EXACTLY you only use partial throttle for cruising and the stock exhaust works great for that purpose so if thats all you care about leave the bike stock it has all youll need or want for that purpose .
 
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Indeed it does, but it sounds like, .......... well I was going say shiet, but truth is it doesn't sound much at all. Which does suit many people.
JUST a SLIP-ON muffler solves that problem and eliminates everything from the header back for a big weight loss and a low restriction great sounding pipe that works great as I am running that setup on my 09 CLASSIC . AND leave the air intake stock for cruising you dont need more top end airflow
 
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@barbagris Thought I would use a small (1 or 1-1/4"diameter x 3 or 4" stroke) Bimba or similar air cylinder for the task to start with. I can get these used for almost nothing. Connect the hose from a tee to the closed end of a double acting one (these have seals that energize in both directions) and then use a sleeve over the rod and against the cylinder rod end cap. The sleeve will prevent the rod from retracting under vacuum. Change the sleeve length and you change the "accumulator" volume. Once you know it works and the volume you desire, then make a CF version and place it inline. Let me know how it works. Will save me the trouble of experimenting, thank you. (Watch the fluctuations in coil saturation times, and document the changes in MAP for a given rpm, as well as how it feels for a given volume, please.)

As to exhaust systems: Anybody who says a stock Rocket exhaust, with or without an aftermarket muffler, is the same at a steady speed as a good header, and that said header has value only at WOT has never seen what happens to exhaust gas composition and heat with changes in scavenging and back pressure. Nor does their butt dyno function well.

Headers make a difference across the entire operating range; idle to redline, and 1% to WOT. The degree of difference changes, but they do change how the engine functions. (Why else would a different tune be needed to make the engine run right after an exhaust change.) And some headers are much better than others during transitions of throttle and rpm. So, a header that makes the most peak horsepower at steady rpm, can be and most often is slower at the 1/8, 1/4 or 1/2 mile run than a lower peak horsepower header that has a torque curve that compliments the gear changes AND the changes in acceleration rates as you move from 1st to each subsequent gear.

I would suspect that most of the R3 owners on this forum who have purchased a good header from the several brands that have been or still are available would testify to the improvement of much of the operational range and not just WOT.
 
@barbagris Thought I would use a small (1 or 1-1/4"diameter x 3 or 4" stroke) Bimba or similar air cylinder for the task to start with. I can get these used for almost nothing.
My idea is two CF tubes. One 35mmID the other 34.8mmOD (32mmID) About 3" long each. Each capped at one end - I'll use carburettor vacuum lines and stubs - By sliding one sleeve out a bit and using some goo to seal/fix - I can vary volume. So the ideas are not that different.

Would you add any internal damping? - Filter foam for example. My plan was to see if the AFR curve smooths out. Need to work out if I can log MAP. Using "Torque" maybe?

This how the AFR curve looks currently. Raw data available if anybody wants it.
sundazrungraphs.PNG
 
IMHO, because the Rocket needs so little throttle for normal speed street riding, the MAP and throttle position sensors are too "coarse grained" to adequately control AFR, especially when un-restricted and the timing tables are changed accordingly. The difference between 2% and 8% in throttle positions in the Rocket is vastly different than in a 4cyl Nissan automobile, which to equal the desired response is probably close to a 25% change in the Nissan. Add to that a lack of a plenum, which adds volume reducing the pressure fluctuations between an individual cylinder's valve opening events and then between cylinders' valve events. The sensor and ECU have more time to measure and respond to averaged pressures in a plenum than the real time pressure changes in a single TB runner. Hence, any deviation from normal in the Rocket's TPS's operational characteristics is felt immediately by the rider and shows up in AFR deviation, where as in the Nissan a similar change isn't felt at all.

Sometimes, I ride at steady slow speeds one gear higher than I care to just to reduce the sensitive, even twitchy throttle response (in part due to very rapid AFR changes.) One of these days, time permitting, I am going to add an adjustable volume accumulator between Map sensor and the three-way hose tee. By buffering pulses between cylinders, the Delta P processed by the ECU will be reduced. It will be an interesting exercise.
LET us know when you iron it out .
 
@barbagris No internal damping; the small hose relative to the accumulator volume will do that just fine and react predictably whereas foam adds another variable.

My intent was to dampen primarily at 1% to perhaps 3% TP at steady state running. The idea may work further into the rpm band too. However, as soon as you have rpm and throttle position changes occurring, the ECU will add an enrichment algorithm going up and a decel algorithm going down (and ignition timing likely changes as well.) These get complicated because with a steady TP and increasing or decreasing rpm (load changes) they are active too. They will react to the Delta so the fixed volume will be a compromise that may negatively impact the AFR during transitions. We are trying to apply a "Band-Aid" here as getting into the ECU deeper and changing algorithms would be much preferred. Therefore: "Do No Harm."
 
Having done a good bit of logging on the R3, you log looks pretty normal. There's quite a bit of AFR swing during transitions. What I do is find a long flat road and do a sweep, using thr POD300 to monitor TPS, and get a steady throttle position log at various percentages like 20/40/60/80/100. 3rd gear works well for this. That'll get you nice tuning data so you can make your adjustments.

The transitions are a bit difficult on the R3, the ECU is a very rudimentary device. When the tables are dialed in right at steady state TPS, it should be close during transitions. The inability to adjust the acceleration enrichment is the #1 weakness of R3 tuning solutions, it means switching injectors sizes is slightly wonky.

Tuning the L tables will smooth the transitory states, it's far more time consuming than F Tables, and requires good data logging and time.
 
@barbagris No internal damping; the small hose relative to the accumulator volume will do that just fine and react predictably whereas foam adds another variable.

My intent was to dampen primarily at 1% to perhaps 3% TP at steady state running. The idea may work further into the rpm band too. However, as soon as you have rpm and throttle position changes occurring, the ECU will add an enrichment algorithm going up and a decel algorithm going down (and ignition timing likely changes as well.) These get complicated because with a steady TP and increasing or decreasing rpm (load changes) they are active too. They will react to the Delta so the fixed volume will be a compromise that may negatively impact the AFR during transitions. We are trying to apply a "Band-Aid" here as getting into the ECU deeper and changing algorithms would be much preferred. Therefore: "Do No Harm."
:thumbsup: @Speedy Understood. tbh this is a bit of an R+D thing for me. I'm not actually banking on it making much difference. You piqued my interest.

@Claviger (and anybody else interested) - Best solution I have found for acceleration enrichment is to map each gear differently. I have different AFR targets in 2nd-4th to 1st and 5th. Also use the secondary throttle plates (but not Triumph numbers) - F-L switch values altered. It's the area 0-20% TPS I want to look at. Especially sub 8%.

Also noticed before that the ECU logs a different Lambda state at times - and that's with a resistor plug in. That suggests to me an algorithm in the ECU.

PATIENCE PLEASE. By the time the bits arrive I'll be setting off to the UK for my hol's. Could be Oct before I have data.
 
"larger-radius, higher-flowing bends" this comes out of that article, which seems like a good article. BUT that statement is not true. Look up Micron exhausts ( from the past) and laminar flow concept and find out why.
For simpletons like me the last few posts of this thread re data logging etc exceeded by ability to comprehend but Micron do at least keep it simple. I'm happy with my CES but am prepared to to attempt a simple understanding of theory behind gas flow etc.

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My idea is two CF tubes. One 35mmID the other 34.8mmOD (32mmID) About 3" long each. Each capped at one end - I'll use carburettor vacuum lines and stubs - By sliding one sleeve out a bit and using some goo to seal/fix - I can vary volume.
@Speedy @Claviger - After some searching for material to do the end caps - They were machined up today - Delrin. Need to clean up the C/F tube ends to perfect 90° Ends will be sealed in with Loctite 545. Also have a way to measure vacuum fluctuations (I think). My camera is giving me trouble - so may be a day or so before I can do a photo.
 
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