Blowback?? I'm assuming your talking about the popping noise some cars have on the over-run.
It is caused by the engine running too rich and excess fuel is ignited in the exhaust.
I always thought only petrols did this as diesel requires heat and pressure to ignite
It is caused by the engine running too rich and excess fuel is ignited in the exhaust.
I always thought only petrols did this as diesel requires heat and pressure to ignite
cavie_toledo
Guest
I've no idea what you're talking about. The individual words are English, but put together they are gibberish.
Diesels don't backfire.
Diesels don't backfire.
cavie_toledo
Guest
u must be stupid then cause my friend took back box of his and she blowsback when he lifts of the rev!!
You can hear it with just the backbox removed, but it is far louder with the cat removed as well.
BTW, calling somebody who obviously knows far more than you do stupid only makes you look stupid yourself. Politeness costs nothing.
BTW, calling somebody who obviously knows far more than you do stupid only makes you look stupid yourself. Politeness costs nothing.
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At least the misspelling makes it easy to locate the correct clip.
That isn't backfiring, as has already been pointed out. That's the wastegate opening on the overrun. Like I said, diesels don't backfire.
Something fishy about this though. GT TDI has a 130bhp PD engine and variable-vane turbo, no wastegate. So either that's an aftermarket turbo or a TDI 90 engine.
Anyway it explains your problem. No wastegate.
That isn't backfiring, as has already been pointed out. That's the wastegate opening on the overrun. Like I said, diesels don't backfire.
Something fishy about this though. GT TDI has a 130bhp PD engine and variable-vane turbo, no wastegate. So either that's an aftermarket turbo or a TDI 90 engine.
Anyway it explains your problem. No wastegate.
The early GT TDI Golfs had the 110bhp engine, and some continental spec cars came with a wastegated turbo rather than a VNT. Not in this country though as standard, but the Youtube clip is an Italian car.
Toledo_130
Guest
it obviously has nothing to do with the wastegate as the 90 - 150 engine all make a loud poooow noise with the backbox n cat removed.... 90 having a wastegate, 100 110 115 130 150 all having a vnt
iirc it is something to do with the turbo turbine spining the opposite direction when you let off the revs.. could be wrong.lol
il have a wee search on uk-mkivs again
iirc it is something to do with the turbo turbine spining the opposite direction when you let off the revs.. could be wrong.lol
il have a wee search on uk-mkivs again
I thought the wastegate (or its equivalent device) is designed to stop the turbo spinning in the opposite direction? The sudden drop in pressure when changing direction can cause a reverse pressure flow into the turbo, but in general if this pressure is allowed to progress to the turbo, you either have massive lag as the turbo spins up again, or in the worst case the turbo will eventually self destruct from the forces.
I may be wrong though, I'm desperately trying to remember my turbocharger theory!!
Edit: Oops, I thought I'd got it wrong. The wastegate simply controls the amount of boost pressure to stop the turbo from spinning beyond it's limits. It's the dump valve that stops the air pressure from killing the turbo...
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Interesting. Is that all diesels or just the ones SEAT use? What do they use to dispose of the excess back pressure, or is that more a petrol engine characteristic?
infinityraver
Guest
poww
Most toledos ive ever seen with straight throughs poww. Its class and im considering it. You get the same effect taking the clip out in the middle the exhaust. I think its something to do with the drop in pressure and the turbo when you change gear etc
Most toledos ive ever seen with straight throughs poww. Its class and im considering it. You get the same effect taking the clip out in the middle the exhaust. I think its something to do with the drop in pressure and the turbo when you change gear etc
Slimy wrote
Interesting. Is that all diesels or just the ones SEAT use? What do they use to dispose of the excess back pressure, or is that more a petrol engine characteristic?
http://www.seatcupra.net/forums/showthread.php?t=235874
Interesting. Is that all diesels or just the ones SEAT use? What do they use to dispose of the excess back pressure, or is that more a petrol engine characteristic?
http://www.seatcupra.net/forums/showthread.php?t=235874
Thinking more about this fluttering noise on the overrun, the wastegate is actuated by overpressure in the exhaust manifold, and there shouldn't be overpressure on the overrun. Although the ECU could be opening the wastegate to slow the turbo down.
What happens when you lift your foot off on a TDI engine is that fuel is cut off from the injectors, and the engine becomes an air pump. This will reduce the pressure in the exhaust manifold as there are no hot combustion products. So, maybe with the silencers and catalyst removed, the noise that can be heard is the difference between an engine producing power, with fuel going bang in the cylinders, and an engine in engine-braking mode, with no bangs in the cylinders, just flutter as the air is pushed out of the exhuast valves. Mind you, that still has to make it through the exhaust turbine, which is going to damp it down.
What happens when you lift your foot off on a TDI engine is that fuel is cut off from the injectors, and the engine becomes an air pump. This will reduce the pressure in the exhaust manifold as there are no hot combustion products. So, maybe with the silencers and catalyst removed, the noise that can be heard is the difference between an engine producing power, with fuel going bang in the cylinders, and an engine in engine-braking mode, with no bangs in the cylinders, just flutter as the air is pushed out of the exhuast valves. Mind you, that still has to make it through the exhaust turbine, which is going to damp it down.
Slimy wrote
Interesting. Is that all diesels or just the ones SEAT use? What do they use to dispose of the excess back pressure, or is that more a petrol engine characteristic?
http://www.seatcupra.net/forums/showthread.php?t=235874
You learn something new every day! I knew diesels didn't have a throttle as such, but I didn't understand how that affected the turbo.
Cheers dude!
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