reprep oil

[chromegsx]

Well we are all ready for our race and intitial testing seemed positive for an all kid built car. but due to weather our race got postponed for a week, which unfortunately means I have time to think.

So we tested his new car against his last years car (graphite 1st in speed by half car at minimum) and against a car I built for a fun race (oil which beat his car by (around a full car length on average). This was on super low long slope about 10-12 feet raised 2-3". So this years car is starting with 10" steer in about 7 feet till we get to test on real track, my car only has about 8".

My question is how much will a reprep of my car (oil) and his last year car (graphite) make a difference (neither were reprep) in a test like this or on live track? significant enough to make up half a car or more? Does oil disappear in my car? It was stored in zip lock bag for about 10 months. Probably need to add graphite for his last year car to bring up to par.

 

[Chief]

I would just regraphite his and leave the rest be...

 

[chromegsx]

Thanks Chief. Did this last night... Didn't like the results. Didn't like the low slope results. Seemed to help the graphite car get faster, now I'm not sure which car is faster than which, guess I'll have to wait till test run tonight. After looking closer at the cars it seems our rear wheels are migrating in to the body...At this point I'm wondering if trimming the tread width is causing this to happen (same happened last year, same trimming, but didn't have drill block like this year). maybe once it gets up to speed they go out. but we put 3.5 degrees on them and used a silver bullet style block to drill. I didn't check toe...(forgot) but it should be right on. I'm afraid I might be spending time at the workbench tonight after the test run to see if I can find the problem...Might be good excersize for son if i can keep his attention. On my car that I built the wheels were not trimmed or drilled with a block and work as expected. I spent a lot of time drilling though to get it right.

Do the oil cars never need re-oiled or doe it only make a few thousands difference after a year?

 

[Rocket car]

I re-prep oil after each race (once a month) some guys go as much as 3 months without re-prepping. After 3 months I would do it for sure. You are loosing speed for sure.

 

[chromegsx]

have you tested before and after re-prep to see how much difference it makes? I think i've read the difference this makes somewhere, but can't seem to come up with the right search terms to find it.

 

[SG3 Racing]

I pulled my SR out this weekend, hasn't been ran since winning the Nationals in July. I ran twice with my times being .003 faster than it was before I shipped out in July. I was blown away, I cleaned wheels and
put back in box.

SG3

 

[~JBD RACING~]

I usually make at least 130-150 passes before I even consider re prepping.

 

[chromegsx]

Thanks guys for sharing your experience. Just got back from the trial run and got hit with the hidden rule trick. Apparently no reducing the wheel tread allowed. It was hidden in the "building you car" rules. No kidding. I took this section to be suggestions and glossed over it...as it included gluing axles in, painting and waxing.... What a joke, but I guess other people are reading it word for word so...... THe specifications were on the opposite side of the paper...and were what I used and said nothing about the wheel limitations.

So my question is how much will the extra wheel weight slow the car down, because I don't have a lathe and I heard these wheels (awana) are miserable to lathe any way?????

 

[Kinser Racing]

There's no way to tell, it's a hypothetical question. There are to many variables involved. It will be a little slower all things being exactly equal. But all things are never exactly equal, even on the same car. /images/boards/smilies/smile.gif

 

[chromegsx]

True I know they are not equal for sure although on my cheap wood track they are about equal now. I took video on each and will compare before and after to get a feel for the difference. Probably won't be able to tell though.

 

[chromegsx]

We'll I'm going to call it a night. I got new wheels on and it was slower for sure but I couldn't tell on video for sure. Comparing to last years car it was at a significant disadvantage. Ended up being An inch or so behind when before the switch it was at least an inch or so ahead. after a few bent axles and tweaking it's now at least as fast and tends to pull on the flat now with heavier wheels. I need to take the extra weight back out yet and I want to redo the oil and retest. This car seems to like a lot of drift for some reason. When I brought it home from the tuning at the trial run it was at 28" in 7 feet and beating my car by an inch or so. seems it wants at least 16" for my track to stay straight. Every car seems to be an adventure. So much for getting sleep on the few nights before the race.