First, "backpressure is a myth. This old-wives-tale needs to die an horrible death. Those who spout and spread this myth have never tested it. And the internet has allowed it to spread like a virus.

I have tested it and stand by my previous statement. I've read through numerous old and new posts on this forum and have seen where you've been nothing but helpful. I'm not going to argue. I only wanted to help provide the op some perspective on "straight pipes" and the importance of a tune.

Gary
 
back pressure

Tripp has said what I think is one of the few true things on the internet. Back pressure to me, is when ones spine hurts. I can and have tuned many bikes with open pipes(seem to be a favorite of Harley owners). They can run smoothly ( if fuel injected) but don't make the best power, normally they are just loud. I did a guys Sprint a while back with an exhaust he made. He liked the look of it, thats fine it is his bike. It made 74hp... He said he didn't care as he wanted the look. Thats good to. About a year later he sold it becuase it was gutless and the next owner brought it back because I had wrecked the tune and made the bike slow. I got him to put the previous exhausts on and it made 122. Exhaust flow and harmonics are confused with back pressure I am sure. Back to the question, you have a bunch of sensors etc on your R3 gathering info and the ECU is then telling the injectors and ignition what to do. The ECU does not know you have fitted a different exhaust pipe and air filter, some-one needs to make adjustments to it so it can compensate for what has happened. Off to do some of that now, cheers :)
 
First, "backpressure is a myth. This old-wives-tale needs to die an horrible death. Those who spout and spread this myth have never tested it. And the internet has allowed it to spread like a virus.

Second, "Volumetric Efficiency" is mostly misunderstood and incorrectly calculated. Actual measurement of air and fuel mass trapped in the cylinder(s) needs to account for cross-flow out of the cylinder. As well as intake and exhaust reversion. Most do not do so. Thus most VE numbers quoted are WRONG.

TEST, test again, and then test some more.

How many top fuel dragsters don't have straight pipes? I read they do 0-100mph in less than a second. At 4 g's? How is that possible?
 
How many top fuel dragsters don't have straight pipes? I read they do 0-100mph in less than a second. At 4 g's? How is that possible?

Because they are not using the harmonics of the exhaust system to aid induction. There's a f**cking great pump forcing fuel/air in - all the exhaust has to do is get rid as quick as possible and away from the bodywork.
 
How many top fuel dragsters don't have straight pipes? I read they do 0-100mph in less than a second. At 4 g's? How is that possible?

Nitromethane has 462% more potential output than pump gas.
The "Zoomies" are directed to aid in downforce, which is more important than output at these levels or performance.
 
Tripp has said what I think is one of the few true things on the internet. Back pressure to me, is when ones spine hurts. I can and have tuned many bikes with open pipes(seem to be a favorite of Harley owners). They can run smoothly ( if fuel injected) but don't make the best power, normally they are just loud. I did a guys Sprint a while back with an exhaust he made. He liked the look of it, thats fine it is his bike. It made 74hp... He said he didn't care as he wanted the look. Thats good to. About a year later he sold it becuase it was gutless and the next owner brought it back because I had wrecked the tune and made the bike slow. I got him to put the previous exhausts on and it made 122. Exhaust flow and harmonics are confused with back pressure I am sure. Back to the question, you have a bunch of sensors etc on your R3 gathering info and the ECU is then telling the injectors and ignition what to do. The ECU does not know you have fitted a different exhaust pipe and air filter, some-one needs to make adjustments to it so it can compensate for what has happened. Off to do some of that now, cheers :)


Now thats what im talking about. a good bit of advice that must be listened too.

Oh and I like the back pressure info! LOL
 
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