Found 14 vacuum leaks, and Exhaust leaks
 

If your like me, you always think of an inventive way of making your car run better.

I thought my car was slightly down on power, so I desided to do a poor man's pressure/leakdown test of the intake system. I used an air compressor with an inline filter, a can of soup which fits nicly into my costom TID, and some rattle can caps to plug up the exhaust tips.

I set the compressor output at first to 15 PSI and started presurizing the system through a spare vacuum line. At first my boost guage would not get much over 5psi, but after solving the below leaks I was able to pressure the system to 13psi with the compressor set at 15psi. Exdhaust leaks are probably hindering a better reading...

Here's a detailed list of all the leaks I foundl

14 total leaks

1. Throttle bott pivot point -an oring had vanished and was letting air pass out the back of the TB at the butterfly's pivot point. -ORing from Home Depot
2. My Greddy FMIC was leaking at the three inch coupler nearest the TB - Got some nice tbolt clamps from Autozone.
3. My Greddy TB adaptor (just after the IC piping) was leaking at the TB - Gasket was flattened - RTV
4. My cold start assist solenoid had a major leak from what looked like a design flaw, but it may have been because my UIM was simplified -Made a custom paper gasket for it
5. My Aeromotive FPR leaked from the 1/4 NPT fitting - Solved weith teflon tape
6. My Aeromotive FPR leaked from the top adjustment nut/bolt -again solved with teflon tape and reset fuel pressure.
7. When my HKS SS BOV vacuum line is NOT connected the BOV leaks from the main valve. - Leave BOV connected to avoid this as the valve pushes closed when boosting. I still think the BOV mayy leak though.
8. My turbo leaks past the oil seals probably by design, so I ended up re-testing pressure of the system AFTER the turbo.
9. I had 6 count SIX poor man vacuum caps made from left over vac line and plugged with appropriate sized screw - EACH ONE LEAKED at 10PSI!! Even zip tied ones leaked!! - Replaced with 30 cent vac caps

So now my engine actually sounds healthy!
Noticable gains:
1. My turbo can now make boost at about 2000 rpm much easier. It was kinda painstaking before.
2. My boost pressure does not drop off at high rpm like it used to
3. I have my Haltech 3bar tee-d off the same line as my FPR, so that was probably throwing off the reading im sure.
4. My FPR is now doing a better job and needed a lot of adjustment to get fuel right.
5. About .5 af too rich at 15psi and +6000 rpm on account of the haltech probably hitting an untuned map.


Just to add, I found several leaky components to the exhaust system. I'll have to get those leaks fixed next time but I dont think they are as important as intake leaks.

fits nicly into my costom TID?

A can of soup was the quickest thing I could find that fit perfectly clamped inside my turbo inlet duct. It works cause the can has a nice lip.

Very clever test!

im thinking of presurising the intake on s5 na, with tire electric pump, since the boost will leak through combustion the pump will be on all the time. Then take soapy water and pray it around all areas. The slimy stuff they use for tire installation would work better i think but dont know where to get it.
You think this is good test for N/A?

Im sure it would work somewhat. Just dont let your pressure get too high; on NAs you probably dont have as many check valves and wierd things like your charcoal canister and boost sensor really should not be seeing high boost. I'd say leave it at a few psi to start. It would be much easier with a large compressor as those electric tire ones dont flow very much at all.

I also had to reset my manual boost controller; seems it was actually seeing a lower pressure before doing all this, and although before it was holding the car at 13-15 psi, now its holding a rock steady 13 psi. Power gain to 15psi!!

Finnaly my motor is not so lazy at low rpms! :) Before doing all this, 1st gear wouldnt boost much past 10psi; I thought it was just cause of turbo spool lag and the engine getting to red line too quickly, but in actuallity it was all these dang intake leaks!! Boost now comes on a lot stronger in 1st gear! I've gotta take her to the 1/4 to see if I can get a better than 2.6 60 foot time!

I like testing leaks with a cig, light it and move it around intake gaskets and etc and have someone on the gas too a little and you will see the smoke get pulled in

i'm glad to hear that thing finally got some TLC :)

now go to the dyno and see if you can make any more power than i did when i owned that car a couple years ago :)