total noob with boxer engine
 

so im super excited about this car and i love that its using a subaru engine, but i have no knowledge of these engines. i would love it if someone with a boxer engine would answer some questions i have b4 i plop some money down for this car.

1.how reliable are these engines, and what are the problem areas?(i know subaru has a whole ad campaign about how reliable their cars are but what are the gremlins)

2.how easy are they to work on? my first car was a v8 camaro and i loved wrenching on that thing it was so simple and easy to do repairs i would hope sometimes that it would break just so i could fix something

3.what are basic mods that would not void the warranty and how much power do they add (on a subie)? ie like exhaust and intake

4. being that this car has a high compersion ratio how safe is it to turbo, supercharge, or even nitrous?

i would love answers to these questions thanks in advance.

While these are all valid questions, they have all been answered in excruciating detail in other threads, or we simply don't know the answer yet because nobody has been able to test this engine (at least been able to test and share results). Prepare your anus for the deluge of search button hate.

It's basically the same as every other modern engine, except the cylinder heads are somewhere else and tougher to access. The exhaust is solely accessible from the underside of the car, and the intake solely accessible from the topside of the car.

It's impossible to give exact reliability information as this engine model is brand new. Barring something quirky/stupid, the engine will be totally reliable in normal street use.

Regarding boost, this isn't an easy answer due to the complicated direct injection combustion strategies, however a very rough estimate would be less than 8 pounds of boost with intercooled intake charge on 93 octane. This is of course assuming you have competent control over fuel, spark, and cam phasing. Obviously it's much more complicated than that in reality. It's your engine, grenade it as you please.

1. a Boxer engine is fairly reliable; partly because it has good primary balance and excelent secondary balance. This engine in particular is likely more reliable than some other direct injected engines because it also uses port injection which will help keep the intake valves clean.

2. It should be fairly simple to repair, as it uses ODB II which should aide in diagnostics if you have a reader. However since it is a boxer engine things like spark plug changes, and head gasket replacement will be a bit of a pain in the bottom. At the same time since the engine basically sits on top of the front crossmember and the exhaust ports are on the bottom putting on an exhaust header might be a bit of a pain as well, however the factory exhaust header LOOKS to be pretty decent.

3. They would be the same as on other vehicles, though changing the distance of the catalytic converters from the engine might make it not pass inspection, specifically moving them farther away from the engine.

4.The higher compression ratio just limits the the amount of forced induction you can have, not necessarily the desired ultimate power output of the engine. This means that for say 250hp an engine with a higher compression ratio would use a lower boost pressure. Basically the decider on how much hp you can make out of a given engine is the ultimate pressure ratio (similar to the compression ratio but not the same thing), and the temprature of the combustables (oxygen and fuel) at their ultimate point (which happens just after Top Dead Center during the combustion process), and the fuels resistance to detonation. So the quick answer is it will still be safe to add forced induction or nitrous, just at lower levels than what you would use on a engine with a lower compression ratio.

I'm glad to hear that's it's a pretty simple engine and the maintenance isn't as complicated as an rs8 rotary engine. By looking at the pictures of the engine compartment it looks like u have access to the alternator and serpentine belt system with no problem. Now the only other question that I have is if it's going to be a timing belt or chain

Hks has already SC the engine and got 250 I believe. Thers a picture of it on these boards somewhere.

It's a timing chain. One of the general maintenance items that might be a pain is the spark plugs. Some people have said that you will have to remove the fender liners to get to them. As far as inherent weaknesses in a boxer engine go, since the pistons are on their side the bottom of the cylinder sees more friction at start-up than in a V or I engine. But, from what I've heard modern coatings have pretty much alleviated this.

How do you figure that?

*that Boxer cylinder bottoms see more friction

Gravity?


Im not defending that claim since I dont know much about boxer engines either.

Considering that the bearings see several thousand g regularly, the skirts sometimes see over a thousand g, the extra weight on the side of the piston doesn't mean much at all, I would think.

4 cylinder boxer engines have better balance than any other 4 cylinder layout (although not perfect balance like a flat 6 or inline 6). I have only driven a boxer 4 once and I was impressed with how smooth it felt considering the harsh noise it made. Better balance in theory means better reliability. However, It does have two sets of camshafts which means more weight and potentially less reliablity.

But overall this car (like many new cars) will need minimal maintenance. You have one serpentine belt you have to replace and two radiator hoses. You need only change engine oil, oil filter, fuel filter, transmission oil, differential oil, coolant, and brake/clutch fluid. The Denso iridium spark plugs should be good for about 100-120k miles so that's not something you'll have to regularly worry about - which is good because it's harder to access the spark plugs in boxer engines compared to inline engines.

I also like how this car will have underbody panels covering the engine so that little to no water/salt/crap will kick up into the engine bay. It also has a small frontal opening with a gate in front of the radiator and the radiator is tilted which helps minimize stuff getting into the engine bay which means less wear on components.

This car will perform consistantly for a very long time with minimal maintenance costs - unlike my AWD turbo Eclipse which has had to have nearly everything replaced recently.

The fact that it is direct injection/high compression will make it harder to tune for a turbo. I wouldn't do it unless you really know what you're doing and don't care about lower reliability.

The rings act as springs (for the most part) and put an equal load all the way around the cylinder.

i dont know how much gravity will change the wear but i dont think that you can say that

I will have to look up where I saw it, but i read that boxer engines see more wear at start up due to inherent lubrication issues. Of course I read it on the internet, and they say that 75% of things on the internet are made up.