Reply With QuoteA little good basic info for ya to start with as I am not one of the guys running high-speeds (over 80).
Impeller Choice
Make sure to fit your impeller and engine so you can get to your engine's peak power. This seems kind of confusing I will try to clarify. I have seen instances of big HP engines being too weak on Torque in the lower-mid range (3K to 5K RPM) to be able to reach their HP which was up above 6K. Usually not a problem with blower motors tho.
Here is one link to get some info, and has a chart at the bottom.
http://www.berkeleyjet.com/products/impeller-info.htm
In general, larger impellers push more water at lower RPM's and accelerate better/quicker, smaller impellers spun faster run faster on top end. This is not a guarantee, nor a hard & fast rule, but is generally accurate. A lot relates to your engine also.
Top Loader
The faster you go, the harder it is to get water to turn the corner and go UP into your pump. The bottom of the impeller sees increased water pressure while the top looses pressure. At some point, this results in cavitation. A top-loader (loader) helps this as it guides more water toward the top of the pump to feed the impeller evenly. There are a lot of different designs, some work better on some aplications, others on others. Only 1 way to find out which is best, spend $$ and test-run it (or borrow one).
Ride Plate
For best top end speed, you need to get as much of the boat airborne as possible. Air drag is a fraction of what water drag is. The ride plate serves 2 purposes IMO. 1, to help "set" the attitude of the hull to the optimum angle when the boat is flat out and the jet nozzle (diverted up making a roostertail) is trying to lift the hull as high as it can. 2, to prevent the hull from lifting too much inducing a porpose (on most v-hulls and at lower speeds) and to try to prevent the boat from catching too much air and flipping over (the FAST boats, tunnels & hydros generally).
Nozzle Diverter
The most useful and desireable thing on a lake-jet-boat IMO. It allows the nozzle to be aimed up & down to allow you to deal with various water conditions and activities. Wityh a nozzle trimmed downward, it helps deal with rougher choppy water, and IMO helps with holeshot/pulling acceleration. Trimmed fully up helps lift the bow, fly the hull dry, to get maximum speed. Anywhere in between depending on water conditions. I set about level towing tubes/skiiers. I set aprox 1/2 full up cruising to get best speed at moderate RPM. I cannot carry full up at cruise unless water is very smooth, a mild porpose sets in and is annoying.
Shoe
The back edge of the pump inlet, generally adjustable by shimming or grinding/filing. This is the part that actually scoops, the loader does not generally stick out below the boat. You can have it too low below the boat and feed too much water to the pump, drag then slows ya down. Too high up and the pump starves at higher speeds.
Straight Snoots & Droop Snoots
Extensions between the bowl and the nozzle. Sometimes helps with the setup on a particular boat, sometimes not. The droop seems to help lift the stern higher at speed. The straight snoot adds length to the pump and helps the nozzle lift the bow (leverage) of a heavy-nosed boat.
If you notice a theme of "each boat is different, and one setup may or may not work as well on another boat", then you are right. The hardest part about making a jet perform at it's best is the fine-tuning of all the parts. There is a lot of knowledge here that is willing to help ya go in the right direction.
That is about all the comonplace parts that there are. I think I got all the basics correct, more experienced speed guys can come on here & refine it. My Taylor was bought by my father 28 years ago, been driving it about 25 years, she has been mine for 3. I've been watching and learning a lot over the last 3 years.
