Unexplainably Fast Cars?

[DuckOfAllTrades]

I have a car that shockingly and absolutely surprised me. When building our cars this year for our pack race, I had a set of wheels that had been lightly lathed and trued up. Great wheels! But for some reason the bores were noticeably larger than a normal wheel. Seriously, I don't have a pin gauge or way to measure, but you could tell just be inserting an axle and observing the play. Or how easily a normally tight Qtip would slide in. They were larger. I tried these wheels out on 4 cars, each time the same. Erratic, drift 4 inches one time, 2 the next, 12 after that. And they had a horrible wobble that no matter how much I tuned and adjusted would NOT go away.

I also had a body I was using for one of my cars that I had spent a little time on, but decided against using. It's not a wedge shape, aerodynamic yes, but had a series of holes down the middle that I'm sure affects the speed. A good looking car I felt wouldn't be fast, just made for fun and to practice. It has a COG of 1 inch in front of the axle. Not even aggressive, this is before I knew to slide it back.

Since I had decided not to use the body, and the wheels were trash, I plugged them together with decent straight axles. No tuning at all. Just plopped them in. To my surprise on this car, they ran straight and drifted just fine! I was amazed. Out of curiosity, I decided to take the car to tech day to see what it ran. I had to be crazy.

It was the fastest car I had running graphite and within the rules! It ran a 3.661 on it's fastest time on our 49 foot besttrack, it's second run without breaking in the graphite. My daughter's second place car (aka, winner in my heart) only cracked the high 3.7s once for the fastest time of the day!

I had started to give the car to my daughter after I realized it was fast, but we ended up building a new one that I was SURE would be faster than the thrown together car with oversized bores. It wasn't even close. Hindsight is 20-20, she should have raced it on race day.

This brings me to my question. Does anyone else have a tale of a car that is unexplainably fast? That shouldn't be in theory, but just goes?

I just can't get over this car! I may take it to districts for the adult/sibling race.

 

[FDM]

Did you ever try that body with wheels that had a more tighter bore? And were the other wheels you used also lathed and trued? The only way to know if the larger bores had a synergistic effect with that body you would have to run it with wheels which were lightly lathed and trued up the same way but with smaller bores. I am no expert but my guess is that the slots/holes on that body where better aligned than on the other car bodies. And a trued wheel is probably still faster than a standard wheel, even if the bore is slightly larger.

 

[DuckOfAllTrades]

Did you ever try that body with wheels that had a more tighter bore? And were the other wheels you used also lathed and trued? The only way to know if the larger bores had a synergistic effect with that body you would have to run it with wheels which were lightly lathed and trued up the same way but with smaller bores. I am no expert but my guess is that the slots/holes on that body where better aligned than on the other car bodies. And a trued wheel is probably still faster than a standard wheel, even if the bore is slightly larger.

Never tried it because honestly, I don't want to touch it! LOL. Afraid if I do, it will no longer be fast. The body DID originally have different wheels, but had no way to test it.

 

[DuckOfAllTrades]

Did you ever try that body with wheels that had a more tighter bore? And were the other wheels you used also lathed and trued? The only way to know if the larger bores had a synergistic effect with that body you would have to run it with wheels which were lightly lathed and trued up the same way but with smaller bores. I am no expert but my guess is that the slots/holes on that body where better aligned than on the other car bodies. And a trued wheel is probably still faster than a standard wheel, even if the bore is slightly larger.

And you are DEFINITELY right. It has to be better. What's crazy is all four bodies were prepped the same way, drilled with the same jig. So you would think one of them would be comparable.

I guess wheel gap could be another variation? Maybe an axle a little bent? I did use same axles on the other four cars, they were straight but I never checked to see HOW straight.

 

[Darkside]

Never tried it because honestly, I don't want to touch it! LOL. Afraid if I do, it will no longer be fast. The body DID originally have different wheels, but had no way to test it.

LOL!! I know that feeling. We had one this year that was buttery smooth, consistent, and fast right off the bench. Hadn't set the wheel gaps, adjusted the steer, or anything. It just liked to run, so we left it alone and let it run.

 

[Racing358t]

Unlocking and understanding the secret as to why that car is fast will help you be able to repeat it in the future. There has got to be a reason it is so much faster than anything else you built. I'd start at alignment of the rear axle holes. Get some 321 machinist blocks and some pin gauges and check it.

Scott

 

[DuckOfAllTrades]

Unlocking the secret as to why that car is fast will help you be able to repeat it in the future. There has got to be a reason it is so much faster than anything else you built. I'd start at alignment of the rear axle holes. Get some 321 machinist blocks and some pin gauges and check it.

Scott

Great idea!

 

[B_Regal Racing]

Are they scout axles? If so, they are bent. You might have gotten lucky in the installed orientation...

 

["The Fonze"]

Call me crazy but I'm starting to think that TBR and Duck are the same person.

 

[TRE]

Thats the thing about this hobby..you can do the exact samething 3 times and get 3 different results

 

[HurriCrane Racing]

It's happened more than once. I've been to some big races where my second or third fastest car ended up winning. Some cars are just better in traffic or get a better draw.

 

[derby freak]

Yea ive noticed that some of my cars will get a faster run running with faster cars and a slower run running with slower cars ….its really noticeable on a 2 lane track...oh and to answer the question you ask at the beginning of the thread....yea any of my cars that's fast are unexplainable....lol