Super!!! fast buggy setup .....

[Guerilla]

I think ive chose a setup, what do you think of the following

Lehner LMT 2250/10
Flightpower 4s 5000mAh X2 in 8s configeration
MGM 24/160

On 8s the motor will be running 35,046 rpm.

[aqwut]

that would be fast... if you're not worried about the weight.. then it's all good...

[glassdoctor]

If the goal is 70+mph.... IMO you should get a little higher peak rpm than 35K.

It's just a matter of gearing... gear it high enough and it will get there.

But a higher revving setup would not require as a crazy a gear ratio to hit 70+

For a basic all purpose setup I do like the 35K number though. And you CAN just gear it way up to fly, and still be able to have a good "normal" setup if you gear it for racing etc.

[glassdoctor]

Here's what I'm thinking...

Example: My buggy is geared 18/46 (8.4:1 final drive ratio) which is pretty tall.. larger pinions would probably need to be custom made, and 44T is the smallest spur I know of that will work easy. I could gear it higher but not with commonly used parts.

With this 8.4:1 ratio as an example... 70mph = 42K rpm... 80mph = 48K rpm

That's an estimate based on the 43mph I got yesterday on my "26K rpm" setup.

The same #'s say a 35K setup would run 58mph with the 8.4:1 gearing. And to go faster:

80mph = 6:1 ratio (25/46 pinion/spur)

That may actually be a good setup if you can get some big pinions. Anyone know where to get some like that?.... 20-25T range?

Just a rough estimate... I havent' even checked it against my old numbers I have recorded etc or BrianG's calc...

[Guerilla]

Any one know if mike could make me some custom pinions in the 20-30 tooth range.

So what turn 2250 does every one think i should go with and an estimated speed. I was thinking 10 or the 8 but will the 8 be a little high on the rpms? any idea if im going to get 10mins plus runtime on a 5000mAh 8s setup

[glassdoctor]

Originally Posted by Guerilla

any idea if im going to get 10mins plus runtime on a 5000mAh 8s setup

This type setup is not something I have done or even seen done... but an 8s setup should have crazy runtimes. (min. per mah)

I don't see how it could NOT be longer run times than our "normal" 4s setups per mah. I would get +20 minutes track time on 5000 packs... I would guess your 8s would get 20 min at least???

Probably 30+ IMO :027:

Again... just a gut feeling... but the runtime will be impressive.

[Guerilla]

8 or 10 turn ? will 8s be pushing the 8turn to far ?

[glassdoctor]

I don't know the kv of the 8 turn.

The 2250/10 is 1184kv. 8s lipo... (assuming a 3.5v per cell under load) would be 28V, which is only 33K rpm. I can't imagine the 2250/8 would be out of range at 28V... what's the kv??

here's an interesting quote from a post I found at rczone... "I don't know if a car could really go much faster with that same power setup. That boat was actually flying over the water with only the prop and rudder touching the water. This means it probably has less drag than a car at comparable speed. FYI-that was using a Lehner 2250/8 using a 32.170 schultze controller (32 cell, 170 amps continuous, water cooled) This setup spun the 2" prop at 47,500 rpm, producing over 3000 watts. Still, a car could probably go pretty fast on this setup, which would probably require a custom chassis, due to the fact that he was using 32 GP3300s, instead of the AA or smaller cells that the really fast cars sometimes use. "

[coolhandcountry]

If you can't choose between a 8 turn and 10 turn. Why not go 9 turn? The 9
turn is rated at 1315 kv. The 8 turn is rated at 1480. The 9 t will spin at 38k on 8s at 3.7v per cell. 2250 can for all above kvs.

[squeeforever]

Mike can make you a 24T pinion I know. He made one for Captain Harlock.

[Hayden]

Humm that’s a lot of power to push those speeds you will need a straight road or very flat footy field/golf course and steadily clime up the speed, I don’t know a lot about monster trucks running brushless but going on my touring car and aero experience that’s a lot of power you’ll have.