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Gaining torque?


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So I was interested into gaining some more low end torque for this car. It's a 97 legacy gt, 2.5 dohc

 

So far nothing aftermarket has really been done to the car. There has been tons of replacement parts although as the car puked it's head gaskets up this winter. Got the engine out, new everything, detailed engine bay and engine itself with aged copper paint and the whole works. The engine itself is running really well

 

During the engine refresh I installed the aftermarket uel headers which won't line up with factory exhaust so I just went ahead and got a whole new exhaust as well. It has the headers back to a high flow MagnaFlow cat, 2.5 inch piping back to a borla performance straight through muffler and then a tip from there. Car sounds great but one thing mentioned with the headers is the slight loss of low end torque from them.

 

It's not a huge deal, I love the car either way, but is there any way to gain some low end torque or really just make any sort of power gains in the lower end of the rpm range? Sometimes it just feels like that climb to my power ban takes forever.

 

Basically it just has a really good flowing exhaust is all thats aftermarket, was wondering if there's some sort of intake mod? Any ideas to gain some power?

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A lighter weight crank pulley, electrical grounding kit and maybe throttle body/intake spacers are about all you can do in hopes to get more power/torque out of the motor without more serious mods. If you really want to set the car up to launch, smaller tires would be better with our awd and running 91-93 octane or ethanol mixture will also help dramatically
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My UEL headers are Borla clones. I had to loosen the bracket bolt on the transmission and the catback joint bolts so I could maneuver the cat flange to line up with the header. After that, bolted right up, tightened the bolts down the line, no issues yet.

 

I counteract the slight loss in torque with my lightweight crank pulley which allows it to rev faster.

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Octane won't help on the '97+ as they weren't tuned to run it.

 

You can get Delta Cams, as they likely have a Torque Grind, but expect $100 PER cam (4 total).

 

And don't 'launch it' or you'll be buying a new trans.

 

The stock exhaust AND intake (it is a CAI, BTW) are designed for best overall performance. Headers and a CAI usually just move the powerband Higher in the RPM, reducing low-end.

 

My Subaru Tech doesn't recommend the LW Pulleys as they can mess up your crank....but I know lots of peeps install 'em.

 

Go look on NASIOC or rs25.com the '98 RS is the SAME engine as yours.

 

GL,

TD

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Octane won't help on the '97+ as they weren't tuned to run it.

 

Because Frankenmotor ;)

 

You can get Delta Cams, as they likely have a Torque Grind, but expect $100 PER cam (4 total).

 

This is my next mod :cool:

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I actually run 91 in my car and noticed huge differences in the power aspect. Then again there's no guarantee this is the original motor because it's like a frankenmotor with a long life in Oregon where it's has had deep engine work/swaps

 

I'm not extremely worried about the torque but it would just be nice to get a quicker climb up the rpm range. What dash said seems spot on, the car did seem a little more nimble with the factory exhaust but the headers were worth it in my opinion for sound.

 

I've seen a couple people switching their intake manifold out for one off of a 1st gen legacy saying the bigger diameter in intake piping helps? Not sure if that's valid or not but people have been telling me since I have good exhaust flow I should take advantage and get more flow through the intake and get a tune as well. Again not sure how valid it is

 

I have this weird knock from my engine even after the full refresh that isn't loud at all but it's just there idk what it is but it increases with rpms which sounds like rod knock but it's not, because we took the engine apart, so idk if a lightweight pulley is a good idea

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I built a hybrid cai for my car, which used the stock filter box and a K&N panel filter but then did insulated aluminum tubing straight to the throttle body with no sharp turns or obstructions and with my other mods, my car drives and responds like none of the other 2nd and 3rd gens I've driven. I frequently run higher octane gas as well as I made the semi conversion to run ethanol so I'm going to start testing with that soon. The tune will definitely help to fully utilize the better fuel, but the car will still show gains however small they may be.
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Don't you have to tune to run ground cams? Cause if not I'm going to buy them right now and pull my motor out again, I want a lumpy cam in my turdwagon so bad!

 

Some yes, some no. It all depends on the regrind you choose. I've read about people using their torque regrind without tune with positive results.

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I do have new group N engine and transmission mounts and that definitely helped the responsiveness when paired with the torque solutions pitch stop mount

 

So things that I can afford but worthwhile being cheapish would be a better coil pack (not sure what kind you guys discussed in other threads), a better flowing intake with K&N, and getting the power down a little easier with new underside components. Missing anything?

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Also it seems as though under light load, like if I don't floor it but say give it a quarter to about half throttle around 3k rpms the car seems to hesitate or just kinda lose some power and climb slower until it passes like 4.5k rpm, but only under light load, flooring it you feel nothing. I was thinking maybe it's my throttle body although I juse cleaned it
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better coil pack (not sure what kind you guys discussed in other threads)

 

MSD 8239 is the coil pack you'll need. Here are two how-to threads for installation:

http://legacygt.com/forums/showthread.php/msd-coil-into-subaru-step-step-photos-152338.html

http://sl-i.net/FORUM/showthread.php?7128-DIY-Installing-MSD-Coil-8239-MY96-2-5GT

 

The second how to requires that you have a Neon ignition coil harness. Looks cleaner, if you ask me.

 

You'll also need 2 M6 x 2" bolts for mounting.

 

Also it seems as though under light load, like if I don't floor it but say give it a quarter to about half throttle around 3k rpms the car seems to hesitate or just kinda lose some power and climb slower until it passes like 4.5k rpm, but only under light load, flooring it you feel nothing. I was thinking maybe it's my throttle body although I juse cleaned it

 

Check to make sure your MAF sensor is not dirty and that you don't have any vacuum leaks.

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Oh hell, I just went through a hell of time getting the vacuum lining all buttoned up after not taking enough pictures after the engine refresh. I have this little app that reads the ecu through obd2 port and it reads I run 22.3 to 22.6 something, not sure if that's good or bad.

 

I got the maf from the junkyard about a year ago and cleaned it then before installing it. Old one was toast, should I clean it again?

 

I think I'm probably gonna want to do that coil pack mod as I have a lot of unburned fuel and have heard only good things about this mod.

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it may or may not show you results youre looking for, but it definitely does do something. increased spark always is increased spark, it will allow you to at minimum burn more fuel that is already in the chamber, use a larger gap on your plugs and usually will make the engine not push so much unburned fuel through your exhaust.

 

whether it is a performance gain or not is the debate

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Brighton do you still have the snorkus? I have read that deleting it hurts low end torque somewhere between 1000 and 1800 rpm.

https://forums.nasioc.com/forums/showthread.php?t=1471819

 

I have no idea what that even is haha, the only original parts left is the modified filter box without any of the parts inside the fender, and the MAF. And I didn't dyno it before or after but my butt dyno says mine has a lot better response and pick up then any of the other 2.2Ls I've driven. I've driven maybe 8 other legacies, outbacks and a forester (2.5 blew up) with 2.2s and they are really struggle to move themselves about unlike mine.

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I have no idea what that even is haha, the only original parts left is the modified filter box without any of the parts inside the fender, and the MAF. And I didn't dyno it before or after but my butt dyno says mine has a lot better response and pick up then any of the other 2.2Ls I've driven. I've driven maybe 8 other legacies, outbacks and a forester (2.5 blew up) with 2.2s and they are really struggle to move themselves about unlike mine.

 

The snorkus is that part in the fender that you removed. Check that link that choover posted. You do get better response above 1800 RPM, but the ECU dumps more fuel because without the snorkus and snorkel tube, the MAF thinks it's intermittently dumping gobs of air into the motor. You won't get a CEL from it because above 1800 RPM, the O2 sensors equalize the AFR, but you're actually losing acceleration and power, not to mention fuel economy, but deleting the snorkel tube, snorkus, and modifying the air box.

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Oh hell, I just went through a hell of time getting the vacuum lining all buttoned up after not taking enough pictures after the engine refresh. I have this little app that reads the ecu through obd2 port and it reads I run 22.3 to 22.6 something, not sure if that's good or bad.

 

I got the maf from the junkyard about a year ago and cleaned it then before installing it. Old one was toast, should I clean it again?

 

I think I'm probably gonna want to do that coil pack mod as I have a lot of unburned fuel and have heard only good things about this mod.

 

22-23 inHg of vacuum is good. I would clean it again. The new coil pack doesn't really burn "more" fuel. It just burns the fuel and air more efficiently. If you have a rich running condition, you have an imbalance in AFR. If you're not getting any codes with it, it isn't too far outside of the ECU's threshold.

 

As I've learned the intake tube makes a difference. Most people, myself included, remove the snorkel tube and the resonator box (also called snorkus). Basically, the intention of said components is to keep the balance of MAF sensor's normal running frequency from picking up the resonant frequency of the pressure changes on the intake valves. This resonance is detected by the MAF and ECU between 1000 and 1800 RPM and causes the MAF sensor to create false readings to the ECU that up to 5-6 times the normal volume of air is being put into the engine. To compensate, the ECU dumps more fuel in the engine causing a rich burn condition. The article that choover posted a few threads up breaks it down scientifically more in depth.

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Damn tax man! I have to get caught up so I can get a welder so I can put my wideband on my new exhaust so I can play with this. I'm trying to design a snorkus replacement that flows better, but doesn't lose it's mind on the low end.
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Damn tax man! I have to get caught up so I can get a welder so I can put my wideband on my new exhaust so I can play with this. I'm trying to design a snorkus replacement that flows better, but doesn't lose it's mind on the low end.

 

You don't need a wideband to detect the resonance changes, the MAF sensor does that for you. There is a testing procedure in the link choover posted. A cheap-o Bluetooth OBD monitor and the Torque app does it well. The snorkus doesn't inhibit flow. The only way to get around the snorkus is to convert to a MAP system, or a really long tube that offsets the resonance of the valve train.

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The snorkus is that part in the fender that you removed. Check that link that choover posted. You do get better response above 1800 RPM, but the ECU dumps more fuel because without the snorkus and snorkel tube, the MAF thinks it's intermittently dumping gobs of air into the motor. You won't get a CEL from it because above 1800 RPM, the O2 sensors equalize the AFR, but you're actually losing acceleration and power, not to mention fuel economy, but deleting the snorkel tube, snorkus, and modifying the air box.

 

I'm sure it's beneficial to have, why would the people engineering it make it if is didn't serve a purpose? I bought my car with the Hot air CAI which had a far too large cone filter on it, the car would fall on it's face anytime you tries to give it some throttle because it would bog down with too much air. so I made that cai into the hybrid, but honestly I am not going to bother with the snorkel, just because I have other things in the fender taking up space now.

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