Open ITBs "Velocity Stack " and the PCV system

[liam821]

liam821 Thankyou for the help! I'm in the middle of manual swapping my M3 so I'd like to do the velocity stack conversion while everything is already apart. So just to make sure I'm understanding correctly, I could install the velocity stacks and run in Alpha-N with external IAT without damaging the car? Just to get it up and running in the meantime before I get a tune in the near future.

I would literally only drive it from where you did the work straight to your tuner. I wouldn't drive around on Alpha-N without tuning, since the whole point of alpha-n is to use a set fuel table in the DME - it has no way of measuring airflow.

Personally, I'd never do it and would stick to using a MAP sensor with a MSS54HP ecu.

[MHoffmannM3]

Depends on a few things. You need to do something if you're going to change to a "CSL" style or open "velocity stack" style intake. The change is required because you're removing the MAF from the intake. The IAT is part of the MAF, so if you're removing the MAF you need to do something so the car knows the air temperature.

You have three options to keep the stock DME:

a) Keep the MAF and use an intake that is compatible (so no CSL intake or ITB velocity stacks)
b) Run the DME in alpha-n with a IAT. Alpha-n uses a set fueling table based on throttle position and N for RPM. It's basically like a tuned "safe-mode" without the check engine light. This just requires an IAT.
c) Run the DME in map mode (like an e46m3 csl). This uses a MAP sensor, throttle position, and IAT to calibrate fuel requirements. This requires an MSS54HP ecu, map sensor, and IAT.

So is tuning required? Meh depends. But I would lean toward yes if you go to a CSL-style intake or velocity stacks.

liam821 Thankyou for the help! I'm in the middle of manual swapping my M3 so I'd like to do the velocity stack conversion while everything is already apart. So just to make sure I'm understanding correctly, I could install the velocity stacks and run in Alpha-N with external IAT without damaging the car? Just to get it up and running in the meantime before I get a tune in the near future.

[liam821]

liam821 Hello. New to this forum and just had a question on the CSL conversion as I'd like to do this to my M3. Is tuning required as well or is an external IAT relocation all that is required?

Depends on a few things. You need to do something if you're going to change to a "CSL" style or open "velocity stack" style intake. The change is required because you're removing the MAF from the intake. The IAT is part of the MAF, so if you're removing the MAF you need to do something so the car knows the air temperature.

You have three options to keep the stock DME:

a) Keep the MAF and use an intake that is compatible (so no CSL intake or ITB velocity stacks)
b) Run the DME in alpha-n with a IAT. Alpha-n uses a set fueling table based on throttle position and N for RPM. It's basically like a tuned "safe-mode" without the check engine light. This just requires an IAT.
c) Run the DME in map mode (like an e46m3 csl). This uses a MAP sensor, throttle position, and IAT to calibrate fuel requirements. This requires an MSS54HP ecu, map sensor, and IAT.

So is tuning required? Meh depends. But I would lean toward yes if you go to a CSL-style intake or velocity stacks.

[MHoffmannM3]

liam821 Hello. New to this forum and just had a question on the CSL conversion as I'd like to do this to my M3. Is tuning required as well or is an external IAT relocation all that is required?

[liam821]

1) You can use my trumpet clamp design if you'd like, it's made for pre 10/2004 style trumpets. Basically, unscrew the endcap off the trumpets and either cut or push them out. My clamp uses the pre 10/2004 style throttle body boots BMW part number 11612466477. I reused all the factory clamps as well. You'll want to print it in ABS or PETG as it has better heat resistance, I used PETG. You'll need to print them with supports. There is a flat part of the clamp in the middle, that side you'll want to print facing down towards the build plate. You can grab the STL and print/modify it yourself off my website here: https://liam821.com/liam821-e46-m3-trumpet-clamp.stl

I should add...It takes about 37 hours to print three clamps. If anybody is interested and don't have access to a 3d printer, hit me up, for a small fee I can print a set and mail them.

[liam821]

Looks great, Iove to see people designing (and printing) their own ideas! Curious what kind of filament you printed with?

I printed it in PETG which has a better heat tolerance than PLA. ABS would even be better to use but printing it stinks up my office. I've put maybe 100 miles on it and they seem to hold up just fine, they get warm to the touch but never so hot you burn yourself. There is cool air (hopefully) going through and nothing is touching the cyl head directly.

This looks so sweet. I really wonder how it'll do in the longer term - please continue to post as time goes on to show the progress? Perhaps this could be a beta for a kit that you could potentially provide for the community if enough people have interest. Any sound clip / video would be awesome as well 😃

Sure, I'll keep you posted. I have a few sound clips here. I have a stock exhaust so the car is basically stock quiet until over 3000rpms and than you

Windows up, my daughter filming - it's a bit definitely louder in real life, especially with the windows down. https://www.youtube.com/watch?v=vHg_Iby-Ezk

If anybody else wants to try, the shopping list is pretty simple. This is really the same as the PSDesign kit - they use factory ITBs too although they say otherwise...

1) You can use my trumpet clamp design if you'd like, it's made for pre 10/2004 style trumpets. Basically, unscrew the endcap off the trumpets and either cut or push them out. My clamp uses the pre 10/2004 style throttle body boots BMW part number 11612466477. I reused all the factory clamps as well. You'll want to print it in ABS or PETG as it has better heat resistance, I used PETG. You'll need to print them with supports. There is a flat part of the clamp in the middle, that side you'll want to print facing down towards the build plate. You can grab the STL and print/modify it yourself off my website here: https://liam821.com/liam821-e46-m3-trumpet-clamp.stl

2) pull your stock trumpets out of an airbox - I bought a spare online for $40. The pre 10/2004 are where it's at.

3) Get some filters, while rolling without might look cool sucking in small children and breaking your engine isn't. I used ITG JCS-11 filters, you can get them here https://itgfilters.net/products/itg-...iant=787101643

4) You'll need to run alpha-n or do a CSL conversion as I did, so external IAT sensor and/or CSL MAP sensor depending on if you're alpha-n or not.

5) You'll probably want to make a plate that goes under the trumpets and helps direct air. This is the template I used from somebody over on m3cutters - thank you - I used a thin piece of aluminum I bought at Home Depot. You can wrap it with vinyl or spray paint it.



You'll probably want to do some air ducting to duct cold air towards the trumpets.

6) PCV system. You'll need to route your valve cover vent hose into a catch can, and then do something with it. I used the stock airbox oil drain on my catch can so I would never have to empty mine. I also routed the brake booster air shutoff valve into the same place. You don't want to vent into the engine bay, especially close to the air cabin intake, it stinks, ask me how I know.

That's literally it. Cost me about $175 all in including the CSL conversion pieces, the most expensive part was the ITG filters. I could have probably found a cheaper filter, but let's face it, the ITG filters look sick.

Here are a few more pictures:

You can see the trumpets are held in place using the factory pin (right trumpet, just under my index finger to the right)




You can use a CSL style oil dipstick or bend the stock one to move it out of the way. I'm not sure what I want to do yet so I left it as-is.

[Mystic3]

Great to see American ingenuity at work.
well done !!

[Icecream]

that's pretty cool. What printer and filament did you use?

[ChapterM3]

This looks so sweet. I really wonder how it'll do in the longer term - please continue to post as time goes on to show the progress? Perhaps this could be a beta for a kit that you could potentially provide for the community if enough people have interest. Any sound clip / video would be awesome as well 😃

[Albino09]

Probably my best option is to use a CSL style airbox...so that's why BMW made that eh.

The thing is, a CSL airbox is the optimized version of running open stacks in a modern car. Old machines didn't have to worry about consuming the fuel vapor venting from the tank, they just vented it to atmosphere. The only thing you are gaining by running open stacks is additional noise and a subjective aesthetic change. I do happen to think it looks cool though.

[Cubieman]

Very cool.

[oceansize]

Love to see experimentation even if it is for no one other than yourself.

[Will ZCPM3]

This is awesome. Interested to see how those parts hold up.

[TwoD]

Looks great, Iove to see people designing (and printing) their own ideas! Curious what kind of filament you printed with?

[digger]

Route the vent away into wheel arch or down under the car behind head light