Differences between auto and manual engine

[Spartarus]

Originally Posted by steve99

Hmm, i have not pulled di injectors in this car but i was under the inpression that you need to have the same flow numbered di injectors all cylindes ie all number 1 or all 2 or all 3 numbered injectors. Not a mismatched set.

If thats the case that all numbers are same in each cylinder then its possible the di computer doesnt need to know the flow numbers
t

Ah, yes, they are all the same on any given engine, so there are only 3 combinations. Fixed.

[carben100]

Originally Posted by Spartarus

The pipe in that illustration is the same pipe to which I was referring. Yes, it is external. Yes, there's only 1. Sorry, injector cover not valve cover. My bad.

Thanks for clarifying, that's a relief. I'll try to put together a complete list of differences once I have everything sorted out.

Originally Posted by steve99

Hmm, i have not pulled di injectors in this car but i was under the inpression that you need to have the same flow numbered di injectors all cylindes ie all number 1 or all 2 or all 3 numbered injectors. Not a mismatched set.

If thats the case that all numbers are same in each cylinder then its possible the di computer doesnt need to know the flow numbers

Ps looked in service manuals, says use DI injectors with same numbers. In direct injector ecu install remove no memtion of calibrating it or entering flow numbers.


Ive swaped a few engine ecu for people no issues just flashed in the correct engine ecu calibration (you don't rearly need to change vin) no problems with DI ecu or fueling after changing engine ecu.


But safest option would be to keep the di injectors and DI ecu as a set

I just pulled the direct injectors yesterday and they were all the same number. Still replaced them in the same positions on the new motor, no reason not to.

[xwd]

Bumping this as I'm piecing an engine together now.

Does it really matter if the IDU matches the ECU? Is the IDU actually matched to a specific set of injector numbers? I have a complete engine which came with the DIs (obviously all the same #) but not an IDU, I got one of those separately. I'd like to completely assemble the engine and not have to swap parts over from my current engine. Swapping the IDU isn't a big deal if it has to match the CPU, but I'd rather not have to disassemble a bunch of stuff to see what the injector numbers are.

BTW if you are swapping an automatic engine maybe the biggest pain is the automatic has an extra coolant pipe on the bottom section where the oil pan is attached, near the water pump. I'm trying to figure out what to do about that now, Subaru does sell the plug used in the MT cars, but you have to get the pressed in fitting out first.

[SurfAndSand]

Is the exhaust the same on the auto and manual transmissions?
(Can I swap exhaust parts between the two?)

[Trust86]

Originally Posted by xwd

Bumping this as I'm piecing an engine together now.

Does it really matter if the IDU matches the ECU? Is the IDU actually matched to a specific set of injector numbers? I have a complete engine which came with the DIs (obviously all the same #) but not an IDU, I got one of those separately. I'd like to completely assemble the engine and not have to swap parts over from my current engine. Swapping the IDU isn't a big deal if it has to match the CPU, but I'd rather not have to disassemble a bunch of stuff to see what the injector numbers are.

BTW if you are swapping an automatic engine maybe the biggest pain is the automatic has an extra coolant pipe on the bottom section where the oil pan is attached, near the water pump. I'm trying to figure out what to do about that now, Subaru does sell the plug used in the MT cars, but you have to get the pressed in fitting out first.

Ever figure out a solution with the extra coolant pipe?

[finch1750]

Originally Posted by SurfAndSand

Is the exhaust the same on the auto and manual transmissions?
(Can I swap exhaust parts between the two?)

Yes, they are the same. However, there can be clearances issues with certain aftermarket exhausts (mainly combo OP/FP) since the AT gives less clearance moving back.

[FRSBRZGT86FAN]

Originally Posted by finch1750

Yes, they are the same. However, there can be clearances issues with certain aftermarket exhausts (mainly combo OP/FP) since the AT gives less clearance moving back.

Originally Posted by SurfAndSand

Is the exhaust the same on the auto and manual transmissions?
(Can I swap exhaust parts between the two?)

Yea only certain front pipes have fitment issues (i.e. ones that were developed when the car first came out), or ones like the nameless that have different versions with a Helmholtz resonator.

[drz400dude]

Originally Posted by Trust86

Ever figure out a solution with the extra coolant pipe?

I know this thread is a little old, but I just went through this myself. On the back of the engine under the intake manifold there is a coolant manifold. Right in the middle on the MT there is a blockoff plate. On the AT there is a nipple to connect a hose. I just ran a hose from the extra coolant line to this nipple. It just bypasses it back into the system. Easier than trying to pull all the stuff out to plug it.

[Trust86]

Yea turns out there are quite a few differences between the at and mt engines. I just swapped parts over from my mt engine.

[xwd]

Originally Posted by drz400dude

I know this thread is a little old, but I just went through this myself. On the back of the engine under the intake manifold there is a coolant manifold. Right in the middle on the MT there is a blockoff plate. On the AT there is a nipple to connect a hose. I just ran a hose from the extra coolant line to this nipple. It just bypasses it back into the system. Easier than trying to pull all the stuff out to plug it.

Sorry a little late, but I just cut off the pipe near the block and have a fitting over it, no issues after almost 2k miles. Ideally you would weld it shut. Pulling the pipe fitting out to plug it would be damn near impossible.

[Sportsguy83]

I've seen dozens of engines replaced, with no regard for DI numbers matching IDU, and have never seen an issue in them.

Disclaimer: it is possible there have been no issues because these swapped engines have kept their bolted on IDU but I can't confirm.

[Opie]

Dave-Ror and I just got done doing this...here are the differences that we found:

(1) Coolant crossover pipe (under intake manifold) is different as drz400dude stated above. The AT version has an extra nipple on it that connects to the Transmission oil cooler. We replaced this with a MT Coolant crossover pipe.

(2) Coolant Nipple on upper oil pan (behind the water pump) that feeds the line to the Transmission oil cooler. We plugged this with a rubber cap and clamp. Note: there are also hard coolant lines that run to this fitting that need to be removed and replaced with the parts from the MT motor for the heater core hoses.
Pic of AT lines, MT only has 1



(3) AT Vacuum Pump on the back side of the passenger head. We removed this and installed the MT cam plate. (Note: there are 2 dowel pins pressed into the AT head to align the AT vacuum pump, these have to be removed before the MT cam plate will sit flush. We used the cam plate off the bad MT motor we were replacing.


(4) Oil line that feeds the AT Vacuum Pump on right hand head, we removed this and installed the galley plug bolt out of the bad MT motor we were replacing to block off the open oil galley.

(5) AT cars use a line from the vacuum pump on the back of the passenger side cylinder head to supply vacuum to the brake booster, the MT cars use vacuum created by the intake manifold. You will need to unplug the line fitting on the intake manifold and remove the line from the vacuum pump on the AT motor, swap the line from the MT car in it's place. Note: the plug removed here makes a nice plug to block off the coolant nipple in (2) above. Just be sure to secure it with a clamp.

The MT and AT engines use the same engine wiring harnesses per model year, 2013 harnesses only fit 2013 cars, 2014 harnesses only fit 2014 cars, 2015 harnesses fit everything 2015 and newer. Note: Subaru does sell updated harnesses for the 2013 & 2014 models that require the use of the 2015+ style coil packs.

The 2013-2014 engines use different oil temperature sensors, coolant temperature sensors and coil packs than the 2015 & up engines.

The only thing to be concerned about with the DI numbers is that all 4 installed in the car are the same number (They will be #1, #2 or #3), as long as all 4 are matching you will be good. The IDU doesn't care what number they are as long as they are all the same.

[finch1750]

Most of this thread seems to relate a AT engine into an MT car. I am the opposite so wanted to post at least one bit that will save some headache.

In regards to the nipple on the upper oil pan that is missing on the MT engine, I replaced the plug in that location with this. Seems to be working fine for now and saved having to chang the oil pan and/or remove the head.

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

And you have to swap the coolant crossover under the intake manifold. While both the plug and plate are removable the MT crossover has a smaller hole for some reason and the sensor from the AT wont fit. Go figure.

[finch1750]

Originally Posted by Opie

The MT and AT engines use the same engine wiring harnesses per model year, 2013 harnesses only fit 2013 cars, 2014 harnesses only fit 2014 cars, 2015 harnesses fit everything 2015 and newer. Note: Subaru does sell updated harnesses for the 2013 & 2014 models that require the use of the 2015+ style coil packs.

The 2013-2014 engines use different oil temperature sensors, coolant temperature sensors and coil packs than the 2015 & up engines.

The only thing to be concerned about with the DI numbers is that all 4 installed in the car are the same number (They will be #1, #2 or #3), as long as all 4 are matching you will be good. The IDU doesn't care what number they are as long as they are all the same.

I know you guys have done a lot of swaps but are you 100% the harnesses are the same? I was missing at least one connector on the MT harness for the AT it looked like, unless the one I got was hacked. Plus the MT to AT transmission DIY claimed they were different.