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Car so nice, bought twice
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Discussion Starter · #1 ·
Felt a bit adventurous and decided to ebay the ECU off a wrecked 2008 EX-L Sedan (2.4...obviously). It seems that the only difference between the 190 and 177 hp versions are a) bigger exhaust diameter (2.25 vs 2.5") and b) higher rev limit.

Assuming I can actually get the ECU installed, I plan on taking it to the same dyno place I used previously and doing a back to back run with the ECU reset to negate any sort of "learned" advantage. It should be immediately obvious if the rev limit has been raised. Some problems I foresee:

  • -EX-L has a lot more gear than the LX has. Who knows if the ecu is going to freak out because seat heaters are missing. Navigation vs. no navigation...list goes on and on.
  • -Immobilizer might be screwed without reflashing the ecu. I'm hoping the immobilizer module is contained to the steering column. I know it talks to the ECU, but I'm hoping it's just a "go/no go" signal.
  • -The '08 might not have any number of ECU updates that have occurred in the 5 years since it came out. I seem to recall there being a few that are mentioned around here.

But either way, I'm going to take one for the team and see what happens with an ecu swap. On the plus side, swapping ECU's is really pretty easy...already removed my ecu once to look at it.
 

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i think you might have problems with the immobilizer. Not directly pertinent, but we did a swap like this on my buddy's sentra and we couldnt get it going with the new ECU...
 

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Car so nice, bought twice
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Discussion Starter · #4 ·
i think you might have problems with the immobilizer. Not directly pertinent, but we did a swap like this on my buddy's sentra and we couldnt get it going with the new ECU...
A guy on a Civic forum seemed to have issues with the immobilizer as well, but he was trying to do a Canadian -> US ecu swap. If I run into that issue, there's 2 solutions: take to dealer and pay an hour of labor for a reflash (and ecu update), or attempt to directly provide 12V to the fuel pump, which is all the immobilizer really controls. I might try option b) first, since I already have a kill switch tapped into that circuit that I could probably hook up to a battery. I've been curious to try if directly bypassing the fuel pump relay would let people steal our cars ;)
 

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Car so nice, bought twice
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Discussion Starter · #7 ·
Had to cancel the order because I missed the 2 letters: "MT" in the description. I caught the mistake when I plugged the VIN # into owner's link.

There's 2 more viable options on the Bay that I've sent inquiries to the sellers. I want the VIN number to a) confirm the correct trim level and b) make sure that if I need to take it to the dealer for flashing I have the donor's VIN.


Just to be sure: there's no such thing as a 177HP coupe correct?
 

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Had to cancel the order because I missed the 2 letters: "MT" in the description. I caught the mistake when I plugged the VIN # into owner's link.

There's 2 more viable options on the Bay that I've sent inquiries to the sellers. I want the VIN number to a) confirm the correct trim level and b) make sure that if I need to take it to the dealer for flashing I have the donor's VIN.


Just to be sure: there's no such thing as a 177HP coupe correct?
nope!!

only sedan LX /LX-P comes in 177... every other i4 is 190
 

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Car so nice, bought twice
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Discussion Starter · #9 ·
OK new ECU inbound. This one is off a 2010 EX that got nailed in the side:



Guy did say that yes, they're going to have to recode the keys to the ECU. I figure I'll just drive to one of my local dealers and do the swap there since only basic sockets are needed to swap it.
 

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Wisdom Born of Age
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Would be great if it works, but doesn't the EX have different transmission gearing? Is your thinking that the larger exhaust at higher RPM is the only difference?
 

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Car so nice, bought twice
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Discussion Starter · #12 ·
Would be great if it works, but doesn't the EX have different transmission gearing? Is your thinking that the larger exhaust at higher RPM is the only difference?
Yep, that's my thinking. Even though I'm leaving the exhaust alone, I assume removing the precat is roughly equivalent to having larger diameter piping. From my dyno results, it seemed that the HP kept climbing all the way until redline, so I assume the line will keep going for an extra 300 rpm. The TQ is supposed to be +1, but we don't know if the torque curve looks better while the peak is the same.

I know the gearing is a little bit different too, but at least we'll (hopefully) settle whether the ecu alone improves performance.
 

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Yep, that's my thinking. Even though I'm leaving the exhaust alone, I assume removing the precat is roughly equivalent to having larger diameter piping. From my dyno results, it seemed that the HP kept climbing all the way until redline, so I assume the line will keep going for an extra 300 rpm. The TQ is supposed to be +1, but we don't know if the torque curve looks better while the peak is the same.

I know the gearing is a little bit different too, but at least we'll (hopefully) settle whether the ecu alone improves performance.
this can be like a little reflash for us LX owners if this works and if there is a performance increase. im gonna do 2.5 inch piping very soon anyway
 

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I think it will work, but the power difference is mostly at high RPM. Very hard to tell the difference driving an LX vs EX or EXL
 

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Car so nice, bought twice
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Discussion Starter · #15 ·
I think it will work, but the power difference is mostly at high RPM. Very hard to tell the difference driving an LX vs EX or EXL
Indeed, I suspect the main reason for the change was to simply say "buy an EX..it has more power*" *in an RPM range you'll rarely ever use If the immobilizer has to be reflashed to swap ecu's then back to back dyno runs is out of the question. I'll look into the fuel pump relay bypass, but I suspect that the immobilizer is also tied into the spark system as well. I'll still giggle like a schoolgirl if the tach goes past the redline :naughty:
 

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mobiless2
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I'll still giggle like a schoolgirl if the tach goes past the redline :naughty:
If it works you could buy the cluster from donor car to get higher rpm tach
 

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Car so nice, bought twice
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Discussion Starter · #18 ·
Alright, D-Day is tomorrow. ECU coming in the mail (2010 EX-L, 2.4L, AT, Federal Emissions) and I've got an appointment scheduled to have a tech give flashing a shot. You know you're doing something cool when he has to put you on hold to talk to the senior tech :) They think it's plausible that it'll work, but no guarantees.

Cost for the reflashing / immobilizer stuff is $125. The ECU itself ran $125 as well. They said that they can also update the 2010 ECU to make sure it has all the latest TSB's (if any), but the ECUs aren't "re-programmable" as in you can't drop an EX firmware on an LX ECU. I'll confirm this last part tomorrow. My guess is you probably can, but Honda only provides update files or something.
 

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Corvalis TTX
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Alright, D-Day is tomorrow. ECU coming in the mail (2010 EX-L, 2.4L, AT, Federal Emissions) and I've got an appointment scheduled to have a tech give flashing a shot. You know you're doing something cool when he has to put you on hold to talk to the senior tech :) They think it's plausible that it'll work, but no guarantees.

Cost for the reflashing / immobilizer stuff is $125. The ECU itself ran $125 as well. They said that they can also update the 2010 ECU to make sure it has all the latest TSB's (if any), but the ECUs aren't "re-programmable" as in you can't drop an EX firmware on an LX ECU. I'll confirm this last part tomorrow. My guess is you probably can, but Honda only provides update files or something.
I'm really curious to see how this pans out. Keep us posted.
 

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Alright, D-Day is tomorrow. ECU coming in the mail (2010 EX-L, 2.4L, AT, Federal Emissions) and I've got an appointment scheduled to have a tech give flashing a shot. You know you're doing something cool when he has to put you on hold to talk to the senior tech :) They think it's plausible that it'll work, but no guarantees.

Cost for the reflashing / immobilizer stuff is $125. The ECU itself ran $125 as well. They said that they can also update the 2010 ECU to make sure it has all the latest TSB's (if any), but the ECUs aren't "re-programmable" as in you can't drop an EX firmware on an LX ECU. I'll confirm this last part tomorrow. My guess is you probably can, but Honda only provides update files or something.
This sounds awesome, I too look forward to your results


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