BMI's DB12R
#2986
How many are in the mains in Cleveland?
#2988
Jason is there a chance you can share his setup ?
I know he was saying it was way different then where it was when he brought it to the race
Also jason, are there any plans to make wheel spacers for the parma pro 38 wheels ? I know alot of the guys running the db12r are running the parma tires.
I know he was saying it was way different then where it was when he brought it to the race
Also jason, are there any plans to make wheel spacers for the parma pro 38 wheels ? I know alot of the guys running the db12r are running the parma tires.
Last edited by wallstreet; 11-25-2007 at 10:58 AM.
#2990
BMI cars looked awesome this past weekend at the florida race. also got to drive the db10 and that thing as awesome. cant wait to get one of these suckers for the birds in feb.
#2991
I got one of these DBR 12 about a week ago because I thought these things on Carpet would be good practice for what I primarily run, 1/8th scale onroad. I received the car (pre-built by Jason) on a Friday and proceeded to race it the next day. I'm kind of new to 12th scale for the most part. Although, I did dabble with an L3 back in 2004... breifly. It was nice when it wasn't tweaked, but somehow it was always not right, and I quickly gave up due to the maintaince. So when BMI introduced a car that you can't tweak, I was like...yeah! I take one with tires please. Anyways, back to the race... As I've said, its been a while... The first time out, I forgot to tape the battery, then there was gearing, and meanwhile the all the screws in the pivots worked their way out. That last one was ugly!. By the time I had everything worked out, I felt that the car was very drivable, nothing weird like I remembered about these cars. But the stock setup was hurting for steering, a disavantage that would put me at more than a full second off the pace. My competition was a contingent of OD 12 team drivers, and they were dialed. So I turned to Jason for his insight and expertise on these little electric cars. After defining the problem as well as I could, Jason prescribed some changes to my setup. I raced again yesterday, I am happy to report that I went from being more than a full second off the pace to within 2 to 3 tenths. That's with no practice, nonetheless. I wish I could say that this thing was dialed right out the box, but anybody that races knows that this is never the case. There is just too many variables. What is important is that the BMI concept is for real. My car was never tweaked. More importantly, this chassis responded very well to setup changes. By that, I mean my car never lost its composure when I dialed in more steering. It just kept asking for more. When this thing is properly setup, it is an absolute beauty to drive. It's only going to get better as I learn. Thank you Jason for everything.
Here are the changes I made to my set up. in the following order
10K in the damper tubes (more stable and responsive in the turns)
1.5mm beneath the shock ball mount. (slightly improved on power steering)
caster shims in the back (more overall steering)
copper rear spring (not Jason's idea, but man, it was nice!!!)
Things that didn't work
10K on the king pins (a little twitchy)
less pod droop 1.5 to .5mm (lost a lot of off power steering)
Things that I will try.
New brace
20k 30K in the tubes
Extra thick side flex plate.
Narrowing the rear.
Things I am afraid to try.
Has anyone tried to shim the arm mounts to lengthen the upper arm? I am thinking this will reduce the amount of camber gain. might be good...
Here are the changes I made to my set up. in the following order
10K in the damper tubes (more stable and responsive in the turns)
1.5mm beneath the shock ball mount. (slightly improved on power steering)
caster shims in the back (more overall steering)
copper rear spring (not Jason's idea, but man, it was nice!!!)
Things that didn't work
10K on the king pins (a little twitchy)
less pod droop 1.5 to .5mm (lost a lot of off power steering)
Things that I will try.
New brace
20k 30K in the tubes
Extra thick side flex plate.
Narrowing the rear.
Things I am afraid to try.
Has anyone tried to shim the arm mounts to lengthen the upper arm? I am thinking this will reduce the amount of camber gain. might be good...
#2992
Tech Elite
iTrader: (16)
Give me a few minutes and I'll get a photo posted...
#2995
Tech Elite
iTrader: (16)
Here are a few pics..
First one, you can see how much longer the upper arm is by looking at the turnbuckle... a LOT more threads showing than the normal way.
Second pic shows the view from below... you can see the cut off 0 degree mount sandwiched in there...
Third pic... disassembled - here you can see the cut-off 0 degree arm mount... pretty easy to do.
I can't say I've felt a lot of difference, but I think it makes the car a little more comfortable to drive when the grip comes up... I haven't really tested a lot, I've been running the old skool front end on my Rev4.5 and now the "formula" front end on my Rev5.
Hope that was clear...
First one, you can see how much longer the upper arm is by looking at the turnbuckle... a LOT more threads showing than the normal way.
Second pic shows the view from below... you can see the cut off 0 degree mount sandwiched in there...
Third pic... disassembled - here you can see the cut-off 0 degree arm mount... pretty easy to do.
I can't say I've felt a lot of difference, but I think it makes the car a little more comfortable to drive when the grip comes up... I haven't really tested a lot, I've been running the old skool front end on my Rev4.5 and now the "formula" front end on my Rev5.
Hope that was clear...
#2997
Tech Lord
iTrader: (13)
I've done that, what I do is take a pair of the 0 degree upper arm mounts and cut away everything above the bolt holes. Then I use them to space the standard ten fegree upper arm mounts. I use a 4-40 x 5/8 screw inplace of the 4-40 x 1/2 incer that would normally hold the arm mount.
Give me a few minutes and I'll get a photo posted...
Give me a few minutes and I'll get a photo posted...
#2998
Very nice Trip! That's exactly what I was talking about... In 1/8th scale, the arm length is tuned to increase or decrease steering via camber gain. Longer arms yeilds more mid corner. I haven't measured it, but on my 960, the difference between long and short is only about 2mm, but it makes a big difference. It's all about the contact patch. Jason, as long as you trying stuff, why don't you make it so you vary the upper arm angle (by raising or lowering the castor block) so there is a different roll center adjustment. Bring these little cars out of the dark ages. You know, like you did with the rear end.
Last edited by Jonathan; 11-25-2007 at 07:34 PM.
#2999
Tech Elite
iTrader: (11)
Very nice Trip! That's exactly what I was talking about... In 1/8th scale, the arm length is tuned to increase or decrease steering via camber gain. Longer arms yeilds more mid corner. I haven't measured it, but on my 960, the difference between long and short is only about 2mm, but it makes a big difference. It's all about the contact patch. Jason, as long as you trying stuff, why don't you make it so you vary the upper arm angle (by raising or lowering the castor block) so there is a different roll center adjustment. Bring these little cars out of the dark ages. You know, like you did with the rear end.
#3000
My bad... Thank you Chris. I just checked it out... and I am on it..