4-1 vs 4-2-1 Exhaust

I tried posting this in Tech and got a lot of views but only one response so I"m gonna try it in Vintage. I notice Vintage is where most of the sage wisdom is anyway. I am looking for advice on a pipe upgrade for my 95 ZX6r. It has what I believe are stock headers and a D and D can, a Factory Pro 1.7 race jet kit installed and a Wiseco overbore piston kit with a fresh bore, all as of last summer. From what I understand about tuning/exhaust reversion, a 4-2-1 pipe is superior to the 4-1 insofar as eliminating a flat spot, usually just below the top 3k rpm. I have my eye on a cheap used set but wonder if I'm borrowing worry to try to upgrade when it's a vintage track-only bike that already makes 90 hp, and also, because of the configuration, if my current plastics will work with the 4-2-1 pipes. Thanks in advance for any information.

 

My understanding is that 4-1 exhaust favor top end HP at the expense possibly of some low/midrange.

 

My recollection is that the 4-1 arrangement offers more power at some rpms but produces flat spots in others.

Kevin Cameron has written about this subject comprehensively in "Sportbike Performance Handbook". Lots of other good information, too.

 

Sportbike Performance Handbook

It IS is a great book! That's where I got the idea. Kevin Cameron wrote that book so even I could understand the mechanical principals that make us go down the road, around corners, and stop at the end-and why we sometimes don't. I was looking for someone who made the switch from 4-1 to 4-2-1 to see what his experience was. Thanks.

 

Well these days if you look at most (i.e. >90% of OEM bikes) they come with 4-2-1 exhaust, and by most I mean your typical I-4 configuration of course.

Yoshimura special order race system come in a 4-1 setup for instance, but you have to pay more for them (like the hotness on Mladin's bike down there). The typical off the shelf stuff is 4-2-1

 

My understanding....4-2-1 for streetability/convenience. 4-1 for the most power.

 

Ok DO NOT USE A 4 - 1 on this bike. been there done that. Use a D&D pipe or a Hindle with a factory jet kit and you will be happy. 4-1 will make it hard to ride and have a flat spot right around 7500. Used both the D&D and Hindle and you cant go wrong. never used the Muzzy. Hope this helps.

Steven Isenhower #52 2001 V-6
2nd Sucks Racing
281-536-3330

 

So you had a 95 ZX6r with a 4-1 pipe and switched to a 4-2-1? What was the improvement, no flat spot?

 

night and day. BIG flat spot, Smooth the power out and made all the difference in the world.

Steven Isenhower #52 2001 V-6
2nd Sucks Racing