Open ITBs "Velocity Stack " and the PCV system

[liam821]

I'm interested in the file or a printed set of three. Tried to PM you but, would not go through. liam821

You didn't read the thread very well... there is a link on the first page to the STL you can download and print yourself. If you need me to print you a set, PM me, and I'll print you a set.

[Mitchmarket]

I'm interested in the file or a printed set of three. Tried to PM you but, would not go through. liam821

[liam821]

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

I sold my M3 last year, so I put it back to stock. But I had put 15k miles on this (itb) setup, zero issues!

[liam821]

Hi there, I know that the post on your velocity stacks is old but I wondered if you recall what you did to block off the stock air induction system? I am going to cut a hole in the side of the piece to direct air to the stacks but I need to block off the air from escaping out the end. I think that there may be a 3d printed blank but I can't find it. Interested as to what you did if anything. Here is a link to a post with the example. https://www.e46fanatics.com/threads/...tacks.1098092/

Any help appreciated thanks Paul

I used a block-off plate (see post on the first page, half way down), which helped direct the air from the front and kept most of the road gross off the filters. I did not block off the air intake feed from the front bumper into the now gone factory airbox, I left that as-is since it helps direct cool air into the engine bay.

[SMC]

Hi there, I know that the post on your velocity stacks is old but I wondered if you recall what you did to block off the stock air induction system? I am going to cut a hole in the side of the piece to direct air to the stacks but I need to block off the air from escaping out the end. I think that there may be a 3d printed blank but I can't find it. Interested as to what you did if anything. Here is a link to a post with the example. https://www.e46fanatics.com/threads/...tacks.1098092/

Any help appreciated thanks Paul

[liam821]

liam821Im in the process of doing this but I cut the box in a way to act as a heat shield. Anyways, love your setup. Which ITG socks did you use? Which size? Thanks!

Cool, you should post a picture! I used ITG JCS-11 filters. You can buy them from pegasusautoracing.com or directly from ITG at itgfilters.net.

Any updates on this? Did you ever manage to do any dyno runs or mess with trumpet sizes?

No, I actually sold my M3 a few months back - *gasp* I know. I still have my ZHP, but that's Honda powered haha. My ITB setup I kept, however, it's in a box. I'm sure I'll get another e46m3 with s54 power at some point.

[9kracing]

Any updates on this? Did you ever manage to do any dyno runs or mess with trumpet sizes?

[Casa de Mesa]

...I cut the box in a way to act as a heat shield.

Can you post a pic of this? Would be interested to see what you came up with.

[tuxmonkey]

liam821Im in the process of doing this but I cut the box in a way to act as a heat shield. Anyways, love your setup. Which ITG socks did you use? Which size? Thanks!

[digger]

I'm convinced there's a ton of power to be made by changing the ITBs, but I don't feel like being the guinea pig... especially since I'm supercharged.

I'm not sure using factory trumpets will be the move unfortunately. As far as I can tell, the factory ITBs are 52mm... which is pretty small for a motor of this size. I'd like to see some big throttle bodies with a properly tuned trumpet.

https://honda-tech.com/forums/all-mo...sting-2841539/

People have tested bigger throttles and there doesn’t seem to be tons of gains, some builds could show some incremental gains.

The factory throttles are 50mm and unless you address the most restrictive part ie Inlet valve and ports you’re fixing in on the wrong area. 2x35mm valves are equivalent to 43mm with 88% throats

You could optimise trumpet length to bias induction wave tuning towards top end power at expense of some midrange but that’s for race only imo. The starting point is pretty good already it’s not a crappy m54/52 inlet system

with FI treat inlet as a engine equivalent to no boost I.e with 600whp at 1bar is 300whp NA so Inlet tuning is not massively different as boost is density not velocity

[liam821]

I've also printed a set of the adapter that yot've designed, although I put the ///M logo in the middle 😀
I know you used PETG for yours and I've used it for mine, but how did yours hold up in the long run?

ha! You're welcome. PETG has been holding up great. I have many thousands of miles on them now. PETG has a temperature rating of around 80C degrees, which is hotter than the intake manifold gets. ABS would be better but it's toxic to print and harder to print without warping and really only good for another 20c.

I've never tried nylon or some of the fancy carbon nylons they now have available. But those might even be a better material to use.

I'm convinced there's a ton of power to be made by changing the ITBs, but I don't feel like being the guinea pig... especially since I'm supercharged.

I'm not sure using factory trumpets will be the move unfortunately. As far as I can tell, the factory ITBs are 52mm... which is pretty small for a motor of this size. I'd like to see some big throttle bodies with a properly tuned trumpet.

https://honda-tech.com/forums/all-mo...sting-2841539/

Very interesting. I'd love to 3d model a bunch of different-sized trumpets and test back-to-back on the dyno. I'd imagine you're correct and a lot of power is to be found in tailoring the trumpet to the setup. Especially with larger cams that breathe more at high rpms. And yeah, we'd might need a larger throttle body setup. Does anybody have a set of Dinan ITBs lying around I could borrow? . Still might be interesting to see what different sized trumpets do to the powerband.

A good buddy of mine is getting a dyno (at least I hope!) and I'm sure he'd let me borrow it for a day. If it happens I'll be sure to make a post about it.

[9kracing]

I'm convinced there's a ton of power to be made by changing the ITBs, but I don't feel like being the guinea pig... especially since I'm supercharged.

I'm not sure using factory trumpets will be the move unfortunately. As far as I can tell, the factory ITBs are 52mm... which is pretty small for a motor of this size. I'd like to see some big throttle bodies with a properly tuned trumpet.

It goes to show you what happens when you use properly sized, well constructed, high quality ITB's. Most people think you can just throw a set of ITb's on a car and it'll make power. In this case, proper size and design is everything.

https://honda-tech.com/forums/all-motor-naturally-aspirated-44/profunction-kinsler-present-epic-all-motor-bseries-manifold-testing-2841539/

[liam821]

Hey liam821 , thank you for the comprehensive guide.
It's been very useful in my research in preparation for putting velocity stacks on my car.
May I ask how you cut out the trumpets from the airbox?
I can't find any info on that online

They're a pain to remove. For the earlier boxes pre 10/2004 with the yellow trumpets, I was able to unscrew the backing on each trumpet and then pound them with a mallet and they popped out. They're just glued in. If they don't want to come loose you'll have to use a sawzaw/cutting tool of some sort. Basically, just destroy the box while being careful not to mess up the trumpets.

[ivo2456]

Hey liam821 , thank you for the comprehensive guide.
It's been very useful in my research in preparation for putting velocity stacks on my car.
May I ask how you cut out the trumpets from the airbox?
I can't find any info on that online

[MHoffmannM3]

liam821 Sounds good. Thankyou very much for the help!