I installed the IGR from Reduction Boss. I have read everything I could find from you guys on correcting the shift concerns from using the speedo healers and Talon ECU and Power Vision. Thanks for taking the time to post what you all have done. It has helped me a bunch. For this reason I thought I would take the time and share what I have done. It was recommended by Jeremy, to not use the speedo healers but if I did, I should set it to 23%. The general consensus I believe is everyone has had a result of soft shift feeling which is obviously undesirable in all cases. I didn't recall ever seeing what setting you all programmed your percentages to. So I have been scratching my head about why recalibrating it at approximately 25% doesn't work with switching just 1 set of gears. So I began by thinking about tire size which everyone that is running an IGR has increased their tire size to my knowledge. I am running 30" tusk terrabites. So I was thinking that this played into this equation somehow. I measured circumference of a set of 27s and my 30s. I was thinking that maybe what I needed to do was calculate the difference the tires might have on the differentials (effective gear ratio) and I read an article from hotrod.com How Gear Works- Car Craft Magazine that talked specifically about this subject. My favorite part was how it talked about this being an ineffective concept. I kept reading because it intrigued me. An example was given about a 4.10 gear set that when the driveshaft was rotated 4.1 revolutions the tire rotates 1 revolution no matter what size of tire you bolt on. Well yes I think we all understand that right? But then it came to me that it was affecting, on a fundamental level, engine rpms only, which is obvious but it was not in any of my immediate ideas of how to solve this issue. However, shifting is based on speed and rpms in our case right? So now what. I have 3 12oclock labs calibrators because in the end I wanted the shifting issue resolved if possible and my speedometer corrected.
So let me backtrack just a little here. Before any math was used or much thinking beforehand I installed the calibrators and figured that if 23% was not correct, I wasn't even going to try that. I thought I would maybe try getting the speedometer corrected and maybe that number is where I would start. I downloaded a gps speed app and I plugged that info into 12oclocks calculator and it said 4.2%. So I programmed it to 4.2 positive and the speedometer was closer but it was actually slightly too far the other way now. I programmed the other 2 calibrators the same just to see what would happen. I was moving in the right direction but I was still hitting the rev limiter before it shifted but I noticed a difference that I could throttle into it more. The goal being full throttle auto upshifts without hitting rev limiter. Shift firmness was considerably more than stock at this point also. So I didnt know what the reduction gear tooth count was, so I made a call out to reduction boss for those numbers. I wanted to put those numbers into 12oclocks calculator to be more accurate because that one has tire circumference also. So plugging in those numbers it gave me a negative -7.2%. I thought that I was headed in the right direction with positive numbers but thought why not try what it says. It was the results I expected as it went the wrong way. At this point I just started guessing with small increments and test driving. I got up to 12.0 positive and it was barely hitting the rev limiter but was shifting on it's own still. The shift firmness was still better than stock. I knew I was really close but thought I would need to adjust it up to approximately 13.0 positive to get all of the rev limit out. So the real question to me is this... why is it 13% and not 23% like Jeremy said it should be or any other number for that fact. My OCD kicked in and this is what I came up with...
Stock info:
Tires: 27
Primary gears: 1.883
1st gear: 2.764
Subtrans: 1.88 (in High)
Rear diff: 3.375
Multiply all those gear ratios together gives you 33.02 as a final drive ratio.
If you plug this ratio in with 27" tire size with a speed of 10mph into a calculator to solve for RPM you get 4109.16
I used the following calculator
IGR info:
Primary: 2.37
1st gear: 2.764
Subtrans: 1.88 (in High)
Rear diff: 3.375
Multiply all the gear ratios gives you 41.56 for a final ratio.
If you plug this ratio in with the 30in. tire size with a speed of 10mph into a calculator to solve for RPM you get 4654.72.
As a side note here: the mph I put in should be irrelevant because the percentage difference should still be the same at any given speed. At least in my mind it should stay the same right?
So I plugged these RPM numbers into a percentage difference calculator and 4655 is a 13.29% increase over 4109.
This is the calculator I used
www.calculator.net
That is why I believe I ended up with an approximate 13% before my shifts where working in auto under full throttle but without the negative soft shift feel that was the result of setting it to the gear reduction percentage itself of 23%. I believe I accomplished what I was after in getting a full throttle, firm upshift in auto mode without hitting the rev limiter. I just need to play with the rear speed sensor to get the speedometer a little closer yet.
Also a side note about low range. I have never really paid attention to what all the different gear ratios where except glancing at the low range ratio of the subtrans is 2.666. So comparing it to a typical 2.7 transfer case out of my 4x4 truck, it seems that there is a big difference when putting it into low range as to what it feels like in our pioneers. On the truck, you are going from a 1:1 high range to 2.7 in my case anyways. But with the pioneer high in the subtrans is 1.88 to 2.666 in low. No wonder it doesn't feel like low is enough in these machines. I was always assuming it was going from 1:1 to the 2.666. Just food for thought.
So what are your thoughts on all of this?
So let me backtrack just a little here. Before any math was used or much thinking beforehand I installed the calibrators and figured that if 23% was not correct, I wasn't even going to try that. I thought I would maybe try getting the speedometer corrected and maybe that number is where I would start. I downloaded a gps speed app and I plugged that info into 12oclocks calculator and it said 4.2%. So I programmed it to 4.2 positive and the speedometer was closer but it was actually slightly too far the other way now. I programmed the other 2 calibrators the same just to see what would happen. I was moving in the right direction but I was still hitting the rev limiter before it shifted but I noticed a difference that I could throttle into it more. The goal being full throttle auto upshifts without hitting rev limiter. Shift firmness was considerably more than stock at this point also. So I didnt know what the reduction gear tooth count was, so I made a call out to reduction boss for those numbers. I wanted to put those numbers into 12oclocks calculator to be more accurate because that one has tire circumference also. So plugging in those numbers it gave me a negative -7.2%. I thought that I was headed in the right direction with positive numbers but thought why not try what it says. It was the results I expected as it went the wrong way. At this point I just started guessing with small increments and test driving. I got up to 12.0 positive and it was barely hitting the rev limiter but was shifting on it's own still. The shift firmness was still better than stock. I knew I was really close but thought I would need to adjust it up to approximately 13.0 positive to get all of the rev limit out. So the real question to me is this... why is it 13% and not 23% like Jeremy said it should be or any other number for that fact. My OCD kicked in and this is what I came up with...
Stock info:
Tires: 27
Primary gears: 1.883
1st gear: 2.764
Subtrans: 1.88 (in High)
Rear diff: 3.375
Multiply all those gear ratios together gives you 33.02 as a final drive ratio.
If you plug this ratio in with 27" tire size with a speed of 10mph into a calculator to solve for RPM you get 4109.16
I used the following calculator
Calculate RPM for Given Speed(MPH), Rear Gear Ratio, and Trans Gear Ratio
Calculate RPM for Given Speed(MPH), Rear Gear Ratio, and Trans Gear Ratio
purperformance.com
IGR info:
Primary: 2.37
1st gear: 2.764
Subtrans: 1.88 (in High)
Rear diff: 3.375
Multiply all the gear ratios gives you 41.56 for a final ratio.
If you plug this ratio in with the 30in. tire size with a speed of 10mph into a calculator to solve for RPM you get 4654.72.
As a side note here: the mph I put in should be irrelevant because the percentage difference should still be the same at any given speed. At least in my mind it should stay the same right?
So I plugged these RPM numbers into a percentage difference calculator and 4655 is a 13.29% increase over 4109.
This is the calculator I used
Percentage Calculator
This free percentage calculator computes a number of values involving percentages, including the percentage difference between two given values.
www.calculator.net
That is why I believe I ended up with an approximate 13% before my shifts where working in auto under full throttle but without the negative soft shift feel that was the result of setting it to the gear reduction percentage itself of 23%. I believe I accomplished what I was after in getting a full throttle, firm upshift in auto mode without hitting the rev limiter. I just need to play with the rear speed sensor to get the speedometer a little closer yet.
Also a side note about low range. I have never really paid attention to what all the different gear ratios where except glancing at the low range ratio of the subtrans is 2.666. So comparing it to a typical 2.7 transfer case out of my 4x4 truck, it seems that there is a big difference when putting it into low range as to what it feels like in our pioneers. On the truck, you are going from a 1:1 high range to 2.7 in my case anyways. But with the pioneer high in the subtrans is 1.88 to 2.666 in low. No wonder it doesn't feel like low is enough in these machines. I was always assuming it was going from 1:1 to the 2.666. Just food for thought.
So what are your thoughts on all of this?
