Engine/Transmission (1998.5 - 2002) Turbo bark

[kccoon]

HI i have noticed over time that when i get on my throttle hard and then back out quick it does this bark stutter blow off sound thing its hard to explain the noise but im sure you know what im talking about. i know it cant be good but idk what to do about it and i have never heard another turbo do it.

Thanks in advance

 

[TBartlett1]

This is a post I wrote a while back pertaining turbo bark. It was a reply to a fellow TDR member's questions & concerns.



My 98 does the same thing and is very loud at low speeds. I have twins and an open K&N air filter so the turbo whine is very audible and will (woof, woof, woof) if I release the throttle suddenly at low speeds, let me attempt to explain. When under power and creating boost the drive pressure in the exhaust drives (spins) the exhaust turbine which in turn spins the inlet compressor. As long as these conditions are stable the exhaust drive pressure maintains the energy to turn the turbine wheel creating boost. As soon as you release the throttle no fuel equals no energy from combustion heat which means no drive pressure. In an instant (under certain circumstances) the boost pressure can exceed the drive pressure. Now the airflow (boost) which was being driven into the intake reverses because the air pump (turbo) is essentially shut off. The air flow reverses and can back flow out through the air filter. I'm not a turbo expert but I would say a steady diet of this if excessive is not good for the turbo because the turbine wheels are being slowed down extremely fast which puts excessive loads on the turbine shaft bearings and seals.

The Phatt Shaft turbos are an attempt to eliminate breakage due to this phenomenon.

There is no performance advantage to the larger turbo shaft other than increased durability in extreme situations.



The most likely reason you are just noticing it after the mods is because the air box is modified, it was designed to quiet the inlet noise from the turbo, (noise pollution).

Your signature shows that you have an ATS 5 star TC as I do. This can also contribute in the following manner. When towing you can load the engine and build boost very at low engine speeds, and when the throttle is released your ATS TC slows the engine so fast that the boost air flow reverses.

The performance mods you have, air intake system, chip and very tight TC along with towing heavy combine to make it much more noticeable.



And you are right the 3rd gens don't bark because the electronic throttle slowly ramps the fuel down rather than abruptly shutting the fuel off to control turbo bark or surge.

 

[Skydiver]

Try to ease off the throttle.

Mine would do it when towing my 12. 6K lb 5'er and I'm running all stock settings.

I asked about if would do any damage being I was still stock and the answer was YES.

 

[Joe Mc]

Stock or non-stock turbo, barking ain't good for the bearings and blades etc. Darn pop-off valves are expensive - best bet is to ease out of the go pedal.

 

[ALepley]

Although it is bad practice for a turbo. It sounds cool

 

[Joe Mc]

Although it is bad practice for a turbo. It sounds cool

Yeah, but it's all fun and game till something gets hurt $$$$

 

[ALepley]

Yeah, but it's all fun and game till something gets hurt $$$$

Thats where the saying "You pay to play" comes in. hahaha

 

[Sixpack]

I had the same problem when I installed my 35/40. I pulled the silencer ring and the bark was gone!

 

[kccoon]

i pulled the silencer ring quite awhile back but still have the same problem. ill just have to take my foot out of it slower i guess.