Dknebes

Stephen,
I still find it hard to believe that you will feel the difference. If he can get a deal on the Garretson why not go that way. My feeling is both of them are to small and if you ever want to go with more mods you will have to go bigger anyway. I would spend the money and go with a big intercooler right away. I know not everyone wants 700hp so that may not be practical. My biggest problem has always been not planning ahead and it has cost me thousands.

David

SGOGT4

The Garrettson is actually already on the car.

jetskied

Dollar for dollar invest your money in headers, or K27HF before changing the IC. As said before the IC does not make HP. First you have to get to 500HP before a better IC will get you more HP. The Garretson is a good IC for most milder modification.

Sameer

Gents,

I've posted this many times and will do so again as it is related to this thread.

The Kokeln Intercooler is the finest, most efficient intercooler on the market BAR NONE! Kokeln Intercoolers produce lower intake temperatures and higher flow than any other intercooler due to a larger cooling mass, superior design and greater efficiency while retaining the factory air-conditioning! Comparison of the Kokeln Intercooler to other products on the market revealed the following:

Test Result

Charged side face area in square inches Cubic inch mass
Stock 21.4 258
Andial (Garretson) 72.6 508
Ruf 53.5 498
Kokeln 73.0 642

For comparison purposes a test was ran on a stock 1988 911 turbo at 5000 rpm with an outside ambient air temperature of 85 degrees Fahrenheit and turbo flow rate was approximately 430 cfm. The results were as follows:

Intake Temp Outlet Temp Pressure Drop
Stock 218 151 .50
Andial 220 120 .50
Ruf 220 119 .50
Kokeln 222 109 .48

Fits in the stock location, with Air conditioning, can flow as much as 900 CFM @ 2.6/1 pr Ratio with less than 1 psi drop

For all '78-'89 930's
Turbocharger and Intercooler technology have improved dramatically in the past few years. The Kokeln Intercooler uses the latest technology in every aspect from the core material to the bypass valve assembly. The bypass valve included in he installation kit replaces the old cast aluminum valve (7 Pounds) with the latest bypass technology. This valve (less then 1 pound) bypasses more air faster than stock and provides boost approximately 1000 rpm sooner.

Kit includes: Intercooler, bypass valve, bypass sleeve, rubber elbow and all mounting hardware and fittings.

Dknebes

I would like to see a dyno comparison with rear wheel hp. I agree that the Kokeln flows more and all of the rest but the Garretson was already on the car and he wanted to know the difference. I do not think you would feel the difference if you switched the two intercoolers on basically a stock engine I’m talking about the Garretson and the Kokeln. I have gone from a large custom intercooler to a real large custom intercooler that flows more but I also went to a larger turbo and some other upgrades. I already had pushed the smaller intercooler to its limit at 693hp it could not flow anymore. The new intercooler will flow up to 950 hp if you had an engine that could produce that much boost and heads that could flow that well. I have a 3.3 that is now a 3.4, and was told there is a limit to the 3.2 heads and that they do not flow as well as the 3.6 heads which can produce more flow and more hp. I am sorry that I got off the track here I just started to ramble.

David

JBrown

i have a gerretson intercooler on my motor it is stroked to a 3.5. the motor is based off a 3.0 intake system. does kokeln make a intercooler for my application. I am running modest boost does it pay to go with the kokeln? thanks john

SGOGT4

Sameer - No offense as I enjoy reading your correspondences via rennlist but why do you insist on simply copying in the verbiage off of the Kokeln / Lindsey website? Most, if not all of us, have seen it and I have seen you post it numerous times while searching the archives. The data is good and if you have personal experiences, data acquisition results, even just opinions great but lets leave the marketing to the guys trying to sell these things.

Sameer

Rob,

I've not done any dyno comparisons with the Kokeln versus other aftermarket intercoolers as the Kokjeln is my first and I'm happy with it so far, this is the only comparison I've got, off their website. I'd be happy to see if others have done dyno runs and made comparisons. JMHI.

Geoffrey

The two aspects of intercooler design that we're talking about here are efficiency of cooling, and pressure drop. The degree of effectiveness of any intercooler is how well it cools the intake charge temp which increases density, and how much pressure is lost due to the restriction in the intake tract that the intercooler creates. For instance, if you have an intercooler that takes 250F air from the compressor outlet and cools it to 90F with a 1.5psi pressure drop, there probably isn't any advantage of going to larger intercooler as the larger cooler will increase the pressure drop since it is a larger restriction. There are two different designs available - bar and plate, and tube and fin, and two different strategies of aligning the cores, front/back and side/side.

From my experience, the stock intercooler has been designed to cool the volume of air at .7bar of boost and will cool adequately. If you increase the boost pressure, or increase air flow (3.4, 3.5l, k27 or Garrett turbo), it will not be adequate. The Garretson is an old intercooler design and the Kokeln utilizes newer technology and incorporates a better bypass circuit that the 930 CBV.

On a mildly modded 930, I dont' know how much a difference you'd see between the 4-5 intercooler choices out there (Garretson, Kokeln, C2 Turbo, Ruf). As David pointed out, 450hp+ requires a custom built full bay intercooler for adequate cooling.

ToyCollector

Good thread. Currently freshening up a 3.4L (Andial full conversion from the late 80s) 88 930 with the Andial/Garrettson Intercooler, twin plug heads, K27, cams, etc. Due to planned changes doing research on getting the Kokeln as we open up the induction. If I go that route, I will let you know my thoughts during and after. Having seen the specs on Kokeln's site, that old Garrettson is no dog by any means. Would love to see some postings on the C2 Turbo IC setup as well.