912c
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Re: 912c
That will be fun but I think they are quite expensive? I can't remember the price but ...
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Re: 912c
neilbardsley wrote: ↑Tue Apr 18, 2023 10:40 am That will be fun but I think they are quite expensive? I can't remember the price but ...
https://www.carmagazine.co.uk/car-revie ... kamm-912c/
How much does a customer-spec Kamm 912c cost?
Customer cars cost £280,000 including a donor 912. The condition of that car is a variable in the price – if needs a lot of work doing it might be more, if it’s in great shape it might be less.
The power to weight ratio is close to that of the second-gen Porsche 996 GT3, because the 912c is such a light vehicle. With fluids, it weighs 750kg, and its dry weight is not much more than 700kg.
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Re: 912c
Agreed a £300 CDI system would be a good addition to that
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Re: 912c
It runs a 123 ignition distributor with a custom curve for the cam/porting/engine. Doesn’t need a CDI ignition. If you have ever got a shock from a 123 distributor you would understand why!neilbardsley wrote: ↑Tue Apr 18, 2023 4:42 pm Agreed a £300 CDI system would be a good addition to that
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The JPS kit is a bit of a work of art. Very well designed and manufactured and expensive, but there its a small market and development costs have to be factored in.
To get 170 BHP out of a 616 reliably needs a lot of thought and development.but the engine is a peach
1966 912
1969 912/6 hotish rod in build
1974 914 Dead
LI 125 Lambretta (Yeah right it’s a 125)
Mini Cooper s
1969 912/6 hotish rod in build
1974 914 Dead
LI 125 Lambretta (Yeah right it’s a 125)
Mini Cooper s
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Re: 912c
I've driven it! Lots of fun although it was very twitchy as it had been setup for track when I had a steer on bumpy local lanes.
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Re: 912c
But the 123 doesn't create the shock? That is the coil surely? The distributor is just a switch?SeanP wrote:It runs a 123 ignition distributor with a custom curve for the cam/porting/engine. Doesn’t need a CDI ignition. If you have ever got a shock from a 123 distributor you would understand why!neilbardsley wrote: ↑Tue Apr 18, 2023 4:42 pm Agreed a £300 CDI system would be a good addition to that
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The JPS kit is a bit of a work of art. Very well designed and manufactured and expensive, but there its a small market and development costs have to be factored in.
To get 170 BHP out of a 616 reliably needs a lot of thought and development.but the engine is a peach
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“A REMINDER. I would be grateful if those members who have borrowed bits from me in emergencies (e.g starter motor, oil cooler, etc) would return them and/or contact me”. – Chris Turner RIP
Re: 912c
The coil plays a part and a standard distributor is a switch but a 123 distributor is an electronic switch without the resistance or condenser passing the spike down to ground so all of the charge goes to the coil without losing any potential energy. You see the 123 distributors are quite clever things not only do they have the correct curves programmed in them which does not meander around the curve like the mechanical distributors, they also pass all of the electrical power with minimal losses. So it’s like an enhanced signal to the coil to produce the spark.neilbardsley wrote: ↑Wed Apr 19, 2023 9:22 amBut the 123 doesn't create the shock? That is the coil surely? The distributor is just a switch?SeanP wrote:It runs a 123 ignition distributor with a custom curve for the cam/porting/engine. Doesn’t need a CDI ignition. If you have ever got a shock from a 123 distributor you would understand why!neilbardsley wrote: ↑Tue Apr 18, 2023 4:42 pm Agreed a £300 CDI system would be a good addition to that
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The JPS kit is a bit of a work of art. Very well designed and manufactured and expensive, but there its a small market and development costs have to be factored in.
To get 170 BHP out of a 616 reliably needs a lot of thought and development.but the engine is a peach
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They are a great replacement for worn mechanical distributors as everyone knows but they also have added benefits.
The 123 distributor is one of the best upgrades I have done to my 912 to date. I have not had to touch it since I installed it and set the timing. The cap is still like new along with the rotor arm. It’s a constant good quality spark with no spiking or arcing. I only replaced the spark plugs last year because I thought I should. The plugs I took out were still working perfectly and looked like new after 5 years of service.
Hence there is no need for a CDI on the engine with the compression ratio.
People are running 911 engines on a 123 ignition system on standard Kettering ignition systems without the plug fouling issues.
1966 912
1969 912/6 hotish rod in build
1974 914 Dead
LI 125 Lambretta (Yeah right it’s a 125)
Mini Cooper s
1969 912/6 hotish rod in build
1974 914 Dead
LI 125 Lambretta (Yeah right it’s a 125)
Mini Cooper s
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- Nurse, I think I need some assistance
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Re: 912c
Sorry to back on about the 123 (which is a great product). The problem, I thought, with higher compression 616 engines is that the piston has to be domed and therefore divides the camber in two. Hence for the 4 cam and race 911 engines Porsche went to twin spark. I'm not sure the 123 helps with this problem. However, having a CDI would mean a bigger voltage and bigger spark which might help with higher compression engines?
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“A REMINDER. I would be grateful if those members who have borrowed bits from me in emergencies (e.g starter motor, oil cooler, etc) would return them and/or contact me”. – Chris Turner RIP
Re: 912c
Neil, I’m not an expert on this but if the piston is domed how does that split the combustion chamber in two, surely it just makes the combustion chamber ring shaped?
Sean made a point about the 123 using all of the electricity produced (I’m assuming he means both the low and high tension circuits end up being sent to the plugs) in which case there will be a slightly bigger spark at the plugs.
CDI (bigger voltage/bigger spark) is surely achieving the same end result?
Twin spark would have two plugs per combustion chamber which would obviously help with a combustion chamber made of two halves if indeed that is the case.
Sean made a point about the 123 using all of the electricity produced (I’m assuming he means both the low and high tension circuits end up being sent to the plugs) in which case there will be a slightly bigger spark at the plugs.
CDI (bigger voltage/bigger spark) is surely achieving the same end result?
Twin spark would have two plugs per combustion chamber which would obviously help with a combustion chamber made of two halves if indeed that is the case.
Burgundy 69 912
Audi A4 1.8T sport avant
VW T25 magnum multivan
Audi A4 1.8T sport avant
VW T25 magnum multivan
Re: 912c
Neil
Have you read up about John Willhoits development of his engine conversions? It’s an interesting read of all the avenues he went down, twin plugs, CDI, fuel injection. It answers a lot of questions.
What JPS have done is developed an engine package and backed up their designs and products with testing and verification of the results. The very same thing that willhoit has done.
CDI isn’t the be all and end all of all of ignition systems. It’s actually pretty old technology these days with coil on plug systems, crank fire and ecu’s.
These people selling the wares are standing by their products. And if it needed a CDI then they would have surely installed one.
Oh and the arc directly out of a 123 distributor is a pretty lively spark that can jump a bit. That’s why they say not to connect the black wire Shen setting it up and keep it away fro metal things
Have you read up about John Willhoits development of his engine conversions? It’s an interesting read of all the avenues he went down, twin plugs, CDI, fuel injection. It answers a lot of questions.
What JPS have done is developed an engine package and backed up their designs and products with testing and verification of the results. The very same thing that willhoit has done.
CDI isn’t the be all and end all of all of ignition systems. It’s actually pretty old technology these days with coil on plug systems, crank fire and ecu’s.
These people selling the wares are standing by their products. And if it needed a CDI then they would have surely installed one.
Oh and the arc directly out of a 123 distributor is a pretty lively spark that can jump a bit. That’s why they say not to connect the black wire Shen setting it up and keep it away fro metal things
1966 912
1969 912/6 hotish rod in build
1974 914 Dead
LI 125 Lambretta (Yeah right it’s a 125)
Mini Cooper s
1969 912/6 hotish rod in build
1974 914 Dead
LI 125 Lambretta (Yeah right it’s a 125)
Mini Cooper s
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- Nurse, I think I need some assistance
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Re: 912c
Good point I forgot that Wilhoit has redesigned the heads too. In particular so the chamber is smaller so a higher compression ratio can be achieved with a flatter piston making twin spark/cdi less needed. That said I had a 123 on my 912 and it made a difference v the 009 but the 6v CDI on my 356 was a bigger step.
I too like what JPS is doing but I think a set of his heads is about what I paid for my 912!
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I too like what JPS is doing but I think a set of his heads is about what I paid for my 912!
Sent from my M2004J19C using Tapatalk
“A REMINDER. I would be grateful if those members who have borrowed bits from me in emergencies (e.g starter motor, oil cooler, etc) would return them and/or contact me”. – Chris Turner RIP