fanmercer

I'm looking for the easiest way to find the RPM of a 540 motor. This way I'm hoping to tell if I'll get an actually increase in speed when I switch as opposed to a theoretical increase. What is the tool/method to test this?

raz54

Just because a motor might be listed with a high rpm rating does not mean it will make your car faster. For example I have a 19 X 2 Raven motor and a 15 X 1 havock motor (no rpm listed). The havock may be slightly faster in over all speed but the raven motor has a lot more torque and gets the truck moving a lot faster. It will do wheelies with the 19 X 2 but not with the 15 X 1 so there is a lot more to motor selection than rpm ratings. I would go with a 19 X 2-21 X 2 motor, lots'of low end torque and still good run times.

Flyojumper

To build on the previous post, some motors may be listed as say 38000rpm, but those numbers are almost always under no load on the dyno.
That particular motor that can achieve 38000rpm may have very poor torque between 30000-38000rpm and once you put it under load (in your car) it may only be able to reach an actual 28000rpm.
Another motor you discounted based on rpm may have a 35000rpm under no load rating but have a substantially higher torque until its rpm peak and may very well be able to spin in the car (under load) at 31000rpm, resulting in a higher speed than the first motor.
I really wish there was a partcular rating/measurement that could really give a precise comparison tool for top speed of each motor... Something like a "max rpm under Xoz load" (or whatever would be the industry standard of the average tranny's resistance on an average car weight)

fanmercer

Thanks. You guys really know your s***. That all being said, here is the pratical situation. I took the cheap but toqurey 540 out of my truck and replaced it with an old technigold-(yes, the avante ones), that I had lying around. The speed increased quite a bit, but still sufficent torque rated at 21000-(guessing 21 turns) rpm. This being said, what would be an inexpensive motor that is the next step up?

raz54

Every one has their favorite motor so you will get lots of recondations. I have had very good luck with the Orion Method 21x2 motor. It has lot's of low end torque and good top speed and very good run times and doesn't cost an arm and a leg.


http://www2.towerhobbies.com/cgi-bin...2&I=LXJBY9&P=K

leachy

Just wondering how you read the figures on a dynoed motor. Will that tell you how the motor will perform under load.

Regards
Leachy

raz54

From what I understand the dyno runs are with NO load so the rpms will be different once it's pushing the car. I go a lot by what others here are using as they have already tested them and know what's good.