986 Boxster ChampCar Endurance racing build

[Endurance Racer]

Originally Posted by 78F350

I have a DME-Immobilizer set from a 2004 2.7L Tiptronic that I can loan you if that helps. I am open to selling it if it works for you.

Thanks I really appreciate that, but its not going to work.

I believe I will need DME with Immobilizer and key together or it will not start.

Or replacement DME will need to be reflashed to work this my Immobilizer and key. I don't know of a source or person that has the capability to do that.

:

[78F350]

To clarify, This is what I have:

https://www.ebay.com/itm/155065766086?nma=true&si=MmbRQ601PC5CgEY138kHApcbDZY%253D&orig_cvip=true&nordt=true&rt=nc&_trksid=p2047675.l2557


I bought it from that seller off eBay. It's currently in a 2004 2.7L car that runs, but shows an error for ABS coding. If nothing else, I figure that it could help with your diagnosis and only cost shipping to try it out.
To test your car, I would send the DME, Central locking module (immobilizer box), and the key fob - which houses the transponder for the immobilizer. It is from a Tiptronic car, but should be able to run the engine in your car - is the DME in your car the original Tiptronic?

I also have a DME and immobilizer box that originally came with the '04 2.7L car, but no key fob to go with it.

[78F350]

Mrs 78F350 is dropping it off for shipping it as I type. Here's what is being sent:



The VIN that it is coded for shows a 2003 2.7L Tiptronic.

The transponder is inside the key fob. I'm not sure how your ignition is set up on the race car, but you can put your key blade in the fob, or just have it in position at the ignition when you turn your key - I expect that your original key fob will interfere if both are in proximity at the same time.

[Endurance Racer]

Well I'm at a loss battling the p0336 code.
Many thanks to @78F350 for lending me his DME, Immobilizer and transponder (key pill). I got the car to run with this loaner DME but still have the P0336 error.

I've checked the engine mechanical timing (all 4 cams and crank positions), the crank sensor (2 of them), the wiring to the DME and now a second DME.

I get RPM output on the tach and on the scan tool.

But still have an error.

[Endurance Racer]

Problem found.
I need to pull the transmission to get to the flywheel to see exactly what happened. Crank sensor had no damage.

:dance::dance:

[Endurance Racer]

Since I have to get a new flywheel, does anyone have a recommendation for a nice light weight flywheel?

[seningen]

Originally Posted by Endurance Racer

Since I have to get a new flywheel, does anyone have a recommendation for a nice light weight flywheel?

AASCO is what most spec boxster folks use

[Endurance Racer]

I'm reading that some don't think a lightweight low mass flywheel is a good idea becuase the engine vibrations lead to crank shaft failures.

[Quadcammer]

some dispute on that. Jake Raby, the so called god of the m96/m97 says not to use it, but plenty of race cars are so equipped with no real issues. just depends on your risk tolerance.

[a914Freak]

Originally Posted by Endurance Racer

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.

There is no shift kit for the TIP but I have a guy that knows how to modify the valve body for track racing,

BTW this has to be the lightest Boxster I've seen and I race one in Champcar as well and live in the next town over from guys that build Boxster race cars. (Rockwell Auto Development) are you running a Lexan windscreen?

[Endurance Racer]

Originally Posted by a914Freak

There is no shift kit for the TIP but I have a guy that knows how to modify the valve body for track racing,

BTW this has to be the lightest Boxster I've seen and I race one in Champcar as well and live in the next town over from guys that build Boxster race cars. (Rockwell Auto Development) are you running a Lexan windscreen?

Yes to the Polycarbonate windshield.
Thanks for the valve body tuning tip, but I've moved on from the Tip. Its a manual now.
With the 2.7L we will take 2 penalty laps so future plan is to swap a 2.5L into it.

[Endurance Racer]

Hi All,

Time for a quick up date. With the car converted to a manual 5 speed and the crank sensor issue resolved, we went back to WGI. Man, I love this car. The braking and handling are just outstanding. So much nicer than the 944's. But not without issues. I think its cursed. We developed a fuel pressure issue. Only getting 40psi from the returnless 65psi system. Looking at pump, regulator or the in tank filter.

We ran the Continental Extreme Contact Force Tires. I could drive this thing anywhere on the track which was handy as there were 110 or so cars on track. I really like these tires. If you want to try these you can use my discount code SOFIANEKVIP You get 4 tires for the price of 3 with this discount. https://trackdaytire.com/continentalpreorder/

But, man is it fun when its running. At less with the 944's we got a 1st, 3rd, 4th and 6th with the 2 cars and 2 days of racing.