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View Full Version : Mid Mounted Mayhem!!: It is a possibility! (A how to)


potentiality
02-11-2004, 07:23 AM
Have you all seen that there is room in the rear pod to switch the motor and diff to make a mid mounted motor (better handling. turning). The three things that would have to be overcome are this:





A: The chassis and upper brace would have to be about a 7/16" (havent really verified this yet) shorter. You could use some epoxy and some fiberglass strips to reattach. It still wouldn't be perfect, unless you bought a sheet of carbon fiber and cut one out yourself.

B: The rear pods halves would have to be drilled with a 2mm drillbit on the direct opposite sided of the pods to hold the rear spring. As far as holding in the bearings/bushings since now they would be to the "inside". Anything to 3mm orings, to a 3mm shaft that you put on as you install the diff through the pods would work.

You could also redrill the spring retainer on the main chassis to the middle of the upperbrace, and keep the stock brace "flipped" around on the rear pod. If you went this way though, you would
not leave any room for placing electronics on the brace.


You could avoid all of the above by running the motor and diff reversed. But if the motor is timed, you are ruining your speed, since you would have decreased the timing by those degrees in forward. (Unless you popped the endbell and rotated it 180 degrees). This would be the simplest solution, but then you couldnt switch motors with friends easily.


C: To allow for 6 cell AA packs, the servo would have to be mounted to the front of the chassis, and the body posts redrilled about 1/4" out further on the front support.

You'd flip the whole steering assembly around, and notch the upper chassis where the servo arm contacts so it could still rotate under it.

You might have to get bodies with more "bulky" front ends though, because ones with too much slope (like a GT) could possible not fit if the rear of the servo sticks too far forward. So Sedan types should work fine. You'd also definetly want to give yourself a front foam bumber since a head on collision would end up hitting the servo.



Of course the stock electronics holder would no longer work, so you would have to take them out of the covering, shrink wrap them, and place where your could with servo tape.

What do you all think? Am I on to something? I dont have any fiberglass sheets nor equipment to try this on sitting around.



Would it be worth the trouble? I really think so if your a driver. Better steering, and quicker response. Plus more even tire wear between the front and rear since the weight transfer would be shifted.

avenan
02-11-2004, 11:23 AM
Very doable -- and fairly easy to do. The way I did it was to actually turn the motor mounts so they mount on the same side they originally did, but turned 180 degrees -- so where the bearings or bushings used to be is on the inside. I then (carefully) removed the flanges in the mounts, and used flanged bearings. This way, the bearings are on the outside of the motor mounts, and there are no issues with the hubs rubbing the motor mounts.

To combat the length issue, I would suggest building a new t-bar instead of going after the whole chassis. Instead of trying to fit a stock DRR body, which look pretty terrible to begin with, look at the long wheelbase ABC bodies. The 115mm wheelbase versions should be fitable with a new t-bar. You'll need to play around with how to build the tbar -- its a combo of shortening it, and moving the mounting holes for the motormount as far towards the front of the car as possible.

I wouldn't worry too much about getting the stock spring suspension to work. It's very prone to binding. If you want to use it, you can attach the plastic bar to the motor mounts by drilling holes in the appropriate place. OR, you can take the original t-bar, remove the tab portion. This should give you a square piece of fiberglass. Secure this to the original holes in the top of the motormount, and you should be able to mount the spring wherever you want it.

As far as the battery goes, when I was running in this configuration, I had no issues. The standard rechargable pack fitted. Another option would be to pick up the Qualcomm 7.2v Lithium Ion packs allelectronics.com is selling. They're too tall to fit in the space between the chassis and the brace, but placing a couple of small washers between the chassis uprights and kingpins, and the upper brace, should allow you to get the couple of millimeters you need. The qualcomm pack is slightly narrower, so you have more fore to aft space. Should allow you to leave the servo alone.

There was a thread months ago (maybe over a year?) about doing the midship alterations. Using your ideas, some of what I mentioned above, and that thread, you should have no trouble.