My bongo is making a hisssing type noise

[expresso bongo]

I replaced my exhaust system some 18 months ago, using a kit supplied by an ebay trader. No complaints about the exhaust, but my Bongo started to do exactly this straight afterwards. I visited a very helpful turbo specialist (I thought my turbo might be rubbing) but he eliminated any cause related to the turbo and it's associated equipment. He came to the conclusion that it was an acoustical effect of the new exhaust system. I can only hear it with the window open, anyway, so if I want to know if the turbo's kicking in i just open the window.........

[mblakeway]

Hi all,

Well, there was a loose hose clip on one of the intercooler pipes. Tightned it up and off out to see what effect it has made. I am sure that this was my problem. Next issue is a small leak on the radiator base, where it locates itself. Its never ending!!

[dom_e]

Where is the intercooler located?

Ta

[missfixit70]

Behind the rad - http://www.lushprojects.com/bongopartsm ... mgno=.html

[dom_e]

Thanks A weekend project for me as well then.

[dom_e]

okay - I had a quick look under the Bongo today, but couldn't figure out which bit was the intercooler. Is it the black metal box type thing with fins (about the size of A4 paper and about 6omm thick) and two large diameter pipes coming from the top, located behind the air intake at the bottom of the bumper?

Sorry

Dom

[missfixit70]

yup

[Daniel]

Won’t be anything to do with the radiator, that’s the cooling (water) system. The turbo is run from the exhausted gasses. They flow through the blades on one side of the turbo spinning them, these are linked to another set of blades on the other side which sucks in and compress the air into the engine. The turbo will always be spinning but only really boosts (pressurises) the air when the rpm increases to a certain point or the engine is put under load (more exhaust gasses flowing through the turbo). This is why the hissing gets louder at higher rpm. Try it on a quiet road, run very light on the throttle then push it hard and you will hear the hissing increase as the turbo boosts. At cruising speed the turbo will always be boosting as the power is needed to keep the 2 tonne Bongo travelling along at those speeds. The boost pressure is controlled by the waste gate actuator. This can either be a spring regulated model but i think on the bongo it is run using a vacuum system and a spring. Basically it opens up the waste gate to release exhaust pressure once the preset boost pressure has been reached. Without this the turbo would keep boosting and it would either fail or your head gasket would go pop!

http://www.youtube.com/watch?v=U43jY0eXfWk

Good animation showing how it works. The cold air side is in blue, you can see the intercooler in the systm on that side. the hot air side is in red.

http://www.youtube.com/watch?v=HJSBx4a1NyI

Here you can see how the sound of the turbo, on a high performance engine, can be louder than the engine itself. Love them!

I can hear mine when under load and all the houses are fine. Typically the standard boost pressure on a production car running turbo is about 7psi. My mate had a Escort Cosworth heavily modded kicking out a gut renching 550bhps! The engine was totally rebuilt. Along with most of the car and was running the huge Garret T4 turbo. So much lag it wasn’t funny but once it spooled up and hit its 28lb boost it sounded as though he had a jet under the bonnet! Love turbo powered cars! My little R5GT Turbo i had as a teenager was so much fun!
Bit off topic i know

[dom_e]

Wow! That's a very useful insight Fantastic.

I checked all the hoses I could find, but found nowt wrong, so I guess it's just normal. I notice you're in Cardiff as well. Perhaps if we ever bump (not literally I'd hope!) into each, we could have a Bongo hiss comparison.

Cheers.

Dom

[lizard]

Well, after all this most helpfull and excellent advice, I thought that I would give my threehalf pence worth. I had a strange hissing noise and found that this was caused by the Misses winging about my driving.

[dom_e]

Time to change your driving habbits

I've just been cruising the members section and read up a bit more about turbos and some of the problems recounted in the top tips section.

There's oil on the big pipe (the main looking one under the passenger seat, leading into the turbo) on my Bongo. The couple who posted their experiences said that they found a loose pipe and that it looked like the engine oil had been over filled. They suggested that this had led to oil finding its way into the turbo and leaking via the loose connection - all over the big pipe.

Does this sound viable in my situation?

Something else to get checked out!

[bigdaddycain]

Won’t be anything to do with the radiator, that’s the cooling (water) system. The turbo is run from the exhausted gasses. They flow through the blades on one side of the turbo spinning them, these are linked to another set of blades on the other side which sucks in and compress the air into the engine. The turbo will always be spinning but only really boosts (pressurises) the air when the rpm increases to a certain point or the engine is put under load (more exhaust gasses flowing through the turbo). This is why the hissing gets louder at higher rpm. Try it on a quiet road, run very light on the throttle then push it hard and you will hear the hissing increase as the turbo boosts. At cruising speed the turbo will always be boosting as the power is needed to keep the 2 tonne Bongo travelling along at those speeds. The boost pressure is controlled by the waste gate actuator. This can either be a spring regulated model but i think on the bongo it is run using a vacuum system and a spring. Basically it opens up the waste gate to release exhaust pressure once the preset boost pressure has been reached. Without this the turbo would keep boosting and it would either fail or your head gasket would go pop!

http://www.youtube.com/watch?v=U43jY0eXfWk

Good animation showing how it works. The cold air side is in blue, you can see the intercooler in the systm on that side. the hot air side is in red.

http://www.youtube.com/watch?v=HJSBx4a1NyI

Here you can see how the sound of the turbo, on a high performance engine, can be louder than the engine itself. Love them!

I can hear mine when under load and all the houses are fine. Typically the standard boost pressure on a production car running turbo is about 7psi. My mate had a Escort Cosworth heavily modded kicking out a gut renching 550bhps! The engine was totally rebuilt. Along with most of the car and was running the huge Garret T4 turbo. So much lag it wasn’t funny but once it spooled up and hit its 28lb boost it sounded as though he had a jet under the bonnet! Love turbo powered cars! My little R5GT Turbo i had as a teenager was so much fun!
Bit off topic i know

Great post Daniel!

All TD bongo's Hiss/whoosh under load at 2250/2500 RPM, if they don't...then summat's up! (open passenger window to hear it more clearly)

[brorabongo]

I had a strange hissing noise and found that this was caused by the Misses winging about my driving.

Lizard, you need one of these fitted.....