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      06-04-2016, 05:39 PM   #1
Sales@RKautowerks
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Drives: e92 m3
Join Date: Aug 2013
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M6 intakes carbon fiber RK autowerks

Hey guys!

I've been working on these intakes the last couple of months, done a lot of testing and finally got the first pieces in today!

The intakes were produced using state of the art methods from start to end.

1) 3d scanned stock airboxes to ensure fitment is like a glove.
2) 3d scanning ensure the MAF calibration is not tampered with.
3) CFD to ensure the flow was optimized and nothing left on the table.
4) 3d printed to check fitment, flow tested, dyno tested.
5) CNC carbon fiber molds
6) Autoclave carbon fiber production

I'm going to reserve some space for dyno results, i have the prototype intakes dynos, we were hitting abotu 600-625whp with a tune and downpipes. But that's not a final number by any means, the testing was more durability and heat soak, not numbers.









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I'm sure all you guys want dyno graphs, but humor me for a bit, i feel the flow numbers are what you guys should focus on, well not just flow number but flow numbers as a function of delta pressure. So i'll give you guys a brief explanation on how intakes actually "make" power as you guys like to put it.

I'm sure you've heard that intakes make power, that's a not exactly true, intakes don't make power at all. They FREE up power, the engine is already producing what it can produce at its RON(gasoline) knock limit provided a chain of other criteria are not holding it back. As an OEM(i work for an OEM) we design intakes very differently than the aftermarket, we have noise, vibration, power constraints, costs, and durability in mind. A combination of these constraints are why we leave "power" on the table. In the aftermarket the consumers are usually power and aesthetics drive, not so much concerned about the other constraints.

So with that said, the intake system is purposely constrained from factory. The ECU is calibrated with the intake system and it's shipped off.

So how do you "free" up this power?

The common assumption is that your intakes make power, false. The governing equation/theory/facts behind this is BMEP = IMEP + PMEP + FMEP. Where BMEP is the brake power, the power the engine will produce at the crank rather. Now you have IMEP, the indicated mean effective pressure, the power loop of the PV diagram. This is where the magic happens, IMEP is the boom inside the engine, the working portion of the PV diagram. This is the absolute amount of power the engine can make before it starts sending the power in all sorts of direction. PMEP is where the intakes come in, PMEP is the pumping mean effective pressure. The engine has to utilize some of its IMEP to suck in the air and push the air out, this isn't free after-all. Then you have FMEP, the friction portion of the game, this is your rotating assembly, lubrication, seals, and etc.

Here's a PV diagram to visualize what's going on.




BMEP = crank power = measured using a dyno
IMEP = power loop = measured using in cylinder pressure transducers
PMEP = pumping loop = measured using in cylinder pressure transducers
FMEP = friction = calculated using math by knowing BMEP/IMEP/PMEP

So now that we've established power is only made in the power loop, everyone should be onboard with why intakes don't make power.

Intakes are like straws, us as a humans can suck in x amount of water using a straw that is half an inch wide, we can also suck x amount of water with a straw that is 4x as small. It's easier to drink through the bigger straw right? Same concept with an intake! Which brings me to my next point, an efficient intake is like a big straw, really easy to suck the water through. We call this value "delta pressure" the amount of suction needed to move a certain amount of fluid through a vessel.

With that said, you want to make it easy for the engine to "breath" on a forced induction application, easier for the engine to breath means less power it has to use to suck that air. See where this is going?

Lets put some numbers with our equations.

BMEP = IMEP + PMEP + FMEP
(+) = (+) + (-) + (-)
(end power) = (total power) + (pumping loss) + (friction loss)


BMEP = IMEP + PMEP + FMEP
10 = 14 + (-2) + (-2)

That is configuration A

now we have our new intake, configuration B, the big straw

BMEP = IMEP + PMEP + FMEP
11 = 14 + (-1) + (-2)


You just increased the crank power of the engine, by freeing up power that was always there! This is why when you see flow in LPS, it doesn't hold much value, so you increased the flow? Does it mean anything, because the flow has to have some type of delta pressure associated with it, how much suction did you need to produce that flow. I can take a 2" pipe and flow 500LPS through it, but i had to have a ton of suction on it. But my 3" pipe only flowed 300LPS, but it was barely sucking. Marketing will make you think the 500LPS is better because well...you didn't know, now you do!


With that said, i ran the flow numbers and will demonstrate why our intakes will produce an increase in power.

This graph shows the amount of air an engine is consuming based on your boost pressure (turbo application only). This gives you an idea of how much air your engine is consuming at wide open throttle at a certain RPM.


Now you have what most are used to seeing, the "flow increase" diagram. I have my X axis as a function of delta pressure, which is what you should ask for. But like we discussed earlier, this doesn't help quantify why engine is making more power. You see that you increased flow at each delta pressure, but you don't know what the delta pressure drop is, just what you increased flow by.


This is why you should ask the vendor for this graph. A chart of delta pressure as a function of flow. Now you can quantify, based off how an engine works as explained above, what benefits to expect to see. You can see for yourself in the chart below how this compares. Referencing to my cylinder head flow chart and comparing what delta pressure benefit you have based off the RPM at WOT condition. You can see below how my intakes compare to a competitor and how they compare to stock. I've reduced your pumping loss up to 40-60%, power you were allocating to move the air into the engine before, is now being used to move your car! The lower your delta pressure, the better.



Reason why i bring that up is because it's really easy to quantify the difference between intakes when you conduct testing using a flow bench. It's not easy to compare intakes or really quantify power differences on a chassis dyno because you have so much going on that needs to be accounted for. You need a bench dyno running some state of the art equipment to truly quantify it, stuff i do at work. The flow bench is something anyone who's charging someone several hundreds for an intake should use to validate their product. You can make this entire system go full circle and derive a correlation between delta_P reduction and the pumping loss benefit if you had a system sophisticated enough to accurately capture the PMEP inside the engine. Then you could back out the increase in power as a function of Delta_P. You'll be hard pressed to find shops outside the OEM that have this capability, i know of a handful. Happy modding!

These are currently for sale at $1850 + shipping!

Follow us on facebook or check out our website for more products coming soon!

www.rkautowerks.com
https://www.facebook.com/RKAutowerks/

Thanks!
-R
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