n2otoofast4u Posted October 29, 2013 Report Share Posted October 29, 2013 Simulation? I don't follow. Can you elaborate more on this Gary? Quote Link to comment Share on other sites More sharing options...
srp Posted October 29, 2013 Report Share Posted October 29, 2013 Simulation? I don't follow. Can you elaborate more on this Gary? My engine design and simulation software uses Young's Modulus to study reed behavior and lift, the software will predict total reed lift, reed cage time/area, actual time/area across the petals, reed petal frequency, intake velocity, BMEP, direction of flow at important timing events and amplitude inside the intake pipe as the reed petals close. The software will predict an unstable reed petal if the lift ratio is much above 30% (reed max lift divided by reed un-clamped length), If the reed is unstable and floats it will close late and the inertia of the intake pipe will have to do most of the work keeping the charge in the crankcase. If everything goes right the reed closes on time and the charge inside the intake pipe sneaks into the crankcase just as the reed petals close, this will raise pressure inside the crankcase much like a very small supercharger would do. Cubs above 392 cc will have excessive primary compression and reed tip ratios at and above 30% unless the builder has adjusted it. The reed stops on the VF4 will help stable the reeds on these engines or so the math says. To learn more read Gordon Blair's Design and Simulation of Two-stroke Engines (Chapter 6), for the math Gordon Blair's The Basic Design of Two-stroke Engines and Google Young's Modulus. Quote Link to comment Share on other sites More sharing options...
Glenyboy Posted October 29, 2013 Report Share Posted October 29, 2013 Simulation? I don't follow. Can you elaborate more on this Gary? He used the lawn mower man program Quote Link to comment Share on other sites More sharing options...
sprinklerman Posted October 29, 2013 Report Share Posted October 29, 2013 He used the lawn mower man program I see what you did there. The original movie was before a lot of these guys time though. haha Quote Link to comment Share on other sites More sharing options...
KaN Powersports Posted October 30, 2013 Report Share Posted October 30, 2013 If you had a 10 mill making 77 HP you would know not to run those stupid undersized Paul Turners on the damn thing. 99% of people who say a dyno can be manipulated are just repeating stuff they have heard. For the purposes of testing all they are doing is swapping reeds. The results of THAT experiment are almost identical to the results YOU will have. Because most riders don't have their motor dialed in perfect in the first place.....so a before and after test with zero tuning is exactly the way you would run your machine if you bought new reeds. (If you did a little research, you might go up one pilot jet size and gain better rideability and midrange power.) V-4's FTW! Using a dyno to prove stuff instead of taking the word of 100 fools and their Butt Dyno opinions FTW X2! As long as the bike wasn't moved, among a myriad of other variables. I can make 8 more horsepower on my dyno by loosening the tie downs a bit. V4's are for real, but I think too much stock is put into Dyno readings. I have used a set of reeds from a sled in a stocker that are 'caged' like the v4's and have Boyeson petals modified and installed in them-worked out real well for that 'stocker'. Made 5hp difference, but again too much stock put into readings-they were better though. I didn't get as detailed as the posts above, but 'flutter' is exactly what I was taking away for the mods with this stock cylinder I set-up Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted October 30, 2013 Report Share Posted October 30, 2013 People keep acknowledging the difference but then they make every excuse on why it is probably a bogus run. Ok, new rule. You can't say they are junk unless you have the dyno/track run to prove it..... Quote Link to comment Share on other sites More sharing options...
sprinklerman Posted October 30, 2013 Report Share Posted October 30, 2013 I will say i like the updated reed stops. They "look" like they should improve reed life. Whats funny is how they mimic the factory stoppers that we are so quick to throw away right off the bat. I know there's a lot more to reed performance than just the stoppers , but i got a kick out of the similarities. Quote Link to comment Share on other sites More sharing options...
Hazzard Racing Customs Posted October 30, 2013 Report Share Posted October 30, 2013 I will say i like the updated reed stops. They "look" like they should improve reed life. Whats funny is how they mimic the factory stoppers that we are so quick to throw away right off the bat. I know there's a lot more to reed performance than just the stoppers , but i got a kick out of the similarities. totally agree here it is funny i have tons of these stoppers and always think what is the point but then the 4's come out and kick me in the teeth!!!!!!!!! Quote Link to comment Share on other sites More sharing options...
Coupelx Posted October 30, 2013 Report Share Posted October 30, 2013 Ive made a few posts about the importance of keeping reed stops. It was one of the biggest reasons i stayed away from vf reeds. Quote Link to comment Share on other sites More sharing options...
possum Posted October 31, 2013 Report Share Posted October 31, 2013 I was told the stops are hurting the 4s. Quote Link to comment Share on other sites More sharing options...
WINDYCITYJOHN400 Posted October 31, 2013 Report Share Posted October 31, 2013 I was told the stops are hurting the 4s. FFS! Next somebody is going say the stuffers hurt performance......99.8% just talking out their ass. 75% haven't even held a set in their hand let alone TEST a set. But everybody has to say something to look like they know something......... Quote Link to comment Share on other sites More sharing options...
Glenyboy Posted October 31, 2013 Report Share Posted October 31, 2013 Stuffers hurt performance Quote Link to comment Share on other sites More sharing options...
Hazzard Racing Customs Posted October 31, 2013 Report Share Posted October 31, 2013 this horse is dead to the world Quote Link to comment Share on other sites More sharing options...
KaN Powersports Posted November 7, 2013 Report Share Posted November 7, 2013 It's been a few days and I was walking by the dead horse, so I thought I'd give it kick-hahaha Quote Link to comment Share on other sites More sharing options...
Coupelx Posted November 7, 2013 Report Share Posted November 7, 2013 Stop its starting to smell. Quote Link to comment Share on other sites More sharing options...
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