alex zhuk

iTrader: (1)

ok so i am doing my springs and decided to take the walls out in the air box..... i saw that it is a good idea to reset the computer but im wondering do i have to reset the KAM as well?

thanks


and how long would you guys say it takes for some tein-s to settle in and get to its lowest drop?

alnielsen

iTrader: (4)

I don't believe you need to reset the computer. If it senses any changes, it will automatically compensate for them. I never did a reset when I did mine.

alex zhuk

iTrader: (1)

heard some ppl got a rough idle for about 100 miles.... a way to pervent this would be to reset it...... so just wondering

alnielsen

iTrader: (4)

I removed the walls and one of the screens without any issues.

SayNoToPistons

iTrader: (8)

I removed the walls and one screen without resetting the ECU. No problemo.

alex zhuk

iTrader: (1)

you mean the lil mesh screen that is going into the intake manifold?

i looked at that and it looked like there is only one? is it better to take it out? cuz i only removed the walls and no rough idle yet.

also how long would you guys say it takes for springs to lower to there right spot? cuz i throw my springs on yesterday n it looks like its sitting at the same height.

thanks

Solidtrance

iTrader: (2)

Check the DIYs for one about replacing springs. Look for a post about "pre-loading the springs" that should explain why your car is taking a long time to settle. Should be a quick fix for you.

alnielsen

iTrader: (4)

There are 2 screens. One is in the air box and one is located just before the MAF sensor. These screens are there to even out the air stream while moving through the MAF. They are also a restriction. I removed the one in the airbox because it was farther away from the MAF than the other. It is held in place by a snap on ring. Warming the ring will make it easier to remove.

Huey52

iTrader: (2)

I removed the two airbox interior walls (baffles) but left both screens as I feel they're needed for proper MAF-sensed airflow. No ECU resetting required and no rough idle.

kersh4w

iTrader: (3)

i removed both walls and 1 screen. i didnt touch the ecu, it was golden.

also, i removed 1 screen from my AEM intake. still golden.

DeViLbOi

iTrader: (1)

Removed both walls with no reset...no problems...

TZ250

Could someone explain why it's a good idea to remove the baffles in the airbox?

Generally the airbox volume is tuned to the correct resonant frequency of the power band, especially in port induction engines. Am I missing something?

mike[piston eater]

iTrader: (3)

well the japanese 8 didnt have the walls so they just put the walls in amerca to keep the intake sound lower

alnielsen

iTrader: (4)

If you look at a dirty air filter, you will see the dirt is all located at the center of the filter. This seems to mean that 1/4 to 1/3 of the filter isn't doing anything. Removing the baffles, opens up the fill area to air flow. It is believed that the baffles were put there to reduce noise in the intake.

TZ250

Engines have air pulsing in and out of the intake tract. The timing of the pulse is affected by lots of things, but the volume of the airbox has the biggest effect. When you change that volume, you change the timing of the pulse and can actually decrease the charge volume and hence the power, or move the pulse to a different spot in the power band.

Having said all that, I only know this as it pertains to piston power. How this compares to a rotary I'm not sure. But since they're both just different types of air pumps, I think the effect would be similar.

Some of the racers on the site may have more insight into this.

DeViLbOi

iTrader: (1)

Tz250 - What you are saying makes sense. However, the car was designed with the baffles not there. The baffle walls were inserted to comply with US standards and I doubt Mazda went back to retune the engine for the decreased airflow. That said...when I removed the walls I noticed right away a better throttle response and change in gas mileage. Some people have gone so far as to lock the VFAD open increasing those gains even more. The RX8 is starved for air it seems and this is one of those minor changes that you can make to help it out.

shaunv74

I tend to agree with TZ250.

Until someone posts up a MAF sensor data log of before and after removing the baffles any perceived improvements are just conjecture. There are plenty of aftermarket intakes for sale for the RX8 that actually lose power so I suspect you can easily do more harm then good unless you have real data on the impact of any change to the intake.

DeViLbOi

iTrader: (1)

So the 6mpg that I gained and the loss of the feeling of leaving from a stoplight and nosing over is "harmful" eh. Interesting concept.

shaunv74

I am saying using the word "feeling" to describe the benfits of a mod. is not valuable or meaningful.

while 6mpg is impressive you'd have to do a bunch of back and forth testing to show me that removing the baffles in the airbox is the only change that netted you a 30% increase in fuel economy. If that were truly the case Mazda would have yanked them a long time ago.

Again a data log of MAF sensor flow rate before and after on the same day and same temp. will tell us whether or not this is a benefit to the motor.

LGukas

iTrader: (1)

I removed the 2 walls one month ago... I lost the power on the low rpms. The car had little rough idle so i put the walls back. It wasn't good mod for me.

TZ250

As I said, I'm out of my water here as concerns renny engineering so please correct me if I step on myself. But let me blather for a minute. The volume of airflow is only very indirectly related to the size of the airbox. You could make the airbox a lot smaller and it would flow just as much air. But particularly in an engine with no valves, the peak of the reversion pulse from the airbox packs a lot more charge into the chamber. That's why the size of the box is important. The energy, duration, and timing of that pulse are directly related to the size and shape of the airbox. You could be absolutely right that Mazda simply ignored this. I don't know.

The same thing happens in reverse on the exhaust end. The low pressure trough of the pulse is used to extract as much gas as possible from the chamber.

As for the VFAD, based on my experience, locking an airflow device like the VFAD open will reduce power everywhere except at the very top of the power band. So on the track, great idea; on the street, not so much. If you use throttle bodies as an analogy, it's like assumimg larger throttle bodies will produce more power. They could if the engine design is wrong, but it's much more likely they will decrease power.

For NA port induction engines, getting these things right is important if you want the most power from your engine. The engineering is complex unless you're expert on a flow bench, and I give Mazda the benefit of the doubt until I see hard numbers to the contrary.

rotarymike

iTrader: (1)

Good God, someone interested in the SCIENCE of it all on the forum... what a rarity.

Intake tract tuning is indeed important on a rotary. It's why the 6-port models have 4 different settings to change the resonant frequency of the whole shebang. When the rotor closes off the intake port the reversion pulse produced is very strong, and the intake is tuned such that the pulse will arrive at the other rotor's intake port at about opening time, giving some inertial supercharging. I've seen 1 PSI positive pressure on my NA 2nd gens with a similar setup - on a calibrated (non-automotive) gauge.

Many people have played around with the intake and exhaust on the RX8... including Mazda. I think they got it right. When the experts at Racing Beat (who have access to Mazda engineers) can't really improve on either, you know Mazda finally did something right. Shame, really, since an RB exhaust sounds so nice... but for 5HP my money would be better spent on liposuction in terms of performance improvement.

kersh4w

iTrader: (3)

wow. to every NEW PERSON IN THIS THREAD, please continue to ignore what everyone on these forums already knows.

the baffles were put in to reduce sound.

go ahead and run around shouting with your hands on your ears. whatever.

alnielsen

iTrader: (4)

Pretty close to the perfect response. Oh, and you can't compare the Renesis with the 13B that was in the 7. They operate differently.

DarkAngel

Wait all this talk about the "Science of the Box" but yet the Japanese 8 doesn't have them? I dont know if that tells anyone anything.