pv or not

[catch me if u can]

just tryin to catch some opinions i ride alot of woods and trials and was going to get a 310 or 305 but do you think i should get a powervale what is the advantages and disavadages thanks

[ky 2stroker]

how much money do you have to spend?, that is the main 1st question

[bmxnick7]

i have a 310 none pv and it is an animal, i love it worth every penny, but if you have the extra cash a pv wont hurt

[catch me if u can]

money is not really an object

[bushwesl]

Originally Posted by catch me if u can

money is not really an object

Must be nice...

Anyway, I would definitely go with a PV, especially considering your financial situation, ha. I don't know how much you actually know about PV's and how they work, but basically what a PV does is creates a broader power band/curve, whereas a non-PV cylinder can have more of a light switch power band/curve. Although, everything depends on your porting, etc, etc.

The PV itself is an exhaust valve that is driven off from exhaust gas pressure. The valve closes at lower RPMs and then opens up at higher RPMs.

The advantages of a PV cylinder are that it allows for a broader power band/curve. This allows the engine to act more like a 4-stroke and have more tractible power, e.g. less wheel spin. It also allows you to port your cylinder more aggressively, e.g. mid to upper mid range, and not compromise low end power/grunt due to the PV.

The primary disadvantages are the price, for one, and also the fact that some PV's don't work as well as others.

[catch me if u can]

where would you reccomend me to get the pv cylinder from i was thinking about esr have you heard good things about there pv

[bushwesl]

Unfortunately, I've never owned a PV cylinder, or have any real seat time/experience with one, but from what I've heard from several people, including some world class builders, is that the Rotax style PV is the best, which is offered by Duncan, FTZ, and LRD, then comes CT Racing's PV, and then lastly, ESR's PV. The reason the ESR PV is less desirable is because from what I've heard their PV opens too quickly, and is either open or closed, nothing in between. The PV should open proportionally to the RPM's.

[fourtrax250r]

the powervalve partially closes the exhaust port at lower rpms becasue a smaller exhaust port will make more power lower in the rpm range and then it opens as the rpms increase to allow exhaust port to become "larger" which makes more power higher in the rpm range. the result is more low end grunt without topend sacrifice. the power becomes more tractable and you can get out of the hole quicker and shift less.

the powervalve is definatley worth it in the woods and is a good choice for anything besides drag racing.

[catch me if u can]

why is it not good for drag racing

[fourtrax250r]

its not necesarily bad but you launch with the PV fully open anyways and keep it open all the down the track so it does nothing. for drag racing it would just be expensive dead weight. its also another thing that can go wrong if it doesnt open all the way or sticks your run will be ruined.