Starters--HP, KW, Torque, foot lbs, PMGR & OSGR

[Bihili]

So I needed a starter for my BB. I did my normal research on the subject and found it difficult to compare.
Some companies want to use KW, others use horse power (HP). They also round up their actual HP
Very few use foot lbs of torque.
There is the Delco design, the Hitachi design and Nippon design.
The PMGR, permanent magnet gear reduction starters were the hardest to compare.
Some use smaller HP motors with a higher gear reduction.
I guess the smaller motor with a larger gear reduction draws less current???
Standard gear reduction seem to be 3:75 then it went to 4.0 then 4.4 then 6.0
The OSGR, offset gear reduction still uses copper coils but comes in different gear reductions.
They all market how much compression they could handle but most lacked details.

In the end I bought one based upon the 180 lbs of torque it could deliver.
I didn't know this was going to be a complicated decision.

[chevynut]

Yeah it's like a lot of transmission places wanting to specify horsepower ratings. They're pretty meaningless for that. Torque is what they should be specifying, and I noticed Tremec does that. Same with rearends.

But for a starter, HP does make sense. HP is torque x RPM. So you want torque, but you also want it to turn over at a decent RPM. You don't want a high torque starter that barely turns your engine over at 1 RPM. :) Different gear reductions will increase or decrease torque, but HP will stay the same. The HP rating should be the rating of the motor.

HP is easy to change to KW. 1HP = .746 kilowatts.

[Rick_L]

It's kind of tricky to evaluate either torque or horsepower on a starter without knowing how fast the output gear turns. Even that is deceiving. Ever notice how fast a direct drive starter spins when it's not loaded?

Gear drive, permanent magnet is the best stuff these days.

Hope your choice turns out for you.

Curious, what were your other choices?

[Bihili]

Curious, what were your other choices?

Rick, I probably could have gone with with a re-manufactured Delco from Mexico for $40 bucks and it would have been fine for many years.
Not wanting to get criticized, I'll just say with 16 degrees basic timing for the small blower I need more torque in case my ignition controller retard does not work.