Aftermarket Intakes for Modern Cars 7

[SlavaYkraine]

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.

 

[GregLocock]

Pretty much no. A cold air intake may be of some value, but nine times out of 10 the OEM will have spent a while optimising the pickup location.

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

http://eng-tips.com/market.cfm?

 

[SlavaYkraine]

Gregory, thanks!

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

 

[Lou Scannon]

DO AFTERMARKET INTAKES ADD POWER TO A MODERN (2014+) CARS?

I agree with Greg, probably not any appreciable amount if at all, and certainly not cost-effectively. Tuned runners are a double edge sword (unless variable) - what you gain at one rpm, you tend to lose at another.
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:
[ul]
[li]re-calibrating the performance maps - this requires a considerable knowledge base and depends on aftermarket support (hardware & software) for the particular application; and therefore is best left to experts. This is particularly effective with boosted applications, however.[/li]
[li]reduced exhaust restriction - depending how bad the original system is, there may or may not be worthwhile gains to be realized here[/li]
[li]high power crate motor if there is one that fits your application[/li]
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.
[/ul]

"Schiefgehen will, was schiefgehen kann" - das Murphygesetz

 

[GregLocock]

If you think your intake is costing you power due to restrictions use a water U tube to measure the pressure change along its length. I'll eat my hat if the intake, including filter, of a modern car from a sensible company has a pressure loss of 2 kPA (8 inches of water), which would be a pumping power of say 6000 rpm/60/2*2*10-3*2000=200W, or 1/4 hp, for a 2 litre car at 6000 rpm.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[tbuelna]

It is quite possible that an aftermarket intake manifold can allow a production engine to produce higher peak hp than the factory manifold at certain operating conditions. The reason is that the factory intake manifold is designed to provide the best compromise of many competing requirements like driveability, NVH, emissions, packaging, weight, cost, etc. Factory engine components, such as intake manifolds, are very highly engineered devices. I doubt any aftermarket company has the financial and technical resources available to produce a better overall manifold design.

 

[LionelHutz]

Are you talking "cold-air" intakes or intake manifold. I think you're talking cold-air intakes but you weren't clear.

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.

 

[SlavaYkraine]

@hemi

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

 

[SomptingGuy]

The perceived correlation between radiated sound level and performance has sold many "free flowing" aftermarket exhausts. An exhaust need not be restrictive to do its job, although that's often the easiest way.

- Steve

 

[SlavaYkraine]

@SomptingGuy

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

 

[SlavaYkraine]

correction: I mean OEM muffler is twice longer and wider. I'm not talking about muffler tips, but muffler itself

 

[BrianPetersen]

One of the ways that you make a muffler quiet and non-restrictive at the same time, is to make it big.

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.

 

[SomptingGuy]

"make it big"

The press don't normally get to snap dev vehicles wearing their infinite exhaust & intake.

http://www.moto-choice.com/en/Press...bler-undergoes-emissions-and-noise-tests.html

- Steve

 

[Lou Scannon]

I agree with all the previous comments about exhausts and mufflers.
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

 

[140Airpower]

I think it is always possible to improve on the top end power of an OEM manifold, but probably at the cost of power in other parts of the range. The OEM design is usually highly optimized for the operational parameters the OEM thinks are most important, with a compromised weighting. So the aftermarket piece would probably be inferior overall for normal operation.
I think where the aftermarket can show best is with manifolds for modified engines.

 

[TheBlacksmith]

One of the major tuners associated with one of the big three that has occasionally done a low run of modified cars sold through their dealers is offering a manifold spacer for a turbocharged 4 cylinder. They claim a 5 hp gain on a 252 hp engine for $140 and 45 minute install. Has anyone seen one of these for evaluation, the people that have bought one claim an increase on the "butt" dyno, but no one has strapped on a chassis dyno before and after yet - easy considering the 45 minute install.

 

[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

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?

 

[MacGyverS2000]

I can't imagine a 5hp increase is noticeable on the butt dyno... 10hp is typically the much-cited "minimum", and I would tend to agree with that as a minimum. but who knows, maybe someone out there has a highly-calibrated butt to go with the golden ears others claim they have...

Dan - Owner

http://www.Hi-TecDesigns.com

 

[dcasto]

My experience is that you can get 10% more output with bolt on intakes and cat back exhaust and you are done. Even less than that if the engine is already a high output.

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.

 

[inline6]

most aftermarket tuning companies that try to sell you CAI type kits (not intake manifolds) also sell software and this is probably where the gains come from. its a way of upselling the software for more profits IMO