Fordmods Logo

ECU changes effecting diff 

 

Page 3 of 4 [ 48 posts ] Go to page Previous  1, 2, 3, 4  Next

 
Posted: Sun Mar 19, 2006 7:34 pm 
Getting Side Ways
Offline

Age: 39

Posts: 868

Joined: 23rd Sep 2005

Ride: eb falcon

Location: kadina
SA, Australia

i have argued this with people before, i agree that the ecu reads tailshaft rpm not axle/wheel speed, so unless theres a ratio change between the crank and the tailshaft, how possibly can changing the axle ratio affect shift points??

it knows to change gears at say 2000 tailshaft rpm, which may be 80kmh road speed, if you alter the final drive ratio, it will still shift at 2000rpm of the t/s which will be the same engine rpm as before, but me be a different road speed

 

_________________

EB 4L, 8.4:1, R154, GT4202r, 4in exhaust, Greenslade Engineering exhaust manifold, plenum chamber, 90mm throttle, Garrett W2A cooler, Surecam custom, autronic SM4, Bosch 120lb, Crane HI-6, LX-92, LM-1, Turbosmart Reg, 2x bosch 044, turbosmart 48 gate. 470kw+ @ 18PSI

Top
 Profile  
 
 
Posted: Sun Mar 19, 2006 7:43 pm 
Getting Side Ways
Offline

Posts: 6449

Joined: 11th Nov 2004

ebs_4l wrote:
i have argued this with people before, i agree that the ecu reads tailshaft rpm not axle/wheel speed, so unless theres a ratio change between the crank and the tailshaft, how possibly can changing the axle ratio affect shift points??

it knows to change gears at say 2000 tailshaft rpm, which may be 80kmh road speed, if you alter the final drive ratio, it will still shift at 2000rpm of the t/s which will be the same engine rpm as before, but me be a different road speed


thats exactly right. but most people when changing diff gears also change the speedo gear and thats where the problems start
Top
 Profile  
 
 
Posted: Sun Mar 19, 2006 8:35 pm 
ACT Cruise Moderator
Offline
User avatar

Age: 42

Posts: 6249

Joined: 24th Nov 2004

Ride: '06 BF GT-P

Power: 293 rwkw

Location: Canberra
ACT, Australia

The ECU shifts based on road speed, which it figures out assuming a known diff ratio (which is set in the ECU's code).

I know this cause I've spent the past 8 months hacking though ECU bin files in an effort to make chips for them... The tables in the ECU, are based off load and speed, NOT RPM.

The ECU gets the speed from the dash - so yes, if you just change the diff, everythign will be fine, but you're speedo will be wrong. If you then change teh speedo gear so the speedo will be right - bam your shifts will then be wrong. So change ECU to match.

 

_________________

1998 DL LTD in Sparkling Burgundy, daily, 302W, stereo, slow
2006 BF GT-P in Ego, mods. Supercharged 5.8L all alloy modular

Top
 Profile  
 
 
Posted: Sun Mar 19, 2006 10:01 pm 
Getting Side Ways
Offline

Posts: 6449

Joined: 11th Nov 2004

data_mine wrote:
The ECU shifts based on road speed, which it figures out assuming a known diff ratio (which is set in the ECU's code).

I know this cause I've spent the past 8 months hacking though ECU bin files in an effort to make chips for them... The tables in the ECU, are based off load and speed, NOT RPM.


The ECU gets the speed from the dash - so yes, if you just change the diff, everythign will be fine, but you're speedo will be wrong. If you then change teh speedo gear so the speedo will be right - bam your shifts will then be wrong. So change ECU to match.


so the speedo signal goes straight to the dash then to the ECU??
Top
 Profile  
 
 
Posted: Sun Mar 19, 2006 10:02 pm 
ACT Cruise Moderator
Offline
User avatar

Age: 42

Posts: 6249

Joined: 24th Nov 2004

Ride: '06 BF GT-P

Power: 293 rwkw

Location: Canberra
ACT, Australia

yup

For some harmless fun, pull the INST_BATT fuse from the fuse panel, the cluster will go dead, and your ECU will go into limp mode because it's not getting a speed signal. Auto will be stuck in 3rd unless you manual shift it.

 

_________________

1998 DL LTD in Sparkling Burgundy, daily, 302W, stereo, slow
2006 BF GT-P in Ego, mods. Supercharged 5.8L all alloy modular

Top
 Profile  
 
 
Posted: Sun Mar 19, 2006 11:48 pm 
Getting Side Ways
Offline
User avatar

Age: 52

Posts: 3763

Joined: 25th Nov 2004

Gallery: 6 images

Ride: EFII 5.8 NOS TerroristGhia

Power: 274 rwkw

Location: Sydney Australia
NSW, Australia

Ok data, but can you tell me how to fix the signl to the Auto computer as the V8 has a sepearate computer. I have fixed my speedo form a ratio change form 3.45 to 3.93, by using an XD transducer and a 21tooth cog. This was mal woods advice, but as a s***, it now shifts into the next gear in econ mode at 5800rpm, where as previously it shifted at 5400rpm. I have yet to use full throttle with the econ turned off. This is not good. I have the jaycar speedo corrector, and would like to get acurate speedo and correct shifts, so can i change the signal back to normal using the corrector and sending it to the auto comp. If so, which bloodly wire do i need to hack.
Brett

 

_________________

The Terrorist ED Retired due to RUST.
The TerrosistGhia, EF Ghia 351 EFI 5 Speed.
Millennium Falcon, Sleeper EL DOHC 6 Speed Manual EFI LPG
Member#1131
I didn't Vote for Multiculturalism, DID YOU!!!

Top
 Profile  
 
 
Posted: Mon Mar 20, 2006 1:26 am 
ACT Cruise Moderator
Offline
User avatar

Age: 42

Posts: 6249

Joined: 24th Nov 2004

Ride: '06 BF GT-P

Power: 293 rwkw

Location: Canberra
ACT, Australia

I'm not sure how the auto controllers work on the EA's and V8's. Wanna loan me you'rs to play with for a bit...

I'd say (just speculating), the auto box would get it's speed signal from the dash as the 6's do. Just a matter of ensuring the signal IT get's is appropriate for teh shift points you want, and the dash gets the right signal to show the correct speed. You'd need the speedo corrector on the wire bwtteen the dash and auto controller. Cause would'nt a EF fairmont 8 ECU be expecting a 3.23 diff (you've gone very wild on it)?

edit: As for wiring, I'd be looking for a pin labeled VSS possibly. But I dunno having not played with a e-series 8.

 

_________________

1998 DL LTD in Sparkling Burgundy, daily, 302W, stereo, slow
2006 BF GT-P in Ego, mods. Supercharged 5.8L all alloy modular

Top
 Profile  
 
 
Posted: Mon Mar 20, 2006 6:37 am 
Getting Side Ways
Offline
User avatar

Age: 52

Posts: 3763

Joined: 25th Nov 2004

Gallery: 6 images

Ride: EFII 5.8 NOS TerroristGhia

Power: 274 rwkw

Location: Sydney Australia
NSW, Australia

Not too wild, went from 3.45 factory fitted to 3.93. Lets just say that it is now very snappy. Would be happy to lend it to you, but then what do i do for wheels
Brett

 

_________________

The Terrorist ED Retired due to RUST.
The TerrosistGhia, EF Ghia 351 EFI 5 Speed.
Millennium Falcon, Sleeper EL DOHC 6 Speed Manual EFI LPG
Member#1131
I didn't Vote for Multiculturalism, DID YOU!!!

Top
 Profile  
 
 
Posted: Mon Mar 20, 2006 9:39 am 
ACT Cruise Moderator
Offline
User avatar

Age: 42

Posts: 6249

Joined: 24th Nov 2004

Ride: '06 BF GT-P

Power: 293 rwkw

Location: Canberra
ACT, Australia

Just did some number crunching.

With a 3.45 stock diff, you're ECU would be programmed for redline changes @
86, 141, 180 (205 speed limited)

The 3.93 ratio gives you maximum speeds in each gear of
76, 124, 180

So you need to knock 10,20, and 30KM/H off each shift point.

(that's road speed assuming 235/45R17 tyres, but if you're tyres are sized right, it'll be very close).

One thing I found with mine when I had a mismatched ECU (3.08 ECU with a 3.45) was it'd change when you hit the rev limiter. So I don't think you'll do any damage in the mean time.

Oh, and once you get the 427 I'll swap you with mine for a bit.

 

_________________

1998 DL LTD in Sparkling Burgundy, daily, 302W, stereo, slow
2006 BF GT-P in Ego, mods. Supercharged 5.8L all alloy modular

Top
 Profile  
 
 
Posted: Mon Mar 20, 2006 10:39 am 
Getting Side Ways
Offline

Posts: 6449

Joined: 11th Nov 2004

data_mine wrote:
yup

For some harmless fun, pull the INST_BATT fuse from the fuse panel, the cluster will go dead, and your ECU will go into limp mode because it's not getting a speed signal. Auto will be stuck in 3rd unless you manual shift it.


thats interesting. i'm assuming the the jaycer converter will still work if fitted after the dash

it would be interesting to fit one and play with shift points at the drags after making a few mods like cam shafts. although still being limited the ver limit, there would be some interesting results.
Top
 Profile  
 
 
Posted: Mon Mar 20, 2006 12:05 pm 
Getting Side Ways
Offline
User avatar

Posts: 681

Joined: 3rd Apr 2005

Gallery: 24 images

Ride: BF MKII Ghia

So in my el ghia what would happen if i changed from a 3.23 to a 3.45.

i would have thought that i change the speedo sensor gear and everthing would be ok but after readinghtis thread im now confused LOL easily done
Top
 Profile  
 
 
Posted: Mon Mar 20, 2006 12:53 pm 
Getting Side Ways
Offline
User avatar

Age: 40

Posts: 753

Joined: 6th Dec 2004

Gallery: 12 images

Ride: 98 DL LTD | 71 XY

Location: Bellevue
WA, Australia

Hmmm.. and what would happen in my case.. I'm not spozed to have the xr6 ecu in my ghia but i do and im running a 3.23. Does this mean its shifting to early or late?

 

_________________

RIP Scotty
Still Doin It For Ya Mate

Top
 Profile  
 
 
Posted: Mon Mar 20, 2006 1:20 pm 
Getting Side Ways
Offline
User avatar

Posts: 681

Joined: 3rd Apr 2005

Gallery: 24 images

Ride: BF MKII Ghia

lol atleast im not the only one confused. what advantages is ther of having the xr6 ecu instead of the ghia one?
Top
 Profile  
 
 
Posted: Mon Mar 20, 2006 2:05 pm 
Getting Side Ways
Offline
User avatar

Age: 52

Posts: 3763

Joined: 25th Nov 2004

Gallery: 6 images

Ride: EFII 5.8 NOS TerroristGhia

Power: 274 rwkw

Location: Sydney Australia
NSW, Australia

No, bro, i dont have a Speed limiter, got an EF XR8 ECU, which doesnt control the shift points as it is an 8. Also the V8 does not have a revlimiter, because i have been known to rev it past the limit of the tacho once or twice whilst racing. And as for the 427, this wont make any difference, as the EMS will be in control of the Motor, and have a conservative redline of 7000.But i would like to sort it out now before the biggun goes in
Brett

 

_________________

The Terrorist ED Retired due to RUST.
The TerrosistGhia, EF Ghia 351 EFI 5 Speed.
Millennium Falcon, Sleeper EL DOHC 6 Speed Manual EFI LPG
Member#1131
I didn't Vote for Multiculturalism, DID YOU!!!

Top
 Profile  
 
 
Posted: Mon Mar 20, 2006 2:07 pm 
Getting Side Ways
Offline
User avatar

Age: 40

Posts: 753

Joined: 6th Dec 2004

Gallery: 12 images

Ride: 98 DL LTD | 71 XY

Location: Bellevue
WA, Australia

seems to run better, i have cam, zorst, pacemakers, filter, Motor only done 20,000. Idles alot better and shifts diffrent cause mine's only a 94.. didnt have a xr6 motor in her

 

_________________

RIP Scotty
Still Doin It For Ya Mate

Top
 Profile  
 
Display posts from previous:
Sort by  
 Page 3 of 4  [ 48 posts ]  Go to page Previous  1, 2, 3, 4  Next

Who is online

Users browsing this forum: No registered users and 6 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

 

 

It is currently Fri Mar 29, 2024 6:09 pm All times are UTC + 11 hours

 

 

(c)2014 Total Web Solutions Australia - Australian Web Hosting and Domain Names