Audi A6 Avant 2.5 V6 TDI Quattro

[Mikkijayne]

Something in the reign of 46mm can be fitted inside the stock turbine housing.

I was wondering about that, using my Fiat turbine (~46mm) in the stock housing, but I couldn't find anyone who could do the machining.

Would that be a better idea than using the larger exhaust housing?

 

[fjtwelve]

Turbodynamics will do one off bespoke jobs and they are in Dorset http://www.turbodynamics.co.uk/map.htm not a million miles away from you

 

[Mikkijayne]

Thanks ^

Another question: has anyone done any exhaust manifold mods to this engine? Looking at the stock system it seems to be very restrictive with a lot of changes in diameter, especially round the Y piece that the turbo sits on.

I'm wondering whether there would be any worthwhile benefit from making the whole lot a bit larger and in stainless? Or possibly just making the Y-piece and manifold connectors?

 

[fjtwelve]

Extract from Turbodynamics spec sheet for the hybrid:

VAG – 180 BHP

Hybrid Turbochargers



Garrett Turbochargers – Part No 454135-0010 – Aircooled

VAG Part No. – 059145701S - 2003->

APLICATION : Audi A4/A6/A8 Vw 2.5/ 2.8TDI - 180BHP​

​

Stage1

​

MD438

​

Brief Specifications: -

Stage 1 – MD438

Hi flow GT20 compressor wheel, cnc machined compressor housing, 360 degree thrust bearing, cut back turbine blades, lightening of turbine wheel for faster ‘spool up’, modified V.N.T. turbine housing, uprated turbine seals. Other ‘blueprinting’ modifications. APPROX 280-300 BHP

Please Note: This application needs exact engine management settings, up-rated injectors, free flow exhaust system to achieve these horsepower figures.

I have no plans to mod the exhaust at present but wasn't aspiring to 300hp, anything over 250 would be good.

 

[hatemi]

Lightened turbine wheel... 300hp... I realy doubt it even if you remove some of the blades that the turbine will flow that much.

 

[majesty78]

Thats all UK bhp....take away at least 10% (of bhp numbers, not of turbine wheel*g*) and you come near truth....

 

[LTR]

I've just tried on a dyno the A6 V6 2.5TDI with stock engine, but Hybrid turbo made to stock housing, cummins nozzles, quattro 180hp new pump and big exhaust. Boost 1.8bar and EMP at 1.6bar. Gives 269hp and over 260 between 3200-4700rpm and torque @525nm.. Not enough for a front wheel driven car says the owner..

The turbo has 47mm exhaust and about 45mm compressor wheel.. Lambda is 1.12 at full acceleration.

 

[TDIfreak]

Very good numbers, LTR! This hybrid is made by Fin-Turbo, I believe?
I have to get that lambda probe very soon!!!

 

[adamss24]

I've just tried on a dyno the A6 V6 2.5TDI with stock engine, but Hybrid turbo made to stock housing, cummins nozzles, quattro 180hp new pump and big exhaust. Boost 1.8bar and EMP at 1.6bar. Gives 269hp and over 260 between 3200-4700rpm and torque @525nm.. Not enough for a front wheel driven car says the owner..

The turbo has 47mm exhaust and about 45mm compressor wheel.. Lambda is 1.12 at full acceleration.

Hi there, what cumins nozzles U used ? I wanna get a set of those cummins nozzles, do you have a rough price ? How different is the quattro 180Bhp pump to the quattro 150 Bhp pump, any ideea ? Do you have a part number for that pump as well ? Regards, Chris.

 

[Rub87]

Very good numbers, LTR! This hybrid is made by Fin-Turbo, I believe?
I have to get that lambda probe very soon!!!

Probaly, I know a guy with A4 with also hybrid from finturbo, tought it was inside of a renault turbo somehow..

 

[fjtwelve]

The car is now at Celtic to have the turbo exchanged with a Turbo Dynamics hybrid, the nozzles fitted and the computer remapped. Celtic have priced this at £1200 for everything, including what they've done to date.
Of this the exchange turbo is £795+VAT. If my turbo is goosed beyond exchanging TD had previously quoted me £1195+VAT for a new part.

If all goes OK (that'll be a first) then I get the car back Friday.

 

[LTR]

Thank you.. I'm not really happy with it..The turbo is quite good, we'll know in near future how good.

The new "big" 3 piston pump is stopping the fun to that point. It just doesn't give more fuel.

 

[fjtwelve]

Sounds just like problems that I had with missing intake levers.
Did you log the runs?

I am finding it hard to believe but when they were cleaning up the head this afternoon ready for installing the nozzles they found a broken rocker from one of the exhaust valves. Here we go again...don't know whether to be happy we found the problem or sad its broken.
The turbo has been stripped down and is ok for the rebuild. No comments about any problems with the old internals.

 

[Mikkijayne]

Mm I believe that entirely. Mine had its cams and rockers done before I got it, and by the time I stripped it down it was only running on 17 of 25 valves, with the rockers either in bits in the sump, or just lying in the heads

Did you have the lifters changed when the cams were done? I'm putting all new OE lifters in mine to be safe, as some of them were obviously damaged, and not replaced when the cams were.

 

[fjtwelve]

On close inspection we have found that the rocker is not broken, it and the little cap off the top of the tappet have popped out, hence the 2 pieces. Theories are either not properly seated when assembled or the tappet is sticking. Celtic have reseated them and installed the new nozzles, turbo due in today, we should be up and running Wednesday.
Yes all the rockers were new at Christmas

 

[fjtwelve]

Engine back together and running, currently at 1.6 bar boost and being limited by the fuel flow. Maybe i should have gone for the Race683s after all (stage 2?) but i didn't know i was going straight to the hybrid without the nozzles only stage. Still working on it, get car back tomorrow.

 

[Mikkijayne]

Hmm thats annoying. How much extra were the Race683s? Can the VP44 handle going much bigger than stock?

Any idea what power it's making so far?

 

[fjtwelve]

Very different, almost like a petrol engine. Doesn't feel very torquey at bottom end. Very deceptively fast, horribly smooth at 100mph. No shove in the back, just relentless acceleration. Nice whine whistle off turbo. Some shuddering at idle occasionally. So not 100% there. Off work Mon and Tues so will get it to dyno at some point and then go back for more work. Suspect Race683s on the way.

 

[Mikkijayne]

Interesting result. I'd love to see the dyno plots.

Let me know if you are going for the Race nozzles, because I will gladly take the others off your hands

 

[fjtwelve]

Down at the dyno today, and everything suddenly stopped. Thought we'd blown an intercooler hose. Rolled it off the dyno, checked around everywhere no obvious problem. No fault codes. Enter the AA man with his trusty can of carb cleaner, blast of that down the air intake and it started. No problem since, but we are down on power and the AFR is too high. We think there is a fuel supply problem somewhere rather than just nozzle sizes so back to Celtic tomorrow. Whether it is pumps pipes nozzles or shut off solenoids or what we don't know. Even the AA man wants me to text him to tell him what the problem was.
Still waiting for call back on Race 683s, diesel-service.nl want about E80 each.

 

[Rub87]

did you use a liftpump? these ^vp44 pumps are sensitive to overheiting/seizing when they're pushed hard and don't get enough fresch fuel.. (I read on some cumming forums)

 

[fjtwelve]

No haven't modified any pumps yet. I have found a similar problem thread here http://www.vwaudiforum.co.uk/forum/showthread.php?t=80655 so we will hunt down any faults before i start on the pumps. It could be that the VP44 is just worn out after 200k miles and needs repairing. Will post what we find

 

[Rub87]

be sure to supplie it with enough fresch fuel

 

[Mikkijayne]

It could be that the VP44 is just worn out after 200k miles and needs repairing. Will post what we find

Oooer don't say that! Mine has 240k on it, and was about the only thing that was working when the rest of it went pop I really don't want to have to rebuild it if I start tuning the new motor...

 

[shadowmaker]

Here's a 2.5TDI V6 150hp.

 

[fjtwelve]

So what did you do to it to lose so much power in 20 mins?

Sorry being a bit rude there. I wouldn't be complaining much about either of those curves. So what did you do to the engine on this one then?

 

[LTR]

I remade the engine to std spec after "little" cam problem.

Added a hybrid turbo from Fin-Turbo made to stock housing, cummings nozzles, 3" hst exhaust whole way out and tweaked the program.

The lover curve is other tuners vision about this engine. Saying it was maxed out.. still isn't..

 

[fjtwelve]

As i have a fuelling problem at the moment (not enough) am interested to know if you modified fuel system in any way other than nozzles to get more fuel in?
What size are the Cummins nozzles relative to the Bosio PP683s and Race 683s?

 

[diffas]

Like he said; stock engine with bigger nozzles.

 

[fjtwelve]

Have tested all fuel system without finding a problem. Now looking for a new/recon VP44 pump. Assume the existing one must be tired after 202000 miles.