Found a pipe going into my cat

[jimmydanny]

Might this be from the wastegate? It is going from the turbo area..-ish? And goes straight through my cat, so I guess it is used both as a way to get rid of the wastegate exhaust as well as heating up the cat to working temperature.

Can someone confirm this? Also, I want to replace my cat as I got an 88, and in Norway there is no law on cats prior to 89. That is, weld a straight pipe instead of the cat.

In that case, what should I do with the wastegate return? Can I make a screamer out of the internal wastegate, or is it only on external that is doable?

NB! Before any trolls answer, cat is not the animal, it is the catalytic converter!

Jim

[TiddlesRX7]

The pipe will be the one from the air pump. Its there to help the emissions. The air pump runs fresh air through it into the CAT to dilute the mixture coming out the back of the car as such. If the car has had the air pump removed then there is no need for the pipe. Also removing the CAT is a basic mod and a replacement pipe can be bought from various places, or you could make your own or have one made for you. Just be careful when you free up the exhaust flow as you will start getting boost creep and you may hit fuel cut also.

[jimmydanny]

Btw, jfyi, it is just to test how it would sound like. But I still dunno if that pipe is for that or what it really is used for.

[jimmydanny]

Ah okay. Thing is, I am not sure if I am going to remove the cat (as it is empty inside already), or if it is worth the 10£ it costs for the pipe and welding wire (thingy).

Also, I find it weird that the pipe goes into the turbo, as the air pump isnt in there, it is straight infront of the turbo almost, right?

[TiddlesRX7]

Does it definately go into the turbo? The airpump pipe is around 12mm diameter. It goes right up beside the turbo from memory.


If your pipe goes into the turbo then you may have a modefied wastegate. Something I\'d be interested in looking at actually as when I had mine apart I thought about modding it to support an external wastegate. I think you may need to get some pictures of it uploaded so we can all have a look.

[Prof]

Pics will help, but tiddles is right, that pipe into the cat would normally come out of the lower inlet manifold - just under the top water pipe for the stock turbo.

[jimmydanny]

Might be that I was wrong, as it is pretty dark here north of the Polar Circle But okay then, is there a point in having that pipe? I mean, it helps on the emissions, right? Well... It is an pre-89, so cat is not needed, emissions are just tested for fun so to speak.

[TiddlesRX7]

Have a look at this thread it might give you an idea.
http://www.mazdarotaryclub.com/forums/showthread.php?t=66531&highlight=air+pump+removal

[Prof]

Might be that I was wrong, as it is pretty dark here north of the Polar Circle But okay then, is there a point in having that pipe? I mean, it helps on the emissions, right? Well... It is an pre-89, so cat is not needed, emissions are just tested for fun so to speak.

If you\'re CAT is empty, then this pipe isn\'t doing much for sure  It feeds air into the CAT at startup and certain times during engine running - the idea being to provide air source for the catalyst to quickly reach operating temperature and convert CO and unburnt hydrocarbons to CO2 and water.  If the mesh isn\'t in the CAT anymore, then it\'s just a hollow box, and although some exhaust gas will convert in the pipe, it\'s more likely the air will just pass through the exhaust and give you nice fire show out the back

[jimmydanny]

Fireshow, yes Hehe, put a piston at the rear of the exhaust, attach a shaft, and I got two engines. That tells you a bit about how much air/fuel is ignited there

Anyhow, there is no easier way of removing that airtube? I mean, I can just let it be as it is, not connected to anything? I will lose what, 0.3HP on that, and instead of buying new belts and all that for 100£ (yeah, it is expensive to get stuff from US to Norway)

I thought my car was running a bit rich, but if that airpipe is so significant, that might be it. My exhaust sounds a bit.. thick/fat too, might be because of that then?