Pretty sure it's the opposite... The inside port does vacuum retard. Outside port is vacuum advance and boost retard, at least on my 88 930...

The valve is the boost side, outside port.

When you blow into the boost trigger line, when cold, no air flows past this valve. When warm, it does...

Yep, sorry. I was thinking of something else. Here is the whole horrible story of how everything works, if you can stand it.

http://forums.pelicanparts.com/uploa...1462167520.jpg


Figure 1 – Throttle body port connections

Referring to Figure 1:

I - This is ported vacuum. The port is about 2mm BELOW the throttle plate when the throttle is closed. It has vacuum from closed throttle (idle) to about 1/3 open throttle, and it has pressure under boost. A hose goes from this port goes to a solenoid valve that, when not powered, vents the back side of the distributor capsule to atmosphere. It comes from the factory with a Blue hose.

II - This is the same port as I. A hose goes from this port to a solenoid valve that, when not powered, connects port II to the air injection control valve. Another hose connects port II directly to the catalyst air injection valve.

III - This is straight manifold vacuum. It is not ported. This port is connected to the vacuum limiter valve. It also has pressure under boost.

IV - This is the same port as III. This port is connected to the warm-up regulator.

V - This is ported vacuum, but a different port. The port is about 2mm ABOVE the throttle plate when the throttle is closed. It has no vacuum at idle. When the throttle is opened a small amount, it has vacuum from that point to about 1/3 throttle, and it has pressure under boost. This port is connected to the thermo switch (non-electrical), and from there to the front side of the distributor. It comes from the factory with a Red hose.





Here is how it works:

Idle (cold start) - There is no vacuum to the front side of the distributor from port V because the throttle is closed. The solenoid valve for port I is turned OFF, so there is no vacuum to the back side of the distributor capsule from port I. The solenoid valve remains OFF until a temperature switch in the oil flow reaches 35C. With no vacuum on the back of the distributor capsule, timing is advanced and the idle speed is elevated. The solenoid valve for port II is also turned OFF, so the air injection control valve is turned on. There is vacuum from port II to the catalyst air injection control valve, causing it to inject air. Ports III and IV see manifold vacuum. The vacuum limiter limits the manifold pressure to about 22 kPa to stabilize airflow. This helps the O2 sensor/frequency valve maintain air/fuel ratio at 14.7. Port IV operates the warm-up regulator.

Idle (warm) - There is no vacuum to the front side of the distributor from port V because the throttle is closed. The solenoid valve for port I is turned ON once the oil temperature reaches 35C, so there is vacuum to the back side of the distributor from port I. This retards the timing at idle to reduce NOx emissions, and the idle speed is lowered to the warm idle speed (~950 RPM). The solenoid valve for port II is also turned ON, so there is no vacuum from port II to the air injection control valve, causing it to stop injecting air into the exhaust ports. There is vacuum from port II to the catalyst air injection control valve, causing it to inject air. Ports III and IV see manifold vacuum. The vacuum limiter limits the manifold pressure to about 22 kPa to stabilize airflow. This helps the O2 sensor/frequency valve maintain air/fuel ratio at 14.7. Port IV operates the warm-up regulator.

Part throttle (no boost) - There is vacuum to the front side of the distributor from port V, after the thermo switch has opened. It advances the timing. The solenoid valve for port I is turned OFF so there is no vacuum to the back side of the distributor from port I. The solenoid valve for port II is also turned OFF, so there is vacuum from port II to the air injection control valve, causing it to inject air into the exhaust ports. There is vacuum from port II to the catalyst air injection control valve, causing it to inject air. Ports III and IV still see manifold vacuum, but it is reduced due to the open throttle. This makes the vacuum limiter valve close, and the warm-up regulator may use the sensed manifold vacuum to enrich the mixture for accelerations, for instance.

Part throttle (boost) – Past about 1/3 throttle, there is pressure to the front side of the distributor from port V, after the thermo switch has opened. This retards the timing. The solenoid valve for port I is turned OFF so there is no pressure to the back side of the distributor from port I. The solenoid valve for port II is also turned OFF, but now there is pressure from port II to the air injection control valve, causing it to stop injecting air into the exhaust ports. There is also pressure from port II to the catalyst air injection control valve, causing it to stop injecting air. Ports III and IV see manifold pressure. This makes the vacuum limiter valve close tightly, and the warm-up regulator uses the boost pressure to enrich the mixture.

Full throttle - The whole system is under pressure. Port V sees pressure and applies it to the front of the distributor capsule, so the timing is retarded. The solenoid valve for port I is turned OFF, so no pressure is applied to the back of the distributor capsule. The solenoid valve for port II is also turned OFF, but now there is pressure from port II to the air injection control valve. The pressure from port II holds it closed so no exhaust pressure back-feeds into the air pump. Pressure from port II also keeps the catalyst air injection control valve closed, so no air is injected under boost. Full manifold pressure from port III holds the vacuum limiter valve closed, so no boost pressure can leak out of the intake manifold. Port IV is pressurizing the warm-up regulator, causing it to enrich the air/fuel ratio.

Decel - There is no vacuum to the front side of the distributor from port V. The electrical on/off switch is turned ON so there is vacuum to the back side of the distributor from port I. This retards the timing at idle. The solenoid valve for port I is turned ON, so there is no vacuum from port II to the air injection control valve, and no air is injected into the exhaust ports. There is vacuum from port II to the catalyst air injection control valve, causing it to inject air. Ports III and IV see manifold vacuum. The vacuum limiter limits the manifold pressure to about 22 kPa. This helps the fuel from the continuous injection to burn in the cylinder, and thus prevents the popping noise in the exhaust. Port IV operates the warm-up regulator in a way that minimizes the amount of fuel injected.

http://forums.pelicanparts.com/uploa...1462167564.jpg


http://forums.pelicanparts.com/uploa...1462167712.jpg

This is awesome Speedy...thank you

The bottom line is that, without the thermo valve. You get the advance from the high idle, and the advance from the throttle on tip in. That much advance on a cold car, with stock timing otherwise, usually causes a stumble when you tip in. Once the 35C switch activates though, it goes away.

Thanks guys, decided to leave the switch in...

It is interesting though, as the same switch allows boost pressure retard... And until it open, you have NO boost retard...

So, with a cold motor, if you get it on boost, you have 26 degrees of advance and full boost...

Why aren't motor grenading left and right?

Because you can run 26 degrees of advance on boost, just like every 930 with a Euro dizzy does. If it grenades it is because you boosted a cold engine ...

The USA timing is pretty belt and suspenders conservative. Plus, the thermovalve opens pretty fast, especially under load. I think you would be hard pressed to catch it closed with full boost.

I am now officially confused... I thought everyone posted in this thread that under boost you are at 16 degrees... Euro or not...

Are you saying it's possible to run a 930 with no boost retard?

Yep, common even. The Euro engine is the same basic engine, but it uses a single vacuum canister on the distributor. It runs 31 degrees at WOT on 89 RON Euro fuel, which is roughly like our 93 R+M/2 fuel.

The Euro dizzy has no retard on boost. It has one pot and that is for idle. I plug that one, set the idle manually, and set the timing at a conservative 26° for 89 octane fuel in the Alabama heat. I've talked about this before but it gets lost in all the talk of the more complex (and crappy) USA distributor function.

I really don't want to go through 27 pages of this, but you're saying Porsche used 31 degrees at 0.7-0.8 bar of boost with 93 octane?

Just looking for a safe timing data point.

The workshop manual lists 29° @ 4000rpm for the Euro 930, however I use 26° so I can run 89 octane gas in the Alabama summer.

The USA model 1987 911 turbo has a small mechanical thermal valve in the vacuum advance hose. It's an emission device.
It blocks the vacuum advance line from reaching the distributer's vacuum advance pot until engine heat soaks into it and opens it allowing vacuum advance to work.

Exhaust temperature is hotter when ignition timing is retarded because the very last of the gas mixture in the combustion chambers is still burning or just finished burning when the exhaust valve opens.

This thermovalve's purpose is to keep ignition timing in the USA cars slightly retarded after a cold start so the catalytic converter heats up faster.
Getting the CAT up to operating temp faster lowered exhaust emissions so they could sell these cars in the USA again starting in 1986.

And just to be clear, there's no boost retard from 29?

There is no boost retard on the Euro dizzy. That and the more aggressive timing curve are why I like to use the Euro ignition distributor, it helps the Euro engines achieve a rating of 300HP. I ran one on the Red Rocket for 15 years with the idle vac pot blocked off and timing set at 26°. The stock USA distributor was tossed along with the other 100lb of emission garbage.

No boost retard on 29 +or- 2 actually.

Thanks Speedy and Brian!

I'm bumping this thread in the hopes that someone might be able to comment on the potential usefulness of the new programmable CDI boxes that are offered. I am having some trouble with the tach feed of my CDI box since I've connected it to a MSD RPM window switch for the boost delay. I was going to go ahead and get my box and original distributor rebuilt. However, if there are advantages to the programmable unit, then I'm happy to go in that direction instead.

https://www.************.com/p-2059-cdi-programmable-six-pin.aspx

A few questions for those that understand these things:

1. In order to use the programmable box and software defined ignition curve, are the normal advance and retard functions of the stock distributor disabled?

2. Would there be an 'optimum' ignition curve that could optimize power and boost response?

3. Does it look to y'all like there is a way for the box to sense boost?

Thanks very much for any input that you might have. I'm planning to call Kurt at PK but would appreciate other opinions (wishfully including Cole's).

Thanks!

If that's anything like the quality of their distributor rebuilds (or "the electronic WUR they're peddling)... :eek:

We have an alternative for you Turbo guys. Gaining quite a following in the UK amongst engine builders.

CDI+ is Plug and play, multispark to 10000 RM, soft and hard limiters, fully mapable.

Bosch CDI replacement and classic car fuse panels

Available on Pelican, search '911-CDI'

Hi Jonny,

Thanks for your reply. Your CDI box looks like it is very well thought out. The question I had is whether the box can detect boost so that the boost-retard can be programmed in.

If it doesn't, how would you suggest managing that?



Sent from my iPhone using Tapatalk

We have a spare input on the unit that could be used to reduce advance or switch to a different map.

Do you think the boost retard needs to be proportional to boost or can it just be a on/off based on going over a certain pressure?

I also wonder whether boost can be detected based on the rate of change of RPM. In other words, could retard be applied based on RPM rising at a fast rate?

Distributor green wire source?
 

I need to replace the green wire on distributor. Can anyone point me to a supplier?http://forums.pelicanparts.com/uploa...1481768163.JPG

Our host may still stock them. It is the same wire for later 911SCs and you can even use the 928 wire, tho it is much longer. If no luck with host, eBay or any variety of aftermarket source. I might note when I last needed one there were large variations in price. Good hunting.

Distributor Signal Cable 93060290701 - Bosch - Porsche - 930-602-907-01 | Pelican Parts

Pelican has both "Porsche" and Bosch. There is no way I would pay the Porsche tax for what amounts to the same wire.

Yowzer,
That's about $14 an inch.
Thank you for the help.

As an fyi, you could just splice the wire...

Its coaxial. Splice the internal wire, and then the external. Works just fine. Then shrink wrap.

This is a great question. I think the plunger action on the OEM vacuum can is more analagous to a progressive analog switch rather than a digital on/off type switch. However, it may not matter if the rate of boost rises quickly enough.

It would likely be hard to detect boost on the basis of the rate of rpm change. It would probably be easier to detect boost if you use something like a Hobbs switch. The nice thing about the Hobbs switch is that you could set the boost (ignition map change) threshold.

As far as the rate of ignition retard relative to boost, I have absolutely no idea. Hopefully one of the smarter guys (TK?) can give us an idea what would be best.

Thanks

Could that input be controlled with a MSD 8762 boost timing controller? It uses the boost signal to retard timing. Here is a link to the wiring instructions if it's used with a MSD ignition.

http://documents.msdperformance.com/8762.pdf


Rawknee told me this guy charged him $10,000 and inch.

SoCal Phalloplasty, Penile Enlargement Surgery, Penis Lengthening and Penis Widening with Alloderm, Glanular Enhancement, Reconstructive Surgery by Renowned Beverly Hills Phalloplasty Surgeon

Actually Deez, that charge was for reduction surgery, so the wimminz would no longer be so intimidated and afraid (paying for custom made pants was getting old, and expensive, too)!!!!

^^^^^

Yep, Knees is the man!

http://forums.pelicanparts.com/uploa...1481914632.gif

It should be proportional to boost.
Ideal would be to have it be MAP-based, signal from the throttle body "T" where the WUR gets its signal.

Thanks TK. A MAP sensor is on our roadmap for the CDI+ product.

Any update on this MAP sensor on your roadmap?

If you only need a MAP sensor I have several very cool 3bar billet sensors made in Finland. 50eur for one or 90 for two.
https://drive.google.com/file/d/0B6RqXGaH_zSUZUM1bTdwX0tkbmc/view?usp=drivesdk

Thanks for the offer Ola. Actually I'm just now re-starting my 930.62 engine rebuild project and checking the options for the ignition (among the other things).
The current distributor is for some reason 0 237 302 009 (PGFUD6(L) 3.3 Cal (1/78-6/80) 930.63).
PET says that the original has been 0 237 301 006 (PGFUD6(L) 3.3 Japan 930.62,65)
I have also 0 237 302 034 (PGFUD6(L) 3.3 RoW (MY 83-) 930.66) that I could use.

With this CDI+ I could use the current 0 237 302 009 distributor and just replace CDI with CDI+. All would still look just like original.
But how to handle boost?

Status of my engine project is that it has been boxed for few years with all parts cleaned and the mechanic (=me) has been waiting for the inspiration. New plan could be that maybe I could get it running 2020.
What I already have is K7200 + Fabspeed heatexchangers + Blown6 IC + SC cams. Other than those I plan to keep the engine looking like the original - CIS will remain.

Speedy- snipped your excellent post to ask a question specifically about the part I underlined- “The solenoid valve remains OFF until a temperature switch in the oil flow reaches 35C.”

I’m trying to return my disconnected solenoid into service but I’m not sure I have the wiring integrity to do so. My 1986 930’s lambda O2 sensor is long gone, and the solenoids for the distributor and air pump came in the glove box when I bought the car.

Where is this temperature switch? I assume it’s the one on RH timing cover with single green wire to it.

In testing with engine off, fuel pumps running, stone cold engine, I have 0.02V to the solenoid connector. Not sure why. This is your Idle (cold Start) scenario below. Connecting the solenoid to the wire results in the solenoid staying off.

When I jump the wire on the temp switch that voltage reading goes up to 0.03V. I would have thought this would simulate your Idle (Warm) condition and open my solenoid. It does not. Connecting the solenoid to the wire resulting to start solenoid still being off.

Do you know of another way to jump something to simulate Idle (warm)?

ou will need to have the Fuel Enrichment Control Unit still in place and operational. it is located under the front seat. The distributor mounted control capsule will need to be still functional. The solenoids must both be still on the car, and plugged in.

Step 1 - Test distributor mounted control capsule. Connect the blue hose from the back side of the capsule directly to Port I on the throttle body. The idle should go up when the hose is disconnected from the distributor capsule and plugged. It should go down when re-connected to the distributor capsule. It his test fails, there is no point going on. The capsule has failed and is NLA.

Step 2 - If Step 1 passes, reconfigure the blue hose to the correct arrangement, from Port 1 to solenoid, and from solenoid to the back side of the distributor capsule. Disconnect the solenoid connector. Use a jumper wire to ground one pin on the solenoid to the engine (does not matter which one). Apply 12V to the other pin from some source like the rear heater fuses. Removing and connecting power should make the idle speed go up and down. If not the solenoid will have to be replaced.

Step 3 - If steps 1 and 2 pass, disconnect the Green/Yellow wire from the 35 C thermoswitch in the front left chain housing cover. Connecting/disconnecting the wire to ground should cause the idle speed to jump up and down. If it does not, there is a problem with the Fuel Enrichment Control Unit, or the wiring to it. That is a more complex diagnostic job not coverable in a post.

Thanks for the detailed instructions.
So, I can confirm both sides of my vacuum can hold vacuum and alter the idle when mityvac’d.
Step 1 passes.
Step 2 passes.
Step 3 I will try to reproduce this weekend. If you didn’t mis-type, you mean that I should disconnect the switch from the front left chain cover, which is very hard to access with the turbo piping coming and going right there. I believed that thing was strictly for the cold start injector and fed power during starter cranking only. Perhaps I was wrong, and your test is free. I will report back.

PS- you also specifically noted that “The solenoids must both be still on the car, and plugged in.” That is NOT my case at the moment, but I can and will pull the intercooler again for the 200th time and reattach the air pump solenoid and wiring to that solenoid just in case the computer under the seat needs to feel it on the wiring.

PPS- right now I’m driving around with the blue hose solenoid plumbed in as factory and plugged in. My timing is roughly 10 BDTC now at idle because of that retard being blocked off by the solenoid, and I’m not sure if it ever opens right now. Thus step 3 test...

I can actually detect a double advance about a minute into a cold start when I assume the thermostatic switch in the breather cover opens and permits vacuum to the other side of the vacuum can. The idle rises a few hundred immediately.

I use a Classic Retrofit CDI +
 

My backdate 77S is fitted with a 79 930 drivetrain.
I shortened the 4 speed 27 mm to fit the chassis.

I use a Classic Retrofit CDI + and have CIS.

https://youtu.be/qHa47pvX1Kw

My OE distributor is set to make 24-26 degrees timing advance at idle up to redline. My vac retard is capped, boost retard is obviously connected and works.

So 0 degrees on the chart is reallly 24-26 degrees advance. This is their "Overlay" function which will allow boost retard to operate. I can still add or subtract timing under boost retard if I wish.

I'm pulling down timing at idle then adding some advance before boost comes on. after 4000 rpm I'm retarding back down to 24-26 degrees advance and my dizzy pot retards on boost as designed.

"Bandit" runs very well, AFRs look good. I run 1 bar sometimes 1.2 bar boost, many times 1.4 bar boost due to my Turbosmart boost controller not doing it's job. I have only a .7bar spring installed and the manual boost controller set all the way down. My Autometer Vac/Boost gauge pulls input directly off my brake booster. AFR at idle about 11, off idle 14-15, boost 11ish.

I use 93 octane and add either Lucas or Sea Foam brand injector cleaner to lubricate the injectors and add octane (according to the bottle) I just add a small amount every time I top off the tank. My motor has custom headers (uses euro CIS) i kept my Mahle pistons but added CP rods, welded the oil scavenge drive off my stiock cam to my NOS 964 cams, K27/7200, TiAl, big 964 style I/C. I opened up the intake manifold and heads 4mm. I cannot complain about performance.

Does anyone else run these injector cleaners, I use them always. I have new 009 injectors, I tested flow rates.

Matthttp://forums.pelicanparts.com/uploa...1656857122.jpg
http://forums.pelicanparts.com/uploa...1656857122.jpg
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Bandit is all steel and uses a lead acid batt and weighs 2150 with 6 gallons of premium.