Daimler 250 V8 engine mods
Discussion
RW774 said:
You have forgotten the ECU.So how do you map it Jith? who`s going to give you access to the software? Bosch? .Nope .
Also how do you gain access to the ECU . They are all pre set by the factory.
Non starter I`m afraid
Oh my goodness! What have I started? Now I'm not going down this K-Jet route but what about boring the Daimler to 3.0 litres then fitting twin Mk1 Golf Gti systems? Just musing!Also how do you gain access to the ECU . They are all pre set by the factory.
Non starter I`m afraid
On the topic of k-Jetronic, just trying to blow some cobwebs out of my mind but: Wasn' the k-Jet a totally mechanical system without an ECU? I remember struggling with the D-Jetronic on my old 350 SLC then a similar systems on the early V12 Jags which did have ecu's but I thought the Golf Gti and similar Wolfsburg products with K-Jet were just mechanical. Probably wrong! My memory is going. Anyone fancy a pint?
Bit too heavy for the Mk2 is the old 4.5.Plus Diamler only made 800 4.5s V8s.Definetly the lighter V8 is the way forward.
Just squirting in the juice will be no benefit at all over your carbs, it still has to be metered, it still needs adjustment and will still need tuning.I don`t think either of the systems mentioned will be of any great benefit over a closed loop mappable management system. The technolgy is available in the public domain so why not make the most of it.
Love the Hilborn setup.
Just squirting in the juice will be no benefit at all over your carbs, it still has to be metered, it still needs adjustment and will still need tuning.I don`t think either of the systems mentioned will be of any great benefit over a closed loop mappable management system. The technolgy is available in the public domain so why not make the most of it.
Love the Hilborn setup.
RW774 said:
You have forgotten the ECU.So how do you map it Jith? who`s going to give you access to the software? Bosch? .Nope .
Also how do you gain access to the ECU . They are all pre set by the factory.
Non starter I`m afraid
K-Jet is a mechanical system RW. It is exclusively the only fuel injection system, with the exception of a pressurised, diesel pump type, that will run with no electronics. As long as you have power to the fuel pump, it will get you home.Also how do you gain access to the ECU . They are all pre set by the factory.
Non starter I`m afraid
That is the very reason why, on an older vehicle, it is most definitely a starter.
My 500 Merc has KE Jet, and has outstanding performance and fuel economy. I can achieve over 30 MPG with damn nearly 300 BHP; and it's 23 years old!!
The original system is run only by a small control relay and this controls the switching functions and the idle speed: in other words it is not part of the mixture control. The tuning of the system is effected by two means. The first is the shape and diameter of the cone chamber that houses the main butterfly; there are dozens of variations on these, all available second hand. The second is the position of the butterfly fulcrum in relation to the internal fuel shuttle, and this is almost infinitely adjustable with an allen key.
If I were carrying out the mods to the Daimler 250 engine I would base it on a 350 Merc system from the late '70s. You can pick up a whole car just now for three or four hundred quid!
The only time you would need an ECU is if you went for the last KE-Jet system with a lambda. But this can be set up with a standard code reader, so it's not a problem.
My point about reliability can best be made from BMW experience in the '70s. BMW used L-Jet, a fully electronic system on all their injected cars with the exception of the 323i. For some inexplicable reason they chose to mount the airflow meter on top of the exhaust manifold resting on a rubber bobbin on the cylinder head. The result was constant premature failure due to transmitted heat and engine vibration. I replaced dozens of these things. When the airflow meter fails on this system, the car stops dead; end of story.
The 323i however was an absolutely stonking car to drive, with tremendous throttle response and absolute reliability. I have no memory of any breakdown on these cars with the exception of the fuel pump on high mileage vehicles.
The only reason that K-Jet never saw its way on to British cars, was because of the stupid bloody minded mentality in British Leyland of sticking to ludicrously outdated forms of British fuelling systems such as SU carbs. Jaguar were still fitting SUs and non electronic distributors to the 3.4 XJ in 1986!!
The Daimler engine on K-Jet would be superb; and cheap to do into the bargain.
Jith, morning to you ,hope you are well, thanks for the info. I had forgotten about these old systems.The KE for sure needed the ECU, but surely each system was designed purely for the application, not multi application. I mean you cannot run the old Granada system on an Audi or vice versa without metering adjustments. I didn`t think it possible to run the system on another applcation without a full overhaul of the metering unit, so as the jetting can suit the vehicle use,that would then make it not cost effective. But I`m all ears...............you never stop learning in this game.
RW774 said:
Top man, don`t overcook the haggis
Was late getting back last night coz I couldn't catch the haggis. The wee s
te was too quick for me. 
This is a link to an excellent site I use. You can download the Bosch technical manual for K-Jet from here. It has some very good engine theory as well as injection information. You have to subscribe first, but it's free and well worth the effort.
http://www.scribd.com/doc/3299223/Bosch-KJetronic-...
Important points are as follows - On Page 17 the concept of air shrouded injection valves is explained. I first saw this on the '81 Audi 100s, a brand new model at the time with a previously undreamt of low Cd figure. The combination of this figure and K-Jet enabled these cars to achieve over 50 MPG! This is 1981 remember!
Pages 18-24 discuss the principles of the air-flow sensor, and like all good ideas it is an amazingly simple but brilliantly clever principle. Page 24 is the relevant one when considering modification. The shape of the cone funnel is what determines the mode of fuel delivery, and it is shaped to utilise the best fuelling for three different engine conditions.
1. Maximum load or power.
2. Part load or light throttle, i.e. cruising.
3. Idle speed.
By modifying these three in combination you can achieve anything you want for your engine.
On an older vehicle the best system I would use would be the 2nd generation, which has no lambda or auxiliary air valve but uses a rotary idle valve and fuel shut off on the overrun. You would also probably find that you do not need a cold start valve either if you set up the system properly.
On the 2.5 Daimler unit I would use the basic system from a 350 Merc with a cone and injectors from a 260E W124 or an Audi 100 2.3 5 cylinder and start from there.
There are a few very good books on tuning these systems that you can get from Amazon, and you can refine the tuning from those. Once you get it right it will run for ever.
You should get at least a 30% improvement on fuel consumption over the SU carbs.
Edited by jith on Thursday 17th September 09:06
Jith thanks for that, very ,very interesting.I had never before given any thought to the old systems and there availablity/ tune ability.If it is possibble to use the KE with a aftermarket ecu, such as the motec unit that would be about the closest to a modern system. I agree the system would probably work well, but don`t forget that the new current systems occupy far less space, have less components with the ECU doing all the work of the metering unit , fueling/ load/ start up and ignition calculations and supply without the need for the old components listed on the Bosch site. Flow rates and metering heads of the old system vary from memory , dependant on application.The installation of the old system would be very much dependant on the metering head being right first time,whereas our systems rely on the ECU programming to get the fueling right, this in conjuntion with a lambda sensor , on a rolling road with a laptop this can be achieved easily.
You will still need injector bosses welded in , but an awful lot of fabrication for the metering head. If it isn`t right forst time , you then have the grief / expense of the head being re calibrated. Then lastly, you have no control over the ignition curve.The two need to be combined to maximise your efficiency, if it cannot, it becomes a compromise.
Sorry Jith, just looking at all the pros and cons. Its definetly worth a look if you have the time to dedicate to the installation.I don`t think it commercially viable though.
You will still need injector bosses welded in , but an awful lot of fabrication for the metering head. If it isn`t right forst time , you then have the grief / expense of the head being re calibrated. Then lastly, you have no control over the ignition curve.The two need to be combined to maximise your efficiency, if it cannot, it becomes a compromise.
Sorry Jith, just looking at all the pros and cons. Its definetly worth a look if you have the time to dedicate to the installation.I don`t think it commercially viable though.
K-Jet is a nice reliable solid system.
However it is horrific in tuning terms. You would be insane to install it on an engine out of choice these days, it will cost a fortune to tune to your engine, you will lose a lot of power over alternative solutions plus you have the hassle of trying to site the injectors.
Seriously go modern with throttle bodies and ECU along the lines of megasquirt or go old school on carbs.
However it is horrific in tuning terms. You would be insane to install it on an engine out of choice these days, it will cost a fortune to tune to your engine, you will lose a lot of power over alternative solutions plus you have the hassle of trying to site the injectors.
Seriously go modern with throttle bodies and ECU along the lines of megasquirt or go old school on carbs.
wildoliver said:
K-Jet is a nice reliable solid system.
However it is horrific in tuning terms. You would be insane to install it on an engine out of choice these days, it will cost a fortune to tune to your engine, you will lose a lot of power over alternative solutions plus you have the hassle of trying to site the injectors.
Seriously go modern with throttle bodies and ECU along the lines of megasquirt or go old school on carbs.
Dear me Oliver, talk about a contradiction in terms!However it is horrific in tuning terms. You would be insane to install it on an engine out of choice these days, it will cost a fortune to tune to your engine, you will lose a lot of power over alternative solutions plus you have the hassle of trying to site the injectors.
Seriously go modern with throttle bodies and ECU along the lines of megasquirt or go old school on carbs.
Either it is good or it's not! I don't know who you are or what your experience is, but I think you're missing a vital point here. The idea is to improve on an old motor car, not turn it into some sort of retro monster. Where do you get the bits about it being horrific or costing a fortune? This is simply not true; everything is available second hand that is why I suggested it in the first place. Siting the injectors for K-Jet is exactly the same as any injection system, you are going to have to drill into the inlet tracts somewhere to install injectors, regardless of what system you use. Bear in mind the OP has engineering experience and ability.
Consider this: K-Jet was so good that Mercedes and Audi used it in closed loop form way into the '90s! If I sat you in my 500 Merc at full throttle, you would be in no doubt as to how good it is!
RW, your point about the ignition system; there is actually no reason why you cannot run K-Jet on the standard distributor. It doesn't require any ignition timing input to function. I'm not suggesting that you would do this incidentally, because the Lucas distributor in all these old cars is always the weakest link in the combustion system, but a good electronic conversion will sort that out, and with that you can set your timing at any setting you wish.
I think this would be more in keeping with the character of the car than pure electronics, not that it is actually superior in terms of out and out performance.
jith said:
wildoliver said:
K-Jet is a nice reliable solid system.
However it is horrific in tuning terms. You would be insane to install it on an engine out of choice these days, it will cost a fortune to tune to your engine, you will lose a lot of power over alternative solutions plus you have the hassle of trying to site the injectors.
Seriously go modern with throttle bodies and ECU along the lines of megasquirt or go old school on carbs.
Dear me Oliver, talk about a contradiction in terms!However it is horrific in tuning terms. You would be insane to install it on an engine out of choice these days, it will cost a fortune to tune to your engine, you will lose a lot of power over alternative solutions plus you have the hassle of trying to site the injectors.
Seriously go modern with throttle bodies and ECU along the lines of megasquirt or go old school on carbs.
Either it is good or it's not! I don't know who you are or what your experience is, but I think you're missing a vital point here. The idea is to improve on an old motor car, not turn it into some sort of retro monster. Where do you get the bits about it being horrific or costing a fortune? This is simply not true; everything is available second hand that is why I suggested it in the first place. Siting the injectors for K-Jet is exactly the same as any injection system, you are going to have to drill into the inlet tracts somewhere to install injectors, regardless of what system you use. Bear in mind the OP has engineering experience and ability.
Consider this: K-Jet was so good that Mercedes and Audi used it in closed loop form way into the '90s! If I sat you in my 500 Merc at full throttle, you would be in no doubt as to how good it is!
RW, your point about the ignition system; there is actually no reason why you cannot run K-Jet on the standard distributor. It doesn't require any ignition timing input to function. I'm not suggesting that you would do this incidentally, because the Lucas distributor in all these old cars is always the weakest link in the combustion system, but a good electronic conversion will sort that out, and with that you can set your timing at any setting you wish.
I think this would be more in keeping with the character of the car than pure electronics, not that it is actually superior in terms of out and out performance.
I would have thought my original post was self explanatory enough, however allow me to elaborate.
K-Jet was fitted to a wide range of vehicles from the 70's right through to the 90's in some cases (and with minor alterations) it is a great system in the sense that it is one step up from a carb, offers excellent reliability and is maintenance free.
However it is a rising plate metering system, while it is solid and reliable it isn't great from a performance point of view, yes I realise your Mercedes is probably quite quick, I have been in plenty of quick cars some of which even had K-Jet of variants of fitted. I just don't understand why anyone now would bother to fit K-Jet when it is out of date and fundamentally flawed not to mention no easier to fit than the 2 options I offered (carbs or modern stand alone system along megasquirt lines).
Indeed in reality K-Jet is going to be a pig to fit to the engine as not only will the OP have to find a V8 metering head (considering most made were for 4/5 pots) which will limit him to the ones fitted to Mercedes V8s mainly, he will then have to find someone to set it up and adapt it to his current engine, this will not be cheap or easy.
So to summarise if you want an out of date, performance strangling, expensive, hard to find and not easy to fit solution to your problem then K-Jet is your answer.
I actually like K-Jet, in that all my cars with it fitted will keep it fitted and I wouldn't dream of updating them, but you would be insane to take a step basckwards and fit it to a different engine out of choice.
Mornin' chaps!
Thanks again for all the various ideas and opinions on my quest to add fuel injection to my old Daimler V8. This debate seems to have sparked a lot of interest and touched a few nerves! It has unearthed some very valid ideas which I had not even thought about. So its been great to 'gas' about this topic.
At the end of the day, I am going to have to make a decision and go down one particular route.
So I am now re-asking myself "Dave, what exactly is it you're trying to achieve here!"
Well -
Firstly, I am committed to keeping my old Mk2 250 V8, no question about this. It's a good example and I have already started dressing it up with chrome wires, Coombes arches, woodrim steering wheel etc etc. I've had several 3.8 Jags over the years, loved them all and know just how far you can go with performance. So I know what this old 60's chassis is capable of. But I always like to be that little bit different - that's just me! And the Daimler is already sitting there! And I really fancy a reasonably potent V8 with a lovely sound track. (Back in the seventies in Central Africa, I had a Sunbeam Tiger with home-built straight through 'silencers' - they could here me coming for miles!)
So I want to squeeze some more performance out of the basic engine and also gain some reliability and maybe some (relative) economy. I want to do this by adding fuel injection. That much is decided.
I feel sure that by adding some modern technology in a properly engineered way, much can be achieved. I am a capable guy in both practical and technical terms but admit I haven't delved into applying fuel injection to a virgin engine project before. But if you knew what I have achieved in life, you'd understand that my current inexperience aint gonna hold me back for long.
The Daimler V8 was only dropped by Jaguar for political/rationalisation reasons at the time. So one line of thought is to try and imagine what Jaguar/Daimler might have done if they had decided to keep the engine in their lineup. Maybe K-jet would have been the way to go.
But if I'm going to do this today in 2009, I might as well go all the way. However, I want the end-product to look like it might have been production-engineered by Daimler - no cobbled-up job for me, even if it does work. I want to ditch the carbs and the original manifold, pretty as it is - I've got one sitting on my desk as we speak! But let's forget about Paxton superchargers, a stack of ram pipes sticking up through the bonnet and the like. I'm not creating a hot-rod!
I am going to investigate the possibility of increasing the capacity but suspect there could be problems including sourcing suitable pistons. If anyone has specific information on this I would be grateful to hear from you. I will do whatever I can to improve the existing heads - I feel sure there is room for gasflow improvement here plus a chance to convert to unleaded if needed.
So that leaves the induction. Right now I am favouring individual injector bodies (either bought in or made-up) topped by a custom-made manifold (or pair of cross-manifolds) plus carefully designed air-box(s) and throttle-body(s). I want an ECU I can play with and ignition system to suit.
You've given me plenty of information and ideas to chew on and I am truly grateful to you all! I've now got a lot of homework and research to do. I'll obviously be letting you know of progress in due course. (As someone famous once said 'I may be some time!')
Thanks again. Have a nice weekend!
David
Thanks again for all the various ideas and opinions on my quest to add fuel injection to my old Daimler V8. This debate seems to have sparked a lot of interest and touched a few nerves! It has unearthed some very valid ideas which I had not even thought about. So its been great to 'gas' about this topic.
At the end of the day, I am going to have to make a decision and go down one particular route.
So I am now re-asking myself "Dave, what exactly is it you're trying to achieve here!"
Well -
Firstly, I am committed to keeping my old Mk2 250 V8, no question about this. It's a good example and I have already started dressing it up with chrome wires, Coombes arches, woodrim steering wheel etc etc. I've had several 3.8 Jags over the years, loved them all and know just how far you can go with performance. So I know what this old 60's chassis is capable of. But I always like to be that little bit different - that's just me! And the Daimler is already sitting there! And I really fancy a reasonably potent V8 with a lovely sound track. (Back in the seventies in Central Africa, I had a Sunbeam Tiger with home-built straight through 'silencers' - they could here me coming for miles!)
So I want to squeeze some more performance out of the basic engine and also gain some reliability and maybe some (relative) economy. I want to do this by adding fuel injection. That much is decided.
I feel sure that by adding some modern technology in a properly engineered way, much can be achieved. I am a capable guy in both practical and technical terms but admit I haven't delved into applying fuel injection to a virgin engine project before. But if you knew what I have achieved in life, you'd understand that my current inexperience aint gonna hold me back for long.
The Daimler V8 was only dropped by Jaguar for political/rationalisation reasons at the time. So one line of thought is to try and imagine what Jaguar/Daimler might have done if they had decided to keep the engine in their lineup. Maybe K-jet would have been the way to go.
But if I'm going to do this today in 2009, I might as well go all the way. However, I want the end-product to look like it might have been production-engineered by Daimler - no cobbled-up job for me, even if it does work. I want to ditch the carbs and the original manifold, pretty as it is - I've got one sitting on my desk as we speak! But let's forget about Paxton superchargers, a stack of ram pipes sticking up through the bonnet and the like. I'm not creating a hot-rod!
I am going to investigate the possibility of increasing the capacity but suspect there could be problems including sourcing suitable pistons. If anyone has specific information on this I would be grateful to hear from you. I will do whatever I can to improve the existing heads - I feel sure there is room for gasflow improvement here plus a chance to convert to unleaded if needed.
So that leaves the induction. Right now I am favouring individual injector bodies (either bought in or made-up) topped by a custom-made manifold (or pair of cross-manifolds) plus carefully designed air-box(s) and throttle-body(s). I want an ECU I can play with and ignition system to suit.
You've given me plenty of information and ideas to chew on and I am truly grateful to you all! I've now got a lot of homework and research to do. I'll obviously be letting you know of progress in due course. (As someone famous once said 'I may be some time!')
Thanks again. Have a nice weekend!
David
As an aside to this topic how difficult would it be to replace the Borg Warner 3 speed automatic with a more modern unit with lock up overdrive top gear? Are there any obvious replacements that would be a relatively straightforward swap.
I looked at one on Friday (bit of a nail, but it got me interested) and would like to know how difficult it would be to make it a bit more suitable for modern motorway cruising.
Thanks
I looked at one on Friday (bit of a nail, but it got me interested) and would like to know how difficult it would be to make it a bit more suitable for modern motorway cruising.
Thanks
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