2.5i input

B

blmpkn

Pascifist Patriot
Ive already slapped in a k&n panel filter, magnetic drain plug, and switched to synthetic. From what ive been reading, the crank pulleys on a 2.5i's are junk. They seperate and cause a big headache. This gives me another excuse to buy a perrin lightweight job.

anybody have one? did it make any difference? (quicker revs, higher mpg)?

I forget the company, but they make a composite or whatever non-heat tranferring intake manny gasket. essentially because of the material the gasket is made of, heat from the motor isn't soaked up by the intake manifold allowing the air to stay as cool as possible all the way to the motor. Cooler air is better, we all know this, and it seems like it could be something worth doing.

Anybody have experience with one of these spacers/gaskets?

 
Would this be the gasket?

http://www.forgedperformance.com/store/product.php?productid=17874

Info from the site:

Specifications:

Isolates inlet manifold from engine and cylinder head

Reduces inlet air temperature

Reusable with no deformation

Higher temperature resistance than plastic gaskets (+500 degrees F)

Precision CNC manufactured Includes

Hylomar Universal Blue Racing Formula sealant

Race proven

Safe with all fuel types

Subaru EJ25 2004+

Part number includes one pair

While I do not have experience with them I can say the only time you may notice a difference is if your block is reaching temperatures of 400 degrees, if it is I would look into it. Also the intake manifold on these cars are aluminum if I remember correctly, I do know the 2011s have a plastic manifold. Aluminum has excellent heat transfer properties. As far as how much heat is soaked into the intake, I don't think there is much. The heads have coolant between the exhaust and intake which removes a lot of the heat. For $80 I am sure there are improvements that would be a lot more worthwhile. The general trend recommended is tires, suspension, driver upgrade, power.

 
Lightweight pulley is supposed to be noticable. I have had a few different exhausts and they don't do too much. Next one will be larger pipe so that may help. Make it drive and ride better, it'll already smoke riced out civics, what more do you need?

 
I put a borla muffler (custom fit welded) on my 01outback which helped with exh flow and easy. Still have stock exh?

About that intake gasket any amount of temp lowering that can be done to intake is going to in some way help make the engine more efficient and powerfull, though noticable maybe not. Pulley probably would help, but whats the cost, im not familiar.

 
I had a LW pulley on my 00 RS. That and pulling off the AC belt gave noticeable quicker revs and maybe a couple HPs. The power gain wasn't too noticeable. The quick revs was.

The spacers you are taking about are phenolic spacers. Grimmspeed and KS Tech sell them. You will definitely feel the difference in temperature of the intake manifold, and will equate to maybe 2-3 HP, probably like what a LW pulley will do.

The unfortunate thing about NA cars is single mods most of the time don't really bring out power and performance. You really just have to throw a couple things at it at once to notice that gain. I guess you can say when modding, just look for other key advantages of the parts. For instance, I loved my LW pulley because it was expensive, was made of aluminum (no rust), looks nice(got rid of that OEM eye sore of a pulley), and let me have a little more fun with my car.

Another thing you might want to try, if you're going for phenolic spacers, is the throttle body coolant bypass mod. Subaru from the factory plumbs the coolant to the throttle body butterfly to prevent it from sticking in the winter. It also warms up the throttle body, thus warming up the incoming air. I talked to Bren Tuning about the mod ever really affecting the butterfly from staying shut and he has never heard of anyone's butterfly freezing shut because of this mod.

 
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Well after finding out Grimmspeed makes them and looking at their website I would say they would help. To me they are not gaskets but spacers. All throttle body v8/v6s can have a throttle body spacer installed which does almost the same as these "gaskets." Gasket to me means something 2-3 mm thick.

 
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@jake- I welded on some ebay cans because I couldent justify spending hundreds of dollars on an exhaust that I wouldent really gain power from.

I plan on removing my resonator and welding in a single inlet dual outlet flowmaster in its place. That would give me 2.5" pipe essentially from the cat back (or 2.25 to the muffler than 2.5 out) and ill call it good with exhaust.

Ill have to look up the by-pass mod.

Im quite aware its near impossible to squeeze more power out of these 2.5i's, and im not looking to really invest the money to try. My goal is a motor with a few minor bolt ons/modifications to help reliability, efficiency, and mabey have a bit more fun and gain (mabey) a few ponies. So naturally the LW pulley and intake gasket stand out somewhat.

 
true on $ my borla was a leftover from my old rabbit. Strait through
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. Liking the throttle body coolant bypass idea. May try it.

 
Only bolt on you need. <a href="http://www.raptorsc.com.au/kits.php?id=49" class="bbc_url" title="External link" rel="nofollow external">http://www.raptorsc..../kits.php?id=49</a> at least this will give you actual HP gains. But as said the engine is already putting out as much as it can. A wise man once said, "if you want to go faster buy better tires".

 
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Gate4jg said:
Only bolt on you need. <a href="http://www.raptorsc.com.au/kits.php?id=49" class="bbc_url" title="External link" rel="nofollow external">http://www.raptorsc..../kits.php?id=49</a> at least this will give you actual HP gains. But as said the engine is already putting out as much as it can. A wise man once said, "if you want to go faster buy better tires".
Click to expand...
Im having a hard time believing that a 2.5 SOHC with a supercharger would come anywhere close to 250hp with a supercharger. The WRX engine is a 2.5 DOHC with a non-parasitic turbo and it only makes 220hp in that model year with more than 6psi boost. I bet that would push it up to maybe 200hp if it was properly tuned though.

 
all that matters with the supercharger is the amount of air that it can flow, not the max boost it can produce.

You can have a gt35 turbo produce 18psi as well as a vf-52 produce 18psi, but the gt35 will produce a lot more airflow than the vf-52

 
Im confused, the GT35 would simply not loose boost as quickly would it not? If you have 18psi it simply means that the engine could not suck in the air as fast as the turbo could compress it at that point in the power band. If the supercharger could not produce 18psi under any condition then how could it possibly outflow a turbo that hits higher booste on the same engine? To that end, the Supercharger takes about 30 to 40 horsepower to run because its belt driven where the turbo takes almost no power to spool it becuase it is exhaust pressure based. So how could the supercharged SOHC 2.5i make more power than the DOHC 2.5 Turbo? As far as the GT35 goes, it might have more airflow but it would also maintain 18psi a lot further in to the power band correct? I bet if they didn't have a blow-off valve the GT35 would outboost the VF25... before it explodes... right?

 
I have created a monster. lol All I know it does make that horse power. Look on youtube plenty of videos proving it. The selling point of that supercharger is it takes no time to install, a quick ecu reprogram and a way you go. If you decide not to run it just take off the belt and your not hurting anything. Also if you decided to buy a new car with the same engine. Off it goes and no one would have known and put it on the new car if you like. For quickness and simplicity for getting more hp out of a 2.5i NA engine I don't think anything can match it. Granted it s not cheep but would pay off over a few cars down the line.

 
What it really boils down to is that a belt driven supercharger will build boost a lot different then that of a exhaust driven turbocharger. Superchargers have essentially no lag where a turbocharger has varying lag. In a turbocharged setup boost is created by the mass airflow and velocity going through the the exhaust side(turbine) of the turbocharger. In order to gain more air you need to add more fuel and create more mass going through the exhaust side of the turbocharger. This will bring the air up to what is required for the fuel(this is why diesel trucks will puke black smoke at times while accelerating). A supercharger will build boost based on what rpm you are running. Coupling this with good tuning and a lot is achievable. Today's superchargers are clutched just like your AC compressor to eliminate them robbing power. Now this specific supercharger is in the configuration of a snail which is just like a turbocharger. This will greatly reduce the amount of power it will rob. Your typical Roots,

http://www.rs25.com/forums/f7/t27120-dyno-chart-supercharged-legacy-wagon.html

 
I like it. Im sure you can get a bunch of power out of it, but for how long. You can boost the crap out of anything but things go boom sooner when not originally designed for it. I like the idea of the supercharger bolt on if tune moderately go for longevity.

 
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