My RS2 on the dyno...delusion?

[Rusty]

Edit as I was wrong

[porkkis]

Boost curve? Where? Am I blind?

Retarding cams gives more top end oompf. I think this is cam timing related. Try swapping back to ADU cams and have a new dyno run.

[veneto rs2]

Hi everybody!
First of all Thanks for your replys

Here is what i'll do next:

First
Check the turbo pressure and behaving by a quick connection of a turbo gauge test will be done on open road and with the motorist that made the cams timing on the passenger seat

Second
Go back on ADU stock cams timing where (as you know) means that the cams wheel position is anyway weird because it must go "off the mark"........

I must say that if i'll find any fault on the pressure.... any leak..........
i will go more to sensation/feeling on real driving rather then Dyno sentence
this because i try several RS2s of friends in the Club and i really don't quite like the "hole" they have on low revs.....

Honestly i can see that the torque curve is falling down like a stone and your experienced opinions had open my eyes even wider...

Let's say that "if" i have a turbo leakage somewhere (i'll put my money on Wastegate)
and "if" by fixing this i wil have a "steady" torque curve with a power in the end of anything between 320/340 i will be an happy boy with a nice toy

Thanks again guys!
I will keep the situation up to date

Ciao Stefano

P.S.

for S2central.net:

your advices are very precise and very useful thank you
in answer to your question:
No modules no devices everything is original apart from the eproms
N75 is the one for RS2 and brand new
also brand new are Lambda and MAF (original parts)

[Rusty]

Good luck dorting it all out. Getting everything back to standard is always a good way of solving problems because if it doesn't run properly as standard you can eliminate the cam timing from your list of possible explainations.

[veneto rs2]

Anyone ever changed the "rubber" that is situated on the wastegate?
is anywhere in the forum a step by step procedure? (i try searching it but no luck!)

Ciao Stefano

[S2central.net]

You mean the diaphragm - White coloured plastic layer inside the WG that attaches to the actuator valve ?

Its easy enough to remove as follows -

- 8mm socket to remove WG cap nuts - Take GREAT care not to damage threads and/or lose nuts as the WG spring keeps the cap in tension... You need to lean on the cap whilst undoing these nuts

- Now you can see the diaphragm attached to the valve and a circular cap

- Two methods exist for loosening this internal nut... One is to use an impact hammer to prevent the entire assembly rotating... Another is to CAREFULLY use a screwdriver (or similar) to wedge the cap such that you can undo the nut without the assembly moving. The top nut is tight so be careful... If you cannot remove it this way, then the only alternative is to remove the entire WG unit - you will see that the actuator valve has a hex shaped hole to keep it in place while undoing the top nut

- Man it takes longer to explain in typing than to do this job

- The part number for a new diaphragm (they can and do tear occasionally) is 035 145 797 B - not expensive.

When you have the diaphragm removed - easier with entire WG out - you can establish if there is any excessive wear on this valve. It needs to keep a good seal until exhaust pressure is sufficiently high to force to rise and flow gasses out the wastegate. Stiffer springs and good Motronic software help in that department of course to provide good boost regulation, but if the WG valve is mechanically deficient (or the diaphragm is split) then you will struggle to hit target boost.

HTH !

Paul

[twoqu]

This might be helpful too!

http://www.sjmautotechnik.com/parts_products/wginst.html

[A80Avant]

found out that the dyno im going on the 3d of february is a MAHA as well....hope i get some good results!!

[veneto rs2]

Paul Thanks a lot with your explanation and TWOQU link (thanks as well!) i do have a clear procedure to do the job
I order already the new diaphragm from Audi (40 euros) good or not good the thing is been sitting there for twelve years so it's about time to open the thing and have a look inside.
Tecnical question Paul:
If that diaphragm is out of order in some how should'nt make a overboost problem rather then not reaching the exact boost pressure?
I've been reading around the forum and this kind of doubt came on my mind...

Thanks again Stefano

PapVas.................goodluck!!

[A80Avant]

yes well im going to need it...
actually i wanted to ask you,what did they tell you about the specs of the dyno?like the measurements according to losses from the dyno's wheels etc?how much close to road conditions are the figures you are seeing?

[veneto rs2]

No idea PapVas i'm sorry........
The same Dyno ad this out of a RS4 of our club........the guy had 12bhp improvement with Supersprint....
Honestly i tryed the car and it's one of the most "tasty" four wheels i've been in!

in my post in this thread you can see the graphs before and after with Supersprint fitted (was'nt bad before after is even better)

http://audirs.forumfree.net/?t=11381899

Ciao Stefano

[veneto rs2]

Hi everybody!

OK i've done the check with the gauge yesterday.....
results are:
Boost peak stops at 1.8 bar till 4500/5000rpm (i guess that's the overboost limit) in 4th gear with flatten gas pedal pressure drops to 1.2bar and stays there so no leaks

Changed the diaphragm as well (tip of the screwdriver is perfect!) as far as my conceirn the WG is ok the only thing weird that i found was the most of the little nuts where no tighten but the cup was "glued" anyway with the lower chamber.

Right now i have two lets say options or philosopy of motor:

A quick climber with 302hp 449Nm at 3800 rpm

Or on the other hand the possibility to go back on the RS2 cams set up and have a go with it

The thing is i believe that when i bought my RS2 the cam belt had been changed by the previous owner but the guy that did the job did not notice that cam wheel was due to be fitted "out of mark" easy mistake i must say but that must be the reason of the enormous turbolag that i felt and drove me into a different cams timing
I assume that the correct timing is going to be something in between the two setsup that i tryed so far.
So in about 20000km when i will change my belt i will go back on stock setup and do another dyno........... wil keep you posted

Thanks everybody!
Ciao Stefano