[Merlin509]

I get this strange vibration in my clutch pedal under hard acceleration when I let off to shift. Does anyone else get this?

 

[Flying Dutchman]

Clutch pedal

I had a vibration in my clutch pedal after I bought my 2010. I tightened up the nut on the bolt that the pedal pivots on. 12k miles later and everything is still quiet.

 

[dodgetime]

I get this strange vibration in my clutch pedal under hard acceleration when I let off to shift. Does anyone else get this?

if you are under hard acceleration, don't let off between gears to shift keep the right foot planted and keep banging until your satisfied

 

[noz34me]

if you are under hard acceleration, don't let off between gears to shift keep the right foot planted and keep banging until your satisfied

Yep, if you know how to speed shift you can make the shifts faster than any of the slush box trannies (autos). Last time I tried it was with my GTO and besides the burnout at the beginning, I was squealing tires in 2nd and 3rd. Beat a very nice Trans Am at the beach. Thank God there were no police around. I've since reformed.

If you don't know what you're doing, trying this will surely guarantee a visit to your dealer's friendly service dept.

 

[noz34me]

Is it possible to go through your gearing faster in a manual than in an auto? I mean, is there a safe shifting technique that can be done?

I'm not that up to date on newer automatic specs as far as shift times. Back in the days of TH350 and TH400 (GM) trannies, yes you could shift faster (theoretically and some people in practice) than the auto would shift. With a good clutch and good driver, the gear engagement would also be more definitive. (Hence the term slush box for auto trannies). Each shift can almost make you feel a leap forward.

So yes, you could possibly shift faster than the auto changes gears. That said, as another post mentioned, it requires basically mashing the pedal to the floor and keeping it there though all the gears. You can imagine the hazards involved here. It means hitting the clutch and releasing very quickly and at the same time hitting the next gear with your shifter.

It is very exciting and can be very specatacular whether you do it right or not; just in a positive or negative way.

I am ABSOLUTELY NOT advocating that ANYONE try this.

 

[SAPhotoman]

Speed Shift

If someone wanted to try speed shifting (big IF at your own risk), you might try it at a low throttle setting to see if your speed shifting skill is up to par. I used to do it on my motorcycle just playing around. BIG DISCLAIMER: I've never owned a manual car, so take this accordingly.

 

[FFchris]

i had a '68 340 4spd dart i would race that way, but we ground every 2nd tooth off of the syncro's . (purposely ground them off, we termed this a "slush box" because it was great on the track but crap to drive on the street)

 

[noz34me]

So do you mean literally applying WOT the whole time from Gear 1 and never letting off of it, while still clutching and shifting (while suppressed on the gas the whole time)?

Holy crap it sounds like suicide on your trans!

It certainly can be. Not something I would try with a $35-$40K car. Especially given that a lot of the manual tranny issues are not covered under warranty.

Again, I am not advocating trying this for anyone!

 

[noz34me]

OK, I can see I opened up a can of worms here, and someone is going to be hellbent to try it only to be pissed when they ruin either their gearbox, engine, or clutch. So here' s a revised statement:

Under no circumstances should anyone try to speed shift. I made it all up. It's an impossible task that is impossible to perform without severe damage to any car, be it a $3K beater to a $200K sports car.

 

[noz34me]

Fair enough lol, so I guess the most optimal process is still:
1. Let off Gas
2. Suppress Clutch
3. Shift
4. Let off Clutch while Applying Gas
5. Floor it :bigthumb:

Exactly, and also:

1. Come to a complete stop at stop signs
2. Look both ways before crossing traffic
3. Observe and obey all road signs and markings
4. Remember your Mom on Mothers Day

 

[Merlin509]

For what it's worth, speed shifting is just shifting fast with full clutch and lifting throttle. Power shifting is no throttle lift and jabbing the clutch when shifting. A STD Tremec will tolerate this for some time if done correctly and it's fairly safe because the rev limiter will prevent you from over revving if you miss the gear. That said, power shifting will wear the syncros faster over time and there's always the chance of serious damage if you really mis-time it (commitment is the key).

Power shifting is only worth it if your at the track and trying to shave hundreths off your time. You don't gain much over "speed shifting" on the street. It does, however, sound very cool when done right.

 

[aarcuda]

add in the fact that these cars automatically close the throttle on you when you hit the clutch......

 

[Merlin509]

add in the fact that these cars automatically close the throttle on you when you hit the clutch......

I haven't noticed that. I've power shifted 3-4 a few times and it didn't seem to close throttle, but I wasn't really paying that much attention.

The rev limiter is set so low on these cars, that it's almost always going to bounce off the limiter if you're power shifting anywhere close to the red line. With no limiter, revs will typically jump 200-300 when shifting with WOT.

 

[aarcuda]

it happens in the blink of an eye. I can see it when I datalog. I cant feel it when i powershift (rpms seem to increase during the clutching). someone o n here actually made a video of it blinking closed and reopening during the shift

 

[Merlin509]

it happens in the blink of an eye. I can see it when I datalog. I cant feel it when i powershift (rpms seem to increase during the clutching). someone o n here actually made a video of it blinking closed and reopening during the shift

Not a big deal as long as it doesn't create a noticeable lag.

I know that they're trying to protect us from ourselves, but it would be nice if they put all these little "features" in a menu and allow us to easily turn them off or adjust them as we desire. It's a little too "big brother" for me, but I guess it protects the warranty (although, I bought the car second hand, so the PT warranty is void anyway).

 

[Merlin509]

Basically, speed shifting is like normal shifting, but doing is as fast as you can. You don't necessarily have to lift all the way off the throttle or clutch to the floor. Just practice and you can get very fast without endangering your trans.

Power shifting is shifting at full throttle without lifting and just stabbing at the clutch at the same time you shift. You're just making a quick stab at it (again, not necessarily all the way in) synchronized with the shift. I wouldn't recommend doing this often with a stock shifter. You really should have a good quality short throw shifter WITH STOPS. If you don't have adjustable stops, you'll put a lot of torque on the internal shift rods and shifter assembly. If there really is a throttle cutout when clutching, power shifting won't have any benefit (not that there's a huge difference anyway).

To be honest, I've always found Tremecs to be a little notchy and tough to power shift, even with the best aftermarket shifters. Just stick with practicing the normal shifting method as fast as you can. Remember that you don't need to completely lift throttle when speed shifting and you only need to depress the clutch pedal to the point where your clutch is slipping, not all the way to the floor. It should all be one smooth and quick motion.

 

[SAPhotoman]

To be honest, I've always found Tremecs to be a little notchy and tough to power shift, even with the best aftermarket shifters. Just stick with practicing the normal shifting method as fast as you can. Remember that you don't need to completely lift throttle when speed shifting and you only need to depress the clutch pedal to the point where your clutch is slipping, not all the way to the floor. It should all be one smooth and quick motion.

I'd like to see a video of that speed shift!

 

[Merlin509]

I'd like to see a video of that speed shift!

I think if you run a search on YouTube, you'll find several.