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Old 04-04-2012, 02:14 AM   #1
forestersub
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Default Extra Torque ?

Hi Guys, i have an 06 Impreza 2 litre NA. i don,t want a rocket ship thats why i bought a non turbo model but i would like just alittle more low down torque as i feel this would be great to match the higher end mid range torque i allready seem to have and very happy too.
OK what i want to do is; firstly fit the good K&N air filter element, better breathing as we know.
i have picked up a nice 3A Racing brand twin tip stainless muffler that i want to fit up with a custom bent 2 1/4 inch diff back pipe, and for the front area i would like a good header pipe set either UEL or EL.
what do you NA guys say about this ? any tips and please forget the word Turbo or WRX.
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Old 04-04-2012, 03:53 AM   #2
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Want torque? Get cams. Although it's more work, you get a helluva lot more out of a set of cams than you will from I/H/E. And it's a lot cheaper. Or do it all.
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Old 04-04-2012, 04:11 AM   #3
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mod cams are good but you still need other engine parts to assist in the intake and outlet of . years ago we used to fit high lift camshafts to our holden / ford and valiant engines but also we had to use other parts like double valve springs / bigger carbies / extractors etc , not to mention larger valves to suit the big cam.
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Old 04-04-2012, 07:44 AM   #4
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Quote:
Originally Posted by forestersub View Post
Hi Guys, i have an 06 Impreza 2 litre NA. i don,t want a rocket ship thats why i bought a non turbo model but i would like just alittle more low down torque as i feel this would be great to match the higher end mid range torque i allready seem to have and very happy too.
OK what i want to do is; firstly fit the good K&N air filter element, better breathing as we know.
i have picked up a nice 3A Racing brand twin tip stainless muffler that i want to fit up with a custom bent 2 1/4 inch diff back pipe, and for the front area i would like a good header pipe set either UEL or EL.
what do you NA guys say about this ? any tips and please forget the word Turbo or WRX.
I had exactly the same goals as you (albeit with the 2.5 motor), i.e. improve low down torque.

2.25" exhaust is a good start, especially to retain the low end.

From my limited experience, the easiest way to get better low down torque is with a decent set of EL headers and high flow cat, plus you will get better performance through the whole rev range. I was lucky to get a set of Lachute Performance ss headers , they aren't cheap but they're one-offs manufactured to order, and for the performance and a lifetime warranty totally worth it IMO.

Cams may help, but if you want low down torque stick with something like Delta's 1000 grind (often referred to as their 'torque grind') cams. I didn't experience as big a gain as the headers. From here on you're tearing the engine apart so it can get time consuming as well as expensive, so then you will definitely start hearing the words 'turbo' & 'wrx'

Always get a tune, to optimise the mods you do.

Just my 2 cents, i'm sure some of the more knowlegeable folk will chime in soon....

PS. Don't forget to fill in your profile so people know where you are (though the fact that have a 2 litre and you're talking about Holden's i'm betting Oz - G'day!). It'll help when people are recommending products etc.

Last edited by NH8991; 04-04-2012 at 07:51 AM.
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Old 04-04-2012, 10:06 AM   #5
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Quote:
Originally Posted by forestersub
Hi Guys, i have an 06 Impreza 2 litre NA
2.0? Not from North America then...


Quote:
Originally Posted by forestersub
i don,t want a rocket ship thats why i bought a non turbo model but i would like just alittle more low down torque as i feel this would be great to match the higher end mid range torque i allready seem to have and very happy too.
Bolt-on mods will hardly add torque - they will just shift the peak. Get low-end, you'll lose on the high end.


Quote:
Originally Posted by forestersub
OK what i want to do is; firstly fit the good K&N air filter element, better breathing as we know.
Not really, the filter doesn't make any tangible difference.


Quote:
Originally Posted by forestersub
i have picked up a nice 3A Racing brand twin tip stainless muffler that i want to fit up with a custom bent 2 1/4 inch diff back pipe, and for the front area i would like a good header pipe set either UEL or EL.
ELs will improve the engine's TQ/HP... but you might gain it at higher RPMs, not lower. A better flowing exhaust benefits at the peak of the airflow (i.e. high rpms), sacrifising low end pupp. IAs far as the catback goes, it doesn't do much either since it's the cat that is the most restrictive..
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Old 04-04-2012, 03:20 PM   #6
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Lighten flywheel and pulleys will help on bottom.
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Old 04-04-2012, 09:23 PM   #7
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Are there downsides to lightening the flywheel and pulleys?
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Old 04-04-2012, 10:42 PM   #8
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Quote:
Originally Posted by cal_look_zero View Post
Want torque? Get cams. Although it's more work, you get a helluva lot more out of a set of cams than you will from I/H/E. And it's a lot cheaper. Or do it all.
Cams are good and all but without supporting mods they are leaving a lot on the table.

Quote:
Originally Posted by forestersub View Post
mod cams are good but you still need other engine parts to assist in the intake and outlet of . years ago we used to fit high lift camshafts to our holden / ford and valiant engines but also we had to use other parts like double valve springs / bigger carbies / extractors etc , not to mention larger valves to suit the big cam.
Firstly, wtf are "carbies" and "extractors"? Larger valves on a EJ engine are a complete waste of $ and time unless you are building a full race motor. Your experience with large, pushrod V-8 motors does not translate well to the EJ subaru motors.

Quote:
Originally Posted by Bluefoton View Post
2.0? Not from North America then...
I think he means Naturally Aspirated.

Quote:
Originally Posted by Bluefoton View Post
Bolt-on mods will hardly add torque - they will just shift the peak. Get low-end, you'll lose on the high end.
Appropriately designed cams will improve tq in most rpm ranges. With well designed headers, gains can be made in the entire stock rev band with Delta 1000 grind for example.

Quote:
Originally Posted by Bluefoton View Post
Not really, the filter doesn't make any tangible difference.
You forgot about all the dirt and crap that a K&N lets into the engine. It's like an intake P&P while you drive!

Quote:
Originally Posted by Bluefoton View Post
ELs will improve the engine's TQ/HP... but you might gain it at higher RPMs, not lower. A better flowing exhaust benefits at the peak of the airflow (i.e. high rpms), sacrifising low end pupp. IAs far as the catback goes, it doesn't do much either since it's the cat that is the most restrictive..
EL's can make gains at high end, low end, mid range, or nowhere. OR... they can make gains everywhere if they are designed well. It's all about the dimensions and collector in addition to the EL design. They can be tuned to make peak gains in one area but they dont have to sacrifice in the other relative to the stock manifold. TWE's are a great example of improvements in tq over the entire rev band, better throttle response and the increases in scavenging allow for a great side effect... increases in mpg's.

Quote:
Originally Posted by mod maniac View Post
Lighten flywheel and pulleys will help on bottom.
They accelerate with less energy but they don't actually make any gains in power. They make the car feel more responsive and eager to accelerate.


Quote:
Originally Posted by Culverin View Post
Are there downsides to lightening the flywheel and pulleys?
Only from the engine computers standpoint. unfortunately, if the ECU is not happy it can be quite a headache, especially if you have to pass any sort of emissions testing. this is dependent on how sensitive the ECU is, and how much of a change in rotational mass is made.


IMO the best bang for your buck to make real, noticeable gains in low end tq, is a well designed set of EL headers. You will also benefit from gains in mid range and high end tq, and increased fuel efficiency if you can run more ignition timing advance. The 06 will automatically take advantage of being able to advance ignition timing to some degree. Chances are that you will not max out the advance built into the ecu unless you have super high octane gas and very cold intake temps in addition to some nice headers.
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Old 04-05-2012, 02:26 AM   #9
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seems like raceface doesn,t get the drift in what i am wanting in regards to abit more low down torque. heaps of replies to all thanks bud.
whats wrong with the K & N aircleaner element ? one of the best.
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Old 04-05-2012, 02:42 AM   #10
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The lightened flywheel and pullys do free up torque so you have better pull down low, but race face is correct that you have to be careful not to go to light or the ecu can get fussy.
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Old 04-05-2012, 03:13 AM   #11
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i even know you will not gain any extra torque from a lightened flyweel plus light h / balancer. these will only give your engine extra low end rpms not Torque. keep the info a comin guys.
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Old 04-05-2012, 08:54 AM   #12
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Quote:
Originally Posted by RaceFaceXC
I think he means Naturally Aspirated.
Yes, but what I meant is that someone with a 2.0 N/A before 2012 is not from North America (unless he ripped off his turbo)

Quote:
Originally Posted by RaceFaceXC
You forgot about all the dirt and crap that a K&N lets into the engine. It's like an intake P&P while you drive!
love it.

You're right to have corrected me on the torque curve discussion btw. I just figured that if the OP just plays with air filters and exhaust, he won't be digging into cams..
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Old 04-06-2012, 12:46 AM   #13
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Get stickers! I have heard they help A LOT!
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Old 04-06-2012, 01:29 AM   #14
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Get stickers! I have heard they help A LOT!
Yea thats it. How could I have missed that one.
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Old 04-06-2012, 07:39 AM   #15
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Quote:
Originally Posted by RaceFaceXC View Post
They accelerate with less energy but they don't actually make any gains in power. They make the car feel more responsive and eager to accelerate.




Only from the engine computers standpoint. unfortunately, if the ECU is not happy it can be quite a headache, especially if you have to pass any sort of emissions testing. this is dependent on how sensitive the ECU is, and how much of a change in rotational mass is made.


Is the lightening of the flywheel and pulleys something that can be done with a just a bolt-on swap? One that's proven not to make the ECU throw a hissy-fit?
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Old 04-06-2012, 09:43 AM   #16
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Quote:
Originally Posted by Culverin

Is the lightening of the flywheel and pulleys something that can be done with a just a bolt-on swap? One that's proven not to make the ECU throw a hissy-fit?
I'm not quite sure what you are asking, but pulley/flywheel are "bolt on" mods as in you take the original off and bolt on the new one. Any flywheel that is considerably lighter seems to make the biggest difference for performance and for not getting along with the ecu. Combine that with a crank pulley and it's more of both. I have not done either mod but it seems like a crank pulley makes a slight difference without causing any ecu problems.
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Old 04-06-2012, 10:22 AM   #17
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The lightened flywheel route might make your small-ish 2.0 a bit less driver friendly when starting from a stop. Once you are rolling, the reduced mass takes less power to accelerate, so more can get to the wheels.

Yours is a DOHC motor, correct? If so, you may look into altering the cam timing to increase the torque. It will surely effect the top end as well, so be mindful of that.

Lighter pieces parts everywhere you can afford will benefit your goals. Dropping 3-5lbs per wheel will not add any torque to the motor....it will add more torque at the wheels, and you will accelerate quicker, as if you were making more torque.

Have fun!
Jay
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Old 04-06-2012, 11:40 AM   #18
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Don't go below 12.5 lbs on the flywheel.
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Old 04-07-2012, 02:03 AM   #19
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Update on progress. [ extra torque ]
a new set of 4-2-1 stainless EL headers which to be heat wrapped tonight.
1 x 2 1/4 inch ID high flow stainless cat.
1 x 2 1/4 inch I.D. 16 inch resonator.
1 x 2 1/4 inch inlet x 2 x 3 inch tip outlets 3A Racing muffler.
just need to go to my exhaust shop and have the guys bend up a diff back 2 1/4 inch pipe plus a matching mid pipe to cat.

picked up a nice K & N aircleaner element plus a can of aircleaner oil.

let you guys know how all goes in a few days.
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Old 04-07-2012, 05:41 PM   #20
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Do you have access to a dyno so as to measure the before and after?
I'd drop the K&N though. Stock filter is more than capable..and doesn't polish your guts with oily crap
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Old 04-07-2012, 11:01 PM   #21
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Quote:
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Do you have access to a dyno so as to measure the before and after?
I'd drop the K&N though. Stock filter is more than capable..and doesn't polish your guts with oily crap
if you know how to PROPERLY clean and oil a k&n you wont have this problem. but those of you who bash those filters are probably the ones who over oil them and then run into problems. honestly if K&N's were as bad as you guys make them out to be, do you really think they would still be in business? im running one now and have been running one since i got it and my past 2 cars have had them. i have never had a problem or anything. then again i dont "soak" mine in oil. as it states in the instructions it says... light coats till its all red while waiting a couple min between coats to let it soak in.
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Old 04-08-2012, 01:02 AM   #22
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yes i was also quite surprized about the comment on the K&N filter. these airbox filters are much better than the genuine paper element by far, they don,t just let your engine breath easier but they also last the lifetime of your vehicle. before i swapped over to subaru vehicles i owned large 4 x 4 off road vehicles and allways used K&N Filters without any issues whatsoever , i am saying over 20 years of 4 x 4 ing.
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Old 04-08-2012, 11:51 AM   #23
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There are extensive discussions about K&N panel filters on here. Do a search. There are a lot of people VERY much opposed to using them. I would read up and see what people have to say and draw my own conclusions but there is a lot of interesting info/points
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Old 04-08-2012, 05:47 PM   #24
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Quote:
Originally Posted by krzywhtboi82

if you know how to PROPERLY clean and oil a k&n you wont have this problem. but those of you who bash those filters are probably the ones who over oil them and then run into problems. honestly if K&N's were as bad as you guys make them out to be, do you really think they would still be in business? im running one now and have been running one since i got it and my past 2 cars have had them. i have never had a problem or anything. then again i dont "soak" mine in oil. as it states in the instructions it says... light coats till its all red while waiting a couple min between coats to let it soak in.
Oiling is only a small part of the problem. 1000 miles after installing a new out of the box k&n I had to clean my maf mast.

Quote:
Originally Posted by forestersub
yes i was also quite surprized about the comment on the K&N filter. these airbox filters are much better than the genuine paper element by far, they don,t just let your engine breath easier but they also last the lifetime of your vehicle. before i swapped over to subaru vehicles i owned large 4 x 4 off road vehicles and allways used K&N Filters without any issues whatsoever , i am saying over 20 years of 4 x 4 ing.
they don't let the engine breathe easier because the factory paper element filter is not a restriction. the forum @ bob is the oil guy had a thread where the k&n was tested thoroughly. The pressure drop across the filter was the same within the equipment margin of error for paper element, k&n and no filter. It also showed a huge difference in dirt, debris after the filter when using the k&n vs. the paper over the same mileage/duty. UOA also showed higher than avg silica values when I had a k&n, and lower than avg values when I replaced it with paper element.

They sell them mostly because marketing them is easy when idiots believe everything applies to them and their vehicles and partly because there are some vehicles with poorly designed intake systems that do actually have a restriction at the filter. If the wrx has the identical airbox/filter and flows 60% more air by mass, it's unlikely that it's restricting the n/a intake.
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