# Warp 9 Impulse RPM



## octagondd (Jan 27, 2010)

Hello all,
I have an Impulse 9 in my Honda CRX. All seems well at this point, but I looked at the Netgain site a little while ago and saw that they suggested gearing the car for between 1500 and 2500 RPMs. I am running between 3000-4000 RPMs at freeway speeds of 60 to 70 mph in 3rd gear. I am at this speed and RPM for roughly 15 minutes at a time. Am I doing damage or is this still the safe zone for long term wear and tear?

I sometimes move to 4th gear to lower the RPM a bit, but I have a large 2 mile hill on my route which I need to be in 3rd for.

Thanks,
Dave


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## octagondd (Jan 27, 2010)

octagondd said:


> Hello all,
> I have an Impulse 9 in my Honda CRX. All seems well at this point, but I looked at the Netgain site a little while ago and saw that they suggested gearing the car for between 1500 and 2500 RPMs. I am running between 3000-4000 RPMs at freeway speeds of 60 to 70 mph in 3rd gear. I am at this speed and RPM for roughly 15 minutes at a time. Am I doing damage or is this still the safe zone for long term wear and tear?
> 
> I sometimes move to 4th gear to lower the RPM a bit, but I have a large 2 mile hill on my route which I need to be in 3rd for.
> ...


Thread should be titled IMPULSE 9 RPM


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## major (Apr 4, 2008)

octagondd said:


> Hello all,
> I have an Impulse 9 in my Honda CRX. All seems well at this point, but I looked at the Netgain site a little while ago and saw that they suggested gearing the car for between 1500 and 2500 RPMs. I am running between 3000-4000 RPMs at freeway speeds of 60 to 70 mph in 3rd gear. I am at this speed and RPM for roughly 15 minutes at a time. Am I doing damage or is this still the safe zone for long term wear and tear?


Good question. I favor the higher RPM for such driving. It will provide much better motor cooling via the shaft mounted internal fan. Of course brushes and bearings wear faster at higher RPM but I doubt you'd notice increased service requirements in your case.


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## octagondd (Jan 27, 2010)

major said:


> Good question. I favor the higher RPM for such driving. It will provide much better motor cooling via the shaft mounted internal fan. Of course brushes and bearings wear faster at higher RPM but I doubt you'd notice increased service requirements in your case.


Thank you major. I feel a bit better now. I remember seeing something previously about running higher RPMs and the internal fan helping to cool. I thought as long as I am not running high amps and creating a lot of heat that way, I would be ok, but it helps to verify with others with experience.

I am running about 250 motor amps going up that hill for a minute and a half, but I doubt I am pushing the motor anywhere near its 180C temperature limit.


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## EVfun (Mar 14, 2010)

I run my Prestolite MTC down the freeway at 4500 rpm regularly and it's running at 5000 rpm when I'm going 70mph. More motor voltage means less motor current, because it takes about the same amount of power to go a given speed no matter what gear you choose.


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## dladd (Jun 1, 2011)

I questioned Netgain about this in 2012. Here was the email I received from them back then:
-----------------------

David,

Thank you for pointing me to the document. We have Gigabytes of information, and I have often heard people mention this 1500-2500 RPM limit and apparently we forgot to update it years ago! I have attached the section 4 version of the document that is correct and I have CC'd our web site administrator (Hunter) so that he can also update the online version.


You are correct that the motors prefer a higher RPM - typically around 1000 RPMs higher per gear than the original gas engine (rule of thumb). You want the lower Amps whenever it keeps the RPMs below around 4000 RPMs. The motors really need 2500-3500 to properly cool themselves..

George
George F. Hamstra 
NetGain Motors, Inc


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## octagondd (Jan 27, 2010)

dladd said:


> I questioned Netgain about this in 2012. Here was the email I received from them back then:
> -----------------------
> 
> David,
> ...


This is excellent news. I felt the performance and efficiency was much better in 3rd gear at 3500 than 4th at 2500 and this makes sense considering the voltage to the motor being higher which takes less current for the same power.

Now, if they would just update their website to remove that FAQ about RPM recommendations.


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