Author Topic: 1.6l NA-TD boost problem (Read 5284 times)

vanagonturbo · « **on:** May 09, 2006, 07:51:57 pm »

Ok, well I have been lurking here for a while. Glad to see Jake is in here. Good guy, known him since he was just a kid with his diesel rabbit

Anyway, here is something that I hope might be easy. I dont really want to take the turbo off right now.

1980 Scirocco. 1.6 NA (recent freshen up). TD pump. TD manifolds (intake and exhaust). Pump timing set to 1.05mm. TDI intercooler. 2" piping. Recirculation valve screw is all the way in.

Wastegate plugged. I can only get 10 psi out of the thing. Turbo sounds normal, ran it with the intake plumbing off and there is lots of air coming out after a few revs.

any ideas? I would prefer it to have the standard 18psi after this mod but it just wont do it. No boost leaks either.

Thanks.

Chris DeLong

hillfolk'r · « **Reply #1 on:** May 09, 2006, 08:14:22 pm »

you gettin boost pressure to the lda??lookfor a leakin the hose...,no boost to it,no fuel,no power,its a vicious circle

vanagonturbo · « **Reply #2 on:** May 09, 2006, 10:42:09 pm »

Yup. LDA has brand new line connected to it. Guage is attached in between the line form the intake manifold and the LDA.

checked gauge and its good too. all connections to the gauge are good. I have not done the fuel tweak on the pump yet, but one of my employees did the same things with his 85 jetta and was getting 18psi. So thats what leads me to think something is wrong with the compressor. Hence the reason I dont want to take it out

Also, my employees car was a factory TD and the thing that I built is cobbled together with numerous parts from unknown origin.

vwmike · « **Reply #3 on:** May 10, 2006, 12:08:53 am »

Chris, are you sure the pop-valve in the intake manifold is not opening? When i first added a boost controller to my 1.6td boost did not increase. It took additional fuel for boost to increase further. My boost pressure is largely regulated by fuel flow right now. I was sitting at around 26 psi before but I backed fuel down to reduce smoke a bit.

While you're on here, Aaron said you had a TDI fuel gauge sender/pickup. I would assume that would fit into the mk3 gas tank, correct? I was going to get a full tank from Gundies but they proved to be flakey and I'm not sure I feel like driving to Graham to deal with them.

vanagonturbo · « **Reply #4 on:** May 10, 2006, 08:37:29 am »

Hey Mike, yeah I even swapped the Recirc valve for the one that was on Robs engine (known 18psi engine) and it didnt make a difference.

I know boost is really dependant on fuel, but like I said before, my buddy had his car at 18 psi with no mods to the fuel. FWIW, I can get 30 psi in my Vanagon with out modifying the fuel.

Mike, yeah that sender came out of a 98 Jetta so I am going to guess that it will work

vwmike · « **Reply #5 on:** May 10, 2006, 10:11:05 am »

It seems that no two cars are created equal. I would try giving it a little more fuel and see if boost increases. Are you using an EGT gauge? Whats the setup in your van? That's a lot more mass to haul around and increased load will obviously generate more heat and therefore boost pressure.

vanagonturbo · « **Reply #6 on:** May 10, 2006, 10:33:19 am »

no EGT yet. I will try the fueling and see if that helps.

The Vanagon is an AAZ, no intercooler. Boost is set at about 25 psi and EGTs are around 1k during cruise on the freeway at 70 MPH. Still working on the fueling as it has some flat spots throughout the rpm range.

vwmike · « **Reply #7 on:** May 10, 2006, 10:55:12 am »

If the AAZ is using the stock turbo then it should be a K14 which is quite a bit easier to make a lot of boost on as it is considerably smaller.

vanagonturbo · « **Reply #8 on:** May 10, 2006, 08:56:05 pm »

Yeah the Vanagon is on the K14. I know it will build boost really quickly. Sustained boost pressure is another story though.

So I tweaked the fuel a bit more on the IP. Still no change. Man I should really get an EGT on this thing. Clouds of smoke now. Tailgaters beware

10PSI max. I guess its time to take the charger off and see whats going on in there. Frankenrocco needs more power

dennis m king · « **Reply #9 on:** May 13, 2006, 10:11:58 pm »

for mid 80s 1.6 tds in my A2 book 10 psi is stock max boost i wish it was 18 psi.

vanagonturbo · « **Reply #10 on:** May 17, 2006, 07:36:24 pm »

Yeah, I know what the book says. Sometimes the book is wrong. Especially if you start messing with things

Update: I took the turbo off and took it all apart. Everything looks perfect. Couldnt ask for a better turbo.

Next step: remove stock 1.25" exhaust system and install 2.5" system. I think the restriction might be somewhat of a problem. Although, Robs car still had the stock exhaust system for the Jetta. So I dont know. I thought about putting Robs turbo on and see what happens, but it is the exact same part number.

I also removed all the lines that go to the wastegate. Funny thing, when I had the turbo apart, there was a tiny hole nest to the wastgate valve. This hole leads to the wastgate actuator. It is a very small bleed hole. I didnt do anything about it, jsut an obvservance. The wastgate connections have all been completely disconnected and removed. The pressure output from the compressor scroll has been plugged as well.

So basically, does anyone have a theory on why the factory TD engine with the same turbo (wastgate bypassed and plugged, BOV screw all the way in) will put out 18 psi and the factory TD stuff put onto an N/A engine will only put out 10 psi with the same mods?

Thanks for the input!

Chris DeLong

vanagonturbo · « **Reply #11 on:** May 17, 2006, 09:12:50 pm »

I bumped the smoke screw up a bit and all I got was more smoke.

Valve lash has not been checked recently, but I am pretty certain its within spec (I will double check though)

Intercooler piping is good, no leaks.

Turbine housing does not leak.

I really should put an EGT gauge on it. I know that if I increase the boost then the EGTs will drop. I am not really too worried about the longevity due to lack of piston squirters. I know that if I dial in the pressure and and fuel right, there wont be a problem with the lack of squirters.

Could the increased compression from the NA engine cause this problem? I cant see how it would, but maybe there is something I am missing.

Thanks again for the input.

dennis m king · « **Reply #12 on:** May 18, 2006, 06:34:43 pm »

that is a head scratcher. as for compression i thought my book has them the same. the cam most likely is the same but who knows. i would say a leak down test is needed. it just maybe tired.

vanagonturbo · « **Reply #13 on:** May 18, 2006, 11:14:15 pm »

Yes the car has an intercooler. Its from an AHU TDI. 2" piping. ITs great fun after 70mph. The intercooler is doing its job.

Last I checked, compression ratio was 24:1 on the NA unit and 22:1 on the turbo models. This was also many years ago and at that time I didnt question the Bentley manual (suffice it to say, I had to make corrections today on the manual for the A2 regarding CIS pinouts).