hi guys one for the ca18det experts, is there any gain in removing the factory throttle plates/system that opens up as the throttle is opened? it seems this system is causing my head to be full of gum and crap in the ports where these plates exist, just thought it may be worthwhile removing it all. pros/cons and advice from people who have done it please thanks andrew

Removing them makes no gains at all. I removed mine and pluged welded the holes up. Just a lot simpler without them less restriction and less moving parts.
Cheers Andrew

Yep remove them. Just weld up the out side holes.

apparently makes it run a little worse on cold mornings or whatever, but surely wouldn't be worse than the ol' weber...

can any1 post a pic as im confused at what part were talking about ?lol

It didnt run any different on cold mornings, but it helps them not gunk up so much around the intake runners.

if you take the standard intake off and look up the runners you'll see every second one has a butterfly type thing in it, one per cylinder. At low engine speeds this is almost closed so the engine pretty much uses one intake valve per cylinder or something.

Removing them loses about 10-20 ft/pd between 1000-4000rpm. I tested this on the dyno and played around with moving the RPM point at which they open, which was possible on the Autronic. Raised the level slightly because of my bigger cams.

For the complexity and expense, why would a big factory use such tecnology unless it had some real benefit. Most companies will do anything to save every dollar, because it translates to millions of dollars saved over a run of cars.

The cost in removing them only has benefits in your mind. So unless you are bored and have a tig welder, getting rid of them will only cost you money.

I too have noticed a little gum buildup, but that runner doesn't have an injector feeding it, so the gum is either blowby, or oil from turbo seals.

Hope this helps.

ps. After 250,000 kms, these may start to leak..it's at that time I would agree to remove them.

are u able to just take off the actual plates and leave the rod in there to save welding up the holes? i see this as a much simpler and easier way to get almost the same result, although i do realise the rod will still be there ...

yep thats what i would be doing. just for the less restriction factor, unscrew the throttle plates from the rod, it won't cost you a cent. i did this on my old ca18 only coz i thought it would be better at higher rpm without them in the ports. sounds like dattodude has actually done some testing tho.