One of the many little idiosynchosies I must deal with with this turbo conversion is that my cruise control motor will crap itself whever the engine is under boost (positive manifold pressure!)

Does the cruise control accelerate deeply enough to get boost from the turbo?

OK- do you think a check valve in the vacuum line would be enough, or would I need a vacuum storage tank?

I don't really need it that badly, but it would be nice.
It really makes long trips easier....

 

you need to replace the cruise control body with one from a T2. They are electric, rather than vacuum driven

 

Yep, I'm aware those are electric- but would they use the same signals from the CPU? Just a straight swap with the motor? (plus wiring of course)

 

Straight swap, yes. I should have one or 2 lying around, $40 each. Plug and play.

hypntyz@charter.net

 

It's a straight swap. However, you probably don't need to swap if you do not use the accel button on the cruise. I swear that the damn thing goes WOT when you hit that button...Personally, I'm not worried about it...Though the cruise may get VERY confused if you try to set it under boost....

 

I couldn't get my vert T2 conversion to go up steep hills with the vacuum controlled cruise. I had to use the electric controlled one.

 

How about tapping into the brake booster line on the other side of the check valve??The side away from the engine. You did put in a check valve for the brake booster? Just a thought.

 

Hmm- good call- Do the turbo's have a check valve in the brake booster???
Could be internal... I've never heard of anyone having to do that- but it's definatly worth looking into!

 

Ah the electric one is better anyway. No internal diaphram to fail and leak

 

Electrics just fine. The turbos do have a check valve in the line about six inches from the booster. Inline. Still, forty bucks....and no tinkering.......yeah, go electric. Then again if you like to tinker... And shouldn't you have the check valve in the brake booster line if you swapped over to turbo? For safety????

 

I hadn't thought of tapping in on that line, but that makes sense.

But the check valve seems to be rather common on CA cars. Every FC I have owned has had it weither or not it was a turbo. My 88 'vert had it in line already, before the conversion.

In fact on my old 87 Sport I had replaced the line with a stainless braided line and accidentally removed the check valve and had weird pedal feel until I put the line with check valve back in.

 

Yeah. I'm kinda sorry I mentioned the check valve thing. I remember reading a post about how to swap a turbo to a N/A and I would have sworn the article said something about making sure the turbo's brake check valve was installed when doing the swap, but I have spent the last thrity minutes looking at old posts about swapping engines and have come to the conclusion one of my marbles has fallen out. Probably any car with a brake booster has a check valve. Just an incorrect thought caught up in my head that didn't go away. Go electric. Forty bucks is cheap, cheap. Can't wait until the morning so I can see about the 20.000 mile switch thing mentioned on another post. My milage is something like 200,400 on a used insturment panel in my car, so I'm chaffing at the bit to see if my port air solenoid is configured to the pre 20.000 mile setting.

 

There is a check valve installed in all RX-7s (or maybe all cars?) for safety. If the engine dies, the valve maintains enough vacuum in the boosted for a few safe applications so you can safely stop with the power assist.