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Hey,

I was contemplating all the CIA ideas and every time someone said that the resonation chamber is crucial and if its not there your engine blows up and catches fire and the rest,
So what I did was compare three intakes on the dyno,

ARC intake (second hand but new $450)
Factory intake with resonator cut off and sealed up
Factory intake as Mazda intended


All these intakes were tested after a long drive and all with in 5min from start to finish so the intake temp isn’t a factor
Also the midrange dip in the arc intake curve corresponded with a huge lean out of AF ratios which the dyno operator said could be tuned out with engine management,

I would also like to point out that the midrange of both the factory intakes is almost spot on the same but the peak power if the modified one was down 10hp

Overall the factory intake still looks best though....

$450 for a smidge more bottom end, a big hole in the mid range and no extra top end.....hmmmm that's good value. I hope it at least looks a bit blingy.

Hmm, so the dyno says no midrange difference, but the resonator is definitely helping the top end.

I'd be wanting more info before jumping to conclusions...

Where was the intake temp sensor? Was there a dyno fan, where was it located? Was there heatsoak (although the last run appears to be the stock one!) Was the bonnet raised? Does the car have other mods>?

Even so, looks very close between the lot of them.

As said about it leaning out in the midrange, i reckon that intake would offer some pretty good gains with a computer, and i do wonder if the other changes might too.

Makes me kinda glad im running a computer with my car (or will be)

white1.8 wrote:I was contemplating all the CIA ideas

Who told you the CIA was working on intakes.. i will have to get you killed now

Sean wrote:I'd be wanting more info before jumping to conclusions...

Where was the intake temp sensor? Was there a dyno fan, where was it located? Was there heatsoak (although the last run appears to be the stock one!) Was the bonnet raised? Does the car have other mods>?

Even so, looks very close between the lot of them.

Where is the best place to put the intake temp sensor?
In the factory set up, its before the airbox. A lot of aftermarket one put is after the airbox, middle of the plumbing or even close to TB. I assumed closest to TB would be the most accurate?, considering all the heat soak between the airbox and the plumbing.

What do you reckon?

I was refering to the Dyno's sensor - It adjusts the power output depending on ambient and intake sensor temps.

In relation to the cars sensor though, if you're running a stock ECU, I'd expect the best ocation would be close to the stock location as the factory would have tuned to car according to temp changes/heat soak/etc present in that location.

Sean wrote:In relation to the cars sensor though, if you're running a stock ECU, I'd expect the best ocation would be close to the stock location as the factory would have tuned to car according to temp changes/heat soak/etc present in that location.

And if you're not running a stock ECU?

It varies dependant on your set-up and the type of sensor the ECU is using.

My opinion which seems to be shared by most tuners I discuss it with is that you want the sensor in an area that will give a true reflection of the temp of air being used by the engine, and a location that give solid repeatable results.

Mounting the sensor in the intake manifold sounds like a good idea, but i can get dodgy figures from heatsoak, particularly on hot start-up in warm climates, even summers in NSW can see the hot start effected by manifold mounting - I made this mistake myself once before...

So I think the best is as close to the intake as possible without getting the heat soak, I ended up mounting mine about 10cm infront of the throttle body in my intercooler piping. If you are running forced induction and a cooler, you definately want it after the cooler and as close as practicle to the throttle body while keeping it away from foreign heat sources. I found the position 10cm from the throttle body was very good for me on the mx5. Remeber though that you will need to tune the car with the sensor where you intend to keep it, particularly the starting and temp enrichment settings

"Mounting the sensor in the intake manifold sounds like a good idea, but i can get dodgy figures from heatsoak, particularly on hot start-up in warm climates, even summers in NSW can see the hot start effected by manifold mounting - I made this mistake myself once before..."
Sean,
It good to see other people making the same mistakes, I done feel so stupid now . I mounted mine in the dummy throttle body at the intake manifold and it always read hot ( the idle control valve mounted at the base of the ICV is heated by the engine coolant). Mine is now mounted in the intercooler pipe work after the IC.

From what I’ve read, once you change any part of the Mazda standard setup you compromise the effect of the resonator.

Sorry if this is not on track with the current thread, but has anyone tried to attach a stock resonance chamber to aftermarket intake tubing?

*waits for the arguments about calculated length and size blah blah blah....*

I can't imagine it would work well.

Thanks for the answer there Sean. I was thinking about this very topic the other day and had roughly the same logic.