Exhaust question for Pat................

[elmosisu]

I know that when you had your R1150r that you used A Supertrapp, in combination with a Y-pipe. I am now going to have that combination ( y-pipe should be here Monday) And I'm wondering how many discs you had in the 'Trapp ?? Mine came with eight, but I'm thinking that I may want more.......

thanks!

[Pat]

Lemme try to run this down to you in a way that it can make sense:

The bike ran ABSOLUTELY FANTASTIC with only nine discs and a closed
end-cap. Then I had to go and mess with it.....
if nine is good, fourteen and an open end-cap must be better....
- NOT! -

If I'm not mistaken, the below displayed Dyno run was with about
15 discs and an open ("off road/racing") end-cap.
It looks to me to be running a bit lean, and it was pretty danm peaky.....
hitting that rev' limiter much too easily.

I believe I settled on either 12 or 13 discs and the closed ("street")
end-cap. The bike ran fantastic for me, but keep in mind that I was
riding it like I was participating in my own imagined GP race. It was
peaky, and stumbled/surged/bucked a little around town at 'reasonable' speeds.

You will find that 8 discs will afford you really good low-end, GREAT mid-range,
and take you comfortably to the rev' limiter. It should be smooth, and
deliver linear power, while belting forth a little noise that won't
embarrass you or the neighbors.

There you have it! Go ahead and buy yourself a pack of 6 discs and give
it a go. But I think you might be juuuuust fine with your 8; if you want to
save some money and have some fun..... just buy an "off road/racing"
open end-cap and run THAT with your 8 discs.....

[dilligaf]

Hey Pat, just wonder'n.......
How'd you get someone to dyno your bike at 1am! Was it by 12pak or gun point?

[Pat]

Modesto Ducati has his Dyno set up in a HUGE trailer. He rolls it out of the back when he needs to do a Dyno-tune. I try to catch him when he's got it rolled out and set up, paying as little as $25/$30.00 for a quick run.

Soooo...., it runs on generators; I guess he failed to set the clock. He also has it set up to "SAE" as opposed to "DIN" for a more realistic read on horsepower to the rear wheel.

(I can't post this much without inserting my obligatory, "I soooo miss my Roadster!" I can only hope that the new R1200R will be inexpensive.)

[elmosisu]

Okay....... now I'm hooked............Sebring Y-pipe and Supertrapp (AdventurePipe) with................

NO DISCS




that's right............ the whole disc pack is not in place. Just the inner baffle and packing. It's like a Glass-pack. Straight through.

It sounds like a nasty WWI bi-plane, and runs REALLY GOOD!

I have a Techlusion, with the pot settings towards the rich side on the green transition pot, and this bike moves out!!

I'm going in to dyno it in the spring, and will ride it during good weather spells, but so far.........I've pinned it to 125mph and it runs like the wind!

Did I mention that it's loud?

That's what earplugs are for, I guess.

Cheers

[Pat]

DANGER!

I had a custom can made for me that required NO packing. I told him to
keep the baffle in place, but not to pack it. It was about the same size
as my SuperTrapp, carbon fiber, and sexy sounding. In fact, it sounded
like the single baddest Honda RC51 V-twin EVER MADE making a pass at
150 mph!!!!! "Orgasmic sounding" may not be strong enough to describe
the sound AND performance!!!

I began my ride home some 60 miles away, and had a baaaaad feeling
about the way the bike was performing. It ran like a scalded cat at high
rpm's, but lacked everything (except noise) at the low-end. Half-way
home, I pulled over to put my ear plugs in (reluctantly). As I stepped
away from the bike to look at the new can that transformed my bike, I
could see more waves of heat drifting silently off the engine than I was
accustom to seeing. I had a bad feeling, and chanced a ride to the
Ducati dealership another 40 minutes away...... hoping he had
the Dyno with it's Air/Fuel snifter set up.

Cutting to the chase, I was bumping out some serious horsepower
figures, and running so lean...... that I was virtually melting my engine.
The ONLY speed that I was not running dangerously lean at, was speeds
in excess of 90 mph!

Put those discs in, no more than 16, WITH the "on-road" closed end-cap!
I fear that you may be doing some serious
damage to your engine!

[elmosisu]

I hear ya Pat............but


Did you have any FI mods ( Techlusion or Power commander) to Help with fuel delivery?

Wouldn't the motor start pinging first if it were becoming to lean?

Doesn't our intake system restrict flow to levels that would keep lean conditions under control?

wouldn't the FI system also add fuel if it was required?

I ran my bike for about 90 miles last weekend, and noticed no changes in heat output or driveability under all condidtions.

I'm just trying to keep all possibilities under consideration.

I'm putting in a correspondence to Techlusion to see what they think, as well.......

Rick

[Pat]

All that I had done was replace the factory air filter with a K&N element.

As I understand it, the fuel injection system on the 1150's is of an old, old, old design! In addition to being an outdated design, it's limited in what it can do and especially with what it's been given to do it with. In other words, there are OTHER -WEAKER- links to the equation that may prevent enough gas to be delivered to your needed ratio.

I'm no mechanic, I can only offer you my experience. And given what I've read here and the results of my own messing around with the exhaust, I would strongly advise that you STOP riding your bike until you get an air/fuel reading.

[boxermania]

elmosisu........technically speaking it is very difficult to lean out a boxer engine by removing the cat converter and adding a can. The reason for this is two fold:

1) The ECU has a small range of adjustability and will try to make up for the diference in the A/F ratio, specially in the closed loop (steady state ridding conditions)

2) The airbox presents a restriction to flow and no changes have taken place here

So in the real world, with exhaust mods, the ability to empty the cylinder has been enhanced, while the abiliy to fill it remains the same with the exception of the small fuel adjustment mentioned above.

I have run a SuperTrapp for a Buell, with 2.5" inlet and anywhere from 12 to 16 discs along with the Techlusion at factory settings with the OEM filter and recorded 84 rwhp at the Dyno, the torque curve lost a tiny bit at the bottom but exceeded the prior value at the midrange, ith the hp at the top. The bike ran beautifully and returned 42 mpg.

At this point in time I'm probably the only one with an R running the folowing set-up: no airbox, UNI Pods, K bike fuel regulator, Techlusion, TBR cat eliminator pipe with oval can and Autolite plugs. The plugs read great, the bike runs the strongest it has and returns ~ 45 mpg.

Hope this helps.........

[elmosisu]

That makes me feel a little more relieved. I respect Pat, and his experience as being of great value to me and the board, but I'm in need of some more input on this issue before I panic and remove my wonderfull sounding, new exhaust.

I've created a Forum message in the Techlusion website in the BMW section for Chris ( the Techlusion Guru), and I'm hoping that he will have some input on this that could clear up any questions


Thanks again!