exhaust option

[dub be good to me]

It looks like we all have the same setup!

My 1.8 Kjet is running extractors & a 2 inch mandrel bent system including a hotdog resonator & straight through muffler..

I'm actually looking at a quieter muffler and some sound deadening as the drone is killing my ears... around town its ok, but if I'm in the car for long trips I have to wear ear plugs

[mikinoz]

I'm actually looking at a quieter muffler and some sound deadening as the drone is killing my ears... around town its ok, but if I'm in the car for long trips I have to wear ear plugs

I thought ear plugs were standard issue with MK1 registration renewals?

[Oneofthegreats]

It looks like we all have the same setup!

My 1.8 Kjet is running extractors & a 2 inch mandrel bent system including a hotdog resonator & straight through muffler..

I'm actually looking at a quieter muffler and some sound deadening as the drone is killing my ears... around town its ok, but if I'm in the car for long trips I have to wear ear plugs

A set of 4-2-1 extractors with a 2" full system & reasonable sized hotdog & high flow muffler is the norm for a stock to mild mk1 I reckon, but can get droney at times. Especially if some of you have fancy upturned, dump pipe, curnved exhaust tips & this is where you can make the drone worse. I like to go for a as straight as possible rear section from the rear muffler to the tip to avoid this.

Above & beyond mild, you really should start looking at 2 1/4"+ high flow system.

I call mild upto 160-170hp.

There are a couple of ways you can tone it down though.

Try a rear offset high flow muffler

Try a multi chambered reverse flow rear muffler, but this can reduce flow. Not really a big deal on these size engines. But it will decrease noise substantially!

Try a new designed "proper" performance muffler like a Hooker Aero Chamber or Flowmaster 44. These are straight through, but direct the gas through various shapes to reduce noise.
They may look restrictive, but they are far from it. Several friends have the aero chambers fitted to there cars & these cars are making from 500-1200+hp without problems at all.
They maybe expensive, but are well worth it I reckon. Over kill on these vehicles as they just don't make the power to justify these mufflers

The other option is fit a turbo! haha. You not only get upto twice the power (sometimes more), but the car becomes alot quieter too! haha No more drone either!

I currently run a full mandrel system incl. a 3" dump pipe into a full 2.5" straight through system with a hotdog & high flow rear muffler.

[dub be good to me]

Especially if some of you have fancy upturned, dump pipe, curnved exhaust tips & this is where you can make the drone worse.

Very impressed, you got it in one! I've got a twin 2' DTM tip

Try a rear offset high flow muffler

Try a multi chambered reverse flow rear muffler, but this can reduce flow. Not really a big deal on these size engines. But it will decrease noise substantially!

Awesome, thanks for the info golfworx.
I'm pretty keen to get some more opinions on these types of mufflers as an exy muffler isn't in my budget at the moment.
I was about to get my mechanic to swap my straight through for either a;
-dog leg (90 degree bend in muffler) ..is this what you mean by rear offset?
OR
-a reverse flow (2 x 180 degree bends)

I know I'll probably cop a bollocking for this, but drive-ability is important to me for my daily..
I don't like the attention I get from ringin' it out... its too f#%king loud! I find I drive harder wearing earplugs cause I can't hear the damn thing

[Jarred]

Don't worry Simon, I'll forgive you that, cause you do actually drive it daily! and mod & repair it over weekends and overnight as it is your only car! big props!

I' actually really like the standard exhaust on my diesel, it isn't loud, which is something a bit different after my last two cars!

[Oneofthegreats]

Very impressed, you got it in one! I've got a twin 2' DTM tip



Awesome, thanks for the info golfworx.
I'm pretty keen to get some more opinions on these types of mufflers as an exy muffler isn't in my budget at the moment.
I was about to get my mechanic to swap my straight through for either a;
-dog leg (90 degree bend in muffler) ..is this what you mean by rear offset?
OR
-a reverse flow (2 x 180 degree bends)

I know I'll probably cop a bollocking for this, but drive-ability is important to me for my daily..
I don't like the attention I get from ringin' it out... its too f#%king loud! I find I drive harder wearing earplugs cause I can't hear the damn thing

No worry's.

I should have elaborated on the muffler design with some pictures.

High flow offset muffler meaning, entry is either viaeither the centre of the muffler or offset corner & travels across the path of the muffler body though to the other corner.
Disregard the "aero chamber". I only used it at demonstrating offset mufflers



Another offset turbo high flow muffler



Hot dog/resonator is basically a straight though piece of pipe with some packing in it & the better ones have scallop intakes to capture the gas/noise.
This one is pure straight through & they can be noisey at certain rpm!



Reversed path or multi pathed muffler, you can see how the gas has to change direction a couple of times & pass through different chambers





Hooker Aero Chamber



FlowMaster chamber design

[Oneofthegreats]

I know I'll probably cop a bollocking for this, but drive-ability is important to me for my daily..
I don't like the attention I get from ringin' it out... its too f#%king loud! I find I drive harder wearing earplugs cause I can't hear the damn thing

You won't get any crap from me going down that road.

I went back from a straight through to a reversed direction muffler & it didn't hinder performance at all on my old cranky banger engine.

It also sounded better & was quieter too which is heaps better for doing the 200km round trip to work.


I think I've still got the old entire exhaust system here too, as I don't need it anymore due to the turbo upgrade.


Changing mufflers can change the mixtures using K-Jet too. Its very sensitive to any type of change, whether its ignition timing to even cleaning/replacing the air filter.

[Peter Jones]

I' actually really like the standard exhaust on my diesel, it isn't loud, which is something a bit different after my last two cars!

Red still has the diesel exhaust which seems to work just fine with the 1800 and DGV Weber.

I'll be changing to a set of extractors, a 2' system (off Stu's old MK1)at some stage soon as rust has finally killed the 30 year old system. Not a bad lifespan for an exhaust system, but then diesels keep their pipes well oiled.

It'll be interesting to see the comparison.

On another note, I've noticed that there's two types of manifold fitted to the diesels, a single downpipe version and a dual downpipe version. The dual pipe version is basically a 4-2-1 system.

Pete

[dub be good to me]

Cool, I was worried the reverse flow would hinder the performance a little.
By the sound of it (I know ..terrible pun ) its exactly what I'm looking for, thanks!

So to summarise, the general consensus seems to be:
-Extractors (4-2-1 vs. 4-1 ?)
-2' system
-Hotdog resonator

Then in order of loudness, either a...
-a straight through muffler (loudest)
-an offset muffler
OR
-a reverse flow / multi-chambered muffler