B18C4 MB6 vtec crossover sound

[Guest Chris Rox]

Hi guys I've been told that this is the place to be for all things Civic so I am hoping you can help.

 

I have recently has a new exhaust fitted to my MB6. Originally the intention was to keep the cat in the exhaust but that didn't work out. The new exhaust is a (super dooper) Toyosport cat-back system off of eBay. But the key part here is I had to get a de-cat pipe. Now the only one I could find that was the right length was a literally straight throigh pipe and I have seen others that have bunged sensor locations.

 

My question is this...

 

Does it matter that my de-cat is straight pipe with no sensors tapped in to it and was there ever a sensor plugged in to the original cat? My mechanic says it doesn't matter about the sensor but I've left now not knowing whether there ever was one in the cat to start off with and really, as you guys have more experience, is this a problem that needs rectified.

 

Overall the problem that I am frustrated with is the apparant disappearance of my beloved cross-over sound.

 

Previously the exhaust was a fully standard system and all that was on the engine was a cheap induction kit but the engine sound was beautiful and the cross-over at 6k was volcanic! Now with this new "system" all I can hear is a change in engine and exhaust sound at around 4.2k and my cross-over at 6 has gone and it's a real struggle to hear now. There is certainly no Vtec punch anymore. The power doesn't seem to have change and I'm certain it hasn't lost any but i'm really dissapointed the awesome Vtec sound has gone. I have two videos to compare that I will upload and link later.

 

Any help will be greatly appreciated!

[Grant]

Ok ...

 

Firstly, you are right, here is all things civic (of the M variety) Secondly, can you fill in your profile properly please mate ..

 

And onto your problem .. As you will find, there are multiple threads on the forum regarding the "two stage vtec", "two step" whatever or however you want to call it .. The vtec is engaged at 4500 rpm - this is the actual engine changing its characteristics (cam duration) and this is why you can still hear it .. The second stage, is the butterflies on the inlet manifold opening to 100% at 5800rpm ..

 

The reason this sounds has probably gone is the noise of the exhaust ! lol .. Get a decent induction kit on there and it'll probably return.. Having said that, I have a 4-1 straight through 2.25" system and not a fancy intake (just 3" piping and cone) and I still hear mine without any issues ..

 

And lastly, no, you don't need to worry about any sensor issues.. The standard cat never had one .. Just need to find a friendly MOT'er..

 

Also, might be worth resetting your ECU after this work .. Allow it to calibrate itself again .. If you don't know how, have a search, there are numerous threads ..

[Guest Guest]

Thats great info Grant thanks very much for the help! I followed a few of the "2 stage" threads but my main concern was about the sensors. I'll search for the reset ecu threads too and complete my profile as I'm sure this forum will become a regular stop off for me!

 

Thanks again Grant!

[Krzys]

Ok ...

 

Firstly, you are right, here is all things civic (of the M variety) Secondly, can you fill in your profile properly please mate ..

 

 

It's guest dude, not sure it's the same as signed up memebers

 

But as Grant said, lambda sensor is in the manifold and not the cat so nothing to worry about on that front, if you go for something like Tegiwa's carbon intake you'll have plenty to listen to up front! 

[Grant]

It's guest dude, not sure it's the same as signed up memebers

 

But as Grant said, lambda sensor is in the manifold and not the cat so nothing to worry about on that front, if you go for something like Tegiwa's carbon intake you'll have plenty to listen to up front! 

Yeah noticed after I'd written it, couldn't be bothered to edit!

 

 

Thats great info Grant thanks very much for the help! I followed a few of the "2 stage" threads but my main concern was about the sensors. I'll search for the reset ecu threads too and complete my profile as I'm sure this forum will become a regular stop off for me!

 

Thanks again Grant!

 

 

No problem mate .. Hope to see you signed up !

[Dave]

Yeah, as Grant says, the exhaust noise will be drowning out the roar you got from the butterflies opening. Any decent induction kit will return the induction roar, as this is where the actual second sound comes from, the air intake. Get some photos of your MB up when you sign up mate, we all love to see photos of members cars!

[h4mza]

I was told not having a sensor plug on decat gives poor fuel economy, right or wrong?

[Grant]

I was told not having a sensor plug on decat gives poor fuel economy, right or wrong?

We're talking about the B18c4 here mate. Some of the other lesser engines do have their Lamba sensor in the cat. And no, it probably wouldn't help.

[Krzys]

I was told not having a sensor plug on decat gives poor fuel economy, right or wrong?

We're talking about the B18c4 here mate. Some of the other lesser engines do have their Lamba sensor in the cat. And no, it probably wouldn't help.

x2 MB6/MC2 doesn't have anything on the cat to begin with.

[DeLaSoul]

I was told not having a sensor plug on decat gives poor fuel economy, right or wrong?

It won't help as the ecu can't confirm if it is running at the correct air to fuel ratio, therefore it plays safe and runs slightly rich to protect the engine hence slightly lower fuel economy.