I've been trying to get a real world example of one of the distributors used on the 930 with validation on a distributor machine of the actual capability as it comes from the factory. I also requested an opinion on what settings should be used for safe operation in a street driven car. This was done by one of the most respected Porsche gurus in the business.

Porsche Engine Type 930/60 from 1980 Row 930 Dist. PN# 0-237-301-004
CCW direction and single hose vacumme retard cannister. Factory Stock

Factory Timing Spec.:

29* BTDC @ 4000 RPM (Vacumme hose disconnected)

0* +/_ 2* @ 1000 RPM ( Vacumme hose connected)

Dist. Machine Data:

Vacume Retard:

4*- 5*ATDC (distributor *) @ Idle RPM with vaccume connected

5* BTDC (distributor *) @ Idle RPM with vacumme disconnected and pluged.

Note: 4*- 5* (distributor degrees) is 8*- 10* (crankshaft degrees)


Centrifigual Advance:

8*- 9* BTDC ( distributor *)

Centrifigual advance starts at 700 RPM and is all in at 1700 RPM (dist. shaft RPM)

Note: 8*- 9* (distributor degrees) is 16*- 18* (crankshaft degrees)



First we should note these suggested setting should be used with the following in mind:

Peak torque of this engine is at 4000 RPM and that is where boost is near it's peak, consequently this is the point of maximum pressure and where detonation is most likely to occure. At pre peak boost levels you are relatively safe because of the engines low initial compression ratio. To help prevent detonation the following mods should be considered. No more than 7 to 1 compression ratio, larger intercooler, free flow exhaust, correct afr's for the boost level you are running, and 97 octane fuel.

Suggested settings: (Assuming you are wanting to run .9 - 1.0 Bar boost)

With vacuume retard connected: At 4000 RPM timing at 26*BTDC timing should be retarded 4*-5* at 4000 RPM. ( This is assuming you have checked your vacumm retard and retard does not exceed 10* BTDC)

With vacumme retard connected and using MSD Boost Retard: At 4000 RPM timing at 29* BTDC pull .3*- .5* per PSI of boost

With vacumme retard disconnected and plugged and using MSD Boost Retard:
Set inital timing at 10*-14* BTDC and total timing 29*- 32* BTDC, pull timing equal to a total timing of 24*- 26*BTDC. With this senario it allows you to play with initial and total timing to get the best low end response while maintaing good cruise and maintain 24*-26* at 4000 by adjusting MSD Boost Retard.

Cole

Cheers, Cole.

Interesting stuff!

Funny you posted this... I just took a break from wiring in an MSD 8762 boost retard box into my car.

My car is an '87 with the dual pot distributor so I'm not sure how your numbers correlate to it.

Mark Houghton has already done this on his car and I think he has the same distributor thats on mine.

I'm curious where you guys set the threshold or start control on the box and where you set the retard knob that mounts in the car.

Also do you guys attach a small degree wheel to the crank pulley or use a timing light with the advance knob to figure out what you're setting your timing to?
The pulley on my car only has marks at 0* and 26*BTDC.

thanks,
Jim

Cole,

Your info offers validation:

Total mechanical advance apx 18 deg.

Total mechanical advance all in by 3400rpm (1700 at dist x2).

Total vac advance (euro dist) apx 9 deg.

(Two pot gets apx 9 deg of advance from loss of vac-retard function.)

Euro single pot works opposite of dual pot. Euro single pot advances, two pot retards. Both equate to about 9 deg of advance or retard.

Single pot is timed hooked up to achive max total advance before 4k.

Dual pot is timed with conections removed to achive max total advance before 4k.

Recomendation for -26 is consistent with Bruce Andersons recomendations in his book on modifing Porsches. His recomendation being -25 if running .9 bar on the track or 1 bar on the street with intake ports, larger IC, sport muffler, better turbo.

This puts total advance on boost at apx -16 to -18 (that is -26 + 8= -18 and -26 +10=-16).



This is a little hard to follow. Single or double pot dist?

Bassically, what ever addational timing one wants to add of idle has to be taken back with the MSD. If total 5 deg of total timming is added taking total advance from -26 to -31. The MSD needs to pull that much. Thus, 5 deg divided by 14.7 (1 bar) is about .34 deg per pound that needs to be pulled.

Just use the factory timing procedure for the type of pot/dist.

----

Just my opinion but I might add:

MSD function all by its self is a positive modification on a CIS 930 helping to ensure firing of less than ideal AFR's.

Using MSD retard on top of factory retard is a valid approach. However if setting the knob is how this is done, accureate settings ( i.e. .34 deg per pound of boost) may not be easy to achive and subject to un-intentual change.

I have simply offered this information as a "real validation" of what the the single pot euro distributor is set up to provide in the way of vacuum advance/ retard and centrifugal advance from the factory. I felt this might be useful to others, as so far, we have had nothing other than guesses, opinions, and conjecture as to how these distributors really work. I had the distributor put on a machine because my engine is not back in the car yet so the distributor was available to be sent out and could provide helpful information to all of us.

In reference to the proposed settings I included, they are what I was told by the very highly respected tuner who spun my distributor for me. He has forgoten more about Porsche timing than any of us will ever know. You can take them or leave them, I happened to find them helpful and hoped others would also.

Regarding my timing references using the MSD Boost Retard: I have approached this knowing 1 important thing, it will allow me to retard my timing on boost to keep my motor from exploding while I work out the optimal initial and total timing settings for my car. As far as I know 20* BTDC may be the right initial setting for best low end responce and that accumlative 38* total mignt give me the best cruise, if it happens to be, I can still pull out 15* on boost with the MSD and save the motor. Try that without the MSD. As far as the reference to .3*-.5* per pound of boost retarded is concerned you can take out all 15 * of retard in the first 3 lbs. of boost if you wan't. If this information works for great. If it doesn't don't use it.

Jim:
I use a timing light with a advance wheel, RPM, and strobe, I found it helpful in that you can run the motor and look at the curve at any RPM as well as add compressed air to the MSD Boost Retard units boost tube and watch the effect.

My motor has a machined double groove pully which accomadates the fan and AC belts. The flat between the 2 grooves is stamped with several degree indications, I can't remember what all they are. But a degree tape is very helpfull and you can get one from MSD if you know the pulley Dia.

The start point to pull timing can be anywhere between 0 and 5 lbs. of boost
I would start relativly early untill you get a feel for when boost is starting in relation to degrees of timing and RPM. Keeping in mind my max cylinder pressure is at 4000 RPM.

Hope the Boost Retard install went well. You need to get with Mark as he does have the same distributor as yours. Mark has this timing pretty well in hand and he is always a great resource.

I added a couple pics of the MSD boxes placement, where I put the degrees of retard knob, and where I terminated the wiring with a 6 pin conn. that plugs directly into the engine harness.

TJ,

Hope you found it helpfull. It's nice to have some of this info available because it helps clear up some of the confusion.


http://forums.pelicanparts.com/uploa...1256439310.jpg






Cole

Sorry Jim,

I lost the last 2 pics.

http://forums.pelicanparts.com/uploa...1256441709.jpg


http://forums.pelicanparts.com/uploa...1256441731.jpg


Cole

I have done some research into the distributor numbers and found some info I thought I should share. If I could read German I could make sense of some of the numbers but here goes anyway.

Previous posts some stated their dizzy numbers were 0 237 302 045.

Mine is 0 237 302 034.

Reading the Bosch archives shows:
0 237 302 009 PGFUD6(L) was for Californian 3.3l (listed as from 1/78 till 6/80)
0 237 302 034 PGFUD6 (mine) I presume ROW/Euro (listed as 1982 onwards)
0 237 302 045 PGFUD6(L) was for US 911 Turbo

The only difference listed in the specs between mine and the US dizzy is 11.82 compared to 11.85 which seem to be the years they were used from?? otherwise they seem identical??

Also for your reference earlier cars (and by the looks 1-hose pot but can't confirm) were:

0 237 301 001 PGFUD6(R) 3L
0 237 301 002 PGFUD6(R) USA/Canada
0 237 301 003 PGFUD6(R) Japan
0 237 301 004 PGFUD6(L) Europa/ROW (listed as from 10/77 till 9/82)
0 237 301 005 PGFUD6(L) US (listed as from 10/77 till 6/80)
0 237 301 006 PGFUD6(L) Japan Export

I am wondering if the R and L in brackets after the part number determines the rotation ie clockwise or anti-clockwise but cannot confirm as my dizzy is anti clockwise and is the only one that doesn't have a letter after the PGFUD6......

Stole this from another thread. Believe this is a well tuned, EFI, twin plug motor. I suspect with twinpluging less advance is needed pre boost and about the same on boost.

Another one worth stealing:

I'm pulling 1.5* for each 1.0 PSI, with the starting threshold at 1.0 psi. With 8 degrees of advance that I added at idle, my goal was to pull all of that out by the time I hit around .3 bar (don't ask me why I chose .3 bar, just sounded like a nice place to start). So I'm actually pulling out 7.5 degrees by the time I hit 5 psi. And beyond that, the MSD will continue to pull 7.5* more timing off as boost builds beyond 5 psi to a maximum total of 15*, so technically/theoretically I should end up with 7.5* less advance at full boost than original stock settings.

In other words, by pulling so much out so early on, one pays the price in that more is pulled out as boost continues to build beyond your set point. So I ended up with less than optimal advance on full boost...very safe for 92 octane, but possibly leaving some performance on the table.

What I've just done last weekend to limit the additional retarding after 5 psi, was to intall a pressure regulator in-line with the boost line to the MSD, and set it to regulate 5 psi. With it, I still shave off the 7.5* by 5 psi, but with no increase in pressure beyond that the MSD stops retarding any further. Net-net, all the additional advance I put in at idle is gone by 5 psi and from that point on everything is at stock timing settings.

For marking the timing degrees on the crank pully, I just measured the outer circumference, divided by 360, and if my brain remembers it ended up being 1mm space between each 1.0 degree mark. I didn't have a fancy MSD degree wheel so did it the old fashioned way and marked the pully with a permanent marker for 25 degrees either side of TDC.

I welcome any and all knowledge on whether we can shave off the extra timing more gradually than I have done, such as David has suggested .3-.5* for each 1.0psi. I am far from a pro on this topic, learning as I go along, with minimal tools(can you say Dyno?) to check progress along the way.

My installation is pretty packed in there, not near as clean and nice as Dave's. I'll hobble down to the shop and take a picture of it after a couple more Vicodan. I just broke my damn foot yesterday whilst doing an extended wheel stand on my ancient 360MX, so mastering the stairs with a pair of crutches takes some doing. And, the bad part is that it was my clutch foot...so I've got plenty of time to consider all sorts of options but no way to test them out until next spring.

Thanks for the info guys.
I'm not completely done with all of the MSD installation and some other things yet. I'll take some pics when it's done.

I've reorganized and taped up the extremely confusing wiring mess I had in the motor compartment last week and have to redo some of my extra AC fan wiring still.
I don't know if it works yet. If it doesn't I'll just wire the front fuel pump relays ground wires directly to the igniton switch rather than pull the rear wiring harness apart again.

Some kind of backup wiring for the fuel pumps has to go in too.
The overly complicated origonal fuel pump wiring with one fuse and 2 red relays in front and one nightmare yellow relay and overboost sensor in the back controlling the grounding of the front 2 relays have a mind of their own and just can't be trusted after 20+ years... not in my car anyway.

I have the MSD 6AL mounted horizontal on the firewall in the engine compartment on the passenger side next to the top shock mount. Put it there because I'd have to remove the entire CIS unit or remove the engine just to get an electirc drill back there to drill holes to mount it over on the driver side of the firewall.
I put an MSD high vibration blaster coil where the origonal one was.

Then the MSD 8762 boost retard box is mounted vertically with the controls facing the back of the car on the rear console where the origonal CDI was. It fits well there and I can get at the lockable retard threshold adjustment easily.
The amount of boost retard per lb of boost adjustment knob is going on the top of the plastic auto heat box in between the seats.
There's no where on the dash or center console I could stand seeing that silly looking thing so between the seats on the equally goofy looking autoheat box where it is still easy to reach while driving works for me.

and when is it going to cool off here in south florida?

Ben,
Just catching up on this thread.

How much retard does the map sensor give?
Do you know what timing advance the motor is seeing at full boost and high rpm?
Best,
John

Helmsy,

Thanks for the info. It allows us to confirm whether we have the correct Dist.
or not. The R & L do in fact refer to Right turning or left turning Distributors. I know what your talking about with the German I have a 12 page Bosch document that breaks down all the numbers on all these distributors but it's in German. Dumb American here.

Cole

Mister Mark,

I knew there was something wrong when we didn't hear from you.

OLD FARTS ARE NOT SUPPOSED TO DO WHEELSTANDS ANYMORE !!!!!

I learned that last year and I have shoes older than you.


Cole

But I've been doing wheel stands since I was a kid (that's my excuse and I'm sticking to it). Still a kid at heart, a stupid one I guess. Dirt bikes have a way of biting you once in awhile...it just goes with the territory, living on the edge, doing what you love to do. Unfortunatley the human body's recuprative powers seriously wane as we age.

You and I will have to hook up a bit later when I'm back on my feet (literally).

Good info! Still, I'm scratching my head. I may be 4* more advanced than your example, or may not be. Read on and feel free to shoot holes.

What you've described is basically where I'm set at, BUT I set my inital idle timing (8*BTDC) with the vacuum line connected...assuming that as soon as the throttle plate opens I instantly gain 10* of advance (because the 10* idle vaccum retard goes away). Thus I would essentially be at 18 degrees BTDC as soon as the go pedal is pressed past idle. Then add 18 degrees of mechanical advance and I would be at 36* by 1700 rpms and beyond. And with my dual can dizzy, I would get 10* boost retard (or so others have claimed...I really should confirm though), therefore ending up with 26 BTDC on full boost....which would cause quick meltdown if not for the fact that I shaved off all 8 degrees by .3 bar....thus leaving 18 degrees advance at full boost. My 7006 is pretty much at full boost by 3800 rpms.

Enough trying to describe in writing. I started plotting this out on an excel spreadsheet the other day. Will have to finish it and post.

Mark,

My experience with dirt bikes was much the same, going over a jump in the mud and my right foot pushed off the foot peg when I landed it instantly folded under the foot peg and disloged my foot from the the rest of my leg at the ankle . Reallllly ugley.

I think your fine with what you have done, it is basicly the same, you either dial it all in at idle or you add it to the vacuum retard. I'm just going by what JW suggested which was just disconnect the vac advance/ retard and set all your inital timing with the light, 6 of one & 1/2 dozen of the other.

I think we have established some reasonable paramaters for timing a street turbo from what we have learned here. We know we want more advance up front to get it going and we know it "doesn't need" nor like a excessive advance at full boost. I do think we will find we don't need to take a lot of timing out on iniial boost but take it out faster after .4 or .5. I also think final advance on boost is going to be slightly above 22* or so.

I'm waiting to get MAP/RPM feed back from the Lm-1 so we can look at what we see in the way of a manifold pressure curve, and we will get a feel for when boost starts and when it is all in. At that point we will know where and when we really need to tune the timing. I've got a GM 3bar. MAP sensor I'm tying into the LM-1.

But what I do know is, spending our time here hashing this out will keep us off dirt bikes.

Cole

The LM-1 map will help immensely, vs. shooting in the dark. I appreciate your efforts.

Been thinking of building a monster snowmobile...you know, tripple expansion chambers, ported, all the good go-fast stuff. See if I can't hit a buried tree stump to keep things interesting this winter. :D

My 6AL was installed by the PO in the old CDI location. Not much room left on that side of the engine for the retard module, so what I did was to piggy-back it and connect to the lower portion of the 6AL by drilling and tapping two holes in the 6AL (between the cooling fins) and mounting the retarded thing in that fashion, so it sits below the 6AL and doesn't interfere with air flow. The adjusting knob I mounted just south-west of everything....out of the way, very hard to adjust without a mirror to see the dial, but then I don't intend to be adjusting it every day. See the crappy pictures (hard to get a good shot with the IC in the way.
Way better would be on the firewall, but pulling the engine just to drill a couple holes is better left for the next time I do a valve adjustment with the engine out.

http://forums.pelicanparts.com/uploa...1256655228.jpg
http://forums.pelicanparts.com/uploa...1256655250.jpg

Mark,

Crafty little b------ aren't ya. Nice work, nice color on the car too. Obviously a man of exquisite taste.

I have a new 6.0 aluminum head small block in you looking for something to push a snow mobile.

Cole