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Old 09-25-2012, 12:59 PM   #1
Sir Tolik
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At the Track do I really need a 3" exhaust?

Good evening! (or propably morning on your side of the world )
Having driven my car for 3 years, I finally felt the need to tune something, so bought the OP2 and the wideband sensor.
I would like to have better response / more power in the middle range of the revs mostly for city driving plus drive on curvy tracks or frozen lakes.
The car is fully stock except for the forged pistons. The exhaust has the catalists in it.
So the questions are:
1. If I am not planning to change the turbine in the nearest future, do I really need to install a 3" exhaust from the turbine?
2. How much peak boost I can get and does it require to chane the fuel pump?
I do suppose that some similar questions have been discussed and gonig throught the search results, but so far did't find nothing particular.
Thank you in advance!

I also had am idea to only install a catless 3" downpipe (Perrin or Invidia, may be), in order not to damage the stock DP when installing the O2 sensor, but I was told that there will be some connection issues with the stock exhaust. Is that correct?
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Last edited by Sir Tolik; 09-25-2012 at 01:12 PM.
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Old 09-25-2012, 01:12 PM   #2
wrxlaunch
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By OP2 do you mean Access port v2?
As for the exhaust, to gain some hp... you will need to remove/replace the restrictive oem cat with something more free flowing.

If it is the AP V2 that you have, please read map notes and recommended parts list on Cobb's website
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Old 09-25-2012, 01:14 PM   #3
Sir Tolik
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I meant the Tactrix OpenPort 2.0. I think there are no notes with it regarding exhaust, unfortunately
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Old 09-25-2012, 01:27 PM   #4
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If you're not sure how to answer those questions, you probably want to either read up a lot more or get someone to tune your car.

You already have the cable, so I would recommend the second option. E-tuning is very effective, and even though you're in Russia you can get tuned by someone in the States very easily.

Try Phatron on here, I've heard good things about his e-tuning.
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Old 09-25-2012, 01:40 PM   #5
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You don't need a 3" downpipe, but you do want one without cats in order to raise the midrange boost.
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Old 09-25-2012, 01:58 PM   #6
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How are you going to tune it with the Tactrix cable? I assume you're paying someone to do it? I would at least get a downpipe. The cat isn't really the issue, it's the connection to the back of the turbo. You want something with a bellmouth or divorced wastegate path (nearly all aftermarket downpipes have this). You don't really need a new cat back exhaust at this point. You should be able to research which downpipes will work. Just about any of them should be fine if you use the GrimmSpeed adapter.
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Old 09-25-2012, 02:44 PM   #7
Sir Tolik
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Quote:
Originally Posted by xluben View Post
How are you going to tune it with the Tactrix cable?
No, I don't pay to anybody. Using the advices from the romraider forum and my friends involved in tuning I am playing with the ROM. For myself I want to decide whether to install the wideband sensor into the stock downpipe or to buy a 3" one. It seems that at this stage I will select this option and then decide what to do next. Didn't know about Grimspeed - seems to be a perfect solution for me at this point, thank you!

Last edited by Sir Tolik; 09-25-2012 at 02:54 PM.
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Old 09-25-2012, 02:55 PM   #8
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Quote:
Originally Posted by Sir Tolik View Post
No, I don't pay to anybody. Using the advices from the romraider forum and my friends involved in tuning I am playing with the ROM. For myself I want to decide whether to install the wideband sensor into the stock downpipe or to buy a 3" one. It seems that at this stage I will select this option and then decide what to do next. Didn't know about Grimspeed - seems to be a perfect solution for me at this point, thank you!
I saw that Cobb / Perrin 3" downpipes have catalysts. Do they create some problem?
These cats are of the "high flow" variety and will have negligible impact on your power potential. That said, unless you are required to have an emissions inspection on your vehicle, catless is cheaper.
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Old 09-25-2012, 03:11 PM   #9
Sir Tolik
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Quote:
Originally Posted by mechatricity View Post
These cats are of the "high flow" variety and will have negligible impact on your power potential. That said, unless you are required to have an emissions inspection on your vehicle, catless is cheaper.
Well, I don't expect emission control in the nearest future. So will search for cheaper alternatives. In the Internet the catless perin downpipe is mentioned. Where do they come from? Just talked to Perrin - they sell only DP with cats...

Last edited by Sir Tolik; 09-25-2012 at 03:41 PM.
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Old 09-25-2012, 07:37 PM   #10
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Check out the torqued performance maps for open port. They're reliable with a nice power increase and smoothing of the power band. Eric can also help you fine tune it for your application.
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Old 09-25-2012, 07:50 PM   #11
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hey sir tolik i am running a tsudo catless downpipe which i bought for 180 bucks brand new and its been awesome so far. clean wells and mounts up perfect! Also look at the invidia catless downpipe! and i second what wrx border says. I'm running one of erics maps and its top notch stage 2 + is very strong and responsive for just a tune and basic bolt ons! good luck sir tolik
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Old 09-30-2012, 09:16 AM   #12
Sir Tolik
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Thank you for the advices. I am mostly targetted for Invidia now (as there are not too may choises here), but also I was adviced to buy this one:
http://race-shop.ru/product_info.php?products_id=8
It's hand made by one of the tuning shops in Moscow. The price is about 450 USD. What do you think of it?
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Old 09-30-2012, 06:27 PM   #13
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Is the stock STI down pipe the same as the WRX down pipe ??? interchangeable ???
Id like to gut one and run it. Stealth ...
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Old 09-30-2012, 07:04 PM   #14
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I like my cat-less Invidia downpipe
also $450 USD sounds a bit much for a cat-less downpipe, but I don't know how conversion rates would take part in that.
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Old 09-30-2012, 11:26 PM   #15
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You can get a Catless downpipe for 70 on eBay. I got one and it sounds awesome and cheap
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Old 09-30-2012, 11:36 PM   #16
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Love my Invidia!
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Old 10-01-2012, 05:14 AM   #17
Sir Tolik
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Quote:
Originally Posted by rocketperson7 View Post
I like my cat-less Invidia downpipe
also $450 USD sounds a bit much for a cat-less downpipe, but I don't know how conversion rates would take part in that.
Taking into account how much does a piece of pipe cost I find it extremely expensive. Catless Invidia costs about 390 USD here. The main question is whether I will get any reasonable benefit for paying additional 60 USD for a fully splitted downpipe comparing to the Invidia one.
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Old 10-01-2012, 06:37 AM   #18
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The divorced wastegate downpipe you have linked seems like a very good option for a catless downpipe. I have had the Perrin 1 piece and now have the 2 piece with 2 cats in it, and also run Invidia Q300 cat-back exhaust. It opens up the car's potential a lot. You will find that the stock turbo runs out of steam long before you will need a new fuel pump or injectors, so you would be fine with a basic stage 2 tune. Torqued Performance is one of the best online (E-tuning) options out there.

You don't need full 3" turbo-back exhaust for extra power. Just a tune will give you a nice new kick to your car. The downpipe is the most restrictive part on the vehicle with the 2 catalitic converters, but will also make it quite a bit louder.

Once you start modifying your car, there is no end to it... So make decisions you are prepared to live with
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Old 10-01-2012, 06:46 AM   #19
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I have a pretty much new (used for 1500 miles, sold my wrx) divorced bellmouth invidia catless downpipe. And if you have a stock catback I have a grimmspeed 3in downpipe to stock catback adaptor. Check out my for sale add. I'd let them go together including all gaskets for 290$
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Old 10-01-2012, 07:55 PM   #20
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You may be more likely to experience increased boost creep going with a catless dp over a catted one.
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Old 10-02-2012, 11:52 AM   #21
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He has an 07 STI according to his profile. So no OTS Torqued Performance maps will apply. Still, you could probably get e-tuned from Eric of TP. And I would definitely get a DP before you start messing with tuning.
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Old 10-02-2012, 12:37 PM   #22
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A different option is to get the flanges for the downpipe and have a shop over there make you one. Since you don't need cats, it may be cheaper going this route.
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Old 10-02-2012, 04:04 PM   #23
Sir Tolik
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WRX boarder - well I hope I am prepared for them
ecbmxer - I am waiting for installing the DP in order to install the wideband sensor, because the EGT at 4 speed full throttle can go up to 950 degrees, so any tuning without knowing what's happening can be fatal
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Old 11-15-2012, 04:22 PM   #24
Sir Tolik
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Well, the idea of buying an Invidia DP in USA and shipping it to Russia actually failed - the shipping cost came out to be more than 100$, so it's easier to buy something here...
Is the quality of DP's with the price of 100-150$ worse than of Invidia? Most of the producers, which can be found on ebay, are not even known here

Last edited by Sir Tolik; 11-15-2012 at 04:47 PM.
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Old 11-15-2012, 05:03 PM   #25
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It may be cheaper to see if an exhaust shop over there will make a custom one for you. The shop that you listed seems a bit expensive for just a catless downpipe.
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