Aftermarket Intakes for Modern Cars
Aftermarket Intakes for Modern Cars
(OP)
Hello to people who are TANGIBLY USEFUL to society! I have great admiration for engineers and in my next life will be one:)
I have a question to which I am not able to find an answer, and I have been searching for several years now, and actually have run out of words and key-phrases to input into a search engine. I hope someone could give me a comprehensive answer, or maybe point to a mildly technical articles (no books, my caliber is too small) that would point a way to my general comprehension of the subject.
Here it is: DO AFTERMARKET INTAKES ADD POWER TO A MODERN (2014+) CARS? Like from a more or less "reputable" aftermarket company for a 4 or 6 cylinder NA engine car from a major automaker: Chevrolet, Mazda, Toyota, etc.
As you can imagine the forums with blissfully ignorant are full of all sorts of rants, which to me resemble religious sects arguing who's "truth" is closest to god. The skeptic in me leans heavy towards "no they don't add any power", but I am really open-minded. I appreciate your time you took to post your opinions.
I have a question to which I am not able to find an answer, and I have been searching for several years now, and actually have run out of words and key-phrases to input into a search engine. I hope someone could give me a comprehensive answer, or maybe point to a mildly technical articles (no books, my caliber is too small) that would point a way to my general comprehension of the subject.
Here it is: DO AFTERMARKET INTAKES ADD POWER TO A MODERN (2014+) CARS? Like from a more or less "reputable" aftermarket company for a 4 or 6 cylinder NA engine car from a major automaker: Chevrolet, Mazda, Toyota, etc.
As you can imagine the forums with blissfully ignorant are full of all sorts of rants, which to me resemble religious sects arguing who's "truth" is closest to god. The skeptic in me leans heavy towards "no they don't add any power", but I am really open-minded. I appreciate your time you took to post your opinions.





RE: Aftermarket Intakes for Modern Cars
Ditto air filters. The pressure drop across a standard air filter is essentially zero.
The reason for this is that hp is one of the few hard numbers manufacturers can boast about so they spend a bit of time on it.
The exception is tuned runners on the intake. They could usefully modify the torque curve.
The other gotcha is heat pickup in the intake, it would be a good idea to get your intake air to the plenum without warming it up too much.
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: Aftermarket Intakes for Modern Cars
What would be a counterargument to the claim that OEM intake is also tuned for relative quietness, and therefore its restrictive, and therefore an aftermarket intake - which is louder - is less restrictive, so it adds 3-10 horsepower. It sounds intuitive, but I know there is a high chance for a catch here. I've red somewhere that "..... if you know the internal laminar flow cross section, the intake will not be affected by that. IOW, as long as the laminar flow section of flow is wide enough to handle the mass flow, it is all good, ugliness not withstanding...." Would this be an answer?
Thank You
RE: Aftermarket Intakes for Modern Cars
Probably the most practical way to get the maximum available power out of modern engines is to feed them the highest octane fuel you can get from your local filling stations.
Other than that, for any significant power gains, these application specific options come to mind:
Other than the above, you might as well just buy the vehicle that already comes with the performance you want, or else roll up your sleeves and start learning about hot rodding from the ground up.
"Schiefgehen will, was schiefgehen kann" - das Murphygesetz
RE: Aftermarket Intakes for Modern Cars
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: Aftermarket Intakes for Modern Cars
RE: Aftermarket Intakes for Modern Cars
As with many questions such as this, the only real answer is "It depends." You may gain power on certain applications. You may not gain any power on other applications. You could also lose power on certain applications. By application, I mean a certain aftermarket intake applied to a certain vehicle.
RE: Aftermarket Intakes for Modern Cars
Would aftermarket "louder" axel-back exhaust qualify for "reduced exhaust restriction"? Let's take 2014 Mazda 6 with a 2.5L NA engine as an example.?
@Greg
No, I don't think it causes any restriction - I do not have an aftermarket intake on my car, as I don't think an aftermarket one is any better than the OEM. But many people on plebeian forums make all sorts of claims for these aftermarket intakes (short-ram and col-air) and come up with all sorts of sophisticated-appearing theories of why they add 5-10HP and improve fuel economy. That's why, not being an engineer, I decided to ask real engineers to give their answers. I mean, it's easy to find information from real scientists that vitamin supplements are duds, but NOWHERE can I find an engineer's view on these magic devises - aftermarket air intakes - that add power and fuel economy.
@tbuelna
the claims such as that an OEM air intakes are designed to satisfy multiple parameters (NVH, fuel economy, etc.), is what people claiming 5-10hp gains from simple $189.95 SRM or ColdAir aftermarket intakes use to support their claims. An aftermarket intake is nosier, and therefore more free-flowing than OEM, and therefore produces gains. As I've written earlier, I understand that automotive engineers are not idiots, but I don't know a proper rebuttal to such positions
RE: Aftermarket Intakes for Modern Cars
- Steve
RE: Aftermarket Intakes for Modern Cars
I understand:) But when OEM muffler is twice larger in diameter than an aftermarket (I'm talking about axel-backs only here) the claims that they are more free flowing seems logical, at least on the surface. Could you please tell me why it isn't so? Thank You
RE: Aftermarket Intakes for Modern Cars
RE: Aftermarket Intakes for Modern Cars
If the aftermarket muffler is physically smaller, it's going to be much louder. The physical size is not a sufficient predictor whether it will be less restrictive.
And just because the muffler is "less restrictive" doesn't automatically mean that the engine connected to it will make more power, either.
RE: Aftermarket Intakes for Modern Cars
The press don't normally get to snap dev vehicles wearing their infinite exhaust & intake.
http://www.moto-choice.com/en/Press-Releases/673/t...
- Steve
RE: Aftermarket Intakes for Modern Cars
Assuming the factory system has sigificant restriction (several psi at WOT/max rpm), to get a worthwhile reduction you probably need to gut it and start from the exhaust manifolds with a completely new system. The catalysts are probably the biggest net bottleneck, and it isn't cheap, and probably not legal to replace them with anything significantly less restrictive. And of course removing them completely is certainly not legal, and probably will cause the control system to go into limp mode due to the incorrect O2 sensor signals that will result.
The long and the short of it is, while hot rodding is great fun, its much simpler, easier, and more fruitful with older vehicles. Newer vehicles just present a lot of difficult obstacles. Not insurmountable ones, necessarily, but it's best to start the learning curve with older vehicles, unless you want to pay a pro big bucks to do it for you. And I haven't checked, but I suspect the late model applications with available legal and significant aftermarket performance upgrades are few and far between.
"Schiefgehen will, was schiefgehen kann" - das Murphygesetz
RE: Aftermarket Intakes for Modern Cars
I think where the aftermarket can show best is with manifolds for modified engines.
RE: Aftermarket Intakes for Modern Cars
RE: Aftermarket Intakes for Modern Cars
First of all, an OEM would not put an engine cold air intake system into production that cost anywhere close to $189.95. The typical cold air intake system on a production auto engine likely costs less than 1/10 of that amount. As to your question of how to rebut the argument that aftermarket engine air intake systems are technically superior to OEM systems, simply ask for an explanation of what the aftermarket product designers know that the OEM product designers don't know. The OEMs like GM, Ford, Toyota, BMW, etc, each have engine design depts. with hundreds of engineers and analysts and budgets of tens of $millions. Do you seriously believe an aftermarket company with maybe 1 or 2 engineers, a tiny fraction of the budget the OEM has, and far less access to testing resources, can do a better job of designing/developing an intake air system?
RE: Aftermarket Intakes for Modern Cars
Dan - Owner
http://www.Hi-TecDesigns.com
RE: Aftermarket Intakes for Modern Cars
After the air and exhaust replacements! the fuel pump, injectors and other items are at their top end and need replacing. Changing injectors means ecu reprogramming so with that addition you can see a 25% maybe 30% increase. Next, it's stronger cranks, rods and pistons and a big checkbook.
RE: Aftermarket Intakes for Modern Cars
RE: Aftermarket Intakes for Modern Cars
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RE: Aftermarket Intakes for Modern Cars
Though hamstrung by price and other performance parameters, the difference in expertise and resources brought to bear on the target between OEM and aftermarket is colossal.
My stance on this is that if you want to improve almost any performance parameter of a modern car you need 1 of 2 advantages over the OEM engineers:
1) Be willing to spend *way* more money than them, taking into account that their part also had all the economies of scale under the sun to help them.
2) Be willing to reaaaaaaaaaaaally sacrifice 95% of other performance parameters (fuel efficiency, noise, safety, comfort, legality, etc) to maximise the one you are interested in.
Throw extremely advanced, impractical, and cost prohibitive materials and processes at it, and ruin everything else about it, and yes, you too can have ridiculous peak power figures.
RE: Aftermarket Intakes for Modern Cars
I have seen a number of back-to-back wheel dyno tests on C5 and C6 Corvettes.
A cat-back exhaust can show around a 5hp to 15hp improvement.
A cold air intake can show around a 5hp-10hp improvement. There is one cold-air intake that is track proven by multiple owners to gain around 3/10ths in the quarter mile on C5 Corvettes.
Changing an LS1 from the first design LS1 intake manifold to the newer design LS1/LS6 intake manifold gives a solid 5hp improvement.
Headers with cat converters that will pass a tailpipe emission sniffer can show about a 25-50hp improvement. Headers do require tuning as well.
If you want to go even more extreme, there are supercharger kits that can be added. You can boost the engine by around 100-200rwhp and the car will still drive well and still get good gas mileage off the throttle. Of course this requires improvements to the fuel system and tuning as well.
All of these improvements give a solid power curve that has increased across the whole range of the test, typically around 2000rpm-6000rpm.
My guess would be that percentage wise you might get similar improvements on some smaller engines. So a 180hp 4-cylinder engine might show a 2hp increase with a cold-air intake or a 7hp improvement with a header system for example.
The modern fuel injected engine is fairly immune to intake tract and exhaust system changes (cat-back type systems) affecting the closed loop fuel control system. You would likely have to choke off your air filter badly enough to have driveability issues before you'd see a loss in fuel economy. Most claims that a more free flowing intake allows for less fuel usage are bunk.
RE: Aftermarket Intakes for Modern Cars
Eh? I thought that "any higher than required gives no further benefit" was the right answer? (so in most cases the lowest octane is adequate)
RE: Aftermarket Intakes for Modern Cars
Was power sacrificed down low to get more upper power? Possibly, but according to the dyno charts any loss was within the confines of statistical error, so it was a fair trade-off (if it even happened).
Dan - Owner
http://www.Hi-TecDesigns.com
RE: Aftermarket Intakes for Modern Cars
"Schiefgehen will, was schiefgehen kann" - das Murphygesetz
RE: Aftermarket Intakes for Modern Cars
The comments about fuel octane and engine power are also correct. A modern stock engine with electronic controls will not produce much more power than when using a fuel with the octane rating it was designed for. On the other hand, it will not likely suffer any damage from using a lower octane fuel than it was designed for, but it will definitely produce less power.
RE: Aftermarket Intakes for Modern Cars
RE: Aftermarket Intakes for Modern Cars
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: Aftermarket Intakes for Modern Cars
I think I'll stick with the cold-air intake that is track proven to show an improvement rather than wasting time measuring the stock intake to "prove" it's the best intake possible.
RE: Aftermarket Intakes for Modern Cars
As for some of the numbers posted earlier in this thread, they do seem questionable. 25-50Hp from legal headers? That's about 10% more power output if you are talking about LS1s, isn't it? Surely it's not losing that much power pushing smoke out the exhaust that you can recover just with some slightly reshaped headers? And surely you won't scavenge your way to 10% more cylinder fill on a reasonable performance engine? I don't know, I know theory but nothing about specific applications, it just sounds unlikely.
RE: Aftermarket Intakes for Modern Cars
You'd also want to measure actual air temperatures in the plenum/runners for both OE and aftermarket to see if any benefit was coming from that. To this point, today's OE composite intakes have to be far better at not adding any heat to the air within than the older metal manifolds (that in most V8s were continually splashed on the under side with hot oil and subject to at least a little exhaust crossover flow).
FWIW, I'm more inclined to believe the claims made by the motorsports branches of the various OE mfrs, which are more or less captive aftermarket entities. Particularly where U.S. 50 state street-legal cold air & re-tuning kits are involved. Sharing a few people from the production engine side is likely.
Norm
RE: Aftermarket Intakes for Modern Cars
LS1 catback gains;
http://forums.corvetteforum.com/1573303063-post11....
http://www.superchevy.com/how-to/73978/
LS3 header gains with no tuning;
http://www.lsxtv.com/tech-stories/exhaust/kooks-ls...
LS1 intake and header gains with tuning;
http://forums.corvetteforum.com/c5-tech/3458784-dy...
RE: Aftermarket Intakes for Modern Cars
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: Aftermarket Intakes for Modern Cars
If people want to think those numbers were all in my mind, so be it, but it's difficult to argue with a 10%+ increase over stock, particularly when it shows at the track.
Dan - Owner
http://www.Hi-TecDesigns.com
RE: Aftermarket Intakes for Modern Cars
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: Aftermarket Intakes for Modern Cars
- Steve
RE: Aftermarket Intakes for Modern Cars
Of course, the dyno did not take into account the reduced weight being carried around, either. The stock airbox being dropped shaved several pounds, the exhaust (Invidia) dropped about 25 pounds, and so on. Adding 25hp+ and dropping 35-40 pounds makes for a peppier car.
Dan - Owner
http://www.Hi-TecDesigns.com
RE: Aftermarket Intakes for Modern Cars
Ford Racing only claims 15 HP for its CAI with the reflash, which requires 91 pump octane fuel vs the 87 that the 4.6L 3-valve engine's "normal" 300 HP state of tune was intended to use.
Norm
RE: Aftermarket Intakes for Modern Cars
Dan - Owner
http://www.Hi-TecDesigns.com
RE: Aftermarket Intakes for Modern Cars
RE: Aftermarket Intakes for Modern Cars
Dan - Owner
http://www.Hi-TecDesigns.com
RE: Aftermarket Intakes for Modern Cars
- Steve