john banks

This model number is listed as being on MY98 on. My turbo on MY00 is a 49377 04200 - rather than 49377 04100 as this picture. I think this is as close as we get.

Thought I'd put it in a new thread and let the erroneous 9B one before drop off the bottom to save confusion. This is what I am fairly sure the MY99/00 UK/Euro Scooby has, but the map is adjusted from a 15G map. The best I can find anywhere although not ideal but hopefully better than guessing!



Conduit's spreadsheet shows flows for various boost and engine speeds - you need to reduce the figure to correct for volumetric efficiency at that engine speed as well as turbo efficiency and intercooler efficiency.

[Edited by john banks - 1/30/2002 1:26:54 PM]

EvoRSX

John,
I've got maps for the td05-14g, td05H-16g, td06-16g and td06-20g if they are of any use to you.

Andy

EvoRSX

I've also found maps for the td04H 15G, td04H 18T, td04 9B and td04 13G as well.

Andy

EMS

How can I convert the flow in CFM in somewhat more common (to me) units. (metric please!)

Mark Verhoeven.

john banks

I would be interested to see if the TD04 13G map is the same as this one?

1 cubic foot per minute = 4.719 E-4 metres cubed per second

john banks

"As far as I can see is the compressor of the VF23 the same as VF24, VF28 and VF29."

Note units of cubic metres per minute.

Courtesy of Mark.

[Edited by john banks - 1/30/2002 10:11:11 PM]

Sam Elassar

max flow for a VF22 IS 470CFM
MAX FLOW FOR VF23 430 CFM

sam

john banks

470CFM = 13.3 m3/s
430CFM = 12.2 m3/s

Which matches the graphs above

john banks

TD04L is about 380 CFM max flow from our graph above.

Sam Elassar

the graphs also show that the VF22 is probably good for a 1.5bar but can be stretched to 1.7bar and the VF23 FOR 1.3bar. maybe that is way my VF23 and running the VF series above these levels risks running the blades over there design speed ? ( not a good idea).

the is obviously only the compressor map, the size of the exhaust housing and turbine housing play another big part in how the turbo spools up and behaves. that is why the VF24,28 WILL behave different to the VF23.

EvoRSX

John,
The TD04 13g map is the same as yours. I assume we both got it from the same website.

Andy

john banks

Yes probably - I cleaned up all the 3 litre twin turbo stuff off it.

AndyMc

Hi guys

Looking at the graphs I noticed the surge line.Does anybody know if any noise is produced if the surge line is crossed?.

The reason I ask is because where I work there are very large centrifugal turbo compressors which compress 3500T/D of air to 8 bar. One of them went into surge when I was standing nearby (surge protection instrumentation didn't work).The noise it made scared the witts out of me and basically sounded like 1000 artic lorries on the over-run.Apparantly surging is very bad for the blades on the turbines hence the reason why industrial compressors have electronic protection to prevent surge.

I wonder if preventing surge is part of the reason why the standard Scooby blow off valve is open under cruise conditions, allowing high flow through the turbo with a low discharge pressure.It may also be the one of the reasons the waste gate is opened by the ecu even though target boost has not been achieved?

If any of the above is true, could there be implications for people using aftermarket boost controllers and dump-valves?

Andy

john banks

That is interesting Andy. It is something I have been thinking a lot about. It seems the main worry with aftermarket manual or electronic boost controllers is the ones which have no way of "knowing" the throttle position and creating high boost on part throttle.

This would seem most dangerous if they are taking their boost measurements or targets off a sensor (MAP sensor) or supply AFTER the throttle (say wiring a Dawes off the manifold). So they try and make 15 PSI at 1/3 throttle and in a high gear there may conceivably be enough exhaust gas flow to actually produce this, resulting in much higher turbo outlet pressures and crossing the surge line because of high boost and low flow with basically high obstruction to outflow.

Hence I take my Dawes off the turbo outlet, and in my EBC design I am only using really aggressive duty cycles with large throttle openings.

Apparently a surging turbo on a car does make a noise and judders a lot.

At WOT I could make 19 PSI at 2400rpm on my car, but this seems OK from the map - just. Others said the danger area is at peak turbo efficiency but with a huge outflow obstruction - eg on a TD04L say 5000rpm full boost on 1/3 throttle.

EMS

Andy,

You can hear it also with "our" turbo's. I have a Sub with VF23 and if I lift the throttle at 5.000 rpm, you can hear the turbo is getting loud. This tells it's close to surge.

Your right also with the fact that the std. BOV opens quite early. This is a GOOD thing, people in Holland know I am very UNHAPPY whith aftermarket BOV and DV. I saw lots of them who SU**. You get massive surge with them and I saw already a VF23 explode because of that. The std. BOV on the MY99 and MY00 is VERY good and doesn't need to be replaced. (better not to do it!)

Mark Verhoeven.