I finally had the chance to go to dyno shop again to check what is the difference after installing Evolve Rear muffler and N55 mids sometime ago. I made close to 580 km. before doing this second dyno and the car is exactly same, nothing else changed since then. Did my best to secure close to identical conditions; same gas brand and type, same levels, same dyno shop and operator, same 4th gear runs ending around 6600 rpm, M button pressed, DSC off. I was not able to pick a day with exact same temperatures though but don't think the difference of max 5 degrees Celsius worth too much, was just a bit cooler today than the first dyno day.
Reminder: it is otherwise a stock car. Bone stock, peak power was 294.2 whp and peak torque was 339.9 lb.ft (note: car did better tq in another run with 342.9 lb.ft). Almost identical numbers with GIAC's Mustang dyno tested stock 1M, so reliable and believable.
It is a Mustang dyno reading seriously lower than some other dynoes. But it is well calibrated and consistent like its operator (great guy). Recently a 2012 stock E9X M3 dynoed there he told me, with 323 whp, before installing a supercharger and other stuff. I saw the chart and numbers which is confirming other Mustang dynoed M3s from US and other countries.
Today my 1M with stock down pipes, N55 mids and Evolve Race rear muffler dynoed 300.5 whp and 347.1 lb.ft.
So, registered an increase of 6.3 whp and 7.2 lb.ft wtq.
I am going to post the new chart and a second chart with old and new together as soon as possible, when I receive them by mail. The real good news is there is constantly more hp and torque after around 2600 rpm till the end, and the higher the rpm the higher the difference from stock car. The hp simply doesn't fall at all after 6000 even 6500 rpm and torque is also smoother at the top, lots of power and tq up there (stock was not too bad too compared to other N54s). The stock car's peak hp came at 5095 rpm while today it was reached at 5454 rpm.
This exhaust set up is just perfect for someone who wants a calm and refined sound before around 4000 rpm and wants the car sound mean and loud after that. And after this dyno I happily noticed that my butt dyno impressions during this last 580 kms. were right and revs flow easier now and when the sound starts getting really different vs. stock exhaust, which is after 4000, the car indeed is pushing harder all the way to the top.
If I follow the same suggestions for calculating the crank hp and tq, stock car was 350+ hp and 550+ nm and with the exhaust it is now 360+ hp and 560+ nm. The operator thinks it can be even more than 370 hp but I am playing safe and conservative here. Literally, only 23 less whp and around 60 % more wtq than a V8 M3, that's what it is, nothing more nothing less.
Another thing that I now know is there is no way you can make 15 whp or more just with a midpipe or rear exhaust on a bone stock car, you make less, even midpipes and muffler together hardly gets close to those numbers at crank. But whatever you make you can make at all the right places. I am sure a car with full bolt on mods and a good tune will have double or more gains from this exhaust set up but for me it just delivered everything I was hoping for
Charts and a new sound clip during one dyno run will follow.
"The mark of a great car is one whose overall competence exceeds what you should expect from its individual components and the 1M does just that", Chris Harris.
BMW 1M-SOLD-: TECH: Evolve Race+N55mids, Evolve IC, Michelin PSS, ER cp, aFe filter, CDVx, Vorshlag camber plates, BMS OCC EXTERIOR: trunk spoiler, blacklines, black grills, IND goodies INTERIOR: Alcantara steering wheel, steel pedals, custom mats, MPower e-brake.