[thalastdon1985]

I've been reading here and there, along with studying pictures of M cars and it led me to want to fabricate an intake manifold similar to the s54 or even s50b32 euro air collector as it is called. After I searched for other posters that may have thought of this previously and did indeed find that one poster had the same idea around 2015, it encouraged me to persue it. Based on his continued posting on this forum, I have to assume he didn't pursue it. I went so far as to buy a used s54 air collector to study adapting it, but that obviously will not work unless I can find a way to run it with no alternator.

I now intend to have a custom air collector fabricated from aluminum and attach it to a set of 328i intake runners of a currently undetermined length. I believe the size of my plenum would need to equal the total volume of a 3 stage intake minus the runner volume I'll be attaching to. I was hoping from some input from other members here to get an idea of I am on the right track. I'm basically hoping for confirmation bias.

[desertman123]

Sounds like a fun project. Do you have any experience in CAD/CFD? Might be worth whipping up a mockup and seeing if there are benefits to be had. The stock setup is decently well optimized, but of course is still limited to numerous constraints set out by the accounting department (cost, ease of maintenance [dealership service], etc.).

Do keep in mind the valvetronic system allows for the intake manifold to have atmospheric pressure inside.

[thalastdon1985]

I don't have any experience with those programs. Nor do I have a great understanding of fluid dynamics in general. My view is that the stock manifold is optimized for better torque across the range. I should have mentioned that I'm looking for peak HP at 7400-7600rpm. I believe the intake manifold to be a key factor in making that peak power in lieu of a broader torque curve. I've been a motorcycle mechanic for most of my life and have been messing with N52 e90s for a few years now. I've seen plenty of superbike air boxes which are all itb. Ever single one is larger open plenum in to a velocity stack and short plenum. Based on the engines listed in my OP and my even more recent discovery of the P54B20 and P45B20, I'm pretty certain I'm on the right track.

To answer your question about my understanding of valvetronic, I would say yes. I think I understand it pretty well. I work on n52 engines almost every day. I have done some data viewing while abusing my cars to verify what I have read. My project car is going to a 2006 330i 6mt. So that means I'm msv70 and have the 330i AFR. I plan to develop this intake manifold before making any extreme exhaust changes to see how the ecm deals with it. I will later do a full custom exhaust and have it tuned. Hopefully by stageFP is they are still willing to tune this old junk. I've been putting some thought into measuring the piston to valve clearance and having a set of higher lift milvs made if it seems feasible. I have a parts engine and usually a spare engine on hand.

[Torgus]

Originally Posted by thalastdon1985

I don't have any experience with those programs. Nor do I have a great understanding of fluid dynamics in general. My view is that the stock manifold is optimized for better torque across the range. I should have mentioned that I'm looking for peak HP at 7400-7600rpm. I believe the intake manifold to be a key factor in making that peak power in lieu of a broader torque curve. I've been a motorcycle mechanic for most of my life and have been messing with N52 e90s for a few years now. I've seen plenty of superbike air boxes which are all itb. Ever single one is larger open plenum in to a velocity stack and short plenum. Based on the engines listed in my OP and my even more recent discovery of the P54B20 and P45B20, I'm pretty certain I'm on the right track.

To answer your question about my understanding of valvetronic, I would say yes. I think I understand it pretty well. I work on n52 engines almost every day. I have done some data viewing while abusing my cars to verify what I have read. My project car is going to a 2006 330i 6mt. So that means I'm msv70 and have the 330i AFR. I plan to develop this intake manifold before making any extreme exhaust changes to see how the ecm deals with it. I will later do a full custom exhaust and have it tuned. Hopefully by stageFP is they are still willing to tune this old junk. I've been putting some thought into measuring the piston to valve clearance and having a set of higher lift milvs made if it seems feasible. I have a parts engine and usually a spare engine on hand.

ITBs would be ideal but $$$.

https://www.onpointdyno.com/making-p...dyno-timeline/

https://www.enginelabs.com/engine-te...%20the%20world.

Tapered log style manifold with v stacks based off the floor, short runners, oversized TB. That should do it but is only one piece of the puzzle. You need custom cams etc. depending on your goals.

[Biginboca]

Based on dyno’s I’ve seen of N52 engines with N54 manifolds and various headers on them I think the ideal set up would have runners 1/2-1” shorter than N54 runners, because on stock diameter headers the n54 manifold dyno’s peak around 7000-7200rpms. So a little shorter would move the peak a little higher.

And then there’s the guy from r3vlimited who has posted on here a bit with the e30 and n52 swap who made power higher up but he had modded s54 headers fitted with his N54 manifold. The S54 headers are slightly larger diameter than all the n52 headers currently on the market.

So I would say shorten the runners a little more than n54 runners and open the headers in diameter slightly more than stock headers (like S54 diameter which is an engine that peaks in power around 8000rpms).

Those are my thoughts for optimizing the airflow for 7500rpms peak power on a N52.

[thalastdon1985]

Originally Posted by Biginboca

Based on dyno’s I’ve seen of N52 engines with N54 manifolds and various headers on them I think the ideal set up would have runners 1/2-1” shorter than N54 runners, because on stock diameter headers the n54 manifold dyno’s peak around 7000-7200rpms. So a little shorter would move the peak a little higher.

And then there’s the guy from r3vlimited who has posted on here a bit with the e30 and n52 swap who made power higher up but he had modded s54 headers fitted with his N54 manifold. The S54 headers are slightly larger diameter than all the n52 headers currently on the market.

So I would say shorten the runners a little more than n54 runners and open the headers in diameter slightly more than stock headers (like S54 diameter which is an engine that peaks in power around 8000rpms).

Those are my thoughts for optimizing the airflow for 7500rpms peak power on a N52.

This is pretty much my line of thought as well. Though looking at the air collector on the s52 or s50b32 euro, it effectively has a longer runner length than I think the n54 does, but I've only seen pictures of it. I wasn't planning on trying to learn about fluid dynamics or try to calculate optimum length using a formula. My plan is to make something similar in design to the above mentioned intake tracts and I believe it will more than likely make more power. It would have to be more optimal than the n54 manifold and it definitely makes more peak power. I found more posts relating to my theory buried in the n52 engine build thread, so it turns out it still being pursued by the other poster. Kind of hoping he chimes in but I don't want to call him out.

[thalastdon1985]

Originally Posted by Torgus

ITBs would be ideal but $$$.

https://www.onpointdyno.com/making-p...dyno-timeline/

https://www.enginelabs.com/engine-te...%20the%20world.

Tapered log style manifold with v stacks based off the floor, short runners, oversized TB. That should do it but is only one piece of the puzzle. You need custom cams etc. depending on your goals.

Your description sounds on point, and while I know there are improvements to be made elsewhere, the intake system alone has a large part in the power output.

[ornicar]

Originally Posted by thalastdon1985

Your description sounds on point, and while I know there are improvements to be made elsewhere, the intake system alone has a large part in the power output.

Nothing exist plug&play?

if someone launch a group buy, i will gladly be part of it.

[Torgus]

Originally Posted by ornicar

Nothing exist plug&play?

if someone launch a group buy, i will gladly be part of it.

The problem is cost. Just to build a 1 off would probably be 2-3k from a reputable shop. The $/watt is VERY high. Better off installing a SC

[hassmaschine]

Originally Posted by Biginboca

Based on dyno’s I’ve seen of N52 engines with N54 manifolds and various headers on them I think the ideal set up would have runners 1/2-1” shorter than N54 runners, because on stock diameter headers the n54 manifold dyno’s peak around 7000-7200rpms. So a little shorter would move the peak a little higher.

And then there’s the guy from r3vlimited who has posted on here a bit with the e30 and n52 swap who made power higher up but he had modded s54 headers fitted with his N54 manifold. The S54 headers are slightly larger diameter than all the n52 headers currently on the market.

So I would say shorten the runners a little more than n54 runners and open the headers in diameter slightly more than stock headers (like S54 diameter which is an engine that peaks in power around 8000rpms).

Those are my thoughts for optimizing the airflow for 7500rpms peak power on a N52.

Yeah, that's my buddy's car. I've driven it, it's fast!

It helps of course that the E30 weighs 1000lbs less than a typical E90, lol.

I'd just do N54 manifold. unless you're seriously modding the internals, it's effective and cheap. plus you don't lose the throttle, which is an important failsafe.

[Biginboca]

Originally Posted by hassmaschine

Yeah, that's my buddy's car. I've driven it, it's fast!

It helps of course that the E30 weighs 1000lbs less than a typical E90, lol.

I'd just do N54 manifold. unless you're seriously modding the internals, it's effective and cheap. plus you don't lose the throttle, which is an important failsafe.

I totally agree. I looked at modifying a IM to make shorter runners and gave up on it, too much trouble when you can get a N54 for $75 and it’ll almost bolt right up

[Torgus]

One of you NA guys can have mine for free once I swap it out this spring. Boca you get 1st dibs if you have a need.

I picked up one of these so I can run port E85: https://precisionraceworks.com/colle...39770845905089

[Biginboca]

Originally Posted by Torgus

One of you NA guys can have mine for free once I swap it out this spring. Boca you get 1st dibs if you have a need.

I picked up one of these so I can run port E85: https://precisionraceworks.com/colle...39770845905089

Hey man, that’s awesome! I actually do have a need I wanted to make a full tutorial for the swap consolidating all the info from my threads because I get a lot of PM’s asking questions.

So I needed a manifold to make the forum tutorial. I actually already have a car lined up to show the swap on also. So that would be great man, thanks!

[Torgus]

Originally Posted by Biginboca

Hey man, that’s awesome! I actually do have a need I wanted to make a full tutorial for the swap consolidating all the info from my threads because I get a lot of PM’s asking questions.

So I needed a manifold to make the forum tutorial. I actually already have a car lined up to show the swap on also. So that would be great man, thanks!

Well the moment it get's warm enough to start working on my car I'll swap the IM etc. I have a lot of other parts to do at the same time but it should all go hopefully rather quick.

[thalastdon1985]

Originally Posted by hassmaschine

Yeah, that's my buddy's car. I've driven it, it's fast!

It helps of course that the E30 weighs 1000lbs less than a typical E90, lol.

I'd just do N54 manifold. unless you're seriously modding the internals, it's effective and cheap. plus you don't lose the throttle, which is an important failsafe.

Glad you made it. You have some posts from just last year where you seem to be pursuing the same idea. My only costs will be materials and time. I think that even underdeveloped, it will be still be at least a little better than the n54 manifold. And I'm not losing my throttle body. I've read the thread on the e30, along with most of your posts, and Big's, even Torgus who I expected to show up and troll me but he didn't.

[Torgus]

Originally Posted by thalastdon1985

Glad you made it. You have some posts from just last year where you seem to be pursuing the same idea. My only costs will be materials and time. I think that even underdeveloped, it will be still be at least a little better than the n54 manifold. And I'm not losing my throttle body. I've read the thread on the e30, along with most of your posts, and Big's, even Torgus who I expected to show up and troll me but he didn't.

I can

[thalastdon1985]

Originally Posted by Torgus

I can

Oh, I'm very aware.

[thalastdon1985]

Alright, so I'm not so sure that a short as possible runner length is the answer. I believe there is something related to air velocity that can only be accomplished in a naturally aspirated engine via some intake runner length.

I have attached an image of the P54B20 race engine and a view of the inside of the air collector on the S54 engine. Inside of the air collector for the S54, there are velocity stack style runners that are about 140mm long. That measurement plus the length of the throttle body itself would be the intake runner length at WOT. I suspect that total length will be very close to the runner from plenum to head on the N52 manifold. The conclusion I draw from this is that the plenum size is what needs to be addressed as opposed to runner length. Thoughts?

[Torgus]

In general what I remember is the NA thought is long runners are better for low end tq. Short for high end. At least this is what you saw in most OEM street vehicle manufacturers over the years, or I should say, I have.

Bespoke race engines are their own separate entity as they are usually designed to rev high and only be used in the upper 1/3 of the rev range and are not built for longevity, just to survive the race or part of the race season. No one cares if it runs like shit at lower RPMs. The cams, head, plenum, ITBs, cams, headers, etc. are all designed for max high RPM HP production and nothing else. Also, usually are restricted in some form by the governing body of the class they are trying to run in. Which is why you see restrictors used. Look at the TINY air restrictors: https://f30.bimmerpost.com/forums/sh...php?p=21623349

There is some black magic about intake resonance waves(like exhaust) etc and having the right runner length with a trumpet spaced off the floor in a plenum etc. This way the resonance wave hits the back of the valve as it is opening and pushes in a 'little' bit more air than otherwise. The math is complex and I doubt any of us can do it or want to. I believe is is also is related to your cam profiles, rpm, and exhaust scavenging aka it all works together. That same manifold on another NA engine might actually perform worse because everything else after it is not optimized.

The n52 is an bmw economy NA engine. It is VERY good at what it does. Trying to turn it into something it is not is likely a waste of both time and money. If you want a high reving NA engine there are plenty to choose from even some from bmw which you could 'drop' in. If you are serious about the n52 and have lofty NA HP goals what you need is to figure out what you can max rev it to before it destroys itself. I don't even remember if it is under or over square in design. NA(Even FI) needs revs to deal with lack of displacement. Look at bikes. Reving to 12k from the factory. Get the 52 reving to the moon, then have some one design custom cam shafts to go with your custom plenum. It's a lot of work, time, and money when you can drop in another engine that that has already all been figured out on. All of this work is probably not worth it unless you have to keep the n52 engine for some reason to run in the class you want to.

Too bad Pete is not around. I am sure he could add to this discussion.

For 99.9% of owners stock or the n54 manifold is probably the way to go all things considered.

Personally, I'd like to see an affordable turbo kit come out for the n52. The SC is limited given it's size.

[thalastdon1985]

I'm not currently interested in forced induction. I'm looking to make peak power at 7400-7600. My goal is a stripped down e90 that weighs in around 2800lbs and makes 280whp or more. I'm not racing, just trying to have a good time. I'm aware of the limits of the n52, but I'm also aware that the stock manifold limits it peak power potential and the n54 manifold is FAR from optimal. That P54B20 engine peaks at 8500, has fairly long runners and a very large plenum. It's restriction is at the throttle body itself, but there is a lot of air available right past that. Why do you think the air collector is designed the way it is on the s50b32 and s54? I think it's to have large amount of air available and the runner length is to allow more air velocity. 12k is low for motorcycle stuff these days. But motorcycle intake tracts have always followed the same idea even when they only turned 9k. It is essentially the same idea as the s54 and other engines I have referenced.

[Torgus]

Originally Posted by thalastdon1985

I'm not currently interested in forced induction. I'm looking to make peak power at 7400-7600. My goal is a stripped down e90 that weighs in around 2800lbs and makes 280whp or more. I'm not racing, just trying to have a good time. I'm aware of the limits of the n52, but I'm also aware that the stock manifold limits it peak power potential and the n54 manifold is FAR from optimal. That P54B20 engine peaks at 8500, has fairly long runners and a very large plenum. It's restriction is at the throttle body itself, but there is a lot of air available right past that. Why do you think the air collector is designed the way it is on the s50b32 and s54? I think it's to have large amount of air available and the runner length is to allow more air velocity. 12k is low for motorcycle stuff these days. But motorcycle intake tracts have always followed the same idea even when they only turned 9k. It is essentially the same idea as the s54 and other engines I have referenced.

Well it sounds like you have it all figured out?

2800 is a GUTTED e90. Literally nothing left except a sheet metal chair. No interior, sound deadening, etc. Going to be miserable to drive on the street unless you have ear plugs in etc. Have fun!

Also, SC n52 routinely put down 280whp. You are going to do that NA? I'm talking dynojet corrected not some random dyno pretending to measure crank or an engine dyno. Let me know when you get there and how much it costs.

We have ALL heard this many times before. No one ever gets there. The intake plenum is the least of your worries IMO.



Can you spell out to us how you plan on achieving 280 whp on a dynojet SAE corrected on an n52? I am sure everyone would be interested in hearing the path forward. Myself included.

[hassmaschine]

FYI, don't forget the N52 runners are partially built into the head. So the N54 manifold actually ends up with a longer runner length than you'd think - it's been a while since I looked, but a good 1.5" of the runners are cast into the heads themselves.

My friend's N52 swapped E30 did 268hp at the wheels with S54 headers and the N54 manifold. It is otherwise completely stock (no MILVS, cams or anything). It made closer to 280 without the MAF, but we had issues tuning the O2 feedback loop with the S54 headers and abandoned that (it ripped at WOT, but everything else suffered due to PID-loop issues). In a car as light as the E30, close to 270whp is plenty good enough. He could do MILVS and other mods to get closer to 280 again, if he felt that it was worth the trouble.

I actually think getting a street E90 down to 2800lbs would be harder than getting 280 out of an N/A N52. You are on the right path that the engine needs to rev - the math is pretty simple. 3 liters, a high VE ratio, and higher rpm = more power. Nobody ever gets there with a regular E90 because they're all either running the stock N52 manifold (which physically can't make power past redline) or they're automatics/awd. You're naturally not going to match an S54, of course - it has more displacement and much more lift/duration. But the two engines have a lot more in common than you'd think (the port design on the head, for one).

Also, those supercharger kits are a poor benchmark. ESS could never figure out how to tune it properly, so they clipped the MAF wire and basically ran it in limp mode. Numerous people had tons of issues with those kits regarding tuning. Do they even sell those anymore?