2nd Gen ride height

[BrianB]

ITS minimum ride height is 5"from the lowest point of the rocker. I'm wondering if there are any suspension geometry/bottoming problems at this height? If so, what is the minimum and how contingent is that on spring rate?
BB

[ITSRX7]

We had the 04 car chew up the left front inner fender the first year after many events at LRP. Nick Leverone was running the car at minimum ride height. Adjustments since then:

WAY stiffer springs
Revalved shocks
Slightly raised ride height

Height can be seen at http://the16v.com/images/082502nhis/default.html on a victory lap.

AB

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Andy Bettencourt
06 ITS RX-7
FlatOut Motorsports

[This message has been edited by ITSRX7 (edited October 08, 2002).]

[BrianB]

Andy,
I've worn a hole through in the same spot. Don't know if it's the compression at the uphill turn or at downhill turn or both. Until I can afford better shocks, I'll see what slightly stiffer springs and swaybar will do. Regardless of the spring rate, somewhat softer in the rear relative to the front seems to work.
See you on Sat.
BB

[BALLZOUT]

Taller is better!!! My set up-is way up, my rockers are well over 6 inches, and on Kumhos I'm doing as good a Hoosier- lowered top Cal Club car in ALL of the corners( just can't seem to keep it on the straights) Try it you'll see 1 Rick

[Karl Bocchieri]

First, your allowed to remove the plastic inner fenders, that frees up some room and prevents alot of tire rub.
Second generation cars seem to do better if there not slamed down on the ground. I always set my front up so the tie rod ends are close to level, then adjust the rear to get the corner weights close.
I understand that your trying to get the CG lower but if you go too low you screw up the suspension geometery and the car does not work.

[BrianB]

Karl,
Thanks for your input!What spring rates are you running?When you run at Limerock, does the downhill turn determine that rate?
Thanks,BB

[ITSRX7]

Brian,

I think the uphill develops the most left front compression.

AB

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Andy Bettencourt
06 ITS RX-7
FlatOut Motorsports
New England Region
[email protected]

[Karl Bocchieri]

I run 375-400# front and 250-275# rear, this is what Mazda Motorsports sells in their kit. Lime Rock Park is very bumpy since they put in the concrete patches so you need good shocks to soak up the movement of your suspension.

[BrianB]

Karl,
Thanks for your reply!
My car has been a work in progress, autocross and track car to date. I hope to be ready for schools and ITS this spring. I've been running 325# front,225# rear,stock sport bar front, no bar in the rear.I'm running Tokico Illuminas (adjustable) shocks which are said to be limited to lower spring rates. I'll increase the rate to 400# front,250# rear and go with a ST bar in the front and see how the shocks hold up.I'm not sure what to move up to in the shock dept.Koni's ,Advance design...?At this point I'm working to get a relatively good set up and some good tires and see how I do.
I was at Lime Rock on the 25th of Oct. for a BMW driving school. It was a about a 50 degree day. Early in a session and just past the apex on the downhill turn, the rear end came around quickly and unexpected. I ended up in the tire wall near B paddock. Not much damage,but what concerns me most is why? Could have been slighly off line...there's a bump, cold track, tires not up to temp,came in to fast,suspension travel? I'm not sure why, but am curious if other RX-7 drivers have experienced this?
BB

[lateapex911]

Originally posted by BrianB:
Karl,
Thanks for your reply!
.......at Lime Rock on the 25th of Oct. for a BMW driving school. It was a about a 50 degree day. Early in a session and just past the apex on the downhill turn, the rear end came around quickly and unexpected. I ended up in the tire wall near B paddock. Not much damage,but what concerns me most is why? Could have been slighly off line...there's a bump, cold track, tires not up to temp,came in to fast,suspension travel? I'm not sure why, but am curious if other RX-7 drivers have experienced this?
BB

Well, in the 1st gen car, problems like that are often associated with binding, but as your is a 2nd gen, we can eliminate THAT!

The downhill at Lime Rock is an interesting corner. It starts off with about 1 degree of camber at turn in, then increases to about 4 degrees, then there's a slight wave there, and the camber goes away, just past the apex or so, winding up as a negative camber of 1.5 degrees or so.

So thats the track info. Maybe it's the "straw". Often these things are a combinaton of events that happen to align. In this case, the off camber change of the track, and the fact that maybe you were more "on the edge" than you thought, due to the cold and cold tires. (Hoosiers? I can attest to their absolute junk nature when they're cold!) I would take a look at your rear wheel alignment (you guys can do that, right?) and all the bolts holding things down. (I found a toe change of 1/4 inch after the NHIS event this summer, loose strut bolts...how long had that wheel been flopping around like that?). Then I'd double check the shock, side by side with the opposite corner. Finally, the problem might not be at the rear! Scale it, and check the other corners for the same sort of things!


Glad to hear the tire wall was kind and nobody gathered you up!


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Jake Gulick
ITA 57 RX-7
New England Region
[email protected]

[BrianB]

Thanks Jake,
The tires were old and probably still cold and minutes before I was a passenger in a ZO6 with a pro driver turning 1:00 or less laps. I may have been more warmed up than my tires. Like you said,"often these things are a combination of events that align".
BB

[lateapex911]

Originally posted by BrianB:
Thanks Jake,
....minutes before I was a passenger in a ZO6 with a pro driver turning 1:00 or less laps. I may have been more warmed up than my tires......
BB

Ahhhhh....the right seat phenomenon! I bet a 1:00 lap from the right seat feels like a :56! Anytime I'm in a car with a good driver, and we,re going into a corner, I brace myself and my mind says "We'll never make it!!!!!", but we always do! And then the lap time is slower than mine! So my perception is HUGELY different in the right seat.

It is also amazing how many levels of grip there are...track, tires, car set up, etc. It makes a big diff. Just look at Winston Cup!

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Jake Gulick
ITA 57 RX-7
New England Region
[email protected]