Building "Thor"
Discussion
Storer said:
Hopefully a few answers to the above questions/comments.
The original twin Zenith carbs like to 'slosh' great dollops of fuel into the engine. They are mated to a water cooled manifold and the whole arrangement makes accessing the 'between V' spark plugs (it has 24 spark plugs) a bugger. This carb/manifold arrangement also weighs about 75lbs!!!
It makes the engine running and starting more 'hit and miss' too.
I could have gone for three 102mm throttle bodies mounted to a common inlet manifold but that would still cause access issues.
The BMW M3 E46 bodies are 50mm individual units on a common shaft. With a new shaft of stainless steel they can be spaced as needed. I will have to fabricate a fuel rail to suit, but will probably not need the balance pipe as there will be air movement in the head between cylinders as this will not be completely sealed.
The control of the throttles is mechanical and the banks can be linked to a single throttle cable. They already have a position sensor that can feed the ECU. It is likely that the existing injectors will be large enough but time will tell. They are plentiful and well known in the tuning market.
With electronic control of the spark and injection the engine will be much more tractable and fuel consumption improved. I want to use this car a lot when it is complete so would like to get the best MPG I can but still have the 'fun' of a vast engine.
A purist would say 'leave it as it is' but then the same could be said about the whole car. Besides, if it doesn't work I have another complete engine I could fit instead!
Paul
Flames from the exhaust may have to be fake though!!!
I'm thinking Megasquirt?The original twin Zenith carbs like to 'slosh' great dollops of fuel into the engine. They are mated to a water cooled manifold and the whole arrangement makes accessing the 'between V' spark plugs (it has 24 spark plugs) a bugger. This carb/manifold arrangement also weighs about 75lbs!!!
It makes the engine running and starting more 'hit and miss' too.
I could have gone for three 102mm throttle bodies mounted to a common inlet manifold but that would still cause access issues.
The BMW M3 E46 bodies are 50mm individual units on a common shaft. With a new shaft of stainless steel they can be spaced as needed. I will have to fabricate a fuel rail to suit, but will probably not need the balance pipe as there will be air movement in the head between cylinders as this will not be completely sealed.
The control of the throttles is mechanical and the banks can be linked to a single throttle cable. They already have a position sensor that can feed the ECU. It is likely that the existing injectors will be large enough but time will tell. They are plentiful and well known in the tuning market.
With electronic control of the spark and injection the engine will be much more tractable and fuel consumption improved. I want to use this car a lot when it is complete so would like to get the best MPG I can but still have the 'fun' of a vast engine.
A purist would say 'leave it as it is' but then the same could be said about the whole car. Besides, if it doesn't work I have another complete engine I could fit instead!
Paul
Flames from the exhaust may have to be fake though!!!
Didn't realise they were 50mm each! That's a fair old bit of flow. Did you say that they will not be true ITBs but on common manifolds beneath the throttle bodies? If they are joined , by how many cylinders?
Also what was the reason for the water cooled manifold? Was it more of a water heated manifold?
Also what was the reason for the water cooled manifold? Was it more of a water heated manifold?
I personally wouldn't be fitting individual throttle bodies to this engine!
When you have a 26l engine, throttle progression is important, and that you get from a nice big plenum and a "smaller" (relative) throttle plate area.
I'd get a pair of massive throttles (truck, Viper, etc) and fab a large volume plenum (>60litres would be nice!). Using a MAP sensor on the plenum will provide accurate load determination, and will be fine for extra performance (accurate spark control will likely net you several hundred Nm on an engine of this capacity)
When you have a 26l engine, throttle progression is important, and that you get from a nice big plenum and a "smaller" (relative) throttle plate area.
I'd get a pair of massive throttles (truck, Viper, etc) and fab a large volume plenum (>60litres would be nice!). Using a MAP sensor on the plenum will provide accurate load determination, and will be fine for extra performance (accurate spark control will likely net you several hundred Nm on an engine of this capacity)
Max_Torque said:
I personally wouldn't be fitting individual throttle bodies to this engine!
When you have a 26l engine, throttle progression is important, and that you get from a nice big plenum and a "smaller" (relative) throttle plate area.
I'd get a pair of massive throttles (truck, Viper, etc) and fab a large volume plenum (>60litres would be nice!). Using a MAP sensor on the plenum will provide accurate load determination, and will be fine for extra performance (accurate spark control will likely net you several hundred Nm on an engine of this capacity)
Way to technical for me and I don't need more torque. 1500ftlbs is already an issue for the Phantom III running gear.When you have a 26l engine, throttle progression is important, and that you get from a nice big plenum and a "smaller" (relative) throttle plate area.
I'd get a pair of massive throttles (truck, Viper, etc) and fab a large volume plenum (>60litres would be nice!). Using a MAP sensor on the plenum will provide accurate load determination, and will be fine for extra performance (accurate spark control will likely net you several hundred Nm on an engine of this capacity)
Please also remember that maximum RPM will be 2700 to 2800 and max torque at about 1200. We are talking about an engine with very different charicateristics to a modern engine.
I do not need to maximise power or torque. I think just over 100mph in a 1937 Rolls Royce chassis with drum brakes and crude dampers/springs/steering is plenty fast enough. The original V12 7.5 litre engine was about 20% of the power I will have and the weight of the finished car will be similar to the limousine.
Comments are always welcome but please remember the reasoning I am using in this build.
Paul
Clive posted a link to this on his 962 build thread, but having just spent the last 2+ hours watching it, I thought I would add it here for anybody that hasn't seen it.
I suspect it isn't his first build!
http://www.badobsessionmotorsport.co.uk/test/index...
Great work though.
Enjoy
Paul
I suspect it isn't his first build!
http://www.badobsessionmotorsport.co.uk/test/index...
Great work though.
Enjoy
Paul
Storer said:
Max_Torque said:
I personally wouldn't be fitting individual throttle bodies to this engine!
When you have a 26l engine, throttle progression is important, and that you get from a nice big plenum and a "smaller" (relative) throttle plate area.
I'd get a pair of massive throttles (truck, Viper, etc) and fab a large volume plenum (>60litres would be nice!). Using a MAP sensor on the plenum will provide accurate load determination, and will be fine for extra performance (accurate spark control will likely net you several hundred Nm on an engine of this capacity)
Way to technical for me and I don't need more torque. 1500ftlbs is already an issue for the Phantom III running gear.When you have a 26l engine, throttle progression is important, and that you get from a nice big plenum and a "smaller" (relative) throttle plate area.
I'd get a pair of massive throttles (truck, Viper, etc) and fab a large volume plenum (>60litres would be nice!). Using a MAP sensor on the plenum will provide accurate load determination, and will be fine for extra performance (accurate spark control will likely net you several hundred Nm on an engine of this capacity)
Please also remember that maximum RPM will be 2700 to 2800 and max torque at about 1200. We are talking about an engine with very different charicateristics to a modern engine.
I do not need to maximise power or torque. I think just over 100mph in a 1937 Rolls Royce chassis with drum brakes and crude dampers/springs/steering is plenty fast enough. The original V12 7.5 litre engine was about 20% of the power I will have and the weight of the finished car will be similar to the limousine.
Comments are always welcome but please remember the reasoning I am using in this build.
Paul
That's why you want one or two normal but large throttle bodies on a large normal plenum.
It gives you a perfect load signal using a std MAP sensor, it reduces the amount of "Linkages" etc that you have to arrange to work and adjust perfectly, and it means the relatively small "size" of the throttle plates will give you a nice gentle off idle torque progression. Precisely what is needed in your application. I'm sure a couple of Dodge Viper or LS engine throttle bodies will be perfect. Either gut the electronics and convert to a cable (easily done) or better still, get your EMS to run the std electronic throttle bodies as is, which also gets you idle speed control etc.
ivanhoew said:
and give easy access to the inner plugs max?
Can't be beyond the wit of man to make the plenum removable, or what about two plenums, one per bank etc. I bet that will be less effort than trying to get all 12 individual throttle plates balanced so it will drive nicely!And, why do you need immediate access to the spark plugs? With EFi, a decent calibration, and some decent plugs, they should be fit and forget ;-)
all true , but missing the real point.
GERT big multiple BELLMOUTHS echoing their snorkely thunder, to scare anything living with a radius of approx. 5.7 miles (unless overcast, which will increase range ).
you either love this sort of thing ,and will make sacrifices for it... or you don't . ;-)
GERT big multiple BELLMOUTHS echoing their snorkely thunder, to scare anything living with a radius of approx. 5.7 miles (unless overcast, which will increase range ).
you either love this sort of thing ,and will make sacrifices for it... or you don't . ;-)
Clive's 962 is here
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
He is speeding this build along nicely.
Paul
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
He is speeding this build along nicely.
Paul
These M3 throttle bodies are very simple. The actuator shaft is mounted in bearings on the bodies and each butterfly is connected to the shaft with a ball and socket rod.
Each has an adjustable stop on the butterfly and it's own spring return.
The two shafts will be linked together again with a ball and socket shaft. All very simple and mechanical (none of the mystical electronic wizardry!) and all controlled by a simple throttle cable from the loud pedal.
Paul
Each has an adjustable stop on the butterfly and it's own spring return.
The two shafts will be linked together again with a ball and socket shaft. All very simple and mechanical (none of the mystical electronic wizardry!) and all controlled by a simple throttle cable from the loud pedal.
Paul
After reading through this I had to post this short film from 4oD.....
http://www.channel4.com/programmes/guy-martins-pas...
http://www.channel4.com/programmes/guy-martins-pas...
Max_Torque said:
That's why you want one or two normal but large throttle bodies on a large normal plenum.
This is going back a bit, but I think Charlie originally had a throttle at each end of a single plenum (Omega 2.5 v6 items IRRC): 
Are you in touch with Charlie?
Edited by eliot on Saturday 23 August 09:12
Edited by eliot on Saturday 23 August 09:13
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