Mazda Rotary Club

I\'ve read on a few posts that exhaust and induction kit are ok for standard FDs with factory fuelling.

My Rex has a Nurspec cat back as its only mod - and I\'m hoping for many long and smokeless years of driving.

However I want some more noises, so:

Which is better for engine longevity - aftermarket BOV or induction kit? Or will neither make a discernable difference?

To be honest, I doubt either will improve your engine longevity (or shorten it).  Induction can make quite a sweet noise if you\'ve got the air pump connected (here it through the filters) but a BOV will make a bigger noise!

Depends how chav you want to be, i.e. a BOV is higher up the chav scale than induction (in terms of engine \'enhancements\') :D

HTH
H

Well I\'m only 13% Chav according to that quiz elsewhere on forum :)

Fitting an Apexi on my MR2 Turbo transformed the car, from whooshing on gear change - to a drool-worthy hissing on start up (sounded like the car was inflating the engine!)

Anyone recommend a good kit?

I used to swear by Apexi and their maintenance-free goodness, but HKS seems the order of the day on planet Rex...

i have got a blitz cat back zorts and twin blitz filters with a blitz BOV n it sounds quality i love it you can really hear the turbo\'s spool as it is about to take off. :D

 :wave :wave

I\'ve seen a few second hand kits about - but never know how tired the filter is...

Though a mate of mine argues the more filthy the filter, the better the filtration - any opinions?

Fitted the Apexi Power Intake a few weekends ago and it\'s done a few things...

1) Excellent sounds - whooshing, whining (spooling turbos) and \'all hell\'s broken loose\' on full boost.

2) No dyno to show it but I\'m sure it\'s sharper in response and got more grunt.

3) Improved mpg - gone up to ~22 from ~17.  

I upped the base duty on the map to reduce the risk of running lean and am stearing clear of full boost towards the end of 3rd and 4th gears until it\'s remapped once the v-mount and bits are on.

With just a cat-back you\'ll be fine adding induction on stock ecu.

It\'s not a huge job to fit either although the spring clips on the hoses are a biatch!

You got IMPROVED fuel economy from fitting the Apexi\'s?

Hell, sign me up for some of them :eek:

Ducting is a good idea if running the apexi

I\'m considering switching back to the Stock air box as the weather is getting hotter now (hopefully)

Will you be using the stock air filter as well Dave?
Can anyone supply pics of Apexi induction please as i have a used set and just need to get to see the layout of the pipes etc.
Thanks Bob

QuoteOriginally posted by davefrith
Ducting is a good idea if running the apexi

I\'m considering switching back to the Stock air box as the weather is getting hotter now (hopefully)

This is true although leaving the standard air duct in place will help a little.

I\'ve seen a plate placed behind the filters to stop them drawing air from the turbo area.  Not sure if this is a great idea though as it will deprive that area of some air-flow...

I might go for a K/N on equivilent

I am just concerned that induction kits seem to just suck in hot air

QuoteOriginally posted by iaint
This is true although leaving the standard air duct in place will help a little.

I\'ve seen a plate placed behind the filters to stop them drawing air from the turbo area.  Not sure if this is a great idea though as it will deprive that area of some air-flow...

hmm thats an idea

QuoteOriginally posted by davefrith
I am just concerned that induction kits seem to just suck in hot air [/B]

Cold air induction, mmmm.

Cheers, I\'ll expect mine in the post soon  thanks mate  :D

Nah, it wouldn\'t fit through the letterbox :p

As with all induction kits, the cold air feed only seems to be a real issue at low speeds/idle, once your travelling theres plenty of cold air coming into the engine bay anyway (unless your turbos glow white 99% of the time........

I know what you mean about hot air going on, it\'s not ideal, but unless you build a fully enclosed system with cold air in only then I would speculate as to how effective it would be (don\'t forget the intercooler plays a big part in air temps).

If I didn\'t have the Apexi system I would go for this little number from the US:
http://www.m2performance.com/pintake.htm

I\'m pretty sure it runs twin K&N\'s internally and draws in cold air from a gap by the radiator.

As a seperate suggestion, you can draw cold air in from either side of the radiator.  Stock cars with stock rads have a wedge of foam stuffed down the side, about 20-30mm thick.  If you remove this and fabricate up some fibreglass up to the intake I\'m pretty sure you could get something to work.  This obviously wouldn\'t work with the Apexi as the filters are so big you\'d need a massive box to house them...

HTH
H

See this goes back to my question about engine protection - factory filters are usually the best way to feed the engine as Mazda has spent a few quid researching them.

However, most cars dont run as hot as RX7s, so aftermarket filters dont do any damage (just a drop in bhp).

So - are aftermarket filters BAD for the RX7?

Mazda\'s final descision is as much based on economy and noise reduction as power output, it\'s all a compromise, where as for us as aftermarket tuners, we don\'t have to compromise. :)

I wouldn\'t subscribe to saying they were bad per say, however I would say that the colder the air you can get coming in the better if you\'re running higher than stock boost (important point).  For stock boost I don\'t think it makes a real difference.

Without having accurate, consistent data about air temps between an enclosed system and an open one it would be very subjective as to whether it\'s worse.

Being able to keep air temps at a consistent temperature is fairly important, especially in high boost application.  Having a consistent intercooler (FMIC or charge cooler - neither of which suffer as much from heat soak as an SMIC), fresh air intake and venter bonnet are probably the three things you could do to make it as consistent as possible, even in hot weather.

HTH
H