# I have to chose: 9 or 11?



## tido (Sep 20, 2011)

Today I visited a forklift repair shop and I found 2 interesting motors. The first one is a 9''diameter 17,75''long. The second one is a 11'' 17''.

My car is a Pontiac Fiero and it will be running 144V.

I though having a 11'' would be more efficient with the power I provide it but the 9'' would be more convenient to install as it is lighter.

Any thoughts?


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## Ziggythewiz (May 16, 2010)

Usually a 9 would be at least as efficient as an 11, it just doesn't have as much peak torque.


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## ddmcse (Oct 9, 2008)

how much lighter?
take them both you'll want one over the other for the next ev you do.


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## tido (Sep 20, 2011)

ddmcse said:


> how much lighter?
> take them both you'll want one over the other for the next ev you do.


I think I'll wait to have a new project in mind before buying the parts!

I couldn't weight them but I think it's something like 150 pounds to 220.


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## tido (Sep 20, 2011)

Ziggythewiz said:


> Usually a 9 would be at least as efficient as an 11, it just doesn't have as much peak torque.


Really? Well in that case I think the 9'' would be a better choice as I don't mind that much for my peak torque...


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## piotrsko (Dec 9, 2007)

AHHH the questions: which looks prettier and which is cheaper? if both are the same motor, then......

(yeah I know not really all that subjective)


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## tido (Sep 20, 2011)

I don't care about the 50$ price difference and the look... well the motor will be hidden by the battery boxes...


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## Duncan (Dec 8, 2008)

Hi Tido

The 11 inch will (probably) be limited to lower revs than the 9 inch

I have an 11 inch - because that is what the shop had - given a choice I would have gone for a 9
But that is for a 500Kg car

An 11 inch will be able to produce more power for longer than a 9 inch before it overheats


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## Yabert (Feb 7, 2010)

Ziggythewiz said:


> Usually a 9 would be at least as efficient as an 11, it just doesn't have as much peak torque.


And another important consideration about motor efficiency can be the motor construction.


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## DavidDymaxion (Dec 1, 2008)

Will the 11 inch even fit? Many FWD cars (yes, the Fiero is RWD but it has a FWD transaxle in the rear) don't have much room between the tranny input shaft and one of the axles.


Yabert said:


> And another important consideration about motor efficiency can be the motor construction.


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## tido (Sep 20, 2011)

DavidDymaxion said:


> Will the 11 inch even fit? Many FWD cars (yes, the Fiero is RWD but it has a FWD transaxle in the rear) don't have much room between the tranny input shaft and one of the axles.


Yes, the 11'' should fit. I found some fiero drivers using a 11''


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