EZ30 into EJ25 Outback?

Hey everyone.

Since fitting larger tyres to my OB, its just lost all its zing. Permanent weight has increased too which hasnt helped.. Its too slow!! Ive looked at turbo EJ's and they're too complex for my liking. Three times the amount of hoses etc. I use my OB for touring and go bush often so reliability is paramount. Less stuff to go wrong is choice. Lack of torque sucks! And i may need to tow a fair bit (small caravan, heavy trailers) in the future.

Which leads me to the H6. More guts than a gt foz without the extra turbo stuff, a lot more power and torque than the ej25. Probably will use the same amount of fuel because to tow (or get through soft sand or move quickly across an intersection) as is it needs to be revved hard. The H6 will drop into my OB's engine bay but my question is what needs to be changed if i eventually may go down this road?

Ecu plus complete wiring looms?
Does it bolt up to the manual gearbox?

Ive modded my OB enough to make the H6 swap easier than buying a factory fitted H6 OB and swapping bits over. Besides, its been verrrry reliable so far (hence not rushing into any engine swaps till i need it.)

Probably a lot of effort id imagine.

Cheers!

it'll bolt straight in - some quick research suggests you need a TT gearbox crossmember to clear the exhaust.

You'll need the H6 ECU, as for wiring, you'll either need to swap the engine+bulkhead harness or re-wire bits of it (for 6 vs. 4 injectors and ignition if nothing else). I'm pretty sure the ECU just needs a pin pulled to 12V or GND (neutral switch).

Given A&M in Brisbane a call - they'll be able to tell you about the wiring situation and can do a harness for you if required.

I'd also consider the full H6 + Auto swap.
the auto is good off-road, and beef it up with an external oil cooler will keep it happy when towing. and you don;t burn out a clutch when pulling heavy-stuff around

TheInterceptor said:

Hey everyone.
Ive modded my OB enough to make the H6 swap easier than buying a factory fitted H6 OB and swapping bits over.

Click to expand...

mmm... be careful here, too.

Engine/wiring swap isn't difficult, but engine/bulkhead wiring changes typically require the complete dash and HVAC out.

Ask me how I know.

I tend to agree with Duncan ...

Buy for purpose, then modify to 'tweak'.
Making a silk purse out of a sow's ear is rarely satisfactory in the long term.

Do your sums carefully, and think about it carefully. Then decide.

Second option,
buy a H6 outback, swap all your good bits,
Sell the 2.5

Maybe we're all being a bit negative..

I love the engine swap I've done on my outback, and from what I've read, a manual H6 is a real weapon (foz, liberty or outback).

If an H6 manual is really what you want, and you can do the mechanicals and harness swap yourself, I say go for it.

My swap was a similar level of complexity (maybe more, given its a twin turbo, so it has even more plumbing than a typical single-turbo swap) - and it wasn't actually difficult.

You just need some time to work through all the pieces of the puzzle, and a good workspace.

I have an EZ30 in my foz from a GenIV outback. Your OB looks like a GenIV, so you may not have to go the aftermarket ECU route. I would ask AM Auto about this.

The reason mine has an aftermarket ECU is that you need to establish CAN communication with other control modules: It couldn't be done with the Forester, but I can't imagine that modules in a Gen IV would differ from 2.5 litre to 3.0 litre. I could be wrong, but it is well worth asking.

If you can go the factory 3.0 litre ECU route, then that would save a fair bit of mucking around and expense.

In the short term, reset the ECU. there is a thread on that somewhere, but it involves disconnecting the battery.

His is a Gen3 OBK
so it's literally plug n play with the early motor

Thanks for the replies everyone.

I dont mind the idea of the auto but i prefer manual for the time being. I prefer manual for this vehicle for a number of reasons.

Duncanm, im intrigued by the splicing into the current wiring. Being the H6, it would require its own ECU and associated 6 cyl bits. However, mine being the Limited model with all the mod cons of an ej25 equipped vehicle, it shouldn't need any other mods for climate control etc etc. Just engine managment. Not even a TCM because its staying manual. (Dulagarl, you would be correct in saying the modules are the same)
Currently i cannot do large jobs where i currently live however i may be moving to Perth in a few months which will allow me to do this.

Sounds like i should give AM Auto a call. If they can do a loom that taps into the EJ harness then thatd be the way to go. If the dash has to come out, not ideal but it'd be an opportunity to hit the hidden areas and cavities with some cavity wax, just for protection.

Robbks, i have thought about buying a new vehicle but this one is way too good and has had too many mods to warrant starting over.

Dulagarl, battery reset hasn't done anything performance wise. Ive reset it a few times since fitting the dual battery kit to no avail.

Ratbag, this is currently just a speculation thread...see whats involved, see if its worth it. Im thinking it would be. As is, towing a 5x7 cage trailer with a few things in it see's me go from 100kph to 80kph in the space of a single hill. Feels like my old L series! Even without the trailer, it just dies in the arse on hills. Needs to stay above 3500rpm to make it boogie. Fast take offs dont exist. But i suppose that is kind of what happens with 215/70r16 (28") tyres.

.... If you are towing, do you need fast take offs? Having just towed 1100kms with the car loaded to the gunnels and a moderately loaded 7x5 trailer I did not experience loss of power to the extent you describe. Do you really love the tyres?

Best regards,

Nope. But when im not towing, im a hoon at times and like racing people. So far ive lost to every vehicle except a diesel 3t truck

Tyres increase my total lift and ground contact patch. This car does a heck of a lot of offroad work every week (it looks similar to my avatar pic most of the time, shortest time it stayed clean was 2hrs!). I go touring every so often too. A few months ago i clocked up 14,000kms from here to Syd and as far north as Bundaberg QLD, with offroad excursions included.
Its there for a purpose, like every part of my vehicle, every mod is there for a good reason.
Like i said...this is a speculation thread. Theres still a good chance ill stay with the 2.5 till it dies (cos its been reliable as) then put an EZ30 in.

I'd try get a wrecked gen 3 h6 / front cut. Swap the entire wiring harness, the nicer cluster, etc etc. everything else should plug in and go.

I still think you'd be better off buying a good H6 car and transferring your mods IMO. Look at it this way.

A conversion is going to cost you multiple thousands of dollars. If your lucky 2-3k, 5k+ if things go wrong. You wouldn't believe how much the costs can quickly add up. Then your looking at at least 3 - 4 days solid to do the conversion depending on equipment and skill level. Maybe more with issues.
Then consider the potential issues with getting the car legalized as a H6.

Then there's the fact that a conversion will never, ever be as reliable as a factory setup IMO. And reliability is obviously very important for you.

Will swapping your mods take so much time/ effort that the costs and potential issues of a conversion STILL appear as the better option?

Believe me I have been through the outback conversion (albeit a significantly more complex conversion) and yes it is bloody awesome (I don't regret it even though it was a financial disaster, the experience and learning I gained was incredible).
I think conversions should only be considered when a factory equivalent does not exist.

Either way good luck whichever route you choose, hopefully you end up with the offroad beast you are looking for. :biggrin:

Then there's the fact that a conversion will never, ever be as reliable as a factory setup IMO. And reliability is obviously very important for you

Ditto. If you love the reliability of your car, changing engines is costly but changing size and specs is more headache than I would care to contemplate. When I was young and foolish... Dare I say it .... Even hoonish... I messed with a V8 HZ. The car was never the same again, and cost wise I probably could have had shares in Holden.

That's why I love the car I have now. It's probably the only reason I still have my license!

Best regards ,

I have a whole gen 3 outback with motor and loom if your interested.
Txt me.... :iconwink:

Change your final drive ratio of your gearbox to 4.44 and you'll gain your zippyness back... I wish I had done with my custom box. I certainly feel your pain.
I'm looking into raptor supercharging as an option.

This is very true about conversions and reliability. While I may own more than 5 cars, most are ****** due to conversion issues of sorts.

That doesn't sound right with your EJ25, I remember pulling away from you in my ****** ej22 AWD L-Series which was much slower than my Forester(that being slow fullstop). When I come down your way next I'll take a look at it. Could have a few small issues, should have much more torque than that. Mine only dies in the arse like that if I have a car trailer with car on the back. However in 4th it maintains 100km/hr. Given this is more than double what the Forester is designed to tow(2.5+ tonne lol).

If your dead set on a H6 conversion then sell the car and buy one factory with a H6. Not worth the ******* around! I'm Speaking from experience here..
If you do a conversion however no point going a gen 3 h6. You'll soon find that doesn't have enough power too(how I am with my worked EJ25). They don't put out much more power than my built ej25. Then gen 4 H6 EZ30R is a much better motor.

Can you do a quick list of all the mods your car already has? Remember that "a conversion" is a name for probably 100+ individual mods to get the end result. If you really think about it, it probably will end up being cheaper, easier, and ultimately a more reliable outcome to just re-mod a factory H6 car. Although I'm happy to stand corrected - please list your mods

I'm not sure why people are saying a conversion will be unreliable... but you should consider the option of dropping your mods and a manual gearbox into an H6.

Its all OEM parts - if anything, you'll have the car in pieces and will have a chance to renew all those things that need replacing that you've been putting off - like engine and gearbox mounts, timing belts, clutch, rubber hoses (brake, clutch), coolant hoses, water pumps, cam cover seals, etc etc.

Check out subyclub.com - there's a couple of H6 conversions kicking around there eg: this outback, and a really nice GT30 inspired liberty with an EZ30D conversion.

As for wiring harnesses - if the H6 harness doesn't drop straight in (it should, if you pick the donor to be same same rev (A-C or D) as your victim), A&M can splice the two engine harnesses so your H6 with ECU will plug straight in.

I totally agree, you would be much better off buying a factory H6 OB and swapping over whatever customisation onto it. You'll come out ahead. It will be cheaper, more reliable, more satisfactory, etc.

If you go a H6 conversion, expect there to be a lot of bugs to sort out & many hidden expenses.

You play, you pay :rotfl:

Scooby2 said:

Then there's the fact that a conversion will never, ever be as reliable as a factory setup IMO. And reliability is obviously very important for you

Click to expand...

That's only an opinion and that's also said in this statement. My L series is modified yet I've had less issues than when it was an EA82. Worn components will always be an issue in any vehicle.

The wiring will be the biggest job or the biggest cost, either way get that done properly and you'll be sorted.

If your model of outback came from the factory with the H6 it should be pretty straight forward overall. Get the wiring done then use factory components where possible and you'll be sorted. H6 + manual = awesome. Do look into the jerking issue that Venom has experienced.

But again, as Taza has wisely said, do a diff ratio change and you'll have your zippiness back again with the EJ25. While you've got the box open it's a good chance to drop a front LSD in which is well worth the effort and coin involved!

Cheers

Bennie

This is the fundamental problem: the more you change the more variables you need to account for if something goes wrong or starts playing up. That is not less reliable, it is more complicated. Of you have something you can't fix or solve, who do you take it to? Most mechanics can't handle a car with an engine conversion. It's too complicated for them. Even Subaru mechanics are only familiar with the 4 bangers and turbo conversions.

Personally i don't like the manual conversion on the early H6. It never idles smooth and has an intermittent stalling issue. It's a 16bit ecu so you can't tune it. All the renewable parts like sensor are ****ing expensive because they never sold many. The iridium plugs are $30 EACH. That's $180 in spark plugs. It will have 3 ECU codes from the manual transmission you can never get rid of. Even though it's NA you're actually making the car more complicated than a turbo vehicle.

The later H6s came in manual but its a CANBUS ecu and you need an aftermarket ecu to run it. Say goodbye to $5,000 minimum there.

Its a great motor, it's a beast with a manual. The only way i would do it again is with an aftermarket ECU and it's not worth the money to do it.

Or i would buy a factory H6 car and put a 4.44 auto behind it and use the VDC centre differential from the H6s auto.

Your problem is gearing because you have put on bigger tyres, not a lack of power and torque.