| Author | Message | ||
     Superchicken |
Little help here please, I would like to smooth out the bottom end power of my BLACK Uly for off road riding. I did about 200 miles of desert last week, what a hoot!. I am considering wiring the exhaust valve open, I know I will loose a little low end torque but do you think I will get the desired results with little or no ill effects? | ||
| Stevem123 |
I doubt it. The engine needs a little more backpressure for the low end. Locking the valve open would be better for the top end of the RPM range and your lower RPM's would suffer performance loss IMO. BC Steve | ||
| Paul56 |
Doubt that it would hurt anything and it just might detune the bottom end a bit. I'm going to tie mine open just to see if the fan runs less. Even on ~40 degree mornings it's on after 35 miles of 60-80 mph commuting. | ||
| Larryboy |
i had the valve tied open for a coupla days before i got it into the dealer for a new servo. it seemed worse down low with the surging and my gas mileage dropped to 29mpg. | ||
| Buelldyno_guy |
No the Dyno I cannot see any gain either way. I have been told the valve was to help a noise issue, and that just happend to help the engine rev quicker. I ran mine for an hour or so watching the valve and the dyno data. I could not tell all I ever saw was the valve cycle and could see a blip in the data when it did. I had been hoping that it modulated, but it works just like it states in the owners manual, just open,closed or closed,open. ... Terry | ||
| Chadhargis |
So, are you saying it doesn't offer any power enhancement. Just noise abatement? | ||
| Thunderbox |
My Uly had a malfunctioning valve from the factory and I swear the low end felt very week until the valve was changed. I didn't notice anything up top but then I don't ride my bike up there very much. This was seat of the pants dynoing so no real scientific evedence. | ||
| Stevenknapp |
Service manual says that it opens at two times: - High RPM - Low RPM at WOT I'd assume the dyno runs were done at WOT, where it would probably already be open? Where on the street you're not WOT much and it might be closed? | ||
| Odie |
Valve opens at low rpm to allow engine to spool up quicker; closes mid-range to help build torque; opens at the top end for more top end power...... | ||
| Chadhargis |
So...the million dollar question is why does the Buell race muffler, Drummer, etc. not use the valve? I'm a big torque fan, and I want all of it I can get across the rev range. I do spend most of my backroad riding time above 4,000 rpm and not a lot of time below 3,000 rpm (since that's where the bike starts to get the "shakes"). | ||
| Aeholton |
This is an interesting discussion. I was actually considering installing a Race ECM since it runs richer. However, I wasn't financially ready to buy a new pipe. Therefore I was just going to lock the interactive exhaust valve in the open position. My guess is that it still isn't as free flowing as a race exhaust. The end result would be richer => possibly less pinging and cooler operation. Anyone else have any thoughts on this? | ||
| Thunderbox |
I don't see how it would cause less pinging. The pinging happens when the air fuel mixture propagates to quickly in the cylinder and this occurs when the exhaust valves are closed. It may make the engine run a bit cooler. I don't know if you want it cooler as the fan regulates engine temp where it is supposed to be. Drummer gives benefit down low so it is tuned to that RPM area. The race muffler is just that, RACE, so if you want a machine that performs better at high RPM go for the race muffler. |
