No Device: Possibly the most basic tuning question
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Road Warrior
Joined: Jun 2015
Posts: 1,325
Likes: 140
From: Edinburgh UK
Possibly the most basic tuning question
OK, this may show me to be the least pro or DIY guy in here (blush) but...
You have changed some bits (but CI stays the same) and re-tuned your EFI...
Does the reduction/increase in VE between new and stock maps equate to a reduction/increase in torque(power) of the tuned engine?
And ...would you expect the difference between the two cylinders to be kind of similar?
You have changed some bits (but CI stays the same) and re-tuned your EFI...
Does the reduction/increase in VE between new and stock maps equate to a reduction/increase in torque(power) of the tuned engine?
And ...would you expect the difference between the two cylinders to be kind of similar?
Last edited by Gordon61; Jan 29, 2017 at 06:19 AM.
Cruiser
Joined: Feb 2010
Posts: 166
Likes: 34
From: Prospect, CT
Hey Buddy,
Welcome to the forums, don't mind those guys - whether we want to admit it or not, we've all been where you are, trying to understand what we're doing with the vague bits and pieces of information we get from responses.
The VE tables don't define power - they (in effect) tell the ECM how much air is being drawn into the cylinder, and hence, using the AFR (air/fuel ratio) table, how much fuel should be injected to reach the AFR you set for that cell.
Here's how it works: You first set your motor size in the Constants table, let's say that's 103 cu in. The software then knows that each cylinder will fill with 51.5 ci of air if it fills completely. But because we have a throttle that blocks the air intake, and (possibly) a cam/exhaust that can create enough suction to draw more than 100% of the cylinder volume, we use the software to measure the amount of air filling the cylinder at any cell. A VE cell number of 80, say, tells the program that at that cell, the cylinder is drawing 80% of 51.5 ci, or 41,2 ci of air. It now knows how much fuel to inject to arrive at the AFR you asked for in the AFR table.
So (I think) to answer your question, using a VE table from another file isn't going to make the bike more powerful - its just going to make it too rich or too lean at whatever cells aren't accurately entered. Did that help?
Regarding the two cylinders, they can be markedly different, mostly because the exhaust paths are very different. Don't try to mold the rear to match the front - trust the data. Just smooth it once or twice.
Hope that helps!
Welcome to the forums, don't mind those guys - whether we want to admit it or not, we've all been where you are, trying to understand what we're doing with the vague bits and pieces of information we get from responses.
The VE tables don't define power - they (in effect) tell the ECM how much air is being drawn into the cylinder, and hence, using the AFR (air/fuel ratio) table, how much fuel should be injected to reach the AFR you set for that cell.
Here's how it works: You first set your motor size in the Constants table, let's say that's 103 cu in. The software then knows that each cylinder will fill with 51.5 ci of air if it fills completely. But because we have a throttle that blocks the air intake, and (possibly) a cam/exhaust that can create enough suction to draw more than 100% of the cylinder volume, we use the software to measure the amount of air filling the cylinder at any cell. A VE cell number of 80, say, tells the program that at that cell, the cylinder is drawing 80% of 51.5 ci, or 41,2 ci of air. It now knows how much fuel to inject to arrive at the AFR you asked for in the AFR table.
So (I think) to answer your question, using a VE table from another file isn't going to make the bike more powerful - its just going to make it too rich or too lean at whatever cells aren't accurately entered. Did that help?
Regarding the two cylinders, they can be markedly different, mostly because the exhaust paths are very different. Don't try to mold the rear to match the front - trust the data. Just smooth it once or twice.
Hope that helps!
Thread Starter
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Road Warrior
Joined: Jun 2015
Posts: 1,325
Likes: 140
From: Edinburgh UK
It's a simple enough question; I thought it might have made for an interesting one 
How about this then...
Have a look at the VE tables in your stock tune, compare them to the VE tables after tuning ...where do you think you have made (or lost) torque/power?
Lower VE = less air = less fuel (to maintain AFR) = less of torque/power
The torque equation is much more complicated than just fuel and air, but the basic question was ...is there any correlation between change in VE table and change in torque/power
How about this then...
Have a look at the VE tables in your stock tune, compare them to the VE tables after tuning ...where do you think you have made (or lost) torque/power?
Lower VE = less air = less fuel (to maintain AFR) = less of torque/power
The torque equation is much more complicated than just fuel and air, but the basic question was ...is there any correlation between change in VE table and change in torque/power
Last edited by Gordon61; Jan 31, 2017 at 09:05 AM.
Seasoned HDF Member
Joined: Dec 2005
Posts: 19,944
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From: poway
It's a simple enough question; I thought it might have made for an interesting one
How about this then...
Have a look at the VE tables in your stock tune, compare them to the VE tables after tuning ...where do you think you have made (or lost) torque/power?
Lower VE = less air = less fuel (to maintain AFR) = less of torque/power
The torque equation is much more complicated than just fuel and air, but the basic question was ...is there any correlation between change in VE table and change in torque/power
How about this then...
Have a look at the VE tables in your stock tune, compare them to the VE tables after tuning ...where do you think you have made (or lost) torque/power?
Lower VE = less air = less fuel (to maintain AFR) = less of torque/power
The torque equation is much more complicated than just fuel and air, but the basic question was ...is there any correlation between change in VE table and change in torque/power
If the motor is too rich to start, dropping VEs will increase power.. Changing anything that increases the real VE should make more power but still there is a range of AFRs that at which power does not change. So.. If the results of a some tuning sequence says to increase VEs and you do, you might not be getting anything..
Last edited by Max Headflow; Jan 31, 2017 at 10:23 AM. Reason: So.
Thread Starter
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Road Warrior
Joined: Jun 2015
Posts: 1,325
Likes: 140
From: Edinburgh UK
You're right of course ..."Stock" is not a good example for anything much 
although I'd maybe hope there was more increase than decrease across the tables??
But if we consider that we have a decent baseline, then changes to the real VE should be indicative ...at least to some extent.
So comparing two of your own tunes, one with standard the other with quiet baffles for example? ...or trying a different exhaust?
although I'd maybe hope there was more increase than decrease across the tables??But if we consider that we have a decent baseline, then changes to the real VE should be indicative ...at least to some extent.
So comparing two of your own tunes, one with standard the other with quiet baffles for example? ...or trying a different exhaust?
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Cruiser
Joined: Feb 2010
Posts: 166
Likes: 34
From: Prospect, CT
Okay, I think I get what you're saying....
Yeah - if displacement stays the same, and AFRs are correct, and the VE tables are accurate, higher VE number should indicate more power in that area.
That's actually a cool idea. You could copy the VE table from your new tune onto your old table, and then "compare edits to baseline" to get an idea of where you gained and where you lost (if at all). Just don't save it that way.
Yeah - if displacement stays the same, and AFRs are correct, and the VE tables are accurate, higher VE number should indicate more power in that area.
That's actually a cool idea. You could copy the VE table from your new tune onto your old table, and then "compare edits to baseline" to get an idea of where you gained and where you lost (if at all). Just don't save it that way.
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Seasoned HDF Member
Joined: Dec 2005
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From: poway
You're right of course ..."Stock" is not a good example for anything much although I'd maybe hope there was more increase than decrease across the tables??
But if we consider that we have a decent baseline, then changes to the real VE should be indicative ...at least to some extent.
So comparing two of your own tunes, one with standard the other with quiet baffles for example? ...or trying a different exhaust?
although I'd maybe hope there was more increase than decrease across the tables??But if we consider that we have a decent baseline, then changes to the real VE should be indicative ...at least to some extent.
So comparing two of your own tunes, one with standard the other with quiet baffles for example? ...or trying a different exhaust?
On a Tmax you simply download the map from the unit and see what has changed in the learned PWs.
Club Member
Joined: Jul 2014
Posts: 11,471
Likes: 3,572
From: Idaho
Okay, I think I get what you're saying....
Yeah - if displacement stays the same, and AFRs are correct, and the VE tables are accurate, higher VE number should indicate more power in that area.
That's actually a cool idea. You could copy the VE table from your new tune onto your old table, and then "compare edits to baseline" to get an idea of where you gained and where you lost (if at all). Just don't save it that way.
Yeah - if displacement stays the same, and AFRs are correct, and the VE tables are accurate, higher VE number should indicate more power in that area.
That's actually a cool idea. You could copy the VE table from your new tune onto your old table, and then "compare edits to baseline" to get an idea of where you gained and where you lost (if at all). Just don't save it that way.
The bike barely ran, and got 10 mpg.
Obviously that was a stupid move on his part, but this is more complex than most folks realize.