Originally Posted by
WesRaven
Howdy my fellow Awesomatixians. Had a chance to do some testing at the Tamiya USA track over the weekend, and wanted to share my findings. I'm going to be running 17.5 at the Reedy TC race being held at Tamiya in May, and I have been unsure which car I want to run; shaft or belt? So I setup both cars with near identical electronics and setup. Both cars running Reedy ESCs with two Team Powers motors set to produce similar numbers on an analyzer with identical FDR. I ran the same body, tires, and battery for all runs. Both cars were completely rebuilt with new bearings and fresh grease/oil, and both weighed in at 1390 race-ready (weight added to both, and balanced with a 4 corner scale) sporting carbon chassis.
I drove both cars using the same line, but at the end of it all the A700 was able to pull off .2 faster lap time, with .1 faster average time over a 7 minute practice run. Throughout the weekend my average lap times were within a tenth or two of my fast lap, so both cars were extremely consistent.
Both cars were stuck to the track (the track was incredible on Saturday; perfect conditions and high grip all day) but the A800 was noticeably easier to drive and seemed impossible to get out of whack. This would be the car to drive if I was super nervous about making a mistake and just wanted something easier to drive and completely predictable.
On the A700 if you really irresponsibly hammered the throttle at the wrong time the rear end would step out, but this seemed like an acceptable trade off for how noticeably quicker it was accelerating out of turns with proper throttle application. I didn't have either motor dialed for optimum performance, I just wanted them to run as similar as possible, and even with the same FDR the A700 was able to hang better with other cars in the straight. Even though the A700 felt quicker, it came off the track 10-15 degrees (F) cooler than the 800.
So, while I couldn't love my A800 more in mod, the good old A700 is still my choice for asphalt stock racing.
Here's a link to my setup
Edit: One final thought as I re-read my post was "of course the shaft car would do ok with an underpowered motor", so I just wanted to point out that even after dropping in the properly tuned motor I plan to run at Reedy the A700 had no on throttle traction issues whatsoever (and I lowered my fast lap another .4)
Weirdly, I just did a similar exercise this weekend in the UK on my club track. Although with slightly different electrics (muchmore fleta pro in a800 and reds racing tx120 in evo2), I ran the same setup on my evo2 and a800 Carbon, with identical gearing etc in 13.5 boosted. On this particular circuit the a700 evo2 with the flexible alloy chassis felt faster.
I did about 5 runs on each car, making specific changes to improve each car. The evo2 felt like it rotated in the corners quicker, with a more planted rear on turn in than the a800. The track is unprepared and very low traction, with no additive allowed, so this might be down to the increased flex in the softer alloy chassis.
I'm convinced I could have worked on the a800 and made it as fast with more time, but on this track the a700 was dialled in quicker and gave me the TQ and win on the day.
Good to know that both cars are relevant, and both have their strengths. It seems very circuit dependent so I'll be taking both with me to the Nationals. The a800 was faster than the evo2 at the recent Cotswolds national, and there are some drastically different circuits on the calendar to come. Looking forward to seeing which is best next time.