Do intake systems really make a difference?
 

Serious question from someone who is new to the world of tuning. I've been lurking on this forum for quite a while before signing up, and I've lurked on Ford forums, Nissan forums, and a bunch of others to try to get some unbiased opinions.

So, to keep things short... this is what a lot of people are saying about cold air intakes:

- Possible gains in power in higher RPMs
- Possible loss in power in lower RPMs
- Possible overall loss of power http://www.youtube.com/watch?v=gCi2yo4UqPI"]http://www.youtube.com/watch?v=gCi2yo4UqPI

Several of my friends in the rallying world have been racing for many years, have $40k+ cars and put in $60k+ of mods in their cars (some went turbo, some supercharged; some went as far as engine swaps, some rebuilt an AE86 from scratch) and have pretty good track records and sponsorships. They tell me:

- Don't bother with intake systems
- "Faster throttle response" from these systems is purely psychological
- Even exhausts won't do much
- Prepare to mess with headers, ECU, and a bunch of other stuff to notice a difference
- Ditch my paddle shifter, get a manual, and slap on turbo or supercharger if I want to see a noticeable difference
- Don't go cheap

So all in all...

Is it worth $300, $400 to get a 5hp boost at 6000rpm, if that boost even exists?

Websites that explain the theoretical benefits of CAI and ram intakes are websites that sell or develop these products...so I take all of those with a grain of salt. Theory is great... but if these products did have quantifiable benefits, I'd think that there wouldn't be so many people against it. So consider me on the fence for now...someone convince me otherwise.

They make a difference on poorly designed OEM intakes and when moving A LOT of air (compared to stock)... neither of which is the case for most buyers, especially for this platform right now. Many like the sound an intake creates; I find it kind of obnoxious. That's about all there is to say about that. So no, it's not worth the money considering only a tune will extract the most from your $300-400 purchase, while still losing some low end grunt.

Hi from Rockville!

I dunno Orbital. I've seen the Injen and the Accelerated Performance Dyno charts and , yes , they show gains at the peak for HP and TQ but loss everywhere else, especially on the low end. But one intake I've been quite impressed with is the Takeda intake. Their dyno's showed overall gains across the board, from the low end to the mid to the high end. Neither torque nor horsepower were lost on the Takeda's dyno. This surprised me quite a lot and it has me waiting on possibly ordering on depending on if everything goes well with Accelerated Performance's turbo kit. (Don't wanna be buying an air intake if it's gonna get replaced)

Oh? I saw some members trash-talk Takeda for delaying their Dyno results. Also, skoodge, could you show me how to interpret the Dyno results?

If an intake system can give me proven increased performance across the whole band, then I'm in. My auto FRS gets an average 31.8 mpg so I don't care about getting 32 mpg if it means that I'm driving with reduced power in the low end.

Also,

What's this I'm hearing about the auto transmission's inability to cope with a turbo kit? My racer friends are telling me I'll destroy my auto transmission with turbo, and that I should have gotten a manual if I really wanted it.

Any sort of forced induction (or other large power increase) will put extra strain on a gearbox not originally designed for that power level and stock auto gearboxes are a fair bit weaker than manuals in handling the extra power.

It may not lunch the gearbox, but it will shorten its life a bit

For what it's worth, takeda's dyno numbers were pulled in 3rd gear... 3 weeks (and who knows how many miles) after their baseline pull. Until they show back to back pulls, stock to mod, with the same increases, I am going to doubt their claims.

Also, when comparing power numbers, make sure gear ratios (4th to 4th for example) match and the dyno data looks legit.

Hmm yes, I see their Dyno chart, that's like a good 2 weeks between runs in third gear. I'd like to see a back-to-back run. Although the way they handled their Dyno... not sure, but they lost a bit of credibility for me.

I might just grab some springs, lower the car and call it a day.

BTW How does the Airaid compare?

http://www.ft86club.com/forums/showp...&postcount=102

I love the design of the air box, but not personally a fan of the rotomolded tubing. Some people love it, but I prefer shiny tubes. :)

Can't speak for sound or 'feel', though.

AIRAID seems like a highly reputable company, however, so I would place as much trust in them as in Injen.

Vehicle engineers have many factors other than maximum performance to consider when they design OEM intake systems (noise level, fuel economy, emissions, etc.) and in the process leave plenty of room for improvement. Aftermarket air intake systems replace the factory air box and tubing with more efficient components designed to create more power. The two big things that aftermarket air intakes systems strive to do are:

1) Draw in larger amounts of cool dense air from outside the hot engine compartment. The more air your engine can suck in and push out the more power it will make.

2) Reduce the restriction in the intake system by increasing the diameter of the tubing, smoothing out the interior of the intake, eliminating baffles and muffling devices, and limiting the number and severity of any bends in the tubing.

Aftermarket air intake manufacturers address these tasks in many different ways with some being more successful than others. Poorly designed systems can actually cause your engine to make less power, while a quality system can add 10-20 rear wheel horsepower in larger displacement applications. In your search you will no doubt come across advertisements that mention outlandish horsepower gains, this should be an instant red flag.

It is important to keep your expectations realistic when considering an intake on its own though. The intake is just one component of a very large system. On its own there is only so much that can be gained if supporting components which limit the effectiveness of the intake are not also addressed. Only as those other components are upgraded will the full benefit of an upgraded intake be realized.

The worse the stock system is, the more you can gain. Pretty simple. The stock frs system is pretty clean and takes its air from ahead of the radiator. I don't see gains being huge, but Perrin is also claiming some pretty big gains. I don't know if that reduces their credibility or makes me question the stock system, but there it is.

On my old 01 Subaru Outback (same engine as Impreza 2.5) the stock intake was very restrictive. I bought a cheap ebay intake that was just a curved tube with a cone filter on the end and it made a noticeable increase in power especially at higher rpm. But it roared and droned so much, I got rid of it. I also noted the filter was very poor. Ultimately I preferred a little less power for more peace and quiet.

Depends on the gearbox. Subaru's 4EAT could hold ~350-400wtq before it popped. When it did pop though, there was no replacing clutch packs or anything because the tranny case actually split. Typically though, automatic gearboxes have been maligned as being weaker. Ultimately, their killer is heat; a properly sized transmission cooler in front of the radiator and condenser assemblies will allow for that extra cooling requisite in performance settings. It will alleviate symptoms, but ultimately too much power = death until you get upgraded shift kits, valve bodies, torque converters, etc..

So is the auto tranny up to the task of a small turbo and tranny cooler?

The auto from a 7th gen Celica GTS can hold tons of power. The manual starts to break above 250 tq. The auto has held as much as 600 tq with many hard launches down a drag strip.