I recently had an Alta 3" catback installed on my car. Sounds great! However, I have lost about 2-3psi of boost and slower 1/4 mile times. I watched them put it on and saw no potential issues. There is no indication of leaks that I can tell.

I have a CAI and the catback. All the gain I saw from the CAI are lost with with catback addition.

I was expecting a gain... not a loss... Any suggestions?

 

Are you measuring boost with a gauge or data logging?

How are you determining you lost power, on the drag strip with a timing sheet or best clock time on a private/quiet 1/4 mile?

Did you keep the 2nd cat and resonator?

If it is not leaking, has your ECU adapted? Options take it off and see if you get your power and boost back.

Put a 2.5 pipe on the MINI and keep the Alta muffler.

Lots of variables, only real way to know if you lost power is to put your car on the dyno and do before and afters.

Don

 

I have a boost gauge.

My best time Before was 15.00. After catback fastest 15.19. Average the last night was 15.25. Done at a drag strip. (I still have the original run-craps on)

Does it take time for the ECU to adapt?

 

If you have driven with the new cat for a day, your ECU should be adapted.

Do you have any idea of HP/TQ before the addition of your new exhaust?

If so, you might want to find a dyno and see what your getting now.

Most people report gains, but some down low torque loss, that might be why your seeing lower trap times.

You might have to adjust your launch style. And get rid of the run-craps.

 

Starting to think a 3inch system is too big for the MINI!

 

I hate to say it but when I put on my 3 inch cat-back I also felt like it lost power. No stats though

 

I'm convinced after much research and speaking with professionals that owning the "first 3 inch exhaust on the market" really isn't cracked up to what it's suppose to be.

In the coming months, I'm going to purchase a 2.5 system, either from Hector or Riss, once details on dyno's come back for both.

 

ya I know I am thinking the same thing. But then I will probably get a bigger turbo. So will I need it then?

 

Nope. I too will be getting a bigger/hybrid turbo eventually. M3This made a good point in his Riss thread.

Cars that are more powerful than the MINI, cars that have bigger turbos, or larger displacements, don't have full 3inch systems from the factory. It's not needed and is indeed overkill. The Evo is a good example.

As soon as some numbers become available, I'll make my decision. Riss for his excellent rep and top notch quality parts or Hector with his great sound and top notch parts.

Anyone in the market for a way marked down Turbo Back??

 

3" may be overkill but does no harm. It should perform no less effectively than 2.5"

I agree though that a cat-back exhaust on the MINI doesn't do much. Dyno tests have verified that even though you get a measurable gain from an open intake OR cat-back exhaust, there seems to be no additional power when both are combined. I also experienced a little throttle lag when I had both the Alta intake and turboback exhaust. I'm back to the stock airbox with an Alta panel filter and a custom exhaust using the Alta catback.

The real bottle neck in the exhaust system is the center section. At the bottom of the DP, the pipe diameter is 2.25". It then varies between 2.25" and almost down to 2" at spots through the center section where it is crush bent to go under the front sub frame then into the second catalyst.

I just had a custom center section made locally here that widens the pipe to 3" starting right at the bottom of the DP, and goes as straight as possible to the Alta cat-back, deleting the second catalyst. This has made a huge difference. I had the full Alta turboback for awhile and took it off both due to loud droning and CEL's. I'd say I have 90% of the power of a full turbo back system but no droning and no CEL's. The car sounds slightly louder during regular driving but at WOT around 4K RPM it turns into a really throaty growl. I love it! It's all I could have hoped for.

Just my 2 cents derived from a few years of costly experimenting...

 

Finally found a description for what I'm dealing with. You said "throttle lag" and with my ALTa, I feel the same thing. I need to either get a new system or customize the one I have. Depending on funds and the new iPhone dropping a new system will most likely be in the works, sometime this summer...

 

I know the feeling of throttle lag all too well. I'm surprised you are still experiencing it with the tune. I would have guessed that would counteract it. I still believe, even though it may have been induced by starting to open up the exhaust, that it's at least partially being caused on the intake side. If possible, before you spend a lot of money, try putting the OEM airbox back on just to see how it feels for a day.

 

I found this article on getting more power out of the new WRX

http://www.caranddriver.com/reviews/...u_wrx_gear_box

their findings about adding the intake or the exhaust, then the problem they found after adding both reflect my experience with the R56. A tune should fix it, but maybe RMW's isn't totally dialed in yet, or maybe it's just something you have to live with when you totally open up the airflow.