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bass gt · Posted: Tue Aug 07, 2007 7:45 am Post subject: Intercooler Efficiency Update

Guy's,

Managed to get to a track day today with the aim of getting some meaningful data from the car.
After a few runs i pulled the data logs and looked at the intercooler pre and post temps.
Now today was a lovely day, about 25 degrees C in old money.
So how does it work??
Well, the logs show intake temps before the IC of 90 Degrees. Now I'm not sure if the ECU data units are in deg C or fahrenheit, but the post IC temps were around the 36-39 deg area.
So all in all, it seems i am taking a major chunk of temp out of the charge air.
One note is that the temp sensors are of the standard Bosch type, not K probes, so they are not so quick to update, but i ran for over 15 minutes, with the log resoulution set to 0.1 sec, so there are reams of data!!
But by the seat of the pants, it felt very good. Quite a few people were slightly amazed at it's performance. One indicator was i pegged a Ferrari 355 spyder along the 1km straight, and he neither lost me, nor did i gain on him. And i know he had it pinned open!! However, i was in 5th by the end, and he was probably in 3rd!!
So, i think the upshot is that the bonnet vented IC is a major success. One last thing to do is increase the size and profile of the deflector, and i think it's good to go.

Regards,

Steve
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Front Wheel Drive is the Devil's work.

endwrench · Joined: 07 Dec 2002 Posts: 1631 Location: Victor, Montana

Great info Steve! Think I'll do a little "before and after" IC temp testing of my own. I can't datalog the before but I can measure it.

You basically have a rise of only 20°F over ambiant. That seems pretty phenominal! I forget, how much boost are you running?

Todd
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'79 924NA. Rebuilt 9.5:1, MSDS header, Mega Squirt Injection, MJLJ-EDIS Ignition, 1.6L Whipple Charger and Intercooler, 10lbs Boost, 944 Trans, Custom HD Clutch.
"simsport" said....superchargers are better than turbos its official!....

bass gt · Posted: Tue Aug 07, 2007 5:01 pm Post subject:

Todd,

The car was running at 15.2 psi of boost. As this was a track day, the car was pretty much flat out all the time!! It seems that my Garrett/KKKhybrid turbo is running very cool. I think this indicates the turbo is way too big for these engines.

steve
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Front Wheel Drive is the Devil's work.

Raceboy · Joined: 01 Mar 2004 Posts: 2327 Location: Estonia, Europe

leadfoot · Posted: Tue Aug 07, 2007 9:48 pm Post subject:

Scary to think what they ran to get 375hp...
close to 30psi ??
Leadfoot
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1981 ROW 924 Turbo -
carbon fiber GT mish mash
LS1 conversion in progress...

Paul · Posted: Wed Aug 08, 2007 10:16 am Post subject:

21.75 PSI bored/stroked to 2.4 litre yeilded 450 hp for a 2050 lb car. Notice the cam driven water pump and the backward firing injectors.

http://im1.shutterfly.com/procserv/47b7d923b3127cce8627565caa3500000026108AZuGrlozZtE

http://im1.shutterfly.com/procserv/47b7d923b3127cce862750d1aabb00000026108AZuGrlozZtE

http://im1.shutterfly.com/procserv/47b7d923b3127cce86208ca0ca7100000026108AZuGrlozZtE

http://im1.shutterfly.com/procserv/47b7d923b3127cce86208dab0bd200000026108AZuGrlozZtE
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White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

Lizard · Posted: Wed Aug 08, 2007 11:57 am Post subject:

bass gt, what was the ambient temp when these readings were taken.
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3 928s,

!tom · Posted: Wed Aug 08, 2007 2:07 pm Post subject: Re: Intercooler Efficiency Update

bass gt · Posted: Thu Aug 09, 2007 12:13 am Post subject:

Well, I've been back through the figures, and all seems correct. There was a rise in pre IC temps as the session went on, which is mirrored in a corresponding rise in the post temps. I guess this is IC heat soak. Now the logs show i was on or over 80% throttle for 70% of the time. So i guess the IC had little time to cool down in a non boost state.
Now by my rough calcs, my IC is operating somewhere in the region of 75% efficiency. Not bad. Now i think there is a bit of fine tuning to do, to imptove the airflow over the vent, and maybe look at a fine water misting device to give the IC a shot of the cold stuff, just to help of course!!

Steve
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Front Wheel Drive is the Devil's work.

Fast924S · Joined: 18 Feb 2005 Posts: 39 Location: New Haven, CT

Just try this

http://www.machv.com/ntercooler.html
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Rebuild COMPLETED, Many mods, better power, Just ask for info