Track Tuning vs. Table Top Tuning

[Sappington R]

Had a little to much time lately and also in preparation for the next pwdr in Apple Valley MN, Proxy Race this coming weekend: I made some very interesting observations that I wanted to share with fellow pineheads about track tuning canted axles.

The set-up was a 4 1/2"WB Limited on full weight BSA- 3 wheel. I used the RR tool for 2.5% on the Rear and 2.5% on the FDW.

My normal tuning process is to set-up on the Granite counter top and roll 5-6'. Always looking for perfect alignment on the rears first (discovered that using an RS wheel on the FDW with Straight axle makes tuning the rears easier) then switch to the bent FD wheel axle/combo.

In an ideal situation you would have a car that rolls forward and back with no migration to the body of the RW- right? Then... a little pos. camber on the FDW tune it to RR 1"over 5-6'should be ideal...

Having used the new PBJ and RR tool- I found that table top tuning and track tuning revealed some major differences.

When the rear alignment was "perfect" on the table top- I had a huge amount of rear wobble on the track (32' piantedosi aluminum). I spent several hours "tweeking" and took a limited running a 2.500 to 2.473 (by the way the track record for a stocker is 2.440, best single run was 2.436).

Here's the deal: After table tuning and observing rear end wobble at speed, I began making small adjustments on the bent axles on the rear- both left and right. I found some interesting interactions between the L FDW and the R RW. For example: Toe-in slightly on the rear then adjust the FDW steer in or out with POS Camber- changed everything- I took it back to the table and it looked terrible- but performed at record & consistent speed on the track.

OK- so I'm sending it in this week... "Giant Steps" is the car name in limited. Don't know if it will be in the same realm as Wasabi but "I did my best"

I'm starting to re-think the entire tuning process.


Any thoughts???

[Sappington R]

Ichiban,
Yes, I did narrow the FD side about 1/16". It was one of the first tips that I got when I found this message board.

The positive camber on the FDW vs. negative on the rear is a tip that I picked up from some of the "Bluegrass" builders that finished at the top in all classes. I was a non-believer until I saw it first hand. I believe that the theory and advantage is that less of the wheel will contact the center rail (one point vs. two points on a neg. camb. FDW) make sense? However, on a full weight BSA wheel it will really make a lot of noise compared to a neg. camb. FDW.

The point that I was trying to make is that= you think you may have great alignment on a tuning board, but can get much improvement by tuning the rears on the track (besides the obvious FDW). I think that there is an interesting interaction between the FDW and the Rear NDW- in other words toe in or out on one effects the other- it definitely changes the amount of steer. But, overall, I think you can get your cars faster this way.

[slkrnsntracing]

I think it is obvious that any equipment that a racer has can help them get their cars faster whether it be a test track, cnc lathe, or whatever.

I would like the new guys thinking about getting started Proxy Racing to understand that is not necessary to have these items to be competitive, learn how to build a faster car, or have fun and meet a lot of great guys. Example; Steve/Proquest.

I know that there are a lot of guys who run fast that have test tracks, but I think most of them would be very competitive even if they didn't have one.

I personally feel that spending a few hours at a live race is also a very good way to learn. I know that I have been to 4 live races, and have discovered a lot of valuable tricks at each of them.

Just my $0.02 worth.

Phil

[slkrnsntracing]

Dec 3, 2008 18:14:10 GMT -6 ichiban said:

Dec 3, 2008 16:01:27 GMT -6 slkrnsntracing said:

ichiban,

I think it is obvious that any equipment that a racer has can help them get their cars faster whether it be a test track, cnc lathe, or whatever.

I would like the new guys thinking about getting started Proxy Racing to understand that is not necessary to have these items to be competitive, learn how to build a faster car, or have fun and meet a lot of great guys. Example; Steve/Proquest.

I know that there are a lot of guys who run fast that have test tracks, but I think most of them would be very competitive even if they didn't have one.

I personally feel that spending a few hours at a live race is also a very good way to learn. I know that I have been to 4 live races, and have discovered a lot of valuable tricks at each of them.

Just my $0.02 worth.

Phil

I think you meant Sappington R, he started the thread.

Sorry ichiban,

I realize I put your name at top, but the message was actually meant for the new guys who are thinking about racing that are worried that they can't be competitive if they don't have a test track.

Sorry if I didn't explain myself very well. I certainly wasn't trying to put anyone down that has a track.

Phil

[roosclan]

Tons of questions, so bear with me:

Dec 2, 2008 21:01:58 GMT -6 Sappington R said:

The set-up was a 4 1/2"WB Limited on full weight BSA- 3 wheel. I used the RR tool for 2.5% on the Rear and 2.5% on the FDW.

Any particular reason you chose the same degree of bend on front and rear instead of 1.5 on the front?

When the rear alignment was "perfect" on the table top- I had a huge amount of rear wobble on the track (32' piantedosi aluminum). I spent several hours "tweeking" and took a limited running a 2.500 to 2.473 (by the way the track record for a stocker is 2.440, best single run was 2.436).

By rear wobble, do you mean fishtailing, or wheels wobbling on the axles?

Here's the deal: After table tuning and observing rear end wobble at speed, I began making small adjustments on the bent axles on the rear- both left and right. I found some interesting interactions between the L FDW and the R RW. For example: Toe-in slightly on the rear then adjust the FDW steer in or out with POS Camber- changed everything- I took it back to the table and it looked terrible- but performed at record & consistent speed on the track.

1) Toe-in on the rear = twisting the axles toward the front of the car, right?
2) FDW having positive camber will cause it to ride on the car body, won't it?
3) if it rides on the car body, how does it RR?

[Sappington R]

Roosclan, great questions you ask & I'll be happy to reply to all. But first I have one for you: I've never been able to figure out how to "box" an excerpt from a previous message when posting a reply, can you help me?

Your questions:

!. Why did I use 2.5 on the front instead of the 1.5? Two reasons- One: when observing the FDW on a flat surface standing still I was looking to see a little bit of daylight between the inner edge of the wheel and the outer edge- wanted the inner edge slightly off the ground- the extra 1 degree did the trick. I don't know if it's ever been proven how much cant is the ideal amount on the front, but will tell you this: (which is the second part of my answer) Two: I personally saw the winning cars at The bluegrass and they appeared to have even more than 2.5 on positive camber on the front- so I was really just trying to do what looked to be a proven method. With that said, I think the real test would be to test multiple set-ups and see what is optimal- my hunch is that wheel base and COM will also play a role in optimization.

2. Wobbling or Fishtailing? Yea, it was actually a little bit of each. the small adjustments made the car run as smooth as I've seen. Regarding the wheel wobble: Again, it looked fine on the granite counter top- no wobble on a simple roll test- it was the high speed that magnified the problem.

3. Toe-in? Yes, turning very slightly forward which would be counter clockwise on the left and clockwise on the Right.

4. Positive Camber will cause it to ride to the body? Yes it does cause that on a test surface. But that problem is overcome by making contact with the rail- it pushes it back out, and again, I think that weight placement & wheel base play a part. It will always RR as long as you have the stear adjusted so- The trick I believe is to keep the rear wheels off the rail and also away from the car body.

I have to tell you though, I was a NON-BELIEVER in Pos Camber on the FDW until I tried this.

Roosclan, do you proxy race?

[ichiban]

Dec 5, 2008 8:31:40 GMT -6 Sappington R said:

Roosclan, great questions you ask & I'll be happy to reply to all. But first I have one for you: I've never been able to figure out how to "box" an excerpt from a previous message when posting a reply, can you help me?

Sappington R,
1) Select the quote button next to the previous message you want to "box". This will automatically "box" the entire message.
2) To break up the previous message, insert a "[/quote]" at the end of the part you want to box. You can then enter your comments and remove the rest of the previous message that you dont want to quote.
3) To quote the rest of the message, you can copy and paste the initial header of the previous quote which is something like, "

Dec 5, 2008 8:31:40 GMT -6 Sappington R said:

" or you can simply type "[ quote ]" minus the spaces as I've done here.

Your questions:

!. Why did I use 2.5 on the front instead of the 1.5? Two reasons- One: when observing the FDW on a flat surface standing still I was looking to see a little bit of daylight between the inner edge of the wheel and the outer edge- wanted the inner edge slightly off the ground- the extra 1 degree did the trick. I don't know if it's ever been proven how much cant is the ideal amount on the front, but will tell you this: (which is the second part of my answer) Two: I personally saw the winning cars at The bluegrass and they appeared to have even more than 2.5 on positive camber on the front- so I was really just trying to do what looked to be a proven method. With that said, I think the real test would be to test multiple set-ups and see what is optimal- my hunch is that wheel base and COM will also play a role in optimization.

2. Wobbling or Fishtailing? Yea, it was actually a little bit of each. the small adjustments made the car run as smooth as I've seen. Regarding the wheel wobble: Again, it looked fine on the granite counter top- no wobble on a simple roll test- it was the high speed that magnified the problem.

3. Toe-in? Yes, turning very slightly forward which would be counter clockwise on the left and clockwise on the Right.

4. Positive Camber will cause it to ride to the body? Yes it does cause that on a test surface. But that problem is overcome by making contact with the rail- it pushes it back out, and again, I think that weight placement & wheel base play a part. It will always RR as long as you have the stear adjusted so- The trick I believe is to keep the rear wheels off the rail and also away from the car body.

I have to tell you though, I was a NON-BELIEVER in Pos Camber on the FDW until I tried this.

Roosclan, do you proxy race?

Use the preview button to check what your message will look like before posting.

[roosclan]

Dec 5, 2008 8:31:40 GMT -6 Sappington R said:

Roosclan, great questions you ask & I'll be happy to reply to all. But first I have one for you: I've never been able to figure out how to "box" an excerpt from a previous message when posting a reply, can you help me?

ichiban got it.

!. Why did I use 2.5 on the front instead of the 1.5? Two reasons- One: when observing the FDW on a flat surface standing still I was looking to see a little bit of daylight between the inner edge of the wheel and the outer edge- wanted the inner edge slightly off the ground- the extra 1 degree did the trick. I don't know if it's ever been proven how much cant is the ideal amount on the front, but will tell you this: (which is the second part of my answer) Two: I personally saw the winning cars at The bluegrass and they appeared to have even more than 2.5 on positive camber on the front- so I was really just trying to do what looked to be a proven method. With that said, I think the real test would be to test multiple set-ups and see what is optimal- my hunch is that wheel base and COM will also play a role in optimization.

The boys will be racing on a Best Track (42', I think) with a 3/4" to 7/8" COM, and they're stuck with the stock wheel base, so should we go for the 1.5 or the 2.5 bend on the FDW?

2. Wobbling or Fishtailing? Yea, it was actually a little bit of each. the small adjustments made the car run as smooth as I've seen. Regarding the wheel wobble: Again, it looked fine on the granite counter top- no wobble on a simple roll test- it was the high speed that magnified the problem.

Well, all I have is a test board I picked up at Home Depot, so we'll see how things look on there. I just might experiment with one for myself and test it at the pack's Test & Tune night (on their old wood track) to see how the positive vs. negative camber affects it.

4. Positive Camber will cause it to ride to the body? Yes it does cause that on a test surface. But that problem is overcome by making contact with the rail- it pushes it back out, and again, I think that weight placement & wheel base play a part. It will always RR as long as you have the stear adjusted so- The trick I believe is to keep the rear wheels off the rail and also away from the car body.

I have to tell you though, I was a NON-BELIEVER in Pos Camber on the FDW until I tried this.

I should have figured that the force of the rail would push it back out. I wonder if it would be worth it to put EZ-Slide graphite paint on the body where the wheel hub would touch. It dries to a solid graphite.

Roosclan, do you proxy race?

I don't, actually. I have 3 cub scouts who need to build cars this year, and then I might have time to make one for myself to enter. I've been thinking about it for either Rookie or Pure Stock class.