30.5 OBR Prostock

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, and others.
B

brokestroke

Well-Known Member
Messages
203
Reaction score
219
Pretty simple question. I have a 30.5 OBR Prostock, billet case, 5.5hp(?) What exactly is a Prostock motor and what has been done to it to make it such?

Thanks
 
A model racing engine needs to be ported with 3 things in mind. Torque and temperature over time and fuel economy.
The more expensive engines don't take these factors into account due to the fact that they are strictly bashing engines. As amazing they would be on the track, they wouldn't last a full race.
 
...
Troopermaniac said:
A model racing engine needs to be ported with 3 things in mind. Torque and temperature over time and fuel economy.
The more expensive engines don't take these factors into account due to the fact that they are strictly bashing engines. As amazing they would be on the track, they wouldn't last a full race.
Click to expand...
Good deal, going to keep it around. Solid runner and would like to find a track for it. Think the previous owner raced it based on how the car was setup when I got it.
 
I have to say I'm perplexed at your statement @Troopermaniac , how is it a air cooled harley engine can go 100k miles but a "model" engine cannot go a full race? The concept of an engine needs to work in the real world and if it does congrats you just made a functional object called an engine. Yes you can slap cheap metal together and make it run but it won't last and that's seen with the clone engines but for an obr I think they use better metals so they don't kick the bucket on the first heat. And really the 3rd thing in mind is fuel economy? If I run through a gallon of fuel on a bash outing I'd be ok with that. Hell I'd be happy with better fuel economy on my raptor but I didn't buy it to get fuel range a Honda does.
 
Rep732 said:
I have to say I'm perplexed at your statement @Troopermaniac , how is it a air cooled harley engine can go 100k miles but a "model" engine cannot go a full race? The concept of an engine needs to work in the real world and if it does congrats you just made a functional object called an engine. Yes you can slap cheap metal together and make it run but it won't last and that's seen with the clone engines but for an obr I think they use better metals so they don't kick the bucket on the first heat. And really the 3rd thing in mind is fuel economy? If I run through a gallon of fuel on a bash outing I'd be ok with that. Hell I'd be happy with better fuel economy on my raptor but I didn't buy it to get fuel range a Honda does.
Click to expand...
Fuel economy likely applies in heat racing where fuel tanks have a max size.
 
The engine description on OBR's website:

PROSTOCK - An affordable/mild version of a full mod. The PROSTOCK line has replaced the Race Ported line. The PROSTOCK engines produce more power than the race ports and are more economical. To keep costs down, we focused our time tuning this engine to the areas that would yield the most power possible while maintaining reliability and ease of use. At OBR, we do not believe in stacking or using thick cylinder gaskets. We always machine and reshape the combustion chamber on our stroked engines. To help with reliability, we also relieve the piston. Piston reliefs help reduce the chances of the piston seizing on the exhaust side of the cylinder when running lean or hot. We were the first in this industry to do the piston relief several years ago. Being that this line is a budget/starter engine, we tuned it to run well with any exhaust. We kept in mind that you may not have a pipe. We have seen great performance with everything from an HPI can exhaust to a pipe. If upgrading to a pipe, we recommend the Jetpro Boss. For those of you that are new to ported engines, we shot for ease of use. This engine is very easy to start and to tune the carb. We have left the porting open on this engine. At any time, you may send the engine in to us to be upgraded to a full mod or a full mod long rod.
 
So trying to get this straight. It goes...

Race Port
Pro Stock
Full Mod

The differences in the 3 are based on how they are ported?
 
Back
Top