I have a 2004 Rx-8 Premium with a manual transmission, and I was thinking about getting a cold air intake. Are cold air intakes beneficial for a rotary engine? If so, what kind of intake should I look at and how much should I expect to spend? And what is a good brand? I have to level with all of you, I am new to the sports car world and still have a lot to learn. Any advice on this intake would be great.

 

Nothing out there shows any gains worth the $$$. Browse the Aftermarket Performance section for more on CAI. Some people like the sound of it, which is cool, but for HP gains, you won't see much at all.

 

Try Racing Beat.

S

RB Site

 

RB and AEM seems to be the top choices.

for HP gains, you'll be lucky to get -/+ 1-2 hp.

nothing more than cosmetics and sound on our cars.

 

the reason why the gains are low is because your car stock already sucks air from the front bumper, instead of hot engine bay air, so it's already a CAI.

 

sweet, thanks, you just saved me 400$. i believe injen makes some too! but ater hearing that, i may not get one.

 

the revi air duct is $130 and instead of just sucking air from the front bumper, brings air in from outside of the car.

 

it doesn't matter where it sucks from as long as the air is cold...

car manufacturers today have realized that cold air intake is better and as such most cars today come with them stock, they're just not pretty.

some ppl believe that a cold air ram is another matter though and you might see 2-3hp increase with one that way. but you'll only see the extra power at 70 mph, and there's no point having extra power at that speed unless you're doing nascar tracks

 

i do agree with those posted above but 2-3hp is 2-3 more hp then you had

 

The Mazdaspeed CAI is apparently a rebranded AEM CAI, so you could get that. All the benefits of a popular CAI brand plus a Mazda-backed warrantly if you have a dealership install it...

 

the dealer will quote some outrageous pride like 800 dollars to install it, they did that to me. I literally dropped my jaw and said, excuse me???? No thank you....

 

The Racing Beat with ram air duct or the AEM/Mazda speed CAI (which are about the same) are the ones to get.

The Racing beat one ( http://racingbeat.com/ConRX8.htm ) appears to have been extensively tested. Even without the ram air duct, they were saying up to 5+HP above 7,000 RPM. I would expect the ram air duct to add a little more to that. People who did the switch, have said they have seen improvements in their 0-60 and 1/4 mile times.

It appears the sucess of the AEM/Mazdaspeed CAI is because of its postion. Its getting air from the front of the car and its pipe appears to help insulate the air from the engine, so its getting 5+ HP increases too.

Something, that is like in the middle would be the odula ram air intake. https://www.rx8club.com/australia-new-zealand-forum-37/taka%92s-review-odula-ram-intake-duct-58857/ . The Odula can hook up to the stock air intake box. Odula has 2 ram air intakes. That link only shows one of them. Might be a choice if you want to change the air intake and go with a different air filter or some odd combination. The link also shows the stock RX-8 intake.

Interestingly, in Japan, a pro tuner called R-Magic has an replacement air filter for the RX-8 and RX-7 that they are claiming will give you 5+ HP too. I've not seen anybody test it and confirm the HP gains, but I heard they are selling like crazy. Its supposed to cost around $100 dollars. Expensive, but cheaper than CAI, if it can really give those type of HP gains. It seems that the air filter material, might be able to make a difference too. Since the right material can improve air flow, but still be just as effective at filtering dirt.

My understanding is that the RX-8 VFAD was well designed, so there is not much you can do to improve overall HP, but there are a couple of tricks. Get air from the front or change the type of filter that you are using, seems to be the 2 major things.

Link with lots of different intakes - https://www.rx8club.com/series-i-aftermarket-performance-modifications-23/intake-intakes-intakes-90202/

 

So how about the K&N drop in air filter. They are about $45, but is it worth is?
I know , just a little off the subject, but is it $45 well spent or not.

 

I wouldn't put a K&N air filter on my lawnmower, much less my car, any car.

Pilgrim

 

K&N has an intake that they claim adds 10HP @ 8700 RPM.
http://www.knfilters.com/search/prod...d=69-6030-1TFK

Amazon has it for $251.00 - $279 (they also have a $20 coupon deal going if you spend $99 or more) plus free shipping.

http://www.amazon.com/K-69-6030-1TFK...8&s=automotive

 

If you want 1-3hp, a polished metal pipe, and lots of noise, AEM or Mazdaspeed.

If you want 1-3hp, stock look, barely any more noise than stock, Racing Beat w/ duct.


There are no other reasonable choices. No one else makes a PROPER intake with screens and such.

The K&N filter? Do you like rough idling and stalling? Yeah, neither do I.



As said above, flow mods won't do very much on the 8. As on any catalytic convertor-equipped car, replacing the exhaust WILL show a good gain, but again, probably not noticeable.

Your car will SEEM faster, because with all the cool noise you have going now, you will be DRIVING faster to hear this noise more.


I say skip the middle-ground, and go turbo. A good used kit + interceptor-X can be had for around 3000 or less...why spend almost that on intake and exhaust?

 

Adrock, I'd like to know how you know exactly how much HP gains the RB air duct makes, since you can't dyno it at 90 mph.



PS: My CAI is going to cost me about $60 to make.

 

What about the REVi with Ram and if you get your PCM flashed by RB will that make a bigger difference?

 

I have had K&N's in many vehicles and they have performed well in all of them - the key is to NOT over-oil them.

If you do over oil, they can bleed oil onto you MAF, which can cause poor readings that can lead to rough idling, etc.

Still, it's good practice to clean your MAF occasionally anyways as they will get dirty over time no matter what kind of filter you use.

 

Waste of money.