BMI's DB12R
#5851
Hi guys!
Just thought I'd chime in after a busy weekend at 360 Raceway.
As everyone else has said so far, the changes Jason made to the DB12R have definitely improved the handling of the car. The setup I used on the car was actually more of a conventional setup than what I used at SnowBirds. The car was VERY smooth and very easy to drive. I still do have to work on fine tuning some things to my liking, but that'll come with more track time.
It was also fitting to be able to mix it up with the likes of Donny, Jari, and Dave G. They were all quick and made the racing exciting.
Anyway, you guys won't be disappointed with the update. The changes really did help the car.
And no, the car I ran at Cleveland was not the UPDATED car.
Just thought I'd chime in after a busy weekend at 360 Raceway.
As everyone else has said so far, the changes Jason made to the DB12R have definitely improved the handling of the car. The setup I used on the car was actually more of a conventional setup than what I used at SnowBirds. The car was VERY smooth and very easy to drive. I still do have to work on fine tuning some things to my liking, but that'll come with more track time.
It was also fitting to be able to mix it up with the likes of Donny, Jari, and Dave G. They were all quick and made the racing exciting.
Anyway, you guys won't be disappointed with the update. The changes really did help the car.
And no, the car I ran at Cleveland was not the UPDATED car.
#5852
Great job and support!!
E
#5854
Tech Fanatic
iTrader: (13)
The only thing that comes to mind that is similar was when Trinity would mill out battery slots and a hole to lower the motor in a Losi Streetweapon chassis back before Losi did it themselves on the IWC version of the car. I think it around $20 per chassis to have them milled out.
#5855
Tech Adept
Jason,
In your opinion is a "gear ratio a gear ratio" or does running different size spurs give you different results in terms of torque? Assuming the rollout is exactly the same in all situations.
Hope that makes sense...
Jeremy
In your opinion is a "gear ratio a gear ratio" or does running different size spurs give you different results in terms of torque? Assuming the rollout is exactly the same in all situations.
Hope that makes sense...
Jeremy
#5856
Tech Champion
I've heard this in the past that a bigger spur will give more torque because it has more leverage on the axle and that a smaller spur will be higher top speed due to the smaller mass of the gear. Personally I think the torque theory cancels itself out. I'd have to do the math to figure it out for sure. Think of it this way, yes a larger spur is going to have more leverage on the axle but to keep the same roll out or gear ratio means going to a bigger pinion as well, and the motor is going to have a harder time turning the bigger pinion. My guess is that the 2 cancel each other out.
On the flip side a case can be made that a smaller spur will give you both more top end and torque due to it's lighter mass makes it easier to spin. But then the same question comes into play...does the effect of the reduced mass outweigh the reduction of leverage from the gear.
Even if they don't cancel each other out, any gain would be so minor as to be nearly indetectable...Anyway that's my theory
On the flip side a case can be made that a smaller spur will give you both more top end and torque due to it's lighter mass makes it easier to spin. But then the same question comes into play...does the effect of the reduced mass outweigh the reduction of leverage from the gear.
Even if they don't cancel each other out, any gain would be so minor as to be nearly indetectable...Anyway that's my theory
#5857
Tech Elite
iTrader: (51)
Join Date: Feb 2002
Location: Comin at ya from a distant galaxy
Posts: 2,930
Trader Rating: 51 (100%+)
Hey Jason
Sweet!!! great news, cant wait to get one for sure
Sweet!!! great news, cant wait to get one for sure
Hi guys!Just thought I'd chime in after a busy weekend at 360 Raceway.
As everyone else has said so far, the changes Jason made to the DB12R have definitely improved the handling of the car. The setup I used on the car was actually more of a conventional setup than what I used at SnowBirds. The car was VERY smooth and very easy to drive. I still do have to work on fine tuning some things to my liking, but that'll come with more track time.
It was also fitting to be able to mix it up with the likes of Donny, Jari, and Dave G. They were all quick and made the racing exciting.
Anyway, you guys won't be disappointed with the update. The changes really did help the car.
And no, the car I ran at Cleveland was not the UPDATED car.
As everyone else has said so far, the changes Jason made to the DB12R have definitely improved the handling of the car. The setup I used on the car was actually more of a conventional setup than what I used at SnowBirds. The car was VERY smooth and very easy to drive. I still do have to work on fine tuning some things to my liking, but that'll come with more track time.
It was also fitting to be able to mix it up with the likes of Donny, Jari, and Dave G. They were all quick and made the racing exciting.
Anyway, you guys won't be disappointed with the update. The changes really did help the car.
And no, the car I ran at Cleveland was not the UPDATED car.
#5859
Tech Lord
iTrader: (13)
I understand what you mean. Gear ratio is gear ratio to an extent. You can get the same gear ratio with a 100 spur as you can with an 88 but the larger the pinion(that you need with a 100 spur) will make the motor freewheel so to speak and have the effect of a large flywheel. This helps keep up your corner speed. I always try to run the largest spur i can that will allow me to achieve my desired rollout.
#5860
Tech Fanatic
iTrader: (2)
New Parts, New Parts, New Parts.... Jason you have done it again!!! The only question for me good buddy is when can I get my 'grubby lil hands on them".
Great to hear about how well they worked and congrats Schreff on another great race!! Please tell Yari that he better be back at the Carpet Nats in March at the Gate and that I said hi.
Great to hear about how well they worked and congrats Schreff on another great race!! Please tell Yari that he better be back at the Carpet Nats in March at the Gate and that I said hi.
#5861
Tech Fanatic
The larger you can get both the spur gear and the pinion, the more efficient the drive. Large spur/pinion combinations allow more teeth to be in contact, so sharing the load and reducing the angles of approach and departure of the teeth. This is also what you see as Jason's 'freewheel' effect - it is a smoother mesh so it will roll better.
However - the larger the spur and pinion together, the larger the rotating weight and so the slower the acceleration of the drive train. For our purposes, this can be ignored, and the weight difference is very small compared to the overall weight of the rear axle in total.
The leverage effect of a large spur is a spurious argument. These are rotating forces, not linear ones, and the 'leverage' is about the ratio itself, not the sizes of the spur and pinion. If your surmise was correct, a vehicle gearbox would be twice the size to take advantage of this effect!!
The advantages are miniscule, ceratinly less than one missed apex or one clipped corner marker. Find a ratio that works using what you have in your box and drive better - that'll get you the results!! HTH
However - the larger the spur and pinion together, the larger the rotating weight and so the slower the acceleration of the drive train. For our purposes, this can be ignored, and the weight difference is very small compared to the overall weight of the rear axle in total.
The leverage effect of a large spur is a spurious argument. These are rotating forces, not linear ones, and the 'leverage' is about the ratio itself, not the sizes of the spur and pinion. If your surmise was correct, a vehicle gearbox would be twice the size to take advantage of this effect!!
The advantages are miniscule, ceratinly less than one missed apex or one clipped corner marker. Find a ratio that works using what you have in your box and drive better - that'll get you the results!! HTH
#5862
Tech Champion
The leverage effect of a large spur is a spurious argument. These are rotating forces, not linear ones, and the 'leverage' is about the ratio itself, not the sizes of the spur and pinion. If your surmise was correct, a vehicle gearbox would be twice the size to take advantage of this effect!!
But again as I said what really matters is the ratio itself...getting the same ratio with a small spur gear or a large spur gear is so minimal in difference that you really won't be able to notice it.
#5863
Tech Elite
iTrader: (64)
Join Date: Jun 2008
Location: Conducting aggressive board meetings at my local track
Posts: 3,301
Trader Rating: 64 (100%+)
The larger you can get both the spur gear and the pinion, the more efficient the drive. Large spur/pinion combinations allow more teeth to be in contact, so sharing the load and reducing the angles of approach and departure of the teeth. This is also what you see as Jason's 'freewheel' effect - it is a smoother mesh so it will roll better.