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I'm going single turbo!!!


Jamesy

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I know for a fact that the stock ecu pulls back the timing and closes the trac butterfly slightly to reduce the levels of torque going through the box. This is done for a reason and was done with the stock levels of torque in mind. When you add a single turbo into the equalation which adds around 150ftlb more torque its only a matter of time before the sprag gear breaks on the box. You just said it your self above.... was fine on the hybrids and went single and look what happened.

 

If you want big power on a auto then TH400 or Powerglide..

 

Go on the AEM forum and type in Auto and well as auto and retard on supraforums!

 

Ryan

 

I would be frightened to type in retard on an american forum!!!

So toyota pull timing to save the box at stock 0.8 bar hp and torque, then we add half that again and it still lives even though the small difference in timing pulled still leaves it way above stock!!! do the math the timing is pulled for smoother shifts to make the car drive nicer not to save a box that can live with an extra 150 hp and god knows what torque increase, the argument defeats itself as we are talking about tuned cars that put out way more than stock, it is done for refinement!!!!

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I would be frightened to type in retard on an american forum!!!

So toyota pull timing to save the box at stock 0.8 bar hp and torque, then we add half that again and it still lives even though the small difference in timing pulled still leaves it way above stock!!! do the math the timing is pulled for smoother shifts to make the car drive nicer not to save a box that can live with an extra 150 hp and god knows what torque increase, the argument defeats itself as we are talking about tuned cars that put out way more than stock, it is done for refinement!!!!

 

Although I can see your point I will have to disagree, you're looking at it wrong. The retard is there to alleviate slippage/snatch on the clutch packs and gearing when shifting. In much the same way you lift off in a manual. Yes, your'e going to bring up the fact that you can flat shift a Getrag and they are ok, except this too shortens the life expectancy of the box eventually if ignition cut isn't used ( ahem shift retard ;-)). The auto is weaker, fact, no need to dingle round it. The shift retard is not there to limit power going though the box but to give the box time to swap ratios with as little slippage/snatch as possible, which also helps to keep the heat down. It isn't the fastest way to shift, but it helps the box live, specially the 2nd gear sprag.

Edited by Miguel (see edit history)
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I would be frightened to type in retard on an american forum!!!

So toyota pull timing to save the box at stock 0.8 bar hp and torque, then we add half that again and it still lives even though the small difference in timing pulled still leaves it way above stock!!! do the math the timing is pulled for smoother shifts to make the car drive nicer not to save a box that can live with an extra 150 hp and god knows what torque increase, the argument defeats itself as we are talking about tuned cars that put out way more than stock, it is done for refinement!!!!

 

Get a Standard auto on your dyno as see what the torque level is when it changes gear and then put on a single turbo auto which has the stock ecu (with trac enabled) in place with say an EMU or AEM and see what torque levels it puts out. You will find they are almost identical.

 

I have looked into all this more than you think!

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Although I can see your point I will have to disagree, you're looking at it wrong. The retard is there to alleviate slippage/snatch on the clutch packs and gearing when shifting. In much the same way you lift off in a manual. Yes, your'e going to bring up the fact that you can flat shift a Getrag and they are ok, except this too shortens the life expectancy of the box eventually if ignition cut isn't used ( ahem shift retard ;-)). The auto is weaker, fact, no need to dingle round it. The shift retard is not there to limit power going though the box but to give the box time to swap ratios with as little slippage/snatch as possible, which also helps to keep the heat down. It isn't the fastest way to shift, but it helps the box live, specially the 2nd gear sprag.

 

The other way of looking at it would be that if 'bangs' into gear there is less slipage and therfore heat and the clutch packs wikll last longer, how much less torque is the pulled timing resulting in for a split second??? We will prob have to agree to dissagree on this one but the guy I use for transmissions who builds boxes for 2000hp cars is the one who informed me of his views if you want a strong 4 speed auto you will need to go yank. As like you say Mig the 2nd gear sprag is very weak.

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The other way of looking at it would be that if 'bangs' into gear there is less slipage and therfore heat and the clutch packs wikll last longer, how much less torque is the pulled timing resulting in for a split second?? We will prob have to agree to dissagree on this one but the guy I use for transmissions who builds boxes for 2000hp cars is the one who informed me of his views if you want a strong 4 speed auto you will need to go yank. As like you say Mig the 2nd gear sprag is very weak.

 

I think we'll have to. In a perfect world were clutches never disengage, that would be the case. You of all people should know how much 6 degrees of timing pulled can drop power. I don't think anyone is disagreeing with your transmission guy that if you want big power you need to go with a yank box, pity about the massive transmission losses that come with them.

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I think we'll have to. In a perfect world were clutches never disengage, that would be the case. You of all people should know how much 6 degrees of timing pulled can drop power. I don't think anyone is disagreeing with your transmission guy that if you want big power you need to go with a yank box, pity about the massive transmission losses that come with them.

 

that sprag looks interesting though

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Guest SupraGTE
that sprag looks interesting though

 

take the time to look the other parts they sell :) the conversion kit and "flywheel" for 4l80e boxes , did see a few threads in Us that they installed and very good kit , and exellent service

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Now ive decided to buy the BL box i feel much happier about it all. The fact Michel Lane has built it is a bonus!!

 

Got the 3800 hi stall too but prob wontb use it for now.

 

Well at least that way if you don't like the way it drives you can swap in the higher stall. :)

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The GT35R should be making positive boost at just over 2000rpm so think you'll be better without it.

 

Yeah thats what Lee and I discussed earlier. Maybe a 3200 would be good but for now will try without one!

 

I reckon it would be a nice drive too.

 

Without one yeah?

 

 

Well at least that way if you don't like the way it drives you can swap in the higher stall. :)

 

exactly!! :thumbs:

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