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Performance GAIN after fuel filter change??

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tsi1991awd

10+ Year Contributor
1,366
6
Sep 28, 2008
Puyallup, Washington
So I just changed my fuel filter...wasn't bad AT ALL. Was very easy, took maybe 20 minutes total, most of it being the battery brackets that had to be taken off/on. But anyways, wanted to ask if anyone has seen a performance GAIN after changing the fuel filter??

The old filter didn't have any brown gas as some people describe. It was regular gas, but I'm assuming it could have been clogged. Because afterwards, I took it down the road and it hauled ass...feels like a completely different car and I don't know if this is normal, LOL.
 
when friend of mines changed his fuel filter (he had stock injectors and stock fuel pump) he didn't felt nothing.
when i changed my fuel filter couple months ago,i felt a big different,cause my old fitler had a lot of brownies inside it LOL LOL) So after that i saw that i was running rich,because more fuel probably were injected to the motor without any restriction ;)
 
I noticed a difference when I changed out my filter.. It was dirty as hell..But then started to run rich, keep an eye on that. Rich won't hurt anything, but will hurt your pocketbook(gas milage). Also you will notice a different smell coming from exhaust, because of more fuel is being crammed in you engine.
 
I don't know what happened then...maybe everyone sees varied results? There was no brown stuff coming out of the filter when I emptied it. Put water through it and it was just all clear. But man, I took off down the road like a bat out of hell and all I did was change the filter. Was at my parents house doing this, and when we were coming home, my wife said it was a lot faster...so I know it wasn't just me.

Maybe the filter was clogged but didn't have any brown stuff, or....I don't really know.
 
I hear ya bro...that filter was holding me back big time. The motor makes about 200hp but how much power is it actually putting to the ground, you know? If I get to about 250whp, I'd be happy. I've driven a stock EVO 8 and that was real nice, quick. I liked it better than the STI. I wonder how much hp gain I'd get from just doing an intake and full exhaust.
 
So I just changed my fuel filter...wasn't bad AT ALL. Was very easy, took maybe 20 minutes total, most of it being the battery brackets that had to be taken off/on. But anyways, wanted to ask if anyone has seen a performance GAIN after changing the fuel filter??

The old filter didn't have any brown gas as some people describe. It was regular gas, but I'm assuming it could have been clogged. Because afterwards, I took it down the road and it hauled ass...feels like a completely different car and I don't know if this is normal, LOL.


It's not common but does happen. More than likely the dirty filter wasn't allowing enough fuel past when demand was highest (under higher boost). This would cause the A/F ratio to lean out and cause knock. The ECU would detect the knock and pull timing causing a power loss.

The improved performance you are noticing now is probably because your timing curve is much better from getting rid of the knock.:thumb:



I noticed a difference when I changed out my filter.. It was dirty as hell..But then started to run rich, keep an eye on that. Rich won't hurt anything, but will hurt your pocketbook(gas milage). Also you will notice a different smell coming from exhaust, because of more fuel is being crammed in you engine.

Actually, running rich is harmful although not necessarily right away. In addition to causing increased carbon deposits there is also more unburned fuel that works its way into the crankcase via blowby. This fuel breaks down the oil leading to premature wear of internal engine components.;)
 
I let my wife drive my car this one day her avenger was in the shop. Turned the boost all the way down. She said I waited like you said till it hit 3500rpm, and it took off. She was like whoa that was fast.. I said hunny that was only 200HP. She came home and said she wanted a 6 bolt in hers, so i'm getting there soon..

How can you say that with the boost all the way down the engine made 200hp?
Did you dyno it with the boost down?
Do you have supporting mods to show your car makes a substantial gain with the 16g installed on your car?

I'd just like to know because of the statement you made.
 
It's not common but does happen. More than likely the dirty filter wasn't allowing enough fuel past when demand was highest (under higher boost). This would cause the A/F ratio to lean out and cause knock. The ECU would detect the knock and pull timing causing a power loss.

The improved performance you are noticing now is probably because your timing curve is much better from getting rid of the knock.:thumb:





Actually, running rich is harmful although not necessarily right away. In addition to causing increased carbon deposits there is also more unburned fuel that works its way into the crankcase via blowby. This fuel breaks down the oil leading to premature wear of internal engine components.;)

This makes more sense than any other.The knock sensor will retard your timing and basically pull needed power to protect the engine!
 
I'm not sure exactly what you are looking for, an opinion or facts? So, I just changed my fuel filter. I didn't necessarily feel a performance gain, but mine was really dirty. The fuel coming out of the filter was brown on the input side. My car had trouble starting sometimes, and once and a while I noticed my rpms dip a little while driving in gear. If your filter is so clogged that your engine has a hard time gasping for fuel, than you might experience more power due to the engine not fighting for fuel. And about what you said about the fuel coming out of your filter looking clean, I would think that if your car felt better afterwards, there was something clean stuck in there like a piece of metal or something. The fuel would then look clean, but maybe the piece is still stuck in there, it fell out when you were not looking, or it's too small to see. At the very least, you have peace of mind knowing that your fuel filter won't cause you problems in the near future. Now, I just have to figure out how to fix the bolts that I broke on the braket because they were so rusty...
 
Yea, I figured something was in there that was clogging it up...not sure what, but doesn't really matter anymore!

My new filter came with the bracket but didn't come with the rubber grommets that go into the bolt holes, so I had to take the old ones out and put them in. Also didn't come with crush washers, which pissed me off...went to Autozone, Shucks, and Ace Hardware and they didn't have any, so I bought what LOOKED to be the same inner diameter at Autozone. Turned out, they are slightly bigger but they worked...hasn't leaked yet, so I guess I'm good!

As far as those bracket bolts, I sprayed PB Blaster on them the day before I did the filter...also on the top bolt and the bottom nut. Sprayed them again about 10 minutes before I was going to be removing the filter and all the bolts came right off. Easy change. Not sure why everone has hard times, because I didn't bust my knuckles, cuss, take 3 hours, etc....took about 20 minutes, mostly because the battery tray brackets and everything.
 
i really need 2 change mine out....and my plug wires, hopefully this will help with my problem of misfiring and such in boost :(

i can see what u mean by feeling more power...its not gaining power, its getting back the robbed power from the old filter, i see what u were trying to say
 
Im hoping my gets the same magic!I have done everything else and the car seems to not be running at its full potential so hopefully this helps!
 
A fuel filter replacement should boost performance about as much as a fresh layer of wax.

what?! wax makes your car more aerodynamic haven't you heard....so thats another 20mph to your top speed...

oh and dont forget to tint your windows for an instant 25 horsepower...
 
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