Inherent weaknesses of FD for track use
 

Newbee here.
I plan on using my '93 RX7 for road track, racing use. What are the inherent weaknesses of these cars? Anything major that is life ending: hubs, spindles, ball joints, control arms, chassis?

Anything Prone to failure (besides engine)- as in you must do this before track?

Cooling, I can usually get a good 25-30min. session as long as its below 95.

But as far as everything else I have 500+ track miles on mine since I got it last year, and all I have have done to the suspension and brakes is changed the pads, changed the fluid, and got an alignment.

Nothing in that regard except age itself. It's a good idea to check the condition of everything in the suspension/drivetrain on any 13 year old car you're tracking, but there are no built-in problems.

Some folks have seen bending/breaking of the front sway mounts... but that's typically with stiff suspensions and R-compound tires... however, I ran those things and mine were perfect when I removed them last year.

The absolute must do's right away are clean and proper tracky-worthy brake fluid, possibly some more track-worthy pads, and a proper water temp guage to monitor temps. Heat is the enemy of your motor.

Overheating.

Yes, watch the engine temps. I've finally solved all my overheating issues (I ran for hours in 100 temps at the track last weekend with no problem) but I had to do a number of cooling modifications.

do share :)

The best cooling mod for any FD is a GTC front bumper or the like that's well ducted.

You'll run cooler than the guy with the stock bumper who upgraded both his radiator and his oil coolers.

Obviously your best approach is the bumper along with the upgrades :bigthumb:

I used to get too hot after about 10 minutes of tracking the FD if it was over 85. My last track day was in 100 degree heat and engine temps stayed fine through all six 30 minutes sessons.

I did not do any modifications to the body of the car (although as stated above I'm sure an inreased intake area would help). I didn't do anything that hasn't been written about before. It's jus that I had to do ALL of the following modifications to run cool in all conditions (not just some but ALL):

1) Larger Aluminum Radiator made by CSF (I believe it's pretty new on the market) I used a Koyo previously and I think it was too thick for good airflow. The CSF is just as large or larger but has larger gaps between the fins for improved airflow.
2) Dual Oil Cooler (stock R1 model)
3) Completely sealed off radiator. It's important that every once of air that enters the nose of the car is forced through the radiator. I used heavy duty upholstery foam and 3M spray on glue to seal all around the sides of the radiator. Kinda ghetto but effective and easy to do.
4) Removed the air conditioining. The AC condensor is not your friend. If you must keep your AC see crispy's website about how he relocated it to lay down flat against the undertray which looks effective to me. Write up here http://www.negative-camber.org/crispyrx7/cwric3.htm
5) Underdriven water pump. I think you want to underdrive the waterpump at least 25% for good high rpm coolant flow. I used a main underdrive pulley from Rotary Extreme.
6) Coolant mixture 70/30 Water to Coolant
7) Synthetic 20w50 oil at the track
8) Run the electic fans all the time at the track. Since I have no AC I can do this just by turning on the now non existant AC which caused the fans to fun constantly. You'd think that this would not help at speed as the fans provide far less air than what is being forced through the nose of the car at speeds over 30mph. However the fans seem to help underhood airflow and for some reason it really help to run them at least at speed.

Anyway... I think that's it. Works great for me!

BTW my engine and turbos are stock. I do have the M2 (ASP) Large Stock Mount Intercooler, M2 intake and downpipe

John,

thanks for a nice helpful comprehensive post that i am sure will save more than a few engines.

howard coleman

Sealing the radiator to the inlet, running a 90/10 water to coolant mix and underdriving the water pump are all I've needed to control temps. I run a completely stock powertrain other than exhaust along with a stock radiator, stock a/c and stock R1 oil coolers. I removed the stock plastic air guides in the mouth of the inlet (this makes the inlet slightly wider) and then built simple metal fences that extend from behind the sides of the nose inlet directly to the sides of the radiator. They have holes in them to allow the powersteering loop to pass through. This turns the nose inlet into a true duct with 4 sides and all air MUST now pass through the radiator. This is more efficient than merely stuffing things in the gap between the radiator core and the frame because the sides actually guide the air straight to the radiator core and will not allow the air to travel anywhere but in a straight path.

Great idea I'm going to have to try this before my next track day.

I didn't mean to under emphacize cooling mods... the original question seemed to be about "failure points" in the chassis/suspension.

To agree with everyone, heat, in everyform... oil, water, air intake, are your enemy. You can't HAVE "enough" cooling in these cars IMO...Until you can run a 30 minute session in 110 degree, 100% humidy weather, and maintain 85C water temps, 85C oil temps, and 40C AIT's at 15 psi, you could benefit from "more" cooling... :-)

yeah its hard to really know what fails if the car only runs for 5 laps without overheating!

the stock brakes do fade, if you get that far, good fresh fluid and maybe better pads...

aside from that stuff, and fixing worn out stuff (pillow balls....) they are really good

The stock twins get really hot and in some cases tend to eventually cook the water seal on the passenger side of the engine, requiring a rebuild. This happened to me at 90k miles and 160K miles.

Yes, a metal guide like you made would be great. The foam I used was heavy duty enough that I was able to cut sheets of it and duct all four sides. Holding up fine... so far.

Damn! This happened to you twice??? That's enough frustration to take some years off your life ;)

Eh, I figure 90K on the factory motor and 70K on a factory reman isn't bad. Especially if you track the car.

Whenever I need to feel good about what I spend on my FD I just go do a track day with the Porsche Club.

Done all of theese mods and recommend ducting the oil coolers,I have a visual I will share with you.
On my way to the track I stopped for gas,it was raining quite hard and about 45 degrees out,I had been cruising at freeway speeds only and while I was pumping the gas, steam was literally pouring off the front of my car! ......whoa!... whats broken?.....as I ran around the front of the car the steam was coming off the fins of the oil coolers....was cool to see and justified all the fab work,so I guess they were earning their keep :)

The stock oil cooler have pretty good ducting from the factory, don't they?

If you were referring to me John I had the poor mans track FD a pep:( so I pulled out the one cooler and installed a CWC kit.

I've been reading a lot of posts where people have said the stock oil cooling on a touring model is insufficient for HPDE events.

Has anyone experiemented with adding a water-cooling oil filter housing in addition to the one stock oil cooler? They're very inexpensive and could theoretically transfer a significant portion of the oil cooling to the water cooling system (which I have already upgraded). My GVR4 has *only* a water-cooled oil filter housing and I have 183k trouble free miles including track days on it so I know it works, but not if how well it works for our motors.

I've got two track weekends coming up in July and I don't think I've be able to upgade to dual oil coolers before then.

Any thoughts?