# Honda GX200 6.5HP vs 5.5HP???



## ChrisJ (Nov 27, 2014)

I have an older GX200 that says "6.5" right on the recoil cover. I also recall literature that stated 6.5HP.

Honda's current lineup shows the GX200 being rated 5.5HP.

Did something change causing the more recent engines to drop 1 HP such as emissions? Or were older Honda engines rated gross rather than net?



I'm also curious about this because the Predator / LCT engines claim 6.5HP on their similar sized engine.


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## 43128 (Feb 14, 2014)

The predators definitely make at least 7hp out of the box, more with some carb tweaking, same thing for the Honda gx200 engines. I don't work much with the gx160s and gx140s anymore.


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## Snapper 524 (Dec 10, 2013)

Some info on hp ratings.

http://www.smallenginewarehouse.com/Changes in Small Engine Horsepower Ratings.pdf


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## ChrisJ (Nov 27, 2014)

43128 said:


> The predators definitely make at least 7hp out of the box, more with some carb tweaking, same thing for the Honda gx200 engines. I don't work much with the gx160s and gx140s anymore.



Interesting being the Predator 6.5, at least according to it's peak torque spec, makes less power than a Honda GX200 which is now rated 5.5HP as per the new standard.

Sounds to me like Predator / LCT is using a gross spec while Honda is using net.

8.1ft-lb, even assuming that peak is still there at 3800 rpm is still only 5.8HP. 5.5HP at 3600.


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## 43128 (Feb 14, 2014)

i wouldnt trust a chart that lists the gx340 and gx390 as having the same torque


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## GustoGuy (Nov 19, 2012)

ChrisJ said:


> Interesting being the Predator 6.5, at least according to it's peak torque spec, makes less power than a Honda GX200 which is now rated 5.5HP as per the new standard.
> 
> Sounds to me like Predator / LCT is using a gross spec while Honda is using net.
> 
> 8.1ft-lb, even assuming that peak is still there at 3800 rpm is still only 5.8HP. 5.5HP at 3600.


The Predator 212cc engine makes way more the 5.5hp. I have 3 of them and one is on a 26 inch repowered Montgomery Ward ( Gilson ) 8 / 26 has plenty of power and it has as much power or more then the old Briggs 8hp that was puffing blue smoke every once in awhile. NR racing Dyno a Predator 212cc engine with a low restriction K&N style air filter and richer jetting was making just over 9hp out of the box according to the dyno. I hogged out airbox on the Predator 212cc on the mini bike and jetted richer and it had quite a bit more snap off the bottom and became a wheelie machine and I fixed it by attaching 12 lbs of plate steel total with 4 lbs down low on the frame and 8lbs mounted over the front wheel on the number bracket.


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## Snapper 524 (Dec 10, 2013)

43128 said:


> i wouldnt trust a chart that lists the gx340 and gx390 as having the same torque


I just went to honda's website and surprisingly the engines are listed as having the same torque.

Honda Engines | Small Engine Models, Manuals, Parts, & Resources | Official Site


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## ChrisJ (Nov 27, 2014)

GustoGuy said:


> The Predator 212cc engine makes way more the 5.5hp. I have 3 of them and one is on a 26 inch repowered Montgomery Ward ( Gilson ) 8 / 26 has plenty of power and it has as much power or more then the old Briggs 8hp that was puffing blue smoke every once in awhile. NR racing Dyno a Predator 212cc engine with a low restriction K&N style air filter and richer jetting was making just over 9hp out of the box according to the dyno. I hogged out airbox on the Predator 212cc on the mini bike and jetted richer and it had quite a bit more snap off the bottom and became a wheelie machine and I fixed it by attaching 12 lbs of plate steel total with 4 lbs down low on the frame and 8lbs mounted over the front wheel on the number bracket.


How is "with a low restriction K&N style air filter and richer jetting" the same as "out of the box" ??? 



I'm also not surprised it made more power than a worn out B&S engine that obviously had serious problems.


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## ChrisJ (Nov 27, 2014)

43128 said:


> i wouldnt trust a chart that lists the gx340 and gx390 as having the same torque





Snapper 524 said:


> I just went to honda's website and surprisingly the engines are listed as having the same torque.
> 
> Honda Engines | Small Engine Models, Manuals, Parts, & Resources | Official Site



The peak torque is the same on both.
The reason the GX390 makes more power is it produces more torque at a higher rpm, but it's peak torque is still the same.

My point was an engine like the Predator that claims it's peak torque is 8.1 ft-lb CANNOT make more than 5.8HP at 3800rpm. The most common formula to figure out horsepower on an engine is torque X rpm / 5252.

Here are the power curves for GX340 and GX390. From what I see, it seems like the GX390 just breaths better than the 340 for whatever reason, bigger valves maybe? Strange it doesn't make more power at a lower rpm too, but it is what it is.


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## nZone (Feb 19, 2015)

Looking at GXV340, the displacement is 337cm^3.


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## GustoGuy (Nov 19, 2012)

ChrisJ said:


> How is "with a low restriction K&N style air filter and richer jetting" the same as "out of the box" ???
> 
> 
> 
> I'm also not surprised it made more power than a worn out B&S engine that obviously had serious problems.


NR racing was trying to see what the base Hp was without touching any of the internals of the engine. The stock air box and filter are quite restrictive and there is power to be made by allowing the engine to breath better.


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