Thread: muffler removal TDI

Originally Posted by mcrover

0 to 80kmh from the same set of lights on the same day, 2 hours different, first 12 sec with muffler and a bit ove over 10 without.

Quote it as much as you want, now it's in writting. writing

It's all about air speed with turbos and the perforated straight through pipe is desighned designed to disrupt the flow there for therefore increasing back presure pressure by slowing down the airflow and in turn it also cuts down the noise via reflection off of the turbulance turbulence within the muffler.

Take out the muffler and lower back pressure, increases airspeed passed past the inpeller impeller in the turbo thus spooling on boost faster, it doesnt doesn't increase the noise factor that much as the turbo it self itself acts as a muffler by reflection off the inpeller impeller blades.

The sound is a bit weird but can be made a bit nicer by removing the ressy as well so you get a little bark back in the note.

It isnt isn't a huge increase but it is an increase and for the price is well worth while worthwhile.

Was the "well put" comment a favourable comment about the technical explanation or a sarcastic comment about the spelling, grammar and syntax?

Originally Posted by vnx205

Was the "well put" comment a favourable comment about the technical explanation or a sarcastic comment about the spelling, grammar and syntax?

A Ron wanna be me thinks

Originally Posted by rangieman

A Ron wanna be me thinks

A Ron wannabe methinks

O lny srmat poelpe can raed tihs.

I cdnuolt blveiee taht I cluod aulaclty uesdnatnrd waht I was rdanieg. The phaonmneal pweor of the hmuan mnid, aoccdrnig to a rscheearch at Cmabrigde Uinervtisy, it deosn't mttaer in waht oredr the ltteers in a wrod are, the olny iprmoatnt tihng is taht the frist and lsat ltteer be in the rghit pclae. The rset can be a taotl mses and you can sitll raed it wouthit a porbelm. Tihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe. Amzanig huh? yaeh and I awlyas tghuhot slpeling was ipmorantt! if you can raed tihs psas it on !!

Originally Posted by rovercare

O lny srmat poelpe can raed tihs.

I cdnuolt blveiee taht I cluod aulaclty uesdnatnrd waht I was rdanieg. The phaonmneal pweor of the hmuan mnid, aoccdrnig to a rscheearch at Cmabrigde Uinervtisy, it deosn't mttaer in waht oredr the ltteers in a wrod are, the olny iprmoatnt tihng is taht the frist and lsat ltteer be in the rghit pclae. The rset can be a taotl mses and you can sitll raed it wouthit a porbelm. Tihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe. Amzanig huh? yaeh and I awlyas tghuhot slpeling was ipmorantt! if you can raed tihs psas it on !!

Good one mate

Originally Posted by mcrover

0 to 80kmh from the same set of lights on the same day, 2 hours different, first 12 sec with muffler and a bit ove 10 without.

Quote it as much as you want, now it's in writting.

I'll accept that, if it's repeatable

It's all about air speed with turbos and the perforated straight through pipe is desighned to disrupt the flow there for increasing back presure by slowing down the airflow and in turn it also cuts down the noise via reflection off the turbulance within the muffler.

actually there is naff all back pressure with a straight through perforated tube. The turbulence would be minor, as the boundary layer of gas is almost at a standstill anyway, and so velocity reduction would be minor.
Quoting from "Scientific Design of Intake and Exhaust Systems" (Smith and Morrison)

"The operating principle is that sound waves passing down the main tube penetrate into the close-packed absorbent material via perforations and are frictionally damped; the damping is usually very effective on the highest frequency waves."

Take out the muffler and lower back pressure, increases airspeed passed the inpeller in the turbo thus spooling on boost faster, it doesnt increase the noise factor that much as the turbo it self acts as a muffler by reflection off the inpeller blades.

The sound is a bit weird but can be made a bit nicer by removing the ressy as well so you get a little bark back in the note.

It isnt a huge increase but it is an increase and for the price is well worth while.

As I said, I'm surprised it does anything worthwhile, but you have the acceleration figures to back it up, so I'll accept it, but it does really surprise me.

Originally Posted by rangieman

Why do some people want a bit of paper to prove what other people have done has made a improvment , Maybe a 3" bling exhaust is too much for a Tdi , and maybe a race mechanic/engineer is too smart to realise that

'cause I don't trust 'seat of the pants' results. I've seen far too many people led up the garden path by things they 'thought' were happening but weren't.
Placebo effect.
How do all those Hiclones get sold ? There are a lot of people out there that want to believe it works, and so it does.

<edit>FWIW, when I built the 3" system it had no muffler/resonator at at all. (I don't believe in back pressure on a turbo either )
The noise was horrific. Don't let anyone tell you a 300Tdi doesn't need some sort of silencing, at least with a big bore pipe. The resonance at 100km/h was frightful (the cab became the muffler) and the sheer noise was just too much, so a resonator went on at the rear. Much better, but still tiresome on a trip.
I've also since lagged the down pipe to the back of the t/case with exhaust lagging after a post by Inc (where I questioned the long term effects, he's had it for over 80,000km, so far, so good, so I threw some old stock on mine too). Don't know if it's done anything, but it is quieter. One of the Qld exhaust places are HPC coating the dump pipe on Patrol and L/Cruiser 3" pipes after back to back dyno testing found an increase in HP/torque. It appears that by keeping the heat in the dump, gas velocity is kept up and back pressure reduced.
Hmmm, I wonder if the sheer size of the 300Tdi muffler is acting as a huge heat sink and cooling the gas too much, reducing velocity and that's where the benefit is derived....naa, but maybe, naa....</edit>

getting my muffler removed today, and will be wrapping the pipes to the back of the transfercase on this truck with header tape very shortly, now i have found where i stowed the last lot i bought :P

i do it to cut down on the mechanical noise transferred down the exhaust pipe on a diesel. well worth the fifty dollars or so the header tape sets you back IMHO.

just got mine back.

definitely a difference, spools up significantly quicker IMHO.

not a bad way of spending $40 bucks it has to be said, tho it makes the truck a marginally noisier inside but the header tape will fix that i believe...