2 Into X into 2 Exhaust

I've started the job of creating a replacement exhaust for the Green Trackie. I love the idea of a BOS type system but using an ohlins Shock, I can see the tyre hitting the pipe or the exhaust cooking the shock reservoir.  So this is what I've come up with so far. See pics.  The intention is to keep it as a two into two system , but instead of a H type cross over, an X pipe with be fabricated.
Q : Should I try to keep a loop in each separate pipe under the gearbox to emulate the removed pretzel ?

[You must be registered and logged in to see this image.]

I think you should buy a CBR600, Oh hang on, too fast for an old fart like you.
Try a CBR250

You know I'm going to into FIG mode and pontificate about mapping, so I have question.

Question number 0: Do you care about low/mid torque, or just want all the horsies above 6000?

The length of the system and the place of your X will move torque up and down the rev range.

I want the torque from 4500 and up , rarely below that range

You won't need a bend like the stock pretzel, but try to get two bends in. Maybe something like the Arrow midpipe.


[You must be registered and logged in to see this image.]

Something like this ? the U-bends are quick and easy . lobster back bends are cool to make but very time consuming. The upper header pipe is the shorter of the two at 785mm ( around the outside) right header is 920mm. using the u-bends as shown will help even the lengths, then through the X to the mufflers. upper muffler is set back a bit to further increase the left pipe length. The pipe I'm using is smaller than the headers BTW, 1 3/4" O.D.

[You must be registered and logged in to see this image.]

Is the length of the Ron-pretzel more than the factory pretzel? If so, you'll probably end up with a slightly broader peak torque band, but maybe peaking a tad higher due to the X location. That's what my arse tells me.

That works for me

The Zorst work begins. I had to go with lobster back for the tuck-in behind the gearbox to gain boot clearance. 3 1/2 hrs to cut and tack weld, I love doing this but gee-zuzz it takes some time.

[You must be registered and logged in to see this image.]

Do you not have a 'Job' you lucky bastard!

Job? He's got a tribe of serfs and plebs that make him millions while he plays with his toy helicopter and aeroplanes. As in 1:1 scale.

Crivens! What happened to your thumb and pinky?

Wayne speaks with forked tongue. The guys at work don't need me watching them on quiet days, I can worry about work equally well at home. GRiSO work is a kind of therapy

Finally figured out a way to get the X cross-over in the system. Hope to have it done and test run today

[You must be registered and logged in to see this image.]

Not finished yet , but almost .......
[You must be registered and logged in to see this image.]

Wow, great work Ron.

I like your style! Keep us posted.

G'day Ron
Thanks for posting your project, very interesting, like your skills and jealous of your equipment ....
I will be interested to see what happens with the exhaust flow at your cross over, will one cylinder gas flow heading straight forward have an effect on the other ? Will some sort of back pressure on the other be created ? Or will both get jumbled up at the cross and cause back pressure on both ?
This is going to be interesting .......
Have a great day

Nice work, anxious to see the finished product.

Some more pics. 99.8 % completed now, muggins here forgot the spring attach loops to secure the mufflers.  The O2 bungs ugly it up a bit, this was the only place I could fit them.    Track days this Saturday and Sunday. Wiring up an Innovate data logger tonight, only a single channel so can only log one side at a time. Beetle - TPS and the negative side of the ignition coil is all I need correct ?

[You must be registered and logged in to see this image.]

Yep.

Fuken Awesome Ron!

Shoot some video. I want to see AND HEAR that sucker in action!

Great work.