The intake system on the M44

[jimmypet]

Hey Guys,
I just tore into my Ti for the first time basically just checking it over, checking air filter condition, vacuum hose condition, looking for cracking and rot.

I just had to come post,,, what the hell were Hans and Franz on when they designed the intake system for these cars???
That has to be the most convoluted way of getting air into an engine I have ever seen.

The whole up and over the radiator thing,,, crazy.

Anyone know the reason for all that?
They could have just taken air from right behind the left headlight.
It even looks like there is a port for it.

I am tempted to try to simplify.
You have to take alot of stuff off just to change the air filter.
Just doesnt need to be that complicated.

Anyone else think that?

[cooljess76]

I think the factory airbox is very well designed. 100 times better than any cold air intake or short ram garbage. You literally don't have to remove anything to change a filter. Just pop the four clips, lift the lid and swap the filter. Do some research, you'll find that several people have hydrolocked their motors with CAI's and there's little IF ANY horsepower to be gained. People do it solely for looks and sound(which on a 4 banger sounds silly anyway) and IMHO I just don't think it's worth the risk of having water sucked into your engine. I work on a lot of cars and I've owned a lot of cars. Every time I see a CAI or some POS "racing" filter, I automatically think RICER and giggle. I usually won't even purchase a car if it has one of these things installed(unless I'm getting it for a super good deal) because it tells me that the owner is probably a kid who doesn't know anything about cars, dogged it and didn't maintain it well. Paper filters are cheap, they've been proven to flow better and as for the foam snorkel, it's a factory cold air intake. How many cars can you say that about? Take a look at the passenger side of the engine, you'll see that it has a really nice factory header. How many cars can you say that about? Should you ever need to remove the snorkeldick, it's only two screws and a clip. Do what you like though

[jimmypet]

I'm not talking about gaining horsepower,,, the system is just over complicated.
I just don't get all the extra plastic.
The design makes little sense and the engine compartment unnecessarily cluttered.

Why not have the inlet right in front of the air box taking the cold air from right next to the rad?
All the E30 M3s had that exact inlet directly in front of the air box straight into the rad support, drawing cold air from behind the bumper.
Worked pretty well on those.

The extra complication of going up and over the rad makes no sense.
If one were to hydrolock an engine with the inlet in the front of the existing air box,, the car would also need a periscope. Its at the exact same level as the existing inlet only on the correct side.

What is the purpose with that whole "extra" box hanging off the side of the air box??

The other thing thats crazy about these is that the foam insulation at 14 years old is completely degrading and turning to dust, but there does not appear to be any way to remove the plastic retaining screen to remove it before it gets sucked into the engine (without breaking the air box).

BMW could have made the system so much simpler and yet retained the function.

[rochey6957]

the M42 air intake gets the air from behind the driver headlight. Just as you are describing with your simplification. Google the the engine bays and compare the pics you will see what i mean. I agree the air going over the radiator is unnecessary, but it probably makes the engine bay look more balanced. Also, with the ASC and Cruise Control components right there it might have been hard to fit the snorkel behind that headlight with the larger M44 airbox. The m42 however has a smaller filter box all together. So you might want to play around with those different setups.

The extra hanging part is a resonator to decrease intake noise(if there even is any). And that insulation... Just rip it all out even the screen too. Its pointless when its so degraded and it will get sucked into the engine.

[cooljess76]

The foam should indeed be removed. I beleive it was put in there to a) reduce temperature and b) reduce noise. But yes, it does tend to fall apart and that is not good. IIRC, the inner "cage" does come out. I know I removed mine when I cleaned the foam out. For whatever reason BMW engineers decided to route air from the passenger headlight, I do not know. Perhaps they found that by doing so, the air is cooled more effectively, pehaps they determined that it would take more water to actually reach the air filter, perhaps it has something to do with volume, charging, flow or emissions, who knows. All I know is that the team of individuals that engineered these vehicles have higher credentials than me. I'm sure a lot of research went into developing the most efficient aspiration and for them to install these components on hundreds of thousands of vehicles, they must have had substantial data to back it up. There's probably a lot of things that are unecessary and there's certainly a lot of things that BMW could have done to make these cars better. They could've offered them with 17" wheels and M Series powerplants. They could've offered them with Mtech sideskirts, mirrors and vader seats. It all boils down to them finding a balance between comfort, performance and efficiency as well as being able market it within a particular budget. The e36 compact was marketed as a sporty yet stylish ECONOMY car.

[jimmypet]

Hey Guys,
So I had another session with my Ti today.
I took some advice from a few hours searching the forum.
Here is what I did.

- I replaced my secondary throttle with a new non-DSC boot.
- I took that whole passenger side intake contraption off, ported the stock air box forward like a stock E30 M3 box taking cold air from behind the headlights / bumper.
- I took that ridiculous side extremity off the air box and plugged its hole.
- I took the side inlet snout off the lower air box and plugged its hole.
- I took that whole rotted 14 year old "octopus" off the fuel injectors, capped everything.
- I took the Air Pump thingy off, capped everything.
- I gutted all that plastic caging and disintegrating foam from the insides of the air box.
- Took the disintegrating base model rubber steering wheel off and replaced it with a spare Momo Type 78 I had from one of my race cars.

Now the intake tract is GREATLY simplified, I can actually see the engine, someone whenever I sell the car will get a brand new air pump if they want it.

The car idles great, and over all just feels a bit snappier.

I have a feeling I was getting some vacuum leaks from some of those 14 year old rubber intake items.
I have not deeply inspected all the stuff I took off but most of it crumbled when I touched it.

I fear my 14 year old motor mounts are suffering the same fate as most of the rubber I took off, that feels a little jiggly. I'll post the results of that operation in the proper area.
I'm going to go with M3 mounts in that place and likely Rogue trans mounts unless I can find something else used on the forums.

I have a set of Bilstein sports, Eibach sport lines and Turner RSMs in line to go in as soon as I get my race car off my lift.
At the same time I'll hopefully do the engine, trans mounts and refresh the shifter bushing parts.

Then this little guy should be a great little roller-skate. I really like the car.
It was well cared for by its previous owner, just needs a little tightening up. 14 year old rubber just needs replacing.

Thanks for you guys having a great forum here, a storehouse of information that I can hopefully add to over the coming years.

I'm very active in the E30 M3 forums, I hope to learn enough to contribute the same here.

Cheers
jimmy p.

[tmjns796]

I think you should start up a build thread, What cars do you race?

[jimmypet]

Originally Posted by tmjns796

I think you should start up a build thread, What cars do you race?

I'm a terrible "documentor",,, I restored an entire ex-Prodrive BTCC car and literally took about 20 pictures during the 2 year process. So I fear a build thread would be boring for people.
The Ti I bought will be a commuter / driver,,, I just like things probably a bit "tighter" than most would for a commuter car. I'm basically just doing a freshen up of what are probably still original parts to tighten the thing up a bit.
"While Im in There" I'm just choosing to replace the stock components with sportier versions.

I have 2 E30 M3 race cars, 1 is a US spec car that is primarily set up now for SCCA SPU (a regional catch all Production class, stands for Super Production Under 2.5 litres).
As I mentioned above I also have an ex-Prodrive BTCC E30 M3, that was driven by Frank Sytner in the BTCC in 1988 season that I have restored for vintage racing (and whatever BMWCCA track days I can). I like to take that one to events where people get what it is and the historical significance of the car.

I posted some pics in another thread:
http://www.318ti.org/forum/showpost....64&postcount=8

Back on topic, I just drove the car 120 miles this AM to a job site.
It now is absolutely peppier and more responsive than it was before what I did. I know people say that inlet mods dont add any HP,,, but the drivability profile has changed noticeably on mine. Maybe I had vacuum leakage. Not sure, but it for certain feels better.
And as a side benefit,,, its got a little intake sound now!!!
Kinda cool.

[Noneone2]

I did a similar airbox conversion; pulling air from behind/ next to the driverside headlight not only to simplify but now the power steering reservoir is visible and accessible. This is one fluid that is probably overlooked more often than not.
Jess, I agree with you about the engineers that designed our beloved Ti's. This I found out the hard way via experimentation ie failures, during my air-cooled VW days many years ago.

[jimmypet]

Yeah, it makes it so simple doesn't it?

I'm curious about all the talk on this forum about "Hydrlocking".
What makes the Ti supposedly so susceptible to Hydrolocking that the E36 does not?

I know about 100 people with E36s and I have never heard one of them ever mention hydrolocking, but I must have seen mention of it in 50 posts on this board.
As I was researching I saw so many posts of people worried about hydrolock?
Are our members traversing streams in their Tis?

[bullmand]

I think that's probably because there have been a couple of infamous cases of people here with lowered cars and questionable aftermarket intakes managing to get water in them. It seems like most of the less expensive "cold air intakes" end up sticking the filter down near the brake ducts in the front bumper and it's down hill from there.

To the point of your original question, the early tis with the M42 and maybe even some of the early M44 models had the snorkel that runs directly from behind the headlight into the front of the airbox. My understanding is that it was lengthened and sent to the other side for noise abatement. Years ago I modded mine to use both intake paths and it works just fine. I have no idea if there's any improvement in anything with that set up, but it was about $13 in parts and a couple hours of time. You wouldn't know it was there if I you weren't told. There's a write-up about it in the notebook section.

[jimmypet]

I'd probably add "questionable driving judgement" if you are hydrolocking a car.
Its an e36, not a Range Rover.

I just did 250 miles with mine this weekend for work.
I 100% believe the car feels more responsive now with the inlet mods and cleaning up of the vacuum system,,, AND I love the addition of the intake sound as you dip into the throttle.
It really seems like BMW went to great lengths to neuter this little car from sporting sounds with that M44 inlet system. I wonder why.

[tiFreak]

I did the same thing on my track car, I actually had the M42 airbox off my other car so I just stuck it in. works great and didn't cost me a dime

[cooljess76]

HuGo, Marv17 and PettitWC are three that come to mind right away. There were a couple others on this forum who hydrolocked their engines due to CAI's, but these guys stand out in my mind because we all used to hang out together and worked on eachother's cars. HuGo was just driving in the rain, Marv drove through a puddle and Chris(PettitWC) got stuck in a flood when he was moving cross country. None of the cars were ridiculously low. Marv and Hugo were on Billie/H&R sport while Chris was on Racing Dynamics(about the same height). IDK why or if anything makes the ti more susceptible than other e36's. All I know is that it happened, it sucks and it's just not worth it IMO. If they offered substantial performance gains or better fuel economy, maybe... But to do it just for looks and a slight change in sound, nah I think I'll stick with a factory airbox.

FWIW, when I picked up my old clubsport it had one of these rigged up to the airbox. C'mon!

[JdevTi]

I haven't taken the intake out myself to see what all is there, but a couple things I have learned/know:
*The cage that holds the upper foam in the airbox is removable
*regarding: "- I took that ridiculous side extremity off the air box and plugged its hole."
That's a resonator. It helps divide or amplify sound wave pulses from engine. It may have something to do with audible sound pulses for the driver's benefit, and/or to compliment the intake manifold.
*Personally, I like the look of the clean engine compartment. It looks like they went the extra mile to make it look finished.

I respect people who go in head first because they can get a lot done, but like Jess eluded to, people with "common sense" often make poor engineers because they don't understand the entirety of the system they are redesigning. Sometimes budgetary issues cut engineering departments short, or rush products to market, and unfortunately we don't easily know what was designed for a deliberate purpose or is bad design. Hopefully your car runs better now for the right reasons though...