How important is a seal on the intercooler?

[EA930]

Talking about the seal between the vents on the bortom of the rear lid and the top of the inter cooler. I realize the cooler the air the better, but has anyone got any sort of quantative data?

Car came with Kokeln sans any seal and I'm just trying to figure out if it's worth trying to fit something to it.

[Tt surgeon]

Probably minimal gains.

[RarlyL8]

Air does not like to go through an intercooler unless it is forced to, either by a shroud or pulled through by the fan. How much you are loosing depends on the size of the gap. Worst case is your IC becomes a heat sink. If you still have the OEM shroud in place and only the gaskets are missing then at least air is pointed in the right direction. Air pulled by the fan will still go around.

[wjfk32]

Greetings:

Every little thing regarding airflow & aerodynamics is substantial to get the most out of an engine/car.

I think JBL was doing some testing on his turbo--top end runs.. He believed his intercooler was not sealed to the lid enough and holding him back.

I just do the old fashioned way...After a long run..I just open the hood and put my hand on top of the intercooler...Feels good when its nice and cold.

Walt

[Rodsrsr]

Plus one on what Walt says. If the intercoolers cold, its working....

[mark houghton]

Originally Posted by Rodsrsr

Plus one on what Walt says. If the intercoolers cold, its working....

Cold....as in, no warmer to the touch than outside ambient air temperature? This aint a swamp cooler doing evaporative cooling, so technically it couldn't be any colder than the air that's being drawn across it.

So if it isn't cooler, then it's either because the ambient air temp is at least as high as the charge air temperature after going through the turbo compressor (unlikely unless you're driving through the Mojave), or there isn't enough air movement down through the IC (per the original posted question).

I'm guilty of never fitting on a seal to my B&B IC, 'cause it fits within maybe 3/8" of the shroud so I figured good enough. Someday I'll have to fab on some sort of flexible rubber seal (unfortunately it would probably have to be glued on since there are no other provisions for attaching a seal).

[mark houghton]

Originally Posted by wjfk32

I just do the old fashioned way...After a long run..I just open the hood and put my hand on top of the intercooler...Feels good when its nice and cold. Walt

Come on Walt, the real reason you do that is just to show off how "cool" you are Besides, onlookers (gawker-wannabee-often crackhead-kids) just love to see what's back in the trunk of these air-cooled classics. Not too long ago when I pulled into the local autoparts store, the young kid behind the counter almost creamed his jeans. "Is that a 911 Turbo"? I said - "No, it's a 930" (now go back and read the thread on that topic for kicks). He comes out....drools on the tea tray..."can I see the engine"? "But of course" - says I - "but watch that intercooler, it may be hot".

Then he asks his friend "do you think it would beat your Honda Accord"? I snickered and left.

[wjfk32]

Mark you are to funny. Happy New Year

I get my GF- (A little intercooler 101)--to put her hand on the intercooler..At first she thought i was going to chop her hand off..
I am happy when the intercooler feels ICE-COLD to touch...IZT WERKING YA..
Now- She can't get enough of boost-torque..blah-blah...

I only jumped out a few times to open the lid--but not for the intercooler but the SMELL OF GAS--HOLY MOLY)..No fun seeing your gas line and mist flowing ever so nicely in the sunlight....Always cary a fire extinguisher.

[bleachii]

Does this apply to stock IC and engine as well? It would be cold to the touch?

[wjfk32]

I'm stock/IC and the colder the weather is EVERYTHING..After doing some nice--top end runs- and a little cool down--chking the intercooler/touch-car running--ICE Cold 30+ degree weather-

Mind you my car only has 20,000miles on the rebuild/engine in 1994--SC Cams-polished heads-Hks Aic-open KN Filter-No AC-Front oil ,cooler-MSD6AL-7006.blah-blah.Don't know with all this stuff, makes it flow better?? maybe a little..I just know my car just loves top end..At 55mph-60mph in 5th gear-915..Its smooth but not..edgy--Does not feel comfy but lazy..just a boring feel.

[RarlyL8]

Yes the IC should always be cool (read lest than 98.6°F) to the touch while the engine is running.

[Rodsrsr]

Originally Posted by mark houghton

Cold....as in, no warmer to the touch than outside ambient air temperature? This aint a swamp cooler doing evaporative cooling, so technically it couldn't be any colder than the air that's being drawn across it.

So if it isn't cooler, then it's either because the ambient air temp is at least as high as the charge air temperature after going through the turbo compressor (unlikely unless you're driving through the Mojave), or there isn't enough air movement down through the IC (per the original posted question).

I'm guilty of never fitting on a seal to my B&B IC, 'cause it fits within maybe 3/8" of the shroud so I figured good enough. Someday I'll have to fab on some sort of flexible rubber seal (unfortunately it would probably have to be glued on since there are no other provisions for attaching a seal).

All I know is that every time I open the lid after extended spirited driving, the first thing I do is touch the intercooler and it's cold. I think that sometimes we have a tendency to get too technical and too theoretical which doesn't always comport with practical reality. There are too many variable's to make absolutes here. For a race car on the threshold of boost limits, sealing may be absolutely necessary, while unsealed may work fine for normal street driving. Thats my take and I'm not sealing mine until I have a need to do so.

[mark houghton]

Originally Posted by Rodsrsr

All I know is that every time I open the lid after extended spirited driving, the first thing I do is touch the intercooler and it's cold. I think that sometimes we have a tendency to get too technical and too theoretical which doesn't always comport with practical reality. There are too many variable's to make absolutes here. For a race car on the threshold of boost limits, sealing may be absolutely necessary, while unsealed may work fine for normal street driving. Thats my take and I'm not sealing mine until I have a need to do so.

Well said, and thanks for the dose of reality. I doubt I'll ever seal mine either.
But I still love dwelling the the technical and theoretical, challenging conventional wisdom.

[Ronnie's.930]

I think many of you are undervaluing sealing the intercooler opening to the tail - I think it does a great deal . . . I have never measured temps with and without the shrouding on a 930 intercooler, but I have done so on a 2001 Ducati 748r endurance racer. In the Texas summer heat, the water temp dropped about 15 degrees by adding simple, plastic shrouding (about a 1" protrusion from the front of the radiator) to the sides and top of the radiator - this was a much bigger change than I anticipated - interesting how this might pertain the intercooler. . .

This was my solution for shrouding a Garretson:

Intercooler Shroud - Home Brew !!

[RarlyL8]

You're leaving a LOT of power on the table by not shrouding your IC. Why pay for it and not fully utilize?
If you want to retain the neckid looks when the lid is popped then add the shroud to the lid and not the IC. The red rocket has a GT2 tail which is very open. I made a shroud in the tail and just that small area above the IC that is forced to go through instead of around makes a noticeable difference, both in performance and delaying heat soak.

[vas930]

Why dont they make the darn things with a lip or something for easy attachment?

[SCHNELE]

Shrouds smouds, water meth injection and the debate is over.

[EA930]

Originally Posted by RarlyL8

You're leaving a LOT of power on the table by not shrouding your IC. Why pay for it and not fully utilize?

That was the original concern- as with anything else, it is a matter of balancing the tradeoffs. For day to day use, if it's not a large amount of power I'd rather leave a little power on the floor and keep the air flowing over the engine keeping overall temps down.

Bottom line it looks like we're going to need to dyno with and without to get some data.

[RarlyL8]

Unfortunately dyno data will tell you absolutely nothing. The car is not traveling down the road and the air around the IC isn't even moving on a dyno.

All of the engine compartment air should not go through your intercooler unless the intercooler is a full bay unit. That would be a restriction of air to the engine cooling fan. I blocked off flow to all but the IC on my GT2 wing in the wintertime and saw substantial changes in performance and engine temps. My engine ran so cold in the winter with the wide-open grill that the WUR would kick into warm-up pressure mode and the idle would oscillate at a red light. In the summer the opposite happened and engine temps rose, so I revised the shroud to allow just the space over the IC to funnel through it and the fan to pull unrestricted air from the open areas. This turned out to be the best compromise and the IC stayed cool to the touch. With no shroud the IC was a hot heat sink with noticeable lag and down on power.
Shrouding costs little more than your time and has great benefit for a street car. I designed my stock replacement IC to butt up against the OEM shroud for full use of this free HP. Give it a try and you'll never ask the question again.

[wjfk32]

I think I will get a very thin plexiglass across the lid and make some nice clean attachments. I've seen this done in the 80's on turbos.

ALL That beautiful cutting-angles-shroud-is the right way...But I DON'T have superiour skills or machinery to take it to that level.


Walt