August 22, 2016 1:42 pm - Published by

So if you’ve seen part 1 of the DIYTBs you remember this monstrosity:

There were unsurprisingly vacuum leaks galore from my hideous test manifold, and the throttles themselves were working loose from the vibration. I also had huge trouble because of the use of silicone hoses, especially such a large length and with a 45 degree angle, they were collapsing at idle, when vacuum is strongest, and pulling themselves off the throttles.

In my V3 system, support brackets were used to preload the whole setup and ensure that it didn’t vibrate in use- you can now rock the whole car with the throttle bodies, so I’d say that was a success! I also tried using O-rings in the original grooves of the throttles, combined with some enormous Mikalor W-clamps, but the grip wasn’t enough to stop the collapse pulling the hoses off the throttles, and I had to have another rethink.
V4 called for a better system. Some support rings were added inside the elbows of the ITB pipework, with jubilee clips on the elbow of the hoses, to stop them collapsing under the extreme vacuum at idle, and work very effectively, no more collapsing hoses and consequently, the sealing issues have also disappeared!


Now it runs properly, and makes all the right kind of noises!

So now that the setup runs and concept is proven, it’s time to tidy up the mess under the bonnet. I bought a proper vacuum block to link up all the throttles to, as well as the stock brake booster hose and the PCV system (which is one of my biggest pet peeves to see disconnected in most builds!!) through a catch can to filter out the excess oil from the system.

For the catch can I have a cheapy ebay one to modify and properly baffle, rather than spending triple the price on a premade one. The theme is DIY of course!

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