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although lib9erty does not recommend that type of shifting but i have 40k miles on a fp t56
I'm sending my t56 out for faceplating soon. It looks like all your doing is lifting off the throttle for shifts? Ever tried not letting off the throttle and shifting? Sorry if it sounds like a stupid question but I read so many different points of view as how to shift a fp trans
You will tear it up if you do that.....but it will shift. It's very violent like that.
I've even tried using the limiter as a ignition cut....that don't work well either. Just not fast enough or maybe tighten up the drop in the limiter to get it to act smooth. But that woul kinda suck anyway. You really need it to cut when you pull the shifter vis load cell. I have that but it's a bit touchy to tune. I've tore some **** up trying to get it right.
so for now breathe the throttle to unload the trans pull the gear is the smoothest safest way i have found.
You will tear it up if you do that.....but it will shift. It's very violent like that.
I've even tried using the limiter as a ignition cut....that don't work well either. Just not fast enough or maybe tighten up the drop in the limiter to get it to act smooth. But that woul kinda suck anyway. You really need it to cut when you pull the shifter vis load cell. I have that but it's a bit touchy to tune. I've tore some **** up trying to get it right.
so for now breathe the throttle to unload the trans pull the gear is the smoothest safest way i have found.
I will try that when my trans is in the car. Thanks for the advice
You will tear it up if you do that.....but it will shift. It's very violent like that.
I've even tried using the limiter as a ignition cut....that don't work well either. Just not fast enough or maybe tighten up the drop in the limiter to get it to act smooth. But that woul kinda suck anyway. You really need it to cut when you pull the shifter vis load cell. I have that but it's a bit touchy to tune. I've tore some **** up trying to get it right.
so for now breathe the throttle to unload the trans pull the gear is the smoothest safest way i have found.
You can shift a faceplate WOT clutchless without a power cut, but the clutch is still a huge part of making it work without breaking parts. Basically the slip threshold of the clutch needs to be closely matched to the power being made. This allows the clutch to slip a bit after a WOT clutchless shift, which effectively reduces the violence. Works great in a drag race application, quicker than a power cut.
Here's a graph of wot clutchless faceplate shifts using a conventional 10.5" diaphragm PP with controlled hit/clamp...
The engine/driveshaft ratio trace shows where and how long the clutch actually slipped, as you can see it didn't take much to reduce the violence to an acceptable level.
Grant
Last edited by weedburner; 08-24-2018 at 05:58 PM.
Yea i said ya could...it will shift. You will break ****. It is violent.
get the timing right for lift then shift it all goes smoothly and preserves my ****.
i don't think anyone here has the slipper style clutch you mention. A great way to adjust that hit but not applicable unless errybody has that clutch.
as far as quicker vs a shift cut....you're really starting to split hairs that just don't matter much in a street car. Reliability > .0003.
besides for myself i have a really light clutch. Which is faster than a 10.5 clutch. But it's all splitting hairs unless you have a 50ish lb clutch. Then you definitely need a lighter one.
Last edited by HioSSilver; 08-24-2018 at 01:36 PM.
Without unloading the dogs...no it will not shift nicely. Of course you could be brutal and try and force it but as Hi says, you will break ****.
If you get a shift cut strategy right when under load, then shifts will feel pretty damn smooth to the driver, although ultimately they'll still be pretty harsh on the drivetrain
Yea i said ya could...it will shift. You will break ****. It is violent.
get the timing right for lift then shift it all goes smoothly and preserves my ****.
i don't think anyone here has the slipper style clutch you mention. A great way to adjust that hit but not applicable unless errybody has that clutch.
The run/graph I posted used a conventional 10.5" single disc diaphragm clutch. Most here have that style of clutch. The clutch's initial hit was controlled with a ClutchTamer, with enough delay dialed in to also soften the clutchless shifts.
How does the clutch tamer soften the shifts with out using it? You certainly don't want the clutch slipping the entire way down the track.
i haven't installed mine yet.
No idea how one would even suggest such a device would still be "taming" much beyond launch. It isnt a top fuel/meth were we deliberately slip the clutch the entire track.
Big Hammer used it with good success on his launches...especially on a slippery track.
My clutch likey wouldn't take that much slipping. But it makes up for that with a very low moi and light weight. So there is more than one way to skin a cat here.
I'm sure his device works but it's gonna take tuning and probably not gonna get the on track time it nedds from most of us to make it work properly. For me i don't even have a cage....so they gonna boot me before i get it sorted. I'm more about trying to preserve the car anyway than test some things to the 9th degree. I haven't left off a 2step or on a slick yet.....so plenty to be had w/o trying to slip my clutch into every gear at the moment. And i think that's probably the case for most of us.
There's no doubt slippage will help at launch...although how he wishes to think a device that restricts slave retraction will do anything half way up the track well beyond launch and after clutchless shifts...is a bit of a mystery
And there's also no doubt some clutches will take to being slipped at launch better than others. As to how much that will reduce service life will depend on each application...and as to how repeatable such a system is...again, would depend on each application AND launch, as no doubt heat build up will affect friction for each launch and the amount of slip desired.
Last edited by stevieturbo; 08-25-2018 at 08:22 AM.
When you see engine/driveshaft ratio displayed on a graph, here's what you are seeing...
Along the left side of the graph you will see the scale for the engine/driveshaft ratio. The horizontal parts of the trace itself represent the times that the engine/driveshaft ratio are constant... or mechanically locked together thru the ratio inside the transmission (clutch not slipping). The ratios inside this transmission were 3.17/1.96/1.34/1.00, notice that those numbers match up with the scale numbers along the left side of the graph.
This graph shows that the clutch was first mechanically locked up (E/Ds trace goes horizontal) at 0.795 sec into the run. The total time from when the transmission was pulled out of 1st gear until the clutch was locked up in 2nd gear was 0.223 sec. For the 2/3 shift, that total time was 0.279. The 3/4 shift was 0.212 from the time it was pulled out of gear until the clutch was locked up. Each of those shifts include a very brief period where the transmissions was in neutral, before the next gear was engaged. When you trim that from the numbers, you get the amount of time that the clutch actually slipped between shifts- 1/2 shift slipped 0.19 sec, 2/3 slipped 0.24 sec, 3/4 slipped 0.19 sec. Total actual slip time for all three shifts was 0.62 sec.
As you can see, the clutch does not slip all the way down the track. Total actual "slip time" for the entire run, including launch and all three gear changes, was 1.365 seconds
How is the ClutchTamer able to affect the 1/2, 2/3, and 3/4 shifts when the clutch pedal is not being actuated? The answer is that pedal return after the "hit" point (delay setting) was so slow that the pedal did not return all the way to the top of it's travel until some time after all three shifts were complete. This shows up on the graphs as longer actual slip times after clutchless shifts when the delay setting is increased.
Adding slip/delay to the ClutchTamer settings is a proven way to soften shift violence, that shows up in the graphs as less instant wheelspin after clutchless shifts.
Here's a graph showing the previous clutchless run vs a throwout bearing psi curve with a high ClutchTamer delay setting. As you can see, the ClutchTamer is still holding back some clutch clamp pressure after a single pedal release, for a longer period of time than it took to complete all three shifts...
Grant
Last edited by weedburner; 08-25-2018 at 01:01 PM.
There's no way I'd want my clutch slipping under heavy load for that duration.
For launch and launch only I could understand, but a clutch is not a consumable item for me ! ( at least not in the sense of deliberately trying to burn it up )
When you see engine/driveshaft ratio displayed on a graph, here's what you are seeing...
Along the left side of the graph you will see the scale for the engine/driveshaft ratio. The horizontal parts of the trace itself represent the times that the engine/driveshaft ratio are constant... or mechanically locked together thru the ratio inside the transmission (clutch not slipping). The ratios inside this transmission were 3.17/1.96/1.34/1.00, notice that those numbers match up with the scale numbers along the left side of the graph.
This graph shows that the clutch was first mechanically locked up (E/Ds trace goes horizontal) at 0.795 sec into the run. The total time from when the transmission was pulled out of 1st gear until the clutch was locked up in 2nd gear was 0.223 sec. For the 2/3 shift, that total time was 0.279. The 3/4 shift was 0.212 from the time it was pulled out of gear until the clutch was locked up. Each of those shifts include a very brief period where the transmissions was in neutral, before the next gear was engaged. When you trim that from the numbers, you get the amount of time that the clutch actually slipped between shifts- 1/2 shift slipped 0.19 sec, 2/3 slipped 0.24 sec, 3/4 slipped 0.19 sec. Total actual slip time for all three shifts was 0.62 sec.
As you can see, the clutch does not slip all the way down the track. Total actual "slip time" for the entire run, including launch and all three gear changes, was 1.365 seconds
How is the ClutchTamer able to affect the 1/2, 2/3, and 3/4 shifts when the clutch pedal is not being actuated? The answer is that pedal return after the "hit" point (delay setting) was so slow that the pedal did not return all the way to the top of it's travel until some time after all three shifts were complete. This shows up on the graphs as longer actual slip times after clutchless shifts when the delay setting is increased.
Adding slip/delay to the ClutchTamer settings is a proven way to soften shift violence, that shows up in the graphs as less instant wheelspin after clutchless shifts.
Grant
that's a wide ratio trans. Not sure how applicable that is to t56 like gearing. I can see where it woukd benefit that trans more.
Originally Posted by weedburner
Here's a graph showing the previous clutchless run vs a throwout bearing psi curve with a high ClutchTamer delay setting. As you can see, the ClutchTamer is still holding back some clutch clamp pressure after a single pedal release, for a longer period of time than it took to complete all three shifts...
There's no way I'd want my clutch slipping under heavy load for that duration.
For launch and launch only I could understand, but a clutch is not a consumable item for me ! ( at least not in the sense of deliberately trying to burn it up )
That's why a really lite clutch isn't the quick way down the dragstrip, they are not able to handle whats required to get the job done.
All the engine's power, plus most of the energy released due to ratio changes, is still getting passed along to the input shaft. Only a portion of the released energy is actually getting absorbed by the clutch. Sounds like you think your clutch can't handle that, but how do you know until you try. Any idea how long your clutch currently slips during launch?
All the engine's power, plus most of the energy released due to ratio changes, is still getting passed along to the input shaft. Only a portion of the released energy is actually getting absorbed by the clutch. Sounds like you think your clutch can't handle that, but how do you know until you try. Any idea how long your clutch currently slips during launch?
Grant
As of yet, I've never had the opportunity to test it at a proper drag strip. And on airfields etc...I do try and slip a little to soften launch as traction is non existent. Obviously release time will vary...and as to how much actual slip...impossible to tell as it almost always results in wheelspin at such venues.
But as an example from the last run I did clutch release took around 1.2s ( from max hydraulic pressure to zero )...although actual drive bite point to full release was around 0.9s
It could of course be a lot slower and that may well help...but given these launches are at very low rpm, again due to the lack of grip...it really isnt important just now. I may try something at a later date.
But at a proper strip, if and when I get the chance, I'll just launch it hard.
08-23-2018, 06:07 PM
