Cobb AP & Cobb DP

[renoguy20]

Anyone here have the Cobb AP? Would you recommend it? I have the Perrin catback, and an AEM S/R intake (will ditch that and gett knn panel soon). Also any suggestions for brand of downpipe? I looked at Cobb's and liked it because of the included cat. Does anyone know if (with that dp) the car will still pass emissions? Should I get the DP first and then look at the AP. Any suggestions, comments?

[MikeK]

I have and can recommend both. I would go for a custom tune though, rather than the off the shelf maps from Cobb. They work perfectly for some people, not so well for others.

[Kevin M]

You can pass emissions without a cat actually- if you get the CEL turned off with your reflash, be it EcuTek or Cobb, and take it somewhere that won't bother looking for it. Cobb's hard parts are high quality, and for the record I'm always in favor of keeping a cat in the exhaust. If you do go with Cobb stuff, give Aaron a ring at Subaru Specialists. He can hook you up with the parts, arrange installation, and talk about custom tuning options.

[MikeSTI]

Cobb down pipe if you want a cat, Perrin (split waste gate) or Invidia (bell mouth) if you dont want a cat - Kevin is correct as long as you plan to live in Nevada you should pass smog with either unit. However I would not expect it to last forever as the state will at some point add a sniffer test to the check. At that point the Cobb sounds better.

[cody]

I'm pretty sure the the Crucial DP I have is less expensive. Also it's divorced wastegate, high quality stainless steel, high quality ceramic coated, lifetime warrantied. My tuner was very impressed with my turbo response. I also have their uppipe which is really nice as well. It's a shorty DP so you retain your 3rd cat. The 3rd cat is not that much of a restriciton to justify replacing it with a high flow cat IMO.www.crucialracing.com

Also, I agree with getting a custom tune. The AP is really nice. Try to take advantage of the package deal where you get the car protuned including the AP for $700...I think it is. I'd get an UP too.

[renoguy20]

Is an uppipe really worth it on an 05 (i heard there isnt a pre-cat in the uppipe of that year). Plus the crutial dp mentioned retains the stock midpipe (3in dp + 2 1/2 mid + 3in catback?). Id rather have 3in all the way back (that will maintain better velocity?). (also upon visual inspection , which just about all smog stations will perform, the absence of a cat will fail your car).

[cody]

I'm 99% sure that all WRX's have a cat in the UP while all STI's do not. Regardless, some STI owners have even put in Crucial UP's since they're ceramic coated. But I don't know how great of an investment that is. I've seen a guy with an STI sware his turbo spooled faster with it, but who knows for sure. But for a WRX, I totally recomend an UP.

I run exactly what you described, "3in dp + 2 1/2 mid + 3in catback"

IMO, if you're going to stick with the stock turbo, the stock 3rd cat won't be much of a hinderence. Basically the difference between 3" all the way and running the 3rd cat is about 5-10 whp.

You could run a cut-out or swap in a racepipe for racedays if you wanted. Hell, you could even get an extra map on your AP for a racepipe and race gas. There's endless options.

For a smog check, PM me and I'll tell you where to go.

[Kevin M]

Since a 3" turboback with aftermarket cat is as legal in Nevada as the stock midpipe, I'd replace it all. Same for the uppipe- your stocker should have a cat in it.

[MikeK]

Originally Posted by BAN SUVS

Since a 3" turboback with aftermarket cat is as legal in Nevada as the stock midpipe, I'd replace it all. Same for the uppipe- your stocker should have a cat in it.

Actually, my understanding is that smog laws are federal, it is just the tests that differ from state to state.

[cody]

I can tell you that it's against federal law to tamper with any of your cats. I think after your car has somthing like 60K miles, you can replace the cats with new ones if they've gone bad.

But, you're right, testing is done by the state. For instance, the sniffer test they do in CA is all mandated by the state.

Keeping the stock 3rd cat, I know of a couple guys who have passed PA sniffer testing.

[sperry]

Originally Posted by cody

I'm 99% sure that all WRX's have a cat in the UP while all STI's do not. Regardless, some STI owners have even put in Crucial UP's since they're ceramic coated. But I don't know how great of an investment that is. I've seen a guy with an STI sware his turbo spooled faster with it, but who knows for sure. But for a WRX, I totally recomend an UP.

IIRC, the up-pipe cat is a crazy expensive cat developed by GM and used by Subaru as part of the old GM/Subaru partnership. It's because of that cat that the WRX was finally able to make it to the US, since it allowed the WRX to pass cold-start emissions in CA.

However, in the '06 (IIRC) the up-pipe cat has been replaced with a much cheaper air-pump system that adds fresh air to the exhaust stream allowing the down-pipe and mid-pipe cats to work more efficiently so the car will still pass CA emissions tests.

As far as the benefits for an up-pipe: if the up-pipe cat were to break in anyway on the WRX, there's a good chance the bits would destroy the turbo. Plus as Cody and others have mentioned, an aftermarket up-pipe on '02-'05 WRXs help spool on the turbo quite a bit. I'm not so sure about how they'll work on the new '06.

[cody]

Originally Posted by sperry

...if the up-pipe cat were to break in anyway on the WRX, there's a good chance the bits would destroy the turbo. ...

Good point. It's also good to get the EGT sensor out of there since it's only there to prevent hight EGT's from destroying that cat. Once you remove the UP cat, it serves no purpose and is also a potential hazard if a chunk breaks off.

[sperry]

Originally Posted by cody

Good point. It's also good to get the EGT sensor out of there since it's only there to prevent hight EGT's from destroying that cat. Once you remove the UP cat, it serves no purpose and is also a potential hazard if a chunk breaks off.

Yep, I got a bolt in my up-pipe, and a resistor in the sensor socket to prevent CEL's.

[AtomicLabMonkey]

Originally Posted by cody

I can tell you that it's against federal law to tamper with any of your cats. I think after your car has somthing like 60K miles, you can replace the cats with new ones if they've gone bad.

From Dynomax's website:

In August 1986, the U.S. Environmental Protection Agency (EPA) issued new proposed guidelines for the construction, efficiency, and installation of aftermarket converters. The EPA guidelines state that replacement converters may be installed only in the following situations:

1. The vehicle is missing a converter.
2. The state or local inspection program has determined that the existing converter needs replacement.
3. The vehicle has exceeded the age or mileage conditions of the original equipment catalytic converter. Consult vehicle owner’s manual or emissions warranty manual for specific details on your vehicle. Additionally, a legitimate need for replacement has been established and documented.

The installer must include the customer’s name, address, and the make, model, year, and mileage of the vehicle on the service invoice, along with a stated reason for replacement. Where a state or local government has determined that a converter is damaged or needs replacement, the service or repair facility must retain a copy of the written statement or order by a proper government representative which indicated that the converter should be replaced and attach it to the invoice. Where the replacement need has not been verified by a proper state or local government representative, the customer and a representative of the service or repair facility must sign a statement verifying that replacement is justified. That statement is included in every Walker converter carton. Furthermore, the EPA has issued the following installation requirements:

1. The converter be installed in one of the three situations outlined above.
2. The converter be installed in the same location as the original converter.
3. The converter be the same type as the original converter (i.e. oxidation, three-way, or three-way plus oxidation).
4. The converter be the proper one for the vehicle application as determined and specified by the manufacturer.
5. The converter be connected properly to any existing air injection components on the vehicle.
6. The converter be installed with any other required converters for a particular application.
7. The converter be accompanied by a warranty information card to be filled out by the installer.
8. Federal law prohibits removal or replacement of properly functioning O.E. catalytic converters.
9. Not for installation or use on 1996 and newer vehicles.

[MikeSTI]

8. Federal law prohibits removal or replacement of properly functioning O.E. catalytic converters.

thats why I didn't replace mine my cat is still attached to the rest of the factory piping.......

[cody]

Nice loophole.

[sperry]

Originally Posted by MikeSTI

8. Federal law prohibits removal or replacement of properly functioning O.E. catalytic converters.

thats why I didn't replace mine my cat is still attached to the rest of the factory piping.......

Nice work.