[ellis]

if i disconnect my exhaust halfway after the cat converter and before muffler can this couse any engine damage?

[SuziBlu]

No, but why, very noisy, and also a fire hazard.

Not to mention you can get busted big time for that.

[tanshi]

cos he is from Gimpy nuf said

[ck13488]

ellis wrote:

if i disconnect my exhaust halfway after the cat converter and before muffler can this couse any engine damage?

your car could catch on fire and that would probably damage your engine

if you really need to just unbolt the muffler and take it to an exhaust shop and tell them you want it as a straight pipe because its for a comp car or something

[MacDaddy]

SuziBlu wrote:

No, but why, very noisy, and also a fire hazard.

Not to mention you can get busted big time for that.

X 2
Plus there will be a noticeable drop in engine power making it that short

[Llewellyn92]

MacBear wrote:

SuziBlu wrote:

No, but why, very noisy, and also a fire hazard.

Not to mention you can get busted big time for that.

X 2
Plus there will be a noticeable drop in engine power making it that short

here we go again people, im not sure there would be a loss of power, theoretically without a muffler there is less resistance and the motor should run more efficiently. I have always been under the impression that the most power would be had from a tuned set of extractors venting almost straight to atmosphere? this way the exhaust gasses dont have time to slow down and back pressure is kept to a minimum ( mind you not exactly legal ), Anyone got any ideas on the matter? im interested on what others thoughts are

[losfer]

the pulses need somewhere to meet and cause an equal backpressure on all the cylinders. if you dont have enough backpressure you will be pushing some of the intake charge out the exhaust when the valves overlap (the valves are both open at some part of the engine cycle) which will reduce the efficiency of the combustion cycle, too much backpressure and you lose power from a restriction in the system . theres plenty of subjects on this if you look..

[JrZook]

Ha this is gonna be another epic thread!!

One Q for the OP: Why the hell would you want to drop the muffler? Yes it will be noisy as hell woooooooooooo you going for playing a role in the next fast and furious

But for an answer to your question, no engine damage will be done. Just hearing issues.

Tanshi: agreed

[Gwagensteve]

I'm reluctant to post in this thread, but here goes.

A) I'm not advocating it, and it will be loud, but not, perhaps, as loud as you might think. More importantly, it won't just be loud, it will sound terrible There is no good reason to do this except in emergency.

B) Those claiming that removing the muffler will result in a loss of power through reduced backpressure might be sort of right, but they need to understand where the restriction is in the exhaust for the purposes of scavenging, which is where the "lost power" theory comes from.

Scavenging is all over at the collector (so, in the case of a sierra, where the exhaust transitions from cast manifold to the tubular down pipe)

That's why it's true that theoretically the best power is made with a set of tuned length extractors and no backpressure beyond that point- the scavenging all done by the collector, not the tube after to collector.

I'd be surprised if after 5 feet of 1.5" exhaust tube that there's much effect from a muffler. There's plenty of backpressure in the (poorly designed) stock manifold and the frictional loss on the 5 feet of tube, where the exhaust is hot and flowing fast, would exceed the minimal restriction in the muffler.

Lets also consider that that we're only talking about 47Kw and 100Nm best case, and a change of 10% is about the "seat of the pants" detectable threshold. Lots of the performance gains are aural when talking about exhaust and performance.

Steve.

[christover1]

Some mufflers act as spark arresters, too.
Not sure if a CAT can arrest sparks.
So if driving in a fire prone area,
I'm guessing it may not be wise to remove a muffler

[whincup]

losfer wrote:

the pulses need somewhere to meet and cause an equal backpressure on all the cylinders.

would zero backpressure on all cylinders count as equal??

[christover1]

I admit to knowing nothing about the science of airflow, combustion and related issues.
But having driven many cars with and without exhausts, and with and without complete or good quality exhaust systems, I know a properley made exhaust system wins in all ways.
Except maybe for the psychological benefits of sound must equal power.

May explain why I'm deaf now lol

[MacDaddy]

Llewellyn92 wrote:

MacBear wrote:

SuziBlu wrote:

No, but why, very noisy, and also a fire hazard.

Not to mention you can get busted big time for that.

X 2
Plus there will be a noticeable drop in engine power making it that short

here we go again people, im not sure there would be a loss of power, theoretically without a muffler there is less resistance and the motor should run more efficiently. I have always been under the impression that the most power would be had from a tuned set of extractors venting almost straight to atmosphere? this way the exhaust gasses dont have time to slow down and back pressure is kept to a minimum ( mind you not exactly legal ), Anyone got any ideas on the matter? im interested on what others thoughts are

Yep here we go again... he he... Back pressure is a 100% myth, perpetrated by those in the industry... its about restriction and the scavenging effect... if you loose to much restriction, you loose scavenging, and get exhaust gases sucked back into the engine... the only cars i know off with that short unrestricted exhaust, are drag and racing cars, because they operate at very high RPM's 95% of the time, it isnt very efficient or practical for a daily drive, and you will notice a power loss at low RPM, and will use more fuel...

Where is Royce, he is full bottle on this, there is a very good thread about this somewhere, i cant find the exact one, but here are a couple -
Back Pressure -
http://www.auszookers.com/index.php?nam ... ing+effect
Exhaust Size
http://www.auszookers.com/index.php?nam ... t&start=60