Boost cut off

[crispone]

Not on an S/C 'lara... but the principles should be the same:

On my '89 Supra... WHEN I had the AUTO in it... (A FULLY built HKS unit with an Art Carr converter...) When I would WOT through the gears, (all the time... @15psi on a regular basis...) my setup would HOLD BOOST all the way through the tranny... with some fluctuation when gears would "lock-in". I think my setup was not the "norm", but I HELD the boost level through the shifts... then again, the unit was set up for into 400hp.

THEN, when I converted to a FIVE speed, my experience is the SNAP back down to VACUUM as soon as you back off load with a accel lift OR disengaging the clutch. One moment, 15-16psi... then next instant, Psssssshhhhhtttt-t-t-t-t! ...and VACUUUUUM!


Sounds normal, but I have heard that "boosting" through the shift requires special tranny prep. I even ran "Super Synthetic ATF" from Japan @ $39.99/liter (x8!!!) as it was "formulated" to work with my plates.


-crisp

[Dawgz]

i have full synthetic in the tranny, dono about the "super synthetic" tho lol.

[Eye8Pussies]

Not on an S/C 'lara... but the principles should be the same:

On my '89 Supra... WHEN I had the AUTO in it... (A FULLY built HKS unit with an Art Carr converter...) When I would WOT through the gears, (all the time... @15psi on a regular basis...) my setup would HOLD BOOST all the way through the tranny... with some fluctuation when gears would "lock-in". I think my setup was not the "norm", but I HELD the boost level through the shifts... then again, the unit was set up for into 400hp.

THEN, when I converted to a FIVE speed, my experience is the SNAP back down to VACUUM as soon as you back off load with a accel lift OR disengaging the clutch. One moment, 15-16psi... then next instant, Psssssshhhhhtttt-t-t-t-t! ...and VACUUUUUM!


Sounds normal, but I have heard that "boosting" through the shift requires special tranny prep. I even ran "Super Synthetic ATF" from Japan @ $39.99/liter (x8!!!) as it was "formulated" to work with my plates.


-crisp

The question though, is if your supra was originally boosted with the 7mgte (I don't know). Or if you did a custom turbo setup on your 7mge.

Also though, I don't know how the 7mgte ecus were programmed either. Most cars that come with boost from the factory with an automatic, the same functions of an ebc are built into the automatic ecu to cut boosts in between shifts to save the transmission.

But in the case of a supra though, which was supposed to be a high performance car, the stock tranny may have been built to just take the boost throughout gears and the ecu was not designed to cut boost during shifts.


and Dawgs- there isn't much that you can do right now anyway. You're doing all that you can anyway at the moment. Figure out your power problem first before you worry about your tranny. At 170whp, there is really nothing to worry your tranny about. Afterwards, if you are still worried about your tranny, hook up your ebc properly and it *should* solve your problems (and you can also tell us if it cuts boost down to 0psi during shifts as well )

[Paladin06Greg]

Call TRD..

[Dawgz]

I called TRD, a really cool jamaican guy was helping me with this, he said it doesnt really have to go to 0, as long as it moves back a bit, ur fine.

eh?

[Eye8Pussies]

interesting.....

then what's the point of the ebc at all really then? even mine (where the ebc can't be hooked up), the boost goes down a bit during shifts and I've hit my reve limiter many times (by accident) with no ill effects

[Dawgz]

i just noticed from a vid i took of my boost gauge while i was giving it gas, that my boost hits 2.5 and then slowly creeps to 3psi but doesnt go any further.

I cant wait to get Greg's 4psi pulley in, im gonna see if there is a size diffrence, if so ill install it and get back with the info, hopefully with 4psi of boost.