Benefits of Ram Air Intake?

I'm looking to put in something to improve airflow in my '08 E90 335i.

I really like RPi's Ram Air Induction V3 found here. I was wondering if you guys could provide any insight as to whether or not it'd be beneficial to my car, i.e. improve air flow, help with cooling, differences in idle'ing (if any).. This would be one of my first DIY projects on this car, so I'm really looking forward to it if it's worth pursuing.

Thanks!

Originally Posted by DT335

I'm looking to put in something to improve airflow in my '08 E90 335i.

I really like RPi's Ram Air Induction V3 found here. I was wondering if you guys could provide any insight as to whether or not it'd be beneficial to my car, i.e. improve air flow, help with cooling, differences in idle'ing (if any).. This would be one of my first DIY projects on this car, so I'm really looking forward to it if it's worth pursuing.

Thanks!

If these have any benefit, it is only at speed. Does nothing for idle, does nothing for cooling. Their function is simply to "scoop" more air while driving at speed. As you can see the claimed HP increase is with a fan. And that claim is on an M3, which is NA. My feeling is that on a turbo engine like the 335, you'll have little if any noticeble difference. As you can see I have it on my Z, which is NA. And I got them for a lot cheaper than that price.

Thanks a lot.

Originally Posted by DT335

I'm looking to put in something to improve airflow in my '08 E90 335i.

You'll need other mods to make use of it. What have you done?

If nothing, do not install ram air intake. BMW engines are engineered very specifically - modding must be done with a level of technical knowledge or....it's expensive....

Originally Posted by LarkHouston

If these have any benefit, it is only at speed.

+1

But please don't pay $99!

http://www.e90post.com/forums/showthread.php?t=289187

Wallet pain but no gain. For stock & light mods BMW's are pretty well engineered right out of the factory. Personally I would have to wonder what if anything they can add when the intakes are in a high pressure area to start with.

bear -

I was thinking the same myself. Just a little skeptical on doing light modding, but I'm curious, nonetheless.

I've got a list of things I'd like to do cosmetically to the car, I'd probably be wise to start there...

Originally Posted by bear-avhistory

Wallet pain but no gain. For stock & light mods BMW's are pretty well engineered right out of the factory. Personally I would have to wonder what if anything they can add when the intakes are in a high pressure area to start with.

The intakes on the 335 and Z4 are completely different. The reason I spent the $40 bucks for the Z4 is because the intake is perpendicular to the right side of the radiator (as you look face on or drivers side) and that intuitively seemed to call for a scoop which was face on and "scooped" the air towards the intake. I may be all wet but it makes me feel better.

We used to see a lot of that with "Ram Air" systems in the muscle car era when people were we just starting to learn about how aerodynamics effected air flow into the induction system. Lots of cars like my Tri-Power Ram Air GTO got it wrong (but the CAI part was right) while the 442 ram air with scoops under the front bumper & big block Chevelles' with cowl induction got it right both from a ram air & a CAI approach.

Lots of this stuff was all about styling so many muscle cars with intakes in the middle of the hood got it wrong unless they were pretty tall & got out of the boundary layer.

EDIT: For a mid hood scoop that actually worked look at Sox & Martins' HEMI race car.

Originally Posted by LarkHouston

The intakes on the 335 and Z4 are completely different. The reason I spent the $40 bucks for the Z4 is because the intake is perpendicular to the right side of the radiator (as you look face on or drivers side) and that intuitively seemed to call for a scoop which was face on and "scooped" the air towards the intake. I may be all wet but it makes me feel better.

I have not seen a Z's intake system but I would guess that at worse you did not hurt anything, so for $40 if you are happy, Enjoy

Is ram air effective with forced induction? Even at speed? The 335 airbox seems generous enough to not warrant forcing air into it.

Originally Posted by thekurgan

Is ram air effective with forced induction? Even at speed? The 335 airbox seems generous enough to not warrant forcing air into it.

How about 'maybe'. I am sure the pros selling product might jump on my butt but I think the answer is how many CFM of air does the turbo need when its maxing out its ability to pump air at the required boost level for the mods you have to perform at their maximum potential.

Once you have that number you need to check the intake tract to see if any portion of it can’t support the required airflow. If the tract is just OK or has a little bit of a restriction then forcing air under pressure into it can help. If the tract is just plain too small even with some ram air to move the number of CFM of air required it really needs to be replaced with something with the ability to flow air with out restriction.

Bottom line is I think you need a reasonable amount of WHP 400+?? to think about the issue & most of the scoops being sold only effect how the car looks.

Originally Posted by LarkHouston

As you can see I have it on my Z4...

[Slightly OT]:

Lark, how come I never see you on the Z3/Z4 forum on Bimmerfest or on Zpost?

We've both got roughly the same model cars!

[/back on topic]

Originally Posted by DT335

I'm looking to put in something to improve airflow in my '08 E90 335i.

I really like RPi's Ram Air Induction V3 found here. I was wondering if you guys could provide any insight as to whether or not it'd be beneficial to my car, i.e. improve air flow, help with cooling, differences in idle'ing (if any).. This would be one of my first DIY projects on this car, so I'm really looking forward to it if it's worth pursuing.

The car controls boost by comparing boost pressure to atmospheric pressure. So if the ram air system is increasing boost, the car will open the turbos' wastegates a bit wider to reduce the amount of boost that they provide. The end result will be the same amount of manifold pressure you had before.

The turbos won't be working quite as hard, which will translate into a slight reduction in exhaust restriction, which might make for a slight increase in power. However, I don't think you'll be able to feel it.

Unless you're planning to build your BMW into a Bonneville racer, I think you'll be wasting your money with this modification.

This is all assuming that those scoops do anything at all. I've never seen a ram air system that had so many sharp angles on it. Ram air depends on a smooth intake that gradually widens to decelerate the airflow, converting kinetic energy into potential energy in the form of pressure. Those scoops look like a 16 year old made them.

Frederic

RAM AIR doesn't do anything on a turbo car, a free flowing intake will help the turbo's work less, but they are sucking air at a volume greater than ram air could every make any difference on. Ram Air would only help with a naturally aspirated motor by pushing in more air when the intake is under vacuum. That being said, those scoops are unlikely even to make a measurable difference at all on a N/A car.

So basically they are a cosmetic item at best and you can get them for $35-$50 from many other places if you just want them so there is something that looks red under the grill.

I am actually betting they disrupt and block airflow enough to the radiator to be detrimental overall to the car!

Originally Posted by SD Z4MR

[Slightly OT]:

Lark, how come I never see you on the Z3/Z4 forum on Bimmerfest or on Zpost?

We've both got roughly the same model cars!

[/back on topic]

I am on both from time to time. I don't usually have much to add in those forums. Plus I can hardly keep up with everything on this forum much less those too!

Originally Posted by roadkillrob

I am actually betting they disrupt and block airflow enough to the radiator to be detrimental overall to the car!

That's what I was assuming and afraid of.. Cosmetically, I think they look great being red under the grill.

If you're needing more outside air for cooling I'd be looking at larger intercoolers so that maybe I could increase the boost too