CP-E & K&N - Does it Really Add Power? - AcuraZine - Acura Enthusiast Community


CP-E & K&N - Does it Really Add Power?


Old 08-27-2016, 10:26 AM
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CP-E & K&N - Does it Really Add Power?

Hello everyone,

There seems to be conflicting information out there as to if aftermarket intakes actually add power. I know from another intake thread that these shortram intakes lean out the A/F ratio. Does this actually add more power to the RDX? The stock looks like it actually has a snorkel and velocity stack.

recently installed the K&N intake on the car and these are my initial impressions:

1) Sounds good
2) No increase in power or throttle response.

Any real world dyno (not from intake manufacturers) that actually show gains? Otherwise I'm thinking about removing and selling.
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Old 08-27-2016, 10:38 AM
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Butt dyno says it does . But really it's minimal if any.
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Old 08-27-2016, 06:58 PM
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COPIED FROM VIT VIPERS BLOG !!!What About Dat Short Ram Intake Doe?
Back to Honda today…

If there is one question on the interwebs that bugs the crap out of me, it’s definitely “What intake should I buy?”. Really? Come on! In this day and age Google knows that answer. So I’m not going to talk about what intake you SHOULD buy, but what intake you SHOULD NOT buy.

Short Ram Intakes Suck

Now I do realize this is a bit of a generalization as there are some exceptions (namely SRI’s designed to point at fresh air and are directed completely away from any heat sources).

Generally the SRI style intakes commonly found on the 8th and 9th gen platforms all point the filter/inlet at the back of the engine bay. This is just plain dumb. Some people will argue that the intakes do “make power” and the manufacturers claim absurd (and unrealistic) “gains” from this style of intake.

The actual FACT is these style of intakes breath hot air from the back of the engine bay — fresh air rarely, if ever, makes it to the intake and it’s pulling very hot air from an area of the engine bay where the exhaust manifold is emanating a generous amount of heat. Hot air does not make power — in fact it creates a scenario that is unsafe for optimal engine operation and you have to “dial the tune back”, something I’ll address in a bit.

The Snorkel Mod

This is a fun mod — I’ve seen this a lot and some places claim to do this to try and create “conditions similar to the street when the car is moving”. So at the heart of it they know these intakes breath hot air. This is just a cop out to “make numbers” — gotta get a print out to race the dyno sheet online, right? I don’t care about “numbers”, if my dyno generated absolutely no numbers and just a power curve I could still do my job. We sell tunes, not numbers. Let that sink in.

So what do they do? They point the intake out of the engine bay to artificially reduce intake air temps(“IATs”). Sorry to break it for you — this doesn’t mimic actual road driving even remotely. I actually see IATs dramatically increase in “normal” driving conditions — as high as 40-60 degrees over ambient with these style intakes.

So let’s use the tool at our disposal — the dyno — to get empirical data on how the engine is affected by changing the position of this style SRI.

The Test

The car in question is a 2013 Civic Si w/ said SRI, catted Full Race DP, RBC swap and stock exhaust. The change over a completely stock car looks like so. Overall not a bad gain, and as always, the RBC sacrifices mid range over the stock intake manifold.

Now that we have done the “tuning” to extract power, let’s see how intake placement affects power. We turn the SRI back into the engine — but leave the hood open, and do a subsequent pull (making sure engine conditions are at steady state — meaning we don’t have a heat soaked car with a high ECT, we make sure we start at the same temps as a high ECT will cost power as well and render our test meaningless). The chart to the left demonstrates this change — all we did was lay the intake back in the engine bay — and we lost on average 10-12whp and 10-14wtq! Really?? What???? WHY IS THIS??

But it gets better, what happens we if shut the hood? Whoops — looks like we lost another 5-8whp and 5-6wtq just shutting the hood over our previous pull. The left chart demonstrates how much we lost overall — as much as 20whp! No way, right? Yes way!

Why Does This Happen?

This is actually quite simple — when you tune a car, particularly on the dyno, you are tuning in as close to steady state conditions as possible. You do this so when you make changes in the ECU (“Tune”) you can verify your changes have some sort of impact on the way the motor runs. Whether this is good or bad. You also have to make conscious decisions on how you want to leave the motor running long term — these should be intelligent decisions as they will dictate not only long term reliability but how well the motor runs in dynamic conditions which the ECU does have to account for.

So why the power loss? Quite simply, Intake Air Temps went up and the motor got warmer air as conditions changed. The read outs to the right indicate what the intake air temp (IAT) was on each pull. As the IAT went up, we had a respective drop in power. Will this drop in power continue to get worse as IAT climbs further? Absolutely.

In fact, as IAT climbs, the motor will run hotter and less “stable” (to put it in simple terms), which will create situations in which the motor can “knock” or “detonate” — which is an unsafe condition where your combustion event is no longer in a safe and controlled burn and will destroy your motor if left running in this state. The ECU allows us to account for this behavior — by reducing time and/or adding fuel. An example of this is in the table to the left. Does reducing timing hurt power? Absolutely. Is it necessary? When the motor could potentially see unsafe running conditions — absolutely. You want to protect the motor as much as you want to make power.

Tuning Tool

Now back to those dyno “numbers”. A dyno, any dyno, is a tool. You can take your car to 15 dynos and get 15 completely different “numbers”. You can always “make more power” when you stick a car on the dyno and make changes in steady state conditions — especially if you disable any of the dynamic compensations the ECU will apply to protect the motor. Factor in strap down variances (particularly on roller style dynos) and your numbers will potentially be all over the place from day to day, dyno to dyno, etc.

I use the dyno as the tool it was meant to be. Making power is awesome — fun even, but at the root of it, the correct PARTS will make power, and will potentially make better power in fluid day to day conditions as well. The tools at my disposal will let me find where the motor runs best, runs safest, and how it responds to the changes I make. Tests like finding out what AFR the motor runs best at — and what AFR it actually starts to lose power (from either running too hot, or “choking” on the fuel). Yes the plot to the right is an N/A 9th gen, the AFR it loves to run at might surprise you — it definitely isn’t 13.88.

In Conclusion

It’s easy to hit the plus key on your keyboard and keep on pumping timing into the motor to “make power”. It’s all fun and gains til it melts a piston or throws a rod and the oil pump “failing” gets blamed for the motor going out. We’ll be having none of that here — a lot more to tuning than “making power”, sorry.

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Old 08-27-2016, 08:34 PM
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I think it mainly re-arranges the powerband...

Like I perfer my vehicles to pull well from a stop, but pull hardest at the top end...

As in, the faster the engine spins, the faster I go... Like, as the engine's volume increases, the farther into the seat I am...

Sadly, unlike every other vehicle I've been in, the RDX doesn't do that... It just pulls hard at 4,500 RPM, and it just pulls flat and steady from there.... It makes the car feel slow, I don't know why, but I hope and pray the intake makes it feel more natural to me...

I've read from several scoures, an intake helps the RDX in that department, and Vtec will be louder... I'm also getting a reflash, and maybe a mid-muffler delete...
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Old 08-28-2016, 12:32 PM
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Looks like I may return my intake back to stock. Threw me off as I thought that the SRI for the RDX leans out the A/F and increases power. I'm conflicted by this these different info. Although tuners know best.
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Old 08-28-2016, 07:11 PM
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at least the cpe doesn't place it towards the back
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Old 08-28-2016, 09:35 PM
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The CPE also doesn't have a heatshield. I like that the stock has that snorkel that goes down. Also the tubing/arms aren't metal increasing the IAT. I will miss the sound though.
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Old 08-29-2016, 01:10 PM
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Originally Posted by CrAzYNeSs View Post
The CPE also doesn't have a heatshield. I like that the stock has that snorkel that goes down. Also the tubing/arms aren't metal increasing the IAT. I will miss the sound though.

call me first pm me your number.
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Old 08-29-2016, 02:20 PM
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1. There was an article in 2007 or 08 in Turbo magazine. They have tested different bolt-ons on RDX, And SRI showed the drop in power on the low end and slight gain (4-6 hp) on the top end of RPMs.
Its been scientifically proven that an average person would not feel any difference in case of an increase in 6-8 hp gain in a modern car.
2. Regarding Tubing-arms not being made of metal and increase in IAT. Correct me if I am wrong but I was under impression metal actually gets hotter faster than plastic and thus IAT raises faster too with SRI in place.
3. The OEM snorkel though goes down and then UP to the radiator where it is attached to the frame. It collects hot air from the radiator surprisingly fast on a hot day and staying in traffic.
3. IMO, the best intake mode till now was posted in one of the threads here about 4 years ago (with screenshots). The idea was to remove the original snorkel and replace it with a flex plastic pipe. Then direct the open side of pipe to a whole between the bumper and the right fender. That allows to take air with lower temperature. I did it on my RDX. Do I feel any difference while my RDX keeps moving? Probably not. But if I got stuck in traffic it def makes a difference when you start to move. There is less delay and lag.
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Old 09-27-2016, 11:16 AM
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Thanks for the good info wrench and proto, just bought an 09 base and looking to do some mods and trying to figure out what are the best mods for the buck, this definitely helps prioritize.
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Old 09-29-2016, 12:20 AM
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A CP-E intake actually has a MAF housing that is shaped to allow more air past the sensor. That tells the computer that less air is entering the car than actual is. Of course the short term trim compensates for that. So you'll end up with a vehicle that's louder and runs a bit rougher. It's actually probably the best way to go if you want horsepower and only ever want to spend $300 on an intake that adds some noise and a little power at the cost of some extra roughness. This is the most important thing about the CP-E intake: If you go any further, you will be replacing it. It does not have a big enough MAF housing for upgrading a bigger turbo or the like.

I wonder often how much butt dynos are really about volume. In any case, listen to Wrench and Vit. Making sure that the sensor gets a good reading is really important in these electronically controlled cars. That's what the computer uses to adjust how much fuel goes in.

The best performance per dollar mods, I think, are: a Flashpro unit with a tune for 93 octane, and steel brake lines. You'll get noticeable improvement in dynamics for $1000, and not just that, neither of those will be wasted.

The main limitation overall is the lack of the ability of the stock turbo to flow air to support more than 270 or so horsepower at the crank. That's why those who are seeing 300wheel + are doing so on either swapped or upgraded turbos.

TLDR: If you only ever want to get only 1 thing ever, get the CP-E intake. If you want to do anything else at all, ever, start with Flashpro.
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Old 10-24-2016, 09:18 AM
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Still confused on this on. Does the CPE decrease torque/power at the low end. I hardly drive my RDX in sport mode and go over 4K RPM's before shifting. So with that said, I am looking for the quickest response when I press the gas at the start. Not racing, but just driving. Just wondering if I should go back to stock and get a tune instead. What are some opinions out there on the CPE versus stock on daily driving? Thanks
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Old 10-24-2016, 09:55 AM
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Funny enough, I had a custom tune on mine via the Flash Pro, and when I decided to go back to stock and sell the unit, I noticed both an increase in throttle response in normal driving as well as an increase of about 2 mpg. Over the last 5000 miles since I went back to stock I have averaged an indicated 24.5 mpg (closer to 23.5 actual, but still way better than anything I've done before). Now that summer is winding down and I don't have the a/c on 100% of the time, I'm seeing another uptick in mileage. My last tank was 25.5 indicated...on a car with over 100k miles that is only rated 24 highway. I'll take it.
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Old 11-23-2016, 09:13 AM
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Wrench116-- I was reading a different post on intakes and someone mentioned a person by name instead of profile name but i believe they were talking about you. If so, are you still making custom intakes/extentions that run below the bumper instead of the CPE that stops behind the battery.
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