HELP: Spec-B Turbo Back Exhaust Upgrade

[b18b_turbo]

check link for product:

http://cobbtuning.com/products/?id=3401


I'm upgrading my Legacy just Turbo Back Exhaust and ECU retune....


Will this Turbo Back Exhaust work on my Spec-B?

I'm looking around for one of these to buy but only finding it here (link above) which is an American company....The GT in America is a 2.5T engine while the JDM Spec-B is a 2.0T. Mind you, the American GT does less hp than the JDM spec-B


Q: Would this upgrade be different from the JDM equivalent? I am thinking that the exhaust upgrade should be the same, but i need a professional opinion.

Also, would the geometry of the piping be different in the USDM? Or is it the same?

[Alpha_2nr]

Piping runs for a catback should be similar. Differences (if they exist) may lie in pipe lengths etc, due to the USDM having more flanges and whatnot.

This is why, e.g. a USDM STi catback is about 4" longer than a "pure" JDM STi catback.

Other than that, you may need to double check what turbos are used.

Mind you, the American GT does less hp than the JDM spec-B

And....you should also realise that the engine is a bit detuned in the USDM model, to make a clear cut difference between the Impreza STi and the Legacy GT.....from a market standpoint.

[b18b_turbo]

Knight1, thank you very much for that very helpful post.

Would you or anyone have a map of the exhaust system in a Legacy Spec-B? It would be helpful to email it to the company and have them take a look at it.

Other than that, you may need to double check what turbos are used.

The dealer told me that it is TWIN TURBO, but I am yet to check that for myself, i did not get time to go remove the plastic covering over the engine. I will also have a field day finding everything as i am new to the scooby camp. The turbo(s) should be located somewhere below the Intercooler right?

[Alpha_2nr]

The dealer told me that it is TWIN TURBO, but I am yet to check that for myself, i did not get time to go remove the plastic covering over the engine. I will also have a field day finding everything as i am new to the scooby camp. The turbo(s) should be located somewhere below the Intercooler right?

At the risk of making another "helpful" post.....

Your car doesn't have a twin turbo. That stopped with the previous model Legacy. Newer GT's and SPec B's carry a twin SCROLL turbo. It's a single turbo...with a different turbine design as used in newer Imprezas....v.s. to say...a "regular" turbo.

IIRC the stock GT JDM uses an IHI VF38 turbo. I'm not sure whether the Spec B carries a different turbo....I doubt it does. That should help COBB determine whether it can work. You should confirm this with say...something like a UK Legacy owners forum or something.


As for the location of the turbo....I think Polydor made a post with the "basic layout for a Subaru engine bay".

That should help out.....engines are practically identical.

[Maserati]

b18b_turbo,this is the diagram from Polydor's post
http://www.subaru-impreza.org/images/vi ... ne/1-7.htm

[b18b_turbo]

Thanks fellas!

The turbo is where i thought it was....thanks Maserati

i will post in a UK forum also but can anyone source specs on the JDM turbo back exhaust and the equivalent USDM specs? These things are so hard to find!

I know it should be the same, but u never know, ESPECIALLY for exhausts in the US as a result of strict emission laws.