My 2008 Non-s has 186000 miles on it. I was getting ready to replace my oil filter adapter gaskets for the 2nd time and when I removed the exhaust manifold cover, I found that my exhaust manifold was cracked where the runners come together. Refusing to pay for an OEM assembly for over $1400, I bought an OEM replacement from Magnaflow. What I found is that the opening from the runners to the catalytic converter is smaller than a golf ball. The Magnaflow is larger than a tennis ball. Not only that, but the runners on the original manifold were 1 inch and squeezed down to 1/2 inch as it enters that narrow throat into the converter. The Magnaflow had tubes that are 1 1/2 inch and enter like a collector on a header. After reassembly, the car is tremendously different. Deeper exhaust tone, smoother idle, and much more power and torque everywhere. My suspicion is that Mini has deliberately cut the power down to warrant stepping up the a Cooper S. Today with 4 people in the car, the car felt stronger than ever. If you want to add power to a Non-S, install a Magaflow OEM replacement manifold cat assembly. You will not be disappointed in any way!

 

 

In comparison with the Justa manifold? The S manifold has a boss on one end that the Turbo bolts to.

 

Can you post the Magnaflow part number. Their site says underdevelopment.

Thanks

 

Here are the before and after pics. The Magnaflow part number is 553028. I truly think I have picked up over 20 hp. The car feels incredibly quick, even with 4 people in it. If you ask me, this was a deliberate plan by Mini to create distance between the Cooper and the S.

 

Here they are laying side by side

 

The improvement in airflow looks considerable! I may do this.

 

If it is moving more air, does the mixture need to be adjusted?

 

No, I installed it with everything else stock except for a K&N air filter and a sprint booster, and the car responded so good, its almost like a dream. I would not be surprised if I gain 20+ hp and torque. I gained almost 3 mpg, and this car pulls so strong now. It feels like it wanted this all along. 4 people in the car and climbing a long hill, is no issue at all. The car actually gains speed with part throttle, not even WOT. Not only that, but I find myself have to retrain my driving. The car wants to settle in at 90mph, and I have to consciously lighten my foot on the throttle. It is an absolute win!

Ivan

 

Is there a catless option? I kind of hate the environment.

 

No, they didn't have a listing other than this one. I even called them to see if they had dyno numbers since this unit is obviously seriously better than OEM. They said they did not dyno test the unit. I found that interesting since you can see how much better this unit is. I imagine if you buy a catless header it would be the same as this without the cat. It seriously looks like a header with a cat attached.

 

You have a sprint booster. What does your Mini feel like with the new manifold and the booster disengaged?

 

I'll try it tomorrow and let you know.

 

Ok, without the Sprint Booster, the car still pulls stronger than it ever did. I will say the car is quick. It has to be around 145 hp to feel the way it does. I also am up 2 mpg and that is with not being easy on it. I find you drive with less throttle angle to maintain speed now. This is an amazing transformation!

 

An update. All smiles! This car is transformed. I just came back from a 700 mile ride. The car climes hills without downshifting. Accelerating onto a highway is awesome! Driving freely on this trip I got 36.9 average mpg in one direction and 36.1 mpg in the other. That is with long sweeping hills as you go up into New England. I think if I was able to restrain myself, 40 mpg is not out of the question. The exhaust sound through the stock exhaust is fantastic and laying into to get through a yellow light make it sound like a very refined engine. Idle is smooth as glass too!

 

 

The Sprint Booster is an amazing device. People on this forum bash it because it technically doesn't add horsepower, but the throttle lag diminishes tremendously making the car faster. Everyone who has a Sprint Booster totally loves it. Installation is very easy. You simply need to remove 2 screws that hold the gas pedal to the car. Unplug it, install the Sprint Booster in between, plug everything back in and your done. I will never, not have, a Sprint Booster on this car. It simply makes the experience better. I have never wanted to upgrade to a S because of it, and now with my new manifold, I never will give this car up for a turbo Mini, this car is beyond entertaining to drive now.

 

 

I think my car picked up 25-30 hp from the manifold. Tremendous gain. That being said, tuning may be possible now that the car is breathing better. The original manifold drops down to a golf ball size entering the cat. With that in place, there is nothing to gain. With it enlarged to the size of a tennis ball, that can be very different. I noticed I can use the race mode on the Sprint Booster, which would not give me anything before the manifold swap. That tells me there may be something to gain. Maybe even through a cold air set up that will flow more intake air. I found years ago a aftermarket turbo for the N12 engine. I never was able to get feedback on that. My plan was to pursue it when my engine fails, but at 188,000, I am not expecting that to happen anytime soon.

 

 

The Magnaflow unit fits like OEM. I have it attached to my stock cat back system and I love the way it changed the sound. Much deeper. With the stock manifold, I never felt a gain using race mode on the Sprint Booster. Sport mode on top of the the normal mode of the Sprint Booster felt awesome. Now I can feel a positive gain from Race mode. Normal driving is still crisper with the Normal Sprint Booster mode, but Race mode now makes a difference. I have a K&N in the stock air box. I don't know if I want my WOT sounds louder than it is now. To me, it sounds perfect now. I have the silencer holes in the stock air box blocked off.

 

 

I would expect that to flow marginally better since it will have less material in the cat due to Federal Emissions. Since you do not have California emission requirements, that would be the one to buy.

 

Just adding an update. The car is spectacular. It is so strong. I am installing a DDM intake next week and I am beginning to think about having it tuned. Think about it, no performance gains on these cars with tuning, because they are still being restricted when the tuning session is going on. Tuning with a free flowing exhaust may yield something interesting.

 

Sweet. I’ll be getting the K&N typhon, and those headers once I have Enough money saved up. And eventually find someone to tune the car for me see what we can get, and maybe delete one of the cats. It’d definitely be interesting and I’m curious to see what the power gains will be. And well maybe increase the rev limiter from 6500 to somewhere between 7000-8000.