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2004 Forester X - Clutch? More Air?


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Last Saturday I bought an '04 Forester X. Having heard about the clutch chatter issues I will reluctant to buy a 5 speed but figured Subaru had diagnosed the issue by this model year...can anyone confirm?

 

On another note...any suggestions for inexpensive modifications that have proven to boost 2.5 performance? The dealer said a new air filter may help...does anyone have experience?

 

This is my first posting on this site...glad I found this board!

 

Tim

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Sorry I can't be of much help concerning any clutch issues or performance mods. We just bought an '04 Forester XT w/5spd a few weeks ago and have only a little over 1000miles on it. So far so good though :grin:

However, I would like to say congratulations on the new car and welcome to USMB :clap:

-Louis-

'04 Forester XT 5spd

'91 Loyale 4wd 5spd Wagon

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Last Saturday I bought an '04 Forester X. Having heard about the clutch chatter issues I will reluctant to buy a 5 speed but figured Subaru had diagnosed the issue by this model year...can anyone confirm?
You have the redesigned clutch. No worries.

 

On another note...any suggestions for inexpensive modifications that have proven to boost 2.5 performance? The dealer said a new air filter may help...does anyone have experience?
Keep with the OEM air filter. K&N and its ilk yield little or no increase in output at the expense of allowing more wear-causing particles into the engine.

 

If you want to increase output of a naturally-aspirated engine, cams are your best bet. To expensive? Perhaps a freer-flowing cat-back exhaust will get you a few more ponies. Don't bother with a cold-air intake. You already have one.

 

I've not confirmed this with dyno. runs, but my '02 Legacy (same mill as in your Forester) feels more powerful when run on premium unleaded. Remember, this engine has a 10:1 compression ratio, which seems a bit high for gasoline with an AKI of 87. Perhaps the ECU is allowing more advance when I'm running with the premium fuel. I could confirm this if I had some wiz-bang OBDII software and an interface cable.

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I've tried a variety of inexpensive modifications to my '98 OBW w/the Phase I EJ25 (4 cams). Your Forester has the Pase II EJ25 (2 cams), but I think they would respond very similarly to modification.

 

The single best modification I have done has been a light weight, stock diameter crankshaft pulley (the pulley at the bottom front of the engine that turns the alternator and AC belts). The aftermarket pulley is several pounds lighter than the steel factory pulley. The removal of those several pounds of weight that the engine must spin frees up power (much, much more so than removing an equal amount of unspun weight). This modification was very noticeable.

 

There also are smaller than stock diameter (underdrive) light weight pulleys, but these spin the car's accessories (including the alternator) at a slower speed, thereby reducing their output. This may or may not be a problem (I live in Maine so I want the alternator providing the battery with full charging power in the winter). Further, I have heard that most of the power gain from a pulley change comes from the reduction in weight, rather than from changing the diameter of the pulley.

 

The next two best modifications were (1) replacing the stock filter with a K&N air filter and (2) removing the intake silencer located in the passenger side fender. Both made a noticeable improvement, but not as big as the pulley.

 

Some people bash K&N filters. Others swear by them. I have had mine for about 29,000 miles with no ill effects. There are two things to avoid (1) frequent driving in dusty conditions (I live on a short dirt road, but that's not enought to be a problem) and (2) over oiling the filter when you clean it (I clean mine once a year). To be honest, it takes a large degree of carelessness to over oil the filter.

 

Removing the air intake silencer improved power, but it also increased noise. The snarl at higher RPMs is nice, but the car also makes a droning noise at idle.

 

I also have performed the so-called grounding mod--adding additional grounding wires between body, engine, and battery, but didn't notice much difference.

 

Oh yeah, last year I spliced in a Pro ECM Powerchip. I had really bad luck with it. It caused the car to stall repeatedly during in town driving. I have since removed it.

 

You might want to check out these sources for performance parts:

http://www.rallitek.com/

http://home.att.net/~teaguesauto/

 

Happy motoring!

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A couple of things to keep in mind.

 

The intake tract for the Phase-II (SOHC) 2.5L is different than that for the Phase-I (DOHC). To be more specific, the Phase-II has an air inlet just above the passenger-side head light (woo-hoo, factory cold-air intake!), and a resonator chamber just behind the ABS module. It's actually very well designed.

 

As for the pulley, don't forget that it acts as a damper as well. Its mass may serve to cancel some crankshaft harmonic. I'll check the factory service manuals when I get a chance.

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