As I understand it the first gen can create some lift at speed. at what speed does a stock rx7 start to become a little to light?

 

Not at 116...


Stu Aull
80GS
Alaska

 

Mini gets light around 110 or so. Stock suspension suspension can make it worse.

 

Thanks, I used to have a Mazda urethane IMSA air dam on my 81, but for my 80 I want to keep it looking stock as possible. Just looking at limitations and hazards of top end.

 

.....bilsteins and konis on mine + 205/13s, if we are mentioning suspension bits equipment...

Stu Aull
80GS
Alaska

 

I'm with you on keeping the SA stock. I would jave put a duck bill on it ages ago to cure this if I went
that fast on a regular basis like at the track.

 

On my stock front end SA, lift started at around 100-105mph in clean air and no wind, and got steadily worse with steering lightness and drift at anything above that. I had the speedo regeared to show up to 155mph top end (unrealistic, but better than 85mph stock) and calculating error, the car was much more controlable up to about 115-120 with a Kamei airdam. Anything to keep the air from pushing up on the lower valence helped immensely.

The Mariah Mode4 likely keeps even more air from making lift on my -SE and a rear spoiler seems to help at high speed, too. I never noticed rear end lift, but theres a lot going on with the car at that kind of speed to pay attention to anything in particular.

Only do this speed in a straight line, as the cornering forces are very likely to unsettle the car.

*statute of limitations is LONG past on this one! I have no need to drive that fast anymore...

 

Yeah they get light. Going around the back of Phillip island race course where its long blind sweepers over a crest at near 200kmh gave the term "Wonder Steer" new meaning, literally no feel or control other than the forces of inertia already set in motion. Had crappy cut spring and KYB suspension and no air dam last time i was there though. Might be better now.

 

What happens out of curiosity, steering gets light and loses feel due to the loss of grip on the front tires?

 

Yeah,just felt like the steering wheel wasn't connected to anything. It's a light part of the track, but its supposed to be held flat. (scary for novice like myself). Wouldnt call the car unstable though. Was fine on the straight nearly topping out 5th gear when you arent asking the front wheels to do anything in particular.

 

Interesting, thanks for sharing. I suppose that's why all of the 70's/80's endurance racers ran some sort of modified front bumper.

 

Mine's lowered 2" and don't really feel the front wander. Have had it up to 120mph with no issues. Unless there is wind.
At ACS coming off turn 2. with wind. It's moves up the track if there it wind. But it's not bad.

 

It's in French, but you can figure it out:
* Red = low pressure air
* Blue = high pressure air, note windshield vent intake in high pressure area
Also note that this shows 2 profiles; one for the stock body, and one with rear lip spoiler.