Anybody know the history or development behind the twin pipe primary headers, (two pipes matching the exhaust ports)?
How do they compare to the stock header ?
Anybody know the history or development behind the twin pipe primary headers, (two pipes matching the exhaust ports)?
How do they compare to the stock header ?
Started out on the 1125, then the 1125rr, finally the 1190rr & rs models. Switched to the oval stamped front header on the RX.
The twin down pipe setup is a little smoother in physical form, but has less cross section volume than the stamped oval of the RX. Flow velocity would _possibly_ be higher but slightly restricted in comparison.
The RX oval style was more of a compromise to production needs, the twin tube style was just the design at the time.
The front header on the older models (twin tube style) were essentially symetrical up to a point (rear header is longer) and were the same diameter.
The oval style header is smaller than the rear on the RX by approximately .150" and is significantly shorter. Tuning it is a pain in the ass.
Is it worth persevering with the twin tube headers ? I aquired these with the bike all set up to race spec , but was a bit disappointed with the horsepower result. I have a tuneable ECU as well .Originally Posted by d_adams
What numbers were you seeing out of it? What bike is it on? Mods done to it?
The WSBK bikes produced decent power (200+) but they had a lot of extra work done to them. They used the twin tube design.
I was only getting 159 rwhp against another 1190 with tips and tuneable ecu getting 175, on the same dyno. I know numbers are only relevant to the dyno , but bike to bike or post mod numbers are what we look for. My bike had the pipes and muffler system as the WSBK bikes had and with the factory specific ecu . Not looking for 200hp as engine longetivity would be a worry . Other mods, race glass, rear shock, rear sets , quick shifter, brake pads, Brembo RC19 MC and gearing .
Mine has made 178.8 hp, but it's still what I'd consider low power since it was road tuned rather than dyno tuned. It runs a full point rich on the air/fuel mix, which is where my power loss is at. The best guess on it is 183-185 hp at the wheel if I could get ram air to work on the dyno like it does while riding it. It started out at 162 all stock. That's what you need to look at. What did it make in stock trim? If you don't know, put it back to all stock and run it again. It's possible the pipe you have simply doesn't make the power you are expecting.
Better -
Did anyone do any actual "tuning" ? Seems very low for a decent exhaust system and a "changeable" ECM. It would seem to me that a good amount (many hours, many attempts) of experimentation would be required to match the intake (1190's injectors, cams, heads) to that exhaust system.
I recall, when racing was done here at the Fontana raceway in SoCal, the numbers quoted were slightly above the 200 that Dean notes.
An upgrade to the cams heads (the new 1190 stuff), that exh. system and a "good" tuneup, should provide some good power numbers.
Mike
Anyone done any dyno runs with U4 or MR12?
I was using the ECU supplied for the twin pipe system, this was mapped at the factory and locked. I since purchased a tuneable ecu .
I would be concerned about detonation using MR12. Even stock, this is a decently high compression motor.
I ran T4 (MTBE) on my 1190 prototype motor, and it was insane -- I want to say the torque was above 100. The HP was right about 160, but that really doesn't tell the story like riding that bike did. The guy that bought it said he felt it pulled harder than the RX, and I agree, with that motor having better bottom end and a more usable power curve. It would dig out of a corner like the hand of God was throwing you down the track. The 1125r fuel pump had some trouble keeping up and would throw a CEL on very long straights.
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