"buzzing" an engine with auto gearbox - experts??

[1JZ-Rolla]

So... tonight my car suffered an unfortunate "incident" when its driver shifted down into 1st gear, instead of up into 3rd whilst at WOT, buzzing the engine for a moment before I frantically smashed the B&M ratchet shifter from the passenger seat back the other way

The question is, since conrods/gearbox etc aren't left behind on the road, and the car appears to drive normally, what would have actually been the sequence of events (and possible damage) to gearbox internals?

Some background, the motor is a 1JZ, with A340 auto, running 2800rpm stall converter & stage 1.5 shift kit (valve body mods). There is no ECU intervention for the shift, so all gears are selected manually via the B&M ratchet, it will do whatever the driver tells it to do (hence why its rare for anybody other than me to pilot it!).

The gearbox was shifted from 2nd to 1st at 7000rpm, what i'm surprised about is that the RPM recall only showed 7600rpm after the shift, I would have expected it to go higher. The ECU was trying to pull the revs back down at for that moment (could hear the rev cut popping), but you'd think would have no chance of being effective against the wheels trying to push it higher.

My understanding of the internals of an auto box are limited, but what can I expect would be the result of such an event, and what stopped it from buzzing the engine to more like 9000rpm?


Cheers

[oldcorollas]

the convertor allows the wheels to spin faster than engine?
if it auto locks up in every gear, then can overspin easily, but doesn7t the convertor slip a bit when not under power?

[1JZ-Rolla]

no lockup in this instance so may be the saving grace... I figured that since there's strong engine braking in 1st gear that it would be almost like being locked though, doesn't the stator play a part in not allowing the wheels to overrrun the engine? Or am I getting my auto box components mixed up (quite likely )

[oldcorollas]

(i dunno )

[fixeruperer]

^haha

the wheels probably just locked up instead of shit breaking, have you dumped the oil and checked it for metal ?

[The Real Roadrunner]

what tacho? it may have only recalled 7600 due to the ecu cutting all power/spark above this point.

Don't let other ppl drive your car, easiest way not to have problems.

[1JZ-Rolla]

what tacho? it may have only recalled 7600 due to the ecu cutting all power/spark above this point.

LogMax RPM Screen in Microleb ECU. Revcut is set at 7440rpm from memory

Don't let other ppl drive your car, easiest way not to have problems.

Thanks dude, hindsight is a bitch like that hey. Was trying to help out a mate in converting from FWD to RWD goodness with his new dragcar plans.... Maybe should have just scoured the saturday classifieds for one of the many private sales of VL turdbro choofness and gone for a test drive instead

[The Real Roadrunner]

logging in the microwreck probly wouldn't have chased the cas quickly enough. but seeing its auto it probly wouldn't go much higher than 8500 worst case 9K which it should cope with provided its not sustained or common.

sounds like your trying to convert a ghey into a straight, good luck with that maybe start with an early POS celica and leave the corollas for the men

[1JZ-Rolla]

yep, definitely a case of trying to drag a homo off his float at mardi-gras


I reacted pretty damn quick to hit the shifter back the other way when it happened, lets hope I was quick enough!

How many spare JZ's do you have around the workshop Linden? Any 3L bottom ends looking for a home?

[The Real Roadrunner]

Ummm, a few. 2jzgte vvti, 2jzgte, 2jzge and 5 spare 1jzgte's

what you thinking?

[TIMTAMS]

phill stay out of spare parts shed!!! Linden i bagged em first remember!

I buzz every engine i own at one stage or another.....Then again i blow up every engine ive ever owned so i should stay out of it.

[1JZ-Rolla]

Ummm, a few. 2jzgte vvti, 2jzgte, 2jzge and 5 spare 1jzgte's

what you thinking?

I'm thinking that the best match for a bigger turbo is also a bigger capacity short motor.

I've been meaning to grab a spare 1JZGTE for a rainy day, but makes sense to store a 3 litre instead

[woggin]

or stroker kit!

[The Real Roadrunner]

or stroker kit!

for what? a 1jz or 2jz?

stroked 1jz=2jz
stroked 2jz= why bother? the make enough grunt as a 3L. the bigger strokers don't actually make more power, just more midrange / average power.



Timtams, you've been banned remember don't come back without a 12

cheers
linden

[1JZ-Rolla]

Definitely won't be stroking either Three litre 2JZ bottom end will do me fine, even with the 1JZ head (to simplify manifolds etc).

Linden, how important do you view the piston oil-squirters in a mildly powered (350wkw) 2JZ bottom end? I'm finding it hard to look past a naturally aspirated bottom end for the "cheap" build.