Confusion about a vacuum source

[supraguy@aol]

I was searching 'vacuum' threads, but didn't find my answer;
I have an 88' 7mgte(swap), and was wondering how to set up a vacuum manifold. Is there a particular port that I can tap into, or do I have to use two different ports with check valves, so that I can get vacuum under light throttle as well as boost? I'm trying to get my cruise control to work(it's from an NA), and I realize that if I just hook up to vacuum post-throttle body, I'll lose vacuum as soon as the CC tries to throttle up the motor. If anyone has any experience in this, please chime in.
Thanx.

PS- using an eagle vac. manifold.

 

[jetjock]

The GTE CC system has a vacuum pump and a switch to control it. You may want to obtain them. I believe the CC box and harness is the same on both cars but don't hold me to it.

 

[Dan_Gyoba]

Having just swapped a 7M-GTE into my '89NA...

1. The CC system will work, as-is. This is what I'm currently doing. The engine has to remain under a bit of vacuum in the manifold, but not much. It loses a bit of speed on the uphills, but overall, it works pretty well.

2. The GTE system has a vacuum pump. In the GTE car, it's located along a nest of vaccum lines near the brake booster, near the turbo pressure sender (For the dash gauge) Unfortunately, there is no wiring harness for the pump in the NA's wiring harness, so you'll have to wing it. I would recommend that you use a vacuum pressure switch, so that when there's manifold vacuum, the pump is off. This conserves the life of the pump by only running it when there's a need for boost under cruise. This should not be for prolonged periods, unless you set your cruise at 125mph...

 

[IJ.]

My 86.5 has a pump stock.

I also use the ACIS Reservoir plumbed into the CC circuit as the bigger cams don't make as much vacuum and on long uphills my motor would come on boost under CC and the pump couldn't keep up.

 

[jetjock]

A vacuum reservoir/accumulator should work. Would be far from the first car to have one. Piece of PVC pipe with end caps would do and fit right in with some of this gang. Remember the climate control dampers and wipers from the old days?

 

[IJ.]

JJ: Shhh you're showing our age

Vacc wipers were a PITA for sure!
(big rev and the wipers would stop)

 

[supraguy@aol]

Thanx for the replies. Yes, I have a turbo model of the CC as well, but due to the fact that (as mentioned above) there is no wiring plug to actuate the pump motor, I wanted to use the NA version. Not sure HOW I would trigger the GTE CC vac motor, as mentioned above, so again, Is there a single place to hook up an Eagle vac manifold, or do I need to use two ports- one pre-turbo and one post TB- with one-way valves, in order to assure continuous vacuum? Or am I overthinking this?

 

[cuel]

Meh, work on one of the old Mercedes diesels some time. Everything is vacuum operated, including door locks and part of the ignition switch circuit. That'll make you tear your hair out, and run around in a hysterical fit. Plastic vacuum tubes in the doors, door sills, all through the dash, every-freaking-where. That was at the first mechanic shop I worked at, and was one of my first cars. I wanted to kick my shop foreman in the nuts for putting me on that car. He owns the shop I work at now. Think I'll kick him tomorrow...

Sorry to jack your post. I'm bored....

 

[jetjock]

If it were me I'd wire the pump and switches in. Since they connect directly to the CC box it's simple wiring. Otherwise I'd install a vacuum accumulator. Or accept what Dan said. Seems to work OK for him.

 

[shaeff]

A vacuum reservoir/accumulator should work. Would be far from the first car to have one. Piece of PVC pipe with end caps would do and fit right in with some of this gang. Remember the climate control dampers and wipers from the old days?

my bro has a partially restored '52 chevy pickup. when you stomp on the skinny pedal, the wipers momentarily stop. it's quite entertaining.