Bucket lap records

[richban]

l'm on monteith's golden lager but not as good as yours

Same brand but Pilsner.

[crazy man]

Same brand but Pilsner.

thats like losing 2 hp

[richban]

thats like losing 2 hp

Spoz coz it does have 1 more %. Less back pressure though.

[Rick 52]

As its the first time we have had timing on at Tokoroa (I think)

Rick takes the honors with a 43.400

Cheers Rich
Still very pleased with the win let's see what this weekend bring ..

[TZ350]

Rick was realy riding the wheels of his bike, it would be interesting to have Av's times from the year before as it is hard to believe that anyone could peddle any faster than Rick was in that second race.

[all4A50s]

I don't understand the term back pressure. In theory I thought the muffler is only there to simulate the end of the exhaust system and send a scavenging way back to the cylinder while keeping it quite. Lap times have nothing to do with how loud a bike is, its the way the bike is ridden. Poor tuning will effect lap times. Not sure what you are getting at. There is know proving / or disproving. You tune to the rules and thats that. I am sure I could make a loud bike that made a little better power with an open megaphone but no point coz it would then be illegal.

My understanding is back pressure comes from introducing a restriction to the exhaust to create turbulance. This changes the sound/pressure waves effecting the scavenging.

[speedpro]

I always thought the "back pressure" thing was a load of crap. Then I built a bike and deliberately gave it some back pressure by fitting a Rajay exhaust pipe. It was a bit heavy but the back pressure perked the old Z1 up quite nicely.

The fact is that an internal combustion engine processes air and fuel passing through it and makes power. The more air and fuel that can be efficiently processed the more power they make. "Back pressure" will only reduce the amount of fuel and air passing through.

[koba]

It seems there is an incorrect assumption made somewhere here that a an exhaust is always restricted by effective muffling...

[richban]

My understanding is back pressure comes from introducing a restriction to the exhaust to create turbulance. This changes the sound/pressure waves effecting the scavenging.

By definition it is supposed to hinder performance. Adding resistance to slow everything down just goes against everything I aim for in making my engine more efficient. If your pipe is way worng to begin with then maybe it might work. I haven't seen any moto3 bikes with reductions in the pipe at the muffler. Anyway each to there own.

[all4A50s]

By definition it is supposed to hinder performance. Adding resistance to slow everything down just goes against everything I aim for in making my engine more efficient. If your pipe is way worng to begin with then maybe it might work. I haven't seen any moto3 bikes with reductions in the pipe at the muffler. Anyway each to there own.

The way I can make sense of it is to liken it to when reverse cones are added to the end of expansion chambers and the sound waves being deflected back, creating a vacuum which aids in the scavenging of the exhaust fumes.

After talking to other CBR racers I am finding these engines perform better with some exhaust restriction, regardless of the exhaust make up.

[Henk]

All I know is that when I've had mufflers fall off the bike usually immediately starts to run like a bag of poo. This may be because it wasn't set up to run without one to start with.

[cotswold]

All I know is that when I've had mufflers fall off the bike usually immediately starts to run like a bag of poo. This may be because it wasn't set up to run without one to start with.

Not a bucket but still relevant, I had my super trap fall off my buell last week and it ran like a dog, lost all its torques and felt awful. The super trap has a closed off end and breathes out through a series of rings. It is pretty damn quiet and is only 10"s long

[crazy man]

Taumarunui lap record my regan griffiths ....24.324
thought l better put this he's been going on enough

[richban]

Taumarunui lap record my regan griffiths ....24.324
thought l better put this he's been going on enough

Good stuff. Some will need to collate all this not sure how. Short laps on that little track.

[koba]

Good stuff. Some will need to collate all this not sure how. Short laps on that fast little track.

Fixed it for ya.
It really is a track that is all about keeping insane corner speed.