I ran my 12A without any exhaust except for the manifold, and holy cow was I not expecting anything like that.

Is it normal they sound disgustingly loud and make awful noises without an exhaust system? I thought I blew something up.

I'm aware that engines need back-pressure to run properly, but that was certainly not what I was expecting. Also revs would not build past 4000 and I was too scared to push it harder anyways.

thanks,
Josh

 

what exactly were you expecting?

all engines are disgustingly loud without mufflers - reciprocating or rotary. uncork that 855 sometime ... without the turbo ... and see how sexy you think it is then. oh and if you develop a liking for that shattered skull feeling with bloody ears to boot, then treat yourself to a bridgeport with an open header.

anyway, they don't need backpressure to run properly. however, about that 4000 RPM ceiling, was it doing that before you removed the exhaust or only after? something is clearly wrong, so give us some information on it.

 

I guess I'll just put the exhaust back on and see what happens.. It was running fine before the removal, all I did was install a new clutch and that's why the exhaust was off.

I ran it without exhaust for the sake of, why the hell not. I can't really stress how loud the pops and bangs were, is that simply because carburetor?

Idle is really rough and really low without exhaust, before it was ok, maybe a bit sputtery but nothing major.

 

carburetor has little to do with it. think of it this way, whether carb or EFI, fuel is fuel and you're essentially hearing 6 fuel-laced bombs every revolution (inconceivably little amount of time between them). for the most part bombs are loud. no?

check and see if you have interfered with the secondaries' function in any of the work you performed.

 

So that being said, what am I looking for and how do I test the secondaries function?


Also forgot to mention I removed the emissions pump hose that pumps into the cat.

 

Put the exhaust Back on,then take it from there.
You said it was running fine then so why not bring it back to normal?
Having no exhaust,the car has a different 'parameter" of what it was tuned for before(back pressure,exhaust restriction)
Having the cat removed you may have to fiddle a bit with the carb but it is a hell of a lot better than being a nuisance to people buy having NO exhaust.,and having to figure out "why it wont run right" when the engine has absolutely zero back pressure.

 

The only problem there is that I had to cut one of the bolts off.

Will definitely put the exhaust back on, if problem persists I'll be back. I guess I was just wondering if it was abnormal that it won't run properly without an exhaust system.

 

So, tried to start it again, my battery is very weak, even with a strong jump I was unable to get it to fire...

Would it be safe to assume that when I removed the starter and re-installed it I may have made the already weak/old battery cables even weaker?

I would like to install new cables and terminals all around and swap out the fusible links for those more modern style fusible links that pug in the same locations.

Probably wouldn't hurt to get new plugs/wires either.