I am fairly new to brushless and I have a few brushless questions.

First what would be a good ball park roll out for a 3.5 motor on a 80X40 track? (4 cell)

Secondly I made a few laps with the car just for kicks the other day and it shut down. After giving it a few moments I could take another few laps then it would shut down again. I thought it might be overheating but yet the motor was not hot to the touch. I bought the motor used. I am using a GTB but I have taken the fan and heat sink off as I am currently only using 4-cell batteries.

Any ideas on what could be shuting it down? I know I was over geared at the time but the motor never got hot for the amount of laps I put on it. My main concern for now is making sure it is not the used motor that is bad.

The ESC is over heating not the motor. It's weird with mod, the motors are cold but the ESC gets hot.

First thing to check is the factory drag bake setting. It's probably at #4. Cycle this around to a number #1. This will reduce the heat generated in the ESC. Also add the fan back on.

I'm guessing the run line at about 155' so a ball park roll out would be about 1.15.

Another tip is to add about 30% negative expo on the throttle setting. This will make it a little easier to drive off the corners.

At What Temp Should The Speedo Thermal? 150-155 Doesnt Seem That Hot But Thats Where Mine Was Doing It This Weekend When I Geared Up To Try And Make A 4.5 Run With A Couple 3.5's

Zero Drag Brake But I Think The Minimum Drive% Was Topped Out.

160 degrees is the thermal cutoff, so when you hit that by the time you get to the car it's probably cooled that much. I assume it was a GTB, was it the 4-cell or reg. GTB?

You probably won't be able to run a 4.5 against a 3.5 no matter what you gear it.

Reg Gtb. It Ran To The 3:30 Mark Before Deciding To Pull Over Every Other Lap.

Just my theory but I can see having more thermal issues with a 4.5 than a 3.5.

A 3.5 has enough rip that at most carpet tracks that you have to roll into the throttle coming off and lift early going into the corners. The 4.5 is a little under powered so to compensate you end up adding more gear and driving in deeper to try and keep up. This would likely creating more heat in the ESC causing the shut down issues.

Ureka!!! I need more motor. thanks guys.

You can never have enough motor!

I have had a 4.5 do shut down and cause the speedo to get very hot. I think it was because I had the bonded rotor in it instead of a sintered rotor.

I have never had this happen with a 3.5 though just a 4.5 with the bonded rotor.


Jason

I keep hearing how much rip and speed a 3.5 has. I have heard from a couple oval racers this is not the case vs say a 6 turn.
I would like to get feedback on this.
I question this because tc guys are running 4.5 on 6 cell without complaints of it being too much motor, so why would a 3.5 on 4 cell oval be out of control?

Thanks

so why would a 3.5 on 4 cell oval be out of control?

Its mostly because they drive much different than a brushed motor does. When you lift they dont slow down and it also has the tendancy to spin the tires much easier when you get on the throttle. The chassis setup is definately a little bit different than with a brushed motor. I know Monti/Kevin, John and the guys at World of Hobbies(cincy) ran a lap+ faster with the brushless motors last year over the brushed once they got it down.

Speaking from First hand experience, and Ulbrick can voice on this one..... The 3.5 vs 6/7 turn's scenario, is the fact that the brushless is way more efficient....The brushed motors would do the normal, "Fall Off" at the end of the run, and Dump...Where the Brushless motors would come off with 20-30 seconds of runtime...The last race we where all at, as horrible as all our cars were from lack of Traction/Bite there wasn't a single one of us that would have run a car like we did at a National event, but at that point, I think the Brushless had a better advantage at the end...Say at the snowbirds, I think, if you get your gearing right to the point you can almost dump, and the car set-up as best you can with the brushless, you'd already be a lap or 2 down by the end of the race if you were running a brushed motor......My .02

Hey Gary, They Have Said That The Past Two Weeks In A Row. But If You Look At It This Way, Every Class Is 3 Laps Off Last Years Record At Greenville Right Now. Including Andy Mac Running 66 Laps With A 3.5 To Him Running 69 Laps Last Year With A Brushed Motor. He Looked Even Faster With It This Past Weekend.

The 3.5 is by far my favorite motor. I have run it on a short carpet track running 3 second laps to a Velodrome turning 8.9's at 65+. The biggest rip I have ever had.

I ran a 0.98 and it was awesome on the small carpet track. I put in the big rotor and ran a 1.15 to 1.20. I thought the bigger rotor made it a little easier to drive on that small of a track.

I had to run the Spektrum voltage cap on the receiver to take care of a radio problem, but other than that, no issues.

Thanks for the tips guys.