986 Forum - The Community for Porsche Boxster & Cayman Owners - View Single Post - 986 Boxster ChampCar Endurance racing build

Endurance Racer · 02-10-2022, 11:15 AM

All

Thanks for the great feedback and information. Let’s discuss further.

Engine cooling: I have removed the drivers side front radiator fan for weight reduction. The passenger side front rad fan remains for times where the car is stopped. Third radiator in the front adds weight that I want to avoid. I plan to use the lower temp thermostat.
Engine compartment is cooled from ducted air from Passenger side air vent.

Engine oil cooler: I will look into the 996/997s cooler. If its bolt in than that’s simple and easy enough. I know oil to water is more efficient than oil (liquid) to air coolers however the delta temperature is greater with oil to air. Assume oil to water would be 235 (oil) to 190 (water) where oil to air would be 235 to 100 (air) temp Assuming hot day and ambient air around the engine like in the trunk. Thoughts on this?

The Tip cooler appear to have a vacuum actuation valve to control the coolant flow. If I’m correct I would like to replace with an electric solenoid valve. As with engine oil cooling, do I go with 996/997s oil to water (will it also swap) or oil to air with greater delta T?

Accusump: Yes lots of debate and info out there. Goal here is to save the engine from high G force oil starvation.. I’m not 100% sold. Per the rules the Accusump is 10 points and a baffled oil pan is 20 points. If I run with the Trans cooler and Engine cooler (anything other than stock) I can only afford the 10 points for the Accusump. So I thought I would try that. Thoughts? Is anything really required?

Tire size: In this series most are running a square 255. I want square for the convenience of rotating tires and can use any spare tire on any corner of the car. Also I want to have balanced grip and be able to get the car to rotate. I’m concerned with larger rear tires (than the front) I will induce too much understeer. Since I can’t change suspension, sway bars, shocks or springs other than aftermarket replacement parts like the Bilstein pro shocks and springs (which I plan to use) I need to achieve balance with tire size and air pressures. And because this is an automatic and acceleration is not as good as the manual, the large wide 275 is to have higher corning grip to have corning speed. Thoughts?

Intake: The intake must remain stock. I can remove parts like the intake resonance air induction valve but that should actually be beneficial to me to boost low rpm response. I will check out your (@Ike84) DYI short ram intake. If it is done without adding parts its possible without points.

Tune: Tune is free. No points so its free HP that I need to take advantage of. Same with at trans tune for the Tip if you know any experts on that. So with stock intake (perhaps your DYI Ram runner), Cats are gone, SAI is gone and my fabricated exhaust with high flow mufflers I need to unlock as much HP as I can.

Exhaust: Thx. I will run with high flow muffler one per side.

Other thoughts? Keep them coming.

02-10-2022, 11:15 AM	#12
Endurance Racer Registered User Join Date: Nov 2021 Location: Webster NY Posts: 69	All Thanks for the great feedback and information. Let’s discuss further. Engine cooling: I have removed the drivers side front radiator fan for weight reduction. The passenger side front rad fan remains for times where the car is stopped. Third radiator in the front adds weight that I want to avoid. I plan to use the lower temp thermostat. Engine compartment is cooled from ducted air from Passenger side air vent. Engine oil cooler: I will look into the 996/997s cooler. If its bolt in than that’s simple and easy enough. I know oil to water is more efficient than oil (liquid) to air coolers however the delta temperature is greater with oil to air. Assume oil to water would be 235 (oil) to 190 (water) where oil to air would be 235 to 100 (air) temp Assuming hot day and ambient air around the engine like in the trunk. Thoughts on this? The Tip cooler appear to have a vacuum actuation valve to control the coolant flow. If I’m correct I would like to replace with an electric solenoid valve. As with engine oil cooling, do I go with 996/997s oil to water (will it also swap) or oil to air with greater delta T? Accusump: Yes lots of debate and info out there. Goal here is to save the engine from high G force oil starvation.. I’m not 100% sold. Per the rules the Accusump is 10 points and a baffled oil pan is 20 points. If I run with the Trans cooler and Engine cooler (anything other than stock) I can only afford the 10 points for the Accusump. So I thought I would try that. Thoughts? Is anything really required? Tire size: In this series most are running a square 255. I want square for the convenience of rotating tires and can use any spare tire on any corner of the car. Also I want to have balanced grip and be able to get the car to rotate. I’m concerned with larger rear tires (than the front) I will induce too much understeer. Since I can’t change suspension, sway bars, shocks or springs other than aftermarket replacement parts like the Bilstein pro shocks and springs (which I plan to use) I need to achieve balance with tire size and air pressures. And because this is an automatic and acceleration is not as good as the manual, the large wide 275 is to have higher corning grip to have corning speed. Thoughts? Intake: The intake must remain stock. I can remove parts like the intake resonance air induction valve but that should actually be beneficial to me to boost low rpm response. I will check out your (@Ike84) DYI short ram intake. If it is done without adding parts its possible without points. Tune: Tune is free. No points so its free HP that I need to take advantage of. Same with at trans tune for the Tip if you know any experts on that. So with stock intake (perhaps your DYI Ram runner), Cats are gone, SAI is gone and my fabricated exhaust with high flow mufflers I need to unlock as much HP as I can. Exhaust: Thx. I will run with high flow muffler one per side. Other thoughts? Keep them coming.