The M2 comes with decent power from the factory without any modifications, but in the spirit of building my vision of an M2 GTS, I wanted to do a few things. Before I get flame mail from those that want huge horsepower cars....I acknowledge that the M2 is not the most powerful thing out there. But the power it does have is very balanced with the chassis. I am in the camp that believes you don't need 500+ hp to have a fast track car. With the right driver I have seen a Miata make a fool out of a Porsche or Corvette on the track. I believe that a good driver and a balanced car will likely lay down the fastest lap times. Stock the M2 has an inline 6 cylinder single turbo putting out 365 hp and 343 lbs torque pushing 3,450 lbs. Not bad for a short wheelbase car that is priced reasonably. The turbo has some lag but not much and often it is unnoticeable. On the track under hard pushing you can notice the turbo lag a bit, but you can compensate for it by spooling up the turbo a bit early.
At the time I modified for power there were not many options. No one had bigger turbos or bigger intercoolers available for the M2, so I opted for a cold air intake and a tune. For these kinds of mods I always go with Dinan as they are a trusted brand that make reliable products. I did not want to push the power too high as that often leads to other parts breaking or wearing out early due to the added stress or heat from the power mods. I wanted a bit more power but mostly more responsive feel in the power delivery that would not stress the drivetrain or cause maintenance issues down the road. I also live in CA and thus I wanted power mods that would pass CA's strict smog requirements. Thus Dinan was the first place I looked as they are one of the few that go through the trouble of getting CARB certified (at the time of this post they are still pending CARB approval for some of their power mods).
I got their cold air intake kit finished in carbon fiber as well as their stage 1 tune. The cold air intake adds some engine bay jewelry but also gives the engine a nice note when you rev it up. The stage 1 tune changes the signals going to the ECU that then "tricks" the ECU to make adjustments which results in more power and more responsiveness. That is an overly simplified explanation, but for more details check out their product pages.
The claimed gains for these mods are as follows, but I will be doing a dyno after the build is done to record actual power and weight changes. These gains are likely under ideal circumstances and thus I am a bit skeptical of how real they are, but what I can say is the car does have more power and responsiveness than a stock M2 and thus I am satisfied.
- Cold Air Intake: 10 hp peak gain, 15 lbs torque peak gain
- Stage 1 tune: 15 hp peak gain, 7 lbs torque peak gain
About a year ago Dinan did come out with a bigger turbo and intercooler package which would more dramatically increase power. The reason I have not gone this far with the power mods is that the balance of the car (the best part of the car in my opinion) might suffer. With gains of 101 hp and 86 lbs torque for Dinan's P2 Power Package I am not sure the car's chassis can properly utilize that much power. Even on the track there are very few times I tell myself "I wish I had more power". Usually I am wanting a bit more grip or more brakes as the power seems fine 95% of the time with the Dinan power mods I have already done.
Those that follow BMW rumors know about the M2 Competition (M2 CS) coming out. I have already been asked why I based this build on the original M2 and not wait for the M2 CS? There are a few reasons. The first is that when I bought this M2 and thought about the build the M2 CS was only a whisper. The second is that the M2 CS will have a new engine (a detuned version of the S55 from the M3/4) yet the M2 CS will cost an estimated $10k more. For $10k I could always tune up my M2's power to match or surpass the M2 CS's power if I really wanted to. If I was to do that I would certainly go with Dinan's P2 Power Package. But the biggest reason I did this build on the original M2 is that I am not sure I need more power given this is a track oriented car versus a street or drag car. I want the best stopping power possible so I can dive into turns and I want power I can confidently lay down coming out of turns. For that I don't need the M2 CS but rather I need big brakes, great suspension, and a balanced setup. And from what I have heard, the M2 CS will not upgrade the brakes or suspension over the original M2 as the M2 CS upgrades are focused on the engine and cosmetics. And even if they did upgrade the brakes they still would not match the Sparta Evolution brakes I am about to put on. So I have decided not to fall into the age old trap of simply wanting more power. I am focused mostly on getting power I can lay down and having a great suspension that compliments the balanced M2 chassis. Plus I happen to have an M2 laying around :)