329 replies to this topic

[Nev]

Climey, that second video sounds like the turbo is surging badly (ie semi stalling) during acceleration which would indicate that there is something badly wrong with the relationship between turbo and engine . If it is that, the situation is caused by the turbo compressor supplying too much boosted air for the engine to consume, which causes the boost to reverse flow and stall the the compressor. On a compressor map this is identified by falling off the left of the graph, due to poor matching of turbo to engine.

Edited by Nev, 23 October 2012 - 08:56 AM.

[GeorgeBC]

Its almost identical to how mine sounds since i fitted the Apexi cone filter.

[JohnTurbo]

I always wonder what tfsi stands for...my best guess is Tutbo-F%#kin'-Super-Injection

[JG]

Turbo fuel stratified injection

[JohnTurbo]

I was 50% there! - Plus mine sounds better down the pub.

[CocoPops]

http://en.wikipedia....ified_injection

[JG]

Its baiscly diesel technology applied to a petrol engine. So you have a similar (though lubrication differs significatly) high pressure pump which injects the fuel in much more controlled way directly into the top of the cyl. Its best incarnation in my view is the 1.4TSI (SC+Turbo) lovely engine.

[Paul@PSR]

HI Guys FYI- Project hasn't fallen apart... S1 was done and this is an S2 which has been delayed by many things such as opening another unit (just to house these projects) losing a member of staff and just being booked up for up to a month at a time. We are not doing a DSG though, thats not us. We also have a supercherged 1zz, duratec into s1 amongst day to day work such as Aston Martin v12 rebuild, Porshce 964 engine rebuild and today we have a ferrari F430 clutch so as you can see snowed under doesn't come close ...

[SteveA]

Lazy.

[JohnTurbo]

...Er....Power-Super-Race?

[techieboy]

HI Guys FYI- Project hasn't fallen apart... S1 was done and this is an S2 which has been delayed by many things such as opening another unit (just to house these projects) losing a member of staff and just being booked up for up to a month at a time. We are not doing a DSG though, thats not us. We also have a supercherged 1zz, duratec into s1 amongst day to day work such as Aston Martin v12 rebuild, Porshce 964 engine rebuild and today we have a ferrari F430 clutch so as you can see snowed under doesn't come close ...

Nice to be busy on some exotica, instead of a bunch of plastic skips, though.

[Paul@PSR]

Plenty of skips here aswell DB9 engine nearly stripped down... images for facebook possibly

[Bumblebee]

Climey, that second video sounds like the turbo is surging badly (ie semi stalling) during acceleration which would indicate that there is something badly wrong with the relationship between turbo and engine .

If it is that, the situation is caused by the turbo compressor supplying too much boosted air for the engine to consume, which causes the boost to reverse flow and stall the the compressor. On a compressor map this is identified by falling off the left of the graph, due to poor matching of turbo to engine.

Are you referring to those fluttering noises?

[Nev]

Climey, that second video sounds like the turbo is surging badly (ie semi stalling) during acceleration which would indicate that there is something badly wrong with the relationship between turbo and engine .

If it is that, the situation is caused by the turbo compressor supplying too much boosted air for the engine to consume, which causes the boost to reverse flow and stall the the compressor. On a compressor map this is identified by falling off the left of the graph, due to poor matching of turbo to engine.

Are you referring to those fluttering noises?

Yep. I can't be certain however, just from listening to the video only. If the owner were to tell me the boost gauge flickers back and forth during acceleration that would confirm it to me. It is also possible that the sound is caused by his wastegate incorrectly opening and closing rapidly during acceleration. As I said, hard for me to know remotely.

I've seen other videos of cars doing this before. Unfortunately, you can't just strap any turbo onto a car and hope for the best, the turbo hot and cold side has to be mathematically matched to the engine. If I am right, that guy will find his turbo's thrust bearing expires rather quickly and also his car will not accelerate as fast as it could with a better matched unit.

I spent lots of hours working this stuff out for my project (and got some confirmation from Winstar as well) before I bought my turbo.

[luke.]

I am pretty certain that's an oe turbo nev so would this still be the case? Interesting stuff which is waaaay out of my depth If that affects the performance then imagine what it could do fully functional. That's like 30-110 all in fourth gear in like 7 seconds

[Zoobeef]

The sound on that one is quite possible just the dump valve designed to sound like that

[Nev]

The sound on that one is quite possible just the dump valve designed to sound like that

Yep, possibly the bypass/dump valve, which should not be operating on WOT as it is the wastegate that should regulate boost on WOT. The bypass/dump valve is only meant to operate when you come of the throttle, and if it does operate it should do so smoooothly or it can really unsettle the car.

This is all speculation BTW, based on a single sound clip from a single video. Please don't take it as gospel. I am sure Duncan will know whats going on and whether things are working correctly.

Edited by Nev, 23 October 2012 - 05:15 PM.

[Zoobeef]

On the clip I think he is revving and coming off on purpose to make the sound to stick it on tube of the you

[Bumblebee]

Its almost identical to how mine sounds since i fitted the
Apexi cone filter.

Interesting...as Mine doesn't sound like that

Edited by Aimy, 23 October 2012 - 05:29 PM.

[GeorgeBC]

Its almost identical to how mine sounds since i fitted the
Apexi cone filter.

Interesting...as Mine doesn't sound like that

Have you got an external recirc/dump valve? The bloke in the video is on and off boost and when i come off boost it makes the chavvy boost dump noise. Didnt do it with my standard airbox and thats the only thing to change.

My boost gauge doesnt flicker.