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Pappy
10-27-2016, 02:06 PM
I went to Inde with Arizona Vipers yesterday and the following is what I learned:

Trailer: I used my 8 foot-wide trailer (78 inches between fenders) which only gave me 1 inch of clearance trailer fender-to-rocker. I used safety chain S hooks inserted in the rear angle iron jack points and cross-strapped the rear from there to prevent side-to-side movement. Then I ran a pull down strap through the square access hole to the rear frame to prevent up and down movement. Worked like a champ - 450 miles of towing, some on rough secondary asphalt with no damage. I had the splitter and strake extensions on, used 131 inch Race Ramps for loading, but had to raise the ride height .5 due to some trailer clearance issues that I will clean up later. I also used a six foot sling strap (nylon) through the Woodhouse tow ring to attach the winch. Worked great and no damage to the finish of the ring.

Suspension: I wanted to establish a good baseline in a controlled environment (day long private session arranged by Arizona Vipers). I started with 2.5 degrees of camber, 6 degrees of caster, and the recommended default shock settings. Rake was correct, but ride height was .5 inch high front and rear. I started stock Kuhmo tire pressures at 29 lbs cold and kept them bled to 33 lbs hot. On easy shake-down laps the front tires had significantly higher temps on the inside. However, the harder I pushed the car, the more even the temps became across the tire. I added a bunch of rebound to the front shocks (7, then 8). Here is my take-away. Handling was best when I drove hard with very late/very aggressive braking followed by turn-in immediately after braking. Tire temps were almost dead even across the tire and about 10-15 degrees cooler than the peak temps I was getting on the inside edges during the shake-down laps. I had about 60 minutes total of track time at speed, and the tires look great. No appreciable difference in the tire wear inside versus outside, although the outside .5 inch of each tire did not get much use. Not to imply that the tires did not wear, just that the wear was pretty uniform. The rears looked no worse for wear.

Take my inputs for what they are worth - just one man's opinion. I still believe that forcing and/or pinning the nose down at corner entry through the apex to take advantage of any caster gain is important to having good dynamic camber geometry.

Pappy

allans
10-27-2016, 09:03 PM
Thanks Pappy, Further support for 2.5 camber front which is what i'm running with similar results. Best, Allan

jpgunn123
10-27-2016, 10:45 PM
Agree -- Kumhos are best at -2.5 front with plenty of caster.

jpgunn123
11-09-2016, 12:41 AM
I ended up at 7 on rebound at Buttonwillow. The harder you run, the more the tires heat up the outside.

I am at -2.8 and tire wear looks really good.

jpgunn123
11-09-2016, 12:42 AM
I ended up at 7 on rebound at Buttonwillow. The harder you run, the more the tires heat up the outside.

I am at -2.8 on Hoosier R7s and tire wear looks really good.

Arizona Vipers
11-09-2016, 11:36 AM
I ended up at 7 on rebound at Buttonwillow. The harder you run, the more the tires heat up the outside.

I am at -2.8 on Hoosier R7s and tire wear looks really good.

7 in the front? Why was it pushing? Did you lower the compression?
Increasing the rebound and dropping the compression in the front and doing the opposite in the back greatly reduced my understeer, but I still had a lot with the wing set at 2. I changed it to 1, will see if it helps.

jpgunn123
11-09-2016, 04:21 PM
The car was not pushing, but the response was slow in the front through the Esses and the tight stuff. Also, running more rebound helps suck the nose down if you set it with some firm braking and are smooth off the pedal. I left Compression at 7.

stradman
12-04-2016, 02:20 PM
I went to Inde with Arizona Vipers yesterday and the following is what I learned:

Trailer: I used my 8 foot-wide trailer (78 inches between fenders) which only gave me 1 inch of clearance trailer fender-to-rocker. I used safety chain S hooks inserted in the rear angle iron jack points and cross-strapped the rear from there to prevent side-to-side movement. Then I ran a pull down strap through the square access hole to the rear frame to prevent up and down movement. Worked like a champ - 450 miles of towing, some on rough secondary asphalt with no damage. I had the splitter and strake extensions on, used 131 inch Race Ramps for loading, but had to raise the ride height .5 due to some trailer clearance issues that I will clean up later. I also used a six foot sling strap (nylon) through the Woodhouse tow ring to attach the winch. Worked great and no damage to the finish of the ring.

Suspension: I wanted to establish a good baseline in a controlled environment (day long private session arranged by Arizona Vipers). I started with 2.5 degrees of camber, 6 degrees of caster, and the recommended default shock settings. Rake was correct, but ride height was .5 inch high front and rear. I started stock Kuhmo tire pressures at 29 lbs cold and kept them bled to 33 lbs hot. On easy shake-down laps the front tires had significantly higher temps on the inside. However, the harder I pushed the car, the more even the temps became across the tire. I added a bunch of rebound to the front shocks (7, then 8). Here is my take-away. Handling was best when I drove hard with very late/very aggressive braking followed by turn-in immediately after braking. Tire temps were almost dead even across the tire and about 10-15 degrees cooler than the peak temps I was getting on the inside edges during the shake-down laps. I had about 60 minutes total of track time at speed, and the tires look great. No appreciable difference in the tire wear inside versus outside, although the outside .5 inch of each tire did not get much use. Not to imply that the tires did not wear, just that the wear was pretty uniform. The rears looked no worse for wear.

Take my inputs for what they are worth - just one man's opinion. I still believe that forcing and/or pinning the nose down at corner entry through the apex to take advantage of any caster gain is important to having good dynamic camber geometry.

Pappy

Hi Pappy
Great write up and insight! I can't wait to get mine on the track soon. Can I ask are you running stock CCB's? How are those holding up?

stradman
12-04-2016, 02:21 PM
Sorry also you say you're running 0.5 inch ride height. I'm sorry if I'm sounding ignorant but does this mean you are running 0.5 inches lower than street??