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Discussion Starter #1
Please correct me if I am wrong.
Why are the front and rear VEs different?
Even though they are not identical I would assume that the VE of both are very much the same, then why do we have different VEs?

One answer would be that this gives us the option of tuning one regardless of the other, which is perfectly OK with me, but why are they different right from the start? Shouldn't they be the same and then we fine tune off that?
Would nt it be wise to take the max VEs at each range of each cylinder and create a new table with the max VEs for both cylinders, in other words equalizing the VEs to the max on both?
To further explain the previous thought....
1) Take the front VE and paste it into Excel
2) Take the rear VE and paste it into Excel
3) Create a new VE table in which the value for each cell is the highest value that either cylinder has (if the front is 98 and the rear 101, take the 101 value)
4) Take this new (equalized and optimized) table and copy it into the front and rear VE tables.

Doesn't this make sense?
 

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On a twin engine with side by side pistons, yes. A V twin is like having 2 seperate engines. They do not fire 360 degrees from another they fire 315 or 405 degrees from the other. The rear cylinder is almost a "helper" cylinder, just look at the connecting rods. The rear cylinder gets hotter because of location and both cylinders have different (durations?) since they fire differently, the exhaust in the header has a different pulse for front and back. You might as well have 2 different engines with odd characteristics.
 

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Good explanation Paul. The shared intake adds to their differences as well. Intake and exhaust pulses cause the two cylinders to definitely NOT act the same, ie: share same tables.

When I had my bike tuned, Bob went through every square. He stopped -- I thought he was done -- the bike was running pretty good but not as smooth as I had hoped. Then he changed the sniffer & said, "Now let's do the rear cylinder!" Man, when he was done that puppy dog smoooooooothed right out, and the torque curve took on a nice shape.
 

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Discussion Starter #5
Where can I contact Bob?
I live in Dominican Republic (i.e. Alex Rodriguez, Sammy Sosa) and we have no dyno, no nothing...
Will he be willing to share a map for my setup?
 

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Bob is in Hayward, CA, USA (RC Cycles). I guess you could find someone with a map close to yours & try it -- I don't know how that works but I wouldn't ask a professional tuner. Doesn't your SERT come with a canned map fairly close to what you're running?
 

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emxgarcia said:
Where can I contact Bob?
I live in Dominican Republic (i.e. Alex Rodriguez, Sammy Sosa) and we have no dyno, no nothing...
Will he be willing to share a map for my setup?
Here 's your best solution without a dyno. It will cost you some cash but there is really no other way to do it.

Otto and I will come up with a proper spark advance curve that will be close and we will give you a correct main AFR target table. Then you will need to have someone there weld in two 18mm x 1.5mm O2 sensor bungs into your head pipes about 3 inches from the exhaust flanges. Then go to the Daytona TwinTec website and order the TwinScan II with the optional WEGO IId accessory. Follow the instructions on installation and proper use and then record data on what it's doing and modify the VE tables as multiple trips down the road in different throttle regimes will reveal. The TwinScan II software provides data that directly translates straight into the SERT VE tables.

This method works great and will get you as close as possible without a dyno session.
 

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Discussion Starter #8
I wholeheartedly appreciate the support but buy the TwinScan is not an option, today.
Having recently moved to a new home, the mere purchase of the SERT was sort of a wild act, so I have to go with the seat of the pants method.
So, having said that.... any tips besides what's on the manual?
 

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download a close map and then tweak it as the manual suggests.
 

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Discussion Starter #11
Here is what I fially did.
Thanks for the input to all of you.

I initially loaded the 105HD019 map which sounded like the perfect fit for my bike (see signature for details).
I spend 1/2 the weekend trying t get rid of a cough, hesitation etc to no avail.
Finally I decide to load map 105HP103 which does NOT take into account the SE-203 cams, and guess what? The bike ran like a dandy.

Then I took from there and lowered the AFR (for richer mix) to compensate for our poor fuel AND hot air. A couple of touches on the AE and DE tables and next thing I know I have a very smooth bike with no hesitation or stumble and the bike is ready to go at any throttle %.
 

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Discussion Starter #13
Well, I guess I got lucky and tried and tried until something decent came out.
This weekend going for a long ride (for an island 300 miles is long) and I wil see how it does.
 
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