so which one gives the best gains!?

The way Mazda designed the stock intake has been hard to improve upon. Upgrading the drop in filter is really the cheapest and easiest way to go.

If you really want a Cold air system I would only suggest going with the AEM. It really is the only one to not show loss in power or show possible small gains.

lots of info on this is you search around the forum

The best you can hope for is 2 to 3 HP at 7500 RPM from either the AEM or the Racing Beat. Unless you are tracking your car and live up there in the high band, neither is really worth the money.

Sound is a different story. The AEM gives the car a cool throaty sound. The RB sounds good too, albeit quieter. If intake noise is worth the money to you, go for it. But, be aware that some AEM owners have had problems with water ingestion.

You can install a K&N panel filter for about 1 HP gain at high RPMs at the cost of substandard filtration if you like.

[All of the HP gains listed above are hard to prove since they are within the margin of error of the test dynos.]

All other aftermarket intakes will cause rough idle problems and/or loss of HP.

I am currently running the Racing Beat Duct with the Stock Airbox. I did some searching but could not find if anyone tried replacing the K&N Filter inside the RB Revi Intake with a AEM Dryflow filter. Has anyone had success with this?

I am getting very high Intake Temperatures and was thinking that they might be lower with the AEM/MS or full RB intake. However, I do not want a K&N filter which would reduce my options to Stock or AEM/MS.

Thank you.

Just recently bought a AFE performance CAI kit. It was a simple bolt on application so far loving the induction sound of it.

AEM Intake
 

In response to my above complaint. The RB Air Damn had nothing to do with the heat issues I was/am experiencing. However, I ended up purchasing an AEM intake. My car has been tuned by MM and was pulling 228 maf/g in 2nd gear. With the AEM intake, I am pulling 254-260 maf/g in 2nd gear. The car does 'feel' more responsive and the sound is not any louder than the stock. (I have the Black Halo Midpipe and Mazdaspeed Exhaust)

You can't compare MAF flow untuned to MAF flow after being tuned.

I should have been more clear. The car was tuned with the stock intake and RB Duct. It was tuned by MM and was pulling 228 maf/g. The ONLY thing I changed was the intake. Now it's pulling 254-260 in 2nd gear. (With AEM) Though I should mention, I did modify the intake to match Eric Meyer's suggestion. (Chopping off at the last elbow)

I was surprised by the results.

my car has been acting up. i've gotten some low compression readings, some misfires and some o2 sensor codes and some no start when hot issues some loss of power on the highway and stalling issues yadda yadda.....


N E WAYYYYY


I realized i hadnt cleaned the air filter/box and MAF etc for awhile and figured i'd better get to it. so of course the intake tube has some oil in it, the maf is dirty, the filter IS FILTHY all as expected.


what i did not expect ( but due to some loud noise from the intake a time or two should have) was to hear a rattle from inside the REVI Filter when i pulled it out.

the intake bell on the inside of the filter was loose and flopping around in there. the clamp must have gotten loose enough for the thing to slip out . i imagine that can cause a few breathing problems at speed...

:wallbash::spank::pfanndina:slap:

So one question and it may be stupid but whatever right. Here goes. I have a gutted cat and a cold air intake. There was a cheap filter on it when i bought the car. Now i am wondering if its causing my slight roughness in idol. So i found a big ol k&n filter. Is bigger better?

https://cimg1.ibsrv.net/gimg/www.rx8...ea20efa753.png
Its the one on the far left. The big oval one

Good filtering is better. Not a big fan of K&N filters because when the oil is flooded with @$#@#$, the filter allows even more @#$@#$#@$ though to your engine. Too much open area of large size. Paper filters work great and replacing them is low cost. I've seen too many dual sport motorcycles (piston mind you) fail early due to shitty K&N fiulters allowing too much bypass of dirt. K&N claims more hp, so if you want 2 more hp but way more dirt so be it.

You are kind of stuck, because you already have a CAI. Adding a good filter can't hurt, assuming it is a decent CAI to begin with. (The only good CAIs for the 8 are made by AEM and Racing Beat). I am not a fan of any of the oiled filters. They may flow slightly more air, but they also flow more debris. And oil.

The thing is, the car came with a good CAI. When the car is moving, the air intake temps are within 2 degrees of ambient, according to my measurements. The reputable aftermarket CAIs claim HP increases of up to 3 HP at 7,500 RPM, which is within the margin of error of all dynos. You have to ask yourself if (maybe) up to 3 HP at an RPM at which you drive 0.5% of the time on the street is worth the trade-offs of an aftermarket system. It certainly is not to me, and I track my car about 15 times per year at an average RPM of 7,200.

im just thinking cooler and more air flow with a bigger filter. I know it wont give more hp but imo its better for engine in general.

What's actually better for the engine in general is not to have a filter that's not doing it's job properly. K&N's are known to not do a good filtration job on the RX-8.

Try cleaning your MAF first and see if that fixes it.

I get some rough idle for a couple seconds here an there quite often, even with a clean Maf. I'm obviously extensively modified but I think it is just the nature of the beast sometimes with this engine.

Your idle issue is probably due to the new CAI causing the intake air to flow with more turbulence over the MAF sensor.

Try one of these to smooth out your idle:
Honeycomb for MAF

Should be installed about 3-5in forward of the MAF sensor. You can use a mesh screen instead, but from my experience the honeycomb air straightener gives better results.

The cai was on it when i bought the car. And the honecomb was there aswell. Im still stuck on the cheap filter that previous owner put on. Should i get the big k&n filter? Seems to be the best brand avail here

I highly doubt you already have the honey comb,
https://ep.yimg.com/ca/I/yhst-615924...54_2266_346033

you probably just have the regular screen.
http://www.swankmonkey.com/mazda/rx8...f/IMGP1697.JPG

As for the filter if you can get an AEM dry flow filter that would be better

https://cimg1.ibsrv.net/gimg/www.rx8...d7f515970.jpeg
And no i guess i dont have the honeycomb. Just the screen

just a fair warning for Racing Beat REVi intake owners …

I bought an RX8 that suddenly lost an engine with the prior owner (only runs poorly on one rotor). It had some aftermarket parts on it, one of which was a Racing Beat REVi intake box assembly. Upon disassembling the intake and removing the filter; which the round filter itself inside the box is actually open on both ends, but Racing Beat supplies a metal cap and hose clamp to seal off the forward end toward the inlet opening, I found the metal cap lying in the bottom of the intake box and the hose clamp was not tight.

There’s not really any way to know for sure if this was the cause of the engine failing, but it didn’t help. The metal filter cap is showing scratch marks that suggest it had been sliding around in the intake box for a while and the filter interior was also quite dirty. Because without the filter end cap in place then unfiltered air along with rocks, sand, leaves, bugs, etc. is going straight through the forward open end of the filter and directly into the engine (see red arrow below pointing to the blue filter end cap).

https://cimg9.ibsrv.net/gimg/www.rx8...d9c27016d.jpeg


So whether buying a brand new REVi intake from Racing Beat, disassembling it to clean the filter, etc. you *always* need to make sure the metal filter cap is securely help in place on the filter by fully tightening the hose clamp for it!
.