05-10-2006, 07:51 PM #1
- Join Date
- May 2006
Aftermarket Heads add to top end?
Seems like quite a few people have added aftermarket heads, or had there oem heads milled. Most seem to say it increases throttle response, but I havn't read much on these doing much for adding mph. Does simply switching to aftermarket heads do anything for top end? 1 or 2 mph?
Also, I can't quite picture what type of performance this would add to the bottom/mid range. Is it a night and day difference like the Jetworks mod that I've read about, which from the many posts that rave about it I can picture quite well :P
Lastly, is changing heads as simple as removing the bolts holding the originals in place, and replacing them with the new ones? If this is the case, it seems pretty straight forward and would seem like only a 15-20 min project? Thanks again board!
05-10-2006, 08:08 PM #2
Heads are a great mod. While just a head will probably not increase top speed, they will allow you to turn a bigger prop which will increase speed. What I found to be the best part of adding heads is the mid-range. A lot of guys use the analogy that the ski feels like it lost about 100 pounds and this is dead on. You can feel the power. I went with the Pro-tec 1 piece rec head and it is a very nice piece. Also, the install is very simple, take the old head off, throw on a new head gasket and torque the new head back on.
Hope this helps
05-10-2006, 08:11 PM #3
Adding aftermarket heads with a lower volume (cc); will in turn increase the the ratio of the volume of air and fuel before and after it is compressed in an engine and will produce more power....to an extent
A higher compression ratio "makes the engine more efficient, because you expand the burned gases more and extract more energy out of them.
Basically, the higher Compression makes the explosion more powerful !
More power equates to more bottom end grunt, midrange and possibly more top end if the components of the motor are paired properly for the modification of the higher compression.
Other things needs to be considered when adding a higher compression such as the octane of gasoline and included with that is the burn rate of the fuel and this can in turn promote detonation if the octane is not properly matched with the right altitude, back pressure, squish, spark generation, timing and compression ratio.
There is a limit on how high you really need to go before problems arise when raising compression ratios and running certains grades of pump gas.
05-10-2006, 08:42 PM #4
I will go along with all that has been said here. A head is one of the best mods you can do by far. The ski feels much lighter and responsive, night and day difference on bottom and mid-range. You may pick up some top end depending on how you're propped as it will enable you to turn more prop.
Users Browsing this Thread
There are currently 1 users browsing this thread. (0 members and 1 guests)
By spellcast1 in forum Yamaha PWC Performance (2-stroke)Replies: 14Last Post: 11-18-2010, 03:42 PM
By 00gprNC in forum Yamaha ClassifiedsReplies: 10Last Post: 10-26-2009, 11:17 AM
By malibu65 in forum Yamaha ClassifiedsReplies: 5Last Post: 09-22-2009, 11:33 PM
By syclonedriver in forum Yamaha PWC Performance (2-stroke)Replies: 14Last Post: 10-15-2008, 10:57 AM
By crashhard in forum Yamaha ClassifiedsReplies: 3Last Post: 09-05-2008, 07:31 PM