Track temp. and 60' times?
 

I have great 60's when the sun is beating on the track, 1.360 - 1.368. It will carry the front wheels 10-20'. When the sun goes down my 60's fall to 1.38's and pops the front up and falls back down. Makes it hard to run on the 10.00 index. I even notice if we get extended cloud cover the same happens. Dam car hooks better on 90 deg. sunny days than on cool nights.
Is there more bite on a cool track? I am think of tightening the rebound some and leaving the comp. the same, so it doesn't hit the tires as hard.
Do others have this problem? Changing shock setting for different conditions?

Stock a-body suspension and stock locations. Double adjustable shocks in the back and stock regular shocks in the front. Leave on the trans brake at 3800.

My 1st thoughts were the traction is better?
But your car is setup for the looser condition.

May try leaving at a higher RPM when cloudy/cold and see if it comes out harder?

Then probably have to adjust for the track.

:confused:

What's your MO, burn out dry hop and then stage?
Many people do a dry hop after the burn out and that just uses up your burn out by leaving your needed sticky rubber way behind the starting line!
If you do not do a dry hop then at cooler track temps start your burn out as your competitor Pulls up to stage.
If your doing longer burnouts at cooler times that can even be a issue with some slicks especially when you get into second round action or so and your basically pulling right back up into the staging lanes.
At times like that with most slicks you only need to spin then up until you start to see smoke , do not do a full 5 second durn out other wise they may become a oily mess and not hook!

Also check your slicks every time you get back to your pit area, if they have no gravel, Grass or dirt dust stuck to them , then they are done and you know the story from there!

get rid of the stock front shocks and get some adj or 90-10s so the front can move -- - then try adj the rear tire pressure to a point where it is happy both warm and cold -- work on it from there - and yes dry hops are a waste of time

My Uncle was crew on a stick shift SS car that had a 302 chevy combo. It had an unequal length 4 link.

IIRC, it was around 148 degrees were the track became very slick and it was certain to spin.

I would put a anti roll bar on. When running 10-0years ago made the car much more consistent with stock components. I like the Rhodes sportsman bar.

My main question is what has better bite a hot track or cooler?

Never did a dry hop. Isn't that a 70's thing, lol. I do a high gear burn out and as soon as I feel it start to bite I power out and bring rpms down till the tires grab. I always do the same burn out regardless. Mabey I will try and shorten the burn out up at night.

I had QA 1 R adjustable up front but found they wouldn't settle back down fast enough losing front travel. Had stock shocks laying around and found it to be a lot more consistent.

I have a weld in anti roll bar.

I am running the older ET street bias tires. Have them set at 13lbs hot.

I did find the car likes to leave at a higher rpm to hook in the summer. Not legal to have a box in my class and 3800 rpm launch puts me right at .00 light if I hit the tree.

Going to do some testing at night before my next index race.

I did make it to the finals Saturday and ended up loosing with a .019 light and running a 10.007 on the 10.00 index.

Well to a certain point a colder track is always better hooking.
If it's like 50º or less probably not going to hook as good?

Do you keep track of the surface temp?

:confused:

Might check slick pressure after a burn out to see if the pressure is different than on a warmer part of the day?

Might have to run a different slick pressure on a cooler night?

:confused:

hotter and cooler are relative terms -- over 120 or so and a track can get iffy -- under say 60 or so and it gets iffy -- how long ago was the track prepped ??? it gets iffy -- short burn out on a hot track -- longer one for a cold track. some front shocks are adjustable -- 90-10 , 70-30 - ect. And remember - 60' will change with weather - warm weather = less power = slower time , cool temp usually means better power and a faster 60' -- a weather station and a dial program are invaluable.

To this day I still see racers doing dry hops and I just snake my head!

If you have any power to play with why not a timing control? You already know what the car does with the current suspension in hot and cooler conditions.