i have been debating whether I should keep the stock intake, drop in a K&N drop in filter and just get the revi intake duct. Is the revi intake system all that much better than stock? Please can anyone help?

Back when i had my simota cf intake, a buddy of mine in his s2k went at it and he beat me by atleast half a car length

now a month ago, when i took off the aftermarket intake and put back on the stocky, me and the same s2k went at it again and this time i whomped him..

what gives? Are most aftermarket intakes just noise makers and are obsolete compared to stock?

Mazda did a real good job of engineering the Renesis and there are only very small gains to be had from most aftermarket products, unless you turbo/blow.

RB intake is liked here, but not known for adding any real HP, just good sound.

I personally stuck with the K&N insert in the stock intake

sounds like you did the right thing. I was thinking about keeping the stocky and just dropping a K&N filter + racing beat ram air duct

any feedback on that set up?

i have been debating whether I should keep the stock intake, drop in a K&N drop in filter and just get the revi intake duct. Is the revi intake system all that much better than stock? Please can anyone help?

Back when i had my simota cf intake, a buddy of mine in his s2k went at it and he beat me by atleast half a car length

now a month ago, when i took off the aftermarket intake and put back on the stocky, me and the same s2k went at it again and this time i whomped him..

what gives? Are most aftermarket intakes just noise makers and are obsolete compared to stock?

Were there any passengers either time?

I would definately go with the drop in and the duct, since aftermarket intakes are basically the same as stock plus some bling.

The duct cost just as much as an aftermarket intake, so might as well spend your money there, instead of buying that plus the the intake.

Were there any passengers either time?

nope, no passengers. Took off at the same time and everything

I would definately go with the drop in and the duct, since aftermarket intakes are basically the same as stock plus some bling.

The duct cost just as much as an aftermarket intake, so might as well spend your money there, instead of buying that plus the the intake.

im buying a duct from a forum member for a fraction of the price...so duct + drop in filter will add up to a cost less than of a brand new name brand aftermarket intake

sounds like you did the right thing. I was thinking about keeping the stocky and just dropping a K&N filter + racing beat ram air duct

any feedback on that set up?

Won't add any power, but will give you a little ram air effect. Will also add a little intake sound.

Won't add any power, but will give you a little ram air effect. Will also add a little intake sound.

Well you even said it yourself, most intakes dont seem to add any power...so what do i have to lose with a different set-up? Hey you never know might make a slight difference

Hard to beat stock on the '8

http://www.rx8club.com/showthread.php?t=83785

thanks for clearing things up. The thread just seems to clarify that intakes for our cars are just noise makers and make the engine bay look good.

The only 2 things that werent answered for me is

1) with the ram air duct on my car..wouldn't that prevent some air flow getting to the radiator and cause over heating? I have ms front bumper so the openings are alot larger than the stock bumper.

2) Since the Ram Air duct was designed for the revi intake, wouldn't that prevent maximum performance some how with the stock intake? Some people claim that it works just as well with the stocky

Hard to beat stock on the '8

http://www.rx8club.com/showthread.php?t=83785

I remember that thread & also the talk later that the problem was related to LTFT & not the duct .
Anyway I have the RB duct (sealed join to factory intake) + K&N drop in + removal of one mesh screen . The system works well . Cannot say if power is increased but I read around the forum a lot before deciding there was not much to gain by doing anything else.
Someone actually did some 1/4 mile runs that showed the RB was good for 0.1s at most. A couple of others were slower than stock .

Only drawback with the duct is that the filter needs to be taken out fairly regularly (I do it at each oil change) & slapped against something flat to get rid of all the road grit .

1) with the ram air duct on my car..wouldn't that prevent some air flow getting to the radiator and cause over heating? I have ms front bumper so the openings are alot larger than the stock bumper.

2) Since the Ram Air duct was designed for the revi intake, wouldn't that prevent maximum performance some how with the stock intake? Some people claim that it works just as well with the stocky

1/ No - it is clear of radiator air flow
2/ see above

I remember that thread & also the talk later that the problem was related to LTFT & not the duct .
Anyway I have the RB duct (sealed join to factory intake) + K&N drop in + removal of one mesh screen . The system works well . Cannot say if power is increased but I read around the forum a lot before deciding there was not much to gain by doing anything else.
Someone actually did some 1/4 mile runs that showed the RB was good for 0.1s at most. A couple of others were slower than stock .

Only drawback with the duct is that the filter needs to be taken out fairly regularly (I do it at each oil change) & slapped against something flat to get rid of all the road grit .

does removal of the filter in the duct require removal of the front bumper?

does removal of the filter in the duct require removal of the front bumper?

No filter is in the stock intake box

thanks for clearing things up. The thread just seems to clarify that intakes for our cars are just noise makers and make the engine bay look good.

Part of the problem is that you can't dyno the car and get an accurate number on how the car will perform at 75 mph on the highway.


1) with the ram air duct on my car..wouldn't that prevent some air flow getting to the radiator and cause over heating? I have ms front bumper so the openings are alot larger than the stock bumper. It's high up, and out of the way. Even if it was in the way, it wouldn't begin to compare with the amount of blocking my intercooler is doing to the radiator, and my coolant temps are just fine with the cooling fan mod also installed (~175 - 185 degrees on a summer day while driving around).


2) Since the Ram Air duct was designed for the revi intake, wouldn't that prevent maximum performance some how with the stock intake? Some people claim that it works just as well with the stocky

It's doing the same job either way. The only question is if the stock box flows as well as the RB intake, and that question can be asked without involving the air duct...

One thing you will find is that the duct seals better against the revi intake than it will against the stock intake. You can seal it yourself though - but I don't think it'll be a big issue either way.

Thanks for replying so fast guys. Answered all my questions

1) The people that are claiming that there is no hp gain from the REVi have no basis to make that statement. They only got that from some of the other posters on this board who were surmizing that, but had nothing to back that up. The only two times I have seen printed dynoes the Revi unit by itself (no Ram Air Duct) in RX Tuner gained almost +10 hp with the lightweight flywheel run by Polak, a respected poster on this board in arguably the best testing situation possible (same car, same dyno, same position, same conditions), and another time Import Tuner put it in and got 3-4 hp from the mid to high rev range (1-2 on the bottm end). I'll believe printed material over what some posters might think.

2) You will be lucky to add 6-8 hp total with the 2 parts. Hell you would be lucky to add +20 hp total with all the NA add ons (air intake, hi-flow cat, cat back exhaust, pulley, ECU flash. That translates to about .1, MAYBE .2 seconds in the 1/4 mile. It's not the difference between losing by a 1/2 a car, and blowing someone away. Anybody tells you that an intake or an cat back exhaust on this car adds more than a 3-5 hp they are lying to you. And 3-5 hp you are not going to feel.

3) The ram air duct is located on the bottom of the top of the grille. it clears the license plate mount. Most of the air for the radiator will come in from the bottom opening (where the rotary symbol is located) below the top grille. The radiator sits low on this car. Hence they will be little effect with this add on.

4) The ram air duct works better with the REVi unit because inlet extends farther out. On the stock unit the inlet extends maybe an inch or two outside of the box. On the REVi unit it sits a good inch or two beyond that. It connects/lines up better with the Ram Air Duct unit, and you get less air loss.

2) Hell you would be lucky to add +20 hp total with all the NA add ons (air intake, hi-flow cat, cat back exhaust, pulley, ECU flash. That translates to about .1, MAYBE .2 seconds in the 1/4 mile. .

disagree here Fanman . with my mods (no intake or catback) i'm at least .5s quicker than stock over the 1/4 . About 4 car lengths by my rough calcs .
Also on the back straight of our loacal short course I used to get to 152km/hr in 3rd by the end of the straight - can now reach 164km/hr & bouncing off the rev limiter (not quite enough road to make it worth changing into 4th) .

Sorry, but a 12 km difference, if you are implying that that straight is around a 1/4 mile (400m) is around 7.5 mph. There are a lot of car with a turbo setup that barely give you a 7.5 mph difference. That equates to about .7 sec. difference in the 1/4 mile. That improvement from the NA mods is um-possible from this car.

3-4 horsepower over stock? For the price I disagree that the revi is better than stock. Usually during 1/4 timings it depends on the driver and i highly doubt that NA mods will give you 20 hp.

i think ill just save a little bit of money and go with the

-stock+K&N drop in filter+plus ram air intake

probably later ill upgrade to the revi intake

thanks for all the replys

...what gives? Are most aftermarket intakes just noise makers and are obsolete compared to stock?
I've got the REVI intake and air duct. I love them. Although I do not feel any difference, the sound alone, IMHO, is worth it. Even according to Racing Beat, themselves, there is an "average of 1.95 HP over stock."

I don't know much about your prior intake, but there's no way an intake, alone, could decide a race. There are way too many other variables--especially driver performance. I don't know anyone who can drive so consistantly as to measure the difference of a sinle intake system on the street.

If you want a little extra noise while keeping the OEM look under your hood, the REVI is a good system. It's pricey, but well built and designed just for the 8. This is important because some intakes actually cost HP among other issues. If you've got the money and want it--go for it. If you just want more sound--I've read that the K&N Typhoon v.2 works well and makes a great sound. Not to mention is a lot easier to install and maintain...

2 cents.

Your call.

I think +20 hp is doable.

Ram Air Duct
REVi Air Intake (Together with the Ram Air assume +5 to be conservative)
AP Pulley (+2)
RB EMU Flash (+5)
Hi-Flow Cat
Cat Back Exhaust (+8 hp with the hi-flow cat, and you are right there at 20)

Definitely think 20 hp is doable, but be aware at that point you have probably dropped about almost $2K. Changed the sound, haven't changed the reliability. Quite a few posters with similar mods have gone from about low 180's to low 200's in WHP.

But if you are looking for big hp change for cheap then Nitrous might be your way to go.

Sorry, but a 12 km difference, if you are implying that that straight is around a 1/4 mile (400m) is around 7.5 mph. There are a lot of car with a turbo setup that barely give you a 7.5 mph difference. That equates to about .7 sec. difference in the 1/4 mile. That improvement from the NA mods is um-possible from this car.

just thinking this through - the other difference was worn out 225/45 vs new 235/40's . The groove depth of the smaller tyre was about 8mm more than on the larger tyre so I didn't think the two were that far apart in diameter . The tyre size diff will account for some of it though.

As far as the 152 km/hr speedo reading went i'm very sure of that as i was comparing notes with my mate in his toyota Soarer & we both hit the end of the straight at the same speed.

BTW - with my G-tech (1/4 mile) I consistently get over 100 mph terminal speed . Tyre size does not come into that .

has anybody ever posted timeslips for modded NAs? trap speed more than ET, is a good inicator of power. if there are 8s out there making a true 200whp then you would expect to see them trapping from 97-100.

has anybody ever posted timeslips for modded NAs? trap speed more than ET, is a good inicator of power. if there are 8s out there making a true 200whp then you would expect to see them trapping from 97-100.

LOL - just edited my post before your one came up

I think you could even get 25-30 hp with all the mods fanman listed, the hi flow cat from RP adds 10hp, i havent got it dynod since the super cat but you can really feel it, everyone thats rode in my car can even feel it.

thanks for all the replys guys

I have a problem with every intake I look at.
Stock airbox is ok, but if you really look at, the filter sits really far forword. The oval on the air box has two tap/flap things that stick out for some reason. Nothing inside is smooth. The box looks like it was built to get air directly from the oval. So why is the box so big and heavy? I dont know if it takes advantage of the entire box.
The RB has the bell that sticks out far like stock, I dont see how ramming air into the box would help a great deal unless it can use the air as fast as it is comming in. On the stock box you can atleast force air strait down the pipe.

This is what I see atleast when I look at them. Look at how a vacume works. They are almost always a triangle shape towards the suction. I wonder how hard it would be to suck up a pile of dirt if you hooked the shopvac to the stock airbox and stuck it in a pile of dirt. Would you get to much turbulence? Maybe I'm just crazy.

I think SR had the right idea, but he should of made the intake mount crooked so he could put the oval inlet right in the center.

Maybe I'm just crazy.

hmmm should I answer that or not ? he he

I like the mazdaspeed design - keeps the larger surface areas & filter away from the heat of the engine . Only drawback I see is the PITA to clean the filter .

dont forget the rb flash now available---20 hp is conceivable with it and a few other mods.
olddragger

dont forget the rb flash now available---20 hp is conceivable with it and a few other mods.
olddragger
add that to a LW Flywheel & you have got quite a big improvement from stock - perhaps almost matching a poorly tuned greddy turbo setup ........

I have a question regarding the REVi intake...from what I've read on it, I don't understand why exactly the VFAD needs to be removed, at least from a physical installation standpoint. Is there any reason why you wouldn't be able to just simply drop the REVi box right in place of the stock box and leave the VFAD in? I've read that the REVi has a longer inlet mouth, is this why? Would it be too long and start shoving the VFAD hose back in the engine bay inlet opening?

I have a question regarding the REVi intake...from what I've read on it, I don't understand why exactly the VFAD needs to be removed, at least from a physical installation standpoint. Is there any reason why you wouldn't be able to just simply drop the REVi box right in place of the stock box and leave the VFAD in? I've read that the REVi has a longer inlet mouth, is this why? Would it be too long and start shoving the VFAD hose back in the engine bay inlet opening?

It doesn't NEED to be removed. In RB's statement they took it off because it is a restriction point. They claim it is used to reduce noise. Unfortunately at the same time it restricts the incoming air a bit. That is why they removed it.


From the RB site :

"Even if the VFAD unit is fully open, inlet air is still somewhat restricted; so removing the entire intake assembly removes one restriction from the intake tract. But, as long as the stock air box has its relatively restrictive inlet mouth, the stock intake duct assembly should not be considered a serious restriction. If you were to simply enlarge the air intake opening on the stock air box, and left the stock air duct assembly in place, this would still maintain the restriction that you would have had with the air box. With the installation of the REVi Intake, we remove the entire stock air duct assembly. The only negative from removing the air duct assembly is a slight increase in noise, with our measurements indicating about 2-3 db (A) increase."

also too, you need to remove the VAD to install the Revi.

also too, you need to remove the VAD to install the Revi.

Didn't Fanman above just say that you do NOT need to remove it? Now I don't know who to believe. The reason why I'm asking is because I don't care about getting an intake for power...just for a slightly more aggressive sound, period. And I am completely against taking apart my bumper and then risking body parts not fitting together as tightly as they do currently. This is why I really want to know if it's even necessary at all to remove the VFAD, because everything I read shows that there's nothing physical behind the bumper that's somehow tied to the REVi box. By that I mean that it doesn't seems like you need to connect a hose from the REVi to something behind the bumper, etc etc. And if the REVi has no problems fitting against the VFAD hose inlet in the engine comparment, then it would seem like I should be able to just drop a REVi box in place of the stock box and call it a day. I never did look at the REVi very hard before because I thought you absolutely HAVE to remove the VFAD. I'm sold on it though if you don't.

That was straight off the RB website. If you don't want to take it off, then don't. The reason RB did it was they did not care about the extra 2-3 db of noise and the VFAD was a restriction point.

You DO NOT have to remove the VFAD to put on the REVi.

Thank you very much Fanman for the answer! I think I see a REVi in my engine bay pretty soon.

If you aren't going to remove the VFAD, You are going to have to find a place to mount the vacuum canister and find a way to route the hoses from the TB to the VFAD

I know that the manual has all this extra complicated hosing, but I'd be installing it into a 04 AT. So is it still applicable to the AT?

Well, you luck out then. The ATs don't come with a VFAD so no worries about pulling the bumper off :cool:

Also on the back straight of our loacal short course I used to get to 152km/hr in 3rd by the end of the straight - can now reach 164km/hr & bouncing off the rev limiter (not quite enough road to make it worth changing into 4th) .

Congratulations . . . you have become a better driver. The $$ you spent on track days did more than the $$$$ you spent modding.

Disclaimer: I have no data on which to base the above statement, it was pulled entirely out of my ass.

Congratulations . . . you have become a better driver. The $$ you spent on track days did more than the $$$$ you spent modding.

Disclaimer: I have no data on which to base the above statement, it was pulled entirely out of my ass.

Well I'd like to think my driving had improved that much but I assure you this is not the case .
Add to this a 1/4 mile time of 14.4 @100 MPH & 0-60 of 5.85s . Plus Comparing vids of my tach vs a couple of others that have been posted here confirms that my 8 is faster than your 8 HA HA LOL

Well I'd like to think my driving had improved that much but I assure you this is not the case .
Add to this a 1/4 mile time of 14.4 @100 MPH & 0-60 of 5.85s . Plus Comparing vids of my tach vs a couple of others that have been posted here confirms that my 8 is faster than your 8 HA HA LOL

wow,

trap speed at 100mph... i have to disagree your ecu is doing something for you...

our mods are close.. highest trap speed i have seen is 97.5 and i have to admit to a bit of an elevation change. in favor of speed..

beers :beer:

pm

Swoope ,
thinking about why i consistently get high trap speeds - (my best is 101.7MPH) . I think it is to do with my higher 3rd gear ratio . JDM spec cars come with different 3rd gear.
When you change into 4th you lose a few mph before accelerating - I don't have to change into 4th on a 1/4 mile run .

Swoope ,
thinking about why i consistently get high trap speeds - (my best is 101.7MPH) . I think it is to do with my higher 3rd gear ratio . JDM spec cars come with different 3rd gear.
When you change into 4th you lose a few mph before accelerating - I don't have to change into 4th on a 1/4 mile run .

ah,,

yep. that would do it...

do you have the ratios for you trans?

beers :beer:

dug this out of an old thread where we had a discussion on this . Looks like 1.53 to me .
http://www.rx8club.com/attachment.php?attachmentid=89648

Hey does ne one kno where to get the Revi+Duct for the cheapest price, i know that mazdaparts.com is cheap but i still dont have gold status and its been for ever. I really want me Revi

Won't add any power, but will give you a little ram air effect. Will also add a little intake sound.

...and foliage if you have autumn where you live. Stay stock.

...and foliage if you have autumn where you live. Stay stock.

Not really

Hey does ne one kno where to get the Revi+Duct for the cheapest price, i know that mazdaparts.com is cheap but i still dont have gold status and its been for ever. I really want me Revi

www.rx7store.com, they have a discount on RB stuff.

Thanks Fanman

http://www.good-win-racing.com/Mazda-Performance-Part/60-1096.html !!!! that is the cheapest price ive found it for! beats rx7store!!:rock: