TOPIC:

What size pinion are you using? I think he has a 14 tooth with a standard johnson silver can. Not amazingly fast, but he must learn to drive it smoothly around corners. He has a heavy trigger finger.

I use a 20T pinion but then again I also use a (RD) 99T spur - so the ratio is 4,95.
Smallest one possible in racing developed pinions btw... but I have up to 25T at the moment.
It'll be fast enough with this motor already so I thought I'd start low.
No idea yet how fast it will be really.

Actually, you guys are using the same gear ratio. A 70T spur with 14T pinion also makes 1:5...
Think you can go up to 18T with the basic Gr.C motor mount set up.

Edit : a silver can is good to get a feel for the car.
It probably came with a Sport Tuned originally like the other Group C chassis cars.
Lucky enough to have a vintage specimen here (the newer one's outside is shinier) for the shelf car build.

I also have the Johnson with 4 air vent holes in it. This one revs to 19000 rpm as apposed to the 17500 rpm of the standard kit motor.

Two hole


Four hole


If that doesn't work, then we also have the Sport Tuned


The four hole johnson was brand new in my Hummer kit from 1996, I even ran it in, in water. After which my other friend ran it on the dyno to produce 103 n/mm @ 19006 rpm, and a stock johnson produces 75 - 80 n/mm @ 17000 rpm.

Cool info. Always very interested to know stuff like this.
I'd love to be able to test motors like that. What equipment are you using for that exacly?

The 17T Lrp in the C11 should do 31.000 rpm btw. And 185W / 25A drain with load...
Very promising on paper.

Louisbaby wrote:

I even ran it in, in water.

I did that with the 23T smaller brother of the Lrp too.
Water resistance is still one of the biggest advantages of brushed over brushless.

Check this out - just beware of the volume :

Not sure of the name of it. You put a lead flywheel on the motor, install the motor on a mounting plate, then plug it in to the machine. Plug a 7.2 volt stick pack in the machine and hit the start button on the computer program. The computer program then speeds the motor up and down and spits out a reading. PM me your Email address and I'll send you a clip of it in action.

Will do. Love this part of car building too...

On the Dutch Tamiyaforum ( Tamiyagekken.nl ) there is an active Group C topic with some real fanatics.
Have to say these posts discussing not only the Group C chassis but also the cars in general has been very educational.
Especially for the crossover info into the other models...

One of the guys (Ducdennis) pointed out that the arms of the front end seemed to be out of shape :



I had noticed they were a bit off when I built the car but convinced myself it belonged that way.
Looking at other images, I am now sure they are bent way too much - probably the result of a crash.
I've seen other evidence of this on the car too.

On Lars' vintage C11 they're straight at least :



Same member that made me aware of this, recently built a reissue C11 (dark box) and posted a build thread.
Although the text is in Dutch, it should be an interesting "read" because the pics of the details are great :

Mercedes C11-Le Mans-Group C

So fixing (maybe customizing) these arms will be another point of attention.
A weak spot in the design of the car...

Edou wrote:

...
...I am now sure they are bent way too much - probably the result of a crash.
...

I don't know - the position of the bends looks suspciously even - you don't think it was a former owner trying to increase camber?

Camber seems to be all the rage in 1:1 motorsport ATM - at least on the evidence of the ludicrous levels of camber run in F1, and even more so in the BTCC this year ... my own view on camber is that a little can be a good thing, but if it's visible, it's too much

I think the the owner before you heated them up and bent them to create camber. If you have a spare one, try cutting it here:




And them some how drill and tap it to add adjustable camber setting. something like this:

www.wonderlandm...r-arm-set/

Just something I would try.

P.S My mate and I got some time on the track yesterday with the street devil. She handles very well for a chassis with no downforce...

Great info, guys! Hadn't thought of the possibility of it being created this way purposely.
But I did notice the slight increase in camber which is not a bad thing...
The car had a crash before (I'll show some pics of the light units later) but I guess it did not bend the arms.

I've been brainstorming about this mod before. Didn't really seem that logical to do but now I have a good reason for it.
These German guys here have been busy on this stuff too :

Pro10 Group C cars

I can only link to the main page btw so please click on "1990 Tamiya Gruppe C" there...

@Louisbaby : nice going with driving the car! Gonna get to it myself soon - hopefully.