rowteree

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?

Jax_RX8

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

rowteree

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?

staticlag

Were there any passengers either time?

romycha1

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.

rowteree

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

rowteree

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

Jax_RX8

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

rowteree

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

DarkBrew

Hard to beat stock on the '8

https://www.rx8club.com/series-i-aftermarket-performance-modifications-23/real-world-effects-performance-83785/

rowteree

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

Brettus

iTrader: (2)

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 .

Brettus

iTrader: (2)

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

rowteree

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

Brettus

iTrader: (2)

No filter is in the stock intake box

mysql101

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.


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).


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.

rowteree

Thanks for replying so fast guys. Answered all my questions

Fanman

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.

Brettus

iTrader: (2)

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) .

Fanman

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.

rowteree

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

Phantom Menace

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.

Fanman

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.

Brettus

iTrader: (2)

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 .

'ringmeister

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.