Now I'm in trouble.. I bought a MR-4TC Special.

[sschering]

New car coming..
I lot my mind temporarily and threw in a minimum bid on a Yokomo MR-4TC Special..

Turns out I was the only one. It'll be here Friday.

Comes with a Novak Rx. LRP brushed esc and a stock motor..

any problem with these and a 25.5 brushess? I'd like to try Vintage Trans am.

[Mr. ED]

25.5? I don't think this car is suited for crawling

It can handle a much hotter moter.

If you really want to use a 25.5 you'll need to put a huge pinion and tiny spur. But I guess the SP comes with the spur adapter , so it would be possible.
The slots for moving the motor: adjust the meshing are very short. So you'll have to do some measuring to find the right combo of pinion and spur.

To replace the spur you have to take the rear apart; probably the weakest point in the design of this car.

Should any of the alu arms be bent: the MR4 TC I got a while back looks like it has received arms of a later MR4 version.

[terry.sc]

Considering a version of this won the ISTC Worlds, I don't think it would have any problem handling a 25.5.

It uses standard spur gears, so gearing won't be a problem.

[sschering]

Its the spec motor for the Vintage TA class.
ANy 4wd touring chassis, Blinkey mode esc, 25.5 motor,2s lipo, spec tires and bodies.

I was going to run the 70 Trans AM body.

Most people are shooting for a 4.0 final drive ratio.

I'll have to see what I get for gears when it arrives.

The plan is to run it as is in Novice till I get things sorted out and work it up to VTA specs as I get better with it.

[Mr. ED]

When I was running touring cars in Japan we had to use a 30turn brushed motor and were not allowed to go below 6.
4 sounds crazy to me , but so does 25.5 turns What kind of KV are those rated at?

Do you have stick shaped LiPo packs?
I don't : had to rework the bottom of the chassis and remove a rib to be able to stick a brick shaped pack in.

[sschering]

KV on the Noval Ballistic 25.5 is 1,550 RPM/volt
http://www.amain.com/novak-ballistic-boss-vta-sensored-brushless-motor-255t/p262195?utm_source=Google-Base&utm_medium=cpc&utm_campaign=Product-Feeds&gclid=CI_E0_egnsMCFcdj7AodkQMA0g

Here's the class rules
http://www.usvintagetransam.com/rules/index.html

[Wazza22]

I run one of these outdoors in modified with a 5.5T ! You will be fine with a 25.5T. The only thing I have done apart from 'adjusting' the bottom deck to fit hard case lipos is to fit steel diff out drives for durability with the mod motor. the plastic outdrives will be fine with your choice of motor.

Cheers

[sschering]

Looking at the pics it has metal outdrives.

I don't know if they are the aluminum ones that came with the special or steel replacements.

[Wazza22]

Yes the front outdrives on the one-way diff are steel already. The cars came with plastic/delrin ball diffs in the rear as standard.

Cheers

[littleVETTE]

there was also the optional steel front outdrives for the mr4's. i think the number was zs-501s

[sschering]

After the first trip to the track we found lots of bugs to sort out.

The ESC would start out hard and fast then slow and run about half speed.

It was also a model without reverse. That became very annoying chasing the car down to free it all night. (kids was driving)

The steering was binding and wouldn't hold trim.

I had the oneway front diff working but by the end of the night it was freewheeling on the right side again.

I took it home, tore it apart and found a few things..

The front a arms were installed upside down flipped left to right causing the suspension and steering blocks to bind up.

The oneway broke a bearing cage.. it was toast.. It's now glued up as a spool.

As for the motor I swapped in a Novak GTB and 17.5 brushless.

It's running good now.

[mamadoesntletme]

The special version is a nice car, I had one I bought in the auctions but I quickly sold on ebay. But it is a great vintage touring car, together with the yr4 series.
Now it needs a cool body!

[sschering]

It came with a body.. nicely painted but beat up a bit.. It's serviceable till I get a VTA body. I'll probably get the AAR Cuda for it.

[sschering]

This is the body. beat, dirty but it's got some style.
I put the old wheels on for some street testing.