Power Factor Exhaust vs. RRP Carbon Ninja Exhaust

[Nicotheskiguy]

I’m considering doing some upgrades to my ski over the off season and wanted some input on the different exhaust systems that are out there. Currently am running a B pipe but I fell like my bottom end is lacking. I also plan on upgrading the 144 solas to a 148 setback torrent as well as zeeltronics but was going to upgrade exhaust first to see what happens.

What is an all around better pipe for a 865cc stroker motor? Going in a Gen 2 BOB

Is there a noticeable difference between the power factor and rrp? I figure if I ever want to upgrade motors the rrp would be better to have but want some input from the guys who have tested! (Yes the B pipe will be for sale in a month or so, my season ain’t over yet)

 

[800750]

I have ran both personally on the same 701 and you can't go wrong with either vs a b pipe imo. Currently I have the pfp installed and as my riding has progressed I prefer the pfp. Also rrp pipes seem impossible to find, tricky usually has a pfp In stock it seems like. A little timing and compression and the power factor gets my vote. And either will work great on a 701-1200. It's all about the pump setup but the pfp gets my vote. Seems to pull longer and smoother. ( I classify myself as a backyard hack so don't take what I say to heart.)

 

[kevbo]

Lacking bottom end? The "b" pipe tends to have longer tuning than the wrap around styles so your problem may get worse. I would look to the pump first, a tiny little impeller bend can make a huge difference.

 

[Nicotheskiguy]

Lacking bottom end? The "b" pipe tends to have longer tuning than the wrap around styles so your problem may get worse. I would look to the pump first, a tiny little impeller bend can make a huge difference.

I’ll have to give that a shot, @Jr. suggested doing the same, didn’t know how I felt about about bending a $300 prop but since you’re not the first to suggest I’ll give it a try

 

[Harbor]

My 8 mil Lamey on race gas, 4 hole 44’s and Msd enhancer with 144 sol mag and 11/17 hooker made plenty of bottom end with a mod b- pipe…. So kinda wondering if yours actually lakes bottom or if you’ve got something else going on preventing it?

On the pipes, I waited a long time switching to a lay down pipe.. but once I did switch I regretted waiting so long.. the RRP made a huge difference…

I run the pf on a larger engine and like it too…

You might check with Derrick sr at the ski clinic on fitment of both pipes/water boxes, first

I have a Max 148 and can maybe give you the prop pitch ?

If your going to re-pump in the future, can the hull handle a 155 ?

 

[Nicotheskiguy]

My 8 mil Lamey on race gas, 4 hole 44’s and Msd enhancer with 144 sol mag and 11/17 hooker made plenty of bottom end with a mod b- pipe…. So kinda wondering if yours actually lakes bottom or if you’ve got something else going on preventing it?

On the pipes, I waited a long time switching to a lay down pipe.. but once I did switch I regretted waiting so long.. the RRP made a huge difference…

I run the pf on a larger engine and like it too…

You might check with Derrick sr at the ski clinic on fitment of both pipes/water boxes, first

I have a Max 148 and can maybe give you the prop pitch ?

If your going to re-pump in the future, can the hull handle a 155 ?

The only difference to what you’ve listed vs mine is I have dual 46 mikunis (heard mixed emotions on them at the latest freeride) and a 9/15 hooker and I’m only running an enhancer right now
I have not messed with timing yet and the squish is high (barely out of ideal range) I’ll probably pull a gasket under the cylinder this winter. Sitting at 185 comp with a barely high squish

148 is the largest the Gen 2 can fit.
I can’t say for certain whether I have a mod or limited pipe.

It looks like I would have more than enough room in the bay for it but I’ll try and figure out how to get in contact with Derrick Sr.

 

[ngerk]

Wouldn’t you need something steeper? I ran a stock stroke 865 (I know, different engines) in a carbon gen 2 and had an 11/17 and it had plenty of bottom end. A lay down pipe won’t help the bottom end at all plus you would most likely need to run wet if you went PFP. I swapped hulls and went to a 155 and PFP on the 865. Super laggy on the bottom end. I probably could have pitched down but running the pipe wet fixed it. I’m on a big motor now and was able to go back to a dry pipe which I believe is an advantage to the PFP, best of both worlds.

Anyways, my brother in law has the gen 2 BOB hull as well as my 865 now and to answer a couple questions, a lay down pipe and 155 work fine. Obviously need to swap pump shoes. Also enhancer to Zeeltronic is a huge upgrade.

 

[Nicotheskiguy]

Wouldn’t you need something steeper? I ran a stock stroke 865 (I know, different engines) in a carbon gen 2 and had an 11/17 and it had plenty of bottom end. A lay down pipe won’t help the bottom end at all plus you would most likely need to run wet if you went PFP. I swapped hulls and went to a 155 and PFP on the 865. Super laggy on the bottom end. I probably could have pitched down but running the pipe wet fixed it. I’m on a big motor now and was able to go back to a dry pipe which I believe is an advantage to the PFP, best of both worlds.

Anyways, my brother in law has the gen 2 BOB hull as well as my 865 now and to answer a couple questions, a lay down pipe and 155 work fine. Obviously need to swap pump shoes. Also enhancer to Zeeltronic is a huge upgrade.

Good information! A steeper pitch seems like it could alleviate my problem, switched to a jet dynamic grate and hookup is so much better but it almost feels like my pump is immediately blowing all water through when jumping, flipping etc. It feels like thrust is lacking a lot!

Before the pipe zeeltronics is definitely on the list so is repitching the prop I will also attempt to dry out my flow control valve I totally forgot to “tune” it this year but shouldn’t matter since I’m running a resonator. (I need to find myself a water box that’ll fit)

 

[fastgtfairlane]

So you're running a 865 with a 144 mag and a hooker 9/15? That's definitely not enough impeller for a 865.

 

[Nicotheskiguy]

So you're running a 865 with a 144 mag and a hooker 9/15? That's definitely not enough impeller for a 865.

What would you suggest I try? An 11/18?

 

[fastgtfairlane]

What would you suggest I try? An 11/18?

11/18 at minimum. a 9/15 is more for a stockish engine ski. a riding buddy has a 735 with a 144 mag, pipe, zeel, porting etc and has a 9/15 with a mag pump, bored nozzle and he could benefit from more impeller. i think a 10/16 would be perfect for him. his sounds similar to yours that the engine revs quickly but the ski doesnt quite pull with the way the engine revs because the impeller isnt grabbing enough water to load the engine as much as it could. no cavitation or anything just not enough pull. ive seen a several instances where getting the impeller pitch dialed results in increases both in bottom and top end.

 

[Yami-Rider]

Lacking bottom, yet your running way too small of prop, the engine should just be spinning out with that tiny of a prop, unless your engine is very poorly tuned.

RRP will make more bottom end then PFP. On that small of a engine w/ PFP, itll need 30 degrees timing down low, or it will be a dog on bottom.

 

[kevbo]

So you're running a 865 with a 144 mag and a hooker 9/15? That's definitely not enough impeller for a 865.

That depends on which 9-15 you have. A Solas would be way too much, a Hooker may be on the light side. Besides all that, the port height and pipe combo are huge factors. It is much more difficult to get a high rpm setup to spool up fast. Often freestyle impellers end up on the lite side of perfect. Its a fine adjustment that is hard to predict so you almost always have to spend some time and adjust the pump load. Its a little harder than getting carbs perfect but every bit a critical.

 

[Nicotheskiguy]

Lacking bottom, yet your running way too small of prop, the engine should just be spinning out with that tiny of a prop, unless your engine is very poorly tuned.

RRP will make more bottom end then PFP. On that small of a engine w/ PFP, itll need 30 degrees timing down low, or it will be a dog on bottom.

You nailed it on the head that’s exactly what’s going on! Engine is tuned great just having “thrust” issues I called it bottom end. The pump does feel like it’s spinning out or not building up enough pressure which I’m guessing is what happens when you have too small of a prop?

 

[Yami-Rider]

Ya, sounds like it, You should be at a 11/17 hooker with that setup. You can send your 9/15 hooker off to impros and have repitched.

Or if your going 148 now, just buy a 8/15 skat-trak cutback 5mm 148 magnum impeller.