Inter-cooler question

James Rogerson

James Rogerson

Well-known member
David Koller's STU car is in the shop (Solstice) and the top row of the inter-cooler is ballooned up like crazy. It's as if the thing was stopped up. Anyone seen this type of behavior?

James Rogerson
 
That's cause he pushed that turbo boost button on his steering wheel too many times trying to stay ahead of me at TMS!! (Larry will get a kick out of that at least..)
 
Such a failure is a manufacturing defect. The inner fins either failed under tension (the inner fin is what holds the tube together when inder pressure). This is unlikely unless you see 50+ psi of boost. More likely there was a poor to non existant bond between the inner fin and the inside of the tube.
 
The ballooned intercoolers are somewhat common even on street Solstices with increased boost. There are vendors on the Solstice forum that sell aftermarket intercoolers. Some of the aftermarket tunes get them up to 25+ psi.

http://www.solsticeforum.com/
 
I did some more checking and found the stock setting on the waste gate. Crap it was almost double. I've dialed it back in and if the rains hold off tomorrow I'll do some testing and see how it holds up.

Thanks for the input,

James
 
The car has (or should have!) an inlet restrictor in the turbo, which should limit airflow/boost at the top end. tons of torque, but they get choked down at the top end.
 
STU and T2 both require turbo restricter. I ran the car and did 1.5 seconds under the current T2 track record in STU trim (more weight and smaller wheel package). My guestimate on the rod length proved out to be indicated 23 PSI in 3rd, 4th, and 5th and one spike at 24 PSI in 2nd gear. Had a spare stock intercooler and put it on. With the restricter I don't see any benefit to spinning the engine up to hear it make noise and intake heat. Intake heat has to be what distorted the intercooler.

We'll need to put it on the dyno to confirm that my butt dyno is calibrated.

What I notice more than anything is the lag when I run it up to redline compared to short shifting. I'm thinking it could probably use a smaller cooler to reduce lag and just short shift it.

Engine water temp never got over 210 with the more stock setup. Before it was running 245+

James
 
Watch the data for spark retard on the longest pull, with the current big cooler. make a good number of passes or pulls, until the heat and power #s have stabilized.(lowest readings)
Swap the cooler and retry. You should find better hot pulls with more cooler BTU, iMHO
Often the end of the race for boosted cars will be a couple of seconds slower due to intake temp. Of course we are looking for the best distance over time, usually 30 min for the Road racers.
I run the biggest cooler than can be tolerated by the lag and fitment, and spray it. ( VW Chumpcar @ 11# max, for 14 hr races. )
We found longer engine life with some higher RPM than first thought reasonable. (based on the dyno data) .The results brought speculations/conclusions that the engine will make only so much power but making the same power spread over more revolutions, lowers the average cylinder pressure. More air flow runs a bit cooler at the same power output also.
Spinning the engine higher reduced the head gasket, and piston ringland failure rate.(6600rpm Merkur, 7000- VW)
Please tell us what you find, Thanks, MM
 
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