Suspension Travel

[Count]

Just doing some preliminary research here.  I'm trying to determine ride height (85 corvette) and am wondering what is recommended for suspension travel.  Does anybody out there travel the suspension?  Or are you using bump stops, coil bind, that sort of thing and basically running solid on the frame?  Also what frame heights are you running on your cars?

Thanks for the help,
Count

[Sumner]

Just doing some preliminary research here.  I'm trying to determine ride height (85 corvette) and am wondering what is recommended for suspension travel.  Does anybody out there travel the suspension?  Or are you using bump stops, coil bind, that sort of thing and basically running solid on the frame?  Also what frame heights are you running on your cars?

Thanks for the help,
Count

We are trying to keep about 1 1/2 inches of travel in Hooley's Stude.  We have stops (I think there are pictures in the build section on it).  One thing to keep in mind is adding weight and how you are going to compensate for that.  We've gone from 3000 lbs to a little over 4000 lbs. and hope to have another 500-800 with us this summer.  So if you set your ride height up for one weight and find you need to add weight you will now maybe find you are on the stops.  This happen to us the year the course was so bad (2005).  By the time we got that taken care of the blower seal let go and we were done.  Probably a good thing that year.  Anyway try and make the suspension adjustable in some way.

I'm going for about 1 1/2 inches of travel on my lakester and have the suspension setup in such a way that with one set of springs I can change the leverage on the springs and keep the ride height the same with jack screws.  I'll also be able to have quite a bit of control over the shock travel, there again using different leverage, and in effect be able to change the shock action (how far it travels with 1 1/2 inches of wheel travel).

A couple reasons for the stops is to prevent not only bottoming out, but to make sure your fenders and such are not getting into your tires when there is a lot of down-force on the front of the car.  That down-force on a high speed car can also take the travel out of the suspension, especially the front.

Good luck,

Sum

[Jonny Hotnuts]

http://www.landracing.com/forum/index.php/topic,3308.msg47234.html#msg47234
http://www.landracing.com/forum/index.php/topic,2422.0.html

There is a good bit of reading here but you may find it interesting about vette setups.

-JH

[Count]

Thanks Sumner and Johnny,

Now ya've got me thinkin' a little more and ya all might have some insights into other aspects of my set up. 
I've picked up some lsr tires from a friend 24's up front and 26's for the rear.  I have a few options for the rear suspension.  I have a couple of ford 9in. housings in the garage. One is set up for truck arm suspension, and the other is a three link set up from a late model, or I could redo the brackets and run a four link set up.  For up front I'm leaning towards coilovers and being done with it. (especially after reading about the transverse springs breaking at speed.)  Any thoughts on the total package, what I'm missing, need to get etc.etc.etc. 
I'm open to any suggestions, so please, if you have anything, even if it seems insignificant, let me know.  The little details can be the difference between achieving your goals and going home victorious, or just going home.

[Sumner]

Thanks Sumner and Johnny,

Now ya've got me thinkin' a little more and ya all might have some insights into other aspects of my set up. 
I've picked up some lsr tires from a friend 24's up front and 26's for the rear.  I have a few options for the rear suspension.  I have a couple of ford 9in. housings in the garage. One is set up for truck arm suspension, and the other is a three link set up from a late model, or I could redo the brackets and run a four link set up.  For up front I'm leaning towards coilovers and being done with it. (especially after reading about the transverse springs breaking at speed.)  Any thoughts on the total package, what I'm missing, need to get etc.etc.etc. 
I'm open to any suggestions, so please, if you have anything, even if it seems insignificant, let me know.  The little details can be the difference between achieving your goals and going home victorious, or just going home.

I like the truck arms and wish I would have put them on my truck.  With NASCAR using them there would be ton of springs to pick from probably and with the screws easy to set ride height.  I think they would be excellent.

For the front the coil-overs might not be the easy problem solvers they first seem.  You can only adjust the ride height so far and not as much as one would think.  Don't forget how much the car might end up weighing so make sure you get ones that have some pretty heavy spring options available.  That was a problem we had.  Still saying that they are probably your best bet if they will work in your application.

c ya,

Sum

[Seldom Seen Slim]

Count -- you're screwing up my calculations of the median age of people on this forum.  Last time I figured it was about 58, but you're changing things and the new median age is going to be way higher.  Is there something you want to tell us -- some secret about how you're still able to walk and chew gum and think, all at the same time - at your age?

[Count]

Well Slim, I owe it all to clean living.






Actually in real life I'm 39 years old.  Guess maybe I ought to fix that.

[Stan Back]

Fixin' being 39 will take care of itself in less than a year from now . . .

[ddahlgren]

Personally I would be very careful about having as much as 1.5 inches of travel as a heavy car with soft spings can be quite a handful. Picture autocrossing a 63 Caddy if you think I am wrong on that. Granted we are not autocrossing if nothing goes wrong but if it does you are. In 2005 when everyone said the track was usless ran over 260 mph in a 2600 lb car and it was just fine no issues at all with 3/8 of travel. Traction is designed in from the start with the aero package and suspension pick up points. If you have to add tons of ballast you have picked poorly from the start and applying a band aid at the track. The cheapest thing someone can do and always saves it for last is to spend the grand it takes in a wind tunnel and see if the car is worth the effort from the start. If there are inherent problems with the shape of the body causing execessive drag or lift you probably can not make it significantly better and stay within a lot of the rules for many classes. Sometimes it is better to cut your losses and jsut pick a different body to start with as they all cost about the same to prep and saving a couple of grand because you have a car out back or even worse because it is a favorite brand is another way to spend money and have a lack of success. On the Corvette might want to send Ed VanScoy an e-mail and see what he did or thinks as he has raced a few of them over the years..
Dave

[Count]

Thanks Dave,
Good points to consider.  So It sounds like people are traveling their cars from between .5 to 1.5 inches.  Also I would think the suspension needs to be set up for some pretty heavy spring rates.  Anybody have any other ideas on this?  How about ride height?  How far from the ground are ya all setting things up?


Yeah, Stan Back, be 40 in about a month.  Can't seem to avoid this one.

[Glen]

Well kids I guess I'm 504 in dog years.

[bvillercr]

Our car is pretty low.  Just behind the headers our car sits about two inches above the ground.

[Rick Byrnes]

Well kids I guess I'm 504 in dog years.

Yeah Barrett, and thats ooooollllllddddd.

:-d

[jackson]

We've been running with the no suspension for a few years and it has been exciting sometimes when the track is wet and it is windy.  When the track is dry and the wind is reasonable, it is like sitting in a recliner playing a video game.  If salt conditions make a permanent change for the worse, we will likely start adding some suspension.  But, if the track continues to just be so dependent on what the weather has been like for the preceding months, we may just watch gas prices and the track condition report, and decide if we want to participate that year. The cancellation fee is far cheaper than the required fuel to get there.

[RidgeRunner]

     For Maxton minimum ride height of 2 to 2 1/2 inches might be numbers to think about.  Improvements are always being made but taxi way and road down to staging can still have rough spots at times.  Couple of cars I have been involved with have run that low with no problems yet.  Not sure on the on the amount of travel they experienced so can't offer anything on that.

                           Ed Purinton