docmirror

This is what I was trying(poorly) to say when I was discussing the temp Q vs the pressure drop. It's a matter of optimizing the two opposing elements. Which is why I didn't like the spec for the IC from the OP. It gave the pressure drop, but not the temp Q at any flow rate or pressure.

Cosmo Kramer

So basically in a nutshell an intercooler that cools the incoming air better is generally more restrictive then one that flows better?

dprantl

If you're using an evaporator, then why not hook it up to the A/C compressor instead

Dan
'91 928GT S/C 475hp/460lb.ft

Cosmo Kramer

I always wondered if that would work, could this somehow be tied into an existing working A/C system? That would really do the trick LOL!

dprantl

In terms of plumbing, it would be no different than a rear A/C setup. I was working on such a system when I was thinking of adding turbos to my '86. That stopped when I bought my GT and sold the '86. I already completed a dual parallel-flow A/C condenser that fit in the stock location with the stock receiver-drier attached and was about to start on the evaporator that would fit where the airbox was.

Dan
'91 928GT S/C 475hp/460lb.ft

Fabio421

Originally Posted by Cosmo Kramer

Ford did that in their Lightning S/C'd trucks. It was only good for a few seconds if I remember correctly.

dr bob

net performance, at least in a steady-state system, is tied to how much total heat you can reject. That includes heat from the engine, AC system, trans coolers if you have them up front, and now add in the IC heat load. Most installs just stack the exchangers in the same airflow, so the pieces at the cooler end of the stack just share their rejected heat to all the elements stacked behind.

So where do you mount the discharge heat exchanger in one of these A/W IC systems? Duct from the slab face of the bumper to exchangers under the headlights in the front of the wheewell, vented into the outer edge that wheelwell? Don't really want to add heat to the brakes either, so separate ducts for brake cooling too?

Many moons ago on my little turbo Saab project, I used an air/air IC setup mounted low in front of the radiator, with inlet air from below the bumper. Air exhaust from the IC went to the wheelwell. Basic thermo characteristics for the A/A were better than any A/W setup I could fit. Stoplight to stoplight there wasn't enough mass in the unit to match an A/W, but after fifteen seconds of hard boost the A/A pulled ahead in all the simulations. My performance requirements included extended (relatively) high-speed operation under boost; stoplight performance wasn't a big concern.

Ketchmi

Yeah, 0 thermal reserve on the A/C assisted intake cooler. The capacity is not nearly enough for an extended pull but would be great for a couple of seconds.

Restriction is another variable that needs to be taken into account depending on your intercooler design. If the air just blasts through the core without staying long enough to get cooled, it is not efficient at all. A thin core can use a higher fin count or fluted fins to slow down the air enough to get sufficient cooling in a short distance. A long core, like the one that started this discussion gives plenty of distance for the air to be cooled, in fact too much in my opinion.

Imo000

I've heard about the AC intercoolers too. I think Mitsubishi or one of the other Japaneese manufacturers did this too. I can't remember the details but I know I heard from this a long time ago.

slate blue

As Richard said the Laminova heat exchanger is the best, many manufacturers are currently using their product as OEM fitment. It is a completely unique patented design. It has the lowest pressure drops and Hacker I think the IC in the Mac was just upgraded in terms of size and it is Laminova too I believe. It would make sense since they use the most efficient supercharger the Lysholm which is part of that Swedish group.

There was a fellow on Ebay just selling the Laminova cores in MI. They are used in the supercharged Cadillac Depending on your application you then have to building the housing. I bought a number of them because they were cheap and very light, 500 grams or so. You can use them as oil coolers etc, so multiple use. Laminova can be used with your air cond, they will help you with the technical details if you go down that route.

Greg

Ketchmi

I was considering these for a short while but I couldn't get answers to some of my questions.

http://www.pwr-performance.com/intercooler.htm

blau928

Greg,

I don't think many of the respondents here understand how the Laminova cores work, and actually sat down to do the math to figure out how much surface area each core has, and is able to operate with Laminar flow, low pressure drop, and why the units work so well.

A 332mmX39.5mm core is able to support 150 HP worth of airflow at 90%+ efficiency with lesss than 1 psi pressure drop across the core with a coolant flow rate of 40 Liters/min and using the inner coolant passage restrictor. The 392mmX39.5mm cores do the same efficiency, but can handle 200 HP worth of airflow instead of 150 HP like the 332mm unit at the specified flow rate....

In addition, the flow is Laminar, whereas in any bar and plate, or other type of intercooler, you will not have laminar flow on the cooled charge.... Air:Air coolers seem to work better over time, due to the limit on the cooling medium in the intercooler system based on how it is made. To run long distances, you need more coolant for greater thermal storage capacity, and heat rejection. That means more than 5 gallons, and the washer bottle on a 928 does not hold 5 gallons of water unless you add some anti matter to it. So, you need to make a tank, and find somewhere to put it. On a 928, space is limited, so many give up, or say the cooler is bad etc. I did not even get into the plumbing of the coolant lines, as on so many systems, they are plumbed incorrectly.. (Hint, here's free power... The flow should be tank to pump to IC, to radiator, then back to tank...) If not you have made an inter heater, not a cooler...

Further, It is difficult to make one of these coolers unless you have access to a machine shop to cut the end plates, and or all the case pieces, or machinist and a fabricator who knows what they are doing.. However, when done properly, the stuff works the best. Documentation readily available..

Go to the Laminova website, you can readily download the efficiency charts with pressure drop information and do the math... The stuff works really well, if not the OEM's would not have integrated so many of the Laminova units in the modern cars, and Pro Rally teams would not put the coolers on their very expensive race motors.....

On another topic, I am using 6 x 392mm cores for the SC setup I am building for a reason. In addition, I also have a combo engine/transmission Laminova cooler plumbed into the main cooling system with AN fittings to the motor, and fed from the C&R custom radiator I had made..

Have fun guys, either way you go, and which ever cooler you choose, keep those 928's running..!

Cheers,

Ketchmi

I have to agree with Richard about the efficiency of Laminova cores but they are very labor intensive for anything other than a twin screw/roots type setup. I did lay out what it would take to make one for a CS system with my flow and cooling requirements and it was not feasible given the space constraints. They are one of the best designed cores and are a premium setup if you can use them.

hacker-pschorr

Good point - I always forget about those when the topic of IC's is on the table.

I've read quite a bit about them, unfortunately I haven't actually played with them.

Like this?

http://www.cardomain.com/ride/2938213

blau928

Erik,

That setup is not optimized, as the airflow still needs to twist and turn all over the place before getting into the TB, and then a bunch of turns in the manifold, then into the ports. They should have just redesigned a manifold for the LS1 sitting under it.. In addition, if you look at the openings and the surrounds of the cores, it leaves lots on the table, and allows a great deal of the fin area on the core to be unused on the outlet portion..

I had lengthy discussions with laminova engineers about setting up the system correctly, and the extrusions they sell, or you can make yourself is the best way, as it keeps the airflow around the finned core, and increases laminar flow compared to this unit.

This pic uses 3 cores per side.. It is modular in design, and can easily be expanded to 5,6,7 etc cores per bank of cylinders, and bolted to the redesigned intake manifold in the "V" over the intake ports, or a flat of 16 across the top of the motor with the intake runners opening into the "V", and the cooler in a box, kind of like a sandwich over a shortened tunnel ram.... It would not be that big, and take out all of the extra turns etc..

(I'm building one for my boat as well with a BBC in it..)

Just my $0.02..... Don't want to ramble on more...