The official CAI/Exhaust thread for N/A scoobies

[SamCairns]

Originally Posted by suspicious_subaru

Is there anybody else besides inferno fab making catted headers for the 2008-2010 2.5i? I cant find any in a google search and a search here only showed inferno

rallisportautomotive sells UEL headers and some other stuff for 2006-2011 2.5i's.

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[tipsymechanic]

2008 / Subaru / Legacy / EJ253 / 4EAT
Hybrid Intake w/ AEM dry flow filter: Less than ~$125
Infernofab 2.5RS style header w/ high flow cat: $700
Stock LGT midpipe, HKS Silent Hi-Power axle back

Likes: It sounds great inside the car. I can barely hear the intake, the exhaust is deep and rumbly.
Dislikes: I tried to be cheap and got an ebay intake. I hacked it up and used couplers, it doesn't fit quite right. It works, but I'm not 100% happy with it. The exhaust is raspy. I think the Delta Cams are at fault, it was always smooth before they were installed.

I can't really comment on power gains, I'm sure it helps a little, combined with tuning, of course.
This will all change in the next few months when turbo bits are installed

YouTube (Short URL)

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[ImprezaRS dot com]

Originally Posted by tipsymechanic

2008 / Subaru / Legacy / EJ253 / 4EAT
Hybrid Intake w/ AEM dry flow filter: Less than ~$125
Infernofab 2.5RS style header w/ high flow cat: $700
Stock LGT midpipe, HKS Silent Hi-Power axle back

Likes: It sounds great inside the car. I can barely hear the intake, the exhaust is deep and rumbly.
Dislikes: I tried to be cheap and got an ebay intake. I hacked it up and used couplers, it doesn't fit quite right. It works, but I'm not 100% happy with it. The exhaust is raspy. I think the Delta Cams are at fault, it was always smooth before they were installed.

I can't really comment on power gains, I'm sure it helps a little, combined with tuning, of course.
This will all change in the next few months when turbo bits are installed

https://youtu.be/231LsnV2BPo
https://youtu.be/RL9_XJXZ5k0

In my experience, the length and diameter of the intake always affected the torque curve and HP depending on the changes made. If you were going to stay normally aspirated I would consider getting an intake that has already had the tuning put into the design.

Tuning the ECU could make a big difference though, and make you happier. But be very careful when you start adding boost to an EJ25. My 2000 2.5RS was a bit different with it's MAP sensor, but it's still a big risk.

When I added even a simple RB52 legacy turbo kit at 6-psi with a rising rate fuel pressure regulator it made the biggest difference, and 0-60 times up here at 6000 feet dropped from 8+ seconds to 6.0 seconds flat on 93 octane. I didn't stay there though, even after blowing up 2nd gear.

With 100+ octane gas and 2 extra fuel injectors in the throttle body run by an extra EFI computer, my 2.5RS was making 233 whp at 6000 feet above sea-level and running [email protected] quarter miles at Bandimere Speedway. I should have stopped there.

Then I got greedy and broke the rings, built a 9:1 motor with VF22 turbo kit with AW IC at 14 psi and it was probably at 375hp on 93 octane. It was incredible, except when it got boost creep in the mountains in 5th gear with a friend driving and did the motor in again, along with another trashed stock 5-speed gear set.

Then I built a monster 8:1 motor, JE pistons, Pauter rods, knife-edged lightened balanced crank, O-ringed head, Cobb cams, tuned ECU with quad fuel rails and Garrett Ballistic/IHI hybrid turbo, HK BOV, and 6 core AW IC, and dual dump 3" downpipe with about 500hp. And this time blew up 5th gear and the front ring-and-pinon despite having a PAR/Chalak high power gear set that only replaced 1st-4th. The ceramic clutch we installed, after the ACT clutch was slipping, was now grabbing a little too well.

We tried installing a Forester STi automatic transmission since it had the same 4.11 diffs as the 2.5RS, and after 2 months of replacing pedals and shifters and drive shafts and wiring, it was stuck in 3rd gear. So 0-60 (4,000 rpm) felt like a Honda civic, but then finishing out 3rd gear from 60-120mph (4,000 - 8,000 rpm) felt like the Millennium Falcon - everything was a blur.

After that, my wife said, "it's you or the car, one has got to go" and I sold the motor for $5K, sold the turbo kit for $5K, installed a stock motor and rewired the transmission, and traded it for a brand new 2004 STi. I had to leave the 3" exhaust, Tein coil overs, and Wilwood 4-pot brakes on it, as well as the leather seat upgrade that I did after I bought it. After paying the dealership $1,500 to "fix" the transmission issues, I had $9,500 in trade value on a 36 month old 2.5RS that had cost me $20,000.

I think at that point I decided to never mod my car again. The STi was near perfect, although I did do a Cobb tuning access port tune on it. Now I'm in a 2017 WRX and it's only got the STi exhaust and short shifter and no tune - I'm just told old now I guess.

So, after hearing this, do you think you might want to just trade that in for a WRX or Outback Onyx XT?

[tipsymechanic]

Originally Posted by ImprezaRS dot com

So, after hearing this, do you think you might want to just trade that in for a WRX or Outback Onyx XT?

Wow! you did a lot! bet it was fun while it lasted
I had considered a Forester XT, but this car has been paid for since 2013..
I'm only going to run a TD04 at 5-10psi, with AWIC and E85 fuel.. should be fairly safe.. relatively speaking

[ImprezaRS dot com]

Originally Posted by tipsymechanic

Wow! you did a lot! bet it was fun while it lasted
I had considered a Forester XT, but this car has been paid for since 2013..
I'm only going to run a TD04 at 5-10psi, with AWIC and E85 fuel.. should be fairly safe.. relatively speaking

It was a lot of fun - I was boosted 6 months before the WRX was introduced at the Detroit Auto Show in 2001. And my work on boosting the 2.5RS caught Subaru’s attention and got me invited to the show to blog on the introduction, on their dime. They also sent me to the Ride and Drive event at Firebird Raceway.

Your plan is certainly feasible, I just wanted to let you know what you’re in for.

[tipsymechanic]

I can’t even imagine how awesome that would be.. recognized by Subaru! Dang

I appreciate the heads up!

[SandmanSaab]

What are the current options for en equal length header?

[d.angel]

Originally Posted by d.angel

Don’t know if this is still an issue or not. See my post below. When I bought my car it had the current exhaust already on it. Love the low rumble, so I would totally recommend the muffler. But, with the resonator delete, it’s too loud at high rpm +/- heavy accel. Also very tinny sounding, and raspy at high rpm/hard accel. Lots of drone at freeway speeds. I’m adding a yonaka resonator 2.25” in/out and 16” length. Will try to post before/after video of sound. I don’t expect big changes, just settling her down a little. We’ll see.

Thanks for the tips! I actually have UEL headers, my mistake. I put a 20” yonaka reasonator on, and my car sounds great! Just slightly quieter at idle. But otherwise that low Subie rumble goes through the entire rev range. Best of all, no raspiness at all.

[d.angel]

Originally Posted by dirtcrazy

My old 87 GL Wagon (gutted for racing) with an EJ25D had and UEL header, a resonator in place of the cat, a 20" Glass pack, and a magnaflow straight through muffler. All 2.25". It had a mild rumble and zero drone on the highway.

Since you're running EL headers, you'll want a decent sized resonator. So, either go with a large (20+") 2.25" glass pack like i did, or a Vibrant Performance Ultra Quiet Resonator (1140). You might even need a second bottle style resonator to really get the noise under control.

I don't know what kind of space you have under your car, but a second muffler might be another option. But, that's assuming you've got space underneath there for one.


Hope that helps.

Totally heIps. I actually have UEL headers, my mistake. I put a 20” yonaka reasonator on, and my car sounds great! Just slightly quieter at idle. But otherwise that low Subie rumble goes through the entire rev range. Best of all, no raspiness at all.

[tipsymechanic]

Originally Posted by SandmanSaab

What are the current options for en equal length header?

Rallisportracing * MIGHT * make one, I'm not 100% sure. TWE makes good 2.5RS style headers, pricey though.
Stock 2.5i headers aren't bad at all, modify it to get rid of the cat or add a high-flow cat.

[SandmanSaab]

Originally Posted by tipsymechanic

Rallisportracing * MIGHT * make one, I'm not 100% sure. TWE makes good 2.5RS style headers, pricey though.
Stock 2.5i headers aren't bad at all, modify it to get rid of the cat or add a high-flow cat.

That's what I'm finding out. Since I have an 05 I believe that I'll need the header, cat pipe, and the newer oil pan for it all to work.

[tipsymechanic]

Originally Posted by SandmanSaab

That's what I'm finding out. Since I have an 05 I believe that I'll need the header, cat pipe, and the newer oil pan for it all to work.

does your 05 have the RS style manifold or the newer 2.5i style? I forget.

[SandmanSaab]

Originally Posted by tipsymechanic

does your 05 have the RS style manifold or the newer 2.5i style? I forget.

Older, the design that goes behind the oil pan. The new one goes in front correct?

[tipsymechanic]

Originally Posted by SandmanSaab

Older, the design that goes behind the oil pan. The new one goes in front correct?

yep! The TWE equal length design is behind the pan. They're the only one I know 100% makes EL design. The others, I'm not so sure.

[SandmanSaab]

Originally Posted by tipsymechanic

yep! The TWE equal length design is behind the pan. They're the only one I know 100% makes EL design. The others, I'm not so sure.

I'd get it but it's way out of my budget, it's a very nice unit though.

[tipsymechanic]

Honestly, if you don’t mind the UEL sound, anything is better than the stock behind the pan manifold. That thing flows so bad. A cheap UEL will pick up power.

[SandmanSaab]

Originally Posted by tipsymechanic

Honestly, if you don’t mind the UEL sound, anything is better than the stock behind the pan manifold. That thing flows so bad. A cheap UEL will pick up power.

Honestly I already have one. I swear this thing has an exhaust leak I can't find in the header. I'm going to replace it but if I oculd find an afordable EL that's the route I was going to go before getting another cheap UEL.

[tipsymechanic]

Originally Posted by SandmanSaab

Honestly I already have one. I swear this thing has an exhaust leak I can't find in the header. I'm going to replace it but if I oculd find an afordable EL that's the route I was going to go before getting another cheap UEL.

I think your cheapest bet is an OEM 2.5i manifold. None of the other nice headers are under 500, most 700+

[SandmanSaab]

Originally Posted by tipsymechanic

I think your cheapest bet is an OEM 2.5i manifold. None of the other nice headers are under 500, most 700+

Ebay has some for under $100. Not much in between, the newer manifold seems like a decent design, better than the older stocker for sure.

[Spainky]

I have a 2006 Impreza 2.5i with an exhaust leak located in the manifold. Instead of fixing it I'd like to go ahead and replace it. I'd like to have UELs but I wouldn't want to have to replace my full exhaust system. Currently my setup is stock manifold and cat pipe with an STI catback and magnaflow muffler.

Would I be able to get rs style uel headers and a cat pipe and have it bolt right up to the catback or would I need a full exhaust for this to work?
If that doesn't work than what are some good EL headers that would bolt right up? I'd like to go for a decent sound more than anything, my current setup sounds really good unless I get on the gas and it starts to get raspy. Eventually I'd like to replace the muffler with something a little bit more toned down as well since the amount of noise that comes from my car is ridiculous and I think it's had a pretty significant effect on my hearing as well.

[Joey118]

I have a 2004 Impreza Outback currently with a custom made hybrid intake. I’d like to get an exhaust that gives me a little more power, and a slight increase in sound (a little louder and deeper. Just enough to be noticeable and sound nice but not make people deaf). Would this be accomplishable with just a muffler or would it be worth it to go full cat-back? What brands/models do you suggest?