Honda Grom banner
1 - 20 of 39 Posts

·
Premium Member
Joined
·
1,753 Posts
Discussion Starter · #1 ·
I put The Great White Grom in the bike show at the grand opening of Roseville Honda. BHP Motorsports had their dyno trailer there, so I threw the Grom on it to see what was what.

The dealership was raffling off a Grom that day so tons of people were swarming all over my Grom and of course many had never seen such a thing.

They were not able to get an accurate AFR reading because the probe would not go in to my exhaust far enough (that never stopped my alien abductors, but that's a different discussion thread...). He wasn't going to charge me but I gave him $20 anyway. I will put a different pipe on there and take it to his shop and hell do the full test for free.

Transport Vehicle Ceiling Room Tire


The bike as tested was stock except for K&N R100 intake (with AT sensor mounted in the cone), Custom made Cobra exhaust, and 14t counter sprocket.

So it looks like 11.16 BHP @7422.2 RPM - Max Torque 8.24 Ft/lb @ 6302.1 RPM. Power started to fade shortly after 7422 RPMs.

Blue Glitter Text Purple Galaxy

Text Line Font Number Parallel
 

·
Registered
Joined
·
98 Posts
Think you got maybe a HP or two from the free flow air filter and exhaust? And did you win another Grom or what!?
 

·
Registered
Joined
·
4,049 Posts
Seems like a pretty good HP # at the rear wheel. Thanks for posting.
 

·
Registered
Joined
·
186 Posts
I still can't believe they were giving away a grom....that would have been a kick ass to win.
 

·
Premium Member
Joined
·
1,753 Posts
Discussion Starter · #10 ·
I think the 14t probably had something to do with the torque bump.


I did not win the Grom raffle but I stuck around all day waiting for the name call, what the heck.... The show featured a few nice bikes, including the two best bikes Honda ever made guarding the entrance:

Land vehicle Vehicle Motorcycle Race track Car
 

·
Registered
Joined
·
111 Posts
I'd be happy with that considering just an exhaust, filter and sprocket change. Nice one!
I'll stop short of saying ~1.5hp gain from an exhaust + air filter change ain't gonna happen...just highly unlikely. There's some variation of real world output between individual engines - right from the assembly line, dyno accuracy (especially with small displacement) and, I suspect that OEM output numbers are more conservative than in the past. That said, this is one very healthy stocker, imho.

Sprocket changes don't change hp output. Measured at the crank, as is done with most other engines, hp is unaffected by gearing. What gearing changes can affect is how much power reaches the ground. An over-geared engine will be unable to reach the rpm at which peak hp occurs...and that will definitely show up, in a big way, on the dyno.

As for the power falling off above its peak, what else would you expect? No offense but, that's what defines peak hp; the point at which hp stops increasing and begins falling off. Most small Hondas of this basic type make usable power at least 1000-1500rpm past peak...then the graph curve resembles a cliff.
 

·
Premium Member
Joined
·
1,753 Posts
Discussion Starter · #12 ·
I'll stop short of saying ~1.5hp gain from an exhaust + air filter change ain't gonna happen...just highly unlikely. There's some variation of real world output between individual engines - right from the assembly line, dyno accuracy (especially with small displacement) and, I suspect that OEM output numbers are more conservative than in the past. That said, this is one very healthy stocker, imho.
......
I told you guys the red ones are faster. This one came from the factory as red.

-

I have no idea if anything I did to the bike effected peak power or not (other than buying a red one). This was just something to do while waiting for the raffle winner to be called. This dyno run is now my baseline for when I get my EJK controller.
 

·
Registered
Joined
·
4,049 Posts
Would be nice to see some real controlled dump runs on our groms. Stock then with a pipe them with a pipe and intake. All on the same day same bike same dump.

SS has a strong Grom but I'd like to know what it pulled before those mods.


Sent from my iPhone using HondaGrom.net
 
  • Like
Reactions: EdPrez
1 - 20 of 39 Posts
Top