RS2- Just had a dyno run...power down (any thoughts?)

[weta.worker]

hiya, I've been told by my new mechanic (i've ditched Audi due to the paaain!) that the RS2 is down on power so we got it dyno'd

here are the results (and some pics - video is still uploading to youtube , but not much to be seen there)

the guys running the dyno said out of 4 runs the car ran 2 different ways (this way below twice and 2 other runs at slightly lower power)

runs 2 and 4 are below. 1 and 3 were slightly lower.

- Power , 170kw at the wheels (around 18 > 20% drive train loss) = 204ish KW @ 20% loss

Jons (another RS2 owner in NZ) plot shows 270bp \ 201kw = 240kw+. @ %20 loss





My plot (blue isn't the best colour on black with this!)





So my power is down, my boost is down

Jons plot (he thinks it's OEM - it was before his ownership)



I'm not sure if 30kw can be found in 3 psi of boost?

Have flicked info to my mechanic

Prior to this run I'd had Audi (I'm reading off the many invoices in front of me...)

- replaced N75
- replaced wastegate actuator
- replaced vacuum lines
- replaced engine speed sensor
- replaced O2 sensor
- injectors out and serviced

and the new mechanics have

- replaced MAF with another 2nd hand unit

Hoping the greater 'Internet oracle' has some ideas?

Cheers!

John

[prj]

Yeah, instead of changing random parts, have you done a boost leak test?

[weta.worker]

Yeah, instead of changing random parts, have you done a boost leak test?

yup.

all within tolerance.

when I say yup, I mean that the mechanic has.

and the parts that have been replaced were due to them being faulty (well so I was told)

[prj]

yup.

all within tolerance.

when I say yup, I mean that the mechanic has.

Please explain how a boost leak test can be "within tolerance" ???
How exactly was it performed?

[weta.worker]

Please explain how a boost leak test can be "within tolerance" ???
How exactly was it performed?

I believe they used a smoke and pressure test. and apparently there is a tolerance and it was within this

this is all info from the mechanics I'm using

I moved away from Audi as I thought they weren't competent and to a mechanical outfit that specialise in a range of Euros of different ages and who have great feedback.

I can't remember the exact numbers they told me (with regards to the tolerance). I asked them to perform a boost leak test and they said they've done many before and they were happy with the results.

In your opinion, does this look like a boost leak?

[prj]

I believe they used a smoke and pressure test. and apparently there is a tolerance and it was within this

this is all info from the mechanics I'm using

I moved away from Audi as I thought they weren't competent and to a mechanical outfit that specialise in a range of Euros of different ages and who have great feedback.

I can't remember the exact numbers they told me (with regards to the tolerance). I asked them to perform a boost leak test and they said they've done many before and they were happy with the results.

And I still think it was not done correctly, as the smoke machines pressurize intakes usually at very low pressure, which are not suited for anything other than naturally aspirated engines.

Loss of 3 psi is exactly what is responsible for your lack of power, as on a stock car the turbo has a lot of room, and it also means your mixture is pig rich and timing is late if you have a leak.

I don't know how to sugar coat this, so I won't - if you are unable to do any work on your car nor want to, then owning a 20 year old car is probably not a very good idea.
This forum and some hands that grow from the right place is all that is needed to fix things and get things running correctly.

[weta.worker]

And I still think it was not done correctly, as the smoke machines pressurize intakes usually at very low pressure, which are not suited for anything other than naturally aspirated engines.

Loss of 3 psi is exactly what is responsible for your lack of power, as on a stock car the turbo has a lot of room, and it also means your mixture is pig rich and timing is late if you have a leak.

I don't know how to sugar coat this, so I won't - if you are unable to do any work on your car nor want to, then owning a 20 year old car is probably not a very good idea.
This forum and some hands that grow from the right place is all that is needed to fix things and get things running correctly.

Hahahaha - well thanks (i guess!)

No sugar coating there!

[prj]

All you need is a simple plug for the MAF-> Turbo hose, disconnect the breather, put 1 bar in and make sure it does not drop to zero for 30 seconds.

Most people either do not pressure test enough, think that it is supposed to drop very fast, or disconnect the intake manifold, which makes the whole thing an excercise in futility.

If your mechanic has not done a boost leak test on an RS2 before, most likely it was not done right.
If you are seeing too little boost with a stock map, most likely you have a leak.
It should hold 1.4 bar.

[prj]

P.S.

Stock boost map, absolute pressure, kpa:

[weta.worker]

P.S.

Stock boost map, absolute pressure, kpa:

thanks!

and thanks for the advice (with or without sugar)

I love this car but I've got no time to dedicate to it (well not until my 3 children grow up a bit and provided we stop having more!)

thanks again - great advice that I'll pass onto the guys I'm using (trying not to offend them too much)

[prj]

My idea is not to offend, but I am just saying how it is.
If you have three kids you should probably be driving something new and hasslefree that only needs oil changes

It's a proper pain to own any older car, as things go wrong all the time, there are not enough parts available, and most people have no idea what they are looking at and how things work.

Sad, but true.
Hope your guys can sort it. UrS4Boy had a very good writeup on how a boost leak test should be performed. Try to find the thread, print it, and give it to them.

[weta.worker]

all good. thanks again.

the rs2 is my car , the rs4 is our 'reliable' car....

will ask the mechanics to do the test again but using your method "All you need is a simple plug for the MAF-> Turbo hose, disconnect the breather, put 1 bar in and make sure it does not drop to zero for 30 seconds."

and also get them to take a look at this (i'm pretty sure they've taken a look, but if its leaking I'll get them to go over it with a fine tooth comb)

http://www.s2forum.com/forum/showthread.php?t=63974&highlight=boost+pressure+leak+testing

[prj]

RS4 reliable

Mine spends more time in bits than on the road.

[weta.worker]

now with a very non eventful video

http://www.youtube.com/watch?v=01LRhhb25bk

[Mcstiff]

If no leaks are found I'd check for any damage to the catalytic honeycomb. Exhaust restrictions can cause similar symptoms.