Is a 30% increase in power possible with CAI and an Exhaust?

[Boags]

Hi Matt,

Great choice of MX5! NB8B FTW! What colour?

ITB is individual throttle bodies (or something close to that). Basically instead of having an intake plenum feeding all the chamgbers with air, you have short intakes on each cylinder. This means throttle response is amazing and there is almost no resriction from plenums and long piping etc.

NOTE: Mazda's 113kw for the NB8B is at the flywheel. No one here will talk about flywheel kw becasue once the engine is in the car you can't retest after installing new mods. We all talk about Rear Wheel (rw) kw. This is what you measure on the dyno. When you put yours on as standard expect around 80rwkw (I think).

With lots and lots of (street) mods a fellow forumite reached 98rwkw with his NB8B. That's the most I've heard of for a non-turbo street going MX5. The race guys have road legal cars but the car is built to race.

This post was more a helper for anyone looking on who was a bit confused. Not aimed directly at Matt. Please correct me if I'm off with anything.

Boags

[Steampunk]

It may be possible getting a 30% increase IF a car has reeeally crappy designed intake and exhaust system, but the MX-5' system is pretty good from factory, so the mechanic is doing a song and dance in order to sell stuff.

Put him in his place and see if he'll back up his claims.
Tell him that if you buy his stuff, and it doesn't reach the magic 30% increase then you want 20% of your money back, but if it does reach 30% then you'll give him 20% more ontop of what you paid.

[bruce]

You heard him completely wrong. He said he will make a 30% 'profit' if you install a CAI and exhaust.

[Hot Rodders]

You heard him completely wrong. He said he will make a 30% 'profit' if you install a CAI and exhaust.

ROFLMAO !!!!

Thanks Bruce, I didn't need that as I was taking a mouthfull of coffee.

[philz]

30% increase you will be looking at a low pressure turbo setup in NA form.

When people ask how much power do i/h/e [intake, headers, exhaust] mods gain for a natural aspirated car, I say don't expect more than 10-15kw, and the power is not what you are after, imo it's about the response of the engine with a much more free flowing system.
If you want to see a massive increase in power - bang for buck- go with turbo.

30% increase with [i/h/e] on a stock turbo car is possible ie/ evo 8, GT-R etc.

[FMS01]

Maybe it's an expensive cold air intake thats making the air cold through the addition of NOS. that would deliver on his power claims...without the exhaust bits even...

Julian

[Hellmun]

Last time my car was tuned it reached 105kw atw. That's racing beat 4-1 headers, secondhand 2.25" SP motorsports exhaust, modified mania no-drill CAI with a ducted/shielded box from the foglights. Though I'm also using one of the original Mx5 Mania ECU's upgraded to run a MAP sensor. I've never had the head off my car....

[matt9111]

Cheers for all the replys


Hmm....I see. I'm picking my car up tonight from its major service, so i'll chat to him about it tonight.

I thought an S/C was more bang for you buck? Always constant power out of corners, no rush of boost, I thought they we're good for 140rwk for around 4K?

[Boags]

Last time my car was tuned it reached 105kw atw.

On Mania's dyno? Isn't it a little... Optimistic?

How is the sound with the exhaust? I usually hate the rasp of extractors, not many sound good IMO. But I realise if I want to go that route I'm going to need to put up with it to squeeze the power out. Long way down the track at this stage though.

Matt - Can Of Worms. Turbo will produce more power/$ than anything else. Whether or not the turbo set up has years of lag and terrible drivability, the fact remains it is the cheapest power.

[Hellmun]

Last time my car was tuned it reached 105kw atw.

On Mania's dyno? Isn't it a little... Optimistic?

How is the sound with the exhaust? I usually hate the rasp of extractors, not many sound good IMO. But I realise if I want to go that route I'm going to need to put up with it to squeeze the power out. Long way down the track at this stage though.

Matt - Can Of Worms. Turbo will produce more power/$ than anything else. Whether or not the turbo set up has years of lag and terrible drivability, the fact remains it is the cheapest power.

My car wasn't tuned on the mania Dyno

The car actually only made 92kw the last time I had it on the mania dyno, though that was only given a short tune. I think they only got to spend less than an hour on it after replacing the circuit board on the ECU and wiring up the Map sensor to the ECU. The car used to blow a lot of fuel smoke and get <300km to a tank. 2 Months ago I had the money and time to get it retuned by Daniel and it made a big difference..... Back at 400-450km's a tank and a lot more torque.

You come to get used to the rasp....I used to absolutely hate it too.

If someone wants to organise a dyno day in Wollongong/Sydney I'll be up for it. If I get off my arse I might finally take the a/c unit out and the car should make even more at the rear wheels... I have a cat deletion pipe for it now too.

[Novice1]

I, am having a 2.5 inch cat back exhaust system fitted to my car next week, Magnaflow to be exact.
I, will be having before and after dynos and tuning after fitment.
Mind you my car is turbo. But, it should be interesting to see the gains.
The boost will be raised of course after the after market exhaust.
But, may be able to extrapolate something from dynos.
Cheers Novice1 aka Ron

[Fatty]

Ron, my 2.5 inch exhaust (plus a timing bump) gave me around 20rwkw increase on my turbo na6. so i think you'll be pleasantly surprised.

[Novice1]

Re turbos and lag. I, have had two other turbo cars both had the
dreaded lag. My present car doesn't have any lag at all, so it is possible to have a turbo car without lag. In this case its a Garrett T28 turbo, thoroughly recommend.
CHeers Novice1 aka Ron

[Novice1]

Ron, my 2.5 inch exhaust (plus a timing bump) gave me around 20rwkw increase on my turbo na6. so i think you'll be pleasantly surprised.

So your NA went from what to what with Zorst and timing?

Oh yeah and my turbo is abnormal very linear.
Cheers Novice1 aka Ron

[Fatty]

98rwkw to 118rwkw. i didn't fidle with the boost (or anything else), which is only at about 6 or 7 psi. so there is plenty of wiggle room for more power there, easilly.