Power factory pipe setup/tuning

[Octane_114]

I have recently switched to a power factory exhaust, while i have a decent hand tuning the b-pipe I was wondering if there’s any tips or tricks i need to be aware of. My engine makes good power but I know there’s a lot more I’m not getting out of her. I have the carbs rich and I know I need a larger impeller. Only spinning 7200-7300 rpms. Engine peaks at 7800 haven’t been able to hit the mark.

 

[Half flip95]

7800 is way up there. conventional wisdom would say to use a smaller impeller to get into the higher rpms, but It's hard to see the whole picture when posting online.

what ski is it in? tuning for max rpm may be difficult on a freestyle hull

have you ran this engine before? with the bpipe? what is it doing differently?

 

[Octane_114]

7800 is way up there. conventional wisdom would say to use a smaller impeller to get into the higher rpms, but It's hard to see the whole picture when posting online.

what ski is it in? tuning for max rpm may be difficult on a freestyle hull

have you ran this engine before? with the bpipe? what is it doing differently?

The hull is a bullett gen2 x2, it’s probably an one off set up. Kawasaki 920cc, boyesen intake and reeds, 48 novi’s (I have a set of 49 f/s) just not changing anything at this time. oem sxr ignition - with the 6 degree timing advance, 210psi each cylinder. 145 skat pump 11/18 impeller. Any over 3/4 throttle she just gets loud and it feels like it looses a little forward thrust.

I ran her with several different chambers before I switch to the powerfactory. started with the sxr chamber, then a Japanese motine chamber and last was my c4 which was the best. Hit the hardest and pulled from bottom to top. The b-pipe has its limits too. I also ran a 9/17 at time and any over 3/4 throttle it just got loud too. I turned the highest rpms with that chamber 7460.

I don’t know that I have to run 7800 but that where the engine peaks out. I most ride the ride and lake, chasing my friends with 1100’s. They are 61-62mph I’m maybe 55-57 max. My wife’s sxr is 55mph with a flywheel and wet pipe and my ski is just a bit faster.

 

[Half flip95]

And you’re running like 110 leaded fuel?

my experience has been about +300 rpm going from a wet to to dry pipe. If the wet pipe is pushing 7400 it sounds like you are not over propped and the dry pipe should push it a bit higher.
A few things I’d start looking at :
Pipe temp- straight cold water to the outer jacket can sometimes hurt performance. You definitely need a restriction on the outlet to keep the jacket “primed”

is it a new chamber? Or used / modified / cracked?

Are you using water injection? Is the solenoid working as intended?

Are the o-rings and coupler new? It may be pushing an exhaust leak as rpm build. One that you won’t see at idle.

 

[Storbeck]

If I was trying to go fast with a Kawasaki and a dry pipe, the guy I'd be listening to is @MTRHEAD.

But I'll take a stab and say that I'm pretty sure the stock SXR ignition adds a bunch of advance at high rpms and that on top of your static advance, high compression, and dry pipe at high rpms for long pulls is probably no bueno. Possibly the advance is making it refuse to rev?

Also how do you know that your peak should be at 7800? I would think trying to get a 920cc motor to make power that high would take some serious porting, and would be awfully hard on your bottom end.

 

[Storbeck]

SXR 800 Ignition Timing Curve - PWCToday

Post topics relevant to PWCs in this Kawasaki Jetski Forum.

www.pwctoday.com

Looks like I'm wrong, doesn't add the timing until higher than what you have going on.

 

[long beach local]

Sounds like you need a triple. Probably maxxed out

 

[Octane_114]

pondracer95 - my exhaust is new, o-ringed style. No water injection, only the fcv that comes with it. I do have a lot of water in the chambers so I do know I need to start reducing it. I try a always do a good warm up on the trailer, running 110 and maximum k2 40:1

Shorbeck - it’s more setup like a sprint boat, try not to hold it over 10 seconds. Tpe built my Dasa back in the day. She has all kind of work done. I have thought about lowering the compression to 180psi but that’s after this crank goes and I installed the stroker.

Long Beach - I have two twins an Dasa 850 and my 920 not giving them up. I know that there’s twins out there running 66-69’ish depending on his impeller. He runs a Miller 1021 in an sxr.

 

[Octane_114]

You might try a different Impeller in that 145 mm Pump.

Generally, a 10/18 will yield about 56 mph @ 7500 rpm. An 11/19 will yield about 60 mph @ 7400 rpm. Both in 144 mm Pumps.

Those SXR Triples running 60+ mph are using way taller Impellers in the 16/21-23 range with 140/142 mm Pumps.

Could also try lowering the Compression to say 180 psi, and see if the Engine is suffering from "Pumping Losses" at 210 psi. Hard to Rev against high Compression.

I have wondered about both, I guess the pump more than compression. I checked and it’s 12/18 but i believe it’s still too small I believe I need to be around 16/24. I don’t know what that is going to do to my rpms and if my engine will make power if that impeller holds it in the lower rpms range. do you think I went to large on the pump? Wonder how it would be with a 140.

I have played with 2strokes for a long time and the best way for me to describe it, is it just feels and sounds like the engine won’t get on the pipe.

 

[Half flip95]

I just re read through this.

You can’t compare rpm numbers from the wet pipe to the dry pipe if you changed impellers. You can only change one variable at a time.

also, the power factor is a dry pipe. Putting a bunch of water to the chamber without electronic injection is going to keep it from revving out.

take all of the water out of the chamber and see what it does.

 

[Octane_114]

I just re read through this.

You can’t compare rpm numbers from the wet pipe to the dry pipe if you changed impellers. You can only change one variable at a time.

also, the power factor is a dry pipe. Putting a bunch of water to the chamber without electronic injection is going to keep it from revving out.

take all of the water out of the chamber and see what it does.

I ran the impeller the same with the motine and c4 chambers, started throwing more fuel (larger jets) because she was getting a little lean on top. I do agree about changing one part at a time. (c4 and motine I ended with 11/17) ski still fell off after 3/4 throttle.

That is when I decided to run the ski with the power factory, two or three rides with power factory and 11/17 then repitched to 12/18. —- all work was done by Dave last repitch was done by Glynn.

 

[Octane_114]

that is where I will start this weekend, reducing the water in the chamber. I really appreciate everyone’s input.

 

[Storbeck]

What exactly do you mean by "water in the chamber"? You said no water injection which sounded like you are running the chamber dry (which would make sense if you're looking for 7800rpm) and you said "only the fcv valve that comes with it" which would be controlling water in the stinger/waterbox, not what most people would refer to as water in the chamber.

Also once you are anywhere near full rpm the flow control valve is open and makes no difference. There should be a jet in the water inlet to the stinger, which will be what is controlling the amount of water in the stinger/waterbox when you are at high rpm/speed. That's a completely different thing from water in the pipe though.

 

[Storbeck]

Also still wondering where the 7800 rpm thing came from. If somebody is familiar enough with your motor/pipe combo to tell you 7800rpm usually they would be the one helping with this stuff.

 

[Octane_114]

Also still wondering where the 7800 rpm thing came from. If somebody is familiar enough with your motor/pipe combo to tell you 7800rpm usually they would be the one helping with this stuff.

Eric b. built my engine many years ago, he helped me for while but can’t expect him to be my crew chief. I really don’t know anyone running the my engine/pipe combo in a river racer/sprint boat setup. It’s usually a freestyle flipper ski.

 

[Octane_114]

I feed water to the exhaust manifold from the pump. manifold to chamber, chamber to overboard.

 

[Octane_114]

What exactly do you mean by "water in the chamber"? You said no water injection which sounded like you are running the chamber dry (which would make sense if you're looking for 7800rpm) and you said "only the fcv valve that comes with it" which would be controlling water in the stinger/waterbox, not what most people would refer to as water in the chamber.

Also once you are anywhere near full rpm the flow control valve is open and makes no difference. There should be a jet in the water inlet to the stinger, which will be what is controlling the amount of water in the stinger/waterbox when you are at high rpm/speed. That's a completely different thing from water in the pipe though.

I’m new to this exhaust, trying to figure it out, maybe my wording is off? I do understand how the fcv works, ran one for a while. I bought both of my power factory systems new and i don’t have a jet in the chamber like the sxr chamber does.

 

[fastgtfairlane]

The flow control just keeps the waterbox from loading up with water and should start opening up by 25-3k rpm. More water in the stinger in upper rpms will actually give more top end power.

 

[MTRHEAD]

The hull is a bullett gen2 x2, it’s probably an one off set up. Kawasaki 920cc, boyesen intake and reeds, 48 novi’s (I have a set of 49 f/s) just not changing anything at this time. oem sxr ignition - with the 6 degree timing advance, 210psi each cylinder. 145 skat pump 11/18 impeller. Any over 3/4 throttle she just gets loud and it feels like it looses a little forward thrust.

I ran her with several different chambers before I switch to the powerfactory. started with the sxr chamber, then a Japanese motine chamber and last was my c4 which was the best. Hit the hardest and pulled from bottom to top. The b-pipe has its limits too. I also ran a 9/17 at time and any over 3/4 throttle it just got loud too. I turned the highest rpms with that chamber 7460.

I don’t know that I have to run 7800 but that where the engine peaks out. I most ride the ride and lake, chasing my friends with 1100’s. They are 61-62mph I’m maybe 55-57 max. My wife’s sxr is 55mph with a flywheel and wet pipe and my ski is just a bit faster.

Holy smokes
7700-7800 is easy with correct setup
I’m going to assume you have serious porting like 196-200 exhaust and 128-130 transfers.

#1 I have no idea the drag of that hull
#2 look at the attached oem timing curve. Your not going to spin 7800 with the oem curve easily and you wont with +6 degrees without seriously bad consequences. 7800 requires about 10-12 degrees of advance at that RPM. That’s what most of us ran when spinning that kind of rpm
#3. What hub is in your 145?
I spun a 14/24 (bent from a 14/23) 7600-7800 in all my Kawasaki’s in a 142mm/75 hub pump with a 83 nozzle
#4. What size stinger is in the pipe?

 

[MTRHEAD]

Timing curve without any advance