Ecu

bendts

bendts

Well-known member
Jan 27, 2015
277
18
Farmland
So i read on the interwebs someplace that the ECU for the 4.0 and 4.6 are the same, but that the dealer can select in the ECU software whether its hooked to a a 4 or 4.6.

Is this so... And what would the difference be in performance or just basic daily driving.

Or did the interweb lie to me.

Thanks
 
D

discostew

Well-known member
Sep 14, 2010
7,745
1,026
Northern Illinois
The ecu is the same part. Yes it can be programmed to know it is running a 4.6 instead of the 4.0 it used to run. I know there is no substitute for cubic inches but.....your talking about 6 tenths of a fucking liter. I think the fact that the stroke is longer your going to see some improvements in the type of torque we want for off road use. If it was me and my 4.o was running well I wouldn't spend any time or money to switch out to a 4.6. If my 4.0 was tits up then I would probably run a 4.6 because bigger is better I suppose.
 
bendts

bendts

Well-known member
Jan 27, 2015
277
18
Farmland
discostew said:
The ecu is the same part. Yes it can be programmed to know it is running a 4.6 instead of the 4.0 it used to run. I know there is no substitute for cubic inches but.....your talking about 6 tenths of a fucking liter. I think the fact that the stroke is longer your going to see some improvements in the type of torque we want for off road use. If it was me and my 4.o was running well I wouldn't spend any time or money to switch out to a 4.6. If my 4.0 was tits up then I would probably run a 4.6 because bigger is better I suppose.
Click to expand...


Well i already rebuilt it as a 4.6 last spring - its running great but was wondering if i will get anymore out of it if the ECU is set for a 4.6 instead of the 4 its set for now.
 
R

robertf

Well-known member
Jan 22, 2006
4,801
366
-
I suspect the 4.0 to 4.6 setting changes the response range to knock sensor input frequencies, nothing to do with ignition or fueling tables
 
jafir

jafir

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May 4, 2011
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Northwest Arkansas
According to what I heard from Mark Adams, on the GEMs it was an option to pick one of the two tunes, if there were actually two stored. On the Bosch you have to reflash the entire ecu with a 4.6 tune.
 
Drillbit

Drillbit

Well-known member
Oct 12, 2005
5,943
1
Glasgow Ky
jafir said:
According to what I heard from Mark Adams, on the GEMs it was an option to pick one of the two tunes, if there were actually two stored. On the Bosch you have to reflash the entire ecu with a 4.6 tune.
Click to expand...

I have known lots of places that swap bosch engines 4.0-4.6 and 4.6-4.0 without changing any settings and the cars drive fine and I can't feel a difference between them and one with a "correct" setting. As I understand it the o2's will compensate for the need for more/less fuel.
 
jafir

jafir

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May 4, 2011
1,628
0
Northwest Arkansas
Drillbit said:
I have known lots of places that swap bosch engines 4.0-4.6 and 4.6-4.0 without changing any settings and the cars drive fine and I can't feel a difference between them and one with a "correct" setting. As I understand it the o2's will compensate for the need for more/less fuel.
Click to expand...

Yeah. I've heard that too. And that makes sense. I just was saying that on a Bosch you cannot just flip a bit on testbook to make it a 4.6.
 
bendts

bendts

Well-known member
Jan 27, 2015
277
18
Farmland
OK thanks - I may call a dealer to see what they would charge - but it is running fine, but wasn't sure if it would run moar better.
 
D

discostew

Well-known member
Sep 14, 2010
7,745
1,026
Northern Illinois
fishEH said:
Yes, but when the regular engine is only 4.0 liters to begin with a 15% increase is fairly significant.
Click to expand...

Fair enough. When you figure it that way I see your point. I think the longer stroke is better for making low end torque. Shorter stroke would be better for high rpm power.
 
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