Small Car Kit...

[michael]

Originally Posted by dromano

Matt,
Did you notice a reduction in tranny temps after installing the shift kit? I could use a heat reduction here in the desert, when its hot (100+) I run 100 degrees over ambient. It's no fun watching the temp gauge go over 200 degrees. TIA
Dave

If you have a trans cooler, is it in front of the a/c condensor? Do you roll commando! With no splash guard There have been reports that things stay cooler without it.

[Trevor]

DUTY SOLENOID VALVE "A".

This is a pulse width modulated duty solenoid valve, ( Sometimes known as a pulsoid). The device is incorporated in the SVX transmission control system in order to adjust line pressure in the following manner :-

The fluid line is provided with a bleed or bypass via an on/off device, in the form of an electrically operated valve. This solenoid valve is opened and closed repeatedly, in a rhythmical manner by a control current which is turned on and off by the transmission control unit (TCU) at a very fast rate. The valve is a normally closed device, and remains closed in the event of the loss off a control current.

After passing through this modulated solenoid valve, the continually interrupted pressure is in the form of a pulsed flow. When the peaks level off with the troughs, there is a resulting overall steady reduced pressure. The level of this pressure is adjusted by varying the on/off intervals. Most often the length of the on time is adjusted and the number of on/off pulses per second is kept constant. The usual rate is around 50 cycles per second.

The resulting adjusted output pressure is therefore delivered as a rapidly fluctuating stream. The system incorporates an expansion chamber as a smoothing element, which works as a sort of cushion. This device is usually in the form of a cylinder and piston or diaphragm, backed by a coil spring. In the SVX system the component is described as a Pressure Modifier Accumulator. The high pressure peaks in the stream press the piston outwards and become rounded off, while the low pressure troughs are filled in as a result of the piston moving inwards under spring pressure. The end result is a smoother level of pressure, such that controlled devices are not materially affected.

An increase in the volume of fluid controlled, is achieved by transferring the solenoid regulated pressure, to a pressure modifier valve and a regulator valve.

It should be clear that by “chopping” the fluid supply in an adjustable way, pressure control is achieved economically using a simple poppet type solenoid valve, with few mechanical or electrical complications. However the valve remains in a continuos cycling mode, which imposes rather arduous mechanical stresses.

THE DROPPING RESISTOR CIRCUIT.

It will be immediately apparent that a sudden on off cycle tends to cause what could be called a hammering of the valve seat, even though this is largely checked by the viscosity of controlled fluid flow. The dropping resistor introduces a second series of current pulses applied in parallel with the control signal. These shorter pulses are applied during the off cycles and timed to check the travel of the armature as it reaches the closed position, thus reducing both shock and noise. These secondary parallel signals in effect, “round off” the closing period and reduce the closing shock. This arrangement can be made even more sophisticated and configured so as to soften the the opening cycle, as well as the closing of the valve.

It will be appreciated that reducing the resistance in the circuit, or opening the circuit by omitting the dropping resistor, has two outcomes. Firstly the relative electrical off time is increased thus increasing the line pressure and therefore makes shifts more abrupt. Importantly as a second issue, increased shock loads are applied to the valve.

It is a documented fact that the line pressure control solenoid is the first to fail due to having by far the most arduous duty to fulfill. Failure is usually mechanical resulting in the valve seat not closing properly and as a result line pressure is markedly reduced. The end results are drastic, especially in respect of transmission friction surfaces. The fault will not necessarily be registered as a fault code, as the armature of the valve can be in the fully closed position with the problem confined to a worn and faulty valve seat. In the event of an electrical fault, which will register, the valve being normally closed, will fail safe and result in maximum line pressure.

[dromano]

Originally Posted by michael

If you have a trans cooler, is it in front of the a/c condensor? Do you roll commando! With no splash guard There have been reports that things stay cooler without it.

I have a 30k GVW Hayden stack cooler, it's between the radiator & condensor.
I'm guessing the 'splash guard' is the under cover. There is a thread here that points out the pros & cons of the under cover being removed. I am convienced it should be on the car. Still interested in hearing if the shift kit causes the tranny temp to be lower.

[oab_au]

Originally Posted by dromano

I have a 30k GVW Hayden stack cooler, it's between the radiator & condensor.
I'm guessing the 'splash guard' is the under cover. There is a thread here that points out the pros & cons of the under cover being removed. I am convienced it should be on the car. Still interested in hearing if the shift kit causes the tranny temp to be lower.

I can't see there being any reduction in ATF temps, due to the shift kit being fitted. The under cover helps the flow of air through the coolers at the front of the car, at speed. It does not work as well at low speed city running.

I liked the set up with the ATF cooler in the wheel well, that was done by ?? somebody, It reduces the hot air flow through the other two units.

Harvey.

[Trevor]

My condensor is fitted between the radiator and condensor. I queried this with the transmission specailist who did the job, having doubts about the effectiveness. I was told that this was in all respects correct, as the object was to raise and maintain the transmission at engine temperature. He pointed out that it was not a coincidence that the original is combined with the radiator. Right or wrong I accepted this explanation as logical.

[dromano]

Originally Posted by Trevor

My condensor is fitted between the radiator and condensor. I queried this with the transmission specailist who did the job, having doubts about the effectiveness. I was told that this was in all respects correct, as the object was to raise and maintain the transmission at engine temperature. He pointed out that it was not a coincidence that the original is combined with the radiator. Right or wrong I accepted this explanation as logical.

Every thing I have read here points to installing the cooler in front of the condensor. In that position it is 100% effective, any other location reduces the cooling efficiency

[michael]

I have mine in front, no splash guard and bypassed the rad. It runs quite cool, I forget how cool as I removed my temp guage. Harvey, I think he figures if the smallcar kit firms up the shifts there will be less slippage. Less slippage=less heat.

[Trevor]

Originally Posted by michael

I have mine in front, no splash guard and bypassed the rad. It runs quite cool, I forget how cool as I removed my temp guage. Harvey, I think he figures if the smallcar kit firms up the shifts there will be less slippage. Less slippage=less heat.

But -- when the duty solenoid cries enough and the valve seat starts to leak you will lose line pressure, with no warning and there will be slippage and heat.

[michael]

I'm not condoning the kit in fact I recently removed mine after replacing the resistor. I was just pointing out his expectations.

[Trevor]

Originally Posted by michael

I'm not condoning the kit in fact I recently removed mine after replacing the resistor. I was just pointing out his expectations.

OK, no problem. Be sure I was not making any accusations.

What I say is that the kit may have its uses, but members should be aware as to exactly what is involved and use it accordingly.

[Budfreak]

Originally Posted by dromano

Every thing I have read here points to installing the cooler in front of the condensor. In that position it is 100% effective, any other location reduces the cooling efficiency

The cooler can not be installed in front of the condenser unless it's either a damn small cooler or a you do a little surgery to some things up front. I looked to put it in the front when I put mine in and it simply wasn't gonna happen.

[oab_au]

Originally Posted by michael

I have mine in front, no splash guard and bypassed the rad. It runs quite cool, I forget how cool as I removed my temp guage. Harvey, I think he figures if the smallcar kit firms up the shifts there will be less slippage. Less slippage=less heat.

I don't believe that the clutches and the band do much slipping to produce much heat on the changes. The major source of heat from the trans, is produced by the torque converter.

The long smooth changes are not caused by slipping. There are other things going on, when the change takes place, that makes it seem like there is slippage. The torque is turned down, the line pressure is reduced, the change takes place, the line pressure is turned back up and the torque is turned back up.

The shift kit just raises the throttle pressure in relation to the pedal position. In other words, the trans thinks that you foot is down harder than it really is, so it raises the line pressure, so you get a full throttle change on part throttle. If the pedal is on the floor the change is the same, regardless if the kit is fitted or not.

Harvey.

[Trevor]

Originally Posted by oab_au

I don't believe that the clutches and the band do much slipping to produce much heat on the changes. The major source of heat from the trans, is produced by the torque converter.

The long smooth changes are not caused by slipping. There are other things going on, when the change takes place, that makes it seem like there is slippage. The torque is turned down, the line pressure is reduced, the change takes place, the line pressure is turned back up and the torque is turned back up.

The shift kit just raises the throttle pressure in relation to the pedal position. In other words, the trans thinks that you foot is down harder than it really is, so it raises the line pressure, so you get a full throttle change on part throttle. If the pedal is on the floor the change is the same, regardless if the kit is fitted or not.

Harvey.

The above statement is not correct.

The reduction of the effect of the parallel resistor circuit, changes the level of the modulated signal regardless of all else. The fundamental line pressure is changed exactly in accordance with the functions I have previously detailed within this thread.

[immortal_suby]

Originally Posted by oab_au

I liked the set up with the ATF cooler in the wheel well, that was done by ?? somebody, It reduces the hot air flow through the other two units.
Harvey.

That was me!



No, I didn't see any drop in temps with the shift kit.

[immortal_suby]

Originally Posted by Budfreak

The cooler can not be installed in front of the condenser unless it's either a damn small cooler or a you do a little surgery to some things up front. I looked to put it in the front when I put mine in and it simply wasn't gonna happen.

The B&M stacked plate # 70255 fits easily in front of the condensor. I have one there on 2 svx's.