Miata Turbo Forum - Boost cars, acquire cats.

- Insert BS here (https://www.miataturbo.net/insert-bs-here-4/)

- - The Dedicated URABUS Thread (https://www.miataturbo.net/insert-bs-here-4/dedicated-urabus-thread-78090/)

Is going catless a drastic difference? I can never decide if I want to go catless, but if I do I'm definitely getting that DP. Doesn't seem that expensive either.

Mostly paranoid of getting pulled over/state ref'd/any of that shit.

drastic power difference? no

Yay it finally came out. When my gop-seed finally dies badly enough its not worth salvaging I'll snag one of those. Until then welding up the odd crack every couple years on the $90 gods-peed makes the most economical sense.

Quote:

Originally Posted by 18psi (Post 1301953)

drastic power difference? no

I'm assuming it improves spool.

Quote:

Originally Posted by 18psi (Post 1301953)

drastic power difference? no

Really?

On the BRZ, that's basically where all the power comes from on a header swap is ditching the primary cat. All the headers (with the exception of ACE/JDL) all make about the same once ditching the cat, around ~10whp.

I would have assumed more so on an FI car. I know the 135/335i's make huge power with a downpipe and tune.

A catted down pipe has a high flow cat so it's not the same as the stock restrictive cat the difference between the two is maybe 5 hp on a high-power application , >350

Couple different things going here...

OEM header and OEM cat vs aftermarket header and aftermarket 200-300 cell cat
aftermarket header and aftermarket 200-300 cell cat vs aftermarket catless header

(Feel free to exchange the word 'header' with 'downpipe' in either of the above examples)

I'd venture a guess that OEM -> aftermarket anything is going to see a significant gain, the differences between aftermarket products? Probably not so much.

Yeah, oops I forgot to specify I meant between the OEM downpipe and the catless grimmspeed one. I assumed it was like maybe 40 hp and dramatically improved spool.

the difference in oem to aftermarket down pipes is drastic, with tuning. aftermarket vs aftermarket, not so much (with a few exceptions, like the non-bellmouth hks piece of junk)

The difference between OEM and aftermarket unequal length headers is very small as well.
A properly designed equal length, on the other hand, works wonders with tuning (killerb/fullrace/etc)

All of this on Ej, I'm no expert with the twins and their n/a mumbo jumbo.

Yep! I'd really like to get a catted dp, but I'm waiting for a decent one to pop up used somewhere. First i want to do an upipe and axleback, then maybe downpipe some time later. :party:

Do up/dp together cause same amount of work ;)

Well after 5 years of ownership you can finally add me to the 5x100 wheel bearing club. My left rear started getting loud a few weeks ago at right around 90k. Getting that damn long bolt removed was utterly impossible since it had fused to the bushing sleeve and they just spun inside the rubber after breaking the bond with a cheater bar. One sawzall blade, a new $20 OEM bolt, and 2 new outer bushings later she's nice and quiet again. The HF bearing press kit worked like a charm for the R&R once I had everything apart.

Quote:

Originally Posted by 18psi (Post 1301690)

come buy my 2013 WRX with 15k miles for 20,500 :)

Hatchback?

Serious? that would probably go for $23000 here. Or at least that's what it would be listed for on CL.

Ugh.

way too nice for me. I'd ruin that car. haha

Gents, it's cheap cuz it's a rebuilt title.

Not that it takes anything away from the CAR, but it does take away from the PRICE.

Yep, the car is tip top. All the parts are original, all the paint is original, nothing was repaired or repainted, but front bumper, fender, and headlights were replaced.

hence the part at the end where I encourage people to take it to Subaru or anywhere else and get inspected, and see what I mean about this thing being immaculate.

Comparing the car/mileage/condition to others, it's still much cheaper than most:)

Quote:

Originally Posted by 18psi (Post 1302313)

Oh yeah, obviously a very nice car. But that explains the lower price.

I licked it while I was in his garage, it tastes like peppermint.

https://www.miataturbo.net/attachmen...ine=1453750493

I met up with MartinezA92 on Wednesday at the NCR meet (:wavey:) and picked up his stock STI axleback. I got a chance to install it today and take a test drive.

The exhaust is wonderful. Rather than just sounding like any other car on the street, it sounds like what my brain thinks a Subaru should sound like. It has added a lot of low tone and it has juuuust a little bit of the Subaru rumble or boxer growl at idle and at low speed. No resonance anywhere that I can hear, and being that I have a wagon that was a legitimate concern. Cruising at 65-75mph the exhaust sound almost completely disappears into the road noise. Hard acceleration is not an issue. It sounds like an OEM performance exhaust, very adult. To be honest, I'm actually surprised its not slightly louder. I'm very glad it does not sound anything like the man-child exhausts that are so prevalent on Subarus these days.

Also, the internet was right for once. The stock WRX midpipe is 2.25" at the flange and appears to maintain that size all the way to at least the resonator. The stock WRX axleback section off my car drops down to 2" or possibly even as small as 1.9" about 0.75" downstream of the flange, and the bends are distorted. The stock STI axleback is 2.25" all the way to the muffler can and unlike the WRX, the tubing has smooth perfect mandrel bends throughout. My brain tells me that in all reality the STI axleback probably didn't add anything more than sound, but it gives me a warm fuzzy to know that I've eliminated that restriction from the system.

TL;DR: I really like the STI axleback. Two thumbs way up :bigtu: :bigtu: