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This summer I installed my new Trackspeed engine. Great opportunity to go over everything in the engine bay, refreshing and replacing clamps and hoses and motor mounts during the install. Had an ECU problem which kept me from doing much more than breaking the engine in.
Got the ECU sorted at about 700 miles and at 1,000 swapped out the dinosaur oil to Amsoil 10/40. Started turning up the boost. The previous stock engine had been at 12 psi. So I felt that 15 psi. with a conservative tune would be a good first step. Programmed boost limit and boost targets accordingly and was glad to see 15 psi come up in 1st and 2nd gear. Third gear, the boost dropped off to about 12 psi. I rechecked my map to make sure there wasn't some boost by gear thing enabled ( my previous ECU had corrupted the map ). When I found no issues. I started looking for boost leak, not expecting to find anything after having properly tightened everything during the install.
I didn't get far before finding problems. Every clamp was loose. These are the clamps that come with the FM2 kit, not Ace Hardware hose clamps. 5 out of 6 clamps needed to be tightened after only about 1200 miles. Anyone else experience this kind of thing?
Moral of of the story for me. Always check the simple stuff first. Oh yeah.....always position the bolts on the clamps so that you can get a socket on them.
I just went through the same thing. 10 of 13 clamps leaked. I have a remaining leak somewhere in the intake manifold area and will be posting in my build thread about it. Not sure how to diagnose. I also have a stethoscope coming.
There are these: Somewhat Expensive ones available that purport to solve the problem. Good quality worm clamps (Home Depot all SST, or the ACE ones you mention) have been used by some with good results as well.
Those turbosmart clamps have their own problems as well. You have to crank the bajesus out of them due to some interference with the worm bolt head and the slotted clamp piece. I had to take a grinder to the slotted clamp in order to keep it from interfering.
And yes, you WILL have to re-address boost leaks all the time. Heat, vibration and defects all contribute to it. It is damn annoying and probably one of many reasons why OEMs avoid any kind of higher boost. I run nearly 30psi and am always developing new leaks. Use a stethoscope WITHOUT the bell end and just snoop around with the open tube. You have to pressurize the system and should probably do it with everything nice and hot. Don't be surprised to find a leak in someplace weird. Gaskets fail, over torqued bolts on the manifolds, brake master can leak. I had a sneaky problem with a pinhole at a bung I welded in for a IAT sensor.
I have a remaining leak somewhere in the intake manifold area and will be posting in my build thread about it. Not sure how to diagnose. I also have a stethoscope coming.
Stick a small rubber tube in your ear. You WILL KNOW when the end is in airflow.
I forget what brand I run, it's in my build thread. But they do not come loose, don't require a retighten, and don't leak at 40psi. Pricing was I think 3-5 per clamp.
I usually recommend going back and checking bolts and nuts and such every few hundred miles after turboing or making major changes to the car, or every oil change after that. BP's like to vibrate. I have seen weird **** loosen when it shouldn't.
I have not touched the t-bolt clamps on my car in years. I recently bought a boost leak tested so I'm interested to see if I find a lot of them to be leaking.
I didn't expect so many comments to this post. Apparently boost Leaks are part of the turbo landscape.
For those of you who test for boost leaks by listening for escaping air with a stethoscope or hose, how do you pressurize the system? It seems that you would have block off the turbo side and the throttle body side and get compressed air into the system....somehow?
I'm trying to imagine the process. What have y'all done to test for leaks?
I have a cap for blocking pvc pipe. Bought it at Lowes. Then drilled a 9/16 hole I think and tapped the fitting for 3/8 NPT, then put an air hose fitting in it. That way I can hook my air compressor to it and use that to pressure up and test for leaks. The PVC fitting, I put it in a coupler and clamp it to the pipes.
The 2.25 connects directly to my turbo compressor inlet, after removing the intake elbow. The entire intake system is pressurized, including the IM and and even any cylinders with intake valves open. I would think this would work as long as there is no Intake / Exhaust valve overlap.
At first, I had leaks at 5psi. After tightening the coupling bands, I now have a leak, somewhere in the intake manifold area, at 18 psi. AND, the IAC valve leaks at the electrical connection, but we are not talking about any volume of air that would be meaningful.
I use PVC fittings tapped and installed with a quick connect for my air compressor. I added a small ball valve before the quick connect as well. Then I use silicone couplers to attached to the inlet of the compressor. You don't have to do anything to the throttole body side, the engine does a fine job acting as a cap.
Too many good responses for me to thank everyone individually. My takeaway from this is I can test for boost leaks by capping the tube from the turbo to the input side of the intercooler and leave the output connected to the throttle body. inject some pressure via tire stem valve and air compressor and use Windex, soapy water or a listening aid to search for leaks. Sounds easy enough. Someone questioned what my Intercooler piping was. The tubing itself is silicone and all metal connections seem to be thin wall stainless steel. Flyin Miata supplied stuff. I have seen the same issue with clamps and boost leaks on a friends Miata who also had all FM stuff. Perhaps high quality SS worm drive might be better than the "T" bolt sort of connector?
So, if counting on the engine to not "leak" I'd be expecting the valves to hold the test pressure unless there was a cylinder with intake and exhaust valves all partially open? Can that even happen?
Anyway, I'm going to assemble the PVC fittings and tire valve for a test kit. be nice to be able to chase down any leak issues.
I've acquired the PVC fittings needed and a tire valve stem. I'm going to put together a leak detector kit and go through the whole system next week when I pull my under tray and replace it with the aluminum one, I'll have better access to the clamps n the intercooler.
Right now it's holding 15 psi thru 1st and 2nd but 3rd gear drops off to about 12 psi. after a couple of seconds.
After putting together my PVC test plug and pressurizing, I found the boost leak. It was leaking pretty significantly at the Throttle Body / Intake Manifold connection. It was hard to see since the Skunk II throttle body fastens to the manifold with recessed cap bolts. After tightening down ( with some Loctite ) the car boosted to 16+ where the overboots protection cut ignition. I had to reconfigure my EBC settings to get to the desired 15 psi.
Thanks for all the suggestions on pressure testing techniques.
09-19-2019, 12:00 PM
Boost Leaks
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