[Youno]

Hey I'm new to the forums and I tried a search and couldn't find any such answers (although I'm sure they're on here somewhere).

When do the turbos on my e90 335i start boosting and when do they reach max boost? Also, if I were to mess with the wastegate some would I be able to get a bit more boost?

Thanks!

[enrita]

Originally Posted by Youno

Hey I'm new to the forums and I tried a search and couldn't find any such answers (although I'm sure they're on here somewhere).

When do the turbos on my e90 335i start boosting and when do they reach max boost? Also, if I were to mess with the wastegate some would I be able to get a bit more boost?

Thanks!

Just get a tune..... You cant mess with wgs.
They spool fast and hit stock max 8 psi.

[E90SoFlo]

Originally Posted by enrita

Just get a tune..... You cant mess with wgs.
They spool fast and hit stock max 8 psi.

posting machine going on!!

Yes 2k rpm and they are building, and max boost is 8psi.

[Youno]

Originally Posted by E90SoFlo

posting machine going on!!

Yes 2k rpm and they are building, and max boost is 8psi.

ah that's what I was wondering. So they start boosting 2k and just keep increasing their boost to about 4psi each all the way up till redline?

[enrita]

no they hit almost instantly 8 psi and taper to 6 or something.

[E90SoFlo]

Yeah 3500-5000rpms 8psi +/- tapering to 6psi at 7000k rpms

[Yodaime]

BOOST!

[Streetluger06]

The turbos are both running 8psi at half of the airflow needed by the engine. 4psi + 4psi does not = 8psi total for the situation. But 8+8=8.

[mundo74]

At high idle. Just removed my intercooler today to change the waterpump. Started the car w/o the intercooler and was surprised to hear a whoosh from the turbo discharge pipe. It was actually pushing off my hand at the cold start idle!

[Bakeme521]

I think if you take an 8mm wrench you can adjust the wastegate manually to run more boost

[eamon]

I didn't know wastegates had so much to do with boost.

Just curious then, if I have a muffler delete, there is less back pressure in the system meaning less pressure on the wastegates.

Will that effect performance or reliability in any way?

[eamon]

I didn't know wastegates had so much to do with boost.

Just curious then, if I have a muffler delete, there is less back pressure in the system meaning less pressure on the wastegates.

Will that effect performance or reliability in any way?

[boostaholic786]

Having a muffler delete just really has to do with the way the car sounds. The stock muffler is actually not that restrictive to be honest. What is restrictive is the secondary cats, not so much the muffler. What most people run is Catless DP's secondary cat delete and keep the stock muffler just for sound sake. With the secondary cats off you get more power, better exhaust tone/note, and its WAY less restrictive. If you like your muffler delete then cut the secondary's as well and throw on some vibrant resonators to tone it down. Its way to loud for me with just straight pipes no muffler. just my 2cents

[eamon]

Originally Posted by boostaholic786

Having a muffler delete just really has to do with the way the car sounds. The stock muffler is actually not that restrictive to be honest. What is restrictive is the secondary cats, not so much the muffler. What most people run is Catless DP's secondary cat delete and keep the stock muffler just for sound sake. With the secondary cats off you get more power, better exhaust tone/note, and its WAY less restrictive. If you like your muffler delete then cut the secondary's as well and throw on some vibrant resonators to tone it down. Its way to loud for me with just straight pipes no muffler. just my 2cents

Are there any negatives to a less restrictive downpipes? I only have a tune. Would a downpipe + tune setup be ideal or should I go for other mods first?

[rader1]

Originally Posted by eamon

I didn't know wastegates had so much to do with boost.

Just curious then, if I have a muffler delete, there is less back pressure in the system meaning less pressure on the wastegates.

Will that effect performance or reliability in any way?

The wastegates are what controlls/regulates boost. The wastegates default to open when no vaccuum is applied. When requested load increases the DME sends the command to apply vaccuum to the wastegate actuators increasing the WGDC(amount of time the wastegate is closed compared to open) which in turn builds boost. In a nutshell.

Originally Posted by eamon

Are there any negatives to a less restrictive downpipes? I only have a tune. Would a downpipe + tune setup be ideal or should I go for other mods first?

There are a couple possible down sides to downpipes, if youre in a state/area that does emmissions testing and you get catless DPs then you will need a DP fix to pass the test if it is a OBD2 readiness test but if it is a sniffer test then you'll need to put the stockers back in. You'll also get a CEL for cat ineffeciency unless your tune disables that. Also, the sound of WG rattle will get louder with aftermarket DPs.

With that said, DPs are a great mod and really brings the exhaust note to life and makes the car much more responsive. They also provide a nice boost in power when combined with a tune to take advantage of them.

[idrift4wd]

take off the engine cowl/micro filter and you can hear it spool! my car is tuned so it spools rather instantly.

[benzy89]

Originally Posted by eamon

Are there any negatives to a less restrictive downpipes? I only have a tune. Would a downpipe + tune setup be ideal or should I go for other mods first?

ONLY positives to buying less restrictive DPs. Getting DPs will allow you to run higher boost (less stress on the turbos, spool faster) and will free up 20 WHP/25 WTQ alone. If you're gonna buy DPs, look into an FMIC (and if it's financially feasible) get them both at the same time.

You'll be FBO, be able run 16-18 PSI and have you around 370 WHP/400 WTQ.

*I just took off my VRSF DPs off my car, they were used for only a month & FS if you're interested

[Youno]

Originally Posted by rader1

The wastegates are what controlls/regulates boost. The wastegates default to open when no vaccuum is applied. When requested load increases the DME sends the command to apply vaccuum to the wastegate actuators increasing the WGDC(amount of time the wastegate is closed compared to open) which in turn builds boost. In a nutshell.

There are a couple possible down sides to downpipes, if youre in a state/area that does emmissions testing and you get catless DPs then you will need a DP fix to pass the test if it is a OBD2 readiness test but if it is a sniffer test then you'll need to put the stockers back in. You'll also get a CEL for cat ineffeciency unless your tune disables that. Also, the sound of WG rattle will get louder with aftermarket DPs.

With that said, DPs are a great mod and really brings the exhaust note to life and makes the car much more responsive. They also provide a nice boost in power when combined with a tune to take advantage of them.

Ah it's these kinds of things that makes me hate living in California, the greenie tree-hugging capital of America. Is there any way for me to alleviate back pressure in the exhaust anywhere while still being able to pass the emissions test?

And yeah that's why I posted my OP, because I've heard of some people having the waste gate closed manually a bit and getting 12-15 psi. I know the oil will run hotter but so far even shifting high on the freeways I'm rarely ever over halfway on the temp gauge. I was curious also because I know the waste gate on the 335i is open by default compared to most other cars where the gate is default closed. Is it true the waste gate is only a wrench tightening away from more boost?

[enrita]

No you need a tune....

[rader1]

Originally Posted by Youno

Ah it's these kinds of things that makes me hate living in California, the greenie tree-hugging capital of America. Is there any way for me to alleviate back pressure in the exhaust anywhere while still being able to pass the emissions test?

And yeah that's why I posted my OP, because I've heard of some people having the waste gate closed manually a bit and getting 12-15 psi. I know the oil will run hotter but so far even shifting high on the freeways I'm rarely ever over halfway on the temp gauge. I was curious also because I know the waste gate on the 335i is open by default compared to most other cars where the gate is default closed. Is it true the waste gate is only a wrench tightening away from more boost?

There are catted DPs available(AR design, CP-e, Akrapovic and a couple others) however these on occasion have been known to fail and still fail emissions and if your inspector is VERY picky he may still fail you on a visual. However, another option is the stock 1M DPs. They are freer flowing than normal N54 DPs and are 100% emissions complaint. No catted DP is cheap so that sucks.

Some people have had sticky waste gate issues but that happens even 100% stock so that's just a luck of the draw.

IN NO WAY SHAPE OR FORM is tightening the waste gates a viable means of controlling boost. Either the DME will see over boost and slam the throttle plate shut(this is almost 100% what will happen) or worse. Not to mention the difficulty, if not impossibility, in adjusting both waste gates the same/accurately.

Almost every tune has some form of user adjustments and that's the proper way of setting boost

[Youno]

Originally Posted by rader1

There are catted DPs available(AR design, CP-e, Akrapovic and a couple others) however these on occasion have been known to fail and still fail emissions and if your inspector is VERY picky he may still fail you on a visual. However, another option is the stock 1M DPs. They are freer flowing than normal N54 DPs and are 100% emissions complaint. No catted DP is cheap so that sucks.

Some people have had sticky waste gate issues but that happens even 100% stock so that's just a luck of the draw.

IN NO WAY SHAPE OR FORM is tightening the waste gates a viable means of controlling boost. Either the DME will see over boost and slam the throttle plate shut(this is almost 100% what will happen) or worse. Not to mention the difficulty, if not impossibility, in adjusting both waste gates the same/accurately.

Almost every tune has some form of user adjustments and that's the proper way of setting boost

thanks! I'll look into the catted DPs.