Other Bpipe vs. PFP
- Thread starter Pablo
- Start date
raytherace
Canadian Brapp Dealer
- Location
- St-Ray Beach, QC
There is no pics in that thread only one vid. the link in the last post is wet jet pipe.
waxhead
wannabe backflipper
- Location
- gold coast
dry pipes are awesome on a engine for power output. The pfp is really just a reshaped type9 isnt it.
I find drypipes make more power everywhere. They just dont have the same throttle response that a b-pipe has. In the surf I want throttle response.
I find drypipes make more power everywhere. They just dont have the same throttle response that a b-pipe has. In the surf I want throttle response.
WFO Speedracer
A lifetime ban is like a lifetime warranty !
- Location
- Alabama
Can comment on either pipe, I can however comment on cutting the PV springs, cutting a coil off the spring increases the spring rate making the remaining spring stiffer, the PV's may initially open quicker due to the shorter spring but through the rest of the travel they are now fighting against a stiffer spring, it is not the correct way to achieve the desired results.
- Location
- Rincon Beach
Um.. May want to revisit this, cutting coils off a spring does not change the effective spring weight /stiffness,
Db
WFO Speedracer
A lifetime ban is like a lifetime warranty !
- Location
- Alabama
You might want to do some research on that, I have already
Imagine a 10 coil spring sitting upright on a table. You place 200 lbs on the spring. The weight moves the top of the spring down 1 inch. So your spring rate is 200 lbs per inch. Each one of the ten coils has shrunk 1/10 of an inch.
Now cut the spring in half. You have 5 coils now. When you place the 200 lbs on it, each coil still shrinks 1/10 of an inch. (same diameter coil, same amount of deflection.) Because there's only 5 coils, the spring will only move down 5/10 of an inch.
This gives you a new spring rate of 400 lbs per inch. Twice as short = twice as stiff.
Please share your obvious expertise with the rest of us.
Imagine a 10 coil spring sitting upright on a table. You place 200 lbs on the spring. The weight moves the top of the spring down 1 inch. So your spring rate is 200 lbs per inch. Each one of the ten coils has shrunk 1/10 of an inch.
Now cut the spring in half. You have 5 coils now. When you place the 200 lbs on it, each coil still shrinks 1/10 of an inch. (same diameter coil, same amount of deflection.) Because there's only 5 coils, the spring will only move down 5/10 of an inch.
This gives you a new spring rate of 400 lbs per inch. Twice as short = twice as stiff.
Please share your obvious expertise with the rest of us.
steve-uk
Manners cost nothing
- Location
- Barrie - ontario
heres a question... will a PFP fit in a rok.....
By clipping the spring "shorter" I was thinking that you would need to then make the newly clipped spring fill the same cylindrical void that the old spring (that had more coils) filled. Now you have a new spring (with fewer coils) and less energy would be required to compress the new spring. Is that incorrect? I think it's a benign point since Brian and Josh said they gave it a shot and found nominal changes. It'd be nice if you could have a complete set of springs, like carb springs 60, 80, 95g..., to attempt to tune PV's. I have no idea if it's a worthwhile venture, but I do know once my PV's pop my engine pulls even harder. The consequence is I'm prolly hitting 6-7K rpms when it happens. I don't know enough about variable exhaust timing to know if it's better or worse to have them open from the jump. If performance is better with them open full time then what's the benefit of having them spring loaded? Just make the exhaust port sizes match whatever the size/volume of a fully opened PV port and skip the fancy crap (sounds like a Gomez engine...and I've never felt one of them lack power).
SUPERTUNE
Race Gas Rules
- Location
- Clearwater Fl.
Your missing one key factor here....
Installed spring height.
The spring tension @ your installed height will be less from the spring being cut shorter.
Results are less open max pressure.
This would work just like valve spring in a racing 4 stroke, yes, the spring rate would be close to the same, but only at a shorter installed height.
- Location
- Rincon Beach
Ok, you have researched it, Im not trying to start a debate , so here is your error , your statement here is not true "Now cut the spring in half. You have 5 coils now. When you place the 200 lbs on it, each coil still shrinks 1/10 of an inch."
like I said I dont care how many coils you add or subtract, the deflection per effective coil per pound remains the same (excluding effects of coil bind and end effects)
dB
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WFO Speedracer
A lifetime ban is like a lifetime warranty !
- Location
- Alabama
The coil spring debate is old news, I learned this many years ago cutting coil springs to cars to lower them, it will defiantly lower the car, it will also defiantly make the spring stiffer and the ride harsher, the more coils you cut the harsher the ride will be. Argue all you want, physics can only be manipulated to the point of failure. I took into account the installed height, like I said it would open faster to a certain point because of the shorter spring, as stated earlier what you really need is a softer spring with the same length to achieve the desired results.
GIL
Power In The Hands Of Few
- Location
- Cullman AL
My engine builder says that p/v's are for those that do not know how to properly set up a given engine package. Don't know if he is right or wrong, but I do know that his engines are pretty awesome IMO.
Back on topic-
I have experienced a motor going back to back from B-mod to PFP and my thoughts were the PFP was more power, just much higher in the power curve and as Josh stated, you end up riding at a faster speed to keep the pipe higher in the RPM's to be able to experience the additional power. You have to ride a PFP ski like you would rode a 125cc MX bike-HARD. (If you want the full effect). Ths ski/motor I rode was Crammit's XFT w/a Jetworks 828 6 mil with ALL the good stuff. MSD T/L, MAG, MS109, BlackJacks, on and on and on.
With all that said-I know the PFP guys have played the prop game to hell and back but I wondered when I was riding Crammit's ski w/PFP if a much lower prop pitch would have moved the curve down lower to accomodate the PFP. I do NOT know the answer to this but I am sure Josh can give solid advice here.
Hope this helps.
Back on topic-
I have experienced a motor going back to back from B-mod to PFP and my thoughts were the PFP was more power, just much higher in the power curve and as Josh stated, you end up riding at a faster speed to keep the pipe higher in the RPM's to be able to experience the additional power. You have to ride a PFP ski like you would rode a 125cc MX bike-HARD. (If you want the full effect). Ths ski/motor I rode was Crammit's XFT w/a Jetworks 828 6 mil with ALL the good stuff. MSD T/L, MAG, MS109, BlackJacks, on and on and on.
With all that said-I know the PFP guys have played the prop game to hell and back but I wondered when I was riding Crammit's ski w/PFP if a much lower prop pitch would have moved the curve down lower to accomodate the PFP. I do NOT know the answer to this but I am sure Josh can give solid advice here.
Hope this helps.
Fro Diesel
creative control
- Location
- Kzoo
What about Roo's freak right now.701 wetjet w a pfp. Riiips
Sent from Fro Diesel using Tapatalk.
jetski9010
Team RTYD
- Location
- Lancaster PA
I think it's all about getting the engine to the RPM's that you need for this pipe to come alive so yes I dont see why a 701 couldnt make this work. You guys are talking about the power valves not opening soon enough or the engine doesnt pull out quick enough, I wouldnt mess with the power valve springs just yet why dont you go back to the whole tuned package you have and check everything out. What compression are you running? Can you rise it at all?, Timing/Ignition system? Prop/pump setup do you have to big of a prop on there? If you going from a B pipe to a PF you more then likely going to want to reprop it if not at least do some pump adjustment noze bore/ cone change.
All I am saying a lot of you guys are asking I want a straight anwser if I just take my B pipe off and bolt a power factor right on will I have more power. You just cant judge it like that. I agree with Wax also about the type 9 I have been on some properly tuned skis with type 9 pipes and they pull like crazy too. So for you guys that dont want to run the 2 gal tanks with the PF pipe you should look into a type 9. Just a thought.
- Location
- Lake Orion, Michigan
this is a very rushed together setup, hope some of you get some laughs out of it
arty: i literally pulled out my 1000cc longblock motor, and dropped this 701cc motor in place of it along with stock electronics. (whole reason i did this was because i sent my xs1000 down for a rebuild)the setup pictured below is as follows:
-61x 701 WetJet motor (w/single 46mm carb), 145mm setback mag (13/19 prop), powerfactor pipe, stock ignition
the pump is setup and pitched for my 1000cc motor (145mm setback, 13/19 prop). as is, it is a little ripper but could use some more low end which i am confident once re-pitched, would make a world of difference. i do have a stock 144mm pump with i believe a a lower pitched prop i should try, but honestly just have been bit lazy about swappin' it.
two other things i'd like to try is adding a waterbox for back pressure, and switching the electronics over to total loss and play with the timing.
- Location
- Lake Orion, Michigan
i will say my buddies 61x 701cc, msd enhancer / advanced timing, b-pipe, stock 144mm pump with 9/15 hooker prop did feel a bit snappier then the setup listed above. (his prop is WAY better matched for the application)
- Location
- South Florida
That is a dope flame arrestor. Function over form.
D-Roc
I forgot!
- Location
- Dirty River Rider
i have seen canadian flame arrestors like that on a team ugly ski.
NVJAY775
My home away from home.
- Location
- Gardnerville, Nevada, United States
Great thread. I'm not trying to get into the spring debate whatsoever. But bottom line is, get a softer spring.
As others have said, cutting the spring will increase spring rate. And as Chuck said, the height will be different. So if you shorten the gap (raise height) the rate increases, so it will open even later. If you don't and leave slop in it, it may open quick, but may not open completely, because the rate has been increased. Or space it with something softer than the spring, you may be onto something, like Brian is working on. (Dual rate spring basically)
Spring cutting and rates have been proven in about all forms of motorsports. There are also multiple rate springs available for automotive apps. Even r/c cars lol.
Maybe find out who manufactures the springs and see if they can make softer springs. Or another spring manufacturer maybe. I wish it was as easy as cutting the springs, and changing heights.
As others have said, cutting the spring will increase spring rate. And as Chuck said, the height will be different. So if you shorten the gap (raise height) the rate increases, so it will open even later. If you don't and leave slop in it, it may open quick, but may not open completely, because the rate has been increased. Or space it with something softer than the spring, you may be onto something, like Brian is working on. (Dual rate spring basically)
Spring cutting and rates have been proven in about all forms of motorsports. There are also multiple rate springs available for automotive apps. Even r/c cars lol.
Maybe find out who manufactures the springs and see if they can make softer springs. Or another spring manufacturer maybe. I wish it was as easy as cutting the springs, and changing heights.