[Biginboca]

I ran a ram intake with my factory Airbox but it was a pain because once a year I would have to remove the fender liner to get underneath and detach the ram intake before I could take the box out of the car for filter changes. So although you could do this with the US Airbox I recommend you use it with a Euro box for more convenience. They are available on overseas eBay sites for about $200 delivered.

For the actual ram parts they all can be had on amazon. My total cost for this mod is less than $50. If you have a manual and run to redline, or have done other mods which promote breathing (milvs, headers, exhaust, cat deletes) then this mod is totally worthwhile. If you have an automatic and no mods then I doubt it would do much for you.

Now on to the show...

Trace a cut out. If you are starting from scratch I recommend you leave the Airbox in the car and remove the fender liner, then mock up the 2.5” hose routing and trace on the underside of the Airbox where the piping lands. I have done this a few times so I just eyeball it



After cutting the piping should be *mildly snug* fit. The 2.5” piping tears easy so it’s better to have the fit a little loose than tight. I make the cut by drilling 1/4” holes inside the edge of my tracing all around and then sanding it smooth and round with a dremel and sanding bit





Don’t sweat if it’s not perfect, you can jam foam weather trim from Home Depot or Lowe’s into any gaps



At this point I took the liberty of covering my Airbox with heat tape. Does this do anything, who knows, but it looks cool and can’t hurt



Now back to the car. I had a blank on my bumper next to the fog light. I installed a 2.5” ID plastic flange onto it using 3m molding tape. You could use screws if you want I didn’t want to see any screws so I used the tape. I had to trim one corner of the flange. It’s only plastic. Then I opened up the hole on the bumpers blank panel using a dremel and then carefully sanding it round.







I jammed a tapered piece of silicone tubing around the flange and then used a hose clamp to tighten it around the corrugated piping



You can see it’s a tight fit with the brake duct. I’m sure you’ll figure it out lol. This is the whole run of 2.5” tubing



It helps if you have the Airbox sitting loose in the car and the fender liner removed for doing the final 2.5” piping connections. Once that is connected then replace the fender liner and move to the topside. I would recommend you attach the factory snorkels, Airbox outlet to throttle body, and then lastly bolt the Airbox back in place with the two 10mm bolts.





Enjoy your new horsepower lol

————————————————————————————————

Here’s some amazon links for the parts I used:

2.5” Tubing

POWERTEC 70198 2-1/2-Inch... https://www.amazon.com/dp/B01N0RH9PH...p_mob_ap_share

Heat Tape

Design Engineering 010396... https://www.amazon.com/dp/B0039Z5TYU...p_mob_ap_share

Flat Mounting Flange

Spectre Performance 8148 Air Duct Mounting Plate https://www.amazon.com/dp/B000BPUTL4..._idAtEbSVKWY74

3M Molding Tape

3M Super Strength Molding Tape, 03616, 7/8 in x 15 ft https://www.amazon.com/dp/B0026HOTZ2..._5eAtEbMQTFAZ4

[Silnismo]

Any before and after impressions?

[freakystyly]

Thanks for the write up! Looks well done and clean! Hoping for some impressions after engine adapts to change. I've always been curious about this mod, it looks tricky to pull off without hacking things up.

Any idea if sedan has more/less space back there vs your coupe? Xenons or any other factors? I assume the only access would be from the wheel well.

Have you run the box uncovered for giggles yet? There's definitely a torque loss with it uncovered (maybe more than just heat soak), is it present with the snorkel?

[Biginboca]

I’ve been running the ram intake for over a year now, today I just swapped from the oem US Airbox to the Euro Airbox. The US Airbox is on top and the Euro on the bottom:



I did not invent this mod I’m only following in others footsteps with my version of it.

Dinan released there version of it with 2” piping many years ago and then someone else copied it as a DIY also with 2” piping and dyno’ed their set up. You will have to search for it but there’s a thread on it.

Needless to say the gains are real. The stock intake is limited by several factors, the snorkels above the grill, the charcoal filter, and the corrugated tubing With muffler that sits between the Airbox and the Throttle Body. So if you add the ram, delete the charcoal and do a high flow drop in filter, and then add the rev motoring silicone you can gain real horsepower which has been dyno’ed and proven.

The only thing that I changed today on my set up was the stock to euro airbox conversion and I notice a little extra noise but it’s negligible. I’m sure it flows better obviously the Euro Filter has larger surface area. I did calculate the surface areas of the K&N flat panel filter and the K&N Euro filter and got

K&n e-2022 euro filter ~111 square inches area

K&n 33-2332 us filter ~70 square inches area

So It’s easy to see the Euro is helpful.

I have Xenon headlights and a coupe. I can’t comment on the E90 as far as room for the mod but I believe the Dinan version of this mod fits all E9X cars for what it’s worth. Also I tried 3” tubing at first and that’s a definite no go. 2.5” tubing is the largest you can do, and 2” is easy to fit but bigger is better in my book lol

[Finngo]

Originally Posted by Biginboca

I’ve been running the ram intake for over a year now, today I just swapped from the oem US Airbox to the Euro Airbox. The US Airbox is on top and the Euro on the bottom:



I did not invent this mod I’m only following in others footsteps with my version of it.

Dinan released there version of it with 2” piping many years ago and then someone else copied it as a DIY also with 2” piping and dyno’ed their set up. You will have to search for it but there’s a thread on it.

Needless to say the gains are real. The stock intake is limited by several factors, the snorkels above the grill, the charcoal filter, and the corrugated tubing With muffler that sits between the Airbox and the Throttle Body. So if you add the ram, delete the charcoal and do a high flow drop in filter, and then add the rev motoring silicone you can gain real horsepower which has been dyno’ed and proven.

The only thing that I changed today on my set up was the stock to euro airbox conversion and I notice a little extra noise but it’s negligible. I’m sure it flows better obviously the Euro Filter has larger surface area. I did calculate the surface areas of the K&N flat panel filter and the K&N Euro filter and got

K&n e-2022 euro filter ~111 square inches area

K&n 33-2332 us filter ~70 square inches area

So It’s easy to see the Euro is helpful.

I have Xenon headlights and a coupe. I can’t comment on the E90 as far as room for the mod but I believe the Dinan version of this mod fits all E9X cars for what it’s worth. Also I tried 3” tubing at first and that’s a definite no go. 2.5” tubing is the largest you can do, and 2” is easy to fit but bigger is better in my book lol

+1

[Eagle1oh7]

I tried something like this with my AFE box and I cut a hole in the bumper and trimmed the liner. Unfortunately when I went over a speed bump the wheel came up and ripped it right out.

[Biginboca]

Here is a link to the older thread with the dyno info for the intake mods...

https://www.e90post.com/forums/showthread.php?t=1186611

[b1aze]

Originally Posted by Biginboca

Needless to say the gains are real. The stock intake is limited by several factors, the snorkels above the grill, the charcoal filter, and the corrugated tubing With muffler that sits between the Airbox and the Throttle Body. So if you add the ram, delete the charcoal and do a high flow drop in filter, and then add the rev motoring silicone you can gain real horsepower

I’d be extremely interested in seeing the difference the snorkel alone makes. You’re right, it’s been proven the charcoal delete, inlet tube and a high flow filter make measurable gains but I’m having a hard time seeing how this is opening up a bottle neck.

Don’t get me wrong, it’s a great looking DIY but if you can’t show more than a consistent 1% increase in any power metric, it seems like a waste of time and money.

[WoodE30]

How does that fit with the charge pipe? I'm assuming that a n54.

[Biginboca]

Originally Posted by b1aze

I’d be extremely interested in seeing the difference the snorkel alone makes. You’re right, it’s been proven the charcoal delete, inlet tube and a high flow filter make measurable gains but I’m having a hard time seeing how this is opening up a bottle neck.

Don’t get me wrong, it’s a great looking DIY but if you can’t show more than a consistent 1% increase in any power metric, it seems like a waste of time and money.

There’s really no way to document a 1% increase but even 1% would be 2.5hp. I’d rather have that power than the $50.

Also if you can do a mod for <$50 and get 2.5hp, well then if you could do 5 mods like that you spent $250 and picked up 12.5hp. That would give you 1mph higher trap speed on a 1/4 mile run or 1/10th second faster eta. It’s up to the user to decide if it’s worth it, but chasing these little bits got me from a trap speed of 97mph to 103mph. It all adds up and I feel this mod is a reasonable expense as far as N/A mods go. N/A power is hard to come by as you know!

For what it’s worth I have tested all the mods on my car using my Dragy timer and correcting for D/A so I feel comfortable recommending this one. There’s other mods I have done and tested which I have posted up also that were a waste when I tested them, but this wasn’t one of those.

Another thing to keep in mind the 3 popular aftermarket intakes that have dyno’ed power gains by forum users all added a second intake tract which supplement the factory snorkels.

Dinan: Ram Inlet
BMW Performance: Second Inlet from Cowl Area
AFE Stage 2: Second Intake behind headlight

So one can ponder why those companies would spend money and time engineering a way to supplement the snorkels (and one could poo poo them all as a waste of money).... or one can just duplicate or better their results for 1/10th the cost and a few hours tinkering.

[Biginboca]

Originally Posted by WoodE30

How does that fit with the charge pipe? I'm assuming that a n54.

This is the N/A forum and it’s a N52 lol. Maybe you got confused by the manifold and oil cooler, I am running a N54 manifold and oil cooler.

[WoodE30]

Originally Posted by Biginboca

This is the N/A forum and it's a N52 lol. Maybe you got confused by the manifold and oil cooler, I am running a N54 manifold and oil cooler.

Oh ok. I was tripping there. I saw the n54 air box mounts on the intake and everything. Looks good!

[W37V]

Originally Posted by Silnismo

Any before and after impressions?

Thanks Biginboca

I just did this mod and I really didn’t want to believe it would make any difference. But, it does. My father was with me in the car for the first ride and he noticed that the car pulls stronger than before I even had a chance to say anything.

Maybe it is placebo, but engine revs a bit quicker. Power is bit more linear and it seems like midrange (over 3500rpm) and top end is definitely stronger. I’m not sure how much power I got, but it feels like gains were better than when I put in my headers (since gone). Heck, it’s almost comparable to getting a new tune. I highly and definitely recommend it.

Oh, you also get slightly more engine sound, which is not a bad thing since this engine (to me) sounds awesome.

[Biginboca]

Originally Posted by W37V

Thanks Biginboca

I just did this mod and I really didn’t want to believe it would make any difference. But, it does. My father was with me in the car for the first ride and he noticed that the car pulls stronger than before I even had a chance to say anything.

Maybe it is placebo, but engine revs a bit quicker. Power is bit more linear and it seems like midrange (over 3500rpm) and top end is definitely stronger. I’m not sure how much power I got, but it feels like gains were better than when I put in my headers (since gone). Heck, it’s almost comparable to getting a new tune. I highly and definitely recommend it.

Oh, you also get slightly more engine sound, which is not a bad thing since this engine (to me) sounds awesome.

Awesome! Yes you get a bit more intake growl to go with the HP. For less than $50 it’s a great mod

[Phil325i]

Note to OP...don't ever drive through standing water!

[W37V]

Originally Posted by Biginboca

Awesome! Yes you get a bit more intake growl to go with the HP. For less than $50 it’s a great mod

To keep the cost down, I just used some duct tape to keep the hose connected to the flange and used screws to connect the flange to the plastic mesh. So, the only items that I used for this are flange and hose.

Tubing $10
Flange $4
and ducktape that I had on hand - $4

[W37V]

Originally Posted by Phil325i

Note to OP...don't ever drive through standing water!

This is BMW that is about 5 feet high. Who the hell would drive it through high water? btw water would need to be at least 2 feet with this setup to make any difference.

[freakystyly]

Originally Posted by W37V

This is BMW that is about 5 feet high. Who the hell would drive it through high water? btw water would need to be at least 2 feet with this setup to make any difference.

The standing water would have to be higher than your intake filter. Air will always choose the path of least resistance (your stock top of radiator intake snorkel).

[The Nightman]

Originally Posted by W37V

Thanks Biginboca

I just did this mod and I really didn’t want to believe it would make any difference. But, it does. My father was with me in the car for the first ride and he noticed that the car pulls stronger than before I even had a chance to say anything.

Maybe it is placebo, but engine revs a bit quicker. Power is bit more linear and it seems like midrange (over 3500rpm) and top end is definitely stronger. I’m not sure how much power I got, but it feels like gains were better than when I put in my headers (since gone). Heck, it’s almost comparable to getting a new tune. I highly and definitely recommend it.

Oh, you also get slightly more engine sound, which is not a bad thing since this engine (to me) sounds awesome.

I noticed the exact same things after installing a 3" duct on my NA airbox. Not looking forward to my next filter change

[E92William]

I did something very similar almost the same as this with my old 1.6 98 Civic. The car would top out at 105mph with the stock intake and with the ram it did 116 back to back same ambient air temperatures. That was an automatic car so there's power to be gained in all drivetrain configurations.

This mod is no joke you're literally shoving 60mph+ air into your engine, it's not a turbocharger but I verified and you're pulling positive intake manifold pressure with live data on that car while normally it'd be negative. Ofc this will vary a lot depending on how you set it up.

Imo the best way would be to run the widest tubing possible and solely use the ram part of the intake because you lose air pressure with the open area that goes into the grille scoop that could be going into the intake track.

[freakystyly]

It would need to be tested in different configurations... anyone have butt dyno results with and without ram air duct, with and without "cyba scoops", etc.


Hopefully this weekend I will finally have time to cut a hole in my euro box. I just bought a new bumper filler piece to play with for my pre-lci sedan .

[Ali-E90]

Originally Posted by freakystyly

anyone have butt dyno results with and without ram air duct, with and without "cyba scoops", etc.

Butt Dyno for Cyba scoops only, 2.5 N52 with Injen air intake (using open cone filter plus heat shield)... at low speeds, not much impact, maybe a bit freer flowing above 4.5k rpm...

at speed (50mph+?) maybe a bit of an improvement for air flow, but still hard to really confirm, but I think it's there... freer flowing above 4.5k rpm also