Mach5 downpipe and SS exhaust review

[Milk242]

Finally got the Mach5 downpipe and stainless steel exhaust installed, plus their valve controller.

Overall, super happy with it. The sound is awesome—nice deep rumble. In Sport or Track, you get some drone in the lower gears on the highway, but once you’re in the higher gears it goes away. Inside, it kind of sounds like the fake i4 noise, except this time it’s actually real since I unplugged the wire. No clue what it sounds like outside other than idle and a few revs in the driveway.

As for CELs: none caused by the downpipe. I did cause one myself when installing the valve controller because I plugged the wires in wrong (they come without connectors so you can route them through the trunk). That ended up blowing the exhaust valve fuse in the fuse box behind the left seat, which took way too long to track down. Replaced the fuse, wired everything correctly, did a couple start cycles, and the CEL went away.

Only extra thing I added was a silicone-coated fiberglass heat sleeve for the valve controller wires (basically like the OEM shielding) because my wire routing felt a little too close to the exhaust.

All in all, the exhaust sounds great, no downpipe related CELs, and the valve controller moves the OEM unit away from the exhaust so you’re less likely to end up in limp mode if the OEM controller ever melts.

Edit:
Forgot to mention that the crackles is now really pronounced in sport and track mode when coming to a stop rapidly and the car is downshifting through the gears

 

[finny76]

How much does this setup run? any videos?

 

[Milk242]

How much does this setup run? any videos?

While I was living in Taiwan, I bought the downpipe for 27,800 NTD so roughly about 900 usd. While back in the US, I ordered their exhaust and valve controller and that was 50,410 NTD so roughly 1620 usd.

I’ll try to get some recorded videos

If anyone is in the DFW area, I’ll freely give a demonstration.

Edit:
Keep in mind the downpipe price I got was most likely because I was in Taiwan and ordering directly from their company which is also in Taiwan.

 

[Kaz]

That's awesome! if you can keep eye on pending codes, mine with my Aerie downpipe took a while to show up, about 10 drive cycles before it showed up in pending, then active, then permanent. Hopefully yours stays clear and super awesome for US cars if it stays clean and have no plans of modding the ECU to get rid of codes permanently. and yeah can't wait to hear the exhaust!

 

[Milk242]

Yea I’ve been keeping an eye on pending codes, so far I only see the valve controller related codes. I drove the car all day yesterday and CEL was on due to those codes and started it up this morning and no more CEL.

These were the codes I was seeing
U0141
U0168
P13c2
P246b
P1439

 

[lynchy73]

I recently had a Mach5 Exhaust fitted, along with their valve controller, but I’ve fitted a decat. It’s pretty loud and I was coming from a Ti V1 Aerie Exhaust with Aerie Sports Cat.

Where did you locate the factory valve motor? Mine was fitted up under the heat shielding, in front of the rear plate.

 

[Milk242]

I recently had a Mach5 Exhaust fitted, along with their valve controller, but I’ve fitted a decat. It’s pretty loud and I was coming from a Ti V1 Aerie Exhaust with Aerie Sports Cat.

Where did you locate the factory valve motor? Mine was fitted up under the heat shielding, in front of the rear plate.

They provided a mount for the OEM valve controller and it screws into the 2 screw holes right next to where the sway bar mounts

 

[lynchy73]

They provided a mount for the OEM valve controller and it screws into the 2 screw holes right next to where the sway bar mounts

Thanks for confirming. I suspect mine hasn’t been wired in properly, I think they have connected the OEM cable directly to the factory valve motor, not using the mach5 cable. The Mach5 control unit is going to the Mach 5 controller, the valve controller is working. I managed to get Mach5 to supply the missing pipe between the main exhaust and the downpipe and that is now fitted.

They also swapped my stage 1 ECU for the factory ECU so now have CEL with the decat gonna be a bit of a hassle now to get that cleared. I shouldn’t have left the factory ECU in with the parts

Charge cooler upgrade is done, the red coolers look nice from the front of the car. Also got the suspension done, so now have -3deg or a little more, it is very obvious from the stance, really pushed in the top of the wheels. Not sure if I’ll run more offset to push the wheels out further, or if that will mess up the geometry.

 

[Milk242]

Hm, the Mach 5 cable has 3 connectors, one to the factory valve controller, one to the OEM valve input cable and one to the Mach 5 controller box that sits in the trunk. Then from the controller box another cable that goes to the Mach 5 supplied valve controller. I’ve attached the installation manual.

Yea I still also have the charge cooler to install, not sure if I want to upgrade the oil and transmission coolers up front. And I’m thinking about sending in my ECU to autotuner to get it unlocked since they are only charging 250 euros and then I can either tune the ecu directly using an off the shelf tune for the m139 engine or clone it to an other m139 ecu and also do an off the shelf tune.

 

[lynchy73]

Hm, the Mach 5 cable has 3 connectors, one to the factory valve controller, one to the OEM valve input cable and one to the Mach 5 controller box that sits in the trunk. Then from the controller box another cable that goes to the Mach 5 supplied valve controller. I’ve attached the installation manual.

Yea I still also have the charge cooler to install, not sure if I want to upgrade the oil and transmission coolers up front. And I’m thinking about sending in my ECU to autotuner to get it unlocked since they are only charging 250 euros and then I can either tune the ecu directly using an off the shelf tune for the m139 engine or clone it to an other m139 ecu and also do an off the shelf tune.

You mentioned having some issues with the valve controller cabling. What happened there? I see it should be plug and play, so a bit curious where it went wrong.

The guys that did the installation butchered the cable, that should join the factory valve to M5 box, and instead connected the M5 box to a 12V supply only, so M5 box can’t see the factory valves status. Factory valve was connected to factory cable, on the M5 plate, so at least the ECU is seeing the valve.

 

[Milk242]

You mentioned having some issues with the valve controller cabling. What happened there? I see it should be plug and play, so a bit curious where it went wrong.

The guys that did the installation butchered the cable, that should join the factory valve to M5 box, and instead connected the M5 box to a 12V supply only, so M5 box can’t see the factory valves status. Factory valve was connected to factory cable, on the M5 plate, so at least the ECU is seeing the valve.

The plugs that connect to the Mach 5 box comes depinned for routing purposes, I accidentally flipped the wires when plugging them in and blew the 5 amp fuse in the fuse box for the exhaust valve actuator. I kept thinking maybe the box was busted or I needed my valve controller recalibrated by lotus but turned out it was the fuse.

So are you saying you are running an exhaust with no working valve controller on it? Is your exhaust valve just constantly closed?

 

[Lots_Of_Trouble]

Thanks for confirming. I suspect mine hasn’t been wired in properly, I think they have connected the OEM cable directly to the factory valve motor, not using the mach5 cable. The Mach5 control unit is going to the Mach 5 controller, the valve controller is working. I managed to get Mach5 to supply the missing pipe between the main exhaust and the downpipe and that is now fitted.

They also swapped my stage 1 ECU for the factory ECU so now have CEL with the decat gonna be a bit of a hassle now to get that cleared. I shouldn’t have left the factory ECU in with the parts

Charge cooler upgrade is done, the red coolers look nice from the front of the car. Also got the suspension done, so now have -3deg or a little more, it is very obvious from the stance, really pushed in the top of the wheels. Not sure if I’ll run more offset to push the wheels out further, or if that will mess up the geometry.

Got a pick of the charge cooler upgrade???