n00b question: 2.5 turbo vs H6

[Superu264]

searched already on LGT.com but didn't find anything

What is the point of the 2.5 vs the H6? The H6 has 2 more hp but its rated at 215 lb-ft (4200rpm) whereas the 2.5 is at 241 lb-ft. (3600rpm).

Is it just the fact that the H6 power is ready all the time and the 2.5 must have the turbo working? The most torque in the H6 comes later? What am I missing?

[Jedi Taxi]

meh, i dunno. They both have good output and all. but seriously, niether of them are that reliable. To me, its either the 1.8L (impreza) 2.0L or the 2.2L and then building them up to insanity. Im not saying the 2.5L is horrible, it too requires some work. Where as the 1.8L, 2.0L, and 2.2L require work (turbo and a good build up) for power. The 2.5L requires block work for reliability. so really, choose your poison.

[Superu264]

I'm not building anything or have a project going, this is just something that was bothering me.

[AJM]

The 3.0 is really more of a suv engine, and it's not worth swaping unless you can get it for extremely cheap.

The 2.5 turbo is much better performance wise. See, you're better off witth the torque at the lower part of the power band...hence why the 2.5 is a performance engine, with more torque at a lower rpm, whereas the 3.0 is more of a ho hum upper class sedan motor. (think 2.5 gt as bigger wrx, think 3.0 as camry fighter)

[Jedi Taxi]

on top of that, the 3.0L has reliability issues, and its power doesn't make up for its weight. now i must admit i haven't a clue about the tribeca 3.3L. Generally, i stay way from subaru H6's. its like having a RX7 and putting in a iron block 350 LT1 chevy motor, minus the awesome power. so basically, you get some power and alot of weight. IMHO, this equates to NOT WORTH IT.

[Huffer]

Lina Racing disagrees with you... the point of the H6 engine is reliable power delivered in a linear fashion. No extra oil cooling lines, no turbo to blow up, and no wastegate to get stuck open.

http://www.linaracing.com/impreza-h6-conversion-faq.php
Some links are down, but that rally crew is arguably the first to put a 3.0L into a 1.8L Impreza chassis and rally it on all surfaces.

[Jedi Taxi]

well, like i say to everyone else. "If it works for ya, then props to ya." I only question there reliability. I dont question that they make good power. Granted the new H6s and the old H6s are different types of motors, to mistake that is whorendous. bascially, the new ones could be reliable and powerful and i would be ignorant of it. Not that i wouldn't be happy to learn about it, because i might look into it. I am just going to say that i am baised towards the H4s.

[edit:]made it easier to understand.

[Wiscon_Mark]

Jedi Taxi, I have no idea where you are getting your crack, but I'd like some :lol:

The EZ30 and the EJ255/257 are unreliable? You know Subaru made CR's "most reliable automaker" last year, right? The N/A EJ25 had headgasket issues, but I've never heard anything terribly major wrong with the LGT, WRX, STi, Tribeca, or Outback's motors. Granted, turbo owners will run into problems more but you have to look at who buys them and how they're driven. There are many WRX and STi owners pushing over 100k with very few or no issues.

If you're thinking H6 and unreliable, I think you're talking about the EG33 on the SVX. Oh, and the Tribeca has only ever had the EZ30, they never had a 3.3L. And I'm not sure what this extra weight is that you speak of. The EZ30 is barely heavier than the EJ25 - it has about the same dimensions as any other EJ series engine (as it was designed for the Legacy). The extra weight must be the fact that it was put in the Tribeca, which has a lot of extra luxury, safety, and sheetmetal. The engine did not make it 4200lbs. You'd find it has a bit more pep in the lighter Legacy (~3400 lbs on the LL. bean, IIRC).

The advantage to the H6 over the turbo 4 in the Outback and Tribeca (read: Subaru's luxury department) is that they provide very smooth linear power that is well delivered through an automatic transmission (something most people at that price point want) than the somewhat peaky turbo 4. The H6 used to get a better torque rating, but it really dropped when the new SAE ratings came out...I'm not really sure why.

[AJM]

Consumer reports? Come on...

As far as the different engines

"This flat-four DOHC boxer engine churns out 250 lb-ft of torque at 3600 rpm - significantly more than the 219 lb-ft of twist created by the 3.0L engine. Beyond stimulating output, this engine also boasts Subaru's latest powertrain technology. For example, volumetric efficiency is aided by AVCS variable valve timing technology that adjusts intake camshaft timing to optimize intake and exhaust valve actuation, helping to balance power, fuel economy, and emissions. Its air-to-air intercooler is both smaller and 13-percent more efficient than those on other Subaru models. While the trend in spark plug technology has been to favor platinum for performance and longevity, the Legacy goes even further with iridium tips for improved efficiency. Investment was also made in weight reduction, with this engine being significantly lighter than similar applications in other Subaru models without reducing its strength. For example, the cams alone weigh 8.8 pounds less than those in the 2.5L Forester and Baja models. The end result is a powertrain that promises 5.8-second 0-60-mph time, according to official factory numbers. We suspect another tenth or two could be shaved off that conservative estimate, putting this car squarely in musclecar territory.

From behind the wheel, the 2.5L and 3.0L engines are on target for their intended buyer, but our automotive passion clearly draws us to the turbo 2.5L model. This is exactly what Subaru hopes as it now offers a compelling step-up model for its Impreza WRX owners and an attractive lure for consumers accustomed to more mundane family sedans and wagons, and perhaps even draw shoppers away from near-lux models with its value story."-MT


Basically Jedi taxi's problem with ej25's is...I'm not 100% sure on this, but I've heard the block flaw still exisits in most ej25's today. However, Subaru put MLS head gaskets and torqued them down tighter than before. Even if it is true, then simply Subaru put a band aide over the problem. Does it really matter? It seems to be working...

[AJM]

The H6 used to get a better torque rating, but it really dropped when the new SAE ratings came out...I'm not really sure why.

This one is easy, the old measurements used by the SAE pretty much hyped up every motor, but espially forien motors. When the new ratings came out, alot of U.S. Mau gain hp and tq , wile japanses manu seemed to loose alot. However, I have been assured by meany people that this new system of rating is acctully much more accurate.

[overl0ad]

my 2 cents:

if u want "bash eyeballs into skull" go the turbo.

if you want linear power, go the h6.

you really to have driven or been driven in both to understand the difference.

if u wanna REALLY go over the top, go the H6, then turbo it :D

quiate a few people in aus have done it successfully and i suspect that you can even come very close to buying a kit for it.

[Wiscon_Mark]

Consumer reports? Come on...

Huh? I didn't say anything about their test drives or performance ratings, they definitely don't apply to auto enthusiasts. But if there is something I look at, it's their comprehensive reliability ratings, they're very good. Again, to be taken with a grain of salt, but the trends are generally true and accurate.

[deadlydave]

The old EZ33 had some cojones, but the weight penalty associated with it was considered by some not worth it. In swapped imprezas especially, having that much weight up front totally borked the handling. Kinda like the 289 shelby cobra and the 427 shelby cobra--linear acceleration was improved at the expense of handling.

I think overl0adhit the nail on the head, good job man.

Does anyone know if the H6 is better on gas than the 2.5L turbos?

[Wiscon_Mark]

They're about the same in normal driving, the turbo is better if you stay out of boost.

It's EG33, not EZ33. The EZ retains EJ dimensions, the EG was a much larger engine, hence the extra weight.

[dodik]

H6 is very smooth. so far i owned it for only 3 month with absolutely no issues and if you do cold air and take out valve spring in a muffler it goes way quicker thru rpms and makes it more fun to drive. mpg is a little better than my old ej25 with 273k on it but very close to it. i average 20 mpg 50/50. having test drive all subaru models i found this one is more suitable for me. car is more luxury has winter package, beige leather all around decent stereo climate control. engine wise im just tired of 4 bangers so h6 was the way to go. plus i need that extra high sidewall driving in NYC.

[Jedi Taxi]

wiscon mark....im not gonna start on you man. I said myself that i dont know much about the H6s, And that proves it! i didnt even know which H6 went with what. Even if the 3.0L H6 is barely heavier than the 2.5L It is still heavier non the less. Personally, the 2.5L being the heaviest of the EJs, because of this, (and its need of block work to run lots of boost) i wouldnt use it. I like handling more than power. Either way, get off my ass.

[Huffer]

People watch the attitude in this thread... we will not have the tech section degenerating into a "I heard this vs. that" section.

[AJM]

It's really not that big of a deal. I just prefur more all out performance personally, to dive an auto is like to take the cars soul away...

It sort of has turned into "My God has a bigger d*** than your god" thread. Maybe it's really just a matter of personal pref.

I go more by personal experinces, thats why I don't like CR. Personally I know people who have put 3 engines in thier neons etc and still say they love them to death and would rate them high. The genral puplic isn't that smart sometimes. Unless your talking about intial quality in CR, in which case their opinion might be ok because thats written by editors.


That's how I feel about alot of information on here. I feel alot of it is just reguritated from nabisco, or some other place ,and few people are actually willing to go and take apart an engine at a junk yard to learn why this doesn't work, or this does.

I'd like to state I haven't done any name calling hahaha :lol:

[Jedi Taxi]

+1 huffer and AJM.

[Wiscon_Mark]

Dude, I'm not one to sport attitude, but when you start spreading misinformation around, I'm going to cut through the BS in a way that will get your attention. Please don't take it the wrong way, I didn't mean anything by that crack comment, it was in jest. But I find it important to grab people's attention when they're off base and don't know it.

Consumer Reports doesn't just use consumer surveys, they also take shop records and dealership records into account. And they do separate reliability and customer satisfaction into two different categories. Their reliablity records are the best out there. Initial quality is kind of a bunk category as it's based entirely on opinion, and not on cold hard facts. I don't know how you can argue with service records.

[Jedi Taxi]

LISTEN man, I woke up... WITH A CLOWNS hand...in my PANTS....Thats pretty much where im at right now. also, get off your high horse, its just a forum my friend. Lies are told all over the place. The hardest part is destinguishing fact from fiction. I will tell what personal experiences i've had, and you can tell what service records say. Now through the combination or our information, we can deside what is fact. what do ya say? truce?

[Superu264]

what the hell happened

I didn't know I was starting a war :lol:

[rougeben83]

Ok ok ok ladies :) Bottom line is this, the H6 is there as a refinement option for people that don't need the "ZOMG BOOST" and just want a semi-luxurious car to comfortably drive around in (read, camry's, accords, and with the latest move for Subaru to upscale the Legacy line w/ the 3.0r, infiniti's, C-class mercs, and BMW 3-series).

The turbo engine is there for the hooligans among us that want that shove in the back when the turbo spools, and/or the ability to see more power via the aftermarket.:grin:

They both use the same base, but the way they are being marketed (I think appropriately so) by subaru is towards 2 different types of car audiences.

[AJM]

Ok ok ok ladies :) Bottom line is this, the H6 is there as a refinement option for people that don't need the "ZOMG BOOST" and just want a semi-luxurious car to comfortably drive around in (read, camry's, accords, and with the latest move for Subaru to upscale the Legacy line w/ the 3.0r, infiniti's, C-class mercs, and BMW 3-series).

The turbo engine is there for the hooligans among us that want that shove in the back when the turbo spools, and/or the ability to see more power via the aftermarket.:grin:

They both use the same base, but the way they are being marketed (I think appropriately so) by subaru is towards 2 different types of car audiences.


I agree. :grin: +1 I'm a hooligan!

[Wiscon_Mark]

what do ya say? truce?

Deal, dude, I wasn't trying to start anything in the first place. Just clearing things up.

I think i'm turning into Ooberdoob.