Suggestions on why is my handling fading?

[musolino21]

I have a good base setup and have a competitive car for the first half of the race. We ran Penna. Motor Speedway last night, 8/9/14... PPMS stays fairly consistent throughout the duration of the race, the track will slow down, but not like many other race tracks.

I usually have a consistent car the whole night with great tire wear and temperatures, but I am puzzled that my car began a four wheel slide last night in the feature.

1.) My tires (1600's Hoosier track rule) were not brand new, but they did not have a full race on them prior to last night. Is it because of heat cycles?

2.) Fuel burn off usually doesn't affect my car. I scale at 15 gallons at 55% Rear. I start the feature with 18 or 19 gallons and on the scales that puts me about 55.2% or 55.3% with very little wedge loss and no change to the Left Side percentage. Am I missing something with burn off?

3.) Is there anything else that I am missing that will cause my handling to fade?

*** Also, I am not looking to change spring combinations or drastic setup changes.

Our team does very well... for the 2014 Firecracker at Lernerville on night one we qualified 13th out of 56 entries and night two qualified 20th out of 56 entries and no the track wasn't tacked up. Until the heats were muddy and we don't have 900 hp. lol.

We are a solid top ten and top five car. We run a 2009 Rocket Blue/Grey and a 10 year old 421 Malcuit, everything is in good working condition and maintained very well.

Any suggestions is much appreciated, thanks.

[Garrettshurling]

Shocks come to mind.
1. Inadequate gas pressure- If your running mono tube gas shock and don't have enough pressure in them, the oil will be allowed to cavetate or bubble like a soda can when the pressure is released. This hurts the shocks ability to control the rebound and compression loads.

2. Hydraulic shocks being overloaded- If your on a rough or "washboard" race track, the same thing as above can be happening to a hydraulic shock because they aren't suited for bumpy tracks.

Is the car staying neutral when the handling deteriorates?

[musolino21]

The car did develop a loose condition, not extreme though.

I am still learning about the shocks. They are used Integra mono-tube canister we purchased this year, they are about three years since new. All shocks have been rebuilt earlier this year and are in good working order. Before the feature I did increase compression on the LF, its a common adjustment I use to prevent a loose condition on entry. It did help, and to be more specific, the car was great on entry, but would four wheel slide on and off the gas when I got to the center and off... with a developing loose condition.

In the heat race I had gas pressures of 50psi on left side, 40psi on right side. For the feature I reduced pressures on the right side to 35psi.

[Garrettshurling]

I'm not sure if those shocks can handle that low pressure, especially if you have a lot of rebound or compression control on them. Typically, the more dampening force you ask out of the shock, the more pressure it need to keep the oil inside from cavetating. I don't have any info on Integra mono tube shocks, but I'ld contact them and ask them what the minimum gas pressure you should run for your specific valving.

What your describing sounds pretty consistent with classic shock fade. I hope that helps man!

[musolino21]

Your input is helpful, previously this year I did keep the pressures at 50 all the way around. Low pressures would seem to relate and your explanation of the shocks makes sense. Thank you Garrett.

[Garrettshurling]

Your welcome man. Let me know if that fixes it!