Will nozzle create a vacuum leak?

[disco stu]

Just got my SMC. Wanted to know, since nozzle can be blown through will this create an unmetered vacuum leak? At 15" vacuum couldn't this be sucking alcohol through the pump at idle? Can't see why not but I haven't heard of any problems related to this.

 

[Turbo__Tim]

It's a good thing to think about, but no you won't have any problems. If the alchy container is mounted below the nozzle you will be ok.

Nobody has reported a rough idle, for instance, after install. Just be sure the JB Weld has time to sit and seal well...

If you want to check for yourself, fill the alchy bottle to the top, and take a few good wot runs with the alchy system inactivated. The alchy level should remain the same if there is no siphoning going on.

 

[1badTTA]

Remember that if your nozzle is mounted in the uppipe then there is almost no vacuum. If it is mounted after the throttle body then you will have vacuum and need to pressurize/vacuum charge your bottle so it is at the same pressure/vacuum to prevent siphoning.

 

[disco stu]

Jeeeez, what was I thinkin, now I feel like a bloomin idiot. Thanks.

 

[blackbuick87]

My kit came with an anti siphon valve to prevent this. I am sure one could be added to yours

 

[disco stu]

Hmmmm, Will be awhile till I get my car running, but if I need an anti siphon valve when I do, where can I get one and how does it work?

 

[1badTTA]

You need it if your nozzle is mounted lower than your bottle. it will prevent the alky from siphoning into your intercooler. I believe it is just a spring loaded valve that wont allow flow unless you have some pressure behind it, someone correct me if I am wrong (which I never am, just ask my wife).