Piston and HP gains

[BigVince]

Okay... here's the scenario.

On an 04 i'm running the rossier exhaust, HRC kit with cam, i got the UNI airfilter. Now it's time to add a piston.

What kind of HP gains am i realistically looking at if i slap in a JE 13.1 or a HH 12.25 piston. I know how you guys feel about VCP.. but please be objective. I'm not involved in all that BS. I just want to know facts.

Also... since i got your attention... if i added a vortex rev box... what if any further hp gains am i looking at.

Thanks again.. and please be objective.

[chad502ex]

it doesn't matter if the HH is not supported and being made anymore- now does it?

[BigVince]

well if its not being made anymore i would say that it does matter. I was not aware of that fact.. if that is a fact. I don't know. I got an email from a local shop yesterday that said he had some comming in. However, that still doesn't answer my question. The question still applies to the JE13.1 or the Rossier 11.71 or a similar piston.

[iceracer65]

i put a wiseco 11.5:1 in mine.

i noticed a sweet gain in throttle response as well as throughout the powerband.

[BigVince]

do you run race gas with that piston or is 91 doing the trick. can you specualate on HP gains or top end speed gains?

[chad502ex]

for every point in static compression increase, generally, it is a ~3% gain in hp depending on dynamic compression via cam overlap.

Back to the HH not being supported or made thing. This is what I was told by some HH distributors and heard through the grapevine from Matt and Vince of VCP. These "rumors" may or may not be true.

[kgbg]

HH pistons are still being made and supported.


I have seen some great gains ( right at 4 hp and 2 ft lbs Dyno Proven same day) with a 12.25 HH. I even installed KW springs which rob a slight amount of power, so take that into account. The bike was already running ideal and had HC S2, intake and a PC, Dyna, before the runs.

http://www.hendersonphotography.com/dynohh12.25.jpg
Hosted at the ORG, and Hendyphotos bike.
EDIT: I forgot this was not the same day, that was a different bike, it was a day apart, but that does not matter = same Dyno.

[BigVince]

Thank you.

[iceracer65]

i run pump gas exclusively, even when i raced all summer. top speed was the same (gearing hadnt changed), i havent dynoed it yet but in order for me to feel the power i would have to say at leas a couple of HP.


chad: give an example of "1 point" of static compression.

[chad502ex]

1 point of static compression is:

from 12:1 to 13:1 static compression being worth ~3% gain

[OKTRX450R]

Originally posted by BigVince
Okay... here's the scenario.

On an 04 i'm running the rossier exhaust, HRC kit with cam, i got the UNI airfilter. Now it's time to add a piston.

What kind of HP gains am i realistically looking at if i slap in a JE 13.1 or a HH 12.25 piston. I know how you guys feel about VCP.. but please be objective. I'm not involved in all that BS. I just want to know facts.

Also... since i got your attention... if i added a vortex rev box... what if any further hp gains am i looking at.

Thanks again.. and please be objective.

BigVince, I run the HH 12.25 and the HRC cam. I experienced an amazing gain in power and I run on 91 pump gas with no problems. As I understand it the design of the HH 12.25 is supposed to equal the power of other manufacturers 13.1 designs. Also, as I understand you can run pump gas with the HCII cam too.

I have no ownership experience with other pistons or cams. But, I have ridden several other builds and received many compliments on mine by the other owners...

[skaydogg]

I HAVE A 06 TRX 450ER AND IT HAS THE CRF 450R MOTOR IN IT FROM FACTORY,THE COMPRESSION IS 12:1 AND I HAVE THE HRC KIT IN IT,THE DEALER SHOW ME THE PAPER IT HAS 50HP STOCK AND THE HRC KIT ADDS 15 HP,SO I HAVE 65 HP, AT LEAST THAT THEY TOLD ME.IT RIPS!

[OKTRX450R]

Originally posted by skaydogg
I HAVE A 06 TRX 450ER AND IT HAS THE CRF 450R MOTOR IN IT FROM FACTORY,THE COMPRESSION IS 12:1 AND I HAVE THE HRC KIT IN IT,THE DEALER SHOW ME THE PAPER IT HAS 50HP STOCK AND THE HRC KIT ADDS 15 HP,SO I HAVE 65 HP, AT LEAST THAT THEY TOLD ME.IT RIPS!

I think the 50HP on the dealer paper is at the crank...also, where did you find the HP gains on the HRC kit at?

[AceLtz]

Originally posted by skaydogg
I HAVE A 06 TRX 450ER AND IT HAS THE CRF 450R MOTOR IN IT FROM FACTORY,THE COMPRESSION IS 12:1 AND I HAVE THE HRC KIT IN IT,THE DEALER SHOW ME THE PAPER IT HAS 50HP STOCK AND THE HRC KIT ADDS 15 HP,SO I HAVE 65 HP, AT LEAST THAT THEY TOLD ME.IT RIPS!

50 hp was measured at the crank, not at the wheel. theres a big difference there. also the Hrc kit does not add anywhere close to 15hp.

From what people say about the HH they kick ***. bumping up the stock compression to 12:1 and being that the HH is a great piston youll notice a good power increase.

[BigVince]

Thanks to all who commented.