Agressive?

[John Thawley]

My track will be here Tuesday... so hopefully by Wednesday many of my questions will be answered.... or.... I may have many, many more. /images/boards/smilies/smile.gif

I seem to be building cars with pretty agressive COM. Last year our car was awesome at a little over .800" - this year we have 3 cars ... one at .600" and two at .545"

However, the two at .545 are also short wheel base.

My question(s): Can you go with a more aggressive COM on a short wheel base car? Also, when running a more aggressive COM, do you set the car to turn in to the rail harder?

JT

 

[Guest]

I say all cars are different. Put as much steer in it as it takes to make it fast and run straight. Some of my fastest cars have a lot of steer. I had one tonight that has 1" in 4'. I thought that can't be right so I gave it 3" of steer. It wobbled all over the place. Put it back to 1" and it ran just fine. That one does have me puzzled. BTW that one with the 1" steer.............it has a 4 and a half inch wheel base!



Sorry John I forgot to mention the length of the tuning table the first go round. I am with OPA and Kinser and don't worry about the COM. After you build a few you kind of get to know where the weight has to be and you only have so much space to put it there.

 

[OPARENNEN]

I am of about the same opinion as Kinser, in that I don't pay much attention to the COM. I put the weight in similar in most cars, even most classes, and then just play around with the movement of the weight and adjusting the drift, and checking the time.

Just for fun, I checked my com on my UNL, which with Kinser broke the track record at the last race. the com was .4375, but that was just the way it turned out. I never set it intentionally. I think the drift is 10 times more important. Since coming home, I did nothing except tighten the drift, and picked up another 5/1000's. but it took 20 timed runs with constant drift adjustments to pick that up.

I also don't pay any attention to puting the car on three different scales, one for each wheel. Maybe there is something to that, but if there is, I will find out later. At this point, at least for UNL and ELIM, I think drift is more important.

 

[John Thawley]

Appreciate the feedback. I guess my concern was that I had pushed the COM to a point were I would not be able to recover if it was too aggressive.

That said, the drift you guys are talking about (I think) kind of freaks me out. Last year our car moved about 3" in toward the rail after about 6ft. When BSB refers to 1" of steer or 3" of steer, what is that referencing. The cars currently drift in about 4" over 4'.

Rears are drilled with cant (using The Block)... front is one up with DFW axle bent down. I'm getting a bit of whirrrring sound from that wheel. Thoughts?

JT

 

[OPARENNEN]

I am still attempting to become competitive in SS and SP classes, so I won't attempt to advise the drift in those classes, except it is almost always over 10 inches, sometimes much more.

However in ELIM and UNL, I start out with a drift of 3 inches over 8 feet. After that, I run a timed run, adjust the drift up or down by less than 1 inch adjustment, and time again. I have 3 cars in each of those classes. UNL ends up between 1 inch and 3 inches, and a bit different with each car. ELIM varies much more. 3 inches on one car, and 7 inches on another.

 

[Kinser Racing]

The sound your getting is normal, it's the fluting on the edge of the wheel.

 

[Guest]

Appreciate the feedback. I guess my concern was that I had pushed the COM to a point were I would not be able to recover if it was too aggressive.

That said, the drift you guys are talking about (I think) kind of freaks me out. Last year our car moved about 3" in toward the rail after about 6ft. When BSB refers to 1" of steer or 3" of steer, what is that referencing. The cars currently drift in about 4" over 4'.

Rears are drilled with cant (using The Block)... front is one up with DFW axle bent down. I'm getting a bit of whirrrring sound from that wheel. Thoughts?

JT

When I said steer it's the same thing as drift............PA thing? LOL

 

[Kinser Racing]

Some people call it drift. But, drift would be the rears sliding out, steer would be the proper term. /images/boards/smilies/smile.gif