Shift into 6th gear at 33 MPH?
05-14-2010, 12:46 PM
#63
Not another one who thinks the car's computer has the ability to prevent lugging the engine in a 6MT car.LOL, I'm really surprised that anyone who considers himself an enthusiast (and especially a 6MT driver) wouldn't understand that it doesn't work like that. Trust me, anyone with a 6MT can easily lug the engine any time he chooses.
05-14-2010, 12:49 PM
#64
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Not another one who thinks the car's computer has the ability to prevent lugging the engine in a 6MT car.LOL, I'm really surprised that anyone who considers himself an enthusiast (and especially a 6MT driver) wouldn't understand that it doesn't work like that. Trust me, anyone with a 6MT can easily lug the engine any time he chooses.
05-14-2010, 12:51 PM
#65
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Car cruises fine in 6th gear at ~33mph. Just don't try to accelerate quickly.
However, based on it's performance in other gears, I wasn't able to see much of an efficiency boost in 6th gear over 4th or 5th gears.
However, based on it's performance in other gears, I wasn't able to see much of an efficiency boost in 6th gear over 4th or 5th gears.
05-14-2010, 01:06 PM
#66
But honestly, I don't see the point in continuing this debate. We'll just have to let people learn for themselves. It's still an interesting topic to me....and you certainly won't see me cruising around on back roads doing 30 MPH in 6th gear. 4th gear will work just fine for me!
05-14-2010, 03:49 PM
#67
Put the car in 6th at 30 MPH and floor it. It will boooooooog just like a tractor trailer. That's not exhaust drone. That's lugging. And it's VERY bad for the engine, specifically the bearings.
Not sure why this is even up for discussion. So here are the facts:
1. Lugging the engine is bad for cars with aggressive cams such as ours.
2. Lugging the engine is bad for the engine, specifically the bearings and will reduce engine life.
3. Attempting to accelerate in 6th gear at 33 MPH will cause lugging. Again, this is bad for the engine over time.
If anyone disagrees with any of these, I'd like to know why. Just curious how someone can argue something that has been proven by engineers. Why do you think AT vehicles stay in a lower gear at lower speeds? Cars, especially modern cars with modern engines, aren't designed to handle high load at low speeds.
Not sure why this is even up for discussion. So here are the facts:
1. Lugging the engine is bad for cars with aggressive cams such as ours.
2. Lugging the engine is bad for the engine, specifically the bearings and will reduce engine life.
3. Attempting to accelerate in 6th gear at 33 MPH will cause lugging. Again, this is bad for the engine over time.
If anyone disagrees with any of these, I'd like to know why. Just curious how someone can argue something that has been proven by engineers. Why do you think AT vehicles stay in a lower gear at lower speeds? Cars, especially modern cars with modern engines, aren't designed to handle high load at low speeds.
Learn your own car. You own a V6 with two camshafts. Don't tell me it's a SOHC like an Acura TL now
LOL, of course torque multiplication has bearing on lugging an engine. That's why we have transmissions with gears. You have got to be kidding me, right? Is today April 1st?
You really need to understand the relationship between throttle angles, RPM, and torque multiplication. In a nutshell, that's really what we're talking about here. When you have a combination of low torque multiplication (high gear), low RPM, and large throttle openings, this can easily result in lugging the engine.
Now lets remove one of those variables....say we now have high torque multiplication (low gear), but still have low RPM and a large throttle opening. Hmmm....no problem. The engine will not lug. This isn't magic, it's pretty basic stuff.
Of if you want, we can change the variables again. Lets say we have low torque multiplication (high gear), high RPM, and a large throttle opening angle. Again, no problem....the engine is happy.
The point that you seem to be missing over and over again is that the AT will not allow the first scenario. It sill simply shift to avoid lugging the engine. This is the basic premise of an AT. Now the MT on the other hand is 100% controlled by the driver, so there's no ECU involvement whatsoever.
BTW, I know a few things about VVEL. It's great technology and much more advanced than BMW's VANOS. In fact, I fully expect to see 100% variable valvetrains that are electrically actuated and will completely replace the throttle plates (there wouldn't be a need for them at all) while allowing for more power and fuel economy than we experience today. It's all awesome technology, but the only thing holding it back now is the limitations of our 12-volt electrical systems. And that's also why I think we'll see 18-volt systems on cars in the near future.
You really need to understand the relationship between throttle angles, RPM, and torque multiplication. In a nutshell, that's really what we're talking about here. When you have a combination of low torque multiplication (high gear), low RPM, and large throttle openings, this can easily result in lugging the engine.
Now lets remove one of those variables....say we now have high torque multiplication (low gear), but still have low RPM and a large throttle opening. Hmmm....no problem. The engine will not lug. This isn't magic, it's pretty basic stuff.
Of if you want, we can change the variables again. Lets say we have low torque multiplication (high gear), high RPM, and a large throttle opening angle. Again, no problem....the engine is happy.
The point that you seem to be missing over and over again is that the AT will not allow the first scenario. It sill simply shift to avoid lugging the engine. This is the basic premise of an AT. Now the MT on the other hand is 100% controlled by the driver, so there's no ECU involvement whatsoever.
BTW, I know a few things about VVEL. It's great technology and much more advanced than BMW's VANOS. In fact, I fully expect to see 100% variable valvetrains that are electrically actuated and will completely replace the throttle plates (there wouldn't be a need for them at all) while allowing for more power and fuel economy than we experience today. It's all awesome technology, but the only thing holding it back now is the limitations of our 12-volt electrical systems. And that's also why I think we'll see 18-volt systems on cars in the near future.
And no, the driver is not 100% in control. Unless you converted your car to a traditional throttle cable. Oh, wait, that would be.... insanely stupid on this car.
Not another one who thinks the car's computer has the ability to prevent lugging the engine in a 6MT car.LOL, I'm really surprised that anyone who considers himself an enthusiast (and especially a 6MT driver) wouldn't understand that it doesn't work like that. Trust me, anyone with a 6MT can easily lug the engine any time he chooses.
This isn't a car from the 80's with a throttle cable. You are not in 100% control, even with a MT. The gas pedal is just a giant potentiometer modifying a signal going to the ECU, which interprets it as how much output you want from the engine. The ECU ultimately decides how much output there is, not the driver. In fact, if you look at the throttle map, the position of the gas pedal and the opening % of the throttle bodies have NO CORRELATION WHATSOEVER.
Originally Posted by since you're an engineer and you like technical descriptions
The accelerator pedal position sensor is installed on the upper end of the accelerator pedal assembly. The sensor detects the accelerator position and sends a signal to the ECM.
Accelerator pedal position sensor has two sensors. These sensors are a kind of potentiometers which transform the accelerator pedal position into output voltage, and emit the voltage signal to the ECM. In addition, these sensors detect the opening and closing speed of the accelerator pedal and feed the voltage signals to the ECM. The ECM judges the current opening angle of the accelerator pedal from these signals and controls the throttle control motor based on these signals.
Idle position of the accelerator pedal is determined by the ECM receiving the signal from the accelerator pedal position sensor. The ECM uses this signal for the engine operation such as fuel cut.
Accelerator pedal position sensor has two sensors. These sensors are a kind of potentiometers which transform the accelerator pedal position into output voltage, and emit the voltage signal to the ECM. In addition, these sensors detect the opening and closing speed of the accelerator pedal and feed the voltage signals to the ECM. The ECM judges the current opening angle of the accelerator pedal from these signals and controls the throttle control motor based on these signals.
Idle position of the accelerator pedal is determined by the ECM receiving the signal from the accelerator pedal position sensor. The ECM uses this signal for the engine operation such as fuel cut.
Last edited by Mike; 05-14-2010 at 03:55 PM.
05-14-2010, 04:10 PM
#68
The AT is shifting so fast you're not seeing it. Going back to the previous post, when the RPMs jump when you're at 30 mph, do you think that's RPM play from the torque converter? If so, you're badly mistaken. This car locks the torque converter if you're in 3rd gear or higher (7AT) to reduce drivetrain loss.
Your response alone shows the holes in your knowledge of VVEL. The throttle bodies, under normal operation, remain open. VVEL controls intake volume, not the throttle bodies.
And no, the driver is not 100% in control. Unless you converted your car to a traditional throttle cable. Oh, wait, that would be.... insanely stupid on this car.
If your nutty theory was correct, then the engine would not allow RPM to rise in the event of excessive load.
What's funny about you is that you claim to deal in facts, yet you have no answer when I ask you how your supposed facts can be correct when I can easily lug the engine of a 6MT car. Instead of continually spewing out BS, explain to me two things:
1- why is it that anyone with a 6MT can lug the engine (this is a fact, not opinion)
2- why is it that the ECU doesn't stop RPM from climbing when the engine is experiencing excess load because of lugging?
You simply don't get it. Intake volume and power output are 100% computer controlled. You can step on the gas pedal more, but the ECU won't allow for more engine output if it thinks it will damage the engine.
This isn't a car from the 80's with a throttle cable. You are not in 100% control, even with a MT. The gas pedal is just a giant potentiometer modifying a signal going to the ECU, which interprets it as how much output you want from the engine. The ECU ultimately decides how much output there is, not the driver. In fact, if you look at the throttle map, the position of the gas pedal and the opening % of the throttle bodies have NO CORRELATION WHATSOEVER.
Whew, it's hard work schooling you.... LOL
05-14-2010, 04:37 PM
#69
MSCA.
Your impressions of this car are from a few test drives. Mine is from hundreds of hours of seat time in stop and go traffic, open highways, back roads, and in high performance driving conditions.
Where did I ever dispute that a mechanical overrev is not user error?
Do you understand what a lock-up TC is? Do you understand the difference between when a TC is multiplying the torque output from the engine and when it is purely a mechanical coupling?
I'll state again, hoping it goes into your head. Under normal operation, the throttle bodies remain open, and the intake valves (VVEL controlled), determine intake charge volume.
http://www.nissan-global.com/EN/DOCU...0713VVEL-e.pdf
Refer to section 2.1.2 and 2.2.1
There is nothing magical about pulling timing and reducing intake charge to reduce output.
In fact, that's part of the reason why people complain about the lack of low end power. Engine output is lowered at the low end. Do you REALLY think a modern 3.7L v6 could only make 150 ft/lbs at 1500 RPM? Hell, even the old VQ35DE made 175 at 1500 RPM.
1. you can always create extenuating circumstances.
1a. I don't think you're correctly differentiating the "boooooooog sound like a tractor from the exhaust" from the "sounds like a diesel truck" sound of lugging.
2. see above.
http://www.nissan-global.com/EN/DOCU...0713VVEL-e.pdf
Fact: you are wrong. No correlation between throttle position and throttle body position.
The throttle body is there for emissions reasons.
Since you felt it necessary for you to state your qualifications, I suppose I should mention that I worked for Infiniti at the time this car was being developed, and was directly involved in some of the testing phases.
Your impressions of this car are from a few test drives. Mine is from hundreds of hours of seat time in stop and go traffic, open highways, back roads, and in high performance driving conditions.
Forcing a mechanical over-rev is NOTHING like attempting to reprogram shifting behavior. The fact that you are even trying to make any correlation proves your ignorance to me. BTW, "forcing" (your word, not mine) a mechanical over-rev is as easy as accidently choosing the wrong gear while downshifting under deceleration. The rev limiter will not protect the engine under a mechanical over-rev
http://www.nissan-global.com/EN/DOCU...0713VVEL-e.pdf
Refer to section 2.1.2 and 2.2.1
Electronic throttles are nothing new...they've been around for years now. Whether a throttle has a cable or not is irrelevant. The fact of the matter is that the transmission is 100% controlled by a 6MT driver, and that's the whole point here. No wonder you're having such a hard time understand this...You seem to think that the car's computer has some magical ability to prevent lugging the engine, when all along it's the transmission's duty to do that...and it does it well on an AT car, but on an MT car it is 100% controlled by the driver.
What's funny about you is that you claim to deal in facts, yet you have no answer when I ask you how your supposed facts can be correct when I can easily lug the engine of a 6MT car. Instead of continually spewing out BS, explain to me two things:
1- why is it that anyone with a 6MT can lug the engine (this is a fact, not opinion)
2- why is it that the ECU doesn't stop RPM from climbing when the engine is experiencing excess load because of lugging?
1- why is it that anyone with a 6MT can lug the engine (this is a fact, not opinion)
2- why is it that the ECU doesn't stop RPM from climbing when the engine is experiencing excess load because of lugging?
1a. I don't think you're correctly differentiating the "boooooooog sound like a tractor from the exhaust" from the "sounds like a diesel truck" sound of lugging.
2. see above.
Negative. Not even close. That is a ridiculous statement.
You're somehow fixated on the whole throttle cable thing. LOL, a cable actuated throttle serves the same exact purpose as your electronic throttle (a potentiometer is nothing but a variable resistor) and behaves in the same way. The more you step on the gas, the wider the throttle plates open. The ONLY thing that is different on the G engine is the VVEL system, which does respond to several input variables to determine what the driver wants from the engine. But again, that has nothing to do with lugging the engine and the ECU has no outputs whatsoever to prevent that. This is a fact that can easily be proven by anyone who hops in his 6MT G37 and proceeds to lug the engine.
Whew, it's hard work schooling you.... LOL
You're somehow fixated on the whole throttle cable thing. LOL, a cable actuated throttle serves the same exact purpose as your electronic throttle (a potentiometer is nothing but a variable resistor) and behaves in the same way. The more you step on the gas, the wider the throttle plates open. The ONLY thing that is different on the G engine is the VVEL system, which does respond to several input variables to determine what the driver wants from the engine. But again, that has nothing to do with lugging the engine and the ECU has no outputs whatsoever to prevent that. This is a fact that can easily be proven by anyone who hops in his 6MT G37 and proceeds to lug the engine.
Whew, it's hard work schooling you.... LOL
Fact: you are wrong. No correlation between throttle position and throttle body position.
The throttle body is there for emissions reasons.
Since you felt it necessary for you to state your qualifications, I suppose I should mention that I worked for Infiniti at the time this car was being developed, and was directly involved in some of the testing phases.
05-14-2010, 05:19 PM
#70
Hahahahaha...too much info to keep doing this repetitive quotes. So I'll wrap up by saying this:
1- you are digging yourself into a deeper and deeper hole. If you read the info in the pdf you provided, you'll see that throttle angle does in fact play a part in controlling intake volume. You can't argue that because it is printed in the pdf you supplied. And that's exactly what I said all along-- VVEL technology works WITH throttle opening. Again...it is very possible to lug the engine. You explicitly stated that the ECU would not allow the engine to damage itself. FALSE
2- I don't care if you were President and CEO of Nissan in Japan when this engine was being developed. It is clear to anyone with any common sense that you don't have any idea what you're talking about. Your own literature goes against your theories & explanations.
Sorry, but I'm beyond bored now, so I'll let you go ahead and get the last word. Say whatever you want and believe that you are correct. The rest of us know better. LOL
1- you are digging yourself into a deeper and deeper hole. If you read the info in the pdf you provided, you'll see that throttle angle does in fact play a part in controlling intake volume. You can't argue that because it is printed in the pdf you supplied. And that's exactly what I said all along-- VVEL technology works WITH throttle opening. Again...it is very possible to lug the engine. You explicitly stated that the ECU would not allow the engine to damage itself. FALSE
2- I don't care if you were President and CEO of Nissan in Japan when this engine was being developed. It is clear to anyone with any common sense that you don't have any idea what you're talking about. Your own literature goes against your theories & explanations.
Sorry, but I'm beyond bored now, so I'll let you go ahead and get the last word. Say whatever you want and believe that you are correct. The rest of us know better. LOL
05-14-2010, 05:31 PM
#71
2.1.2 VVEL controls intake amount through intake-valves of the combustion chamber, where conventional engines used throttle valves
2.2.3 VVEL-equipped engines control air amount at intake valve by the c ombustion chamber entrance, which enabels necessary air to be sent promptly to combustion chamber
2.2.8 VVEL is a system which controls the amount of air intake directly at the intake-valve right before the combustion chamber
05-14-2010, 08:39 PM
#72
what is the point of all this?
One guy says the engine will lug only under idle RPM....another guy says you can lug it at RPMs above idle?...
How does the ECU PREVENT the engine from lugging above idle RPMs? Does lugging stop the moment RPMs go, say, 100 RPMs above idle?
If the ECU prevented the engine from lugging below idle then no one would stall?
Has anyone ever accelerated from a stop in 2nd or 3rd gears? When you start in 1st gear you're right at idle RPMs when you do...so any higher gear would be BELOW that when you start.....
I'm confused. but all i know is that when i mash it in 6th gear around 30mph i feel/hear something that doesnt feel/sound right!
One guy says the engine will lug only under idle RPM....another guy says you can lug it at RPMs above idle?...
How does the ECU PREVENT the engine from lugging above idle RPMs? Does lugging stop the moment RPMs go, say, 100 RPMs above idle?
If the ECU prevented the engine from lugging below idle then no one would stall?
Has anyone ever accelerated from a stop in 2nd or 3rd gears? When you start in 1st gear you're right at idle RPMs when you do...so any higher gear would be BELOW that when you start.....
I'm confused. but all i know is that when i mash it in 6th gear around 30mph i feel/hear something that doesnt feel/sound right!
05-14-2010, 11:42 PM
#73
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The AT is shifting so fast you're not seeing it. Going back to the previous post, when the RPMs jump when you're at 30 mph, do you think that's RPM play from the torque converter? If so, you're badly mistaken. This car locks the torque converter if you're in 3rd gear or higher (7AT) to reduce drivetrain loss.
Learn your own car. You own a V6 with two camshafts. Don't tell me it's a SOHC like an Acura TL now
Learn your own car. You own a V6 with two camshafts. Don't tell me it's a SOHC like an Acura TL now
What are you talking about? "AT is shifting so fast...blah blah, Lurn ur car, blah blah." You're attempting to sling insults because you can support any of your rediculous claims. Period.
Again, you can't dispute these facts
1. Lugging the engine is bad for cars with aggressive cams such as ours.
2. Lugging the engine is bad for the engine, specifically the bearings and will reduce engine life.
3. Attempting to accelerate in 6th gear at 33 MPH will cause lugging. Again, this is bad for the engine over time.
None of the above has anything to do with VVEL, shifting patterns, "lurning ur engine", it's basic car knowledge, not rocket surgery or brain science.
05-14-2010, 11:58 PM
#74
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Could not have stated it any better!
