Ok all you racers! Tell me why all the panard bars I see on RX-7's are as low as the bottom of the rims in the rear, while all the road race stock cars have the bar close to the horz center line of the rear axle. Are they there on a REX because thats the only place they'll fit, or is there some roll center vo-do that says mount them low. Must be a reason, or all they all copys of the very first one.

 

Dick, the height of the panhard bar will provide the rear roll center height. My 1st gen bar lowest position is approx at height with the bottom of the center of the Banjo. I can adjust up 3 spaces at 1 1/2 inch each space. From memory if ya mount the bar as low as the outside diameter of your rim ya better not do any agricultural experimentation cause your going to rip the bar off. Ya also mount the bar on the chassis side relative to the specific tracks you run so that the roll center is lowered as you turn for the majority of the corners.

Anyone have an automatic transmission counter weight from a 1985 12A RX-7 that you would like to sell ?

Have Fun
David

 

David! Have you tryed that 79 intake I sent you? Send me some pictures of your bar set up if you can. I'll PM you my e-mail address. Thanks.

 

David! Try Chris Taylor on the spec-7 web site.
Anyone have an automatic transmission counter weight from a 1985 12A RX-7 that you would like to sell ?

Have Fun
David[/QUOTE]

 

Hmmmmm.... if it were anyone else I'd be suspect.... now I'm just curious what's in the works. Preping for the GP green light????

 

Hold your breath on the GP green light. I really can't imagine them doing it although if they do I will be right out there.

 

Come on Scott!!! Answer my orginal question about the panard bar. ANY ONE????

 

***Preping for the GP green light????***

How about a CHEAP E car just to make a point with reference to the SCCA Fastrack response "Creating another level of prep is incosistent with class philosophy". That response IMHJ is a we don't want a non-ported motor because it's a true LP IT motor & that's where the whole deal started in 1996/1997 with the 1st egn RX-7 as the platform car only it's ported.

Have Fun
David

 

Other than the NASCAR part of the question, DD covered it as much as I know about it.

 

My "slightly" educated guess on the panhard bar height would lead me to the front end of the car. When Jim Susko and I were working together on these cars I recall the front roll center height and then the roll axis kind of made the low bar the way to go. The cars have pretty darn close to 50/50 weight even when stripped for racing and the only difference for sprung weight is the rear end weight itself. Having the roll axis close to parallel to the ground just works.
As for why the stockcar guys go higher up, dunno. It could be all the power they have, the spring rates they run on those fat pigs and how much roll stiffness they want to get from them or somebody was fast with that set-up and they all copied it. The last guess is way out there because of all the money that gets thrown at those cars.

 

Bump

 

Pick up the October 2006 issue of "Racecar engineering" magazine, there's a description of the effects of panhard bar location on the last page in the Q&A. It's quite technical.