26 lbs boost, head gasket...poof

[R.O.R-2.0]

Efficiency range being what psi? I think I will start with 18 and see how it works.

im not EXACTLY sure what the specific numbers, but im gonna say that they are efficient to about 20-22psi or so..

[rodpaslow]

Sounds good enough for a 1.6.  What do you run yours up to?

[R.O.R-2.0]

with proper timing and fueling, i can only get mine to about 22 psi or so.. but my vanes are non-functional. when i had super retarded timing, i could hit 30+psi quite easily. around 26psi, the turbo would start screaming from overspeed.

[rodpaslow]

The head gasket has been replaced and I made a few other changes, I have a boost can now to back off the boost, got rid of stock air box-changed to a larger open air filter, etc.

I started the car up yesterday, ran fine with the  (1.6td) advance/fast idle lever pulled, with this off though it was kind of a lopey idle.  I haven't re-adjusted the timing yet - would timing be the issue?

[RabbitJockey]

yeah sounds like u got it retarded

[rodpaslow]

Tanks

[R.O.R-2.0]

the retarded timing would also cause your ridiculous amount of boost.. if your gonna be running that much boost, out of that small of a turbo, then i would rig up a exhaust manifold pressure gauge.. drive pressure goes sky high on these little VNTs in the upper RPMs/high boost levels..

excessive drive pressure vaporizes head gaskets, and sometimes blocks..

[rodpaslow]

I don't plan on going over about 18 psi with the other vnt 15 now installed.  I have since installed a boost can and a much better setup for vnt control than I originally had.  I've been having trouble, for some reason, to get it to run properly since replacing the head gasket.  Yesterday I re-timed it starting with the timing belt making sure everything was good there and did the dial gauge thing and it's set to 1.00mm right on the money.  Like I said before it starts and runs properly with the high idle/advance lever on, but lopes for a couple minutes before the idle smooths out.  I didn't have that issue before.  The engine has a nice snap to it so I think timing is good now, maybe once I run it for more than a few minutes and get it to warm right up, this will disappear.

Next is just to save up for the vnt 17 hybrid so I can run 26 psi without blowing up the turbo.

[nathan_b]

glow plug?

maybe a burnt valve

[fatmobile]

I hit 35psi on my VNT, a couple times and had no problem.
 I had a good block vent.

i hit OVER 35psi with a 1.5D that had a VNT bolted to it.. then shortly after, the head ALMOST left the block. 7 head bolt bosses were toasted. many cracked soo badly that they would not torque at all..

still drove the car home the next day with the head gasket blown in almost a dozen spots.. only took 5 gallons of water to drive 2 miles, im thinking i had some sort of a SMALL LEAK for it to use that much water.. lol..

retarded timing is the easiest way to over-boost these VNTs..

ever since ive had my engine timed good, its been hard to get the VNT out of its efficiency range..

 I think why my little 1.5 survived 35psi and yours didn't is: mine had head studs. You still had the stock 11mm headbolts right?

[R.O.R-2.0]

I hit 35psi on my VNT, a couple times and had no problem.
 I had a good block vent.

i hit OVER 35psi with a 1.5D that had a VNT bolted to it.. then shortly after, the head ALMOST left the block. 7 head bolt bosses were toasted. many cracked soo badly that they would not torque at all..

still drove the car home the next day with the head gasket blown in almost a dozen spots.. only took 5 gallons of water to drive 2 miles, im thinking i had some sort of a SMALL LEAK for it to use that much water.. lol..

retarded timing is the easiest way to over-boost these VNTs..

ever since ive had my engine timed good, its been hard to get the VNT out of its efficiency range..

 I think why my little 1.5 survived 35psi and yours didn't is: mine had head studs. You still had the stock 11mm headbolts right?

yup, stock non-stretch bolts. shortest amount of threads out of any oem VW bolt. even the 11mm gasser stretch bolts had more bolt threading into the block..

[rodpaslow]

I finally took mine for a run yesterday, but I think I need a boost controller to control my boost can as I can get maybe 5 psi held and if just slowly accelerating it drops off to 0 rather quickly.  I almost thought I had a boost leak but everything is tight.  I can hear something hissing, but i finally changed to an open element air filter and I think that's just the turbo pulling in air.
I might disconnect my boost controller and see if the boost comes up like it used to and maybe test it up to about 15 or 20 psi.  Once I fit a boost controller I can bring it up slowly. 

I certainly notice with the egts, on about 5 lbs of boost it runs up to 1100° quickly.   I might have to back off the fueling at 15-18 psi it will be up to and past 1250° in no time at all...

So far so good with a newly installed old VNT...

[rodpaslow]

My boost can nut that held to the controller came off and the vanes were full open that's why I was getting only 5 psi - I tried last night and it will put out 18-20 psi no problem.

Please can someone answer this - if you have an open cone style air filter-when the turbo is pulling in air like  10-15 psi or so, can you hear it doing this?  I'm still concerned I have a boost leak somewhere, as that is almost what it sounds like.

[R.O.R-2.0]

i hear the exhaust more than the intake. i have a pod style filter.

only time ive had a loud intake, was when my filter was in the rain tray. and it was only at idle.

[Swartzvw]

My boost can nut that held to the controller came off and the vanes were full open that's why I was getting only 5 psi - I tried last night and it will put out 18-20 psi no problem.

Please can someone answer this - if you have an open cone style air filter-when the turbo is pulling in air like  10-15 psi or so, can you hear it doing this?  I'm still concerned I have a boost leak somewhere, as that is almost what it sounds like.

I hear mine doing this as well, sounds like a boost leak but i think its just the turbo moving air.