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kyledooley sent me this....

http://www.smallcar.com/svx/tsk.htm

Looks pretty cool and promising. It would seem to work out the issues that unplugging the resistor can cause. I'm however not sure it would work with positive manifold pressure. I'm sure you could ask them....and/or maybe modify it.

ciper....what do you think of this thing?

Its a good idea. I dont like that it works against the TCU's built in pressure adjusting, which is based on the TPS signal.

Good shift pressure while keeping the stock "ramping" pressure can be obtained with my method.

Here is how I think it works. At high vacuum the resistor has a lower value, causing soft shifts. As vacuum drops the resistor increases to the point that you are nearly unplugging the resistor.

If I was to design this Id probably use TPS voltage as a reference instead of vacuum.

This is similar to what I was planning on doing back when I had an automatic. I was gonna use throttle position to control a variable resistance in place of the dropping resistor, kind of like what ciper's guessing this is.

But it looks like this is simpler -- just a vacuum-actuated switch that's either on or off depending on manifold pressure.

I agree it would be weirder on turbos which was why I was just gonna use the TPS signal and some electronics.

I spoke with Brian at smallcar yesterday. He says the pressure switch they are using won't do positive pressure, but a different switch that has a range covering 2-3-4 psi would probably do the trick.

Personally, I think boost/vacuum is a better indication of true load than the tps, but we'd all be splitting hairs.

Brian was very interested in doing one of thes for the turbo. He actually had never thought of that angle.

He was going to be ordering a new batch of switches next week and if I wanted one for positive pressure, he said he'd be glad to look into one for me with his supplier.

I haven't e-mailed him yet, so if anyone is interested in one of these, why don't you pm me and I'll get a list together. If we get 1/2 a dozen or more turbo people, I can maybe persuade him to order and keep a small quantity.


Kyle

Well, I traded e-mails with Brian at smallcar.com today. He said he's ordered 10 1-4psi pressure switches for use with turbo cars. I'm going to be the guinea pig for this one, so I'll let everyone know how it goes when I get it in and drive around a bit.

Kyle

It just so happens that things have changed in the last few weeks and I've sold my car.

If anyone wants to give this a try, please give Brian at small car a call.


Kyle