xupkid2

Ive got a 26/8 Turbo that was rebuilt a year and a half ago. I am running the Turbo Cup chips so I should be at 1BAR boost (14.5 PSI). The issue I am having is that during a boost test this weekend I was getting about 12 pds of boost. My vaccum hoses seem fine as well as my intercooler hoses. Wondering where else to start looking for this leak. BTW, I also have a Lindsey Clubgate, Lindsey crossover, SFR SS Headers, copper gaskets.

Thanks
Brian

Black51

So the lines 'seem' fine, but are they fine? Try pressurizing the system to see if there are any leaks when the system is under pressure. Sometimes leaks don't reveal themselves until the car is under boost.

xupkid2

Ill try pressurizing the system this weekend. I have the Lindsey lines with zipties on all connections so the lines seem less likely than something else like the x-over. Any thoughts on the best way to pressurize the system?

Also anyone have ideas on how to fog test the system via homemade setup? I dont want to take it to a shop unless I have to right now.

Thanks
Brian

User 52121

Do you have a MityVac vacuum tester? If not you can borrow mine.

I can swing over this weekend or some night this week after work if you want a hand. Or worst case bring the car over here in the trailer and we can run it down the backroads to test.

Though 12psi vs. 14 tells me it's probably not a vac leak on the control side. Either the WG is soft, or you have another kind of leak somewhere. Boost hoses or exhaust.

If you disconnect the line going to the WG, then you SHOULD get LOTS of boost. Quick road test will tell you that. Just be prepared to shut it down asap so you don't hurt anything.

Where are you reading the 12psi? On the PCA tech inspector's gauge or your own? Are you sure the gauge is good?

This should be a pretty easy thing to figure out. Give me a call tomorrow.

Oh and I've seen zip ties cause problems on vac lines. They don't close to a full circle - the latch mechanism comes in at a 90-degree angle. You could wind up creating a pinch/ripple (hard to describe.) If you feel you must secure the lines, use proper clamps or safety wire instead.

Black51

Van put up a nice pressure vid on youtube:

"DIY - how to pressurize your 944 turbo intake system"

Put that in the search bar and smoke it.

xupkid2

Thats a helpful video, will it also show leaks in the headers, x-over, wastegate, etc???

xupkid2

Jim, Ill call you today

User 52121

I haven't watched that video that was posted here but if you can't make that work, I have somewhere in my garage a collection of pieces that I used to pressure test my intake system for leaks back when I was trying to install that crap last summer. Was able to pressure test the system from the J-boot to the throttle plate. I'll have to scratch my head a bit to remember WTF I did but it did work well enough.

Also I'm sure Mark has a smoke machine thing if you really want to use one of those.

User 52121

Oh and did you have the turbo rebuilt after your "off" in T12 at RA? Might want to double check your compressor side fins on the turbo and make sure they're in good shape and that nothing got sucked in through there.

I've also got a leakdown tester if it comes to that.

Black51

You'll hear it if there is a leak anywhere. You might have to walk around/under the safely hoisted car to hear if it's really small. But if it were really small, you'd probably not be having such a major issue.

I'm not sure on this one, but if you have an aftermarket boost gauge, you could also look at it while the system is under pressure to see if it's gauging pressure correctly. The ignition may have to be on... doubt it, but not sure.

Oddjob

Was the test done by a scrutineer checking boost at a Club Race (Mid-OH)? Do you have another gage to check/test the accuracy of that reading? 3rd or 4th gear run, not 2nd right?

Was the 12 psi held to redline or did it drop off?

Do you know that the car did make 14-15 psig boost previously? Did the car feel down on power (running 12 psi) compared to before?

Are the cup chips the 28 pin DME set, copies of the Canadian Rothmans chips?

schip43

Any noise when it happens?

xupkid2

Hey Jim

The test was done by a scruit using the Porsche factory boost tester. The reading he got on his gauge matched the reading I had on my aftermarket boost gauge in the car so it seemed accurate. The chips Im running are the 28 pin cup chips so it seems like Im missing about 2-2.5pds of boost. The max boost I can get at any point in the throttle is about 12-12.5 pds. Ive never had 14-15pds since I put the car together but I never put too much thought into it. Just assumed I never looked at the gauge at the right time. Im assuming there is some type of leak that is causing this loss in boost. Wouldn't surprise me if it was exhaust system related since Ive never trusted the mating on the cross over. Wish I could use bolts vs the v-band.

User 52121

You're running both sets of Cup chips, right? DME *and* KLR cup chips?

xupkid2

yes, both sets. The KLR is a 24 pin, DME is 28