Still battling with the car. I'm yet to make a complete pass. I went to a test and tune and and changed the shock settings dramatically and COULD NOT get the car to the 60'. Strangely though, the car was sticking when I let go of the TB and would knock the tires off (QTP's) .5-.7 seconds after I launched. The following Sunday, 6/16, went to a no prep event and lost in the 1st round but made 4 more test hits. This time I had a couple of friends there that took a bunch of videos. It only took me two days of watching the vids and looking at datalogs to figure it out - I'm topping out the rear shocks which immediately unloads the rear tires. So back to the drawing board lol.
One of the changes prior to this outing was changing the rear shock settings. I previously ran heavy rebound and light compression - 15-17 rebound and 6-9 compression with the radials. Those are from full loose and 18 settings available. But during these runs I was 6-9 on rebound and 15-16 on compression. Since I've determined that I'm over extending the rear shocks, obviously I have to slow down the the extension (rebound), so I'll be cranking up the rebound a bunch.
Another thing that we put into the tune was a delay in the launch retard. The reason for it is the bias ply tires need wheel speed to be effective, from my understanding this is a common practice that I was unfamiliar with - we were not having any launch retard for .2-.3 seconds. I've always been radial racing where the tire needs to dead hook with no spin - it's a different mentality and strategy. As I mentioned previously, the car was hooking when doing this, I was actually pulling both front tires immediately and once they stop coming up the rear separates in a short instance and tops out the rear shocks. I tried extending the amount of time to start the retard and that accomplished absolutely nothing other crushing the rear tire.
This weeks changes : I located the rear shock up 1.125" to allow for more another 1" of separation before topping out the shock; and I added 1" taller upper ball joints (I don't know if these will help my launching issue, but they definitely are helping the bump steer.) And the next outing I'm going to crank up the rebound. It will probably take a couple of hits to figure out if a shock setting change is all that is needed. If shock settings can't get it done, then I'm going to have to move the rear bars to either increase my instant center length and/or drop my antisquat percentage.
I've done a lot of thinking, probably too much, about what has caused this with virtually the same rear setup I had previously. The only thing that I've come up with is the different tire and 200+lbs off the front end is loading the chassis differently. Obvious to me, the car should be faster with the weight change alone, but this is getting a little frustrating, but I guess if it were easy, then everyone would be doing it lol.
Almost forgot to mention, I lowered the front of the car over the winter with an idea to increase front end travel. I'm going to raise it back up to approximately where it was previously and I'm going to limit front end travel. I don't think this is much of an issue at this moment, but adjusting front end travel is a quick and easy adjustment at the track with the front end limiters.
Stay tuned for how to make your car slower haha.
One of the changes prior to this outing was changing the rear shock settings. I previously ran heavy rebound and light compression - 15-17 rebound and 6-9 compression with the radials. Those are from full loose and 18 settings available. But during these runs I was 6-9 on rebound and 15-16 on compression. Since I've determined that I'm over extending the rear shocks, obviously I have to slow down the the extension (rebound), so I'll be cranking up the rebound a bunch.
Another thing that we put into the tune was a delay in the launch retard. The reason for it is the bias ply tires need wheel speed to be effective, from my understanding this is a common practice that I was unfamiliar with - we were not having any launch retard for .2-.3 seconds. I've always been radial racing where the tire needs to dead hook with no spin - it's a different mentality and strategy. As I mentioned previously, the car was hooking when doing this, I was actually pulling both front tires immediately and once they stop coming up the rear separates in a short instance and tops out the rear shocks. I tried extending the amount of time to start the retard and that accomplished absolutely nothing other crushing the rear tire.
This weeks changes : I located the rear shock up 1.125" to allow for more another 1" of separation before topping out the shock; and I added 1" taller upper ball joints (I don't know if these will help my launching issue, but they definitely are helping the bump steer.) And the next outing I'm going to crank up the rebound. It will probably take a couple of hits to figure out if a shock setting change is all that is needed. If shock settings can't get it done, then I'm going to have to move the rear bars to either increase my instant center length and/or drop my antisquat percentage.
I've done a lot of thinking, probably too much, about what has caused this with virtually the same rear setup I had previously. The only thing that I've come up with is the different tire and 200+lbs off the front end is loading the chassis differently. Obvious to me, the car should be faster with the weight change alone, but this is getting a little frustrating, but I guess if it were easy, then everyone would be doing it lol.
Almost forgot to mention, I lowered the front of the car over the winter with an idea to increase front end travel. I'm going to raise it back up to approximately where it was previously and I'm going to limit front end travel. I don't think this is much of an issue at this moment, but adjusting front end travel is a quick and easy adjustment at the track with the front end limiters.
Stay tuned for how to make your car slower haha.
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