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R33 S1 + Gt 3071r-sp + Power Fc + Auto

dangerman4

By dangerman4,
in Engines & Forced Induction

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32vspecII Mentor

32vspecII

Posted
Posted (edited)

the stock ecu retards the ignition during gear changes

it must do it for a reason

and the powerfc doesnt do it

there must be issues with not doing it , or the stock ecu woudnt do it either

also this is my 2nd auto skyline

Edited by arkon
mikymouse Rising Star

mikymouse

Posted
Posted

I had an manual ECU in my auto Silvia. It didn't communicate with the auto computer at all. On slow acceleration gearchanges from 1st to 2nd where quite harsh and jerky, as were all gearchanges on releasing the throttle. I don't see why it would be different in your case. The power FC won't cut timing on gearchanges and this will eventually lead to a jerky and rough gearbox. The gearbox oil will heat up, causing deterioration of the internal components (friction bands? clutch plates?). In my case, the Silvia is 15 years old, so I felt it straight away. Your gearbox is still young (and stronger I believe), however it won't be long till you feel the same rough gearchanges. Do you have a transmission oil cooler?

**JaR** Grand Master

**JaR**

Posted
Posted
somone else who knows some more will be able to clarfiy but it believe the r33 box is electronic and needs to be told by the ecu when to change gears, and it communicates with the ecu, and this also allows the ecu to cut timing on gearchange so its not as harsh.

it is electrical. i just had mine replaced not long ago.

dangerman4 Mentor

dangerman4

Posted
  • Author
Posted

all i have to go on is the fact that its in and drives really nice..

it wont be tuned in time for the SA cruise on this weekend but if anyone with a 33 auto dosent believe me then pm me and i will gladly take you for a spin to prove the gearchanges are the same as the standard ecu..

  • 7 months later...
WazR32GTSt Grand Master

WazR32GTSt

Posted
Posted

i know i am diggin up an old thread here..

i wanted to know from the person who started the thread how thier gearbox is going, and how the tune went with the auto?

i don't see how it will be a problem as the engine ECU doesn't control the auto trans anyway... it sends signals to the auto ECU which controls the trans. only the engine ECU is replaced so the auto ECU is still there and doing its thang...

but keen to find out how the trans is holding up

cheers,

Warren

dangerman4 Mentor

dangerman4

Posted
  • Author
Posted
i know i am diggin up an old thread here..

i wanted to know from the person who started the thread how thier gearbox is going, and how the tune went with the auto?

i don't see how it will be a problem as the engine ECU doesn't control the auto trans anyway... it sends signals to the auto ECU which controls the trans. only the engine ECU is replaced so the auto ECU is still there and doing its thang...

but keen to find out how the trans is holding up

cheers,

Warren

Exactly the same as when i put the PFC in the car.

the car has been running at 270 kws for the past six months and is normally driven every day.

All the people on here that say it doesnt work have never tried it.

its as simple as that.

i have just installed a gt3540-IW and it is so smooth to drive.

i cant wait for a response from Paul33.

paulr33 Grand Master

paulr33

Posted
Posted

hi,

in my posts i have said it will work, the engine will start, the car will run, it will drive, it will turn off and so on. but what i did say was that it wont be the same as the factory ecu. this is because the powerfc has no logic shift control. you said 3 posts up that you are seeing detonation on gear change. this to me sounds like the following

1) driving along

2) we are at map points P8, R6

3) auto box goes, ok change gears

4) we are progressing in the map P8 R7 (revs going up)

5) auto box says to powerfc, hey im changing gears drop the timing

6) powerfc doesnt not listen to the autobox communication (its not expecting it)

7) still on P8 R7

8) auto box moves cogs around or does a gear change

9) knock sensor reports detonate detonate detonate

10) we now move to P7 R3

a map tracer of it would certaily prove the theory right or wrong.

i feel this is because when you are on max load afm is seeing air come, so the P axis keeps moving down, revs going up so R keeps going across. bang comes a gear change, revs drop but load doesn't as the throttle body doesn't close on gear change air coming into the system is still quiet high, so its still way down on the load axis ie: timing too advanced during gear change.

i am unsure how much load it will drop on gearchange via the afm, but a map tracer or even datalogit logs should tell you. im not sure (if my theory is correct) that there is a fix for this, as on gearchange on max load if the laod is still fairly high its going to plonk you somewhere near P5-6 where you need some reasonable timing, but on gearchange you need jack all timing, so if the PFC moves to an unused spot (which i dont think it will as P load never drops, thanks to throttle body being open always) then you can tune that spot to have jack all timing and it should be ok

anyhoo if you can get a map tracer it would be good to see what it does on gearchange

paulr33 Grand Master

paulr33

Posted
Posted

sorry i may be mixing up posts, i could have sworn i read a post that said u had detonation on gearchange. anyhoo, read what ive posted and show us a map tracer, would clear up some confusion

dangerman4 Mentor

dangerman4

Posted
  • Author
Posted
sorry i may be mixing up posts, i could have sworn i read a post that said u had detonation on gearchange. anyhoo, read what ive posted and show us a map tracer, would clear up some confusion

im not confused...

aquariuz6 Proficient

aquariuz6

Posted
Posted

I am curious on how this actually goes.

Please keep us auto skyline guys posted.

I am curious to hear if paulr33 is right on the advance timing or simply just the fact that it can work with an PowerFC

paulr33 Grand Master

paulr33

Posted
Posted

everyone has pretty much said it will work, wether it works well is debateable. anywhoo post up a map tracer that would be great. i suspect its not moving much on the load axis, which would mean the timing is too advanced on gear change. do you see knocking at all?

can u get someone to monitor afm v before and during gear change, would be interested to see what it shows

i will add this information to the powerfc FAQ once you can provide it (if you are happy to)

paulr33 Grand Master

paulr33

Posted
Posted

MONITOR, MAP TRACE

PRESS NEXT

it should be ghost trace mode, that it will keep what cells it hits highlighted. drive around in say 2nd gear. press UP to flush previous history. gate it, go through a gear change and then stop. take a photo of the map trace or even plot it onto an excel 20x20 sheet.

It should look like this:

http://paulr33.skylinesaustralia.com/docs/...e-lightload.jpg

http://paulr33.skylinesaustralia.com/docs/...fc-maptrace.jpg

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