Weight Placement

[jrbryant68]

If it said ounces it wasn't me bud. Anything I have ever said would have been in grams.

So I am running a std whell base with 12 cubes behind the back axle and 6 in front... it is a heavier car body, but it is running 2.99 2.98 Am I too aggressive? would shifting 7/11 be better than the current 6/12?

 

[derbydadgeek]

Sounds like the bumps on the edge of the dfw running down a tuning table.... Sounds correct to me.

Thanks 5kids! First time trying "bend it till it just fits."

 

[derbydadgeek]

Good luck... hope you whallup the competition!!!!

Thanks buddy - we're pumped!

 

[derbydadgeek]

Thanks for all the help! Car is lubed, tuned and ready to rock. Nice to find such a great group of guys willing to give a couple of rooks some pointers on how to go fast. Really appreciate it!

 

[BulldogRacing]

tread bumps, it's normal and it's going to rock!

 

[W8NONU]

Something not working very well in the car test.
You are getting way too much time change for such small adjustments . Imagine your time if you moved all cubes to the center of the car- time should still be under 3.055 sec.

Just a minor point but the max-v tests all kept the same cg.
two of your tests should have had the same cg if you were just moving around without changing distance from axle.

This is true but in the OP's 1st post he moved the CG. I just expanded on his theory. Although B_Regal says I'm "finding out what the cars wants", I still believe a laterally balanced car will be easier to tune.

 

[txchemist]

You are missing my main point- something wrong with your car to produce the data you got.

 

[txchemist]

Or a fender drag with some weight change
When you get time, repeat without fenders and see if that changes your mind

 

[W8NONU]

You must be talking about the difference between test #1 and #3. It is possible I included self induced error such as high and low times due to staging. I logged all the times. I'll go back and review the data. Test #1 and test #3 also moved the CG laterally which isn't represented in your graph. I believe you're right. The difference in times indicate further testing is needed. I'm all about trying to eliminate these inconsistent variables.

Test #1
.660 in front of rear axle
.008 right of center

Test #3
.656 in front of rear axle
.0355 right of center

 

[derbydadgeek]

We ended going with this configuration:

XXXXXX
XXXXXX

XXXXX (centered)
XXXXX (centered)
X

COG = .57

Showed up and saw we were racing on a homemade wooden track - almost had a heart attack! Car was pretty loose, but it got the job done. Best part was when my son asked if we could get a track and mom said she thought that would be a lot of fun. I agree!