Engine Mods

[Neil '01]

So, it seems that no one is in favor of turbo charging my 2001 Legacy Outback. I looked in to changing out the bottom end to a stronger block, but that seems to expensive and laborious. Does anyone know how much usable power can be gained from new cams and exhaust? The car is used mainly for around town and trips to Lake Tahoe. Would like to have more power in the mountains, but I don't want to rev the engine at 6000 rpm for 2 hours to use it. Any thoughts?

 

I already put a cold air intake on the car because of damage to the stock intake. I was looking at the Impreza power package from Cobb, but doubt that the exhaust pieces will fit. Maybe the equal length headers will fit. Any feedback would be helpful.

 

Also, does anyone know a good shop in the San Francisco Bay Area that is reputable?

 

 

Neil ‘01

[erik litchy]

its too bad you couldnt swap in a used turbo engine, because thats just where turbo engines shine, is high alitiudes. you could install a more free flowing tuned exhaust, but its not going to be a huge diffrence. cams, well that depends entirely on the grind.

[hklaine]

its too bad you couldnt swap in a used turbo engine, because thats just where turbo engines shine, is high alitiudes. you could install a more free flowing tuned exhaust, but its not going to be a huge diffrence. cams, well that depends entirely on the grind.

 

 

High Elevation is just the opposite for turbos...

 

First take into account the lower atmospheric pressure, this immediately leads to a loss in pressure everywhere. Everywhere includes the turbo. You can count on 3+ psi loss in most high elevations.

 

The simple solution, install a bigger turbo right? Well not really. This will only increase lag. Consider that at higher altitudes the air is thinner, so you are already looking at increased lag (500+ RPM increases in spool-up). Also, thinner air is not nearly as efficent for the intercooler, simply because there is less of it.

 

Keep your turbo at sea level High performance from a turbo at high elevation is a losing battle from all angles.

 

-Heikki

[erik litchy]

i dunno ive driven both in high altitudes and can say that the turbochargers were definatly working harder, but the engines was about normal, and the non turbo engines are wheezing. Semis dont seem to have too mutch trouble at high alt...I know they pass me up hills when im towing

[BigMattyD]

Regarding the turbo at higher elevations:

 

 

Although the turbocharged car will not perform as well at 15,000 feet as at it would at sea level, it will surely outperform a normally aspirated version of the same engine at either altitude.

 

What I am trying to say is, that if the normally aspirated engine is average at sea level and pathetic at altitude, the turbocharged version will be peppy at sea level, and average at altitude.

 

Overall, I'd rather have the turbo.

 

P.S. That's why pilots of piston-engine general aviation aircraft lust after turbocharged engines; they produce their rated power at much higher altitudes. At a certain altitude, as Heikki pointed out, the amount of boost from the turbo will not be enough to compensate for the loss of atmospheric pressure, and the engine will begin to lose power as the altitude increases beyond that point.

 

Big D

[subyrally]

i had a freind when i was in school that had a 2.5rs that was putting down like 250hp at the wheels with out forced induction. but the engine was no where near stock. i think it was bored and stroked, as well as better cams, exhaust, intake, port an polish, and anything alse one could do to a n/a engine to make power. it was definatly a fast car though.

[Neil '01]

i had a freind when i was in school that had a 2.5rs that was putting down like 250hp at the wheels with out forced induction. but the engine was no where near stock. i think it was bored and stroked, as well as better cams, exhaust, intake, port an polish, and anything alse one could do to a n/a engine to make power. it was definatly a fast car though.

 

How well did the car run? Was it smooth at idle?

 

I would love to swap out the engine. But where can I find a 2.5L turbo engine at a reasonable price? Will there be any problem with the wiring? How much power can my automatic transmission handle anyway?

 

Neil '01

[cookie]

you might want to look at trading for a more powerful car. When I was your age I hopped up everything which usually made the car burn more gas, be less reliable, and ruins the resale value. I was very mechanically inclined and enjoyed doing it.

I think now that a more practical approach might be for you to trade for a newer turbo subie.

Failing that pick up a Pennysaver. There are a few JDM engine places here in the Bay area. They can tell you want a JDM tubo and installation would cost. In the end I think you would come out financially better to trade. If you could do it yourself it might be a different story.

[blitz]

So, it seems that no one is in favor of turbo charging my 2001 Legacy Outback. I looked in to changing out the bottom end to a stronger block, but that seems to expensive and laborious. Does anyone know how much usable power can be gained from new cams and exhaust? The car is used mainly for around town and trips to Lake Tahoe. Would like to have more power in the mountains, but I don't want to rev the engine at 6000 rpm for 2 hours to use it. Any thoughts?

 

I already put a cold air intake on the car because of damage to the stock intake. I was looking at the Impreza power package from Cobb, but doubt that the exhaust pieces will fit. Maybe the equal length headers will fit. Any feedback would be helpful.

The Cobb header gives torque increase through the full rev range (no loss of low end) and their street grind cams give a strong mid & top boost with no loss of low end.

 

Cobb is a reputable company, but there ARE compromises in long-term durability involved. The cam is a high-lift spec with a tad more duration, it'll shorten the life of your valvesprings. It's also a re-weld, so it's not gonna have the same level of non-porosity or uniformity of hardness as the original cam.

 

Cobb's header requires the use of their high-flow cat due to outlet location. The rest of the system is the same.

[cookie]

How much hp and how much torque for how much money? That seems fairly cheap and easy, but he would have to pay somebody to install it.

Just guessing I would think 50 hp for a couple of grand installed might make him happy.

[blitz]

How much hp and how much torque for how much money? That seems fairly cheap and easy, but he would have to pay somebody to install it.

Just guessing I would think 50 hp for a couple of grand installed might make him happy.

From comments that I've read from folks that have fit the Cobb street cam and headers are ecstatic about how it opens the motor up without losing any tractibility. It doesn't make the motor "racy" or burbly at all. It seems as though Subaru's stock exhaust & cam are way stuffy. I'm not 100% certain, but I'd guess that the peak HP would increase by about 30-35 (which doesn't sound like a whole lot) but the benefit is mostly an increase and a substantial widening of the torque curve at both ends.

[JonOfScio]

getting 250hp at the wheels from an n/a motor means he's pushing nascar equivalent output from his motor - and probably would have as much into the motor as his car is worth. driveability would be a problem.

 

you *could* turbo your block... but I'm not sure if 2001 outbacks had the phase II EJ25 or not... (I think they did) but I'm not sure if that motor came with forged internals or what... but the 10:1 CR of that motor means trouble if you don't have a way to adjust your timing and such. It would actually be easiest just to get a JDM 2.0L longblock... doesn't really matter what year a wrx or legacy it's from... and then do the ecu swap. which of course is the *************** in the deal. but in either case of turbo you're still spending lots of money.

 

try to figure out a way to trade your outback for a USDM wrx sedan or wagon and have reasonable payments. We were going to trade my '95 Legacy and my g/f's '96 S10 in for a 2003 2.5RS. If we could have been financed (credit issues) we could have had that $16k car for $200 a month! A couple I know up in p-town area got a 2002 sonic yellow wrx for just over 16k. it was a steal though.

 

but if you'ved amassed love for your particular subie, and the costs of turbo seem too much, putting a lightened pulley set and good headers on should give you more performance without too much cost. and you could always keep adding things to it as your income allows... cams, ecu ad ons, ect.

[Neil '01]

From comments that I've read from folks that have fit the Cobb street cam and headers are ecstatic about how it opens the motor up without losing any tractibility. It doesn't make the motor "racy" or burbly at all. It seems as though Subaru's stock exhaust & cam are way stuffy. I'm not 100% certain, but I'd guess that the peak HP would increase by about 30-35 (which doesn't sound like a whole lot) but the benefit is mostly an increase and a substantial widening of the torque curve at both ends.

 

If I could get 50hp for a couple of grand I would be happy. The Cobb package is about $5,200 installed, but would include having the cylinder heads worked on. I was just wondering if the 50hp is a reality or marketing. Also, I don’t know if the exhaust pieces will even fit. They only list the 1995-1999 Outback. Still waiting to hear back from Cobb.

 

Blitz mentioned the porosity and hardness of the cam’s. How will that affect things? Sorry, but I am kind of a novice in this area.

 

Cookie, I agree that trading up would be ideal, but the Outback is paid for I don’t really want to take on any new payments.

 

Neil '01

[blitz]

Blitz mentioned the porosity and hardness of the cam’s. How will that affect things? Sorry, but I am kind of a novice in this area.

The simplest way to explain it is: if the vehicle in question is the main family vehicle, DON'T mess with it. However, if the vehicle in question is a second "toy", then use Cobb's system. Their HP figures are not exaggerated, but what is assumed is that you (as a gearhead) will gladly accept any "anomalies" associated with building and maintaining a hotrod. It's always been that way.

 

Why? Well, maybe it gets you out of the house ...who knows?

[Neil '01]

The simplest way to explain it is: if the vehicle in question is the main family vehicle, DON'T mess with it. However, if the vehicle in question is a second "toy", then use Cobb's system. Their HP figures are not exaggerated, but what is assumed is that you (as a gearhead) will gladly accept any "anomalies" associated with building and maintaining a hotrod. It's always been that way.

 

Why? Well, maybe it gets you out of the house ...who knows?

 

Wow, never thought I would hear/read the term hotrod applied to an Outback. The car is my daily driver, so maybe it is best to leave well enough alone. Additionally, COBB just got back to me and confirmed that their headers and exhaust won't fit my model year. I couldn't find any other equal lenght headers with a quick search so the project might have to be ditched any way. It doesn't seem wise to spend a lot of money on cams if the gas is exiting through a stuffy exhaust.

 

Neil '01