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Discussion Starter #1 (Edited)
I am at a crossroads at the moment:


(This is a Soarer btw, but differences are minimal for this debate/process)

Retain and build the cars auto box, inc raised stall.

OR

Go to the 6sp box.




Now, the auto I LOVE. It shifts so so fast (Gtech logs really put this into perspective), and even the low stall matches the stock (ceramic) turbos brilliantly, keeping the car responsive to your foot regardless of all else.

You can control the box just fine (and 2nd is GREAT for the twisties, perfect pull 30-90mph).

It matches the car, me, is brilliant in a straight line and in corners too, making for a surprisingly good track car in fact.

For a stock for BPU car I would not change it for the world. Traffic to tracks, dragstrips to cruising, all done PERFECTLY.



BUT, how is the going to change with a bigger turbo (T67dbb on a 2.5l) and the AEM (mapping box??!) + raised stall.

My understanding is that I will improve upon the shifting speed, and the raised stall (3600 I plan) will keep the car not far from lag-less to all intents and purposes.

BUT with a raised stall, it will be a PITA in traffic, and more importantly, it will no longer be suitable for tracks (only drag strips, which are not really my thing).

Am I right with this thinking? Anyone track a single-turbo built auto?


Or is a 6sp better suited to my needs? I always feel manuals put the power to the ground in a much less tractable way, less smooth, slower + more brutal shifts, hence why I am loathe to go this route if happily avoidable.


Thanks
 

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We have a fully built APU auto with a BL trans and a 3800 stall. It's extremely responsive with our Innovative DBB76mm strapped on. I would defintly go with bb on an auto with a big turbo and not a regular cartridge. You don't notice the increased stall. The turbo spools quicker and eliminates the lag.
 

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Discussion Starter #3
What you ever raod raced your car?

As ANYONE with a built auto ever road raced it?
 

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First, I have not driven a built auto, but I am in the same boat as you. I have grown to live the auto, but its not without imperfections. Pretty soon my tranny may die, and then I have to make the decision.....3.xgrand, or 7k +. I would rather have the manual for these reasons:

1) With the correct clutch, its one if the strongest OE manuals in the world.
2) It's one more thing that DOES NOT have to be significantly upgraded with the addition of more power.
3) You can buy a carbon clutch (tilton or c/c) and be done with it....litteraly
4) NO MORE POWER SURGES AND LURCHING FROM AIR CONDITIONER WHILE STOPPED AT A LIGHT/SIGN !!!!!!!! :)
5) With 6-gears, the mileage is better, and it is much easier to keep the car in your favorite part of the powerband for the twisties.

This is comming from someone that does 5-10 nintey mile trips through the twisties for every one highway pull.


The built auto will do pretty well on the track. Higher stall will creat more heat (especialy for daily driving) and will need additional coolers. Also, some companys suggest that you shift manualy with their built auto, while others do not.....just something to think about.

All in all, the auto is awesome for up to 400 rwhp, and can be reliable for more before it needs to be built, but in the end the manual is better suited for the twisties, and if you ever went to a pretty high power level you would have to ditch the toyota auto for a TH400 or 350 anyway.

Hope this helps some.
 

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Discussion Starter #5
Cheers for that, you definately seem to be in a similar position, much appreciated.

I would like to press further on one point: The manual being better for twisties: For anything short of 10/10th by a pro driver, I disagree. The combination of instant shifting and the lag-killing capabilities of an auto more than make up for the lack of 2 ratios. A auto is always in the powerband due to the torque convertor slip, with a manual, being caught out of the powerband is much easier.


While on the point, do any of the built 4-sp Supra boxes come/can be specced with a manual valvebody?

How EXACTLY does a manual valvebody work? Can you use it just like a fully sequential manual/paddle shift minus the paddles?
 

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The manual vs auto performance in the twisties is more of a preferance thing, but I will agree that a good auto is faster in the 1/4.

Straight out of the box you can shift the AEwhatever auto tranny manualy, maybe it was different in europe, but there is a button that says 'manu' on the passenders side of the gear selector plate, when its pressed a light with the same text somes on in the dash. This turns off automatic shifting. You can shift 1-3 with the shifter, but must use the 'manu' button to engage 4th overdrive, which is not selectable with the shifter.

I remember some post about aftermarket paddles that could somehow be controlled through the AEM, not sure what happened to it, but it seems like alot more trouble than its worth.

If you decide to test out manual shifting, i suggest not letting off the gas, which is the obvious way that most people do it. Back when I wished I had a manual I learned how to let off the gas while shifting as in a real manual pretty well, it worked great, but probably has some negative effects on the tranny. If you need to be doing something active with the auto tranny, work the overdrive, helps alot to keep it out of that top gear.
 

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Having owned a BPU 6spd and now own a BPU auto I know exactly what you mean. For most of the canyon roads the 6spd car always seemed stucked between 2nd and 3rd. To get the response I wanted I had to be in 2nd but I was very close to the redline and I needed to upshift anytime I hit a straight. Yet if I just kept it in 3rd I was too low in the powerband to steer the car with the throttle this had to be saved for high speed sweepers and straightaways. Annoyingly there is constant shifting between 2 and 3 if you really want to drive the car fast. With the Z06 I had the low end torque to just leave it in 3rd and that was perfect but with the Supra there simply isn't enough meat in that part of the power band. With the auto tho the taller 2nd gear is really in the sweet spot of canyon driving. You have plenty of response to drive the car with the throttle and there is enough revs left to accelerate through most straights without an upshift. It's so hard to say which was faster between the BPU 6spd and the BPU Auto but if I had to put my money on it I would bet on the auto for the sole fact you could concentrate more on your line and the driving and worrying less about hitting the rev limiter and shifting. I would think with a built auto and a high stall you would need tons of cooling to road race the car in any kind of heat and even then you would probably want to do a few hot laps and then a cool down lap during your run session to reduce any excess heat. Tranny oil temp sensor would probably be very usefull here in keeping things alive.
 

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A high stall torque converter would not lend itself well to road racing due to the amount of heat that will build up from the torque converter constantly slipping. I would imagine that would want to leave the factory torque converter in the car with a couple of coolers to keep the heat down.

Steve
 

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We run the biggest B&M cooler with a 3800 stall. On the highway the temps don't even register at the lowest temp readout on our gauge wich is 100 degrees. In town we can get up to ~135 wich is nothing.
 

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Discussion Starter #11
Kal,

You hit the nail on the head with regards to the whole 2nd/3rd gear thing it is exactly why I prefer an auto = It makes far better use of the ratios, the TC ensuring the power is always there.


I am now leaning towards building my Soarer auto + adding that product on the link above. This + a raised stall speed + 2-3 tranny coolers should provide an excellent, if extremely unorthadox, road race and street setup.

Any further comments most welcome.
 

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Discussion Starter #13
Thanks StSupDog, have PM'ed him.
 

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Discussion Starter #15
Hey Phil, don't see you post over here much.

I am going with that box from latent solutions, so I can do all the shifting myself + built A340E with 3200rpm stall.

I would be VERY interested in how you get on with that setup, as it may well be part of 'stage 2'. Give me a shout when you have got yours in, would be nice to get a ride in it. You are brave being the 1st TH400 Supra in the UK. I decided I am being the 1st on enough things to experiment too much with this too, at least at first.
 
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