23Racer

Just wanted to keep up my unofficial race reports involving the #23 RX7.

This past weekend was just tons of fun (well sorta). On Friday nite we decided to swap over the tires to the race set. A stud just snapped off while undoing the nut. Grabbed the stud after it fell on the driveway and could undo the nut easily with my fingers, WTF????? Took a look at the rest and couldn't see any problems. This was really scary. To replace the stud on an RX7 you need the use of a press, a new rear axle bearing and new studs. Thanks to Scarboro Mazda, Al let me use his shop Saturday morning to fix the problem and get the car back together by Saturday afternoon.

That was a long way around to let you guys know that I was not there for Saturday Practice, Qualifying or first races. Left at 5:55 Sunday morning for the track. Registered and unloaded. As soon as the car was on the ground it started to spit rain. Previous readers of my race reports will remember that my car hates rain. It tries to kill me at least twice a race. Went out for hard luck practice just to see if my new motor would work okay. Pulled really hard up the back straight, but had some pretty big puffs on overrun and on the shifts. In the drizzle I got the thrill of passing a full on Trans Am Corvette around the outside of Turn 1. Well actually we weren't racing as it looked like he was just goofing around.

First race, Ontario Challange Cup Sprints. Started 45th out of 46 cars. Started to rain again while we were on the mock grid. Luckily I had a full soft setup on the car, but was running my intermediate tires on the rear (someone had made the executive decision not to bring the full rains, grrrrr me). Pulled out onto the track and had to use a telescope to see the front. Tried every trick in the book to generate tire temp, hard brakes and throttle at the same time and jerking the car from side to side. Came around 10 to get the start and I was trapped on the inside as a Porsche spun right in front of me. Jumped on the brakes, slid the car to the outside, crossed my fingers that the guy on my outside would see me move and give me room. Figured a side to side was better than head on, wiggled a bit and made it through. Looked to my right and saw a GT1 Monte Carlo hit the Porsche head on.

Passed 5 cars on the first lap, a number of the passes were blind as the spray was every where. Imagine 35 cars kicking up spray at 180 kmh and you are hunting for a hole a foot off the car in front and the one beside you. Passed 3 cars on the second lap but got baulked behind this GT 1 Corvette that was being driven excrutiatingly erratically poorly. He would hammer up the straights and block like mad in the corners. As I drove down his inside into 9 he turned in on me. I had to stab the brakes and almost spin it as I drove up on the inside curbing. 2 cars that i had previously passed repassed me as my life passed before my eyes as I practiced drifting through 10. By this time the track was starting to develop a sorta dry line and I could use more of my power and cornering ability. Had a great race with an old school Mini for a few laps until the track dried out enough that he became speed limited at about 170 kmh and I could get to about 200 kmh going into 8. He was geared so that he could pull about 5 to 6 car lengths and I would march down on him at the ends of the straights. My windshield was opaque by this point and I knew that I had another race to do so backed off and kept position to the finish. One last thrill as I came out of 2 in an oversteer slide and found a Viper bacward on the track just off on the left. The track was biting people all race as the conditions were really inconsistent. Ended up 23rd out of the actual 36 starters. Not a bad result as 10 cars didn't even make the start due to the before the start accident and a bunch of rain hating wimps staying dry in their trucks.

The Touring race was even better, but that will be following.

Snrub

iTrader: (1)

Man you certainly take the glamour out of racing in the rain. What have you done to make your car better able to handle wet conditions other than tires and soft setup? For example, how do you see going 180km/h in the spray?

01Racing

Thats exactly why I stayed home! With good wipers and lots of rain X you can see okay in the rain at speed.

Feds

Al, you should have seen Eric's car after too!

You would have been cleaning that sucker for a month! Dirty dirty!

johnf

I was there on Sunday & I would say you looked pretty good out there compared to most - the rain really mixes up the cars & makes for interesting racing. The next event is on the weekend of Aug. 27, will you be there?

23Racer

To soften the car quickly for the rain we undo both of the front and rear swaybars (to allow more weight transfer to the outside wheels). This gives the outside wheels a lot of grip, well, compared to with the bars hooked up. This also reduces some of the twitchiness as it slows cars reactions to driver inputs, sorta a driver dolby. We also soften the rear shocks up a ton to improve (allow more) rear end squat. This minimizes power on oversteer coming out of the slower corners.

Regarding seeing at 180 kmh in the spray, quickly stated, you can't see 5 feet beyond your front bumper. You have to trust that nobody else does something stupid. As it starts to dry up you get a ton of road grime on your windshield, like in winter when you get dried salt spray on your windshield. You can barely see through the grime. I could have gone a bit faster at the end of the first race but it is hard to find apex points at 170 kmh when you can't see. This is when experience helps a ton. You can tell what you need to do by looking out of the side windows.

I have actually found my RX7 to be one of the worst cars I have ever raced in the rain. When I lowered the car it created a ton of transient bump steer conditions as the suspension moves through its operating range. In the dry the car is very stiff so the effects are minimized. In the rain, with the bars disconnected and the shocks set much softer, the car develops some momentary toe out conditions that cause some snap oversteer moments. That is why I always say that this car tries to kill me at least once a race in the rain.

Regarding the dirt, the car is VERY VERY DIRTY, but now that it is dry it sorta has a Le Mans 24 Hour look to it. I should just do what Mazda did with their 24 Hour winning 787B and just coat the car with clear and display it in my living room.

No I will not be at the August 28th weekend races as I have to fix an oil pressure issue, but if the motor is still good I will be out for the Touring GT race during the ALMS Weekend.

Snrub

iTrader: (1)

Wierd. Isn't it possible to use smaller bump stops? Could you explain why is better to have the car dangerously twitchy than simply stiff? Wouldn't it make sense to raise the car slightly and perhaps lower the tire pressure?

20B-3Rotor

I notice you car had alot of blue smoke when entering corner 2 where i was watching the race.

23Racer

Re: Blue Smoke. It was smoking like a pig all day Sunday. We only had 1 small crankcase vent tube hooked up and the other one was plugged, so we think that we were pressuring the crankcase and when the engine was on overrun the vacuum pulled the oil past the less than optimal oil control seals.

I also dumped a bunch (3 liters of oil) of extra oil into the pan Sunday when we realized that I couldn't reach the Accusump to turn it off after the warm up session on Sunday. I am hoping that either one of those things are the cause and not completely blown oil seals. It was really blowing out blue on the overrun and during shifts, but the engine was pulling really strong so I have my fingers crossed that we can fix it by looking at improving the pan ventilation. I also am dealing with an erratic oil pressure issue as well so I hope that it doesn't mean that this engine is on its way out (fingers crossed tightly). I am pulling the oil pan and front cover this week to determine the potential causes.

Re: Bump Steer. When I am talking about bump steer I am not talking about the car hitting the bump stops. Bump steer happens when the suspension goes through motion induced toe changes due to less than optimal realitionships between toe rods and control arms. This usually happens when you lower the car and the control arms raise up in relation to the steering rack or toe control links. This changes the operating swing relationship between these parts.

Raising the car, to restore factory designed relationships, would be the smart thing, but in the dry the lowering effects are liveable with the big bars. Also I usually don't adjust tire pressure a ton. Toyo's provide their most stable contact patch when the tire pressure is in the 40 psi hot range. As well you really need to get tire tread temps close to 180 degrees before the compound is really starting to work. In the rain you will never generate 180 degrees of tire temp and you do require additional grip, so you do sacrifice some lateral stability by reducung tire pressures. We usually drop the effective tire pressures by about 5 lbs from our usual dry starting pressures.

Very good questions and observations. My big concern right now is trying to determine the condition of this motor.