Increased shift pressure without the CTL, sort of a repost

ciper · Post by **ciper** » Thu Nov 14, 2002 3:35 am

I had posted many times on the I-club and other sites about improving transmission performance using a higher rating resistor in the dropping curcuit.

Either people didnt understand or they just dont care, Im not sure.

Anyways since all of you are a little closer than the general Subaru public I thought Id tell you about it.

In short I increased the value of the resistor in order to provide a lower than normal voltage on the pressure bypass in the transmission.

The great part about this is that the TPS based voltage that controls shift firmness still functions correctly! The only difference being is that the map is shifted upwards. You still get "Soft" shifts at low rpm and "Firm" shifts at high but the firmness at the lowest setting (just after the tps detects non idle) is increased and it is a smooth curve until you reach about 90% throttle.

The problem with this mod is that you need AT LEAST a 25 watt resistor. If you dont want the thing getting really hot I suggest 50. Such high rated resistors are sometimes very expensive. I experimented with all different ratings. The stock is 10 at the connector which becomes about 12 once all the wiring is counted. I wouldnt go over 17 or the shifts will be too firm and much higher could cause the CTL.

I have been running my transmission like this for quite a while.

For those of you who think unplugging it is the best option you are wrong. Think of it this way, every time you come to your car in the moring you rev the engine to say 1500 rpm then put the selector in drive. It creates shock throughout the whole drivetrain.

Ill go double check but Im fairly sure my resistor is +-1% at 15 with 25 watt and its wire wrapped in an aluminum finned case.

I went to the junk yard and took the resistor from another legacy so i could use the little metal housing and connector (in case my experiment failed). It looks 100% stock.

Post by **Legacy777** » Thu Nov 14, 2002 3:57 pm

So you are using a 15 ohm power resistor instead of the stock one.....which was about 7.5 ohms I believe.

I can tell ya....from first hand experience.....my tranny is not the same after leaving the resistor unplugged......It does some weird stuff when I drive around and leave it in the 3 position.

Just to clarify.....you're running a 15 ohm 25 watt power resistor. But you're recommending a 50 watt one, which may be better to resist the heat that is generated....

I'll have to check out digikey or newark electronics....if they're still open......

ciper · Post by **ciper** » Thu Nov 14, 2002 7:51 pm

Yeah (to everything you said)

The stock resistor is rated at 10 though. What happens is that all the time the bypass curcuit has a voltage just about 0.8 volts. I dont have my notes with me so Im going to guess on the following values.

At idle the curcuit sees 1.8 volts. As throttle position increases the voltage slowly drops. At 90%+ throttle the TPS signal is basically negated and you get the .8 volts I mentioned.

I really like it, and I found a resistor for 1.5 plus 2.5 shipping so it was the BEST bang for the buck I have ever had!

Post by **Legacy777** » Thu Nov 14, 2002 10:17 pm

Where'd you find the resistor?

ciper · Post by **ciper** » Thu Nov 14, 2002 11:34 pm

WOW, I just found the price is only 69 cents!

Goto this page http://bgm.bgmicro.com/ and search for the keyword RES1078

With shipping it will probably cost you 2.50 . They accept credit cards and paypal! They have tons in stock and they are brand new!

Post by **Legacy777** » Fri Nov 15, 2002 2:31 am

cool.....pretty cheap

IggDawg · Post by **IggDawg** » Fri Dec 20, 2002 2:14 pm

So this makes the tranny shift faster/harder? sounds like a worthwhile mod. Sorry if I missed something, but are there specific instructions on this?

Post by **Legacy777** » Fri Dec 20, 2002 2:45 pm

What this does is increase the line pressure that is used during shifts.

Less line pressure equals soft shifts. More line pressure equals hard shifts....which "usually" mean quicker shifts.

I'm going to personally recommend you just not bother messing with this. I had unplugged the drop down resistor for not too long in my car......and have resulted in some rather weird/finiky issues with 3rd gear not really wanting to engage properly......and it's starting with 2nd.

It could just be age of the tranny......but I didn't have the problem before I unplugged the bastard.

Now unplugging and running an additional resistor to increase line pressure slightly are two different things. But unless you really know what you're doing.......I'd just leave it alone.....what you gain, vs. what you potentially have to loose (or gain in problems) is not worth screwin around with.

Check out some of the maxima links within this thread http://pub1.ezboard.com/fultimatesubaru ... D=51.topic

IggDawg · Post by **IggDawg** » Fri Dec 20, 2002 3:07 pm

Thanks for the warning. I'll certainly take that under consideration. I'm still elated with this new car, and it's going to be a while before I feel teh need to mod the tranny. It already shifts gobs harder than the Impreza because of the added torque. I get pinned to my seat during shifts instead of the industry standard "smooth" (see also: lame) shifts in the Impreza.

I'll certainly read up on it before I go doing anything with it.

vrg3 · Post by **vrg3** » Fri Dec 20, 2002 4:05 pm

An option other than finding a 50-watt 15 ohm resistor would be to get multiple lower-power resistors.

It'd get impractical when you end up soldering a hundred 1/2-watt 1.5-kilohm resistors in parallel, but...

A pair of 30-ohm 25-watt resistors would be decent.

IggDawg · Post by **IggDawg** » Sun Jul 25, 2004 2:23 pm

BACK FROM THE DEAD!!

I was randomly google searching my name for a thread in nabsico OT when I came across this old thread. I have a good bit of info that might come in handy. www.smallcar.com puts out a shift kit for the SVX that's basically a pressure operated switch which cuts the resistor in question out of the circuit. It's adjustable, but generally under heavy vacuum it leaves the switch inline for easier shifts, and under less vacuum (or pressure I suppose

) it cuts out the resistor for firmer shifts. This would allow for those nice comfy sloppy shifts when putting her in D or R in the morning, but still give you nice hard shifts when you drop it down to pass someone.

I have one in my SVX and I love it. I wish I'd known about this when I had my legacy turbo. I figure it'd work just fine for hte EJ22t since it's lunder a litghter vacuum that it switches the resistor out of the circuit. pressure would have hte same effect. anyone else ever hear of this dealie? I know some of my SVX bretheren are on here.

eastbaysubaru · Post by **eastbaysubaru** » Sun Jul 25, 2004 4:44 pm

It's truly too bad Ciper's not around any more. I'm sure he'd have TONS to say on this subject.

-Brian

sullione · Post by **sullione** » Sun Jul 25, 2004 6:44 pm

Whatever happened to Ciper anyway?

THAWA · Post by **THAWA** » Sun Jul 25, 2004 8:37 pm

personal issues.

sullione · Post by **sullione** » Sun Jul 25, 2004 9:38 pm

That's too bad. Does anyone still have any contact with him, just to make sure he's doing ok?

eastbaysubaru · Post by **eastbaysubaru** » Mon Jul 26, 2004 5:51 am

I've talked to him on occasion, but not really on a personal level. We're still trying to get a group buy finished up on some AWIC's with him.

-Brian

Bosco · Post by **Bosco** » Mon Jul 26, 2004 5:29 pm

I was wondering wht happened to him too...

He offered an interesting objective viepoint. Every forum has or needs a person like that... Someone to go against the grain, and keep everyone on thier toes. He seemed to be a wealth of infromation.

And he made me feel good about having a 4eat

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Increased shift pressure without the CTL, sort of a repost

Increased shift pressure without the CTL, sort of a repost