911-3.0 Project - Triggers and sensors questions

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ManuFromParis
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Re: 911-3.0 Project - Triggers and sensors questions

Postby ManuFromParis » Fri Dec 08, 2017 2:11 am

Peter M wrote:Hi Manu,
I'm interested in your installation as I've been thinking of a similar conversion for my 3.2.

Just a couple of questions:

Are you using a Clewett crank sensor and sensor mount? I was under the impression that the sensor mount does not stop you from keeping the distributor and you simply had to slide the sensor down the mount to maintain the correct clearance to the wheel?
----- See above

Have you seen the Rasant distributor conversion kit? http://rasantproducts.com/porsche-911-d ... apter-kit/
----- I have but I was planing to modify the distributor to add a custom rotor and a small hall effect sensor. Will keep you posted about that

Did you consider using the Clewett cam position sensor but would prefer not to remove the engine to install?
----- This setup is on a 3.0 so I'd have to modify the cam and cover

Surely the 60-2 crank position wheel will provide better resolution than the 30-2 alternative and should be used?

Did you think about using modern design 4 hole injectors that atomise better than the old style single hole injectors?
----- Problem is that with this 3.0 setup, the injector position is driven by the 3.2 intake pipes and it would not allow to have 4 streams as the might hit sides before entering the pipe itself. So for this 3.0 setup, I choose single stream parts.
But you're right, my next 3.2 setup may use 4 streams, if they are long enough


One last comment. The original Motronic ECU may have separate connections for the injectors but it actually batch fires them all together so they are not semi sequential at all.
----- The 3.2 Motronic is a "semi sequential"
Each injector wire splits in two to handle 2 opposite injectors.
Same for sparks.


Look forward to seeing some photos of your completed conversion.
----- Will come as soon as I start the fitting
:D


Regards
Peter

Peter M
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Re: 911-3.0 Project - Triggers and sensors questions

Postby Peter M » Fri Dec 08, 2017 12:47 pm

Excellent!

I'm pleased you are still working on the conversion and haven't let lapse.

Just a few clarifications to our previous posts:


Did you consider using the Clewett cam position sensor but would prefer not to remove the engine to install?
----- This setup is on a 3.0 so I'd have to modify the cam and cover


My understanding of the Clewett cam position sensor is that you remove the welsh plug at rear of cam housing, tap one of the holes in the end of the camshaft, insert bolt into newly threaded hole to act as trigger and then bolt on a new cover that holds the sensor and replaces the previously used welsh plug.

Did you think about using modern design 4 hole injectors that atomise better than the old style single hole injectors?
----- Problem is that with this 3.0 setup, the injector position is driven by the 3.2 intake pipes and it would not allow to have 4 streams as the might hit sides before entering the pipe itself. So for this 3.0 setup, I choose single stream parts.
But you're right, my next 3.2 setup may use 4 streams, if they are long enough



Assuming you are using the standard 3.2 fuel rails with the standard 3.2 intake manifold there are plenty on more modern style injectors that fit. I'm currently using Bosch 0280 155 931 as direct replacements as they have the older style electrical connections so no need to change anything.

One last comment. The original Motronic ECU may have separate connections for the injectors but it actually batch fires them all together so they are not semi sequential at all.
----- The 3.2 Motronic is a "semi sequential"
Each injector wire splits in two to handle 2 opposite injectors.
Same for sparks.


Manu, they are batch fired every revolution. Lorenfb from Rennlist repairs Motronic as a business and has confirmed this is wired into the circuit board. https://rennlist.com/forums/911-forum/9 ... st13709916

With the ignition, it is full sequential because of the use of a conventional distributor.

Keep at it as I'm keen to see your results!

Regards
Peter

Peter M
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Re: 911-3.0 Project - Triggers and sensors questions

Postby Peter M » Fri Dec 08, 2017 12:53 pm

So I went for a 3.2 flywheel that fits the 3.0SC engines. A Custom Crank Sensor bracket shall be made though, depending on chosen Hall Effect Sensor part.

@Matthew :
Actually, I was just about to ask you about this :
I was planning to have the 3.2 flywheel machined to suppress 3 teeth off the 129 (then balanced), but I was wondering if this setup could be entered : 129 - 3

Why 3 ? because 129 can be divided by 3 and the gap would be larger.

But now I'm a bit frightened by your last answers... Does that mean I shall need a software update ?


Manu,
You can't mill off 3 teeth from a 3.2 flywheel as the teeth actually belong to the ring gear and would likely render the starter inoperative!

A 60-2 wheel on the pulley is looking like the only solution.....

Peter M
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Re: 911-3.0 Project - Triggers and sensors questions

Postby Peter M » Fri Dec 08, 2017 2:44 pm

You may find this thread interesting:
https://rennlist.com/forums/911-forum/6 ... eeded.html

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HaltechMatthew
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Re: 911-3.0 Project - Triggers and sensors questions

Postby HaltechMatthew » Fri Dec 08, 2017 2:53 pm

I already asked R&D to confirm the operation of a 129 tooth crank trigger. This is exceptionally rare to be asked and nobody can remember anyone who has ever used it. For them to confirm it they need time to program the signal generator, test all outputs for correct functionality, etc.. and quite simply the engineers are so solidly booked I cant get it done in a timely fashion. By the time I have an answer you could have already trial tested it.

There is no reason for it not to work. Just I dont have the ability to give you an answer at our end for certain.

Same goes for cutting teeth. Absolutely no idea how it would react but the software says this should work.

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ManuFromParis
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Re: 911-3.0 Project - Triggers and sensors questions

Postby ManuFromParis » Fri Dec 08, 2017 5:59 pm

Peter M wrote:You can't mill off 3 teeth from a 3.2 flywheel as the teeth actually belong to the ring gear and would likely render the starter inoperative!


It's funny because I thought the same in the beginning, and everyone I tell about this idea has the same reaction, including the machine shop who looked at me as if I were the latest dumbest, but we all simply forgot that the starter ring goes on the pressure plate !
;-)

This flywheel ring teeth is fully dedicated to the sensors, and when comparing with the SC flywheel, you can see the "extension" from the regular historic 911 flywheel.
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ManuFromParis
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Re: 911-3.0 Project - Triggers and sensors questions

Postby ManuFromParis » Fri Dec 08, 2017 6:17 pm

Peter M wrote:My understanding of the Clewett cam position sensor is that you remove the welsh plug at rear of cam housing, tap one of the holes in the end of the camshaft, insert bolt into newly threaded hole to act as trigger and then bolt on a new cover that holds the sensor and replaces the previously used welsh plug.
----- Ok, now I remember seing this system. I might go this route then.
That one ?
http://www.clewett.com/index.php?main_p ... cts_id=169


Assuming you are using the standard 3.2 fuel rails with the standard 3.2 intake manifold there are plenty on more modern style injectors that fit. I'm currently using Bosch 0280 155 931 as direct replacements as they have the older style electrical connections so no need to change anything.
----- The fitting I made of the injectors showed that the injector end remains in the pipe hole and is not coming through, especially since the heat gasket is very thick and has a dent making this little tunnel even longer. So I assumed it was a better idea to remain with a straight single gas output.

Manu, they are batch fired every revolution. Lorenfb from Rennlist repairs Motronic as a business and has confirmed this is wired into the circuit board.
----- Yes plugs sparked at every revolution, meaning it's a "lost spark" system. But since the distributor has this 6-in-1 trigger output and the flywheel has the TDC little insert I wonder why it can't be a proper full-ignition system. Anyway, the Elite 750 will be, with the help of the two sensors I'm planning and a custom Injector loom of course.

With the ignition, it is full sequential because of the use of a conventional distributor.
----- As there are only 3 wires coming out of the motronic and they divide by two to drive each injector (main connector to the injector loom has 4 wires only), it means the gas flow has to be split in two for each cylinder, on every revolution, as in a semi-sequential system. I think I'm right on this one.

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ManuFromParis
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Re: 911-3.0 Project - Triggers and sensors questions

Postby ManuFromParis » Fri Dec 08, 2017 6:19 pm

HaltechMatthew wrote:I already asked R&D to confirm the operation of a 129 tooth crank trigger. This is exceptionally rare to be asked and nobody can remember anyone who has ever used it. For them to confirm it they need time to program the signal generator, test all outputs for correct functionality, etc.. and quite simply the engineers are so solidly booked I cant get it done in a timely fashion. By the time I have an answer you could have already trial tested it.

There is no reason for it not to work. Just I dont have the ability to give you an answer at our end for certain.

Same goes for cutting teeth. Absolutely no idea how it would react but the software says this should work.


Ok Matt, let's cross fingers then...
:P :?

Peter M
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Re: 911-3.0 Project - Triggers and sensors questions

Postby Peter M » Sat Dec 09, 2017 8:35 pm

Manu,
Couple of comments:
My understanding of the Clewett cam position sensor - http://www.clewett.com/index.php?main_p ... cts_id=169

Yep! That's the one!


The fitting I made of the injectors showed that the injector end remains in the pipe hole and is not coming through, especially since the heat gasket is very thick and has a dent making this little tunnel even longer. So I assumed it was a better idea to remain with a straight single gas output.


Do you plan to open up the existing SC inlet ports to match the 3.2 intake manifold? When you do this it will solve the obstruction of the injector spray path.


Yes plugs sparked at every revolution, meaning it's a "lost spark" system. But since the distributor has this 6-in-1 trigger output and the flywheel has the TDC little insert I wonder why it can't be a proper full-ignition system.

Actually, one plug is sparked every 120 degrees of crank revolution as the distributor rotor moves 60 degrees between each cylinder. There is no lost spark in the standard Porsche setup. However I know that many people when they dispose of the distributor and use a lost spark arrangement to simplify installation.


As there are only 3 wires coming out of the motronic and they divide by two to drive each injector (main connector to the injector loom has 4 wires only), it means the gas flow has to be split in two for each cylinder, on every revolution, as in a semi-sequential system. I think I'm right on this one.

I know I'm right! :-)
If you check the injector driver pins (14 & 15) on the Motronic ecu with a continuity tester you'll find they are connected.

Cheers
Peter

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ManuFromParis
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Re: 911-3.0 Project - Triggers and sensors questions

Postby ManuFromParis » Sat Dec 09, 2017 9:16 pm

Again, with 1 wire for 2 injectors, how can the one concerned be fired and not the other ?

Peter M
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Re: 911-3.0 Project - Triggers and sensors questions

Postby Peter M » Sat Dec 09, 2017 10:24 pm

Manu,
I'm saying all 6 injectors are fired simultaneously every crank revolution!

Peter M
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Joined: Wed Dec 06, 2017 7:11 am

Re: 911-3.0 Project - Triggers and sensors questions

Postby Peter M » Fri Dec 29, 2017 3:05 pm

Peter M wrote:[i]

Manu,
You can't mill off 3 teeth from a 3.2 flywheel as the teeth actually belong to the ring gear and would likely render the starter inoperative!
.....


I apologise Manu, you can mill off teeth as the ring gear is separate to the engine sensor teeth. A good photo here of a G50 equipped 3.2.

http://forums.pelicanparts.com/uploads10/IMG_0741sm1182665558.jpg


Carry on!


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