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Safc 2 + Auto Gear Box

Mayuri Krab
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Mayuri Krab Grand Master

Mayuri Krab

Posted
Posted

Hey guys,

I recently got my SAFC II installed & tuned for my auto R33 GTS-T with the following support mods:

-3" turbo back exhaust with high flow CAT

-Apexi POD

-R34 GTT SMIC

-Turbosmart boost controller set at 10PSI

Car made ~240rwhp

On the way back yesterday & driving to uni today I noticed that the auto box's "shift points" have moved lower compared to b4 & its behavior have changed compared to b4.

B4 the "min speed" at which gear changes occur were at ~25, 50 & 70km/h, now the gear changes will happen at 20, 40 & 60km/h & the box also seems to be much "willing" to move up to overdrive as soon as possible compared to b4.

For example, before hand, as long as I apply a constant throttle (even if its a small one) the car will hold onto 2nd gear until 70km/h, to get it to change at the "min speed" of 50km/h I need to reach 50km/h, back off the throttle & let it change. I have to do the same thing for it to go from 3rd to overdrive.

But now, if I still apply a small constant throttle, it will change from 1st to 2nd to 3rd to OD all by itself without me having to do any of the above (lifting off throttle to let it change).

Also the speed at which the gear changes seem to have being moved down lower, as now gear changes occur at 20, 40 & 60 instead of the old 25, '50' & '70'.

As a result, b4 if I were driving at 60km/h the car would stay in 3rd gear at ~2500rpm, but now it would change into OD ~<2000rpm.

Also the gearbox also seem to be much more sensitive to throttle & load compared to b4 & will happily drop down gears compared to b4, where it would just act lazy & stay in the same gear unless I'm really flooring it.

Finally the gear changes seem to be faster compared to b4; it like to hang there for a sec or so b4 changing but now its just jumping through them at rapid rate.

Basically I would like to know is how is this even possible? Can a SAFC alter the gear box logic? My understanding was the all it does is change fuel mixtures at different rpm points to avoid the car running rich due to the extra boost & stock ECU. Or is this caused by something else?

I got the SMIC & boost controller installed at the same time as the SAFC, but I doubt they got anything to do with the change of behavior of the auto box.

Any info would be appreciated

Cheers.

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The Dan Grand Master

The Dan

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Posted

Sounds like before it was shit and now it is working properly. The shop who tuned it probably noticed it was shit and then noticed the oil level in the biz was low so topped it up.

Have you tried contacting the shop who tuned it?

iseekool Veteran

iseekool

Posted
Posted

Possibly with the increased torque you are getting the auto will tend to upshift earlier.

Does the car feel sluggish/flatspot in anyway during the early upshifts?

Having upshift earlier with no side effects is not such a bad thing you save a little on fuel.

Mayuri Krab Grand Master

Mayuri Krab

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  • Author
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Sounds like before it was shit and now it is working properly. The shop who tuned it probably noticed it was shit and then noticed the oil level in the biz was low so topped it up.

Have you tried contacting the shop who tuned it?

LOL, this was one of the idea that came to mind while I was looking at the subject, compared to b4 the box does indeed feels & act like all the other auto box cars I have driven (91 VN commodore & 02 Camry) in that it doesn't hold onto each gear for a long time unless I'm flooring it or have power mode on.

Haven't contacted the shop yet, might do that on SAT, damm too much uni work going on.

Maybe they cut the TPS wire (the one on the plug the transmission uses) instead of splicing into it.

I'm guessing thats a bad thing? Sorry don't really know much about all the electronic stuff.

Possibly with the increased torque you are getting the auto will tend to upshift earlier.

Does the car feel sluggish/flatspot in anyway during the early upshifts?

Having upshift earlier with no side effects is not such a bad thing you save a little on fuel.

I didn't notice any sluggish/flatspot during the shifts, the gear shifts are actually better than before, before, the gear change from 1st to 2nd were like a big 'jerk', & now the 1st gear change is more like a soft 'click' simlilar with the other gear changes. The gear changes are still not as smooth as the 02 Camry, but I take that is due to the old condition of the auto box.

Seems all good so far, the only thing I don't like atm is that, since it will change into final gear at 60km/h & now its much more sensitive to throttle it will happliy downshift to 3rd if my foot was even slightly down too much on the gas & go into 4th again when I ease of the throttle.

Atm I'm getting around this problem by just turning Overdrive off on normal roads & only turning it on, on roads with speed limit of 70km/h or higher.

Lastly its kinda hard to maintain the speed limit with this increase in power, torque & throttle response. I need to work on upgrading my regular granny driving style to super granny style to get it under control. :thumbsup:

  • 3 weeks later...
Mayuri Krab Grand Master

Mayuri Krab

Posted
  • Author
Posted

Happy to report that my fuel usage went down from ~13.5l/100km down to the 11s range :)

Its now on par with my mum's Camry but with much more P-O-W-E-R!!! <screams out in Jermy Clarkson tone>

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