BMI's DB12R

Old 11-25-2007, 10:03 AM
  #2986  
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How many are in the mains in Cleveland?
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Old 11-25-2007, 10:38 AM
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Jason Schreffler wound up finishing 4th in the B main. It was an extremely tight field and 3 seconds seperated 1st to about 15th . We are very pleased with the results for the short time he has run the new car. It will only get better as he learns it.
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Old 11-25-2007, 10:44 AM
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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.

Last edited by wallstreet; 11-25-2007 at 10:58 AM.
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Old 11-25-2007, 12:10 PM
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I will get his setup from him when he gets back.

I am going to make wheel spacers for the parmas
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Old 11-25-2007, 02:55 PM
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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.
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Old 11-25-2007, 03:28 PM
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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...
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Old 11-25-2007, 05:49 PM
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Originally Posted by Jonathan
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...
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...
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Old 11-25-2007, 05:52 PM
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Originally Posted by Marcos.J
"I WANT A DB10R"!!!!!
Only if you run mod at the birds!!!!!
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Old 11-25-2007, 05:55 PM
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Originally Posted by protc3
I am going to make wheel spacers for the parmas
'Bout time.....Slacker
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Old 11-25-2007, 06:07 PM
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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...
Attached Thumbnails BMI's DB12R-dsc00204.jpg   BMI's DB12R-dsc00205.jpg   BMI's DB12R-dsc00206.jpg  
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Old 11-25-2007, 06:44 PM
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Thats interesting. Jason and I are going to do some asphalt testing at a new track in a couple weeks and this would be really easy to try out back-to-back.
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Old 11-25-2007, 06:54 PM
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Originally Posted by Trips
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...
Very cool buddy. I wanted to make castor blocks with less arm angle and 2 mounting holes for long and short upper arms. Glad to see that it has been tried out and working.
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Old 11-25-2007, 07:22 PM
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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.
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Old 11-25-2007, 07:46 PM
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Originally Posted by Jonathan
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.
IRS provided this option years ago...

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Old 11-25-2007, 07:54 PM
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My bad... Thank you Chris. I just checked it out... and I am on it..
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