# 3.5 vs 5 hp and dana 8.9 **URL:** \ **Category:** GEM Forum\ **Created:** [November 19, 2015, 7:49am UTC](https://community.electricforum.com/t/3-5-vs-5-hp-and-dana-8-9/5594 "2015-11-19T07:49:38Z")\ **Posts on this page:** 18\ **Page:** 1
**Author:** ![SCOUT202](https://avatars.discourse-cdn.com/v4/letter/s/65b543/32.png) [@SCOUT202](https://community.electricforum.com/u/SCOUT202)\ **Post date:** [November 19, 2015, 7:49am UTC](https://community.electricforum.com/t/3-5-vs-5-hp-and-dana-8-9/5594/1 "2015-11-19T07:49:38Z")
hey guys I just picked up 2 motors one is a stock 3.5 and the other is a 5hp is there any benefit to the 5 hp? speed torque? the 5hp has an extra black plug coming from the brush area of motor with oblong plug What is this for`? Also the 5hp spins at approx 500 less rpm than the 3.5 I use my truck version for utility use and although speed is fun torque often is needed more than speed I am currently using a 8.9 gear and think I’d be better off with the 10,9 or 12 how much speed will a sacrifice using the lower gear ratios ---
**Author:** ![Old\_Houseboater](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/old_houseboater/32/544_2.png) [@Old\_Houseboater](https://community.electricforum.com/u/Old_Houseboater)\ **Post date:** [November 19, 2015, 8:19am UTC](https://community.electricforum.com/t/3-5-vs-5-hp-and-dana-8-9/5594/2 "2015-11-19T08:19:51Z")
5HP will give more torque. Speed is a function of the programming. Gear ratio - Tire diameter etc. Speed is limited by how fast you can turn the motor without having it “Grenade” 3.5 motor is rated for 4500 Rpm 5 motor is rated for 4100 Both motors will live at 5000 Rpm Since you have a truck you would be happier with a 10.35 or a 12.44 If your on flat ground go with the 10.35 if in hilly go with a 12,44. You have the 5HP long motor which is from the later model carts. the extra wires are for a thermal sensor. You don’t have to use it List your tire diameter and gear ratio and I wll tell you your Motor RPM at 25, 30 and 40MPH Rodney ---
**Author:** ![SCOUT202](https://avatars.discourse-cdn.com/v4/letter/s/65b543/32.png) [@SCOUT202](https://community.electricforum.com/u/SCOUT202)\ **Post date:** [November 19, 2015, 9:59am UTC](https://community.electricforum.com/t/3-5-vs-5-hp-and-dana-8-9/5594/3 "2015-11-19T09:59:56Z")
[quote=OLD HOUSEBOATER;27798]5HP will give more torque. Speed is a function of the programming. Gear ratio - Tire diameter etc. Speed is limited by how fast you can turn the motor without having it “Grenade” 3.5 motor is rated for 4500 Rpm 5 motor is rated for 4100 Both motors will live at 5000 Rpm Since you have a truck you would be happier with a 10.35 or a 12.44 If your on flat ground go with the 10.35 if in hilly go with a 12,44. You have the 5HP long motor which is from the later model carts. the extra wires are for a thermal sensor. You don’t have to use it List your tire diameter and gear ratio and I wll tell you your Motor RPM at 25, 30 and 40MPH Rodney[/quote] 14x23 is tire size ---
**Author:** ![Old\_Houseboater](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/old_houseboater/32/544_2.png) [@Old\_Houseboater](https://community.electricforum.com/u/Old_Houseboater)\ **Post date:** [November 19, 2015, 11:22am UTC](https://community.electricforum.com/t/3-5-vs-5-hp-and-dana-8-9/5594/4 "2015-11-19T11:22:17Z")
…25MPH … 30MPH 8.9 - …3253 …3904 10.35 - …3783 …4540 12,44 - …4547 … 5456 If your on flat ground you have the long 5 which is pretty strong. Pop it on your 8.9 gear box., Set function 1 (MPH scaling) to 23 - Set function 7 (min field current) to 62 - Set function 20 (MPH limit) to 32 The cart should do pretty with those settings, if you easy foot it when you have 4 aboard. , Let us know how it works out Rodney ---
**Author:** ![Inwo](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/inwo/32/1067_2.png) [@Inwo](https://community.electricforum.com/u/Inwo)\ **Post date:** [November 19, 2015, 11:38am UTC](https://community.electricforum.com/t/3-5-vs-5-hp-and-dana-8-9/5594/5 "2015-11-19T11:38:09Z")
I already had this typed out before it was answered, so I’ll post it for future reference.:o 23"D X pi = 72.26" circ. = 6.2’ cir 5280ft/mile / 6.02circ= 877rp mile motor 8.9 times as fast = 7805 motor rotations per hour 25mph = 195,133 motor rotations per 25 miles (in 1 hour) 195,133 / 60 = 3,252 rotations per minute (RPM) ---
**Author:** ![Old\_Houseboater](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/old_houseboater/32/544_2.png) [@Old\_Houseboater](https://community.electricforum.com/u/Old_Houseboater)\ **Post date:** [November 19, 2015, 11:41am UTC](https://community.electricforum.com/t/3-5-vs-5-hp-and-dana-8-9/5594/6 "2015-11-19T11:41:18Z")
Dave I sent you my spread sheet by email All you have to do is enter the tire diameter Rodney ---
**Author:** ![Inwo](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/inwo/32/1067_2.png) [@Inwo](https://community.electricforum.com/u/Inwo)\ **Post date:** [November 19, 2015, 12:32pm UTC](https://community.electricforum.com/t/3-5-vs-5-hp-and-dana-8-9/5594/7 "2015-11-19T12:32:42Z")
Thank you, Now what will I do to stay awake? 😃 ---
**Author:** ![LithiumGods](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/lithiumgods/32/672_2.png) [@LithiumGods](https://community.electricforum.com/u/LithiumGods)\ **Post date:** [November 19, 2015, 8:15pm UTC](https://community.electricforum.com/t/3-5-vs-5-hp-and-dana-8-9/5594/8 "2015-11-19T20:15:56Z")
if u decide to sell the 3.5 hp motor , please let me know. ---
**Author:** ![Old\_Houseboater](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/old_houseboater/32/544_2.png) [@Old\_Houseboater](https://community.electricforum.com/u/Old_Houseboater)\ **Post date:** [November 19, 2015, 8:55pm UTC](https://community.electricforum.com/t/3-5-vs-5-hp-and-dana-8-9/5594/9 "2015-11-19T20:55:34Z")
I’ve got a short 5 and a 7 surplus ---
**Author:** ![LithiumGods](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/lithiumgods/32/672_2.png) [@LithiumGods](https://community.electricforum.com/u/LithiumGods)\ **Post date:** [November 20, 2015, 6:27am UTC](https://community.electricforum.com/t/3-5-vs-5-hp-and-dana-8-9/5594/10 "2015-11-20T06:27:15Z")
> [@OLD HOUSEBOATER;27818](#): > > I’ve got a short 5 and a 7 surplus Rodney, what are “short 5” motors ? did they make different length 5’s ? ---
**Author:** ![Old\_Houseboater](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/old_houseboater/32/544_2.png) [@Old\_Houseboater](https://community.electricforum.com/u/Old_Houseboater)\ **Post date:** [November 20, 2015, 7:37am UTC](https://community.electricforum.com/t/3-5-vs-5-hp-and-dana-8-9/5594/11 "2015-11-20T07:37:32Z")
Short 5 was used thru 2004. Long 5 starting in 2005 - has overheat sensor. ---
**Author:** ![SCOUT202](https://avatars.discourse-cdn.com/v4/letter/s/65b543/32.png) [@SCOUT202](https://community.electricforum.com/u/SCOUT202)\ **Post date:** [November 21, 2015, 6:46am UTC](https://community.electricforum.com/t/3-5-vs-5-hp-and-dana-8-9/5594/12 "2015-11-21T06:46:22Z")
[quote=SCOUT202;27797]hey guys I just picked up 2 motors one is a stock 3.5 and the other is a 5hp is there any benefit to the 5 hp? speed torque? the 5hp has an extra black plug coming from the brush area of motor with oblong plug What is this for`? Also the 5hp spins at approx 500 less rpm than the 3.5 I use my truck version for utility use and although speed is fun torque often is needed more than speed I am currently using a 8.9 gear and think I’d be better off with the 10,9 or 12 how much speed will a sacrifice using the lower gear ratios[/quote] Rodney, I received my used controller from Arizona and installed it i replaced my 3.5 with the other 3.5 both ohmed out fine. I have 6 brand new battery’s i tested voltage into the controller it is 75.9 the large contactor is engaging. When pedal is depressed motor whines but no rotation. tried a different motor with same result\> I’m stumped any suggestions? ---
**Author:** ![Old\_Houseboater](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/old_houseboater/32/544_2.png) [@Old\_Houseboater](https://community.electricforum.com/u/Old_Houseboater)\ **Post date:** [November 21, 2015, 6:59am UTC](https://community.electricforum.com/t/3-5-vs-5-hp-and-dana-8-9/5594/13 "2015-11-21T06:59:27Z")
Bad controller ---
**Author:** ![SCOUT202](https://avatars.discourse-cdn.com/v4/letter/s/65b543/32.png) [@SCOUT202](https://community.electricforum.com/u/SCOUT202)\ **Post date:** [November 21, 2015, 7:04am UTC](https://community.electricforum.com/t/3-5-vs-5-hp-and-dana-8-9/5594/14 "2015-11-21T07:04:25Z")
> [@OLD HOUSEBOATER;27852](#): > > Bad controller are there any voltage readings out of bottom of controller when pedal depressed? should voltage start low and progress to high at full throtle? ---
**Author:** ![Old\_Houseboater](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/old_houseboater/32/544_2.png) [@Old\_Houseboater](https://community.electricforum.com/u/Old_Houseboater)\ **Post date:** [November 21, 2015, 8:33am UTC](https://community.electricforum.com/t/3-5-vs-5-hp-and-dana-8-9/5594/15 "2015-11-21T08:33:52Z")
Make sure you have field wires on field and armature wires on armature. As the field current changes the armature current increases. ---
**Author:** ![SCOUT202](https://avatars.discourse-cdn.com/v4/letter/s/65b543/32.png) [@SCOUT202](https://community.electricforum.com/u/SCOUT202)\ **Post date:** [November 21, 2015, 11:37am UTC](https://community.electricforum.com/t/3-5-vs-5-hp-and-dana-8-9/5594/16 "2015-11-21T11:37:15Z")
did some voltage checks at motor key on or off readings are the same A-1 to ground 40.0 volts A-2 to ground 40.0 volts F-1 to ground 33.6 volts F-2 to ground 33.7 volts Key on forward gear pedal depressed engages large relay and motor does nothing whine coming from controller. ---
**Author:** ![Inwo](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/inwo/32/1067_2.png) [@Inwo](https://community.electricforum.com/u/Inwo)\ **Post date:** [November 21, 2015, 12:02pm UTC](https://community.electricforum.com/t/3-5-vs-5-hp-and-dana-8-9/5594/17 "2015-11-21T12:02:02Z")
The 72v supply is not grounded, so checks to ground aren’t helpful. ---
**Author:** ![Inwo](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/inwo/32/1067_2.png) [@Inwo](https://community.electricforum.com/u/Inwo)\ **Post date:** [November 21, 2015, 12:04pm UTC](https://community.electricforum.com/t/3-5-vs-5-hp-and-dana-8-9/5594/18 "2015-11-21T12:04:16Z")
OH would know more, but an analog voltmeter should read F and A voltages… A to A and F to F.