No, the 4600 will run on 3s (after all the sticker says it will). However, the 4600 is a little smaller than an S motor so you might start having heat troubles. I know someone over at the Traxxas forums has a single 5700 on a 2wd emaxx and swears that it runs fine, but I dunno.
If you plan to do this "just to see", that's fine. But I honestly think you'd be happier with a single XL motor on 4s, or better yet 5s.
Yeah, I know the vehicle/guy you mean, but something is rather fishy there. I tried 2wd with the Gmaxx the other day when I did that video, but there was no difference at all in power/speed/wheelies. Unless the MM is that much more powerful than The Hv6.5 I think its better to go with a single XL or L motor, or twin S cans like suggested. Heck, S cans are so cheap its even tempting for me.
This was for semi serious fun but don't want to blow 70-100 on an extra motor setup (an extra 7L) is not going to make much diffence - I would be going from 1800KV to 3100KV though so would expect 40+MPH speed? Am i close?
Well I now have a second motor - I'm just waiting for mike to get the mugen motor mount in stock and then i'll place an order for the pinion and I'm done.