| Author |
Message |
    
Js_buell
| | Posted on Saturday, September 19, 2009 - 05:41 am: | 
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Ericz was the chain mod necessary or it was just because you prefer chain? |
Ericz
| | Posted on Saturday, September 19, 2009 - 05:02 pm: |
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Originally I converted to chain for a taller final drive ratio. I really liked the belt but didn't have that option. The stock ratio made for 1-2- & 3rd gear wheelies. I don't mind the front wheel coming off the ground, but in 3 gears is too often! It is better now with the taller ratio and longer swingarm. |
Blake
| | Posted on Saturday, September 19, 2009 - 11:16 pm: |
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Eric,
If you can take a pic of your turbo mounting scheme, I'd be happy to critique it from a stress analyst's point of view. 
The beauty of the OEM mounting scheme is that the suspended mass is clamped hard to the vibrating engine, so there is virtually zero relative motion between the two. If you swap that hard clamped scheme for a suspended/hanger scheme, even 3/16" SS bracket will allow some pretty frightening vibration to manifest between engine and turbo and it can easily lead to crack propagation and fatigue failure. It's not an intuitive failure mode at all and you can end up chasing it all around every which way trying to resolve it.
Buell found the one true optimum answer to the issue, clamp the muffler tightly to the engine/tranny so that there is no differential vibration between the two.
Do you recall all the issues with the old tube frame exhaust systems, especially aftermarket mufflers? The cracked and failed race exhausts?
I'd be happy to advise. |
Biggie
| | Posted on Sunday, September 20, 2009 - 12:47 am: |
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WOW that is the baddest looking & sounding buell I have ever seen and heard.
I would LOOOOVE to see/hear a fly by video. |
Greg_e
| | Posted on Sunday, September 20, 2009 - 06:37 pm: |
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Please forgive if this was covered in a previous post, I didn't read the entire thread...
Any problems with the stock cam and intake to exhaust overlap? I would have expected you to be blowing a significant amount of air/fuel out the exhaust valve with the stock cam. Or am I wrong thinking that there is a bunch of overlap?
Also since you are kind of running out of room with the stock ECM I would suggest a MicroSquirt or a MegaSquirt controller. That would give you a better granularity in the fuel maps, as well as a second MAP to read ambient pressure. If you really wanted to get into it you could put on a MAF to get more precision.
When I get a bike I plan on doing a Microsquirt upgrade to it, though probably not a turbo. RAM air induction might happen though, should be good for a couple pounds boost up at speed.
(Message edited by Greg_E on September 20, 2009) |
Bombardier
| | Posted on Sunday, September 20, 2009 - 09:12 pm: |
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I have contacted the developers of the DDFI system in the past and they did say that the vacuum port on the TB could be used for a MAP sensor but in their opinion the TPS was a better option.
Is it very difficult to include the MAP sensor as the primary tool rather than TPS? |
Greg_e
| | Posted on Sunday, September 20, 2009 - 10:01 pm: |
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From reading on the Megasquirt, MAP and TPS are important. MAP tells you what it really happening in the intake with engine load, and TPS tells what is changing or if it is wide open (and may have a different curve at wide open).
But neither is as accurate as a MAF sensor, which is why most cars use some sort of MAF (and still have a TPS and usually a MAP too).
Safe to say that FI on a bike is still pretty crude compared to FI on a car. Probably has to due with the amount of room available on the frame and engine. |
Phelan
| | Posted on Monday, September 21, 2009 - 01:28 am: |
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I'd say that's true to an extent, but there are some pretty amazing EFI systems on bikes out there, like the later Delphi systems on the HDs. It would be nice to see an EFI on a bike setup for a secondary fuel source (conjunction) like hydrogen. |
Blake
| | Posted on Monday, September 21, 2009 - 06:19 am: |
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The pressure in the intake manifold varies like crazy in our Buell engines; every time an intake valve opens or closes the incoming airflow is being disturbed. Think of it more like lungs than a vacuum cleaner. 
Because of that I think it would be tough to use a MAP in place of a TPS. |
Greg_e
| | Posted on Monday, September 21, 2009 - 10:19 am: |
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There is some discussion on this on the megasquirt and microsquirt forums, it requires that the MAP is sampled at a different time (just before the squirt) so that the airflow and pressure are at the correct place in time. I don't know the specifics because I haven't studied the issue yet, but I certainly will if I can find a bike near me. |
Buford
| | Posted on Monday, September 21, 2009 - 12:54 pm: |
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Blake..would that variance account for the less than perfect idle? Tried adjusting timing, af ratios etc and mine idles fairly well at approx. 975 rpm but it still has that miss fairly often. |
Ericz
| | Posted on Tuesday, September 22, 2009 - 10:00 am: |
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I have not had any problems with the extended overlap of the stock buell cams and my turbo setup. I do think that a more turbo friendly cam grind would help with everything but I have been working to push the stock motor to see what it can do.
The vacuum port on the stock Buell TB is before the throttle plate, so any MAP reading from there would only give you airbox pressure and not intake manifold pressure. I had to add a port to the TB below the throttle plate for all of the vacuum and pressure differential operated components i.e. blow off valve and vacuum/boost gauge.
H-D Delphi systems use MAP sensors to manage fueling to the motors and they work out well. The inconsistent intake manifold pressures during idle and low rpm are hard to conceptualize for myself but it seems like everything is programmed just right for the Delphi EFI systems. |
Greg_e
| | Posted on Tuesday, September 22, 2009 - 10:44 am: |
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How are you dealing with the air fuel mixture? If you are using the stock O2 sensor I would expect it to be very much wrong from the fuel blowing out during overlap(reading rich which would mean the fuel table altered to be more lean). If you are dealing with just volumetric tables and ignoring the O2 then things are probably fine.
Ultimately I would expect better performance in the boost section with a turbo friendly cam, but you would probably lose performance in the non boost parts.
Do you have a picture of exactly how you made the vacuum port in the manifold? Regardless of boost/no boost if I ever manage to get an XB9r I plan to go ahead with the Microsquirt conversion which will really require the vacuum port in the correct place (downstream of the throttle plate). |
Ericz
| | Posted on Friday, September 25, 2009 - 05:03 pm: |
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To tune the bike I can't begin to use the stock O2 sensor for a number of reasons -1- It is a narrow band sensor and can't measure much more than stoich. -2- The stock location is between the cylinder head and the turbo and either narrow or wideband sensor readings are skewed with the extra exhaust pressure under boost.
I have done all of the tuning on a dyno using a wideband sensor after the turbo.
The 02 sensor actually reads leaner than the combustion burns because it measures the oxygen content of the exhaust gas. With the high overlap, more unburned intake air flows into the exhaust, which increases the oxygen content of the exhaust gases and makes the sensor read leaner.
I couldn't find a pic of the vacuum port but it is an aluminum 1/8" NPT bung welded to the left side of the manifold just downstream of the throttle plate. I have a 90 degree barbed brass fitting threaded in with silicone vacuum line attached. |
Greg_e
| | Posted on Friday, September 25, 2009 - 06:43 pm: |
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OK, thanks. I was thinking I might get an aluminum barbed fitting that threads into the manifold. |
Blake
| | Posted on Saturday, September 26, 2009 - 12:24 pm: |
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Seems likely that optimally timing the MAP sensor reading would work. As Eric points out, it certainly works for the the H-D systems.
Interesting stuff. |
