Engine Selection For Reliability

[Djwade]

Hi all,

So i've finally set my sights on building an 818c, and I've been working through the logistics of the build and trying to really iron out the path I want to take, but I've hit a bit of a road bump with the engine selection. I've searched through a lot of the posts in the engine and transmission section, but I haven't really found the answer I was looking for in a cursory search.

First off, here are my goals: A fairly conservative build, with HP somewhere in the 225-275 range. The 818 will primarily used for weekend drives, with the occasional track day and AutoX thrown into the mix. I'd also rather have a more linear than peak-y torque curve.

The main goal for me, however, is reliability. I feel that with the power goals I want, looking for something that is very reliable isn't too tall of an order. I'm also trying to find what is the most cost effective solution. The way I see it, I have 3 main options:

1) 2002-2005 WRX donor
2) 2006-2007 WRX donor
3) 2002-2007 Impreza Donor w/ H6 Engine purchase separately.

Each of the above seem to have pros and cons. The 2002-2005 WRX is one of the cheaper all-in solutions, but if my reading as represented it properly, has a fairly peaky torque curve. The 2006-2007 WRX on the other hand is probably the most expensive option, but has more mid range torque. The H6 (EZ30D) route makes awesome noises, saves the expense of doing the water to air intercooler once on the 818, but requires an aftermarket ECU, and a custom exhaust (although that doesn't scare me all that much. I'm somewhat interested in making my own, but that's another issue altogether).

So, as I see it, all of these options will make the power I want in their stock form. The WRX options will definitely have more after market support, but also have more complexity in the form of the turbo (and more ways for things to go wrong). I'm educating myself on a lot of things related to subarus and the 818, but I feel like I need some input from people who have already gone though this process.

Any advice is appreciated.

Best,

Dan

[Canadian818]

It sounds like you've got it figured out. The 2.5 wrx would be the easiest option, but can be a bit more costly to source. IMO, if the difficulty of the build doesn't scare you then go NA on a EZ, you won't get more reliable than that. Although I'm not sure the EZ build would be any cheaper.

[Djwade]

I've been looking at every EZ build that I can find, and it seems that, for the most part, the EZ30/36 will fit right in with little modification required. Aside from the custom exhaust, is there any additional difficulty?

As far as the cost, I live in the SF Bay area in CA, and WRXs hold their value way past any and all logic. I've seen a 2006 roller with no drivetrain at all on CL for $5000+. In general, with a fair bit of hunting, I could find a 2002-2005 for ~$4000, a 2006-2007 for ~$6500, or a base impreza roller (with tranny) for ~$1000-1500 and an EZ engine for ~$1500. Factoring in ~$750 for the turbo engines needing a water to air intercooler, vs the ~$1500+ ECU for the H6, the 2002-2005 WRX and the H6 donor components will likely total around $5000, whereas the 2006-2007 will be closer to $7000.

I know those are rough calculations, and there's lots of other factors, but all are fairly similar in end cost of the donor parts, so thats why I'm considering all of them.

[redfogo]

Cheap Subaru donors are hard to get in some states that's why I just went with no donor. It was cheaper for me. But I see lots of guys on here that get killer deals unlike me haha. I vote JDM EJ207, but I also have one of those in my 818 sooo my opinion is a bit weighted lol.

[EODTech87]

Don't discount the possibility of doing a no donor build especially if local donors are really expensive. After replacing a lot of semi-wearable parts(bushings/bearings/etc.), upgrading other parts, and just wanting aftermarket parts vs stock parts I think I would have saved money and been happier with my build as a whole if I had just purchased everything separately.

I'm not saying that you should do it just saying you should look at it as a possibility.

EDIT: Damn got beat by 2 minutes.

[Hindsight]

Skip local searching and use an insurance auction site that is nationwide.

[redfogo]

Don't discount the possibility of doing a no donor build especially if local donors are really expensive. After replacing a lot of semi-wearable parts(bushings/bearings/etc.), upgrading other parts, and just wanting aftermarket parts vs stock parts I think I would have saved money and been happier with my build as a whole if I had just purchased everything separately.

I'm not saying that you should do it just saying you should look at it as a possibility.

EDIT: Damn got beat by 2 minutes.

Yep 100% agree think about what your plans are with the parts your planning to us on the car. For me I didn't wanted to spend a lot of time cleaning up old parts to look new again when it was cheaper to just buy aftermarket better newer parts. Fuel level and fuel pump assemblies are an example, most of the time they are all rusty or dirty. For me I rather just spend the money and buy newer or used cleaner ones off another car then use the ones that could have come off of a daily driven 2002 WRX from Nebraska(I looked at every single Subaru fuel assemblies in my local junk yard all where really gross looking).

[DodgyTim]

I have a AUDM EZ30 "R" from a 2006 outback (a future option for my 818R, which is starting with a 2006 EJ255)
I can read and write files to the ECU using the normal Tactrix cable, whilst I haven't updated any maps yet, I'm not convinced an aftermarket ECU is required.
the supported ecu's on the Romraider site are http://www.romraider.com/Documentation/SupportedECUs
USDM models seem to be different, with only AT models supported, however JDM seem to have both MT and AT, so a JDM front cut or engine kit may be very economical.

[Djwade]

Interesting...

I honestly hadn't really considered that. There is the advantage that local cars don't have much, if any rust, and I'm not opposed to cleaning up parts, but I'll start looking into what it might cost to source everything separately.

So that being the case, if you simply had choice of engine, is the general consensus a NA ez30/36 is going to be more reliable than a boosted ej simply due to the lack of complexity with the turbo (fewer parts to fail, etc.)? Is the oil supply an issue during cornering still or has that been solved?

And for those of you that have already completed yours, what are you running, and if you could do it again, what would you change, if anything (engine/drivetrain wise), and why?

Thank you all so much for the help, this is incredibly useful.

-Dan

[Hobby Racer]

I am building an 818R with an EZ36 and they do NOT fit right in. Because of the AVCS on the intake and exhaust cams, either the frame must be modified to allow the engine/transmission to move forward about an inch. Or you have to modify the the engine mounts to move the engine/transmission assembly back about an inch. An inch does not sound like much but there is not much room to start with and moving the whole assembly back also has transmission drive shaft angle issues that them come into play.

The only H6 option that fits right in is the lowest power version, the EZ30D first generation (the one without AVCS at all). The EZ30D second generation (often called EZ30R) has AVCS on the intake cams and suffers the same fitment issues as the EZ36.

Here is a link to the different version of the H6 on wikipedia.

As I'm sure you have already read the thread, Wayne Presley has I believe, the only completed 818 with an H6 and he used the EZ30D first gen that "drops right in".

[Djwade]

The only H6 option that fits right in is the lowest power version, the EZ30D first generation (the one without AVCS at all). The EZ30D second generation (often called EZ30R) has AVCS on the intake cams and suffers the same fitment issues as the EZ36.

Yeah, I was aware of the AVCS, but I didn't think it was that much larger. What is the main interference on the chassis? What modification would be needed to run the later gen EZ30?

I was always thinking that the first gen. would be sufficient to get to around 250 HP without much effort, is that generally true? Fairly low mileage first gen EZ30s run <$1000, so its an appealing option if I can get the power I want out of it (without sacrificing reliability, of course).

-Dan

[DSR-3]

All good points so far.
I'm in San Jose, I've fitted an EZ30R, and you're welcome to come look at it. "Stock" location, so I moved the RH frame diagonal to clear the AVCS hump. The EZ36 with it's exhaust AVCS may require more effort as the cross-member may be impacted (Hobby Racer?). Or just move it back an inch if that works for you. I think any NA option would require custom headers as even the H4 goes under the chassis (yuck). I've planned on aftermarket ECU from the start, so I can't comment on stock functionality- other than not wanting to work with the stock harness, etc...
re. SFBA donors- keep watching Craigslist. I've seen a couple very good deals since I started looking, and I sold my donor engine to a guy who got a steal on a WRX that some kids just popped. I do like the idea of no-donor, as the stripping, recovery, and replacement process/cost is not trivial.

[DSR-3]

Yeah, I was aware of the AVCS, but I didn't think it was that much larger. What is the main interference on the chassis? What modification would be needed to run the later gen EZ30?

For the EZ30R, the RH AVCS hump is the obstacle.
1. Either move the frame tube, or drill/slot the engine & trans mount points and move it back.
2. ECU solution.
3. Cooling system plumbing at the engine.
4. Custom exhaust system. *First-gen has only 1 port per side so that would be "easy".
5. The stock engine mounts are soft. I have a solution to adapt STI mounts in a different thread.

I had pictures of much of this and the process' that got "encrypted" so all are lost.

[flynntuna]

Here are some photos of the AVCS of my ez36 interference with the frame. In the photos the engine isn't in its final location the engine will need to either moved back an inch or so or frame mods and lowered 1 5/8" into the frame mount.

[Djwade]

For the EZ30R, the RH AVCS hump is the obstacle.
1. Either move the frame tube, or drill/slot the engine & trans mount points and move it back.
2. ECU solution.
3. Cooling system plumbing at the engine.
4. Custom exhaust system. *First-gen has only 1 port per side so that would be "easy".
5. The stock engine mounts are soft. I have a solution to adapt STI mounts in a different thread.

I had pictures of much of this and the process' that got "encrypted" so all are lost.

Great, Thanks for the info. Are you running boost on your EZ30R or NA? If NA, are you happy with how it is performing?

[Djwade]

Overall, I'm liking the sound of the EZ30D/R, but I'm still slightly concerned about the support for any aftermarket parts. If i do an EZ30D/R, and a few years down the road I decide that ~240Hp isn't enough, and I'd rather be closer to 300 HP, I assume the going would be more difficult than a traditional H4 build, right?

[DodgyTim]

Raptor supercharger for 200kW at the wheels (265+ kW engine) and about $5200 aussie = $3700 US
Even better you still get to keep the sound

[UnhipPopano]

So far nobody has talked about reliability and what is the reliability criteria. People do not part with reliable cars for cheep. In addition, reliability from a racing standpoint is different from a street car. The most reliable is where a crate or rebuilt engine is purchased. If you are going to spend that much on the engine and transmission, how much more is it over the life of the car to purchase new parts?

[Hindsight]

In addition, reliability from a racing standpoint is different from a street car.

This.

The main issues subie engines have is cracked ring-lands from detonation, and oiling issues under high g-load cornering.

So far, no one has proven what is the real cause of the cracked ring lands but there is a lot of speculation and theories and most of them make sense and can be easily addressed:
1. Bad tune (too much timing, too lean, etc)
2. Oil in the intake system reducing octane rating (fix with an oil catch can or air oil separator)
3. Cast pistons used by the factory
4. Too high intake temps

As for the oiling issues, some years had an oil pickup tube that was known to crack and prevent oil from being drawn into the pump. The STI and later model WRXs had a better, deeper oil pan as well. The horizontally opposed engine layout causes oil to rush into the cylinder heads under heavy cornering. If you are going to run street tires, and stay on the street with the occasional auto-x and road racing track day (on street tires), my suggestion would be to use the big oil pan, a killer-b oil pickup and killer-b oil pan baffle.

For max reliability, aside form oiling recommendations above, start out with a new short block with forged pistons (many tuners offer this as a "stage 1 short block"). Ensure you have a GOOD tune. Monitor your intake air temps and ensure they stay as low as possible (preferably below 125 - need a good intercooler setup). Running E85 will increase both power and engine longevity. Use a new high quality fuel pump to avoid fuel starvation issues. Have injectors flow tested or replace them. Use all new fuel lines and fittings. Ensure your vacuum hoses (especially those connected to the wastegate) could never melt or come loose).

[Djwade]

So far nobody has talked about reliability and what is the reliability criteria. People do not part with reliable cars for cheep. In addition, reliability from a racing standpoint is different from a street car. The most reliable is where a crate or rebuilt engine is purchased. If you are going to spend that much on the engine and transmission, how much more is it over the life of the car to purchase new parts?

This is a good point, and one that I had been counting on, but failed to mention it in my posts. Regardless of what engine I choose, The engine will be rebuilt. If I'm going to go through all the effort of building this car up, I want as fresh an engine as I can manage put into it. The question of reliability that I'm pursuing is operating on the assumption that each engine has been gone through and rebuilt properly.

[Djwade]

This.
For max reliability, aside form oiling recommendations above, start out with a new short block with forged pistons (many tuners offer this as a "stage 1 short block"). Ensure you have a GOOD tune. Monitor your intake air temps and ensure they stay as low as possible (preferably below 125 - need a good intercooler setup). Running E85 will increase both power and engine longevity. Use a new high quality fuel pump to avoid fuel starvation issues. Have injectors flow tested or replace them. Use all new fuel lines and fittings. Ensure your vacuum hoses (especially those connected to the wastegate) could never melt or come loose).

Regarding the short block with forged pistons, do said pistons present any advantage if I'm not running much higher power than stock? If I recall correctly, forged pistons tend to actually be smaller than the stock pistons (on purpose) and will increase wear as you will get piston slap until the engine comes to temp, as well as more blow-back on a cold engine. This is a lot of internet hearsay, however, so please correct me if I'm mistaken on that point.

So back on the subject of reliability, assuming that I'm starting with a fresh rebuild, and running near stock power, would an EJ25 ultimately be more reliable with the occasional AutoX or Track day because there are aftermarket solutions available for the oil issue? (preliminary search yielded no baffled oil pans for the EZ platform)

[Hindsight]

I am no expert at all, so take this for what you paid for it, but I have not read of much success in racing with the 6cyl Subaru engines. Oil issues mostly. No dry sump available yet. Been discussed here a small bit.

At 275 to 300WHP, the EJ series engine should be plenty reliable assuming you take care of the items I mentioned in my post above.

Yes you are right about the forged pistons but I personally wouldn't be concerned about the two issues you mentioned. Piston slap, if it's not terrible, generally isn't that big of an issue. I have a 23 year old VW 5cyl that has almost 200k on the original engine, burns only half a quart of oil every 5k miles, and has had piston slap on cold start since it was brand new - still drives and runs great. If you have a good oil catch can or AOS, a small amount of increased blow-by on a cold engine shouldn't cause any issues.

[Djwade]

Well, given the above information, especially regarding the lack of parts available for the EZ30 and the oil issues inherent, I feel that pushes me towards an EJ engine. I realize that may come off as overly cautious, as I'm not likely to ever be driving hard enough to see the lack of a baffled oil pan cause issues, but I think it's just something I'd rather have a solution for, even if the problem never occurs.

So that being the case, It seems i'm likely looking at either an EJ255 or and EJ205. Is there any reason to inherently go one way or the other? Instinctively I'd rather go for the 2.5 to get more mid-range torque, but if the 2.0L is more reliable, and there are ways to level out the power curve (slightly smaller turbo?), and still keep ~225+ HP, I'm open to that option.

[UnhipPopano]

If you are more concerned about reliability and maintainability, perhaps you should consider a NA engine.

[305mouse]

between the two turbo options I would go to the 2.5, more low end torque. But as stated above, consider the N/A 2.5 engine. Less parts, lower power but with the weight it'll still be a blast to drive.

[iblackwe]

I actually find it comical for when everyone tends to think Subaru engines are unreliable. The only reason you find people with major issues is when it is modified from a stock stand point and driven pretty hard or raced. There are cases of defects that's for sure but most cases involve modification to the motor, blowing the transmission because of too much power or cracking ring lands because of too much boost pressure.

The donor I chose was a bone stock 2003 WRX ej205 that the guy had babied until it was damaged in a hail storm. It had 280k km's on the clock and it ran great! I ended up rebuilding it for fun with the same goal of reliability. When I took it apart I was surprised to see it had very little wear to the cylinder walls and the leak down test had proved the heads were in good condition.

So from my perspective if you are staying within the stock realm of things and not putting any performance mods into the car you will likely be fine with any turbo or non turbo option you chose.

If your aiming for increased reliability like I was I had the turbo rebuilt, put Mahle 4032 forged pistons (an alloy that is almost as quiet as stock and you can hone for the same tolerances as stock) and rods/ crank. Had the heads refurbished (seats ground and new valves). Also installed an oil catch can system, an AWIC, and an aquamist water meth system for the sole purpose of keeping the intake temperatures down as the engine bay gets very hot in the 818. New fuel lines and fuel pressure regulator, and new injectors. I am on the verge of getting ready to tuned it as well to make sure everything lines up and is good to go. For an idea of cost it is around the $6500 CDN mark right now. Having said that, if I were to do it all again I would get an IAG stage 1+ or stage 2 block as the machining costs for the original block were more than what they sell their packages for.

My $0.02.

[alpine227]

Overall, I'm liking the sound of the EZ30D/R, but I'm still slightly concerned about the support for any aftermarket parts. If i do an EZ30D/R, and a few years down the road I decide that ~240Hp isn't enough, and I'd rather be closer to 300 HP, I assume the going would be more difficult than a traditional H4 build, right?

Supertech Has forged low compression pistons, valves, valve springs and retainers, few companies have rods and for this looking for foolish levels can get a fully closed deck case from out front. There seem to be several ecu options working with native 36-2-2-2 wheels Hydra, halted, ms3. The issue I am working on is fuel injectors. The ez30d has air assist injectorswhich are a bit wonky. i swapped the air assist caps onto some de capped blue wrx injectors need to check the spray pattern and probably cut down the rail mounting tab a few millimeters as they are shorter than the ez30d injectors. Not sure if Wayne tried recapping the stockers to see what they can flow.

[mikeinatlanta]

Don't have an 818, but did have an 02 WRX. We beat the crap out of that car for 100,000 before selling and it was bulletproof (all stock), so most certainly more than reliable enough for the 818. IMO, the peaky torque thing is overstated.

[DSR-3]

I just stumbled across this. 'looks interesting and like it would be a clean install, but no doubt spendy... daily-Dry_Sump1.jpg
http://www.daileyengineering.com/dry_sump_oil_pans.htm

[Sgt.Gator]

I just stumbled across this. 'looks interesting and like it would be a clean install, but no doubt spendy... daily-Dry_Sump1.jpg
http://www.daileyengineering.com/dry_sump_oil_pans.htm

At the min the Dailey needs custom headers.
Dailey SUBARU INSTALLED 4.jpg

[JB91710]

I just found out the electronics to run my engines with Motec is going to cost a whole lot of money.