During my last autocross I ran across an odd problem. I've experienced it before, but didn't pay it enough attention. It was a particularly long, tight course -- lots and lots of steering. Anyway, everytime I reached one of the last turns before finish, my steering wheel felt super heavy. I had to use all my strength to make a tight corner near finish, and damn it slowed me down.

So I asked a veteran autocrosser what he thought. He asked if I've checked power steering fluid. No, I had not. He told me I need to look into it. He thinks the fluid is either low or overheating. Another guy said his power steering fluid on his old car used to overheat on every run, and it would exhibit the same problem. After checking my fluid, I saw that it was not low, and that it is at the proper fill level, according to the owner's manual.

I don't like effing around with my car. I like driving it. Hence, my cluelessness. Does the above explanation sound plausible? Does anyone suggest synthetic power steering fluid to cure the problem?

 

i think you need a power steering cooler kit. Nismo has one for $150.00.

http://www.nissanusa.com/nismo/

i hope this helps

 

Our Corvette would start to whine when it got hot. Switched to Redline fluid and the problem went away. No idea if that will help your Z but it is a cheap fix if it works.

 

I've heard of people boiling/overheating their PS fluid on the track but never during an autocross. The run time is not that long and the amount of steering not that much that it would typically cause overheating.

Check the fluid level to make sure there is enough in there and it's clean. Otherwise it shouldn't be a problem.

One other thing you can check is to make sure the belt it tight. If it's loose and slipping under the load, then you might have decreased steering function.

 

Another thing that I've found is that removing the front plate helps get more air into the engine and I haven't had any problems with overheating PS fluid since I started doing that. (knock on wood!)

 

I have a little boil over on the track, but do not notice steering behavior changes. Try removing the black plastic things on either side of the grill opening. See thread: https://my350z.com/forum/showthread....light=thingies
Radiator thingies

 

Just for the record, both of these suggestions are illegal in SCCA Stock class:

 

I overheated the stock fluid on the track and then changed to redline PS fluid. I would suggest changing the fluid first before trying anything else.
There is a thead in this section (autocross/road) about it and tell you the easiest wat to change the fluid - basically pump out of the reservoir and replace fluid - drive car - do it again...

 

i did not know , sorry.

 

I'd suspect something like the PS pump is not working as it should! I'm not sure how to test the PS pump but it would be a starting point...

 

Thanks for all the suggestions and insight. It's going in service tomorrow to have some work done. While it's there, I'll ask them to look into making sure the belt is tight, and give me a price for replacing the fluid with synthetic. I've not yet looked into the black plastic things, but I shall.

I've given up on staying in B Stock, so I don't care what class it puts me in. My ambition with autocrossing at the regional level is merely to be the quickest on street tires - a goal I rarely acheive, but second or third ain't too bad either, and that's usually where I end up!

 

Well, if you get outside of BS with street tires, then you'll have an even harder time reaching that goal. I did pretty good on the stock Potenzas in BS but was a good 6-8 seconds behind the cars in BSP - the next step up from BS.

 

I had/have the same problem.
Got my car back from the dealer today. They said the front was toed out causing additional stress on the steering which caused the problem. It needed new alignment specs per TSB, and the outside of my front tires were worn enough to warrant free replacement.

Not sure that I believe that was the cause, but I guess I will see what happens.

 

I had/have this prob. too. It occurred during high temps in the summer so I attributed it to that and haven't competed since. I was thinking of getting the cooler too. Now I'm wondering if it has to do w/ that odd system that we have that adjusts the feel of the steering based on your speed.

 

Funny, I was going to post about this same issue today (I hadn't seen the thread).

I had it happen several times this summer in Solo2 when there's lots of quick tight turns, the power steering would momentarily give out. I've only had this happen with R compounds, never streets in the 3 years I've had this car.

Thinking the fluid was old, I had a buddy at a garage check out the fluid and he said it looked great.

 

Yes, a fluid upgrade helps 90% of the time!

 

Just swap the OEM cooler for the longer Nismo one and be done with it!

I've heard plenty of Autoxers with that problem but not on full race track (airflow and less steering input?)