Gut guys ?? Okay fat boy , I don't care what ya call us weight conscious dudes , but don't mess with our titanium addiction !! 
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PPR Titanium Valves . . . Increase Flow!!
- Thread starter Kiwi Rider
- Start date
Hayabusa Wannabe
Registered
Correct me if I am wrong but this flow test seems to fix the valve in place. Are there tests that actuate the valve? Otherwise how would one in the lab reproduce a benefit in duration talked about above?
Mmmmmm . . . .
the duration is the amount of time the valve is open, so this test is measuring flow over time = duration.
Hayabusa Wannabe
Registered
I think you may have missed the point. The test has a fixed duration. The issue is testing that a titanium valve by its mere mass savings creates a different duration or allows for it.
My thinking (correct me) is that a a fixed valve on a bench does not reflect real-life duration. In an engine valves do not open instantaneously but open on a curve according to a cam profile, none of which is reflected here. Thus I think the flow advantage in this test video only reflects differences caused by the shape of the two valves being tested. Also also a cam would have to be specifically cut to take advantage of a valve with less mass, with an increase in slant/profile. Lastly, a test of a titanium valve's mass benefit would have to be done from measuring engine output.
True? False? Outright fraudulent?
Kiwi; The aftermarket TI valves are thinner (thanks to the stronger material) and therefore effective opening is more like 30thou lift instead of the normally measured 50 so the effective duration of the cam is greater.
Thats my story and I'm sticking to it!
I'm trying to wrap my tired brain around that.
If the valve is thinner(I agree with the, it can be thinner because stronger part), the thinner would be between the valve face, and the surface that contacts the seat, yes? And, if so, the distance from the valve seat surface to the tip of the stem would remain the same
I think it's the shape, thinner from stronger material as was said. So the top side of the valve face is not as tall, allowing more flow where there had previously been valve material.
At least that's what I gather from it all now.
Mathewrussell52
Registered
They don’t give a stem diameter on the website so I assume they are stock. And these valves are coated with titanium.
It could be the shape of the valve head itself or where the seat is located on the valve.
As an aside I have a buddy the runs a green bike, boooo, that has stock Gen I Hayabusa valves in it because they flow better. I guess the green valves are shaped more like a nail then the Busa. Don't know never held them side by side.
As an aside I have a buddy the runs a green bike, boooo, that has stock Gen I Hayabusa valves in it because they flow better. I guess the green valves are shaped more like a nail then the Busa. Don't know never held them side by side.
Bailey9r
Registered
Exactly on your last line, an inch and a half door opened two inches will have a 1/2 inch gap (lift) and a thinner one inch door with the same two inch opening would have a full one inch opening effectively giving more duration. (the gap started as soon as the inch passed)
Unklpunk
Registered
the test was done on different cylinders, stock was done on cyl 2 ppr on cyl 3. flow numbers at a lower lift would be interesting to see. the stem could be reduced diameter from the guide to the valve head. a local engine builder who has flowed lots of heads said a ballpark rule of thumb is 1/2 the cfm in hp. so that would be 4 hp a cyl x4 =16 hp gain. modern head design may be greater. thats significant. id like to see low lift numbers, and a more consistent test.
ali123
Banned
no way.. and I gotta figure if they had HP numbers that good... we would see back to back dyno runs and not a useless flow bench result.
This has really taken off, I thought when I started this thread it would fizzle out with little interest .. . . . . NOT SO!
Very cool, amazing how much engineering knowledge you lot have to offer . . . very very cool.
Very cool, amazing how much engineering knowledge you lot have to offer . . . very very cool.
Unklpunk
Registered
I guess I was trying to be somewhat sarcastic, if they had that kinda improvement, we’d all be buying. My brain doesn’t think so good lately.
ali123
Banned
nothing wrong with ure brain... I just don't like it when a company tries to do things like that.,.. be kinda deceitful
Unklpunk
Registered
I agree, back turned to the camera, can’t see the screen, just played with a cfm/hp calculator, gen2 11000rpm uses 258cfm at 100%ve. So maybe with modern 4 valve head and good port 108%ve or 278cfm. That’s all 4 cylinders. One cylinder 70cfm. MPS racing big lift cam is .460. Then .445,.425 etc. Flow at.5 inch is useless. I have a rough day ahead and my brain is already sore, and not from this, this is a temporary diversion.
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