Mach5 downpipe and SS exhaust review

[Milk242]

These days the car is living at the track, so the valve function isn’t a big issue. I might try the factory valve on the M5 exhaust, I do have a Milltel valve controller too, but never fitted it.

Was hoping this SS exhaust with insulation plus a decat would be the be all end all, but it’s not really. It’s too loud and I preferred the sound of my Aerie Ti exhaust plus Aerie sports cat. Probably should have stuck with it, added the Milltek and saved myself some money

Last time I ran with the Ti exhaust the exhaust valve was rattling after a session on track, but that wouldn’t have been an issue with Milltek. You really want the valve fully open on track, else it causes various issues.

I’m curious what the titanium sounds like. For me, my mach5 downpipe and exhaust sound sublime, especially in the upper rpm limits with valves fully open and the pops and crackles on downshifts puts a smile on my face every time I hear it.

 

[lynchy73]

I’m curious what the titanium sounds like. For me, my mach5 downpipe and exhaust sound sublime, especially in the upper rpm limits with valves fully open and the pops and crackles on downshifts puts a smile on my face every time I hear it.

I’m going to fit the Aerie Sports Cat with the M5 exhaust. I want to fit the factory ECU again and with the decat I’m gonna have CEL. Down the road I might fit the Aerie Ti exhaust again, in my memory it was quieter but had a nicer tone to it (had a cat though, so that’s gonna make a big difference).

Having some issues, not sure if it’s the stage 1 ECU or something else, so want to go back to factory ECU and see if the issue remains or not.

Basically I’ve been getting inconsistent power with the stage 1 ECU, but CEL are clear and no OBD errors. Sometimes I’m getting over stock power, really strong, then it will go weak, with maybe 300hp available. Not sure what’s going on, but I’m going back to factory and getting a milder tune on the tuned ECU (removing the pops/bang too, it’s a bit OTT on the tuned ECU).

The M5 exhaust with decat, valves open and pops/bang tune is a bit much IMO. Too loud and doesn’t have that quality sound it seemed to have before with the Ti plus sports cat. You can have too much of a good thing

 

[Milk242]

I’m going to fit the Aerie Sports Cat with the M5 exhaust. I want to fit the factory ECU again and with the decat I’m gonna have CEL. Down the road I might fit the Aerie Ti exhaust again, in my memory it was quieter but had a nicer tone to it (had a cat though, so that’s gonna make a big difference).

Having some issues, not sure if it’s the stage 1 ECU or something else, so want to go back to factory ECU and see if the issue remains or not.

Basically I’ve been getting inconsistent power with the stage 1 ECU, but CEL are clear and no OBD errors. Sometimes I’m getting over stock power, really strong, then it will go weak, with maybe 300hp available. Not sure what’s going on, but I’m going back to factory and getting a milder tune on the tuned ECU (removing the pops/bang too, it’s a bit OTT on the tuned ECU).

The M5 exhaust with decat, valves open and pops/bang tune is a bit much IMO. Too loud and doesn’t have that quality sound it seemed to have before with the Ti plus sports cat. You can have too much of a good thing

Oh wow forgot you are running a decatted downpipe, I bet that thing is loud .

Yea I decided to do a jb4 instead of ecu tune since there is no one local to me that can tune it even if I got the ecu unlocked.

Hopefully you can get your tune figured out so you can keep running the decatted downpipe.

 

[lynchy73]

Oh wow forgot you are running a decatted downpipe, I bet that thing is loud .

Yea I decided to do a jb4 instead of ecu tune since there is no one local to me that can tune it even if I got the ecu unlocked.

Hopefully you can get your tune figured out so you can keep running the decatted downpipe.

It’s too loud to be honest, curious to hear it with the cat fitted. Want to see how it drives with the factory ECU again, hopefully the issues with the power were the tune, not something more serious going on. It’s nice to have the cloned ECU, so I have the option to swap back.

TBH on the track that normally go to, the extra power isn’t that necessary. I suspect going too far with an ECU tune, without cracking the TCU ends up causing issues. Gonna try a new milder tune that stays within the TCU limits. It’s 1 thing to have a few pulls in the road, it’s another thing altogether to hammer the car on track.

 

[675430VME]

Just take Ryan's recommendation and put your stock ecu and exhaust back on so the valve problem can show up on the factory diagnose and get it fix or replaced. Ryan had fixed a few Emira with similar problems. Also, the shop who did the installation was really not that familiar with the Emira. The tune is fine honestly, and the extra power helps a great deal. Ryan's first rodeo on Nurburgring was 7:58 with old tires and stock ecu. His second attempt a month later with fresh tires and stage 1 tune was 7:39, that's a whooping 19 seconds advance with the same suspension setup. Ryan ran multiple laps on Nurburgring without getting power cut. TCU will indeed give warnings when you push for torque when the tranny is hot but that will only trash your transmission rather than getting power cut. Most of the power cut occurs when there is a valve problem.

 

[lynchy73]

Just take Ryan's recommendation and put your stock ecu and exhaust back on so the valve problem can show up on the factory diagnose and get it fix or replaced. Ryan had fixed a few Emira with similar problems. Also, the shop who did the installation was really not that familiar with the Emira. The tune is fine honestly, and the extra power helps a great deal. Ryan's first rodeo on Nurburgring was 7:58 with old tires and stock ecu. His second attempt a month later with fresh tires and stage 1 tune was 7:39, that's a whooping 19 seconds advance with the same suspension setup. Ryan ran multiple laps on Nurburgring without getting power cut. TCU will indeed give warnings when you push for torque when the tranny is hot but that will only trash your transmission rather than getting power cut. Most of the power cut occurs when there is a valve problem.

The exhaust valve on the Mach 5 Exhaust is mechanically fixed wide open and the factory valve is mounted on the Mach 5 plate, away from the Exhaust. There are no CEL, so far as the ECU knows the Factory valve is functioning normally.

 

[Kaz]

I am running the Aerie sports cat with the Mach5 race exhaust - it's awesome. So...it took a lot of starts but I got a slew of codes that I can't erase with my normal scanner that are the same valve related codes from earlier in this thread from the OP. I am still using the Milltek controller inline with the stock valve controller, that is attached on the relocated Mach5 mount in the upper left corner. My Mach5 part did not slot correctly with the stock motor so we decided to keep the Milltek connected in case the car wants to still see readings.

Does anyone know if the stock valve controller needs to see resistance in that motor, and that even with Milltek if it's just spinning in free air it will give all those error codes? What a pain lol. Hate to have my shop take the whole rear end apart again just for this. P1438 / P1439 / P13C2 <- and I can clear the active codes but once I restart the car they are triggered again so I have a permanent CEL, which is fine lol. Do any of these codes affect drivability or are they nuisance codes? Car seems fine...

 

[Milk242]

When I was running the relocation kit, after figuring out the blown fuse, it was running fine with no codes. I ran it always open. Switched back to stock valve and milltek so I could run OEM configuration when I wanted instead of only open or close that the mach5 valve controller kit does.

The only thing I noticed about the codes when they did show up was it affected the factory burble sounds, as in there were none now during downshifts but power seemed fine.

 

[Kaz]

When I was running the relocation kit, after figuring out the blown fuse, it was running fine with no codes. I ran it always open. Switched back to stock valve and milltek so I could run OEM configuration when I wanted instead of only open or close that the mach5 valve controller kit does.

The only thing I noticed about the codes when they did show up was it affected the factory burble sounds, as in there were none now during downshifts but power seemed fine.

Super helpful thank you! Where is the fusebox located behind driver left side? I guess worth checking right

 

[Milk242]

Super helpful thank you! Where is the fusebox located behind driver left side? I guess worth checking right

Yep fuse box behind driver side (USA). I think I posted a picture in this thread at some point

 

[lynchy73]

Super helpful thank you! Where is the fusebox located behind driver left side? I guess worth checking right

Yes, behind drivers side. @Milk242 listed the fuse earlier. You’ve most likely blown that fuse. It’s only 5A, it is very easy to blow when you connect the Mach5 controller (I found 7.5A was better). Once you blow the fuse, the factory valve will not function and you immediately get several codes. Once the fuse is replaced, the codes should clear.

 

[Kaz]

Yes, behind drivers side. @Milk242 listed the fuse earlier. You’ve most likely blown that fuse. It’s only 5A, it is very easy to blow when you connect the Mach5 controller (I found 7.5A was better). Once you blow the fuse, the factory valve will not function and you immediately get several codes. Once the fuse is replaced, the codes should clear.

getting back there now, the harness bar makes access back there a pain lol. I don't have the Mach5 controller, it's just the stock controller still connected to the Milltek and relocated in the bracket they give - I thought that would help any issues since it's just sending back to the car everything is fine. But yeah we're checking the fuse first before taking diffuser off and doing all that, fingers crossed!

Ok fuse #13 is blown, we don't know what triggered it, replacing with 7.5A - thank you guys! power of knowledge on a forum is not to be underestimated lol!

Update 2 fixed fuse, codes came back after a restart

 

[lynchy73]

I had loads of issues related to the Mach5 cables melting, it’s currently melted…. If you aren’t running the extra M5 controller, the regular 5A fuse should be enough.

To test the valve operation, you can start the car in service mode (no brake, long press on starter). In that mode the valves function as far as I know. You can then try opening/closing the valve and listen to confirm it’s reacting. Gonna be hard to hear it when the car is running on your setup. Also, there should be no need to run the miltek if you are just running the factory valve on the relocation bracket, with no valve on the exhaust.

 

[Kaz]

I had loads of issues related to the Mach5 cables melting, it’s currently melted…. If you aren’t running the extra M5 controller, the regular 5A fuse should be enough.

To test the valve operation, you can start the car in service mode (no brake, long press on starter). In that mode the valves function as far as I know. You can then try opening/closing the valve and listen to confirm it’s reacting. Gonna be hard to hear it when the car is running on your setup. Also, there should be no need to run the miltek if you are just running the factory valve on the relocation bracket, with no valve on the exhaust.

Again very good information thank you! The Mach5 relocation bracket has a notch where the stock valve controller fits into. On my bracket the notch would not line up with the stock controller no matter what, even turning the car on and trying different orientation and valve positions. So it would physically mount into the bracket. We decided to just tap out the little notch on the bracket so that the stock valve motor can just spin freely, and left the Milltek on so that the car would sense everything is fine. Which...I guess many parts of that plan didn't work lol. Does the stock valve controller motor "sense" resistance and need end points like how the bracket is designed? or could you in theory just mount the valve controller anywhere and have it spin freely? We'll take off the Milltek and plug in directly but will need a new M5 bracket the one they sent didn't fit the stock controller -

 

[Milk242]

Hmm that little spinner thing on their bracket should somewhat freely spin. You should be able to orient that bar in the orientation for your valve controller. Also if you unplug the valve while it was during cold start, I think it’s not in the factory idle position. I had that issue one time and when I plugged the valve motor back in not connected to the bracket or exhaust, it reoriented itself once it got power.

Its best to do all this work with the battery disconnected in case wires in the connector short something

Also from my experience, the codes don’t disappear right away, it took a few drive cycles for whatever reason even after I cleared it using my bt obd2 reader

 

[Kaz]

Hmm that little spinner thing on their bracket should somewhat freely spin. You should be able to orient that bar in the orientation for your valve controller. Also if you unplug the valve while it was during cold start, I think it’s not in the factory idle position. I had that issue one time and when I plugged the valve motor back in not connected to the bracket or exhaust, it reoriented itself once it got power.

Its best to do all this work with the battery disconnected in case wires in the connector short something

Also from my experience, the codes don’t disappear right away, it took a few drive cycles for whatever reason even after I cleared it using my bt obd2 reader

ah that's right, I will try some more drive cycles and just keep an eye on it...also just hoping when they finish my tune they can just zap all these codes out...lean, rich, exhaust valve, etc. one can dream lol

 

[lynchy73]

Again very good information thank you! The Mach5 relocation bracket has a notch where the stock valve controller fits into. On my bracket the notch would not line up with the stock controller no matter what, even turning the car on and trying different orientation and valve positions. So it would physically mount into the bracket. We decided to just tap out the little notch on the bracket so that the stock valve motor can just spin freely, and left the Milltek on so that the car would sense everything is fine. Which...I guess many parts of that plan didn't work lol. Does the stock valve controller motor "sense" resistance and need end points like how the bracket is designed? or could you in theory just mount the valve controller anywhere and have it spin freely? We'll take off the Milltek and plug in directly but will need a new M5 bracket the one they sent didn't fit the stock controller -

That doesn’t sound right on your relocation bracket. The factory valve motor is really critical regards the open and closed position. Whatever it’s mounted to, must have end stops that closely match the original calibration, or else the valve needs to be recalibrated on Lotus diagnostics. I don’t think it needs any mechanical resistance, it’s all about maintaining the end stop angles, from my understanding. I believe the Miltek can bypass that to some extent, but I’ve no experience with the Miltek.

Personally, the M5 bracket seemed to work just fine for me. My problems were pretty much cable/fuse related. So long as the factory valve was connected and powered, I wasn’t getting any errors. Any errors I got, due to blown fuses or whatever, would clear once I fixed the issue and cleared the codes with a basic OBD tool.

I guess there is something wrong with your bracket, or maybe it was assembled wrong. It definitely should have circa 90 degrees range of motion between the end stops, if it’s not like that, it’s gonna generate errors. If the valve motor was run without any end stops, it might mess up the calibration and you might need to get it recalibrated.

 

[docron]

Thats what @Kaz and I were discussing, that the valve controller probably test calibrates the valve on start up and if there is no resistance, it think the valve is nonfunctional/broken and throws the codes.

My Mach5 valve relocation kit “notch bar” was in this orientation and my valve controller just fitted right on without issues and i havent blown fuse 13 or thrown any codes for valve actuator malfunction.

 

[lynchy73]

Thats what @Kaz and I were discussing, that the valve controller probably test calibrates the valve on start up and if there is no resistance, it think the valve is nonfunctional/broken and throws the codes.

My Mach5 valve relocation kit “notch bar” was in this orientation and my valve controller just fitted right on without issues and i havent blown fuse 13 or thrown any codes for valve actuator malfunction.

View attachment 79786

I very much doubt any sort of valve misalignment could cause the fuse to blow. The motor is designed to bang into stops, it’s not gonna blow anything from rotating and hitting into stops, even if those stops aren’t where they should be.

My guess is that a cable or the Miltek box was burnt or damaged somehow, that caused a short and that blew the fuse. I’ve had loads of issues with blown fuses/burnt cables. Things get really hot back there.

 

[bmwzimmer]

Sounds like way too much trouble or potential trouble for a set and forget type of owner like me that just wants a bit more sound. Who makes a good sounding GPF back exhaust that does the trick without any risk of throwing codes or touching any of the emissions sensors?