I think I found the leak. On either side of the oil inlet on K24 turbos there are these plugs. Looks like the plug on the inside is leaking. Here is a pic of the centre casing of. K24 and you can see the two plus on either side of the oil hole.

 

I have no idea what those are for but I know the K16s don't have them.

 

I am not looking at a picture, I'm going off your description in the first post of where you connected the plug with gauge and the adapter with the air fitting. I haven't connected it like that when I leak test.

 

This is the method I use. The only difference is the plugged cap on mine had a gauge so I can see the exact pressure in the system.

https://www.6speedonline.com/forums/...ig-w-pics.html

 

I understand what you are doing. If you suspect the leaks are from the turbos, why don't you try it like I do and take the hoses off the output side of turbos and put in your pressure tester and plug/gauge directly in them bypassing turbos. At least you can start looking for all the other leaks you probably have. I have spent many hours testing and working on mine..lol

 

That's a good idea. I was just going to fix the leaky plug on the turbo and do the test again which would give me the same results I guess.

 

Scratch that. The air is not coming out of that plug. It's coming out of this hole on the back of the Compressor housing plate where the plaque was riveted to it. WTF? The one on the other turbo looks the same but not sure if it is also leaking. Will check that out.

 

Called the builder of the turbos and those holes should not go all the way through so they had me plug them.


With them plugged the system seems to hold boost now with the boost tester but when I drive it the car still makes only 0.8 bar of boost VS the 1.3 the tune is commanding and the boost comes on very sluggish. Fun times.

 

I know what it probably is...
do you have a IPD or similar plenum?

 

Hi Markski, no I have the stock plenum.

I pinched the lines at the waste gate actuators and the car boosted the same. I starting to look at the N75 solenoid to see if that might be the problem.

 

UPDATE:
So it's still only boosting .9 bar or so on a tune that is commanding 1.3 bar.

Facts: car was running perfect on a 1bar tune in the stock k16s.

Bought a pair of newly built k24/20G billets. Installed them with some 72lbs injectors. Test drove and car only made .9bar rather than 1.3.

Did a boost test and discovered large boost leak on back of both turbo compressor backing plates.

Fixed them and system now holds boost.

Test drive car and it still only makes .9 bar.

Pinched hoses going to wastegate actuators and test drove the car. Car still produced .9 bar. Unpinched the hoses.

Removed hose from the N75 solenoid. The car should now over boost so I was careful when test driving. But guess what. Car still only made .9bar.

Removed N75 solenoid and tested it by putting power to it. It tested fine.

So that is where I am right now.

I have strong feeling the issue is the wastegate actuators themselves but would love to hear what you guys think.

Thanks!!

 

any chance you still have factory w/g and not 1 bar w/g installed?

 

They might be, but a good set of stock actuators should be ok. If the spring has weakend over the years then the flow/pressure will blow open the wastegate and I will not be able to see peak boost. This is what I think is happening.

 

You could, carefully, block the hoses to the W/G actuators and see if it makes more boost. Just be VERY careful not to overboost it. Say a light pull in second or third?

 

Done. Made no difference. Even used wire to stop the wastegate actuators from opening and still only made .9 bar. I made another thread with just the facts so hopefully I get this sorted out.