newbie turbo question

[Lucutus]

had some work done on my new mk3 7m-gte . 91.

And my car dude took my turbo off, but left out the gasket that goes between the turbo and the turbine outlet elbow. he said that they should really be "dry docked - without gasket" is he talking turd ? will this gasket not being present effect my performance?

Also he removed my dump valve and put it in the place he thought it should go , he said it was correct but the car didnt go right so we put it back. with out a photo i cant really explain it , i will go take a pic. so u guys cant tell if its in the right place. :)
http://www.backpackersplanet.com/spare/dumpvalve
He also applied a bleed valve - think im boosting around 10 psi - after reading your posts i have hear that this will kill my HG real quick, if you were me would u set it back down to 8 psi? i just spent 1000 on the car after a week of owning it.. not in the mood to lose the HG... :rant:

any ideas what mph i should pull in 3rd gear at say 6x rmp ?

Thank you for all your help .

Luke.

[JonArgraig]

Dump valve looks fine in the pic but the bleed valve is a little crude for a supe for getting the boost up,

10psi ? ? ? , On a stock gasket I'll just run the stock boost

[Lucutus]

Dump valve looks fine in the pic but the bleed valve is a little crude for a supe for getting the boost up,

10psi ? ? ? , On a stock gasket I'll just run the stock boost


Thanks , ok i will take off the BV , wondered about the DV cuz it dont make a great deal of noise - there is an ajustable bolt on top of the DV what does it do ?

L .

[gtstarga]

Err is it me or is the dv in the wrongplace??? should be where the bolt is blanking off the 3000 pipe. Currently it on the intake.... thats not right!!! :banghead:

[Sean.W]

Err is it me or is the dv in the wrongplace??? should be where the bolt is blanking off the 3000 pipe. Currently it on the intake.... thats not right!!! :banghead:


Yep , that looks the wrong way round , at least i hope so because mines set up the other way :confused:

[Sean]

Even I know that, that is wrong :rant:

[Lofty]

Yes, the DV valve is on the wrong way around. You will be getting compressor stall between shifts. The good news with your current setup is that any excess pressure in the inlet pipe will be vented and the DV will never wear out. :banghead:

Yes, there is supposed to be a gasket at the turbo elbow but it will only effect performance if there is a leak.

Don't take your car there ever again.

"Use the Force, Luke" - Obi-wan

"DV valve correctly fit, must you" - Yoda

[Lucutus]

Yes, the DV valve is on the wrong way around. You will be getting compressor stall between shifts. The good news with your current setup is that any excess pressure in the inlet pipe will be vented and the DV will never wear out. :banghead:

Yes, there is supposed to be a gasket at the turbo elbow but it will only effect performance if there is a leak.

Don't take your car there ever again.

"Use the Force, Luke" - Obi-wan

"DV valve correctly fit, must you" - Yoda


Yes My car dude put the DV where you guys are saying and i know ur right but when he did - the car went like a sack of cack? he tested the dump valve and it didnt leak so -- WTF???

Getting a better turbo off a member ANh. Will put the dump valve back where it should be - but if it make the car go like pooh again what do i do ? as there is nothing wrong with the dumper....

AArgggggh :banghead:

The Force aint with me, help me obi-one your my only hope. :notworthy

[Lofty]

Get the turbo->turbo elbow gasket and fit it. A leak here will cause performance problems.

The DV won't leak because the inlet pipe only sees vacuum and this won't be strong enough to open the bypass, luckly, otherwise you would be running lean. Lean + 10psi = bad! The DV is supposed to be on the 3000 pipe where the boost is.

Don't take your car back there ... ever.

"I got a bad feeling about this..." various people in every episode.

[Lucutus]

Get the turbo->turbo elbow gasket and fit it. A leak here will cause performance problems.

The DV won't leak because the inlet pipe only sees vacuum and this won't be strong enough to open the bypass, luckly, otherwise you would be running lean. Lean + 10psi = bad! The DV is supposed to be on the 3000 pipe where the boost is.

Don't take your car back there ... ever.

"I got a bad feeling about this..." various people in every episode.
ANy one fancy sending a pic of how there dump valve is set up , or know of an online diagrame? cant tell from the factory diagrame cuz the stock DV has more holes for more pipes.

Thanks guys.

"Thats no moon!"


L,

[Lucutus]

ANy one fancy sending a pic of how there dump valve is set up , or know of an online diagrame? cant tell from the factory diagrame cuz the stock DV has more holes for more pipes.

Thanks guys.

"Thats no moon!"


L,


OK now im deeply worried, for the very few DV installs i managed to find it looks like its meant to have three pipes coming off the DV ? my DV only has 2 pipes ..... mmmmm... bugger

or am i talking out of my newbie butt.

[Lofty]

The OEM setup is a Bypass valve (BV) not a Dump valve (DV) that recirculates back into the inlet pipe and has 3 pipes (In, Out and Boost/Vacuum). A DV vents to Atmosphere and has only 2 pipes (In and Boost/Vacuum)

I haven't go a pic but basically the DV fits on the 3000 pipe and the inlet pipe needs to be blocked. Your mechanic has installed in **** about face.

Did I mention that you should never take your car there again, ever?

"Is that a lightsabre in your pocket or are you just pleased to see me?"

[Lucutus]

Ok,

Its finaly sorted after a crap load of money.

Anh's turbo is in top condition, dump vavle is in the right place and working correctly.

But guess what it still aint as "pully" as it was before the cam belt fell off.

I dont understand it.

Nothing has changed i have a better turbo on the car and its boosted to 9 psi. yet it still doesnt have the magic that it had for the first week i had the car.

Any ideas?

The old turbo - made a screaming whistle noise - the new turbo doesnt.
are they meant too ?

its doing my head in ...

New cam belt , new rocker cover seals, bleed vavle, dump valve working, very good contion 2nd hand turbo, KnN replacement filter - boosting 9 psi.
No overheating, engine sounds like a kitten, no smoke, no leaks, everything in tip top shape....

all that has changed as far as i know - I the turbo to elbow gasket is not present - and the DV is in the correct place.

Yet its slower..... :rant: :rant: :rant:

I need the force back !!!

[Lofty]

But guess what it still aint as "pully" as it was before the cam belt fell off.
It is possible that the power delivery is now smoother. Are you sure that the car is slower?

The old turbo - made a screaming whistle noise - the new turbo doesnt.
are they meant too ?
I've found that the turbo is quite quiet at standardish boost. At 10psi+ mine does start to make more noise though.

You could also check that the cambelt hasn't been installed 1 tooth out.

It doesn't sound like your turbo elbow is leaking but you may want to replace the missing gasket anyway.

[buttmunch]

Surly looking at the pic of the dump valve fitted incorrectly, off boost he was pulling in unmetered air as the valve is open untill vacume turns to boost?? On the subject of it not pulling like it used to like Lofty said your timing might be out if its a tooth retarded it will not pull from low revs if its a tooth advance you would be getting hellish deonation which would also lead to sluggishness but you would have done some serious damage to the engine by now if that were true.

[Lofty]

Surly looking at the pic of the dump valve fitted incorrectly, off boost he was pulling in unmetered air as the valve is open untill vacume turns to boost??
I had assumed from his last post that he now has the DV fitted correctly.

I think that it is likely that when it was fitted in the wrong place it wasn't doing anything. Normally these valves rely on boost to be one side of a piston/diaphram and vacuum the other to open the valve as there is also a spring to help keep the valve closed otherwise. If it did manage to open though you would be correct.

I think there are 3 likely scenarios in an engine:
1. Equal pressure/vacuum both sides of the valve means that the spring keeps the valve shut.
2. Boost one side and vacuum the other means that the piston will be forced open when the boost pressure overcomes the spring, which would be at a low boost.
3. Some brief transitional moments as the pressures change from one thing to another meaning that the valve may oscillate between open and closed.

"and don't call me Shirley"

[formal]

Ignition timing would cause detonation if it was advanced not cam timing.

[Lucutus]

You might be right lofty, about it being just as quick but smoother, - the only real test is too put it up against my mates VW VR6 again . before the cam, i was on his bumper with power to spare.

after the cam - well, ... it was a tad embracing.

as for the cam belt postion, i have had it checked and it is accurate.

Guess i will just have to come to one of your meets one day and let one of you thrape the crap out of her, see what u think...

if she lasts that long :gay:

Thanks again for the assist..

[darket69]

hey dude .. would you like me to come over and sort it out for you? ..the only thing i will charge you is fuel and tea .. i do alot of members cars and have ****e loads of spares.. let me know

ED

07789857569

[buttmunch]

Ignition timing would cause detonation if it was advanced not cam timing.

Now call me daft but the cam position sensor operates off the cam and if sed cam is 1 tooth out then the ignition timing must be out to??

[Lofty]

I guess that this would all be relative to which cam were out, in which direction and whether someone had tried to set the ignition timing since the new belt was installed, after all ignition timing is based upon crank position. Although it uses the exhaust cam to get a reference it would expect this to be in the right place. That does raise the question of how adjustable cam gears will effect ignition timing though. Anybody know? For example if you retard the exhaust cam using cam gears are you also advancing the ignition timing without realising it?

Edit: Having thought about it I think that you probably would advance the timing but this could be adjusted back in the normal way.

[Trevor]

Now call me daft but the cam position sensor operates off the cam and if sed cam is 1 tooth out then the ignition timing must be out to??
The ignition timing is set according to the crankshaft position, so providing the ignition timing is set AFTER changing/messing about with the camshaft drive belt it will be correct irrespective of the exhaust camshaft position.

Of course, if the ignition timing was not set after the camshaft drive belt change and the exhaust cam was out relative to the crankshaft, then the ignition timing would also be out.