exhaust flow

[beechfront]

recently fitted a new can muffler to my new XS.

the can muffler slipped perfectly INSIDE of my 4-1 header. is this going to be a problem? i wouldn't think it should make any noticeable difference.

my concern is the exaust flow will be disturbed when it reaches this point.

[Dennyz]

The flow of the can will have more effect on flow than the inside slip fit. Send us a picture of your custom exhaust.

[beechfront]

ok thanks -


will hopefully get a picture soon.

[beechfront]

as far as power goes - i can't really tell any difference between open exhaust and this new can muffler.

EXCEPT - around 5-6000 there is a dead spot now that wasn't there with the open exhaust.


I don't know much at all about exhaust - but one thing i thought that might be a problem is when i pieced those pipes together i used some exhaust sealant that i got at the local parts store. now thinking back - the way i applied it, when i slid the pipes togetheer that goop proboblay bunched up inside the pipe (it's a really tight fit). This probably sounds pretty dumb - but could that accumulated goop be causing me problems?


The dead spot is quite noticeable and i'd like to get rid of it if possible.

thanks a ton for any advice.

[skids]

One of two things is going on, I believe.

1. If the dead spot is occurring only between 5K and 6K, but is otherwize strong with torque through the rest of the range, then there is some interferring resonance. This is caused by either exhaust leaks or by a system that is not suitable for the engine. It can cause "anti scavenging" at a given range. This happens with open exhaust also and can happen when OEM muffler have rotten-out baffles or cracks at the header transitions.

2. If the torque is weak above that range as well, the main jets are too small and perhaps the jet needle is too low in the nozzle.

I seriously doubt that an adhesive obstruction is going to give you problems as you described.

Originally posted by beechfront
as far as power goes - i can't really tell any difference between open exhaust and this new can muffler.

EXCEPT - around 5-6000 there is a dead spot now that wasn't there with the open exhaust.


I don't know much at all about exhaust - but one thing i thought that might be a problem is when i pieced those pipes together i used some exhaust sealant that i got at the local parts store. now thinking back - the way i applied it, when i slid the pipes togetheer that goop proboblay bunched up inside the pipe (it's a really tight fit). This probably sounds pretty dumb - but could that accumulated goop be causing me problems?


The dead spot is quite noticeable and i'd like to get rid of it if possible.

thanks a ton for any advice.

[beechfront]

hey skids thanks for the advice.


1 - first (easiest) thing i am going to check for is exhaust leak. I thought i had the joint sealed well, but perhaps not. I also may be do for new exhaust gaskets (though i did not have this problem with the open exhaust).

if it is in fact a problem with "the system" then I am just going to have to live with it.

2 - I don't think jetting is the problem. I re-jetted with open exhaust. running 2 sizes up on mains, 1 size on pilots.



also - since putting this can on, i have also noticed what kindof sounds like an electrical arc coming from the right side. this only occurs at low rpms and under heavy throttle though. probably not related, but just thought i would throw that out there too.

[skids]

Hmmm, I had a header pipe gasket leak once that sounded like a "tick-tick-tick." You know, you might want to track that noise down, fix it and then color some clean spark plugs in the rpm range that is giving you troubles.

Originally posted by beechfront
hey skids thanks for the advice.

also - since putting this can on, i have also noticed what kindof sounds like an electrical arc coming from the right side. this only occurs at low rpms and under heavy throttle though. probably not related, but just thought i would throw that out there too.