Fabio421

Please elaborate. Most of us have no idea what you mean. At least I don't.

NickT

ok.. instead of having your normal types of intercoolers.. air to air or air to liquid... Lotus took it one step further and used the output of the AC compressor to cool the air from the turbos. They called that "Charge Cooling" So seeing as some sharks have the rear ac option.. it would be cool if that could be used somehow to create a "charge cooler" type of system.

Just thinking out loud here...

MarkRobinson

i think the pluses would be overshadowed by the minus: running your AC compressor takes a HUGE hit on your power: I feel what I would say is a 25-30hp gain in mine: brand newly rebuilt compressor two (two tried, both felt the same).

So you'd have to pick up another 40hp from this cooling method to really benefit from it (to feel the benefit), and there's also the cost: 40hp is really only 10hp gained since your AC cost you 30, so how much $ did it cost to incorporate this idea for the bottom-line 10hp?

Again, this is theory...BTW: the air/air intercooler works very well.

Gretch

Mark, Very slick install.........it looks like art. My compliments.

MarkRobinson

Thanks. It was a lot of hard work. I wish it could say that this is what the factory *would* have done but I cant. For now, I'm just happy it's there, & makes power, & maintains drivability, & is upgradeable. Good enough for now.

BTW: the exhaust routing to the turbocharger is only about 2' longer than a 944 turbo for those who have asked. 5.0 motor @ 10:1 with a turbocharger sized for a peak 550-600hp vs a 2.5l 8:1 motor with a turbo sized for 300hp peak, shows that the car spools below that of a 951 at a minimum for all you theorists out there.

Darien

BEAUTIFUL MAN

hacker-pschorr

My supercharged 81 lost 15rwhp & 12lbft torque with the AC on. This coming from the original 81 compressor - blows ice cold.

RyanPerrella

OK OK

So Mark, what are you planning on selling this KIT for? I loved the idea of this, i saw this about a year ago as a "squires Turbo" great idea to put the turbo in the rear, takes away the complication of that turbo being underhood and pretty sinple to plumb, that and the fact that there is quite a bit of space under the 928 to run intake tubes inside the frame rails

So whats it going to cost with an initial order of 10 units? $3,000-$5,000?

Fill us in on that detail please

C.F.

Ryan
Have a look at Mark's privious thread for a guide,
https://rennlist.com/forums/928-forum/268537-928-turbosport-information-thread-85-95-cars.html

JG928S4

20 years ago I did a B&E kit on my 924. Biggest problem was the effect of heat on the belts. This was w/out having the criticalness of a TB non clearance like my 928. Maybe I am just a product of "Dark Ages" technology, but what do you do to keep heat form "rising" under those critical belts? My belts would get baked after shutdown as the turbo heat disipated.

Also my experience was/is distance from exhaust out of engine was/is a proportional factor of turbo lag? Am I wrong?

The engineering looks fun, keep going for it!

zoltan944

this question is confusing. I agree with both your statements, but with the turbo mounted near the rear of the car, its not close to the belts and the exhaust couldn't be but a foot or 2 long

JG928S4

Added heat under the car when parked is going to vent where? It will go up the path of least resistance/airway. Most turbo's I have worked w/on have had the turbo right on the end of the exhaust manifold, never a few feet off of it. Just a new configuration I have never seen, it does get my interest in seeing the #'s produced.

JG

fbarnhill

Mark,
It looks great and I anxiously await the video. I think this might be the way to go for my 79 Euro Auto. I love the car's OB stock look. This looks like a way to maintain the looks I love and get a little extra power at the same time. Let me know if there is any way I can contribute to the development of the kits for the OB autos

Herr-Kuhn

The turbine is powered by heat and pressure...the rear mount setup works but not as well as a front mount will. There is heat loss through the exhaust...you can see 200-300F across a turbine alone...this is heat energy that has gone to powering the turbo. Many people don't grasp this concept. The exhaust gas has a certain amount of energy...it is this energy that is harnessed to power the turbocharger. Less heat means less energy. Heat from a turbo 928 isn't nearly what everybody who has never seen one thinks it is. Fact is on a car like this you simply can't hold your foot in it all that long anyway.

MarkRobinson

...without spinning out right?

The entire exhaust path is only about 24" longer than a stock 944 turbo, & you can see how successful those cars are even though the path is not "ideal". It's ideal-enough, same with the 928 (my opinion)

You can always thermal-tec wrap the pipe: excellent way to harness the heat loss.