CRG Discussion Forum

Camaro Research Group Discussion => General Discussion => Topic started by: jonboy1216 on August 04, 2009, 05:44:22 AM

Title: vacuum required to run power brakes and ac and rs doors on a 68
Post by: jonboy1216 on August 04, 2009, 05:44:22 AM

how much vacuum does it take to run air conditioning,rs headlight doors,and power front disc brakes with four piston calipers?

Title: Re: vacuum required to run power brakes and ac and rs doors on a 68
Post by: JohnZ on August 04, 2009, 02:25:42 PM

Most Z/28's only pull 9"-11" Hg. of vacuum at a 900 rpm idle, and all had power disc brakes; not ideal, but all were built that way. Hydraulic-lifter engines typically pulled 15"-18" Hg.

Title: Re: vacuum required to run power brakes and ac and rs doors on a 68
Post by: Mark on August 04, 2009, 04:06:45 PM

You have vacuum cans for each of those systems so it really doesn't matter how much vacuum you run, the booster, a/c canister, and the RS canister will all trap the highest vacuum they see, such as under deceleration and hold it as long as your systems are tight.  I can close my RS headlights 30 seconds after i shut the engine off, and my brake booster will still have vacuum in it days later.

Title: Re: vacuum required to run power brakes and ac and rs doors on a 68
Post by: jonboy1216 on August 05, 2009, 03:19:35 AM

thanks guys for the info          so if i have at least 9-11 hg with a new cam im good for a weekend cruiser right?

Title: Re: vacuum required to run power brakes and ac and rs doors on a 68
Post by: JohnZ on August 05, 2009, 03:45:29 PM

Quote from: jonboy1216 on August 05, 2009, 03:19:35 AM

thanks guys for the info          so if i have at least 9-11 hg with a new cam im good for a weekend cruiser right?

Yup - all Z/28's were like that.