How much can the stock pipes flow?

[Tripps]

Thinking of it as a pump, if your output hose is a certain size and you don't change it, then change the intake hose you won't see any gains in flow if the stock output hose was already the restriction. That's the case on stock rocket's.

Not really true, it will limit your gains, but you can certainly see gains. Turn your garden hose on half way, then open it all the way, big difference.

 

[Rocket3Pilot]

No, the intake changes without anything else changed on a Roadster, with appropriate tune are a LOSS in power, and I have the dyno time to prove it.

Everywhere under 5k is a LOSS in torque, the higher the RPM the less power is lost. On the bottom around 2k RPM it's a 20ftlb loss. By redline it makes right around the same as stock intake did.

With the power Tripp tune, I put down 126 on a bone stock Roadster, on the same bike, same dyno it did a 127 with triple K&N filters, but that only tells the peak HP story, the torque under 5K was a notable loss, area under the curve was badly changed.

That said, as soon as you put on TORs and the smooth cross over pipe the triples are a net gain in power, and very much worth it.

Edit: it's not an increase in fuel needed at lower RPM after doing the intake, it's a reduction, the length of the stock intake helps flow at lower RPM and the stock tune becomes too rich. At higher RPM a little fuel helps, but not much is needed with stock exhaust.

The box underneath is a hold over from the original cat placement when it was there instead of inside the muffler's.

I have to disagree with the net loss theory. I just did this on my 2013 roadster, bone stock. Simply added Ramair and there was no change in power either way up or down, just more noise from the intake, but the instant I opened the secondaries and copied the I3 values to I2 and I1 it was a significant jump in torque literally. If I time it right in first gear it will come up off the ground and occasionally, in second gear too.
Also, if your analogy was true the carpenter 240 kit bike could not make 195hp, it could only make 126hp because of the stock exhaust?

 

[Claviger]

When you all have done before and after dynos with stock exhaust the SHOW the power loss come back. I do and lost torque across the lower and mid RPM range while maintaining the same Peak horsepower indicating that yes it flows at least as much as this stock intake at high RPM. But it also shows that the stock intake assists filling the cylinder at Mid and low RPM. This is why the stock intake is as long as it is rather than ending under the tank with an air filter fitted.

A carpenter bike using the stock exhaust will make more power than stock because it's an entirely different head and cam package and does not rely on the Scavenging of the exhaust to increase power which is what you're doing when switching to aftermarket headers to increase power on a stock internal bike.

All that said, the stock exhaust CAN make 500hp, just takes a 700hp supercharger setup strapped to the bike, doesn't mean it's at all efficient, when working with NA, you start with the biggest restriction, then the next biggest, then the next biggest. The stock Rocket restrictions, in order, are secondaries, exhaust, intake, cam, head.