe a bit redneck, i am in the south, but you cant really see the chanel anyway.
i had an old engine bay seal that i used to slide in the chanel. then i attached it to the deck lid. now the IC is sealed.

the seal kind of looks like the factory 930 seal the way the rubber sticks down.

This is why I modified my IC Ruf, then I surrounded him(it) with a plate(patch) in carbon as well as with an air inlet for the box with air.

[Miguel Antonett]

Originally Posted by T77911S

i figured the big air gaps around my RUF IC was lost HP. after all, why put a bigger IC on just to let air bypass it.

so i got some flat metal and along the edge i bent it over 180 derees. then i got another piece and did the same thing. then i cut the piece off and tack wleded it the first piece to make a chanel for a rubber seal to slide in. kind of crude and maybe a bit redneck, i am in the south, but you cant really see the chanel anyway.
i had an old engine bay seal that i used to slide in the chanel. then i attached it to the deck lid. now the IC is sealed.

the seal kind of looks like the factory 930 seal the way the rubber sticks down.

A picture's worth x000 words... come on!