Hi, sorry if this has been done before, but my searches couldn't find much info about performance gains per exhaust manufacturer/configuration. I can find tons of info/videos for the sound each one makes, but next to nothing about actual HP numbers.

So, if it's not too much trouble, could people chime in with documented or measured HP increases for any exhaust system they are aware of?

Keep the list to cat-back, DP, or turbo-back systems (not just mufflers) that do not require ECU program. Second cat delete allowed. I've started a list of system I'm aware of. Please add any not already listed.

I'll start. The only numbers I've seen are...

NM Cat-Back = 12-15HP (crank or WHP not specified) Source: NM Engineering
Milltek SSXM402 = 10-12% HP increase (crank or WHP not specified) Source: M7 Speed
Borla =
Magnaflow =
VIP DP Series =
VIP AB Series =
Megan =
Scorpion =
Quicksilver =

 

I work on a lot of N14 and N18 Minis and HP gains from any of the manufactures is maybe 1-4 HP. All power gains will be from doing a catless downpipe and removing the second cat. I tell all my customers, if they want an exhaust, they should purchase one for the sound, looks and weight savings, but to not expect HP gains. I use my catless downpipe and a Magnaflow exhaust on my JCW Countryman and love the deeper burble sounds. My HP gains come from the ECU tune, downpipe, and bigger turbo. mQubed Motorsport, Manic Tuning Dealer

 

Ah, I suppose that explains why there isn't much info on it. How does NM claim those numbers, then? Also, I wonder where M7 is getting those numbers for the Milltek exhaust?

 

They are all getting numbers because they are removing the second cat. You can weld a straight piece of pipe for $50 and get the same bump in HP from your stock exhaust. If you are looking at power adders, look at tuning, downpipe and intercooler

mQubed Motorsport, Manic Tuning Dealer

 

Ok, cool! Thanks for the info!

 

Mario sorry just need some clarification. I am at an impass here. I have a catless downpipe on the way and im looking at exhausts that remove the secondary cat only because of the restiction and the requirements for Manic stage 2 (but honestly would rather keep the stock and exhaust and stay relatively quite). Are you saying i would still have a pretty good increase and remain somewhat under the radar sound wise if I was to keep the stock exhaust from the downpipe back (keeping secondary cat and resonator) and lets say order a FMIC and get a Manic tune (i already have an air intake). Would that be considered stage 2?

 

That would be stage 2, you can remove the second cat with a small piece of straight pipe and it will get you maybe 10hp at the top of the RPM range. You could also leave the second cat in. Many of my customers run stock exhaust on a stage 2. I ran a stock exhaust on my GP with stage 4 and JCW Countryman with Stage 3.
Make sure you change the plugs to a colder plugs and tighter gapping

mQubed Motorsport, Manic Tuning Dealer

 

Personally i have the Scorpion exhaust for my mini countryman s all4 and love the sound so much! its much deeper and gives some louder pops. I felt a slight power gain but not much. I vote for the scorpion cause its a direct fit/no cutting. Gets rid of the second cat and resonator and bolts right to the downpipe.

 

Ended up finding a deal on the Milltek cat back. Installing this Friday. Shouldn't need any cutting, either.

 

I don't want to do catless downpipe. Emissions in VA are pretty strict.

 

You should be fine with emissions with any exhaust that is catless from the down pipe back. I live in upstate NY and have no probs with my downpipe back exhaust that is catless and has resonator deletes

 

Doesn't a catless DP delete the first cat, which is monitored by the O2 sensor? Anything that removes an O2 sensor will fail in VA.

 

...and even if it doesn't remove the O2 sensor, it will certainly cause a CEL, which is an automatic fail. They won't even run the inspection if there is a CEL.

 

Manic Stage 2 will remove the CEL. I have a Scangauge in my car and it always says I'm ready for inspection with no faults. I don't know how often you have emissions but mine is every 2 years for now. It takes roughly an hour to swap the DP. I'd surely swap it every 2 years for the benefits it gives if I had to.

 

Two years here, as well. Even when the CEL is removed, will their scanner show out of whack readings?

Certainly something to think about, though.

 

Mario, i have an akra 100 cell also, and full milltek cat back (i have both options - resonated or not resonated - now is not resonated)

Do you think this ressonator, which have direct and free pipe (the muffler is around) could hold pressure. How? Resonance?

I'm just asking becasue i was thinking to try a diferent set: completly free 70/63mm downpipe with mid resonator from milltek (don't like to much noise)

Thanks in advance!

 

You will gain a little bit of power going from 100 cell to a fully catless downpipe and sound will go up about 5%.
I would put the resonator back on the car if you want a quieter and deeper sounding exhaust.

mQubed Motorsport, Manic Tuning Dealer