Dave DE

I've been hearing stories of Caymans and Boxsters with power steering failures related to overheating at track events. It sounds like the best fix for this is an underdrive pulley or a cooler added to the PS installed in the center vent area at the front of the car. Since I only do an occasional track event, and I am not experienced enough to really push things, I recently took a look under the car hoping I could come up with something simple that might help the situation a little bit without as much trouble and expense.

Looking at the pic of the PS lines, you can see there are a few loops in the line at the center of the car to serve as a heat radiator. There is a NACA style duct in the plastic bottom cover to cool this area. Note that there is another single loop outboard of the other ones. There does not appear to be any airflow through this area. Just ahead of the single loop is a mounting screw recess in the cover. I cut a hole in the trailing edge of this recess to bring air into the cavity. I also added a rectangular vent further back to allow the air to flow out, and was also thinking this might help cooling when the car is stationary.

I don't claim that this will make a major difference, but it seems to me it should help a little bit and it was easy enough to do.

Dave
'06 CS

FTS

Dave, I guess you and I have been having our own little cooling issues. This looks interesting. I have not had the PS issue yet, but I'll keep this one in mind; let us know how it turns out after few track days.

smayster

I have a 2002 Boxster S that I track pretty often (15-20 days/year). In the past 2 years, I've been through 2 power steering pumps, one fluid reservoir, and a high pressure line.

Last month at the Shenandoah Circuit at Summit Point -a VERY busy track with 16 turns in less than 2 miles- the low-pressure return line became uncoupled from the reservoir, spilling fluid all over the engine compartment and killing the pump. It seems the reservoir around the coupling most likely melted, which caused the failure.

Obviously, I'm now exploring alternatives. The other option I've come across is an underdrive pulley off the crankshaft that will slow down all the pumps, as well as the alternator. I've heard this works great for the track, but may cause problems under normal driving, as the alternator may not get the required rpms.

Adding ventilation to the undertray seems like a very viable alternative... but does anyone have any feedback on whether this works? This is tough to judge, since if it does work, nothing will happen! I guess it's easier to ask whether anyone has done this and STILL blown a PS pump.

Dave DE

In my research, I've read positive reports from people who have installed an underdrive pulley or the front mount cooler, so I would consider those to be proven fixes. I have not heard of anyone trying extra undertray cooling before, so it is an unknown. One way to look at it would be to compare the length of tube exposed to airflow. I'd guess there's about a 50% increase in tubing exposed, assuming the new intake vent works fairly well. I tried to come up with a reliable temperature measurement I could take to compare with and without the added vent, but it gets complicated trying to simulate track conditions when you are not at the track...

Dave

insite

i second that. Mantis Sport out of Canada campaigns a Cayman in PCA. they created the underdrive pulley to solve the power steering issue. another benefit is the additional 6HP. the part is around $350 Canadian. what's that in real money?

smayster

Yeah, that's the pulley I'm looking at. I was just in Toronto last weekend, and I hate to say it, but it's like $.95 to the CAD now. Not quite like it used to be!

Anyway, the pulley seems like the most economical and reasonable answer, but my concern is that I also use my Boxster on the road. Don't want to kill my battery with a slow-running alternator! Anyone hear any feedback on that?

mooty

the pulley is one fix, but it slows down everthing, like AC which is important to me.

anyone thought about usiing 997 cup car pwr steering? it's electric.

insite

the mantis guys say that the ancilliaries still work fine at the slightly reduced speed. as for the electric power steering, interesting. in know of some guys that have added honda electric power steering pumps to the box. it works, but they say it doesn't feel quite right. maybe the cup car setup would feel good...

smayster

Having a convertible, AC isn't as important but the alternator is. I'd like to be able to hear from someone besides the manufacturer that the battery gets enough charge under normal driving (not that I usually have the rpms under 2.5K!)

FTS

Well, I will be at Shenandoah this weekend for the first time; we'll see how 987's PS compares to 986's. PS failure is the last thing I need right now frankly.

FTS

Well, Shenandoah went pretty well today. It was a relatively hot 85-90, but with low humidity. The car performed flawlessly, no issues with PS and especially with brakes, thank God. Also, there were many novices as well as first timers on the track, but we haven't had a single off-road or crash

Tomorrow is another day though, we'll see how we come out of the weekend

Dave DE

Glad to hear things went well at Summit. I attended a PCA tech session today and took a look at a 987 box on the lift. While everyone else was looking at the engine I was looking further forward. Confirmed that all the cooling stuff is the same on it. Also looked under a 996 TT, and did not see any PS cooler on it. The lines are more exposed since the plastic panels do not cover the entire belly, but I didn't see loops like they have on the CS. Brake wings were the same size on the TT, but there are openings in the front air dam to funnel air into them that are not present on the CS.

Have fun!
Dave

Jim in St.Louis

So Porsche makes race cars and puts a timing device for track times as an option, but they don't have a solution to p/s over heating? Does anyone else find this very disappointing?
Jim

FTS

I guess they did, by making the lines longer to hold more fluid.

Every car has weird sides to itself, sometime part of the charm, other times huge annoyance

Yes, second day went great as well, no mechanical issues of any kind; and brakes were really fantastic, additional cooling, especially in Shenandoah, helped.

Track Junkie

The problem of the Cayman S power steering failure seems to be the result of lots of negative camber and resulting positive caster.
The greater postive caster increases the steering effort and increases the work load for the power steering pump, extra heat and melted plastic fittings.
Those that report problems are using lots of negative camber, - 3 degrees for some.
Less negative camber should minimize the rate of failure.