I hates me some boost/vaccuum leaks...: Grassroots Motorsports forum: Grassroots Motorsports Magazine

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May 30, 2011 9:12 p.m. BoxheadTim SuperDork

The Talon obviously has been a little tweaked under the hood and as a result, one of the vacuum fittings on the inlet manifold isn't connected to anything anymore. There's also nothing that looks like it'll like to be connected to. So far, so good.

Once I figured out that this open connector was the reason the engine idled like E36 M3 (not really a surprise), I capped it off and hey presto, smooth-ish idle.

Only that all the caps I've managed to find so far are all push-fit thin vinyl caps or similar and somewhere between the first and second application of boost, they blow off. I've currently fitted one and try to keep it on with a cable tie but I'm pretty sure that's not going to hold either, and that's not even going anywhere near full boost.

So, I either need something that's more sturdy for the cap that doesn't blow off that easily, or remove the vacuum fitting and plug it with something.

I vaguely remember seeing some brass plugs in a motorsports catalogue in the UK that were made for this sort of purpose but my google-fu has deserted me - has anybody seem them over here and has an idea where to get them?
May 30, 2011 9:16 p.m. turbojunker HalfDork

I've used the rubber caps you buy at auto parts stores, just zip tied on. They would hold the 20+ psi I ran on my SVO.
May 30, 2011 9:24 p.m. BoxheadTim SuperDork

I'll try to find those next then, I guess. I was hoping I could find some at the local O'Reilly but I guess I should check with Napa or Summit Racing...
May 30, 2011 9:46 p.m. turbojunker HalfDork

Look with the Help branded stuff.
May 30, 2011 10:13 p.m. 93gsxturbo HalfDork

Screw protectors from your local hardware store (thin, vinly)

Properly sized they wont blow off, or if they do, add zipties.

Most DSMs on the road are 90% zipties and 10% hopes and dreams anyway, go for it!
May 31, 2011 2:16 p.m. turboswede SuperDork

On my turbo-dodge vehicles, I use zipties on the the vacuum fittings. Even if they don't or haven't blown off, I view it similar to safety wire for fasteners.
May 31, 2011 2:20 p.m. Taiden HalfDork

Anyone got tips for testing for vacuum leaks? I'm about to tackle a bmw cluster-fudge of vacuum hoses.
May 31, 2011 2:23 p.m. bravenrace SuperDork

Didn't anyone tell you? You're not allowed to hate anything but sunroofs today.
May 31, 2011 2:25 p.m. 1988RedT2 Dork

I never had a problem with my turbo RX-7 until I got the bright idea of replacing all the old rubber hoses with that slippery silicone hose that comes in pretty colors. What a bunch of crap! It would pop a hose every time I drove it. Well, until I came to my senses and replaced it all again with new rubber tubing in basic black.
May 31, 2011 3:11 p.m. Ojala New Reader

Taiden wrote:

Anyone got tips for testing for vacuum leaks? I'm about to tackle a bmw cluster-fudge of vacuum hoses.

First thing I do is check the vacuum. If it is idling smoothly, pulling roughly the right amount of vacuum, and the fuel trims look good then I dont worry about it. If you do have a problem just look at the hoses for obvious loose hoses and cracks or breaks. Beyond that, for small leaks a can of starter fluid works pretty well.

I hook up my laptop and log rpm and fuel corrections. After that I just carefully spray vacuum hoses with the starter fluid and looks for changes. I wait a few seconds between sprays and remember the pattern that I used to spray fluid starting just behind the MAF and working to the cylinder heads at cylinder 1. Even if you cant log the engine data you can usually hear a change in the idle when the engine sucks in the starter fluid.
May 31, 2011 3:18 p.m. poopshovel SuperDork

Most DSMs on the road are 90% zipties and 10% hopes and dreams anyway, go for it!

SAAAAY WHAAAAAAAA!?