Quick Change Shift Kit Question

[elemgee]

Am thinking about ordering a quick change shift kit, but am curious if there is any negative effect on the already weak transmission. The last thing I want to do is make it weaker. Anyone know? I've read some posts on it but nothing seemed to really address this question. Thanks.

[SoCal LS-L]

The quick change helps prolong the life of the transmission actually. Long smooth gear changes actually wear components out faster.

[b3lha]

Can anybody explain how disabling the engine torque reduction signal is good for the transmission? Because I would expect the exact opposite.:confused:

Presumably, the clutches slip during a gear shift, and the more torque you apply to them when they are slipping, the quicker they will wear out.

[Wikedjuggalo]

Duck and cover! :lol:

[siceclipse]

Here we go....

[immortal_suby]

Have not had a problem with mine. I love it. Had it in since June 2008. I imagine if you abused the transmission by regularly hammering out full throttle shifts with no torque reduction you might break something.

Harvey specifically states not to put one on a failing tranny or without a good resistor in the quick change thread on the svxwf.


The surge in the Torque peak is due to the torque converter, multiplying torque due to the difference in engine/transmission speed, it is not a shock loading, it is actually a very nice surge:)

I also recomend that it is only fitted to a working transmission, with a well adjusted brake band, and a working AWD.

[Trevor]

Can anybody explain how disabling the engine torque reduction signal is good for the transmission? Because I would expect the exact opposite.:confused:

Presumably, the clutches slip during a gear shift, and the more torque you apply to them when they are slipping, the quicker they will wear out.

This is particularly the situation during down shifting for acceleration, after applying more than third throttle. The claim is that increased line pressure, the result of disabling control of solenoid "A", will prevent slip and damage to friction surfaces. However, it can not be denied that shock loads throughout the transmission train, will be much increased.

A quite drastic change is made in respect of the original design parameters. Were Subaru engineers stupid?:confused:

[immortal_suby]

How does a WRX or forester XT 4EAT deal with this shock load without using torque reduction?

[1986nate]

How does a WRX or forester XT 4EAT deal with this shock load without using torque reduction?

Change in transmission designs. Those use PhaseII transmissions that have had significant changes from the phaseI transmissions.

Not trying to argue for or against the quick change, just giving response to your question.;)

[oab_au]

Am thinking about ordering a quick change shift kit, but am curious if there is any negative effect on the already weak transmission. The last thing I want to do is make it weaker. Anyone know? I've read some posts on it but nothing seemed to really address this question. Thanks.

Giday Elemgee, The Quick Change has been used on about 70 SVX so far, in 6 different countries.. There have been no reported problems, due to its use. I would not recommend its use on a transmission that is already experiencing problems. If it is fitted to a normally good box, it can help to extend the transmissions life, but it cannot prevent the driver from abusing the car.

Quote:
Originally Posted by immortal_suby
How does a WRX or forester XT 4EAT deal with this shock load without using torque reduction?

Nate wrote: Change in transmission designs. Those use PhaseII transmissions that have had significant changes from the phaseI transmissions.

Nate the early WRX 94 to 97 and the 92 RS Turbo models here in Australia are fitted with the Phase 1 trans the same as the SVX . These did not use a torque cut, and have not had any problems that can be attributed to not having it.

B3lha wote: Can anybody explain how disabling the engine torque reduction signal is good for the transmission? Because I would expect the exact opposite.

Presumably, the clutches slip during a gear shift, and the more torque you apply to them when they are slipping, the quicker they will wear out.

Phil to understand why this is so, you need to understand why Subaru did it in the first place.

When this transmission was used in the Sporty WRX and RS Turbo, the change was fast and solid, just what you would expect of a Sporty car. When the SVX was designed it was aimed at the higher end of the Luxury Grand Touring market. The same fast solid change did not suit this market, so they programmed the TCU to lower the line pressure during the change, to remove the solid engagement.

Because the reduced pressure would allow the clutch and band to do a lot of slipping to smooth the change, they turned the Engine torque down to prevent excessive wear. The result was that silky smooth gear change that suited the Luxury profile that they wanted, but at the expense of clutch and band wear.

As the Quick Change prevents the line pressure from being lowered during the change, there is no need to reduce the engine torque. So it converts the gear change to the same fast solid shift, as we had with the Sporty models.

Any fears of the transmission having shock loadings, is only in the minds of those that have not driven a car that is fitted with a Quick Change.:)

Harvey.

[Trevor]

Phil to understand why this is so, you need to understand why Subaru did it in the first place.

When this transmission was used in the Sporty WRX and RS Turbo, the change was fast and solid, just what you would expect of a Sporty car. When the SVX was designed it was aimed at the higher end of the Luxury Grand Touring market. The same fast solid change did not suit this market, so they programmed the TCU to lower the line pressure during the change, to remove the solid engagement.

Because the reduced pressure would allow the clutch and band to do a lot of slipping to smooth the change, they turned the Engine torque down to prevent excessive wear. The result was that silky smooth gear change that suited the Luxury profile that they wanted, but at the expense of clutch and band wear.
Harvey.

The above statement constitutes no more than a personal opinion, unless additional published supporting evidence is quoted and is verified.

[immortal_suby]

The above statement constitutes no more than a personal opinion, unless additional published supporting evidence is quoted and is verified.

Wouldn't the exclusion of torque reduction on turbo models equipped with a phase 1 4EAT serve as proof that subaru was not concerned with the longevity of the transmission?

I'll have to dig up my road and track guide to the svx to verify, but IIRC there was a section devoted to the pursuit of a seamless gear change on the svx to promote the luxury car ideal. Of course that is not fact as it is journalism, but the fact that concurrent subaru models of similar weight and torque did not use torque reduction while the svx did is evidence to validate the article.

[immortal_suby]

Wouldn't the exclusion of torque reduction on turbo models equipped with a phase 1 4EAT serve as proof that subaru was not concerned with the longevity of the transmission?

I'll have to dig up my road and track guide to the svx to verify, but IIRC there was a section devoted to the pursuit of a seamless gear change on the svx to promote the luxury car ideal. Of course that is not fact as it is journalism, but the fact that concurrent subaru models of similar weight and torque did not use torque reduction while the svx did is evidence to validate the article.

edit: here is the page from the R&T guide

"Gear changing was brought to luxury coupe levels of smoothness by instituting a torque management program which cuts fuel to half of the engine's cylinders on the 1-2 gearshift"

http://www.svx-iw.com/svxiw/road_track/images/65.jpg

[b3lha]

Phil to understand why this is so, you need to understand why Subaru did it in the first place.

When this transmission was used in the Sporty WRX and RS Turbo, the change was fast and solid, just what you would expect of a Sporty car. When the SVX was designed it was aimed at the higher end of the Luxury Grand Touring market. The same fast solid change did not suit this market, so they programmed the TCU to lower the line pressure during the change, to remove the solid engagement.

Because the reduced pressure would allow the clutch and band to do a lot of slipping to smooth the change, they turned the Engine torque down to prevent excessive wear. The result was that silky smooth gear change that suited the Luxury profile that they wanted, but at the expense of clutch and band wear.

As the Quick Change prevents the line pressure from being lowered during the change, there is no need to reduce the engine torque. So it converts the gear change to the same fast solid shift, as we had with the Sporty models.


Maybe that's true. I think that firming up the shifts by recalibration of the line pressure is probably a very good idea and might help to extend the life of the transmission.

But the less torque you apply to the clutches, the less they will slip and the longer they will last. It seems to me that reducing the torque during a shift must a good thing for gearbox longevity. Conversely, disabling the torque-cut signal must surely subject the clutches to more torque, more slip and more wear than leaving it alone.

I accept that the primary goal of the QS device is performance, rather than gearbox longevity. But it's stretching things a bit far to claim that it will definitely make the transmission last longer. Maybe in a few years time, when people have done 80000+ miles with a QC, we'll be able to look at the failure stats and say whether it is better or worse. But right now it's just speculation either way.:)

[NiftySVX]

Maybe that's true. I think that firming up the shifts by recalibration of the line pressure is probably a very good idea and might help to extend the life of the transmission.

But the less torque you apply to the clutches, the less they will slip and the longer they will last. It seems to me that reducing the torque during a shift must a good thing for gearbox longevity. Conversely, disabling the torque-cut signal must surely subject the clutches to more torque, more slip and more wear than leaving it alone.

I accept that the primary goal of the QS device is performance, rather than gearbox longevity. But it's stretching things a bit far to claim that it will definitely make the transmission last longer. Maybe in a few years time, when people have done 80000+ miles with a QC, we'll be able to look at the failure stats and say whether it is better or worse. But right now it's just speculation either way.:)

I do not have any experince with the quick shift product, and I do not personally believe it to be detrimental to any soft transmission parts, but it could be argued that the planetary gears or the lip seals could be damaged by it. I do not believe this is really relevant, because we don't see those kind of failures on these. What's more, what I have had done is surely more trying on those components than any electric mod, and I believe it to be within design limits.

MY OPINION, as a person who has extensive experience with this transmission (but again, absolutely zero with the QC product) is that the torque control signal was put in place to make the thing hold together AND to make it shift better, though I find it odd that it does not occur on the 1-2 shift which is where I think it is needed the most as far as feel goes. Further, I believe that a modification of the valve body to increase base line, apply pressure to the band, high clutch, drain from those areas to compensate for the added flow, and flow thru the cooler circuit could help with the longevity of the transmission, and that such modifications make the QC essentially unnecessary by achieving the same results. I believe a member here has made a product, which, like any modification, lacks the testing that an OEM part would, but that is a product to add to our lineup of impressive feats that we as a community have achieved together in these past 10 years that we have been together on the network. This is to be appreciated, and to be purchased and used by those who choose to use it. From what I have heard, the product does what it is supposed to.

Why, Nifty, did they not do this from the factory, you may ask, stating an excellent opinion that the pump in this trans is too weak, and I would answer "because it killed my fuel economy by an indeterminable amount that is somewhere between .2-.9 MPG.

[oab_au]

Maybe that's true. I think that firming up the shifts by recalibration of the line pressure is probably a very good idea and might help to extend the life of the transmission.


Phil the line pressure is set by the throttle position, you may raise be recalibration, but it is still lowered during the change.

But the less torque you apply to the clutches, the less they will slip and the longer they will last. It seems to me that reducing the torque during a shift must a good thing for gearbox longevity. Conversely, disabling the torque-cut signal must surely subject the clutches to more torque, more slip and more wear than leaving it alone.

The maximum amount of torque that is applied to the box is when you do a full throttle start in first. The torque is not cut, and the line pressure is not lowered.

I accept that the primary goal of the QS device is performance, rather than gearbox longevity. But it's stretching things a bit far to claim that it will definitely make the transmission last longer. Maybe in a few years time, when people have done 80000+ miles with a QC, we'll be able to look at the failure stats and say whether it is better or worse. But right now it's just speculation either way.

Well I don't think I made that claim:confused:. but what I can say is that preventing the lowering of the line pressure during the change, will reduce the wear on the brake band and clutches, and if we are going to do that we may as well let the converter do the work it is supposed to do :)

Harvey.

[oab_au]

The cutting of the engine torque during the change not only produces the ‘do nothing’ between gears, it robs us of the Torque converters action that should happen on the change. By cutting the engine torque the converter can only act as a soft coupling between the engine and box, the gear ratio changes and the engine has to pull that higher ratio, that can bog it down, eg 1st gears 2.78 to 2nd gears 1.54.

With the torque cut removed, the converter is allowed to handle the full engine’s torque, it will act as a variable gear ratio between the engine and the gearbox that can change the ratio from 1:1 down to 1.9:1. So that when the change is made from 1st to 2nd, instead of the 2nd gears ratio of 1.54, the converter can reduce this to 1.9 X 1.54, to 2.85 then as the converter brings the engine speed down to the lower gear, the converter will reduce this to 1.54. Because the converter reduces the gearing, it also multiplies the torque to give that surge on the change, that only a Quick Change driver can enjoy.

Harvey.

[y2daniel1981]

I do not have any experince with the quick shift product, and I do not personally believe it to be detrimental to any soft transmission parts, but it could be argued that the planetary gears or the lip seals could be damaged by it. I do not believe this is really relevant, because we don't see those kind of failures on these. What's more, what I have had done is surely more trying on those components than any electric mod, and I believe it to be within design limits.



Next time I'm in OKC I'll be more then glad to give you a ride in mine, not sure when the next time will be though (usually about every other month.) I will however be in Stillwater Saturday night

[oab_au]

I do not have any experince with the quick shift product, and I do not personally believe it to be detrimental to any soft transmission parts, but it could be argued that the planetary gears or the lip seals could be damaged by it. I do not believe this is really relevant, because we don't see those kind of failures on these. What's more, what I have had done is surely more trying on those components than any electric mod, and I believe it to be within design limits.
.

I'll have to find a QC member around your area for you to try it, I think you will be surprised. :)

MY OPINION, as a person who has extensive experience with this transmission (but again, absolutely zero with the QC product) is that the torque control signal was put in place to make the thing hold together AND to make it shift better, though I find it odd that it does not occur on the 1-2 shift which is where I think it is needed the most as far as feel goes. .

I disagree with you on the "holding together bit". The same box has done service in the turbo models that use it, without the torque cut. The torque cut and the pressure lowering is on all shifts.

I believe that a modification of the valve body to increase base line, apply pressure to the band, high clutch, drain from those areas to compensate for the added flow, and flow thru the cooler circuit could help with the longevity of the transmission, and that such modifications make the QC essentially unnecessary by achieving the same results.

Yes modifications to the valve body to improve the flow for cooling and lubrication, can only help the transmission, but the valve body mods won't prevent the TCU from reduce the pressure, regardless of the valve body mods, the engagement pressure will still be lowered to allow slipping. The QC does that.:)
Increasing the base line, line pressure will mean that the pressure applied to the B and C solenoids will also be higher that can cause lock-up clutch drag, and transfer clutch binding.

Harvey.

[NiftySVX]

For some reason I thought it was only on the 3-4. Hm, I can't remember everything :rolleyes: but I don't know. I don't see it hurting transmissions is all. I'd put it on my car, but by 1-2 shift is already so hard it squeeks the mounts :lol:

[Trevor]

Phil the line pressure is set by the throttle position, you may raise be recalibration, but it is still lowered during the change.

Line pressure is not “set by the throttle position,’’ as you repeatedly claim. Line pressure is set as a result of the TCU computing several inputs, with throttle position being but one.

Obviously if the calibration is adjusted and the overall pressure raised, the “lowered” pressure must also be raised.

The maximum amount of torque that is applied to the box is when you do a full throttle start in first. The torque is not cut, and the line pressure is not lowered.

The situation prevailing when starting is in no way relevant. The point raised was the possibility of clutch slip, when clutches operate as a result of gear changing, at which point, torque reduction most certainly proves an advantage.

Well I don't think I made that claim:confused:.

Statement made within previous post 10. --- “If it is fitted to a normally good box, it can help to extend the transmissions life”

[Trevor]

The cutting of the engine torque during the change not only produces the ‘do nothing’ between gears, it robs us of the Torque converters action that should happen on the change. By cutting the engine torque the converter can only act as a soft coupling between the engine and box, the gear ratio changes and the engine has to pull that higher ratio, that can bog it down, eg 1st gears 2.78 to 2nd gears 1.54.

With the torque cut removed, the converter is allowed to handle the full engine’s torque, it will act as a variable gear ratio between the engine and the gearbox that can change the ratio from 1:1 down to 1.9:1. So that when the change is made from 1st to 2nd, instead of the 2nd gears ratio of 1.54, the converter can reduce this to 1.9 X 1.54, to 2.85 then as the converter brings the engine speed down to the lower gear, the converter will reduce this to 1.54. Because the converter reduces the gearing, it also multiplies the torque to give that surge on the change, that only a Quick Change driver can enjoy. Harvey.

It is proposed that it is desirable to have full engine torque, which is further increased by the torque converter, suddenly applied to the transmission “as a surge on the change”. Apparently this added shock load is a sort after and enjoyable feature, “that should happen on the change.”

By contrast, the very reason for including torque reduction feature, is made clear.

[immortal_suby]

It is proposed that it is desirable to have full engine torque, which is further increased by the torque converter, suddenly applied to the transmission “as a surge on the change”. Apparently this added shock load is a sort after and enjoyable feature, “that should happen on the change.”

By contrast, the very reason for including torque reduction feature, is made clear.

Do you care to address the lack of torque control on turbo models using the same transmission? Or would you rather sidestep that point and just pick apart every single thing that Harvey does.

[92 SVX]

Maybe that's true. I think that firming up the shifts by recalibration of the line pressure is probably a very good idea and might help to extend the life of the transmission.

But the less torque you apply to the clutches, the less they will slip and the longer they will last. It seems to me that reducing the torque during a shift must a good thing for gearbox longevity. Conversely, disabling the torque-cut signal must surely subject the clutches to more torque, more slip and more wear than leaving it alone.

I accept that the primary goal of the QS device is performance, rather than gearbox longevity. But it's stretching things a bit far to claim that it will definitely make the transmission last longer. Maybe in a few years time, when people have done 80000+ miles with a QC, we'll be able to look at the failure stats and say whether it is better or worse. But right now it's just speculation either way.:)
I am not an engineer, but some common sense coupled with a smidgen of knowledge leads me to think a higher torque applied will cause less slip.

Take it this way if you try to stop something spinning, if you hold light pressure it takes longer to stop, but if you apply hard pressure it takes considerably less time to stop.

[Trevor]

Do you care to address the lack of torque control on turbo models using the same transmission? Or would you rather sidestep that point and just pick apart every single thing that Harvey does.

Your sarcasm is noted. When I side step a questions as does Harvey, you will have grounds to complain. Meantime please confine yourself to stating fact.

In point of fact, your reference to the different models proves the need for the features incorporated in the SVX transmission. Not by contrast, that the features are superfluous.

The SVX is a much heavier car than the models to which reference has been made, and also includes a higher final drive ratio. Comparison on the grounds suggested is in no way valid and is in fact stupid.

[Trevor]

I am not an engineer, but some common sense coupled with a smidgen of knowledge leads me to think a higher torque applied will cause less slip.

Take it this way if you try to stop something spinning, if you hold light pressure it takes longer to stop, but if you apply hard pressure it takes considerably less time to stop.

A smidgen common sense applied correctly will assist in understanding what is involved. ;)

It would appear that you are thinking of the power involved in closing and holding the friction surfaces in secure contact. The torque referred to is that which must be transferred by the clutches.

The more torque having to be transferred when a clutch closes, the greater the wear. Reducing this torque during gear shifts, therefore has a very real advantage.

[immortal_suby]

The SVX is a much heavier car than the models to which reference has been made, and also includes a higher final drive ratio. Comparison on the grounds suggested is in no way valid and is in fact stupid.

You are much more intelligent than to bring final drive ratio in as a factor. Weight difference is negligible considering cargo and passengers or lack thereof.

[b3lha]

I am not an engineer, but some common sense coupled with a smidgen of knowledge leads me to think a higher torque applied will cause less slip.

Take it this way if you try to stop something spinning, if you hold light pressure it takes longer to stop, but if you apply hard pressure it takes considerably less time to stop.

I think you are looking at it upside down. Using your analogy, the torque is the "spinning force", not the "resisting force". The "resisting force" is the friction of the clutches being pushed against each other by hydraulic pressure. The greater the torque, the more friction you require to resist it.

Increased pressure results in less slip for the same amount of torque (as you correctly said). But increased torque results in more slip for the same amount of pressure.

What Harvey does is increase both torque and pressure but not necessarily by the same amount. So it's hard to say whether there is more or less slip during the very short time period of the gear change.

[Trevor]

You are much more intelligent than to bring final drive ratio in as a factor. Weight difference is negligible considering cargo and passengers or lack thereof.

Again a post limited to sarcasm.

A study of the relationship between RPM, torque and power, will provide an understanding of what is involved. It is also necessary to be conversant with the terms, net and gross, in respect of weight.

Only then can one consider and be aware of the parameters overall, as were presented to the designers of the SVX.

[Trevor]

Let it be very clear that when a “QC” is fitted, immediately after more than one third throttle is applied, regardless of any other function, all control of transmission line pressure via the TCU ceases; i.e. the operative signals from the TCU are locked out and maximum line pressure prevails.

What is more, the “QC’ does not in any way act progressively, as has been claimed. The action is complete and immediate. As soon as a set degree of throttle opening has been applied, from that point on, the operative signals from the TCU are immediately, completely locked out, resulting in continuous uncontrolled, maximum line pressure.

[icingdeath88]

Let it be very clear that when a “QC” is fitted, immediately after more than one third throttle is applied, regardless of any other function, all control of transmission line pressure via the TCU ceases; i.e. the operative signals from the TCU are locked out and maximum line pressure prevails.

What is more, the “QC’ does not in any way act progressively, as has been claimed. The action is complete and immediate. As soon as a set degree of throttle opening has been applied, from that point on, the operative signals from the TCU are immediately, completely locked out, resulting in continuous uncontrolled, maximum line pressure.

As far as progressive vs on-off: I've had the QC on my car for ~1 month now. I'd definitely describe the feel of it as either on or off rather than progressive. Furthermore, there is a quiet click when the QC takes over, which indicates to me that there is a point where something changes. I don't really mind that it doesn't seem progressive though, because generally, I'm either driving hard or I'm driving normal.

[oab_au]

What Harvey does is increase both torque and pressure but not necessarily by the same amount. So it's hard to say whether there is more or less slip during the very short time period of the gear change.

Phil, I think you are just a little bit paranoid about this auto.:D

This is a strong auto. It is designed to do the job by the manufactures. Members have run 100hp shots of Nitrous, LAN ran 140hp shot, the box handles it just fine, nothing broke, or burnt out.
It is Subaru additions that deviate from the designers intentions.

The shift accumulators are designed to firm-up the clutch/band engagement progressively as the throttle is increased. They are feed from the A solenoid's pilot pressure, so as the throttle goes down and the torque increases the line and accumulator pressures increase, and engagement pressure increases to suit the load.

This is how Jatco designed it to work. It is Subaru's "soft shoe shuffle" change, that turns this action down, so that the A solenoid reduces the line pressure, and if that is not enough, it also prevents the accumulators from increasing the engagement pressure.:eek: It is no wonder that there is so much slipping going on, that causes wear and heat.

All the Quick Change does, is to remove Subaru's interference during the change, so that as the throttle is progressively opened, the line pressure, and accumulator pressure, is increased progressively, to suit the throttle opening and load. The way Jatco meant it to work.

The failures that the box had were caused by flaking lining on the torque converters lock-up clutch, that blocked the cooler, so that it lost cooling lube oil flow. The other fault is the very high final drive ratio that they used in the states, coupled with an engine that can pull 4th gear down to 1700 rpm, so that the line pressure got so low the band started to slip and burn.

Harvey.

[oab_au]

Let it be very clear that when a “QC” is fitted, immediately after more than one third throttle is applied, regardless of any other function, all control of transmission line pressure via the TCU ceases; i.e. the operative signals from the TCU are locked out and maximum line pressure prevails.

What is more, the “QC’ does not in any way act progressively, as has been claimed. The action is complete and immediate. As soon as a set degree of throttle opening has been applied, from that point on, the operative signals from the TCU are immediately, completely locked out, resulting in continuous uncontrolled, maximum line pressure.

This can only happen in your mind. It is complete Bull.:tard:

Harvey.

[Trevor]

This can only happen in your mind. It is complete Bull.:tard:

Harvey.


It is you who delivers excrement. What I have stated is exactly correct. Prove otherwise.

[b3lha]

Phil, I think you are just a little bit paranoid about this auto.:D


Yeah. You're right Harv. No question about it.:lol:

But since joining the SVX community, I've had two transmission failures and spent scary amounts of money having them rebuilt. So I think I've earned the right to be a bit paranoid. :(

If I could understand how to properly recalibrate the TCU software for better gearbox longevity, it would be installed on all three of my cars the very next day.

[oab_au]

Yeah. You're right Harv. No question about it.:lol:

But since joining the SVX community, I've had two transmission failures and spent scary amounts of money having them rebuilt. So I think I've earned the right to be a bit paranoid. :(

If I could understand how to properly recalibrate the TCU software for better gearbox longevity, it would be installed on all three of my cars the very next day.

Yes
I can understand your caution. I am very glad I bought a 95 model.

Phil I reckon if we work together, this could all be done in the soft wear.:)

Harvey.

[oab_au]

As far as progressive vs on-off: I've had the QC on my car for ~1 month now. I'd definitely describe the feel of it as either on or off rather than progressive. Furthermore, there is a quiet click when the QC takes over, which indicates to me that there is a point where something changes. I don't really mind that it doesn't seem progressive though, because generally, I'm either driving hard or I'm driving normal.

Trevor's argument lies in the use of the word "progressive".
I first used the word in the thread that he started, before the QC was released, here in May 2008.
http://www.subaru-svx.net/forum/showthread.php?t=44706&page=11

When I said:
The other thing that the SCSK can't do, that the Quick Change achieves is that because the Pilot pressure that the A solenoid regulates, is also used to set the pressure behind the shift accumulators, by keeping this pressure from reducing, it reduces any chance of slip due to the longer engagement time, that the softer accumulator gives, so its action is set in line with the throttle pressure as the whole operation is.
The Quick Changes action is progressive to the throttle position, no change at all on a light throttle, progressively getting firmer with the throttle position.
This is the same as I have stated in this thread, but as Trevor has no knowledge of the workings of the gearbox hydraulics, he could not understand what I said, so he took this word and used it in the context of his own statement, "that it was the QC circuitry that was not progressive."

This is not so. the unit turns on at about 2Volts, and stays that way till it reduces to about 1.7Volts, when it turns off. It has to be this way as the same control port is used for some other things like, low pressure for cranking the engine, and reduces the pressure for low oil temperature.

You can feel the progressive action if you do a 1st to 2nd change on half throttle, then do the same on 3/4 throttle, then again on full throttle. You will feel that the engagement pressure, or the "shift firmness" becomes progressively firmer.:)

Harvey.

[Trevor]

All the Quick Change does, is to remove Subaru's interference during the change, so that as the throttle is progressively opened, the line pressure, and accumulator pressure, is increased progressively, to suit the throttle opening and load.
Harvey.

What you state is absolutely impossible and is in every sense wrong.

Immediately throttle opening exceeds a set point at quarter to third of travel, the “QC” relay operates instantaneously, all control of line pressure is illuminated and solenoid “A” remains closed, resulting in maximum line pressure. The action is sudden immediate and complete. Nothing is in any way progressive. There is absolutely no way pressure is or can be, “increased progressively to suit the throttle opening and load” after the “QC” has operated..

Your next side step will be to claim that is spite of your wrong statement regarding the “QC”, opening the throttle will increase engine speed, and as a result transmission pump speed, which will in turn increase line pressure.

Maximum line pressure is controlled, limited and set by the pilot valve, which regulates the pressure within the pilot feedback loop. This pressure will be reached at a relatively low speeds, in order to ensure an adequate overall maximum, with this to be further reduced as a means of control utilising solenoid "A".

I appreciate that the application of feed back within a control system is beyond your understanding, but without this included hydraulic control circuit, pressure would run away completely at high speeds. (*Refer below to learn in regard the application of a feedback loop.)

N.B. Therefore all control resulting from throttle opening is dependent on the control signal delivered to solenoid “A”, and which the “QC” instantly interrupts and prevents after application of part throttle. Your thoery is impossible.

The second side step will be to claim that after the "QC" acts, solenoid “A” continues to be controlled via the resistor circuit. The reduced voltage delivered by this circuit is insufficient to actuate the solenoid, and is limited to a holding function after the solenoid has been fully actuated, via the main full voltage signal.

Once the full voltage signal is cut by the “QC”, the resistor signal can have absolutely no effect. Solenoid “A” is isolated from the TCU and any form of control is impossible. Again your thoery is impossible.

What I state is fact, based on common sense and logic, as well as practical oscilloscope measurements, with an SVX both static and mobile, as has been carried out by both Phil and myself.

What you claim is illogical and is impossible. You should study and join this site. ---

http://www.alaska.net/~clund/e_djublonskopf/Flatearthsociety.htm

* The answer to this difficult problem utilised within process control equipment, is to provide a feedback loop, established via a feedback signal, whereby control can be balanced/adjusted, even though variables exist. In its simplest form feedback sensing can be down stream, but when this can not be arranged, sensing can be achieved directly from the controlling device.

[Trevor]

This is not so. the unit turns on at about 2Volts, and stays that way till it reduces to about 1.7Volts, when it turns off. It has to be this way as the same control port is used for some other things like, low pressure for cranking the engine, and reduces the pressure for low oil temperature.
Harvey.

The stupid statements and excuses continue unabated.

I state emphatically that I can understand the written word, as my use of language proves. What is more my correct descriptions of the hydraulics involved, show that I have adequate knowledge in this respect.

By contrast the continual publication of wrong and misleading information is proof of a complete lack of knowledge, intelligence and even common sense

N.B. After the throttle is closed and the TPS delivers approximately 2 volts the "QC" turns ON. At this point all control previously available to solenoid "A", is cut and turned OFF.

There is, and can not be, any form of control during further application of throttle.

When the throttle is closed and TPS voltage falls to 1.7 volts, the "QC" turns OFF, and only then is control of line pressure via solenoid "A" restored.

There is not, and can not be, any form of control during the applicable throttle release.

The "QC" does not, and can not, act progressively. Once the "QC" acts,. no further progressive control is possible.

[oab_au]

As I said before this is all crap. Why don't you go and start an argument some where else.

Harvey.

[Trevor]

As I said before this is all crap. Why don't you go and start an argument some where else.

Harvey.

As anticipated, you again confirm, in a childish state of tantrum, that you do not have the ability, knowledge, intelligence, or intestinal fortitude, to back up any statement you have made.

The fact that you are, and have been altogether wrong, in every respect, therefore remains established beyond dispute. Proof remains recorded. There is no necessity for me to argue elsewhere.

N.B. My signature.

[icingdeath88]

Trevor's argument lies in the use of the word "progressive".
I first used the word in the thread that he started, before the QC was released, here in May 2008.
http://www.subaru-svx.net/forum/showthread.php?t=44706&page=11

When I said:

This is the same as I have stated in this thread, but as Trevor has no knowledge of the workings of the gearbox hydraulics, he could not understand what I said, so he took this word and used it in the context of his own statement, "that it was the QC circuitry that was not progressive."

This is not so. the unit turns on at about 2Volts, and stays that way till it reduces to about 1.7Volts, when it turns off. It has to be this way as the same control port is used for some other things like, low pressure for cranking the engine, and reduces the pressure for low oil temperature.

You can feel the progressive action if you do a 1st to 2nd change on half throttle, then do the same on 3/4 throttle, then again on full throttle. You will feel that the engagement pressure, or the "shift firmness" becomes progressively firmer.:)

Harvey.

I'll have to pay very close attention to this the next time I'm driving.

[b3lha]

We already had the "progressive" discussion on Budfreak's forum. Do we really have to do it here as well? Give the mods a break.:rolleyes:

A few weeks ago I posted some oscilloscope traces showing the signal that drives the A solenoid. It turns out that the solenoid doesn't work the way I thought it did. At present, I don't really understand how it works. From reading the discussion later in the thread, I do not believe that Harvey or Trevor fully understand it either. At least not in the sort of detail that I would want to understand it in order to mod it.

I was hoping to be able to tune the solenoid A maps in the TCU to get the QC effect that people seem to like. But until I understand it fully, I'm leaving it well alone. It's not worth the cost of another rebuild to figure this out by trial and error.

[Trevor]

We already had the "progressive" discussion on Budfreak's forum. Do we really have to do it here as well? Give the mods a break.:rolleyes:

A few weeks ago I posted some oscilloscope traces showing the signal that drives the A solenoid. It turns out that the solenoid doesn't work the way I thought it did. At present, I don't really understand how it works. From reading the discussion later in the thread, I do not believe that Harvey or Trevor fully understand it either. At least not in the sort of detail that I would want to understand it in order to mod it.

I was hoping to be able to tune the solenoid A maps in the TCU to get the QC effect that people seem to like. But until I understand it fully, I'm leaving it well alone. It's not worth the cost of another rebuild to figure this out by trial and error.

I am confident that I fully understand and have correctly described the pulse width modulation of solenoid "A".

However the make up of the PWM signal, which will be the result of computing various inputs remains to be finalised. Phil is the expert here and and his ongoing research, will no doubt provide this detail. This research involves a great deal of time and effort and we are lucky to have his professional services.