V6 Tune Questions
4/12/14, 05:46 PM
#21
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There are like 5.7 quadrillion threads on this. 
4/12/14, 05:58 PM
#23
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just put it in park, rev it up and watch how slow the decel is. its more noticable in the manual though since if youre gunning it then let out of it and coast with the clutch in it take for ever for the rpms to come back down. i think the main problem is the massive intake manifold on these v6's but that helps with power. id rather have more power than slow decel.
4/12/14, 06:06 PM
#24
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just put it in park, rev it up and watch how slow the decel is. its more noticable in the manual though since if youre gunning it then let out of it and coast with the clutch in it take for ever for the rpms to come back down. i think the main problem is the massive intake manifold on these v6's but that helps with power. id rather have more power than slow decel.
The slow decel is related to EPA conformance. So the engine burns raw fuel more completely - rather than an immediate throttle cut off which would expel unburned gases into the atmosphere. Auto manufacturers have done this since the 80's - even on carb engines.
4/12/14, 08:00 PM
#25
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because the larger the manifold size the longer it takes to get it up to the 18-20 inches of vacuum after the throttle is closed. basicly theres more air in the manifold for it to use. sorry if that doesnt make since i suck at explaining.
yeah its called dashpot. although the intake manifold still plays a part in it since it can only decel so quickly even if the throttle plate is closed immediately.
yeah its called dashpot. although the intake manifold still plays a part in it since it can only decel so quickly even if the throttle plate is closed immediately.
4/12/14, 08:07 PM
#26
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Either way, it's extraordinarily excessive with this car. I wonder if the manual cars are tuned different then auto from the factory...I don't see how it would even work with an auto unless it shifts dreadfully slow.
4/12/14, 08:16 PM
#27
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auto's shift completely different. the throttle doesnt close during a shift in a auto. the bands or clutch packs in the trans slip for a split second forcing the engine to slow down to the proper speed. although some of the new transmissions kill fuel to the engine during a shift to make the trans last longer since it wouldnt be slipping as much during a shift. but i dont believe the trans in the mustang works like that.
Last edited by southcarolina12; 4/12/14 at 08:18 PM.
4/13/14, 08:21 AM
#28
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so whats the solution? I don't want slow/delayed deceleration but I want the power and throttle response. Can I have both with a custom tune? It sounds like people are having issues with this.
4/15/14, 12:12 PM
#30
Cobra Member
So let's say I want to install a tune to get rid of throttle response delay and would like to do something about the limiter, but I'm not ready to spring for a new drive shaft at this point. I assume I could have the tune setup to raise the limiter to say 120 or 125 MPH for now to give me slightly longer legs without too much risk. True or not?
4/15/14, 01:14 PM
#31
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So let's say I want to install a tune to get rid of throttle response delay and would like to do something about the limiter, but I'm not ready to spring for a new drive shaft at this point. I assume I could have the tune setup to raise the limiter to say 120 or 125 MPH for now to give me slightly longer legs without too much risk. True or not?
4/15/14, 04:35 PM
#32
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So let's say I want to install a tune to get rid of throttle response delay and would like to do something about the limiter, but I'm not ready to spring for a new drive shaft at this point. I assume I could have the tune setup to raise the limiter to say 120 or 125 MPH for now to give me slightly longer legs without too much risk. True or not?
4/15/14, 05:19 PM
#34
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4/15/14, 06:52 PM
#35
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The significance of the different rear end ratios just dawned on me and a quick calculation showed that my drive shaft would be turning about 860 fewer RPMs at 120 than yours with a 3.31 rear end. So mine would be turning about 82% of the speed of yours. That, of course, changes with tire size, but the principal holds true.
4/15/14, 07:33 PM
#37
Cobra Member
I wasn't paying enough attention to notice that yours is an M6. Mine is an automatic and fifth is .86. I don't have a 1.00 gear. Unless your 6th is also .69, my numbers are off even further than what the different tires would cause.
4/15/14, 07:39 PM
#38
Cobra R Member
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I believe sixth gear is VERY close between the two.
4/15/14, 08:24 PM
#39
Cobra Member
So now I'm trying to understand the functioning of the drive by wire system and am harking back to my programming days. I assume that when I press the accelerator all the way to the floor there is a WOT signal sent to the computer. The computer then sends a signal to the throttle body to open, but it must not be to open too wide. The car begins to move and you can hear the engine start to rev, but it is obviously not at full throttle. There must then be a timing delay programmed into the computer (I can only assume it has to do with either emissions or fuel economy, or possibly something to do with valve timing). Following this delay the computer sends the instruction to the throttle body to open all the way. Now we get some serious sound and motion. I then assume that a tune that eliminates the throttle response delay must (putting things very simply) eliminate the initial signal to partially open the throttle body and the timing delay and have the immediate response to the accelerator signal be a signal for WOT. Does this make sense?
4/16/14, 07:05 PM
#40
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So now I'm trying to understand the functioning of the drive by wire system and am harking back to my programming days. I assume that when I press the accelerator all the way to the floor there is a WOT signal sent to the computer. The computer then sends a signal to the throttle body to open, but it must not be to open too wide. The car begins to move and you can hear the engine start to rev, but it is obviously not at full throttle. There must then be a timing delay programmed into the computer (I can only assume it has to do with either emissions or fuel economy, or possibly something to do with valve timing). Following this delay the computer sends the instruction to the throttle body to open all the way. Now we get some serious sound and motion. I then assume that a tune that eliminates the throttle response delay must (putting things very simply) eliminate the initial signal to partially open the throttle body and the timing delay and have the immediate response to the accelerator signal be a signal for WOT. Does this make sense?