1st gen push

G

glen1

New member
I have been to a few driving schools with my 1st gen rx7 and it has a small push, or understeer. The car is set up to NASA Pro 7 specs, springs, camber kit, shocks, Toyo tires, posi rear. Any suggestions?
 
Wow! You have a small bit of understeer in a 1st gen? I wouldn't change anything except trying to make adjustments with tire pressure. Either increase the rear cold starting pressure or decrease the front. Make changes with two lb increments.
Ray
 
if you have a push in a legal NASA pro7 you have a front brake dragging, massive toe in or a flat tire. all 7's are tail happy....
 
Congratulations!

You've rid yourself of the nasty oversteer inherent to that car.

Small changes to bring it back towards neutral. I have found that a 2psi differential (changing one end only) is a rather large tuning change. Especially after you've said "okay that's better" and you try two more. Beyond a 4psi split f/r and I'd go back to even and make another change (front bar one hole softer) and start again with small pressure changes.

Off to Grandma's, Happy Easter!!!!!

On edit: When does it push?

Entering a corner?
Mid corner?
Corner exit?
Does it push going both direction?

Okay, now I'm off to Grandma's!


[This message has been edited by Quickshoe (edited April 20, 2003).]
 
Thanks for the replies. The car pushes as soon as I turn in and get on the gas, not a big push, but just enough to keep me out of trouble, but I would like to get it more neutral. I will try air pressure first, then a little bit of toe out.
 
Glen,

How tight is your posi? With the oversized clutch plates in my diff, I have a slight understeer. I run a 85 GSL-SE. The car doesn't have turn-in spacers installed.
 
What year is the chassis? I have an 85 that had a big push in Pro7 trim until I relocated the lower trailing arm to pre 83(84?) position (up 19mm)

Eric

[This message has been edited by wlfpkrcn (edited April 21, 2003).]
 
I am not sure how the posi is set up, I will try to find out. The chassis is a 1983. What do I have to do to relocate the trailing arms?
Glen
 
Originally posted by glen1:
I am not sure how the posi is set up, I will try to find out. The chassis is a 1983. What do I have to do to relocate the trailing arms?
Glen
Click to expand...

I assume your not running IT, because I beleive that would be illegal:

GCR ITCS D.5.d.8 "No other relocation or reinforcement of any suspension component or mounting point is permitted."
 
If there is a dif. in trailing arm mounting location between 79-85 cars, why would it be illegal to relocate them to any position if they are on the same spec line? Assuming that the whole assembly is replaced.
 
Originally posted by Quickshoe:
If there is a dif. in trailing arm mounting location between 79-85 cars, why would it be illegal to relocate them to any position if they are on the same spec line? Assuming that the whole assembly is replaced.
Click to expand...

If you say... drill holes in the bracket on the rear end that the t/a is attached to, to attach the trailing arm in a different location, I would think thats illegal because that would be relocating a mounting point. If you swap rear ends between the different years, then you are changing the complete assembly, regardless of where the control arms are mounted on the different year rear ends, I would think that is legal. Hope this makes sense.
I Ray Man
 
I stand very corrected, my 7 has a push as well with 1 1/8" of turn in spacers. yesterday at BWRP I was doing the open testing (with all formula cars ne less) and in star mazda turn if I got on the gas too hard at mid turn it would push bad, also would do it in turn 1. I did 300 miles of practice and boy am I sore this morning, learned alot, spun 5 times, 2 of them doing the wild thing out in the dirt at warp nine. I now understand the pucker factor of the talladega turn at BWRP, 100 mph + dirt + vertugo = max pucker factor.

------------------
Daryl Brightwell
ITA RX7 #11
SFR, NORPAC
ITA RX7 #77
CSCC, SOPAC
E/P BOTH SOON

[This message has been edited by 7'sRracing (edited April 25, 2003).]
 
I had to drill the front location point up 19mm on the lower trailing arm. It is legal in Pro7. Wouldn't that fall under the update and backdate rule. You would be backdating to an earlier mounting location or does that only work for parts? I have read the IT rule book, but not to the extent to know the rules that intimately.

E
 
Originally posted by wlfpkrcn:
I had to drill the front location point up 19mm on the lower trailing arm. It is legal in Pro7. Wouldn't that fall under the update and backdate rule. You would be backdating to an earlier mounting location or does that only work for parts?
Click to expand...

The rule goes something like this: Any updated/backdatedcomponents shall be sustituted as a complete assembly.....
Not sure about the pro7 rules but in IT, changing the pick up point of the lower control arm would be a no no.
Ray
 
whether or not this is a legal update or you have to change tubs, does anyone have a good handle on what his change does to the handeling. i thought the change on the stock car improved the geometry so why go back to the old spec.
dick
 
I believe the the old spec is better once the car has been lowered close to or at IT spec min. Still not ideal when lowered this much, but better.

I am far from being an expert in suspension set-up. It was mentioned that turn-in spacers are installed. Has a trilink system been installed? If so or even if not, give Jim Susko (sp?) at G-Force Engineering. His in depth knowledge of the 1st gen suspension should be able to assist in trying to solve some of your handling woes.
 
The change to the car was drastic. It went from a pushing pig to having to dial out all the adjustments I had tried to get oversteer before moving the links. I did not think it would have the effects it did. I know it changes pinion angle. I'm not sure of the other effects it had when cornering

E
 
I believe they changed the mounting point when they started building the SE. Maybe Mazda had a handling problem with it in stock trim, and that's how/why they changed it

E
 
I did some research and here is what I came up with. By moving the link up I increased anti-squat. Increasing anti-squat reduces roll understeer. Therefore curing my push.

So does anybody race a 84-85 chassis in IT? Since adding a panhard rod lowers the roll center on the rear end. I assume this would also reduce roll understeer. Can anyone confirm this?

E
 
You must log in or register to reply here.
Back
Top