Are there computer issues when you swap a '92-'95 CX/VX 5-speed tranny into a '94-'95 EX?
Or other issues?

I gave up on my previous plan to swap a CX/VX tranny into a '96+ EX due to OBDII CELs. Would I be OK swapping into the pre-OBDII '94-'95 EX?

My aim is super MPG. Finding a stock HX at reasonable price would be ideal but they are tough to find. Thus thinking about a swap.

Thanks!



Modified by brucepick at 2:36 AM 9/22/2008

 

mechanically it will be simple, with an ECU tune it will be fine.
The ECU knows the trans ratios so it can calculate which gear it's in.(RPM vs speed) If that's wrong, you will have drive ability and other strange issues.

Also since you're going to have to tune the ECU, you can tune it for better mpg. Especially great for mpg if you're willing to run a wideband full time.

 

It's plug and play.

You do not a retune for changing the gear ratios of the transmission....especially a stock one.

 

I'm going to have to disagree... when he's cruising down the road in 3rd with the VX trans it's a big deal that the P28 will think he's in 5th.

There is some decent fuel and ignition difference between those gears. Not to mention since the ECU will see everything above 3nd gear as 5th gear, those changes will not take effect when going to 4th and 5th. (that much over the set ratios may even set some code, I don't know what it will do for sure)

this is of course assuming the OP is talking the EX engine mated to the VX/CX trans. And not the VX engine and trans in the EX shell.

 

The fuel map is based mostly off O2, RPM, MAP, and TPS...

The ECM doesn't care what gear you are in either- and it certainly does not adjust the map based off of the gear it's in....

 

OK, I wonder if you guys can come to a single opinion on this. You both know way more than I do.

To clarify - the plan would be an original EX engine with a VX/CX 5-speed. I'm not up to the job of changing the ECM/ECU and remapping. I'm willing to pay a mechanic buddy to swap the tranny though.

 

there is slight fueling differences between gears, but mostly it's ignition.

Take a look at eCtune or Hondata setups. (Crome to a point)
Load in 1st is VERY different than load in 5th. Which requires very different ignition handling.
Granted the load on the engine will be the same in his 3rd gear as the old trans's 3rd, but 4th and 5th will be flapping in the breeze as far as how the ECU will handle it.

brucepick - if you want a definitive answer, post the question over at PGMFI. ( http://forum.pgmfi.org/viewforum.php?f=40 )
A lot of the guys over there know more about this than I do.

 

Relic is correct, esp. with 5th gear adding timing, not an issue for NA motor, but for a boosted motor it could be deadly.

Also expect gas mileage to get worse along with clutch wear.

 

Thank you all for your input on this.

Orig. question is now a non-issue.
Today I bought a '97 HX, 5-speed, silver gray, a/c, power windows, with HX rims.

Needs just a bit of attention but I think it will be a good long distance commuter (I drive 50 mi. each way to work).

 

great find. congrats.
make sure the O2 is in good shape and the car will make you smile everytime you drive past a gas station.