Rpms not dropping fast enough when speed shifting

[Blake5]

When taking off from a stop and speed shifting from 1st to 2nd gear my rpms aren't dropping fast enough to catch up to my shift and cause me to slip the clutch instead of dumping it causing a slow shift. MT-82 transmission with only a catback exhaust installed.. Is anybody else having this problem or know the solution?

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[Chad11491]

I've noticed they'll hang and literally just sit there. I'm wondering if it's something in the stock tune.

 

[brandonsmash]

I believe this is a known issue, and is less of an issue than a "feature."

 

[derieuz]

Momentum from the engine, light weight harmonic damper, flywheel, and clutch will help this. Part of this is also "safety" from ford so inexperienced drivers don't break it prematurely.. Haven't heard anything about tuners releasing this "rpm hold", I've looked for ages

 

[Horse]

I asked Torrie (Unleashed Tune) if he could do anything about the rev hang, and he did answer. Some of his customer (at least 1 that I know of) tried and seemed to like it (at the time). It's in the V6 forum (click the link below)

http://www.mustang6g.com/forums/showthread.php?t=26050&page=22

 

[Higgs Boson]

maybe I don't understand the question, but if you are "speed shifting" how can you expect the RPMs to drop at all? isn't that the point of "speed shifting?" no RPM drop?

I'm also missing why you feel the need to slip the clutch because of this.....

Are you letting off the gas and pushing in the clutch or are you keeping it floored for a "power shift?"

If you mean to be pulling the foot off the gas to shift and just trying to shift fast but in a regular "gas off" manner then you are probably off on throttle/clutch pedal timing and getting the clutch in faster than getting off the gas and RPMs are rising or not falling.

If you are power shifting with the foot on the gas then you're just too slow, lol.

If you are doing a lazy, fast, gas off shift (and expecting the RPMs to drop, which makes more sense) then yes, as mentioned, the "Return to Idle" or dashpot (not used anymore, torque based now, dashpot is old airflow based term) is leaving the throttle blade slightly open to slow the RPM decline (and in some cases allow a smoother transition to the next gear).

In any case, I think you might just be "doing it wrong."

 

[kz]

Momentum from the engine, light weight harmonic damper, flywheel, and clutch will help this. Part of this is also "safety" from ford so inexperienced drivers don't break it prematurely.. Haven't heard anything about tuners releasing this "rpm hold", I've looked for ages

It's been discussed here many times. Rev hang for fuel economy, part of the stock tune. Feature, not a bug.

 

[dev1360]

What about clutch protection, could that be cutting power, making it feel jerky?

 

[Blake5]

maybe I don't understand the question, but if you are "speed shifting" how can you expect the RPMs to drop at all? isn't that the point of "speed shifting?" no RPM drop?

I'm also missing why you feel the need to slip the clutch because of this.....

Are you letting off the gas and pushing in the clutch or are you keeping it floored for a "power shift?"

If you mean to be pulling the foot off the gas to shift and just trying to shift fast but in a regular "gas off" manner then you are probably off on throttle/clutch pedal timing and getting the clutch in faster than getting off the gas and RPMs are rising or not falling.

If you are power shifting with the foot on the gas then you're just too slow, lol.

If you are doing a lazy, fast, gas off shift (and expecting the RPMs to drop, which makes more sense) then yes, as mentioned, the "Return to Idle" or dashpot (not used anymore, torque based now, dashpot is old airflow based term) is leaving the throttle blade slightly open to slow the RPM decline (and in some cases allow a smoother transition to the next gear).

In any case, I think you might just be "doing it wrong."

"Speed shifting" as in fast shifting but still letting off the gas. My timing isn't off, but I now see it's factory throttle hang. Obviously you didn't understand the question, lol

 

[Higgs Boson]

"Speed shifting" as in fast shifting but still letting off the gas. My timing isn't off, but I now see it's factory throttle hang. Obviously you didn't understand the question, lol

there is no throttle hang during speed shifting. you aren't shifting fast enough.

RPMs only hang when you shift too slowly. a better way to put it is, I don't understand why you're asking the question, but now I know.

post a video of you shifting.

 

[Horse]

The OP wants to shift fast while still matching (or trying to match) the engine rpm with the next gear. In the case of shifting up, we need to wait for the engine rpm to drop to the right value before engaging the clutch. But, with S550 factory tune, the engine rpm hangs there for a longer time than optimal.

It is not that the OP is slow; rather, it is the engine that is too slow in dropping its rpm. Thus the OP has to wait for the engine rpm to drop, hence the OP's question.

Why? because smoothness.

We are not talking about power shifting where you intentionally keep the rpm high for acceleration.

 

[dev1360]

This whole thread is full of fail.

 

[Higgs Boson]

The OP wants to shift fast while still matching (or trying to match) the engine rpm with the next gear. In the case of shifting up, we need to wait for the engine rpm to drop to the right value before engaging the clutch. But, with S550 factory tune, the engine rpm hangs there for a longer time than optimal.

It is not that the OP is slow; rather, it is the engine that is too slow in dropping its rpm. Thus the OP has to wait for the engine rpm to drop, hence the OP's question.

Why? because smoothness.

We are not talking about power shifting where you intentionally keep the rpm high for acceleration.

That would be called Regular Slow Shifting......

Shifting fast AND waiting for the rpms to drop to a matched rpm is not a thing ever anywhere on any car. By definition, the two are mutually exclusive.

 

[dev1360]

[ame]https://vimeo.com/157085067[/ame]

Fast shifting, while lifting?

 

[Horse]

That would be called Regular Slow Shifting......

Shifting fast AND waiting for the rpms to drop to a matched rpm is not a thing ever anywhere on any car. By definition, the two are mutually exclusive.

Only partially agree, b/c of majority of the modern cars made these days.

But fast shifting and rpm matching are not mutually exclusive by definition.

By a tune, the rev hang can be cured (see my post above, with a link to another post). Additionally, one can make the flywheel lighter. This way (e.g., the flywheel having the right weight), you can shift fast while the rpm will still match.

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