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Auto Trans Shift Kit, cooler, ECT/PWR switch and line pressure |
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Auto Trans Shift Kit, cooler, ECT/PWR switch and line pressure |
by Peter Scott
The Soarer auto transmission is a typical Lexus luxury item - very smooth. The ECU retards the engine timing during a shift so that there is less torque going through the trans as is glides between shifts - you can hardly feel them.
The disadvantage for performance driving is that the change is quite slow - especially the 1st to 2nd change when under full power. The trans slurs from gear to gear. For a hotted up twin turbo the engine can pop while waiting for the trans to change as the engine winds back the timing during the change. No problems in the V8 like this but the change is still slow and time is lost during the change.
Not so with a shift kit.
A shift kit is a modified valve body that lives inside the transmission. It is an hydraulic item that makes the transmission shift much quicker and as a result the engine timing is not retarded nearly as long. Rather than slurring through gears smoothly, the shift kit changes hard and fast. Even on my V8 the change is now hard enough to chirp the wheels or send the back of the car sideways momentarily during a change. Now during a change the car leaps forward, not sagging back.
Now that all sounds very aggressive, but for normal driving the trans is still acceptably smooth - the harshness of the shifts can be tuned somewhat by changing the line pressure - a simple cable adjustment.
If you have never thought your transmission changed too slow then don't sweat a shift kit. If you want a sportier change, a more dynamic driving experience then perhaps a shift kit is for you.
I got mine from MV Automatics (only $385 fitted! - available as complete valve body change over with DIY instructions too) also got myself a trans cooler - no more slurring between gear changes - trans changes very quick. If you want to fit it yourself and keep your old valve body then that is also available.
MV Automatics:
Michael Vidau (Soarer guru)
1 Stirling Road
Blackwood 5051
South Australia
ph 08 8370 0430
fax 08 8370 0431
Live in another country? http://www.timeanddate.com/worldclock/city.html?n=5 is a good place to start - how to dial Australia - the time difference explained.
Michael doesn't have email or an internet site.
Michael at MV Automatics rang me - he has done so many shift
kits that he has completely run out of change over bodies - everyone just gets the shift
kit with no change over, then I imagine the old valve body sits on a garage shelf or worse
in the bin!
(Because I just live up the road from him, I just drove in and had my valve body
modified).
He has rang all the importers and he can't get stock. So if you have a shift kit fitted
then please send the old valve body back. He will give you $50 for it. Now that he has run
out, it means if you want a shift kit you will have to send him your valve body first then
wait for it to come back - so the car will be off the road for longer.
He has only run out for one reason - planetsoarer readers have been buying them! So if you
have a valve body at home doing nothing please send it back so that others don't have to
keep the car off the road for so long.
You get $50 and some other reader can keep down time to a minimum.
I had a stage 1 shift kit fitted, new solenoids (my
transmission was changine from 1st to 3rd sometimes, and then it was playing up with o/d
and not changing properly - Michael changed the solenoids and now it is terrific) and a
trans cooler fitted (getting ready for supercharger in couple of months).
When I'm in the mood I love it - shifts fast and hard instead of smoothly slurring into
the next gear - faster for sure, measurable difference in acceleration times. The TRC
(traction) warning light flashes every change if turned on - if TRC is off then it's chirp
the wheels time!
Now that I have changed the line pressure the trans is still smooth enough for driving
around town daily.
http://planetsoarer.com/sounds/v8shiftkitchirp.mp3
The above is very small 106 kb sound file - hear wheels chirp 1st to 2nd gear. Cruising
with the ECT switch to Norm the change is quite ok - you can feel it - but other drivers
who have tried my car and passengers reckon it's ok. Drive quick though and it is really
noticeable.
There is a longer MP3 file of my car going around a race track
(The mp3 file (1.3 MB) http://planetsoarer.com/sounds/Mallalalap2.mp3
) - this also shows the trans shifting quickly (and me oversteering too much!)
Simon Triantafillou took some pics when he installed his: Shift Kit Installation
Lam Tran installed one as well - see here.
March last year I was reading AutoSpeed as usual and came across Julian Edgar's article on Tweaking the Shift:
| Tweaking the Shift Technical Features - 05 March 2002 Despite the movement over the years in automatic transmission technologies from fully hydraulic to hybrid electronic-hydraulic to fully electronic, the control systems have used basically the same operating logic. And that makes this little modification tweak something that can be potentially applied to a very wide range of autos. On the guinea pig 1991 Lexus LS400, the modific...
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The above article, like many in his book 21st Century Performance, apply directly to the 1UZ-FE Toyota V8.
quoting Julian Edgar from article: "But surely that would result in a lot of
negatives - like won't the engine now bump the rev limiter before changing? And won't all
the shifts be harsh? And what about when flicking the Power/Economy mode switch - that
must do something bad.
Well, on the Lexus the answers are no, no, and no.
The improvement in transmission behaviour is major. It changes more crisply. It better
uses the (sweet) rev range of the 4-litre V8. When climbing hills or wanting better
in-gear acceleration, it drops back a ratio more readily"
In the above photo of my engine I have loosened the cable right off. Before the shift kit I had tightened it up - that is I had loosened the nut on the cable on the throttle side (this side) and tightened up the nut on the other side. But with the shift kit the transmission was shifting too hard - I ran Michael and straight away he said to loosen off the cable.
The difference was startling. Now when I drive around normally you can't really tell there is a shift kit. When I boot it it still changes hard and fast. So know I do have best of both worlds - nice and smooth for around town, chirping the wheels when having a drag.
A couple of people have now measured the oil temp of the Soarer transmission while driving. Sure enough it gets very hot, too hot when doing track work. Oil that gets too hot for too long shortens oil life and transmission life.
Again I went back to Michael and he fitted a transmission cooler:
The cooler with the copper coloured end tanks is the trans cooler. A very good budget upgrade - only around $150 fitted from memory. No more trans heat problems now. Looks like I have already got a few dents in it here in this photo. The long black cooler below it is the standard power steering cooler for the UZZ32 Active Soarer. The UZZ32 is the only Soarer to have this type of cooler. Also in the photo is my big horn - fitted in Japan - it's one of 2 - fairly loud. Top of the photo below the aluminium bumper is the custom air intake for the BFI.
So a cooler is recommended. For the V8 Type IV Toyota fluid is recommended - for the 6 cylinder cars Dexron fluid is ok
AutoSpeed also have a good article on Cooling the Trans:
| Cooling the Trans Technical Features - 01 October 2003 Heat kills transmissions - as a rule of thumb, every 6 degrees C above 100 degrees C temp cuts the life of the transmission fluid in half. And it's not just the trans fluid that suffers, either. Any auto trans rebuilder will tell you that by far the majority of auto trans failures can be related to overheating. So a transmission oil cooler is A Good Thing - albeit expens... |
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On my car the ECT switch does 3 things. It makes the suspension firmer - noticeably so. This may only be a UZZ32 Active suspension thing.
Another thing the switch does is make the trans change down more readily and hold gears longer. I haven't notice much difference between PWR and NORM when the foot is flat to the floor. The biggest difference is normal driving. With the switch on the NORM position the transmission will select a higher gear and change up sooner. In PWR the trans will stay in a lower gear longer and change down a gear rather than lug along in a higher gear.
Finally it affects the quality of the change. In PWR mode the trans changes a bit quicker and a bit harder compared to NORM mode. This was especially noticeable with the line pressure high and shift kit installed.