[Spoolsport]

Hi guys

I've uploaded my logs in the approval thread but thought I would make a seperate thread.

I'm having a strange issue that has me stumped.

I have 2007 335i N54.

Mods -

Catless downpipes
New turbo's
Charge pipe
Upgraded coils
New vanos solenoids
New boost solenoids
MHD E30
stage 2 plus ( I've also flashed it back to stock and still has similar issues)

The issue I'm having. Part throttle I will get a shuffle rattle sound from the wastegate and past 3krpm my exhaust note will sound extremely hollow and strange. Not to mention the car feeling flat and fatigued.

If Im coming out of a hard left or right hand corner my exhaust note will sound like a lancer with a bad exhaust leak. This also reflects how the car performs.

I'm getting a strong fuel smell from the exhaust. And the car doesn't accelerate as it should.

I'll upload my logs again. If I can finally get my car sorted I'll be able to finally sleep at night 🤦*♂️

https://datazap.me/u/boosty/running-...og=0&data=3-21

[SixSix]

I had the same issue when I installed downpipes, got a lot worse too when I tried out the MHD Wastegate Rattle fix option. This is the exhaust note of the wastegates being open on accel. If you pull the lines off your vacuum canisters and take it for a short drive you'll hear the exact same exhaust tone. Sometimes the DME just decides to open the wastegates up and leave them open periodically.

When I still had twins I found that usually in cooler weather, minimal load and uphill would cause the DME to open the wastegates up. Obviously with the wastegates open you're not making any boost, hence the sluggish feel.

I also found on the twins that anything below 1700 RPM would make the same noise if I accelerated moderately.

Unfortunately I didn't find a fix for this issue, just lived with it until I went single turbo. Didn't have any issues stem from the wastegate open condition, just was a very obnoxious and terrible exhaust note in my opinion.

If you take a look at your datalog and look at WGDC after PID you'll see the spikes up to 80%, the higher the percentage, the more open the wastegate is.

Now, your issue with the fuel smell out of the exhaust, check your turbo-downpipe v-band clamps, I've had the welds break on them before and smelled the leak.

Also, running an MHD tune will make your car run richer than usual, this is typically how OTS tunes are just to keep things safer for the engine.

[Spoolsport]

Originally Posted by SixSix

I had the same issue when I installed downpipes, got a lot worse too when I tried out the MHD Wastegate Rattle fix option. This is the exhaust note of the wastegates being open on accel. If you pull the lines off your vacuum canisters and take it for a short drive you'll hear the exact same exhaust tone. Sometimes the DME just decides to open the wastegates up and leave them open periodically.

When I still had twins I found that usually in cooler weather, minimal load and uphill would cause the DME to open the wastegates up. Obviously with the wastegates open you're not making any boost, hence the sluggish feel.

I also found on the twins that anything below 1700 RPM would make the same noise if I accelerated moderately.

Unfortunately I didn't find a fix for this issue, just lived with it until I went single turbo. Didn't have any issues stem from the wastegate open condition, just was a very obnoxious and terrible exhaust note in my opinion.

If you take a look at your datalog and look at WGDC after PID you'll see the spikes up to 80%, the higher the percentage, the more open the wastegate is.

Now, your issue with the fuel smell out of the exhaust, check your turbo-downpipe v-band clamps, I've had the welds break on them before and smelled the leak.

Also, running an MHD tune will make your car run richer than usual, this is typically how OTS tunes are just to keep things safer for the engine.

I just wanted to thank you for this amazing response! This is exactly what's

happened to my car. You described it to a tee!

I will investigate the downpipes next week!

Man, I've been scratchings my head for almost a damn year trying to diagnose this issue lol

[SixSix]

No worries, glad I could help someone out who had the same thoughts as myself.

I actually only realized this when I dropped my subframe to do engine mounts. Lowered the engine a little too much and the vacuum lines came off of the bottom of the vacuum canisters. Was able to figure it out immediately and pieced together the wastegate open exhaust note thing after taking it for a drive and having it sound super weird.

I would definitely inspect your vacuum lines if you are having the issue above 2000rpms.

[Spoolsport]

Originally Posted by SixSix

No worries, glad I could help someone out who had the same thoughts as myself.

I actually only realized this when I dropped my subframe to do engine mounts. Lowered the engine a little too much and the vacuum lines came off of the bottom of the vacuum canisters. Was able to figure it out immediately and pieced together the wastegate open exhaust note thing after taking it for a drive and having it sound super weird.

I would definitely inspect your vacuum lines if you are having the issue above 2000rpms.

Yeah mate I'm having this issue only soon as I hit 3000rpm. Below that I can just hear the wastegate flapper open and close.