I like it! I did a similar thing recently though i'm running a rear motor 22 with the side shorty and the speedo behind the battery.

So far, i prefer it over my b4 w/bb and the stock losi 22. has all the positives of the 22 (forgiving handling and parts quality), and the stability and rear traction of the b4.

nice work.

Had the car at the track a few days ago and had some issues putting the power down. The slightest bit of steering input while applying the throttle and the car came around. I tried a ton of things including making the wheelbase shorter and adding weight to the rear end and nothing worked, I felt no difference.

I think it was the gear diff I had in the car with 4000 wt oil. I stood on the track and watched it and noticed the car diffing out a bit the around it went! Even when it did hook up and weight transferred to the rear the car wandered badly down the straight. Unfortunately I didn't have time to throw the ball diff in it and test it. That will have to wait for another day.

I am looking forward to seeing the difference and trying to figure out the problem. If the ball diff cures the problem then I want to try the gear diff with something like 20,000 wt oil to see what that does.

Planning to go to the track this weekend and do some more testing. Ill try to get some pics and possibly some video.

Try taking away some anti-squat, and maybe adding some pro-squat. I know I've said it before, but if you still can't get the stability or on-power traction this will help tons. I also notice your running calibers, so traction is probably quite low....... good luck to you.

I have taken the car to the track 3 times now and I finally have the car handling well. My biggest problem was tires. Once I changed to clay compound the car really started to work. I had the fastest 2wd car in practice, and just had a few minor handling issues that might have simply been driver issues. The car seemed to hook fairly bad when turning into the face of a jump or a bump in the track. Gonna try some geometry changes and maybe thicker shock oil next time. But at least it pulled a few of wheelies, one slap wheelie and a few when hitting bumps. Finally getting that forward traction.

Ill post some pictures and front / rear weight bias numbers after all the mods I've done since the pics. Prolly include the setup as well.

By the way I picked up a B-Fast diff rebuild kit. KICK ASS! That builds a nice diff.

Any updates on this mod? Thanks

i tried the shorty pack sideways a year and a half ago. it works fairly well. other than the servo relocation i started flipping the arms and turning the pack sideways. haha.

Matt

I just don't see how 63% of the weight on the rear is more rear bias than the car was in rear motor. Every 22 I've ever seen have 67-68% rear bias in rear motor. My CR2 (mid motor XXX) had 63% stock and after I made a new chassis and went crossways with it I ended up with 68% rear with no added weights. The X6 is over 65%.

There are 2 types of rear traction that people get mixed up. The first is forward traction. With the 4 gear setup you shift tons of weight rearward so wheelies on a mid car can actually be easier than a rear motor car. I fought this like crazy on my CR2 and came to the conclusion that a 3 gear mid setup would be better since the second form of rear traction is more important.

That is sideways traction. If there isn't enough weight on the rear wheels they slide out going into a corner and it slides around when you get on the power mid corner. A 4 gear setup may shift weight onto the rear wheels but it will do it at the expense of front traction which reduces steering.

My opinion is that an MM3 setup with 78%-79% rear bias and little to no anti squat is the way to go. I liked it much better.

Sorry for not posting any updates lately, I have been crazy busy and haven't been to the track in a long time. The good news is that there is only one week of teaching left and two weeks of cleanup after that then I am off for the summer! I plan to do a lot of racing, practicing and fabricating.

I haven't posted pics of the car since I got it running. Although I have plans to develop the idea further and do a body with a nice paint job there shouldn't be any massive changes.

Since my last post I have changed my shock package and went to some thicker oil. I also added two pieces of lead to the rear bumper. The weight bias is now 65.3% rear and 34.7% front with a total weight of 1505 grams. I do want to try and remove a little more front weight so I can get rid of the lead on the rear bumper.

After making the changes to the car it became very easy to drive. It no longer rotated in the corners but carved them. If I did get the back end to break loose in a corner it was very predictable and easy to recover. It didn't have that heavy pendulum feel of a rear motor car. The car is also very easy to control in the air with the centered mass.

A couple of pics of the quickly painted body. I plan on doing a nicer paint job when I have time.







The new body fits the chassis fairly well, when I switch to outdoor racing I will see how well it keeps the dust out.



The lead I added to the rear bumper.





Pics of the bell crank as it is right now.







Flipping the ball studs upside down allowed me to get the steering as close to the chassis as possible, eliminating the slight bump steer I had before. There is NO BUMP STEER any more. The standoffs allow easy adjustment of this.





This battery hold down was going to be temporary but I like it now. The standoffs are something I found in my junk box, I think that they are OLD Ofna shock standoffs with big washers on top. I do plan to turn my own custom standoffs at some point just so its prettier.





Pics of the ackerman with this setup.




Now I have to make it work as well or better for outdoor racing this summer!

Here are some update pics on some of my other projects.



Link: http://www.rctech.net/forum/nitro-of...ory-build.html

I am learning to use Solidworks and designing a new 1/8th buggy. Next week I should be picking up my own CNC machine! It needs some work but when its working it should be awesome.



This car is now stupid fast! I think that this is the first car that makes my butt pucker every time I squeeze the trigger. It is far faster than my driving abilities will allow. It is also very well balanced and rips through the corners without over rotating, it just carves.



Link: http://www.rctech.net/forum/electric...t-xx-24-a.html

Here are a few pics of my latest changes.



I wanted to experiment more with my idea and try to centralize the mass more and make the weight bias adjustable so the car would work on loose and medium to high grip tracks, and feel the difference of changing weight bias.



You can see how far back the servo is now. Its just shy of an inch further back.





I removed the motor cover piece and trimmed the motor plate and gear cover to move the battery back. This allowed me to move the servo way back. I moved the esc on top of the battery to get even more weight back. I installed a Tekin esc when my Novak final died after I think close to 8 years of use. I am switching back to a Novak because the are far smoother and linear IMO.





Without the brass weight system the car is at 67% rear weight bias.

Ran it a few weeks ago and it started to get pretty quick toward the end of the night, despite having the wrong front tires and not having raced in almost 3 years. Came in 3rd overall behind 2 fast guys. And this was on a fairly loose surface. I was in the lead until I made a mistake.


Might take it to an indoor clay track this weekend and play with the brass weight system I just got to see the affect. With the weights in place the car now has 68.5% rear weight bias. I want to try combinations of longer wheel base and different weights to see the affect.

Ill try to get some better pics soon.

Had it at the track a few days ago for some practice. I left the brass on and liked it as it was. I definitely have more forward traction. It was spooling the diff so that needs to be adjusted, I'd like to try the gear diff again to see what that does.I think that with the diff tightened i can tighten the slipper a bit and get better acceleration out of corners. I think I have everything where I want it I just have to switch the esc out for the Novak and mess with the geometry and shock package to make it perfect. Hopefully the next time I'm at the track I will be feeling better and drive better to see what its really doing.

I'm always interested in experimentation but I can't help understanding what was the point about weight distribution.

What you got there is basically what I got putting my lipo in the front... I'm running on carpet most of the time and the car has a lot of traction and enough steering...

I'm not sure of what you are trying to achieve? I mean what negative behaviour are you trying to fight with such disposition?

Mine:

Rear 930.3g (61.32%) Front 587g (38.68%)

Double post, sorry!

(Damn quick reply is not quick anymore!)

WHAT? Triple post! Wow, sorry again...

He's trying to combat high moment of inertia by centralizing mass. I used this concept when designing a putter last year (except I wanted high MOI so that the face rotated slower).

The concept of MOI can be understood by looking at a ice skater. Stick your arms straight out (with weight away from your center of rotation), and the skater spins slowly. Bring your arms in towards your body, and the skater spins faster.

So by centralizing mass, the car will rotate quicker in corners (in theory)- it's not just about weight distribution to the tires.

Your design looks similar to the new Serpent mid motor, though the steering servo is in a more traditional position.