27.5 vs 30.5

  • Thread starter Thread starter Guest
  • Start date Start date
This site may earn a commission from merchant affiliate
links, including eBay, Amazon, and others.
G

Guest

Guest
I am looking for some advice here. I want to buy one of the OBR motors for my MT. They have a 30.5 rated at 7hp and a 27.5 rated at 7.5hp. :eek: these numbers seem to be about twice what other motors are rated at. Are they accurate? I sent them a msg asking why the smaller motor makes more hp. Do any of you run their motors? Does anyone know the difference between the 27 vs 30. There both 4 bolts but the 27 with more hp is cheaper. Is it just marketing. Maybe people expect the 30.5 to be more. Maybe the parts for the more common 27 are less expensive. Anyway it's not the cost I'm concerned about, I want the best motor. My mt is a heavy pig and is gaining weight with my new cage. As always any info is much appreciated. :D


Oh yeah, I hope Demons two speed can handle it. I am hoping to do both at the same time. I am trying to be extra good if Santa is watching,lol. :rolleyes:
 
It is a known fact that 27.2 motors can make more power than the 30.5cc I am no expert, but it has to do with the way the porting is able to be done.

OBR makes excellent motors and are well used in many large scales. You would be best to special order it for a Rampage, and have them install the CY fan housing already. Then, you won;t have to change it yourself or notch the chassis.
 
Rob, welcome back hope ya had fun. Thanks for the info. I already have a chrome CY cover on my stocker, that would right?

BTW can you send me a pm on the parts I emailed you on? Thanks again.
 
I heard back from OBR. They recommend the 30.5 for the rampage. They said the 27.5 can squeeze a little more hp from a little higher revs. They said the 30.5 has more torque. They said the extra torque would equal a faster rampage. Sounds like they know their $h!+ :)
 
Last edited:
RCDAD said:
I heard back from OBR. They recommend the 30.5 for the rampage. They said the 27.5 can squeeze a little more hp from a little higher revs. They said the 30.5 has more torque. They said the extra torque would equal a faster rampage. Sounds like they know their $h!+ :)
Click to expand...
Boy do they know have you seen some of there sick videos?????????? Man to awesome!!!!!!!
 
Go for that torque of the 30.5 and with a 2 speed that extra rpms out of the 27.5 wont matter anyway. If i had the coin i would definitely buy a ONB 30.5.
 
Yeah I know what ya mean about the coin. I also really would like a buggy but that's a whole another thread:rolleyes: I better finish one before I start another. I tend to have to many unfinished projects. Lol
 
On there Prostock engines the 30.5 makes more HP then the 27.2. Yes OBR does very good work and there customer service is all so very good. If you need a quick answer to a question you are better off calling them during business hours. Let us know how your Red Cat holds up with that much HP.
 
Back
Top