Teching Ride Heights

[hray]

Actually the BB/SS cars do "settle" somewhat in a race. The shocks are digressively valved so they have practically no compression resistance at slow velocities. The LMS/ASA car Jason is running will push down to the bump stops just from the downforce in the straight-a-way. When he goes into the turn, the rear end raises up from braking to put the spoiler higher, and as he accellerates off the turn the rear squats and the nose raises about 3 inches (held down by the shocks) until aero downforce pushes it back on the bump stops.

I think a couple of you hit it right. As the shock heats up from excessive movement, they have less resistance to compression at slow velocities (remember, they are digressively valved, so they reach peak compression resistance rather quickly as velocity increases, minimizing the effect of heat). When the car comes off the track, any extra amount of weight on the car (a crew member pushing it to tech, running over a bump in the pit paving.....) causes the car to "settle" anf the hold down nature of the shocks won't let it come back up.

Next time you are at the track, walk over to a BB/SS car and (with the owners permission) push the nose of the car down 2 or 3 inches, then just step back and count how long it takes the bumper to come back to original height.

I don't know the answer, but you can't set a BB/SS car at 5 inches just so it will tech at 4 inches after the race. We simply have the crew members that are pushing the car to the tech pad make a final pull up on the car before they turn it loose. It's funny, because so many teams were doing that, the rules were changed to read "teams are allowed to pull up on the front and rear bumpers 1 time before ride height is checked".

[NickHolt]

Rusty, which is exactly why I suggest that those classes that have bodies that enable them to keep the air out from under the car (or truck) and that typically utilize BB/ss setups, really don't need a ride height rule in the first place.

 

On a side note, there is a trend in some areas of the country where teams are backing off the BB/ss setups to a degree. I'm not going to go into detail here, but some teams that were having tire management issues with the the full BB/ss setups (those that utilize the huge RR springs) are backing off and actually not running on the bump stops on the right side any longer. But once again, no ride height rule is needed because they are competing with cars using the full BB/ss setups that are nearly on the ground.

 

However, in those classes that typically do not have downforce bodies, including the modifieds, a right height rule is essential to keep one of the key factors in the weight transfer equation controlled to some extent.

 

Nick

[Banker36]

Chase,

 

Its been awhile since Ive watched anyone get teched but from reading your post your telling me that he rolls the ride heigth checker under the nose now? I cant ever remember that being the case. Maybe I read that wrong.

Edited September 19, 2008 by ss36_tams37

[Crazyhorse]

he does it....he did it to yours matt when we asked him to check it before we scaled.

[Truck99]

Chase,

 

Its been awhile since Ive watched anyone get teched but from reading your post your telling me that he rolls the ride heigth checker under the nose now? I cant ever remember that being the case. Maybe I read that wrong.

 

Yes sir, like Crazyhorse said. The nose has to clear also.

[hray]

Nick,

You are right and actually one of the ones I was referring to that has it right (which we would all expect). As far as teams backing off the BB/ss setup, we see a definite shift away from those setups on high banked tracks. In the NASCAR LMS series in western PA and eastern OH many of the tracks are medium to low banked 1/2 mile tracks that lend themselves to BB/ss. Motordrome and Jennerstown for instance are 1/2 mile with sweeping turns and 9* banking in the turns and 6* banking in the straight-a-way. They run heat races of 20 laps and features are only 50 laps, so tire wear is not much of a problem. Jason's setup was done with the help of Lensing at Lefthander and I won't say what the actual spring rates are, but as I said in the above post, the front end will push down to the bump stops with downforce on the straight-a-way. The right rear spring is almost 3 X more that the front springs so I doubt the right side tires would make a 150 lapper.

[Banker36]

he does it....he did it to yours matt when we asked him to check it before we scaled.

 

Wow, I never noticed that. How in the hell does it pass with the valance on the front? Well, guess it doesnt really matter if we passed.

 

But I do like the fact that the headers dont count and that there is a clear distinction that they dont cause mine hit.

Edited September 20, 2008 by ss36_tams37

[mikeg]

I have some of these ride height wheel type checkers available if anyone needs a set.

[speed demon 7]

he does it....he did it to yours matt when we asked him to check it before we scaled.

 

Wow, I never noticed that. How in the hell does it pass with the valance on the front? Well, guess it doesnt really matter if we passed.

 

But I do like the fact that the headers dont count and that there is a clear distinction that they dont cause mine hit.

 

 

I am not trying to start an arguement, but how is there a clear distinction that the headers and crossmembers don't count. If you are a new driver reading the rules and going by the rules, they say nothing about headers, [edited out by Nick Holt, 9/25/08]

 

18. RIDE HEIGHT:

a. A 4 1/2-inch minimum ride height must be maintained at all times:

i. Measured from the lowest point on the frame to the ground.

ii. Any obstruction, at any point under the car, below the 4 1/2” minimum

height is considered too low.

iii. Regardless of what part of the car is obstructing the 4 1/2” wheel.

1. The only exemption is if deemed by the technical inspector that

race damage from the same night is the cause of the infraction.

iv. The ride height is measured with the driver out of the vehicle.

 

this is the ruling off of the THR website for Super Stocks.

Edited September 25, 2008 by NickHolt

[NickHolt]

From the original post in this thread

 

NOTE: This is not intended to be a bitch session, but rather a discussion that may produce some valuable results for those tracks that are interested in such things. Be warned ahead of time - complaints and recounting of sorrowful tales of being DQ'd unjustly, etc. will be removed.

 

Arthur,

 

I'm sorry, but this discussion is not intended to be a re-hash of complaints which anyone might have. I am leaving portions your post up because it does bring up the general issue that there will always be rules that may need to be updated over the winter.

 

So, please, let's keep this discussion headed in a positive direction.

 

Thanks.

[RodneyRodriguez]

one thing this thread did for sure, there were many (including #7 SS!) using jack's wheel before the races in the garage Saturday!

[bigfat]

Does checking the Ride Hieght w/ the driver out of the car give an advantage to us BIGFAT drivers?

[NickHolt]

I had hoped that this thread would not degenerate into the same old bitch session, but alas...

 

I have deleted several of the recent posts that dealt with a specific incident that has been hashed and re-hashed several times in other threads. I have also deleted some posts that responded to posts describing that situation.

 

Thread closed.

 

Nick