Sorry mine aren't too floppy so i've never tried that but can you use them as parachute during drag racing?

On my M3 I had a ceramic cat break up and it sound like rocks in the exhaust. I just banged on it with a rubber mallet and could duplicate the sound. After I removed it, a piece had blocked the pipe down stream.

Mine aren't that floppy either so I tried the no exhaust ride instead. Results are that it was so loud that it felt it had a lot more power then it actually did so I'm not sure if the exhaust was clogged or not. I will continue to investigate until I decide to buy the wideband and boost gauge (and maybe MS2) but in the meantime here is a little video of the car when it was working great:


Thanks for your help!

Wait wait you're RACING this car with no wideband or boost gauge? :facepalm:

This will surely end well.

Expecting the "there is a lot of smoke out the exhaust and it sounds like a subaru" post in a week or two.

Alright guys, the car has 180 000km and has perfect compression. It has a Powercard - yes I know it is far from the best management - to control the injection. The ignition is still OEM and if detonation is detected there is a knock sensor that will retard ignition timing. For the boost gauge, well this is no turbo, there is no wastegate. The only way to change boost would be to change the pulleys and I am pretty sure that it won't happent even if i don't have a boost gauge. The wideband would be nice but with the narrowband I am supposed to be at 14.7 on the whole powerband and that's it. I know it is far from the perfect setup but it at around 7psi this is not an agressive one.

Holy christ thats why its slow. You DO NOT want to be at 14.7 when in boost. Jesus ------- tits in a scrotum, richen that baby up and buy a god damned wideband for tuning.

The problem is your blown motor. replace it an you'll recover your lost power for a while.

Did you remove and inspect the catalytic converter for broken ceramic blocks or not? If you don't see any that look broken then the pieces are all in your muffler now or stuck at the elbow in the exhaust pipe. That's why the rattle stopped.

You are not supposed to be at 14.7AFR on the whole powerband. At max boost you are supposed to be at 11.5-12.0AFR. You need to buy a wideband 02 sensor and gauge now. Then you need to see what exactly you are running for AFR's. If you run 14.7AFR in boost you will cause your motor to explode.

.

Weak coils are probably the single most common issue with 99-00 miatas. A weak coil will then kill your catalytic converter which cloggs and robs even more power.

I have removed the "middle pipe" witch has the catalytic converter and resonator on it. Both are welded together so I can only see the side of the cat where the gases enters and it seems perfect. It has been raining a lot these days so I can't work on the car very much but the muffler makes a ratteling noise when I hit it with the rubber mallet. I will investigate more when the sun finnaly comes out.

I will probably buy the wideband soon if all else fails.

Thanks for the help!

NO!!!! You need to order the wideband TODAY. It is not safe to drive a car with forced induction without being able to monitor the AFR's correctly. If you can not afford a wideband currently then stop driving the car until you can. Because if you can not afford a wideband you most certainly will not be able to afford a new engine when your current motor blows.

When they check you out at the register for the wideband don't forget to get a side of motor.

Most people do a facepalm just on the internet... I'm doing a face palm in real life while reading this.

Found the problem. Catalytic converter was broken. It's empty now and everything is back to normal!

Thanks!

In for the blown motor thread.