Where to start?

[dwallar]

Hi All. I am new to this forum. I have a 2011 LGT in dark charcoal and just spent a bit of money to fix up some rust spots on the left rear quarter panel and the roof as I have decided to keep this car 'cause I love it so much. Am second owner, bought it in 2013. Has 167,000 kms on her, new clutch, new 1st and 2nd gear synchros, and rear shift fork.

My question is: If I wanted to start tuning the car to increase HP, is it worth it on a car with this many km's? If so, where to start. There is a Subie performance tuner near me called Definitive Tuning. I spoke to them a couple years ago and they suggested a Cobb programming unit (apparently a must have) to flash the ECU, and a down pipe. If I wanted to go a bit further, what would the priorities be? I'd like to get, say, 350+ HP if possible, maybe 400. What is a reasonable amount to spend?

 

Appreciate any and all advice.

 

Thanks,

[A_A_ron]

350 to 400 HP is a lot for these cars but there is more to power than peak horse power. If you are serious about going for that much hp you will need a ton of supporting mods. I would say a good first step before you drop 5-10k is to get ARP head studs in it, a drop in panel filter, and a nice dyno tune.

 

This car really opens up the power band from stock with a good tune. It may only be 10-15 more hp than factory at peak but in your 4k rpm range it might be 50 more hp. I strongly recommend you thoroughly read this stickied thread containing a lot of lessons learned about power in the 5th gen gt platform from the people who trailblazed back in the early 2010s.

 

https://legacygt.com/forums/showthread.php/5th-gen-gt-power-roadblocks-and-solutions-259192.html

[FLlegacy]

First off, consider how you use the car. If it's your daily driver just forget the 350-400hp right off the bat. Jpipe, aftermarket bpv, and maybe an ebcs with a protune will get you close to 290hp and 330lbft of torque on 93 octane. That makes for a great daily driver and will pull away from most anything on the road especially in the wet/snow. And it is genuinely fun and mostly reliable provided you aren't launching or flat foot shifting.

 

Beyond that gets you into some really gray areas of reliability that would be more suited to a fun vehicle/project vehicle that you don't "need" every day.

[Golferdude1087]

Beyond what FLlgeacy said, you will need an IAG block, new turbo, and a bunch of other stuff. Its going to cost a LOT to get well past the 300whp range

[dwallar]

Thanks guys for all your feedback. OK, I get it. I am way out of line to think in those HP ranges. Yes, it's a daily driver and I don't want to break it!

So here's what I'm hearing:

1. A J-pipe

2. An aftermarket bypass valve

3. An electronic boost control solenoid with a protune.

 

What about the exhaust system? Is it worth it to replace with J-pipe, new CC, and catback exhaust. If so, what's the best one to increase performance but only slightly increase the sound. I don't want it to sound like a boy-racer car.

 

Thanks,

 

Don

[creep_nu]

agreed with the others, a good tune really opens up the engine. big money and unreliability is what it's going to take to get to the 350-400 wheel mark. i was shocked at the night and day difference a tune made on my car--stock intake and exhaust and on a stage 1 cobb tune really did a number on low to mid range power on the car...went from kinda sleepy down low to quick and extremely usable.

 

if you really want to push the car like others have said you're looking at new turbo territory and the plethora of supporting mods that go along with it. it's doable, and been done, but it's not easy, and given that you're asking the questions unless you plan to learn to do the wrenching yourself, it certainly won't be cheap. my thoughts is if you want 400 whp, start with a new car that makes 400. at this point that's what i'd do...i'm at the point where i just want my cars to work, not tinkering all day every day...unless it's a project.

[coco26]

You'll want a higher flow cat to get past 280-ish hp. This is pretty much the line where the $/hp ratio goes downhill though. You'll probably spend 600+ on a catted J pipe and about the same on a cat back system, all for about 20ish extra hp.

 

I have the invidia catted J pipe, magnaflow cat back, aftermarket BPV, and tune and reliably make 290-300. The magnaflow cat back is one of the quieter options.

[Scubaboo]

I think it would be good to start with "stage zero" - get all maintenance up to date first.

 

From there your tuner of choice can log to establish baseline and assess for any problems and overall health of your motor, then tune for your agreed upon goals.

[FLlegacy]

I would start with finding a jpipe they are very hard to find now, and you need it catted unless you already have a tuner that will do it catless, most won't anymore-my local tuning guru gave it up altogether when the EPA fines started.

 

There are very few quiet aftermarket options, and the ones most recommend sound pretty much like the honda down the street with a fart-can. Your best bet is a good exhaust shop and a custom system.

[dwallar]

Thanks again to all of you who offered your best advice. Here's what I've decided to do. I contacted my tuning shop and they are a very reasonable bunch. They recommended a conservative approach. Firstly, on Monday the car goes in for a full diagnostic. They want to do a snapshot of where the car is at before doing any work. Also, they want to be sure there aren't any underlying major issues that would suggest to NOT do any tuning. Assuming all is well, we are going with a Cobb Access Port, Invidia catted J-pipe and a tune. That's all. They will check the bypass valve and only upgrade if it is leaking. He did say that the pipe is on backorder and will take up to a couple months to get. So that's where we are at. I am happy and more importantly I think I'll be happy with these conservative changes.

[whitexc]

That is a sound approach.

 

Sent from my SM-G996U using Tapatalk

[creep_nu]

i like the thinking...keep it conservative. if something blows up for some unknown reason and you want to take and build the engine and go for the gusto at that point, that's a whole other story, but for a solid daily driver a full exhaust and tune will get you to a good spot. plus, this leaves you more money for sway bars and konis and lowering springs and light wheels and sticky tires and aero and.....the list goes on.

[dudemonster]

Concur, that’s a good plan. At some point, after or during your adventure bumping up the power side, consider handling. A stiffer rear sway bar and other suspension improvements really help use and enjoy the power gains you’re seeking to achieve.

[dgoodhue]

BTW The bypass valve will leak at over 12psi. The Turbo can still create 17-18psi if the tune requests it, but it just won't be as efficient in doing it.

 

I think you are going about it right way. I did the Cobb AP, bypass valve, and Invidia Q300 catback exhaust. I was pretty happy with how much a difference that made. I installed a 3 port EBCS (at the request of my tuner) and had it Dyno tuned. I was happy with the car at that point.

 

If I want more acceleration, I would have done a catted Downpipe, TMIC, and STI exhaust cams, and bigger turbo in that order.

[coco26]

A tip for the first time tuning these cars - In the short hose that connects the intercooler outlet to the throttle body there are two rubber flaps that will cause you problems if not removed. They essentially flap open and block the airflow with increased boost.

 

Perrin sells a replacement hose, or you can just remove them from your stock hose.

 

Like dgoodhue said, the bypass valve will almost definitely leak. I have this one and it works perfect: TS-0203-1223

[FLlegacy]

If you get it tuned with the stock bpv you shouldn't need a retune to change it out, unless the stocker WAS leaking. The throttle body coupler is also a good mod if it hasn't been done by the previous owner.

[deedadoo]

You'll want a higher flow cat to get past 280-ish hp. This is pretty much the line where the $/hp ratio goes downhill though. You'll probably spend 600+ on a catted J pipe and about the same on a cat back system, all for about 20ish extra hp.

 

I have the invidia catted J pipe, magnaflow cat back, aftermarket BPV, and tune and reliably make 290-300. The magnaflow cat back is one of the quieter options.

 

Would you happen to have some sound recordings of your setup? I'm really interested in doing something similar, but don't want a drone or be too loud.

[coco26]

Sorry don't have any sound clips. Might get some in the future but have to fix a few exhaust leaks first...

 

There's not too much drone with what I have. I prefer sound quality over volume, so I actually added a vibrant muffler near the middle of the car (and forgot about it until just now). From what I can remember, the drone wasn't bad but it was obviously more than stock. Volume wise, cold starts (less than 50F) can be a bit noisy, but once its warm, idle is near stock volume. Under load, I'd estimate its still quieter than some factory exhausts these days, but I've never let anyone else drive it so I don't actually know.

 

Next time I start it I'll try to get a clip of some revs.

[Scubaboo]

Concur, that’s a good plan. At some point, after or during your adventure bumping up the power side, consider handling. A stiffer rear sway bar and other suspension improvements really help use and enjoy the power gains you’re seeking to achieve.

 

I second this. I have an AVO downpipe, RacerX TMIC, GFB bypass valve, Grimmspeed 3 port BCS, etc...all gathering dust because after all the handling stuff I am just so satisfied with it that more power went to the back burner lol!

 

Funny I'm all set for power, I already upgraded cooling with an aluminum rad and STI thermostat, I put on gauges for boost, coolant temp, oil pressure/temp in preparation.

 

So OP do consider suspension mods, really makes it a nice all around ride especially with more power like you are planning.

[coco26]

+1 on that as well. You can get a koni shock setup for the same price as a downpipe, and they do way more for the car than the downpipe would.

[DrD123]

a larger front and rear swaybar to accompany the Konis makes a big difference, as well. (though the front is a bit of a bear to do if the engine isn't out of the car for something like, say, a new shortblock... but then it just drops right in... )