2stroke1971

Alright.
Generally speaking.....as far as removing the rats nest goes....(its an 85 with the 12A)
If the items I would be removing were not working properly, etc...it could contribute to poor running/performance, etc..right?

So I would imagine it would be possible to see an improvement from simplifying things....is this the general motivation for removing the emissions equipment or what?

A year ago when we got the car, I went through and replaced all the cracked up hoses i could find, etc...but Im having some annoying issues with the idle and subtle things about the way it runs...hard starting etc....

The car was my son's...but now Ive inherited it as he is done with it. (He bought a Honda) <cringe> lol.....I always said I would take it off his hands when the time came..Ive had so much fun test driving it after working on it for him..., and now I want to go through it and get it running as good as I can. (its got alot of miles on it)

ray green

iTrader: (14)

The purpose of the nest is to improve gas mileage and reduce emissions, both of which will suffer if you remove a properly functioning rats nest.

If you think the cause of your poor running/performance is the rats nest. it's not a lot of work to remove it and block off all the vacuum connections to see if this makes a difference.

However you may very well find the car still runs poorly or even worse, so I would hold onto it in case you want to go back to the stock set up. Reinstallation is a good time to make sure everything is working and hooked up right. When I reinstalled mine, I gained 6 mpg, smoother idling and much better throttle progression.

2stroke1971

Interesting! Thanks for the input. Seems like I should not be in any hurry to do that. I think I will check other areas first and not use that as a starting point. In fact one thing I am going to reverse already is the mechanical secondary mod I did to it. I hate that woof when they come on, I know theres a mod for the accelerator pump, but the vacuum actuator worked just fine. Now if I can just remember where I put the little link arm that was on the vac box.

ray green

iTrader: (14)

Yeah, I did the mechanical secondary mod too, hated it. That alone should give you another 3-4 mpg and much nicer progression.

I have the link if you lost it, just shoot me a pm and I'll get it in the mail.

NCross

iTrader: (18)

You wont lose Mpg if you do it right.

-Keep the orange solenoid for the trailing vacuum advance. Plumb it into the third nipple on the carb base.
-plumb the leading vacuum advance into the second nipple on the carb base.
-keep the TPS
-leave the float bowl vent open
- cap everything else off and remove everything not needed and store it in a box

ray green

iTrader: (14)

Thanks for the tips NCross, I'm going to try this again on the current project, maybe I just didn't do it right. Or maybe those mechanical secondaries were the real problem.

Removing the rats sure does make things a lot cleaner and removing the carb is much easier.

Jeff20B

iTrader: (13)

Ray, when you do the mechanical secondaries, you also have to do the Sterling accel pump mod. Not sure if you did that.

NCross

iTrader: (18)

Not enough volume in the stock pump. Vac secondaries do great if theyre functioning correctly. The main loss of power and MPG comes from not running the vac advance routing right.

Bori rx

iTrader: (1)

Ncross do you have any pics you can show?

NCross

iTrader: (18)

Trailing is routed through the solenoid to the third vacuum port under the carb. Leading is routed straight to the second port. If you trace your metal rats nest thats how it routes. Your just eliminating all of the unneeded bits.

Everything else minus the TPS and richer solenoid? Has been removed, and the electrical connector taped back into the harness.

rwatson5651

iTrader: (5)

Do you know how the second port and the third ports differ?

One question I have is how is the orifices inside the carb are situated to the throttle plate.

Or put another way, when do each of them see vacuum and when do they not.

I am interested in replicating this arrangement with my webbers, if possible.

Clean looking setup, btw......

Bori rx

iTrader: (1)

Thanks NCross
Your SA is beautiful, love the flat black engine bay looks sweet :-)

NCross

iTrader: (18)

Someone else can chime in here, but... i believe port three sees constant vacuum, port two only sees vacuum above X RPM. The solenoid opens the connection at a precise RPM or load for port three. Thanks for the compliment. Its actually truck bed liner. The original Aurora white in the engine bay had faded to a nasty almost Spark yellow color in spots where it was stained from oils.

Stevan

iTrader: (17)

Yep, and doing it right does not include mechanical secondaries mod.

However:
Leading and trailing vacuum are both supplied by the 2nd nipple, the 3rd goes to the purge valve in stock configuration. See photo.

The trailing vacuum solenoid cuts trailing vacuum advance below 2900-3100 rpm, you are saying this is going to increase mpg? I don't see it having an impact. Unless maybe you're flogging the gas pedal below 3k rpm trying accelerate? Enlighten me.
The TPS would only be there to control the trailing vacuum solenoid?

It's emission control equipment, not performance enhancing equipment.

NCross

iTrader: (18)

Mine is SA.1980. Perhaps its different routing than s2 and s3 right? I traced the metal piping, and the third port goes straight to the trailing solenoid. 99% positive. You may not need the TPS, its really just to prevent backfires im thinking. Its not hurting anything staying there. Without the trailing solenoid, you will run full advance below 3000RPM right? That would affect performance and MPG id think. Your MPG loss comes from the mech secondaries mostly. I had them on my Sterling several years ago. I averaged 18 MPG with them, but when i flipped the throttle linkage around to return it to vac secondaries, i increased MPG to 21.

Stevan

iTrader: (17)

The OP/thread starter has an 85. Anyway, going off a diagram (1980) in the Haynes manual the leading and trailing vac are fed from the same source.
I've never kept the TPS, and I haven't had any back fires.
Full advance w/o the solenoid below 3krpm? I don't think so. With the solenoid, when it opens at 3200 rpm, does it go to full advance? Looking at the diagram, it shows the vacuum source above the throttle plate making it venturi "I believe". So more throttle/rpm = more vacuum to advance. I remember a discussion about this a while back, I don't recall the outcome.

I've never done mech secondaries. It's quite obvious it would affect MPG.

ray green

iTrader: (14)

Thanks for the details dudes, I'm going to try going ratless one more time, sure does pretty up the engine bay.

NCross

iTrader: (18)

i have noticed that without the tps the enginge seems to gurgle and buck a bit more on decel. Nothing major, but noticable.