[David@ActiveAutowerke]

Active Autowerke | F8X Exhaust System and Mid-Pipe Technical Overview

Many of you are familiar with the wonderful sound of our signature exhaust system, but we decided to create a thread to cover the technical specifications of our system and provide evidence that it performs just as good as it sounds!

All of our F8X systems are hand made here at our facility in Miami, Florida. The fitment on each unit is tested prior to shipping, and with in house quality control we can ensure that each system is manufactured to our standards.





Design

100% Stainless Steel Construction
Single pipe mid section for increased exhaust velocity and aggressive sound
Noise cancelling chamber to eliminate drone
Adjustable rear tips, available in stainless or matte black
Mounts using factory hangers
Rear muffler adjusts to fit with aftermarket diffusers

We chose the single pipe mid section design for two reasons:

By mixing the exhaust flow from both banks together we're able to promote increased exhaust velocity throughout the system. We found that the 3.5" single pipe maintains maximum exhaust gas speed without causing any restriction, allowing the turbos to spool quicker while also increasing flow and top end power.

Mixing both banks together also creates a very smooth sound. The S55 has a very unusual exhaust note and the dual pipe exhaust system that comes on the M3/4 does not help improve the tone at all. By combining the flow from each turbo together we were able to create a smooth, aggressive roar that sounds exactly how an M car should!

Here is a video of our mid-pipe compared to a stock system. We use pressurized air to demonstrate the effect of our design. You can see our design helps pull exhaust through the alternate bank.

Performance

Yesterday we strapped a bone stock M4 down on our Mustang dyno for some baseline runs. We then installed our signature mid pipe and rear exhaust system and ran the car on the dyno again. Below is the dyno sheet and raw data from before and after.

These runs represent numbers from the same car, on the same dyno, on the same day. No results have been altered or modified. Below the dyno is a raw data sheet of the dyno data. Both runs were performed in 4th gear.







Data Analysis

You will notice right away that around 3000rpm there is a huge difference in torque and horsepower. The happens because the fast, free flowing exhaust allow the turbos to spool quicker.

For the rest of the run our exhaust system continues to produce more torque and horsepower up to the rev limit.

The green highlighted data in the table represents peak numbers before and after. There are two yellow highlights for torque and horsepower, the first representing the maximum gain prior to the stock car achieving target boost, and the second representing the maximum gain after both runs have achieved target boost.

Maximum gain below 3800rpm: 80 Ft-Lbs and 42rwhp.
Maximum gain above 3800rpm: 20 Ft-Lbs and 17rwhp.
Peak gain: 12 Ft-lbs and 11rwhp.

We expect that gains will be amplified when used with higher boost levels. I will update the thread tomorrow with our results from today as we test our system with and without our Active-8 piggyback.

What does this mean?

Having the turbo spool sooner makes the vehicle easier to drive and will be quite noticeable on the street. The gains in the higher RPMs will be noticeable when driving aggressively or on the track.