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Need a volunteer for dyno testing

Fred H.

Fred H.

Member
Member
Guhl Motors is still looking for a volunteer willing to bring their bike into his shop and let Don Guhl put it on the dyno and retune and reflash the ECU.

Ideally he would like to get both a stock 2008 and a stock 2010 model on the dyno. This will enable him to validate and fine tune changes to the fueling and secondary butterflies tables.

His website is http://www.guhlmotors.com/
(717) 618 4212

I talked to Don yesterday, and he has some available Dyno time, so if someone wants to take advantage of this, now would be the time. You'd end up with dyno charts on your bike and a free ECU flash.
 
C1xRider said:
Darn it.  It's just not worth the 2,335 mile one way trip for a free dyno run and ECU update... :(
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Yea, that's the same boat I'm in. I'd take my bike to him if it wasn't so far away. The best scenario would be to find someone local in Pennsylvania that could do it.
 
Fred, I might have reason to be in NJ later this month. Once that is confirmed and I determine I can ride down, and I determine I can hang around in PA for an extra day...I'll call Don.

A lot of variables, but we'll see.
 
Don never did respond to my e-mail, so I just called him.  I will be at his place this Friday, 11 June, if he doesn't go to Ohio.  If he does, I will be at his place on Monday, 13 June.  I'll keep you all posted.
 
Bob said:
Don never did respond to my e-mail, so I just called him.  I will be at his place this Friday, 11 June, if he doesn't go to Ohio.  If he does, I will be at his place on Monday, 13 June.  I'll keep you all posted.
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Glad to hear it. Though Friday is actually June 10th, not the 11th.
 
Fred_Harmon_TX said:
Bob said:
Don never did respond to my e-mail, so I just called him.  I will be at his place this Friday, 11 June, if he doesn't go to Ohio.  If he does, I will be at his place on Monday, 13 June.  I'll keep you all posted.
Click to expand...

Glad to hear it. Though Friday is actually June 10th, not the 11th.
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Yup.  Sure is.  I stand corrected.

Don and I spoke about what his approach is going to be, but I'm not sure I got most of the technical aspects.  If I understood him correctly, he is going to leave the ECO mode alone.  He wants to run top speed dyno runs to confirm (at least on my bike) what the actual top speed is.  There seems to be some confusion on that point.  He also said he needed to look at a couple of aspects of the stock maps especially with regard to the opening of the flys (I think that's what he said).  He figured his pre mod testing could take 1 1/2 to 2 hours. Add another hour or three of map mods and performance retesting.  I told him it didn't matter much how long it takes as long as I can ride it home! 
 
Don knows what he is doing, and I'm certain you'll be very happy with the performance improvement when he is done. I just wish I lived closer to his shop.
 
Any idea if he needs another tester?  I am actually headed out that way this weekend, and am only about an hour and a half away from Ephrata. 

I am picking up a new to me '09 C14 ABS this weekend, but it does have a two brothers slip on pipe.  It would definitely be a cool opportunity to get the bike tuned.
 
I'd suggest you call Don and speak with him direct. I know he wanted to do both a 08 or 09 and 2010 bike. I don't think he has yet had anyone take him up on his offer.

http://www.guhlmotors.com/Contact.html

Guhl Motors:
4126 Oregon Pike
Rear Building
Ephrata, PA 17522

717-618-4212
 
Don has a 2010 on the dyno today and is in the process of optimizing the maps for the secondary butterflies and fueling and raising the speed limiter on it.
 
Fred,

In you get a chance can we also look at optimizing the Fuel Shutoff on closed Throttle. I may not be using the right technical lingo, but I find the bike is very abrupt when gearing down of off throttle situations.
 
Stewart, I spoke to Don and he said they smoothed out a lot of the jerkyness by adjusting the fueling. The economy mode also appears to be totally unaffected, and works like normal. He also found that the fueling self adjusts based on input from the second throttle position sensor on the secondary butterflies. It appears Don now has a solid map for the 2010 that raises the speed limiter, adjusts fueling, and opens the butterflies sooner and further, but goes back to stock when in ECO mode.

I'll try to post some dyno charts shortly.
 
Here is the before and after the speed limiter was raised. You can see it shuts the engine down abruptly after 155mph.

original.jpg
 
Stewart said:
Fred,

In you get a chance can we also look at optimizing the Fuel Shutoff on closed Throttle. I may not be using the right technical lingo, but I find the bike is very abrupt when gearing down of off throttle situations.
Click to expand...

+1000!  Once I made a change to the exhaust, the abruptness of the engine responding to cracking the throttle became very dramatic.

 
Fred_Harmon_TX said:
Here is the before and after the speed limiter was raised. You can see it shuts the engine down abruptly after 155mph.
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Fred,

  What does the bottom graph represent?  Looks like an O2 sensor or A/F ratio.
 
I believe the bottom graph is lamba from the wideband 02 sensor. Don said he had a sensor malfunction that caused the wild gyration at the end of one of the runs.

The graph above is from a 5th gear pull. I believe more dramatic results will show up in the torque curve in gears 1- through 4, since the secondary butterfly curves for those gears are much more restrictive.

It will also be interesting to hear what the owner has to say about how the bike feels. Maybe he'll come on here and post his findings. I haven't spoken to him yet.

I'll probably be boxing up my ECU and shipping it off to Don next week and having it reflashed.
 
Is there going to be another dyno chart showing an increase in hp and torque. I hope I'm not the only one that was expecting more of a difference. Power commanders are getting a little more than the ecu mod appears to be. I know this was a 5th gear pull but 2hp and 1ft lb of torque isn't what I was hoping for. Any further info for us on that Fred or don.
 
Corpssgt said:
Is there going to be another dyno chart showing an increase in hp and torque. I hope I'm not the only one that was expecting more of a difference. Power commanders are getting a little more than the ecu mod appears to be. I know this was a 5th gear pull but 2hp and 1ft lb of torque isn't what I was hoping for. Any further info for us on that Fred or don.
Click to expand...

I was also a bit disappointed in the chart. Though I'm not sure it tells the whole story, since its bottom graph is speed and not RPM. What we really need to see is a 3rd or 4th gear pull with RPM on the X axis.

You also have to keep in mind that the performance benefit from opening the butterflies may not fully show up on a dyno chart. Since one of the main benefits you get from removing them is throttle RESPONSE. The secondaries act like restricting elements, and slow the response you get when you twist the throttle. So without a time element on the chart, you may not get the full picture. Though you should see some torque improvement.

I'm not exactly clear on how much of a change Don made to the fueling. He also didn't open the butterflies up all the way, he just adjusted the map and slid it a few cells to the left to make them open sooner. The trick now is to finding the optimum point where you don't open them so far that you reduce intake velocity, but open them far enough that they aren't acting to restrict airflow. There probably is still more room for improvement.

It will be interesting to hear what the owner has to say. From what Don told me, he was grinning ear to ear after he test rode the bike with the new map.
 
Normally a picture tells a 1000 words, but in this case I think we need more research and to hear from the donor.

Or another picture.
 
I was with Don and Rob from Guhl Motors yesterday.  Fred H. has asked me to share my thoughts with all of you.

First, on Guhl Motors.  I'm glad that Don described their location, otherwise I think I would have had a tough time finding them.  Non-descript metal building behind an outdoor equipment retailer.  I arrived a couple minutes before our agreed to time of 9AM and met Rob and Don.  They gave me a run down on the business and Don explained what his intended approach was for the day.  I immediately felt comfortable with them and their systematic approach to baselining performance and incrementally changing parameters. 

We got the bike strapped onto the dyno and in short order they made the first of six of the pulls for the day.  Don was very patient in allowing me to look over their shoulder and ask questions and take notes.  The first pull was for top speed, with a HP of 131.3 and torque of 89.4 in fifth gear.  I do know that Don seemed really excited to absolutely determine the factory 155MPH speed limiter.

Between the first and second pull, he reflashed the ECU to remove the speed limiter and he shifted the opening of the secondaries by four cells (to the left).  Fuel was left as is.  The second pull showed a top speed of 193MPH.  HP went to 132.5, and torque increased to 91.70.  NOTE:  NO changes to the amount of fuel were made.  The only thing that changed (aside from removing the speed limiter) between the first and second pull was a shift in the point at which the secondaries open.  The amount they opened stayed exactly the same. 

Don felt that he wanted to try going richer on the fuel expecting an overall performance increase. He felt that although the ratio on the sensor looked OK, he could squeeze a bit more performance out of it.  He applied a 5% across the board increase and made another pull.  Torque DROPPED to 91.24 and it seems like I didn't record HP but it was lower.  It was around this time that Don called Fred H. and they talked for the first time, but not the last time of the day. 

Seeing the the decrease in performance, he went 10% lean (from the initial adjustment, or 5% lean from stock) and both HP and torque went back up, 133.77 and 91.91 respectively.  He was pleased with that but still did not like the performance above 8K RPM.  The charts clearly showed it was WAY rich.  He changed fuel settings at 9K to -11%, at 9500 to -16% and at 10K to -20%.  He also changed a setting at between 3 and 4K of 2 or 3% and did two additional pulls.  Both of these pulls were 5% lean from stock, except for the 9K and above range and the 3-4 K range as just described.  First pull results indicate 133.60 and 91.91.  Second pull was 133.52 and 90.61 which is what I believe is reflected in the screen shots he provided, which I've attached.  Across the board, the torque is higher with these settings, and there is no weird stuff going on above the 8K RPM range.

He asked me to take it for a spin and let him know how it felt by seat of the pants.  Not being familiar with the local roads or the local police, I was a bit limited in what I felt comfortable trying.  However, my initial thought was that this bike has NEVER pulled as hard as it was then.  I tried roll-ons in every gear and it just PULLED, hard.  I always considered the bike fast, but this is different.  The changes Don made greatly improved roll on power.  I wasn't really aware that it was lacking in that area, but once you have the mod done, the difference is pretty clear.  I think this is going to be very helpful especially when riding two up.

It's a 100 mile ride back home from his place, with the vast majority of it on 2 lane highways, and a couple miles on interstate.  I played with 4th, 5th, and 6th gear roll-ons and there is no question about the changes being a big improvement.  This isn't a quantum leap in performance, but it is very noticeable.

I asked Don where he feels he is in terms of marketing this re-map.  He is certain that this is THE map for installation on a stock bike.  If you DO NOT have aftermarket exhaust or air filters, or have removed the secondaries, this is the one you would get.  I told him that I would be posting this information and that he should probably be prepared to start getting some calls.  Right now, the only way to get this mod is to send in the ECU or take the bike to them.  He is working on a plug and play remap interface, but I am not sure how long it would be before that is available. 

I've offered my bike to Don in the future if he wants to try anything more.  Don also offered up that if I do mod anything else (air filter, exhaust, etc.,) he'd run the bike again in order to develop maps for them.

I had hoped to get some two-up riding in the next couple of days to make an assessment but it looks like the weather isn't going to cooperate.  As soon as I do, I will post an update.

Time for some new tires.  1100 mostly high speed highway miles in the past week plus those dyno pulls yesterday pretty well toasted the rear! It's got 4300 on it now.  I've ordered a set of the PR3's and they will be installed on Thursday.  Absolutely need them before heading to Maryland next Saturday to take the ARC Level 2 class. 

I hope I've adequately explained things! 
 
I just talked to Gary Murphy at Murphs Kits, and he is going to work out a deal for you on a rear tire. Give him a call or shoot him an email.
 
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