Smelling like ass....
 

Another emissions thread.... This has been compiled with rigorous searching, looking, asking questions, and generally sitting on the forums for about two years now.

We all know that our cars suck when it comes to emissions. California seems to be pure hell with it, while some of us are blessed with living in a state with either very little, or NO emissions testing. I am one of the latter. Now, while removing it ALL seems like the plan right now, I have read a lot of threads with people complaining about their cars smelling bad after doing so, especially with FB owners. Now, about 99% of states require visual emissions testing as well as the sniffer test, most of our cars will fail no matter what....

However, if, lets say that we only require a sniffer test, and the "Visual" does not matter...

From doing EXTENSIVE research on the forums far and wide, the only conclusion I have, is that you

A: Need a good, non rotten out catalytic converter
B: Need the air pump because it helps with one of the gasses that is in the exhaust.
C: Need a properly functioning OMP and good compression to achieve a proper fuel burn rate and not eat too much oil.


Ok, here comes another issue: A lot of FB and FC owners with no emissions, cat, or air pump complain about their car smelling really bad. And this is a VERY common occurrence as well. What do these people have in common? No cat and no air pump! So, this leads me to believe that, were I to keep these things, my car would not stink? I will get a nice aftermarket hi-flow cat if my theory is true!

Problem is that emissions usually means restricting performance.
That would be a better question?
If we were willing to take a hit in performance, I'm sure having a cat wouldn't be a problem...

Most cats, even "high flow" ones, are restrictive.
It's still going to hurt performance versus a "straight through" exhaust system.
How do you get around that?
Run a BIG )@*$%( cat...or multiple cats.
Problem is that these things cost money.
I'm trying to get a pair 'o Metalit 3" cats from Japan and run them in parallel.
One of the big rotary shops in Japan (FEED or Panspeed) did this on a "700hp" 13B turbo with good results.
Figure this would be fine for my needs which is only 500hp. :)
Metalit cats are very hard to get in the USA, and they are very expensive used even in Japan. :(


-Ted

I have a cat and my car smells. As soon as I can get it registered, that cat is freakin' gone.

Ah, the glories of no emiosions testing. 3" straight through works for me.

lol 99% of states.. at least make it 98%

Can't wait to install my RB header and Pre silencer on my NA GTUs!
Time to get high!

I've been gettin high since my t2 was stock. The guy I bought it from complained about it if he could only smell it now.

No emissions testing here either.

Get it tuned right that will help alot.

IF you happen to read grassroots motorsports, you would know that that is not quite true.

if you run a spun cat on a miata for example, then it gives you a better power band than a test pipe! Also, if you run that wierd stack exhaust that dumps right after the header, it doesnt give any more gain than a good rear exit system, just more noise, so on an NA, a high flow cat does not decrease the flow so much that it robs the car of horsepower.

You know your shit, but aftermarket catalytic converters have advanced a lot further than most people think.



So if it isnt the removal of the cats and air pump, then what causes the fumes in the passenger bay? I want to eliminate this problem if possible.

That is the reason why I said "MOST"...
If anything, the examples you have cited got lucky due to exhaust tuning.
It's just luck.
The combination of parts just so happen to hit a "sweet spot" for power, and that's why the results came out like that...

I'm talking about turbos, and almost always any cat is a restriction which is going to hurt power over a straight pipe.
Normally aspirated exhaust tuning can get tricky, and it's not something I think about myself.
I realize that the OP could've been talking about a non-turbo application...


It's just the nature of the 13B engine.
It comes down to intake and exhaust port timing (well, mostly exhaust) and the dynamics of combustion in the 13B rotary engine...and RPM.
I mention RPM's cause after a certain RPM, the EGT's got hot enough to burn almost everything in the exhaust.
This is why you don't smell the exhaust cruising on the high at around 3kRPM...well, that and your car should be in closed-loop at around 14.7 AFR.
At lower RPM's - i.e. idle - the EGT's are just not hot enough to burn everything up.


-Ted

Tuning isn't an issue it's tune is fine, the car is naturally going to stink it's just the nature of the 13b, the stinch will always be there. I'm not complaining though the smell of exhaust fumes on a hot summer day how can ya beat that.:001_005:

Ok, gotcha! Thanks for the explanation. I never considered the EGT being an issue.

But then, dont piston cars generally have lower EGT's? So, why is this not a problem there? does in have to do with the exhaust gasses going of of a rotary at twice the speed of a piston engine?

It doesn't take that much heat to burn everything up...
Maybe around 1000F or about 600C?
Piston engines can hit those kinda of EGT's no problem.


-Ted

we have only a high flow cat on the gray one and we had no smell besides the 90w tranny oil in the floor board. (we rescued the car from abuseive owners.)

If it's bad enough to get you high like you said i'd say something is a little off, mine leaks at the gasket to the engine and it's not that bad.

We're speaking about at idle right?