Speed3 Exhaust Tip very black - problem?

[MS3West]

Looked around to see if this had been discussed already in the forum. Couldn't find it.

Got a Speed3 this past weekend, and have noticed my exhaust tip has turned completely black.

Is this normal? Or, did I break it already!(nervous)

400 miles on it so far.

Thanks

 

[Mspeed3]

our cars run rich so they don't detonate. When ever you run full throttle watch ur rearview you'll see puffs of smoke. Its normal, I think mazda knew people would mod these cars so that is why they run the way they do. Dynotune or wait for cobbs accessport

 

[qwertyspeed3]

our cars run rich so they don't detonate. When ever you run full throttle watch ur rearview you'll see puffs of smoke. Its normal, I think mazda knew people would mod these cars so that is why they run the way they do. Dynotune or wait for cobbs accessport

Doesn't a CAI help alleviate the black tailpipe a bit?

 

[Loose]

Looked around to see if this had been discussed already in the forum. Couldn't find it.

Got a Speed3 this past weekend, and have noticed my exhaust tip has turned completely black.

Is this normal? Or, did I break it already!(nervous)

400 miles on it so far.

Thanks

Noticed it on mine as well.

 

[$inCitySpeed3]

Doesn't a CAI help alleviate the black tailpipe a bit?

no

 

[Mspeed3]

no because the ecu will adjust more fuel for more air to keep same A/F ratio. The only way you can change it is to do some tuning.

 

[dommo_g]

I know when I put a catch can on my Neon, the black tailpipes went away. But the PCV system is such as that a lot of oil would get forced out of the PCV valve and right near the throttle body. So the oil would get sucked into the chamber, burned and the reside would accumulate on the tailpipe. I haven't had time to see if the MS3 would benefit from a catch can, and I haven't really searched the forums to see if it's even an issue with this car. But it's something to think about.

 

[Japaneezy]

no

i dunno... i put mine on last week and it solved my black tailpipe problem. It used to get black as night within a day of washing it. ever since i put the mazdaspeed cai in, no soot at all =)

 

[$inCitySpeed3]

well your the first one yet i have read in three forums...

 

[RODSCALIP5]

I don't remember where, but I read a thread that said the dealer re-flash cleaned the tailpipe.

 

[Japaneezy]

I don't remember where, but I read a thread that said the dealer re-flash cleaned the tailpipe.

i read that thread too. and the CAI does help. there are others on this board who got similar results. it leans out the A/F ratio so less soot is produced.

 

[whitey4311]

It wouldnt lean the mixture by adding more air its going to better match the fact the engine is tunned rich yet the stock box starves it for air.

Starving an engine for air creates a lean condition however the engine is tunned rich meaning there is unburnt fuel hence that black crap.

From my understanding giving the engine the amount of air it is tunned for via CAI the mixture should then be better balanced.

 

[Damian]

It wouldnt lean the mixture by adding more air its going to better match the fact the engine is tunned rich yet the stock box starves it for air.

Starving an engine for air creates a lean condition however the engine is tunned rich meaning there is unburnt fuel hence that black crap.

From my understanding giving the engine the amount of air it is tunned for via CAI the mixture should then be better balanced.

You've got it a little backwards. Starving an engine of air forces a rich mix. If all else remains the same, the CAI will add more air, thus leaning the mixture out. However, if the ECU is trying to hit a A/F ratio number (I've seen the MS3 at around 9:1, which is pig rich), it will just add more fuel. I do have a feeling, however, that Mazda designed the ECU programming to accept a certain amount of extra air at the same throttle position (this is where an electronic throttle comes in handy). If it were a mechanical throttle, the ECU most certainly would throw more gas at it immediately. This jives with the reports that people who have installed the CAI have had an increase in gas mileage. It means the engine isn't using more fuel to create the extra power. It's probably running closer to 11:1. Still, ideal AFR for gasoline is 14.7:1. Not the safest bet, however. I wouldn't lean a turbo much past 12:1 however. If you don't want to turn the turbo into a block of molten metal, you'll always be rich, and always eventually have a black tailpipe.

 

[whitey4311]

LOL, maybe I dont understand it very well then.

With my Nitro RC engines I know that less air means its lean and adding a higher flow air filter means you need to richen it up a bit.

The way I figured it was that I read these Mazdas are tunned rich yet the intake is restricted so that isnt balanced as well as it could be. This was why I thought adding more air to the engine means it woudl accomodate the already rich tunned motor.

With the computer envolved I am lost so thanks for setting it straight, I am still learning about this stuff.

 

[Damian]

Well, no, any engine, including an RC engine, less air for a given amount of fuel richens the mixture. When you adjust the needle valve on an R/C engine to reduce the amount of fuel bleeding into the cylinder, you are leaning out the mixture, increasing power (to a point), increasing heat, and decreasing lubrication, eventually leading to the piston becoming one with the cylinder liner.

If you open that needle up - and you've probably done this with the motor running, the whine of the engine gets lower pitched, and it won't rev as high. As you keep opening it up and making it richer, the engine starts to choke a little, running rougher, and in the case of a nitro engine, spitting castor/synth oil all over the damn place.

All of this is exactly the same in the car. The only difference is that instead of spitting oil out all over the lexan, unburned and partially burned hydrocarbons collect on our tailpipes.

 

[whitey4311]

I dont know man because if I lean my Nitro engine by decreasing air to the carb it runs lean not rich.

You dont adjust fuel amount to the carb you adjust amount of air to the carb to match the fuel mixture. This is in RC but then when it comes to real cars the computer must adjust fuel delivery and this is where I am lost.

For what I understand less air to the carb on the top end means a lean condition not rich.

I either am way off the chart here but the only way this makes sense to me is that adding more air to the engine to balance the already rich tune on these MS3's makes for better fuel usage and tune. All this should result in less carbon build up on the pipe due to a better fuel burn and more power due to it not being so rich.

I am far from an expert on any of this so I appologize if I am wrong but relating this to RC is similar and from what you say isnt what I find to be true when tunning an RC engine.

 

[Damian]

2 stroke or 4 stroke and what are you adjusting on your engine?

 

[whitey4311]

Yeah that is where I just say I am a noob because I dont know that much about 1:1 car engines.

RC is 2 stroke so there is a big difference.

So then on these cars we are leaning them by adding more air via a CAI?

It seems opposite to me but you know more then I do so I will let you teach me, lol.

 

[Damian]

There isn't a big difference. Not all R/C is 2 stroke. However, depending on what kind of 2 stroke nitro engine you have, you might have one, two, or three needles. These needles control how much fuel is let into the mix at various throttle points, not air. The only thing that controls air is the idle set screw (how far open is the carb at the lowest end of servo movement, and the servo set screw, which ensures the carb is completely open at full throttle.

You adjust the low speed needle at idle. Less fuel is leaner and the engine idles faster. More fuel, richer, slower idle. Same goes for high speed needle. This exact same thing happens in a car, but its handled by the computer and fuel injection.

You are correct when you say adding air helps to lean the MS3's engine and should result in less black soot.

 

[whitey4311]

gotcha thanks man.