Getting beat down the hill

[ninjarabbi1997]

In our district race we were consistently getting beat by about 1/2 car length down the hill (we caught them on the flat--mostly); what would contribute to us getting beat (besides someone having lighter wheels, the rules are pretty much the same as pure stock, so that shouldn't have been a factor). Or another way to say it, what can we do to get a faster start? We were running camber at about 3 degrees and rail riding.

Thanks,

Jim

[spindoctor]

How far back is your weight? How long was the track. Most likely they were more aggressive. Last year we were able to run some tests on the track. Our cars were very aggressive and they would pull out to a 3/4 car lead. The would barely hang on. There was just one car that could over take us.

[Lucky 13]

If someone is using wheels that are lighter than yours it can have a big effect on the slope.

[ninjarabbi1997]

We were at 7/8" CG on about 32' wood track (very rough joints).

[Lucky 13]

You may have went to aggressive on the weight placement for a short track. If I'm not mistaken (someone correct me if I am) a car with a less aggressive weight placement will fall faster than a car with a more aggressive weight placement but it will slow faster on the flat.

[Da Pine Racing]

On a wooden track I would prefer not to rail ride and even more so on a rough one.

Unless there is a convex curve @ the top of the track or in the drop zone, I don't think the weight placement matters as far as acceleration goes. If there is a convex curve on top, a front weighted car will gain momentum sooner than a rear weighted car pulling it over the arc. On a straight downhill I would think 5oz is 5oz.

Like Lucky13 said, lighter wheels are a major difference during acceleration & will stick out like a sore thumb if some cars have them & some don't.

[Knothead Racing]

Spin, I asked a similar question back in Jan or Dec. in
"ask the pros" / "in need of help". (0107)

Also see WARPs comments on the subject in "Bodies & Weights" / "The Weight" (1104)

Both Builder Jim and Warp's comments helped me out a lot.

[Knothead Racing]

ninjarabbi1997, sorry about that, I forgot who asked the question.

And it's getting too late.

[SpeedGeek]

If I remember my Physics correctly, all object fall at the same gravitational rate, so a car with more aggressive weighting would not beat you to the bottom of the hill. The CG would fall farther resulting in higher speed right at the bottom. So... (all other things equal- BIG assumption) it should pull away on the flat, then lose its lead over distance due to greater instability. If you are getting beat on the hill, I would expect the other car's wheels are lighter (less inertia), or the car is less "frictional" (is that even a word?!?!?).

There's two cent's worth of advice from a racer who has never won a WIRL event. (But we smoked "the Pack" this year).

[festiva91]

Front weighted cars start faster but get passed on the flat by rear weighted cars. (on most tracks with a slope and flat) Gravity acting on the weight longer.

[spindoctor]

Hey ninja we had the same experience last spring...

First off I'll describe the type of cars we build.
Very low profile, aggressively weighted to the rear with tungsten (plates last year).
No wheel modifications allowed. Cars are very fast. Our pack races are on a 32 foot wood Piantodso (sp) track, which equates to about 28 feet of racing surface. The only heats they loose are when the brothers are racing each other.

The district races on a an 50 foot alumninum track with about 48 feet of racing surface. This alumunimum track does not have as steep of an angle to the transition. The transition is 2 full sections (16 feet or about 15 to account for the starting gate).

The question I have is there were about 3 cars that would shoot off the start and get a quick car++ length lead on us. We would not pass them until about the 47 foot mark, and sometimes not until about 2inches after the finish line.

I looked at the wheels and they did not appear to be shaved (illegal). I have only 2 thoughts as to why these cars jumped us. They lightened the wheels or because the track is not as steep as our pack track we did not realize all of our energy from the start.

I am leaning toward the second option, since I don't think they are cheating. Do I need to shift the weight forward for this track or is the rear weight still better? The host pack always has a few guys that have their cars very tuned and running this track in the upper 3.7's or lower 3.8's, we had one heat at 3.796 but most at 3.830's.

[Parrot Racing]

Hey Ninja, I would have to agree with Speedgeek. All things being equal as far as one cars wheels not being lighter than the others, it would seem to be a friction issue. Make sure your hubs are coned, wheels not too tight against the body, and you are all lubed up. Then you should be able to keep even with the rest of the pack on the ramp.

Enrico-Parrot Racing