7MT Extreme Rev Hang

[Boreal]

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[406g]

Can you take video?

 

[bronco100]

Please just re-read the first paragraph of the original post until you understand what OP is talking about.

Thank you, someone with reading comprehension haha.

 

[bronco100]

Mine for sure hangs similar to what you are saying. RPMs drop faster from higher revs but seem to stop right around 2K.

It is noticeable at times but I'm generally I'm not driving hard enough to notice. I would bet driving style is a big part of it and you notice it much more coming from that BMW.

Yes, especially since my BMW is drive by cable and also has a lightweight flywheel. I think I might get that Bronbuster South Bend clutch with the lightweight flywheel for my Bronco. I suspect it’ll help a lot.

 

[SPITmadFIRE]

It's amazing to me how people can drive a vehicle and just be completely oblivious to certain aspects of it.

Is this your first high-compression, forced induction manual car? My 7MT Badlands has less rev-hang than the other handful of manuals I've owned and driven

 

[bronco100]

Is this your first high-compression, forced induction manual car? My 7MT Badlands has less rev-hang than the other handful of manuals I've owned and driven

Yes… I’ve owned and driven a large number of other manuals but all naturally aspirated.

 

[SPITmadFIRE]

That's most likely why it feels so different to you. You don't have to wait for the revs to drop before shifting up, you can simply clutch-out a little bit slower than you're used to while letting up on the gas just slightly before pulling out of gear. The ECU will compensate.

 

[PWillette]

After further research..!

First of all: idles at 800-1200. Seems pretty high to me.

Second of all, and this is quite astounding to me: Clutch out in first gear while I’m giving it no gas does not stall the car. In fact the car just starts moving. This means it must be getting some throttle input without me doing anything right?
Anyone else with a MT that can test that? It definitely should stall right??

Actually no, it shouldn't stall...there's a video here on the forum...when you start to let out the clutch the RPMs actually start to increase assisting take off. I tried it and it's actually pretty cool for crawling.

 

[harpo]

I don't notice the rev hang on my Bronco. I do know what you are talking about though as my subaru has it, and even after 5 years of driving it, it still bugs me...

 

[Brnzbronc]

Tomatoe, tomato how ever you say it it’s the same thing. Rev hang and rev matching is the same thing. It’s Just goes about how you explain it. Manufactures call it rev matching people that don’t like it call it rev hanging. The 2.3 also has a heavy crank hints why it’s slow to rev up also why it’s slow to come down on the revs. Mustang and focus builders have lightens cranks if you want to go that route but no vehicle is ever going to be perfect unless you build to to fit your liking.

 

[bronco100]

Tomatoe, tomato how ever you say it it’s the same thing. Rev hang and rev matching is the same thing. It’s Just goes about how you explain it. Manufactures call it rev matching people that don’t like it call it rev hanging. The 2.3 also has a heavy crank hints why it’s slow to rev up also why it’s slow to come down on the revs. Mustang and focus builders have lightens cranks if you want to go that route but no vehicle is ever going to be perfect unless you build to to fit your liking.

How is it at all the same thing? I'm not referring to when the RPM's drop and then stay at a certain amount for a second. I'm referring to the amount of time they take to drop.

 

[Brnzbronc]

How is it at all the same thing? I'm not referring to when the RPM's drop and then stay at a certain amount for a second. I'm referring to the amount of time they take to drop.

That’s what rev matching does .. you press the clutch in the revs hold for about 3-5 seconds. If you hold the clutch in long enough it will drop. So I played with the drive settings cause the debate was bugging me. So the rev match or whatever you guys want to call it has a significantly greater occurrence under the 2200 rpm range the greater the rpm the less it does it. This is seen in normal mode and in fuel efficiency mode it does it more. In Sport mode I hardly notice the rev match/rev hang at all and if you double clutch shift it doesn’t do any rev matching. These are my findings not trying to argue or anything just giving my findings and information. If you’re shifting and it holds longer than a couple seconds then there might be a programming update . I don’t know if the computers on the manuals have a learning curve to peoples driving characteristics like the automatics, if you have forscan you can reset the computer learning and see if that changes it.

 

[bronco100]

That’s what rev matching does .. you press the clutch in the revs hold for about 3-5 seconds. If you hold the clutch in long enough it will drop.

Yes, I'm aware of that - that's not what I'm referring to - and that's only a small part of what rev matching is. You can rev match in any manual car but not every manual car holds the revs like that. That's beside the point though...

I'm not referring to really any of the things that you mention here. Nothing regarding "holding" the revs. Sorry if I didn't communicate that clearly. What I am referring to is the time it takes for the revs to drop. Does that make sense?

 

[bronco100]

Here's a scenario for those having difficulty understanding:

You are accelerating from a stop. 1st gear. 4k RPM. You want to shift up. Clutch in. One second later, the revs have dropped to 3k. Another second, and they are at 2k. You can now shift smoothly into 2nd gear. Clutch out. On throttle.

The issue, in case it was difficult to comprehend all that, was holding in the clutch for 2 full seconds in order to shift smoothly. Yes you have to do that on all manual Ford Broncos. Yes even if you haven't noticed that in yours, it is still the case on yours.

Maybe it's normal on a lot of new manual cars. The reason for it is not relevant. What difference does it make? The point is that it should not be normal, nor acceptable. That's 2 seconds that you are not sending power through the drivetrain. Basically just coasting. Every time you shift.

When you are trying to accelerate from a red light this can be quite annoying to other drivers behind you who observe you start to go when the light is green, and then once you reach about 15mph and begin to shift up, they perceive that you are no longer accelerating.

I'm pretty sure I've explained all this several times in this thread but I guess some people can't wrap their head around it.

 

[JerryC]

after reading this thread I paid attention to how I was driving. today I shift slowly, taking about two seconds. Shifting slow like that the shifts are smooth as butter. If I go faster they aren't as smooth, I've mentioned some other threads my trans seems to "heavily gated" which I really hope doesn't mean "broken".

As I let the clutch out on the upshift I'm rolling back into throttle as I always have with a manual.

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