Intercooler 101

shbop · 12-15-2013, 07:55 AM

Can someone help me understand the basics. Engine, (930/66), came to me with a Powerhaus unit:

I also have another one:

The engine uses the stock diverter valve assembly, which I had to rebuild. It had two springs behind the valve. Got rid of one, cleaned it up, and replaced the end seals. What is the valve located near the lower part of the extra ic? What does it do, and what operates it? Why all the extra ports in this one? I've seen and read threads where the diverter assembly is chopped. Thanks in advance. Would appreciate any help. I should add that I have some additional pieces for the second unit. Look like extension pieces for the larger connection ports. I'll get a pic and post it later today.

shbop · 12-15-2013, 08:54 AM

Here's a better shot of the associated parts of the second IC. Is this what's refereed to as a long neck unit, and what is the function of the HKS valve? What does it replace, if anything. Thanks!

Norm K · 12-15-2013, 09:16 AM

The apparatus on the second I/C is a blow-off valve. Replaces, on a long-neck intercooler, the recirculation valve used in conjunction with the stock (or in your case, Powerhaus) I/C.

Your extra one would probably be of interest to others here, myself included...

JFairman · 12-15-2013, 10:00 AM

The second one looks like a complete and very rare old Garretson long neck intercooler kit for a '76-'77 origonally non intercooled 930. A desirable collector item now.

Someone put the HKS blow off valve on the Garretson inlet pipe.

shbop · 12-15-2013, 07:12 PM

Quote:

Originally Posted by JFairman

The second one looks like a complete and very rare old Garretson long neck intercooler kit for a '76-'77 origonally non intercooled 930. A desirable collector item now.

Someone put the HKS blow off valve on the Garretson inlet pipe.

The HKS "is" mounted to the inlet pipe. Whats it do? Does it replace anything the stock configuration came with? Is it worth trying to use the "Garretson", or should I stick with the Powerhaus unit? Sorry for all the questions, but I'm flying blind over here, and really would like to try and get it right, or at least do the best I can with what I've got. Thanks in advance!

Tippy · 12-15-2013, 07:37 PM

A blow off valve allows the turbo boost to bleed off once the throttle body butterfly is closed shut on decel. Without it, a compressor experiences "surge".

Literally, the air is forced backwards through the compressor of the turbo.

You hear this on Japanese cars a lot. It's that chi-chi-chi sound.

TurboKraft · 12-16-2013, 09:13 AM

Watch videos or Porsche's turbocharged racecars up through the GT1, they make this sound, too, as they dive into turns.

That bare aluminum one is a super rare and extremely efficient Garrettson intercooler package for a 1976-77 911 Turbo. It's a shame someone grafted on that HKS diverter valve. It would have been much cleaner to use a factory 1991-94 Turbo diverter valve and intake elbow.

The PowerHaus-branded intercooler was manufactured by B&B Fabrication and is a standard fit, non-longneck type.

voitureltd · 12:00 PM

Quote:

Originally Posted by JFairman

The second one looks like a complete and very rare old Garretson long neck intercooler kit for a '76-'77 origonally non intercooled 930. A desirable collector item now.

Someone put the HKS blow off valve on the Garretson inlet pipe.

Here one as installed way back then on my 77. It also has a Calloway 7th injector along with other mods to run 1.0 bar on pump 93 or 1.2 bar with 112 leaded, it is indeed a great intercooler. Recently had a guy offer huge money for the car ( 24K miles ) so he could make it stock again.

Told him , no thanks, lots of stock ones out there.

shbop · 12-16-2013, 10:05 AM

Thanks to everyone for the replies. Sure wish I could just drive over, and talk to you guys. The Garretson unit looks like it will only install if I were to remove the factory diverter assembly. Is that correct? What takes its' place?

02fly · 02fly's Garage

I wish you would have got a hold of me, I would have told you what everything was. I f you have any more questions let me know

JFairman · 12-16-2013, 10:23 AM

FWIW, here's a Garretson longneck intercooler I used to have for the intercooled 3.3 liter '78-'89 930's.
This one also has the polished light weight hand fabricated end tanks. All the Garretson half bay long neck and short neck intercoolers I've seen use the same core.

I shined it up with a 4" buffing wheel on a die grinder and put it up for sale here around a year ago for 1000 bucks and it sold in a few hours.
I kept the nice hand made Garretson "beer stein" intake air hose connector like the one in the picture above that came with it to use with a Kokeln intercooler I have now. The aluminum tab welded on the side with two holes in it is for mounting the left side air pump diverter valve mounting bracket if they are being used.

voitureltd · 12-16-2013, 10:26 AM

Quote:

Originally Posted by shbop

Thanks to everyone for the replies. Sure wish I could just drive over, and talk to you guys. The Garretson unit looks like it will only install if I were to remove the factory diverter assembly. Is that correct? What takes its' place?

I believe there are installation issues if installed on a later than 77 930. If you decide to sell I might be interested as mine has acquired some dents over the years.

TurboKraft · 12-16-2013, 10:28 AM

Yes, throttle body angles are different between a 1976-77 3.0L and a 1978-94 Turbo.

If this engine is a 1978- you would need a 1976-77 intake manifold.

JFairman · 12-16-2013, 10:40 AM

Quote:

Originally Posted by shbop

Thanks to everyone for the replies. Sure wish I could just drive over, and talk to you guys. The Garretson unit looks like it will only install if I were to remove the factory diverter assembly. Is that correct? What takes its' place?

This Garretson shortneck intercooler with cast aluminum end tanks for '78-'89 930's was on my car when I got it in 2006.
These pics are from '07 and you can see the origonal magnesium recirculation blow off diverter valve housing under it. It's a quick and easy bolt on.
Now I wish I kept those Porsche spark plug wires. I was stoopid and sold them.

shbop · 12-16-2013, 11:04 AM

Thanks again for all the replies. This is a pic of the 83' motor getting ready to go back to work. It's a 930/66 unit. I think I'll opt to put the Powerhaus back in service. Seems the easiest route for me right now. I've got a steep learning curve to tackle, and you guys have been great.