HPV4 to HPV3???

[kbates20]

Just wondering if it is going to be that much more quiet...Just kinda bummed about have to go down on a pipe (and have to buy a new one) and change to vp MS98... A good loss of power to my class right? Any feedback appreciated...

[Guest]

Im not in favor or against any change since im not racing this class. The hpv-3 isnt even much quieter than the 4 pipe. i mean listen to the shifters and arnt the yamahas quite loud too?

Plus the rule said it would make it easier to transfer from tri-c and race with sdka but tri-c races both the 3 and 4 pipe. All you do to switch pipes is change the flex.

Just my 3 or 2 or 1 or 0 cents

[kbates20]

i agree, i rather have the power of the 4, its super easy to just change a pipe and flex, i think we should take a vote

[Jeff Shadoan]

Some answers to the questions/concerns:

Noise
When the noise levels were actually measured at Qualcomm, HPV-4 was a close second to Shifters. Luckily for SDKA, shifters and HPV were two classes where things could be done to lower the noise levels. HPV-3 may not be vastly quieter than HPV-4 but it is quieter. We (SDKA) need to make changes wherever possible to lower the levels for next season (sound carries and a fraction of a decibel makes a difference). I think everybody can imagine what the worst case scenario could be if no changes are made.
For Shifters we now require an air box plus a 14" exhaust silencer with a turn-down tip. The combination of these make a big difference in noise.

Loss of Power
The difference in lap times between HPV-3 and HPV-4 at Qualcomm is insignificant (minimal to none at all). Looking back at a couple races where we had an HPV-3 his times were actually faster than half of the HPV-4 field. And he isn't an IKF hotshoe ... just a club racer who comes out every now and then.
MS98 won't make the karts slower. Its a great fuel. If anything MS98 could possibly make just slightly more power. MS98 has been the spec fuel for TaG and Shifters for years. MS93 has been the spec fuel for Rotax. These motors run worse on VP110.

Voting
SDKA always encourages members to attend the Board meetings where issues are discussed and voted on. Proposals for rules changes are always discussed at the October meeting and voted on at the November meeting. At the races leading up to these key Board meetings the importance of attending is mentioned at the drivers meetings. Reminders are also posted on the home page and the forum to encourage members to attend the October and November Board meetings.

Thanks,
Jeff Shadoan, V.P.

[dougring]

Guys,

A little background regarding Sr. HPV and SDKA:

* We ran HPV-3 for years (I started in 1999), and changed to -04 in 2001 (as I recall) because a vocal member said the -4 would be faster. So, who doesn't want to go faster?
* Truth is, -3 and -4 are very, very close in lap times. I think it is the classic "more mid range vs. more top end" debate for 2-strokes. In hind sight, we never should have changed over - we really gained nothing. Your lap times will be essentially the same as last year. You will need to talk to your motor builder regarding tuning changes - I think you will target a slightly lower peak RPM (good for motor longevity), and timing may need to be adjusted a bit.
* The noise issue is very real, and we (the club board) are taking an active role in trying to reduce wherever we can. Per my measurements taken during the September race, Shifters and HPV Sr. were the two classes with the loudest karts, so we have taken (what we think are) reasonable steps to quiet them as much as possible.

We have at least one more board meeting (January 14) scheduled before our first race, so I think that would be a good forum to discuss any questions with the full board.

Thanks,
Doug Ring - TAG Sr. #8