Max BHP an Auto box can take

[kalp]

Hi,

As above please.

would like to know your mods to your auto please.

I currently have 95 ep82, imported it back in 2009 as I was bored due to a fractured ankle.

the car came with a turbo timer & quad lights, other than that not really done anything to it apart from a Powerflow exhaust.

I'm getting the itch now to get some mods to it, id like to do a brake upgrade first before deciding on engine mods, and taking it from there.

So I will be doing a lot of reading and asking questions if needed.

Regards

Kalp

 

[Paul_JJ]

I ran 177bhp for over a year then the gearbox went due to the overheating and possible blocked gearbox oil filter, also we don't know if the box was abused in Japan or not, as standing in traffic for many hours don't do any good to the autoboxes, as well as going up the hill - as that is usual in Japan. I did 14.5 sec running just 0.9 bar on a standard turbo and road legal tyres -)

I'm pretty sure that you can run 200 bhp on the autoboxes, HOWEVER you will need an additional oil cooler for the gearbox (it has 1 already), replace the oil (and be very careful what oil you put in) and do an oil filter replacement, at least once in 2 years. I would rather stick with Original Toyota oil Dexron 3 and not put anything else - my personal opinion. The operational oil temperature must be within 82-87C in my opinion, once the gearbox starts overheating the oil starts to degrade and then the problems starts to occur.

Once you get a knock while putting the gearbox in to R gear, start looking for another gearbox as sooner or later it will fail -))))))


PM me for more details if you want to.

Paul

 

[kalp]

I ran 177bhp for over a year then the gearbox went due to the overheating and possible blocked gearbox oil filter, also we don't know if the box was abused in Japan or not, as standing in traffic for many hours don't do any good to the autoboxes, as well as going up the hill - as that is usual in Japan. I did 14.5 sec running just 0.9 bar on a standard turbo and road legal tyres -)

I'm pretty sure that you can run 200 bhp on the autoboxes, HOWEVER you will need an additional oil cooler for the gearbox (it has 1 already), replace the oil (and be very careful what oil you put in) and do an oil filter replacement, at least once in 2 years. I would rather stick with Original Toyota oil Dexron 3 and not put anything else - my personal opinion. The operational oil temperature must be within 82-87C in my opinion, once the gearbox starts overheating the oil starts to degrade and then the problems starts to occur.

Once you get a knock while putting the gearbox in to R gear, start looking for another gearbox as sooner or later it will fail -))))))


PM me for more details if you want to.

Paul

Hello Paul,

Am I right to assume to use OEM gearbox oil filter also?

Do you have a recommendation for the additional oil cooler and where I could locate on from please?

Many thanks

Kalp

 

[Paul_JJ]

YES just the OEM filter the only one which will fit -) an expensive one, but no need to replace it very often. Jay can put some info as well as he drives an Auto as well.

Get any oil cooler even the one for the engine oil, you need just a small one really, stick it anywhere you like and be happy. I'd put it in front of the radiator.

 

[Jay]

It's all about the cooling, once you overheat the fluid the damage is done. Keeping the fluid fresh, the filter clean and the heat down will help preserve the life expectancy of the autobox.

I'd aim to keep it under the 200bhp mark and aim for response rather than outright power figures.

My progress thread if it's of any interest is HERE.

Jay

 

[Rev]

I few things to note re Temperature

> oil overfilling the auto box causes frothing.
> I notice my Gear box doesn't seem to lock in OD so slipping on steepish grade has to be managed.
> You can check the max temp of the box with this ' stick on Temp gauge '
http://www.ashcroft-transmissions.co.uk/temperature-strip.html

> When my box failed it was idleing in traffic on a hot day. Afterwards I noticed the auto tran cooler had been pushed hard against the radiator. Normal operating temp of trans I think is up to 80c my radiator was likely 100C so was heating up the auto trans.
Maybe someone has the normal operating temp spec. for the Starlet box to confirm this issue?

> I guess depending on turbo setup etc before the convertor locks up you would want strong, smooth torque but not torque causing excessive slip. After that it becomes a matter of the limit of the convertor ( providing the torque convertor Stator is functioning correctly - see below )

Torque convertor Diagnois. ( para phrase from toyota technical training )
Stator misfunction.
As auto tran fluid reaches the coupling point if the stator was to lock up in both directions low end would be fine but the impellor and turbine fluid flow would bounce off the stator veins in the opposite direction causing temp to go up. Continued operation can over heat the fluid and effect engine operating temp.
If the stator was to free wheel in both directions low end would be poor and top end fine.