Outer Limits 4x4 Board

So what make a turbo noisy (whooshing whine) and can anything be done to quiet it down a bit?

I test drove a number of cars recently and was surprised at the different turbo noises they made.

My new TD6 Patrol has quite a loud turbo, which I dont mind, but I was wondering what makes them sound like they do.

I imagine the vanes on the turbo get worn/pitted over time so is this the reason?

I dont think there is anything wrong with mine, it pulls hard but its turbo certainly sounds like a big truck.

i found fitting a biggest exhaust cuts out a bit of the whine, basicly its doing less rpm to make the same boost.
the other is the oil used. it generally gets a bit noisier towards oil change time.
also intake tubing can make a huge difference in noise level. especially so with pod filters fitted, minimal increase in power but huge increase in noise !

a turbo is usually doing well over 30 000 rpm so it is always gunna be noisy like tweak said intake has a lot to do with it snorkels usually make the turbo seem louder

How do you figure a bigger exhaust makes the turbo spin less to make the same boost, the bigger the exhaust the less restriction, the faster the turbo will spool, and will ussually make 1-2psi more obviously to big is no good. Air flow is relevent to rpm and boost, anyway, as you said intake has alot to do with it.

berad wrote:how do you figure a bigger exhaust makes the turbo spin less to make the same boost. air flow is relevent to rpm and boost.

motor does less work to make the same power = less exhaust gas= lower turbo speed.

less exhaust gas = lower boost.

As im sure you know a turbo is just a big air pump run from the exhaust gases, if theres not as much exhaust gas coming out, then the "pump" will not be spinning as fast therefore pushing less air into the engine, which will not make the same power.

It doesnt matter wheather you have a 2 inch or 10inch exhaust, the exhaust gas still has to flow through the exhaust wheel in the turbo. It still has to suck in (x) amount of air to make the (x) boost at (x) rpm, its the size of the exhaust that lets the air get out faster enabling faster spool and higher boost pressures.

grazza wrote:So what make a turbo noisy (whooshing whine) and can anything be done to quiet it down a bit?

I test drove a number of cars recently and was surprised at the different turbo noises they made.

My new TD6 Patrol has quite a loud turbo, which I dont mind, but I was wondering what makes them sound like they do.

I imagine the vanes on the turbo get worn/pitted over time so is this the reason?

I dont think there is anything wrong with mine, it pulls hard but its turbo certainly sounds like a big truck.

It's actually the induction noise.

Not much you can do to make it less unless you took it out, which makes the diesel engine run slower and it'll chew up more diesel.

You could sound proof your car some more to help reduce the overall amount of noise you hear from the outside.

berad wrote:less exhaust gas = lower boost.

doh i shouldn't have said boost, i should have said power. quite right less exhaust should be less boost.
however i didn't notice any drop in boost with the exhaust upgrade, just less turbo noise at cruise. my boost guage isn't exactly supper accurate, also the boost varies a fair bit at cruise (from 5-10psi).

You wont notice any less boost, it should spool faster than a factory sized exhaust and if anything have slightly more boost.


Good luck.

Will let y'all know if the new exhaust and dump pipe make a difference. Booked in on Wednesday.

grazza wrote:So what make a turbo noisy (whooshing whine) and can anything be done to quiet it down a bit?

I test drove a number of cars recently and was surprised at the different turbo noises they made.

My new TD6 Patrol has quite a loud turbo, which I dont mind, but I was wondering what makes them sound like they do.

I imagine the vanes on the turbo get worn/pitted over time so is this the reason?

I dont think there is anything wrong with mine, it pulls hard but its turbo certainly sounds like a big truck.

i think they put little birds in there so think about the poor buggers the next time you use the right pedal a bit to much.

are the birds good looking? i

I've never heard of a turbo being too loud

People usually want to make them whine more, not less

The intake system has the biggest effect.
Especially rubber/plastic hoses vs steel/aluminium pipe.

i supose alli would be best for induction? being smoother and able to cool quicker? does the alli induction make it louder?

crack wrote:i supose alli would be best for induction? being smoother and able to cool quicker? does the alli induction make it louder?

Yeah, metal is heaps louder than plastic or rubber.

im with hotfourok on this one, i love hearing the turbo spooling up on mine..

If i could make it louder i would lol

I am not saying I dont like it, I am just curious as to what is actually causing one turbo to be noiser than another, and why a turbo would get noiser as it got older.

I hypothesised that it was because the vanes on the turbo were gradually loosing their smoothness or maybe aerodynamic-ness

Maybe its dust buildup in the pipework?

The different types of pipework sounds right.

ADEM wrote:im with hotfourok on this one, i love hearing the turbo spooling up on mine..

If i could make it louder i would lol

fit a 4" stainless snorkle you will then hear the turbo alot more... however saying that it gets really annoying with the windows down...

ADEM wrote:im with hotfourok on this one, i love hearing the turbo spooling up on mine..

If i could make it louder i would lol

Yeah, a 3" stanless steel snorkel sure helps And the 2.5" exhaust just to add a bit more.

Grazza - what you need is a thing called a dose pipe......... search it on youtube.







BTW, Im joking

Jaffa wrote:Grazza - what you need is a thing called a dose pipe......... search it on youtube.

BTW, Im joking

i'm still trying to get my head around the 'dose' thing. it just doesn't make sence.

Picked up the Patrol after a 3" exhaust and dump pipe yesterday arvo.
The turbo does not sound any different but it feels like a little more power. Hard to say exactly without a before and after dyno.

Getting the injector pump tweaked next.