Rev Hang in Manual Transmission

kitkat

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So this didn’t click for me until I saw a post about it on Facebook and my test drive at Lotus Boardwalk in the US had mentioned something about it.

But apparently the Lotus does not close the throttle plate after you let go of the throttle and clutch in for emission requirements?

Is that the case?
Has that been the case for past any past Lotus cars?
Is it possible to remove this?

I thought I was just a little rusty matching revs or unfamiliar with this particular transmission.
 

VL3X

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Pretty typical with fly by wire. Some vehicles are worse than others. The WRX hang was terrible. I didn't notice it when I test drove the Emira.
 
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kitkat

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Pretty typical with fly by wire. Some vehicles are worse than others. The WRX hang was terrible. I didn't notice it when I test drove the Emira.
Guess I haven’t drive a modern manual before :)
 

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Can you describe this more? I’m used to a 2013 very analog Audi and any manual before was less modern. When you go to rev match you are saying the revs stay up longer or drop sharply after clutch in and foot off?
 

VL3X

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Can you describe this more? I’m used to a 2013 very analog Audi and any manual before was less modern. When you go to rev match you are saying the revs stay up longer or drop sharply after clutch in and foot off?

The revs stay high and don't drop as naturally as you'd traditionally expect when the clutch is depressed. This is supposed to help with rev matching for the granny shifters.
 

MikeLima

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I drove a 991 911 for the first time a few weeks ago. The rev hang in that car actually surprised me. Even though the NA engine revs very freely, the rpms take much longer to fall compared to my S2000.

Can anybody make a comparison to either one of those cars?
 
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kitkat

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I drove a 991 911 for the first time a few weeks ago. The rev hang in that car actually surprised me. Even though the NA engine revs very freely, the rpms take much longer to fall compared to my S2000.

Can anybody make a comparison to either one of those cars?
It won’t be at all like the s2k, had one for 13 years, the revs just come down very slowly in comparison since the throttle plate is being held partially open, it’s just particularly noticeable in upshifts.
 

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The revs stay high and don't drop as naturally as you'd traditionally expect when the clutch is depressed. This is supposed to help with rev matching for the granny shifters.
Sorry, just need confirmation. Are you saying that the revs stay high for longer?

Also when downshifting, the revs would be low and then we have to apply throttle before reengaging the engine with the clutch. How does this help if the revs are already to low?

I take it that the Lotus Emira does not have an auto blip function right?
 

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Good this thread popped up again. Rev hang is very noticeable in my Emira (picked up Thurs last week).

I have only done a few trips beyond the drive back to Bucks from Hethel but the rev hang is really noticeable.

I will let things bed in and focus hard on my gear changes. But before anyone asks I drive manuals a lot and have a GR Yaris, GT3 and the kids have a manual Polo.

I don’t get rev hang in any of those.

On my quick trip this morning I focused really hard and basically lifted off the throttle way before engaging the clutch and changing up. A bit better but not natural and didn’t stop it completely.

Still running in so will reserve more judgement until able to use more revs.

Note this is only relevant when going up the box when as you go to the next gear the revs will drop as the clutch bites. When changing down it would be helpful if I wasn’t already rev matching or heel and toeing.
 
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kitkat

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Good this thread popped up again. Rev hang is very noticeable in my Emira (picked up Thurs last week).

I have only done a few trips beyond the drive back to Bucks from Hethel but the rev hang is really noticeable.

I will let things bed in and focus hard on my gear changes. But before anyone asks I drive manuals a lot and have a GR Yaris, GT3 and the kids have a manual Polo.

I don’t get rev hang in any of those.

On my quick trip this morning I focused really hard and basically lifted off the throttle way before engaging the clutch and changing up. A bit better but not natural and didn’t stop it completely.

Still running in so will reserve more judgement until able to use more revs.

Note this is only relevant when going up the box when as you go to the next gear the revs will drop as the clutch bites. When changing down it would be helpful if I wasn’t already rev matching or heel and toeing.
Don’t think this will change as you run the car in, this is a software thing from my limited understanding.

You’re going to have to get used to it I think.
 

Emirahep

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Don’t think this will change as you run the car in, this is a software thing from my limited understanding.

You’re going to have to get used to it I think.
I fear you may be right. It’s not my incompetence or technique so by getting used to it it will be more like grin and bear it ! Will be interesting if others find the same or whether it varies between cars.
 

eclat2emira

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Don’t think this will change as you run the car in, this is a software thing from my limited understanding.

You’re going to have to get used to it I think.
Good this thread popped up again. Rev hang is very noticeable in my Emira (picked up Thurs last week).

I have only done a few trips beyond the drive back to Bucks from Hethel but the rev hang is really noticeable.

I will let things bed in and focus hard on my gear changes. But before anyone asks I drive manuals a lot and have a GR Yaris, GT3 and the kids have a manual Polo.

I don’t get rev hang in any of those.

On my quick trip this morning I focused really hard and basically lifted off the throttle way before engaging the clutch and changing up. A bit better but not natural and didn’t stop it completely.

Still running in so will reserve more judgement until able to use more revs.

Note this is only relevant when going up the box when as you go to the next gear the revs will drop as the clutch bites. When changing down it would be helpful if I wasn’t already rev matching or heel and toeing.
I noticed exactly the same, more so as I drive the car progressively harder. As you say, with some concentration you can lessen it and it could be viewed as part of the driving engagement and challenge but in reality it may become a minor annoyance...
 

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Sorry can someone explain to me what is the purpose of Rev Hang? Why did Lotus design it as such? I saw online its to do with emissions. But really? Is there no way to eliminate it?

Does Porsche do this on their Caymans?

How bad is it in the Emira?
 
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Nova

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Do the different driving modes affect rev hang or is it all the same?
 
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kitkat

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Sorry can someone explain to me why the Lotus has Rev Hang and what is the purpose of it? Why did Lotus design it as such?

From what I understand lifting off the throttle immediately causes the fuel mixture to becomes lean -- this increases NOx -- and comes across as an increase in emissions. Slowly reducing the throttle prevents this condition.

Do the different driving modes affect rev hang or is it all the same?

Touring and Sport both had it for me, didn't get a chance to try Track -- @Emirahep do you have any input here?
 
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Emirahep

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From what I understand lifting off the throttle immediately causes the fuel mixture to suddenly becomes lean -- this increases NOx -- and comes across as an increase in emissions. Slowly reducing the throttle prevents this condition.



Touring and Sport both had it for me, didn't get a chance to try Track -- @Emirahep do you have any input here?
No difference to Rev Hang in Tour or Sport. Still running in so haven’t tried Track yet.
 

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