You guys are nuts.

The lower air box is prefilter. There’s no restriction there, if anything the size of the inlet tube is the only factor. It makes zero difference, it’s connected at equivalent ambient air pressure to the biggest air box in the world.... the outside. It makes absolutely no difference and you’re wasting everyone’s time “researching” further including your own. You could make that lower air box 10x as big and it will do nothing. There’s no restriction there guys, air doesn’t bump into things or decide to go one way or another or turn around and leave because of the size shape color or smell of the lower box. Seriously, get a grip.

 

I'm talking about a bigger system with bigger top and bottom along with bigger air filters.

Here is the 640hp amg gt air box and the sls air box and filter is even bigger.

think of your renntech intake with a wider air filter and a wider bottom half of the box.

 

ahahaha i know much you love thread resurrections, especially those of the intake spacer variety ;P

The airflow path of the C63 is quite complicated and convoluted - you have air flowing in so many different directions before it finally reaches its desired destination for combustion.
But perhaps we can define & model a few things.
Volumetric Flow Rate is defined by Q = Flow Velocity x Cross Sectional Area. (We will assume the same flow velocity across our comparisons below, and a flate plane cross section).
The most distal air inlet ports & air snorkels have a larger cross sectional area compared to the narrower tube that feeds the corresponding narrow inlet of lower airbox.
I contend that: Cross Sectional Area of inlet of stock lower Airbox + AFE Pro Dry S filter (in stock position), is smaller than Cross Sectional Area of inlet of lower Airbox + Spacer (or Magnuson lower Airbox).
As observed in skratch77's previous photos:

Stock Position of Air Filter in Lower Airbox (Left) vs Elevated Position of Air Filter in Lower Airbox + Spacer (Right)



Just taking (flat plane) Cross Sectional Area into account, we can see that Volumetric Flow Rate of air would therefore be reduced in the example on the Left hand side above.
OK, but the rubber surround of the AFE acts as a barrier to airflow only near the face of this inlet (and along inlet's length). This then forces air to deflect, and flow under the filter's rubber surround, and then through the filter.
This deflection complicates things, as the transition of air flow may not be smooth. Could this deflection of airflow cause unfavorable turbulence, as opposed to smoother flowing laminar flow?
It's very possible.

 

The ONLY thing that matters is the size of the filter element. That is the only determining factor on that side of the intake (given adequate flow governed by the actual opening to the airbox, which we already have). Looking at anything else is just a total joke and a waste of time. Seriously, all the info you need is a quick Google search away, none of this stupid debate is brand new to our platform. Take off the lower air box completely and see what happens..... absolutely nothing. Because the size of the filter governs flow into the engine, nothing else.

Transition of airflow and unfavorable turbulence and laminar volumetric efficiency blah blah blah. Are you even listening to yourself? Seriously guys, this is one of the dumber threads anyone who knows anything has ever read.

 

So you think a bigger bottom and bigger air filter along with a bigger top wont add any volume?

I want a bigger airbox like the ones in the sls and amg gt cars.

 

Volume to do what? The car can only suck in so much air and what's there is already over sized.

 

Then why does an sls have bigger air boxes? I'm willing to bet my car an sls would lose power if you put our row boxes on it.

Mind you my car is pretty max out and I'm looking for that last 5whp.

I have pretty much ever bolt on you can do including 82mm throttle bodies and plasma ignition coils etc.

Bigger air boxes is my next step..

 

The box TOP can make a difference, because that air is post-filter and can be post MAF. That’s where optimizations can be made to the shape, size doesn’t matter much.

The box BOTTOM, makes no difference unless you make the filter suck through a straw. The opening that’s there is more than big enough for air to get through unrestricted. Take the bottom off and see, there will be no difference. The only pre-filter modification that is proven to work is by enlarging the snorkels so they can scoop up more cold air from the front.

The FILTER is the primary limiting factor, but only materially so for high horsepower, mainly forced induction builds. Guys like Brad put larger cone filters on long pipes and route them to cold air sources. If there’s any gains at all to be had it’s by doing that, and those gains will be entirely from the larger filter element and colder air, possibly insulating the pipe as well.

 

You may actually see less performance because the bottom of the box does have some thermal protection.

 

This is exactly my point, and is illustrated by the Volumetric Flow Rate equation above, where the straw's Cross Sectional Area (and hence Flow Rate of air) is greatly reduced, when compared to the larger inlet port of lower airbox.
To use your example, the filter is being fed air, from the inlet port of this lower airbox. To extrapolate even further: Plug up and completely occlude the opening of this inlet port of both lower airboxes. What air flow will we see through the air filter?
What air flow will we see to the actual engine? The answer to both is zero (or near zero, as the system may not be 100% sealed/airtight).

Yes, the opening is "big enough" for air to flow, but I contend that we are comparing 2 differently sized openings: (1) the inlet of stock lower airbox + AFE filter in stock position vs (2) the inlet of stock lower airbox + Spacer + AFE filter in elevated position.
Compare the Cross Sectional Area near the face of both of these openings - (1) appears to have a reduced Area due to the AFE's rubber surround creating a perceived partial obstruction. But as I previously mentioned, it may not be an 'absolute' obstruction, as the air is then deflected and has to flow underneath this rubber surround, to finally flow through the filter. Does this create any possible/unfavorable turbulence that may reduces airflow rate? Does this affect performance in any real, significant way in a stock/Non-SC application? We don't know unless we test it. And as such, nobody has done an A/B comparison of (1) vs (2) to see the readings via the MAFs.

Who has done this, and recorded airflow rate? Where are the numbers? I don't think we can simply discount this lower airbox, as it directly feeds the air to the filter, and beyond.

 

Damn I hate to jump in this one but I can help clear up part of the debate. I work part time in a dyno/hot rod shop and have ran the car too many times to count. Unfortunately there's no power to be gained here. I've made runs with a homemade spacer, with air boxes turned over, and air box in tact....all within a couple hours of each other. Same weather (high 90's), same strap down. All runs were between 429 and 431. Within our dyno variance. Skratch you've got one of the baddest n/a setups on this board but I don't think this one's worth your time and money. I think you'd be better off working to isolate heat from the air box assembly with thermal tape/other means if you haven't done so already.

 

I just put 5 gallons of c85 and your kit is running good. Major mid range difference so far but afraid to try line it yet lol

 

That's because what's there is already more than enough.

A few of the other posters think you can increase the rate of lemmings going through a doorway single file on a convener belt if you widen it. If they already fit in the first place, making it wider won't do anything.

 

Great

/thread

 

Good to hear! So angry that I can't run anything more than e20 on the ttrs. Huge power to be gained but you have to add a big money secondary injection system to run full e85. There are dudes in mk3 cars cracking 9's on ethanol tunes!

You should just bite the bullet and supercharge your car.

 

Well, it doesn't do anything on the dyno, that's for sure, but at 80 mph, who knows? Airflow would need to be logged. We're not just talking about the engine breathing, but also what turbulence, if any, is caused by the filter side being in the air path when it's being "force fed" at high speed. No way to accurately measure this on a dyno. I would think you'd have to be moving a LOT of air before it could possibly be an issue though. And at that point I'd think the thin necks of the air feeders would become a restriction first.

 

Turbulence may be an issue if it was a pass through. The bottom of that box would likely always have positive pressure at 80mph even if the engine was at peak demand for air.

The supply grossly outweighs the demand.

 

I'm putting the e63 intake plenum on right now. Side by side the old one is bigger.

Anyone know wtf the vaccum box is used for? I'm going to tap it into a plastic bottle until I get another one off Ebay before breaking my original box up.

 

if “you” are right, why would Magnuson bother with making larger ones?

 

YOu need to do a back to back dyno

 

My guess is for the top to reach the new inlet pipe?

 

Guys save your time and either bend over for a RENNtech airbox, or don't bother at all.

I thought I laid this to rest a good while back anyway. The stretch in the connection to the Y-pipe essentially reduces the passage for airflow because the raised airbox upsets the fitment. My car consistenly ran with less g/s airflow with the spacer than without it. I think I posted the exact figure in Sanctown's thread in 2017 or 2018.

Also I made a very rudimentary top airbox with chopped up plastic and epoxy but didn't gain anything by way of airflow (I wanted to dyno but the machine broke when I was making my runs and gunning for dadsc63 title).

Any gains are to be had with a better neck design like what you find in the RENNtech one, which is proven to be worth 1mph in the standing quarter.

 

Which is after the TOP box post filter where the restrictions are.

There's no restrictions in the bottom.

actuallyThread/

 

Why the switch?

 

How is the Carbinio vs the Renntech? It's certainly a little lighter on the wallet.