Info: Leading Cause of Transmission Failure at Elevated Power Levels.
#16
Lexus Test Driver
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Jeff I am not much of a transmission guy and I only know the basre basics. Do you think this sprag can be adapted to the A340 series 4-speed transmissions? Also, it appears that the main problem with the A340 series is tha second gear sprag rolls when shifting under high torque loads and there goes the transmission. I appreciate your comments.
Ryan
Ryan
#18
Lexus Champion
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I've rebuilt a few A340e and A341E to support high hp successfully before and one thing that I can reassure you is that no matter what you do to the intermediate sprag, the transition from going from first gear to second will cause a dramatic shock which will roll the sprag. This is why all built supra transmission builder will tell you that if you are doing a burnout, leave it in first gear and first gear only. Then once you're finished then you can shift up.
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Thanks,
Ryan
#20
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I actually managed to break the sprags once again in testing lol. They need to be revised to be stronger. They are probably strong enough for most people, but it's not on par with my requirements. When it's strong enough to withstand my driving, then it will be strong enough for everyone else
. I have my shifts in my valve body calibrated to be extremely harsh and that's probably whats snapping these sprags. It is shifting so hard on 2-3 shifts that the car lights up the tires and kicks out sideways on shifts lol ![Big Grin](https://www.clublexus.com/forums/images/smilies/biggrin.gif)
SC400TT, I can spec out the A340E size sprag if I have the sprag housing, sprag itself, and sun gear in my hand. This way I can measure it all out and spec out whatever needs to be sent to the manufacturer.
Speedaddic, sprags would be purchased from me, but R&D is not complete yet so I don't feel comfortable releasing a unfinished product for sale. Once the sprag R&D is complete, I will become a vendor here on CL so I can sell built transmission packages. All the sets I sell right now are for testing purposes, so no guarantee they won't fail. However, I am offering free sprag replacements right now for people that buy a test sprag from me if the sprag fails. I don't think anyone here bought the test sprags from me, but all of the sprags have been purchased over on My.IS.
![Smilie](https://www.clublexus.com/forums/images/smilies/smile.gif)
![Big Grin](https://www.clublexus.com/forums/images/smilies/biggrin.gif)
SC400TT, I can spec out the A340E size sprag if I have the sprag housing, sprag itself, and sun gear in my hand. This way I can measure it all out and spec out whatever needs to be sent to the manufacturer.
Speedaddic, sprags would be purchased from me, but R&D is not complete yet so I don't feel comfortable releasing a unfinished product for sale. Once the sprag R&D is complete, I will become a vendor here on CL so I can sell built transmission packages. All the sets I sell right now are for testing purposes, so no guarantee they won't fail. However, I am offering free sprag replacements right now for people that buy a test sprag from me if the sprag fails. I don't think anyone here bought the test sprags from me, but all of the sprags have been purchased over on My.IS.
#21
Lexus Champion
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Great to see the IS crew is supporting this.. so, the sprag is the only major component a person needs if he's trying to do 400whp reliably (not your level
) ? ...well, including an extra tranny cooler.
if it's more, then we can leave it at that![Smilie](https://www.clublexus.com/forums/images/smilies/smile.gif)
come to the realm of the v8's...it's just two more cylinders and you won't have to boost too much
![Smilie](https://www.clublexus.com/forums/images/smilies/smile.gif)
if it's more, then we can leave it at that
![Smilie](https://www.clublexus.com/forums/images/smilies/smile.gif)
come to the realm of the v8's...it's just two more cylinders and you won't have to boost too much
![Smilie](https://www.clublexus.com/forums/images/smilies/smile.gif)
Last edited by sam430; 07-15-10 at 11:16 AM. Reason: what happened to all the OG? we need them to answer difficult questions...a tleast difficult to me :)
#23
Driver
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are any of the AEM EMS users on here using the aem to control the transmission at all??? I have swapped my car over to a A340 and with the AEM controlling the transmission, I have been more or less having the EMS granny shift it for me (pulling timing ect... between shifts). Just wondering if in addition to the sprag, possibly we may be looking at more of a control issue with the transmissions. like jeff is saying, he feels the added snap of the valve body upgrade could be the culprit, so just wondering what your exact tranny setup is on your car jeff.
#24
Lexus Champion
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ownzu:
I am planning more or less the same thing with my PCS stand alone for my A340. I will keep you all posted with how it works.
Ryan
I am planning more or less the same thing with my PCS stand alone for my A340. I will keep you all posted with how it works.
Ryan
are any of the AEM EMS users on here using the aem to control the transmission at all??? I have swapped my car over to a A340 and with the AEM controlling the transmission, I have been more or less having the EMS granny shift it for me (pulling timing ect... between shifts). Just wondering if in addition to the sprag, possibly we may be looking at more of a control issue with the transmissions. like jeff is saying, he feels the added snap of the valve body upgrade could be the culprit, so just wondering what your exact tranny setup is on your car jeff.
#25
Lexus Test Driver
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I actually managed to break the sprags once again in testing lol. They need to be revised to be stronger. They are probably strong enough for most people, but it's not on par with my requirements. When it's strong enough to withstand my driving, then it will be strong enough for everyone else
. I have my shifts in my valve body calibrated to be extremely harsh and that's probably whats snapping these sprags. It is shifting so hard on 2-3 shifts that the car lights up the tires and kicks out sideways on shifts lol ![Big Grin](https://www.clublexus.com/forums/images/smilies/biggrin.gif)
SC400TT, I can spec out the A340E size sprag if I have the sprag housing, sprag itself, and sun gear in my hand. This way I can measure it all out and spec out whatever needs to be sent to the manufacturer.
![Smilie](https://www.clublexus.com/forums/images/smilies/smile.gif)
![Big Grin](https://www.clublexus.com/forums/images/smilies/biggrin.gif)
SC400TT, I can spec out the A340E size sprag if I have the sprag housing, sprag itself, and sun gear in my hand. This way I can measure it all out and spec out whatever needs to be sent to the manufacturer.
#26
Lexus Champion
iTrader: (10)
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are any of the AEM EMS users on here using the aem to control the transmission at all??? I have swapped my car over to a A340 and with the AEM controlling the transmission, I have been more or less having the EMS granny shift it for me (pulling timing ect... between shifts). Just wondering if in addition to the sprag, possibly we may be looking at more of a control issue with the transmissions. like jeff is saying, he feels the added snap of the valve body upgrade could be the culprit, so just wondering what your exact tranny setup is on your car jeff.
#28
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#29
Lexus Champion
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Hate to see this effort die. Any updates? What do you think is the power/torque capacity of a stock A650e and also one built with the stronger sprags? Stock I am guessing in the 350rwhp/rwtq range.
The stock ECU pulls timing for shifts so maybe that would give some cushion here. Aftermarket tuning options to reduce the shock during shifts may also further the cause as noted by others above.
The stock ECU pulls timing for shifts so maybe that would give some cushion here. Aftermarket tuning options to reduce the shock during shifts may also further the cause as noted by others above.
#30
Intermediate
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Great to see some one doing all this development work... I used to do this kind of stuff when i was building and racing motorbikes. We used to get clutch baskets made from solid billet and specially made and hardened gears and selectors so i appreciate what your going thru....... Now having said that, if ever i get my baby supercharged i know who to contact about transmission upgrades...