Die(sel) engines for kit cars?
Discussion
Just wondering what people's thoughts on sticking a diesle engine in a kit car is?
I think they could be quite good. Get a newer unit with a turbo on it and they have bags of torque and a reasonable amount of power.
I have zero idea how hard they are to tune and get running when not in a mass produced vehicle, or how heavy they generally are.
All up, I think a couple of sporty kit cars running diesel would be good for the industry, just not sure what engine I'd use, in what chassis configuration...
ETA - this was sparked by the Libra thread I briefly looked at yesterday...
I think they could be quite good. Get a newer unit with a turbo on it and they have bags of torque and a reasonable amount of power.
I have zero idea how hard they are to tune and get running when not in a mass produced vehicle, or how heavy they generally are.
All up, I think a couple of sporty kit cars running diesel would be good for the industry, just not sure what engine I'd use, in what chassis configuration...
ETA - this was sparked by the Libra thread I briefly looked at yesterday...
Edited by MTv Dave on Wednesday 13th December 10:00
The only major issue with a modern diesel is the need for a simulator/interface box for the factory ECU. As it is unlikely you will find an aftermarket ECU.
Most kit cars won't have Power Steering, Electric windows, AC, etc. Or a Body computer for that matter.
The key is simulating what the ECU is expecting.
Most kit cars won't have Power Steering, Electric windows, AC, etc. Or a Body computer for that matter.
The key is simulating what the ECU is expecting.
Diesels could open up a new niche in the kit market, maybe not for the hardcore trackday oriented guys, but the idea is very good.
You have so many modern engines, with great low end torque and good horsepower waiting to be adapted in modern kits, without forgetting fuel economy.
The choice is varied, from Ford,Vw,Audi, Bmw,Merceded, Fiat,Alfa,Peugeot and many more, just waiting to be transplanted in a lightweight sportscar.
The Vw Ecoracer sportscar concept, uses a modern Tdi engine, that will be available in your next Polo or Golf!.
There is a niche for these engines in my opinion
You have so many modern engines, with great low end torque and good horsepower waiting to be adapted in modern kits, without forgetting fuel economy.
The choice is varied, from Ford,Vw,Audi, Bmw,Merceded, Fiat,Alfa,Peugeot and many more, just waiting to be transplanted in a lightweight sportscar.
The Vw Ecoracer sportscar concept, uses a modern Tdi engine, that will be available in your next Polo or Golf!.
There is a niche for these engines in my opinion
annodomini2 said:
The only major issue with a modern diesel is the need for a simulator/interface box for the factory ECU. As it is unlikely you will find an aftermarket ECU.
Most kit cars won't have Power Steering, Electric windows, AC, etc. Or a Body computer for that matter.
The key is simulating what the ECU is expecting.
Most kit cars won't have Power Steering, Electric windows, AC, etc. Or a Body computer for that matter.
The key is simulating what the ECU is expecting.
Shouldn't be a problem I wouldn't have thought - the AC, PAS etc will have seperate control modules and taking them away shouldn't effect the ECU operation.
I think it's a great diea - and not a new one - there are several rather rapid diesel powered Quantums (for their day)
A potential concern is the weight distribution as even modern part alloy diesels tend to be quite hefty, but located in the right place that's not a disaster. The only thing that leaves is the engine response. I drive diesel's everyday and I've yet to come across one I'd really want to balance delicately on the throttle. But for a sports tourer something like a BMW 330D engine in a good lightweight RWD chasis would be awesome.
I've not had much experiance of modern diesel engine, but I know my old 306 was smooth, but not exactly responsive. The Clio dCi was better, but didn't have much poke (it was a base model so not sure what else it could do if tuned).
What are the new ones like?
Did I hear a myth that Honda are working on a V6 free rev'ving oil burner?
What are the new ones like?
Did I hear a myth that Honda are working on a V6 free rev'ving oil burner?
Chris71 said:
annodomini2 said:
The only major issue with a modern diesel is the need for a simulator/interface box for the factory ECU. As it is unlikely you will find an aftermarket ECU.
Most kit cars won't have Power Steering, Electric windows, AC, etc. Or a Body computer for that matter.
The key is simulating what the ECU is expecting.
Most kit cars won't have Power Steering, Electric windows, AC, etc. Or a Body computer for that matter.
The key is simulating what the ECU is expecting.
Shouldn't be a problem I wouldn't have thought - the AC, PAS etc will have seperate control modules and taking them away shouldn't effect the ECU operation.
I think it's a great diea - and not a new one - there are several rather rapid diesel powered Quantums (for their day)
A potential concern is the weight distribution as even modern part alloy diesels tend to be quite hefty, but located in the right place that's not a disaster. The only thing that leaves is the engine response. I drive diesel's everyday and I've yet to come across one I'd really want to balance delicately on the throttle. But for a sports tourer something like a BMW 330D engine in a good lightweight RWD chasis would be awesome.
Yes they have seperate control modules, but they all talk to each other. E.g. 99.9% of new cars have Abs, which uses wheel speed sensors. These provide vehicle speed information to the engine ECU.
If the ECU cannot see these other ECU's on the CAN bus then while it is not impossible, it may not work.
I'm only guessing here and happy to be corrected, but wouldn't you need all of the 'extra' bits on a diesel to give it a performance level similar to it's equivilent petrol engine, like turbos for instance? Therefore wouldn't it make the engine a lot bigger than the petrol one. Plus I always thought diesel engines were a lot heavier too.
annodomini2 said:
Chris71 said:
annodomini2 said:
The only major issue with a modern diesel is the need for a simulator/interface box for the factory ECU. As it is unlikely you will find an aftermarket ECU.
Most kit cars won't have Power Steering, Electric windows, AC, etc. Or a Body computer for that matter.
The key is simulating what the ECU is expecting.
Most kit cars won't have Power Steering, Electric windows, AC, etc. Or a Body computer for that matter.
The key is simulating what the ECU is expecting.
Shouldn't be a problem I wouldn't have thought - the AC, PAS etc will have seperate control modules and taking them away shouldn't effect the ECU operation.
I think it's a great diea - and not a new one - there are several rather rapid diesel powered Quantums (for their day)
A potential concern is the weight distribution as even modern part alloy diesels tend to be quite hefty, but located in the right place that's not a disaster. The only thing that leaves is the engine response. I drive diesel's everyday and I've yet to come across one I'd really want to balance delicately on the throttle. But for a sports tourer something like a BMW 330D engine in a good lightweight RWD chasis would be awesome.
Yes they have seperate control modules, but they all talk to each other. E.g. 99.9% of new cars have Abs, which uses wheel speed sensors. These provide vehicle speed information to the engine ECU.
If the ECU cannot see these other ECU's on the CAN bus then while it is not impossible, it may not work.
If you've got the right claibration in that won't be a problem at all - we've got stacks of dynos at work with light-car diesel engines on without any extraneous modules. There may be a few things that need turning off, but if you've hacked into the ECU to ramp up the fueling now you no longer need to pass an emissions ccert that wouldn't be an issue. On some of our early prototypes we use a MUX box which mimics the input from these other modules - with the possible exception of vechicle speed (from the ABS module as you say) it's hard to think which it'll need.
chris71 said:
annodomini2 said:
Chris71 said:
annodomini2 said:
The only major issue with a modern diesel is the need for a simulator/interface box for the factory ECU. As it is unlikely you will find an aftermarket ECU.
Most kit cars won't have Power Steering, Electric windows, AC, etc. Or a Body computer for that matter.
The key is simulating what the ECU is expecting.
Most kit cars won't have Power Steering, Electric windows, AC, etc. Or a Body computer for that matter.
The key is simulating what the ECU is expecting.
Shouldn't be a problem I wouldn't have thought - the AC, PAS etc will have seperate control modules and taking them away shouldn't effect the ECU operation.
I think it's a great diea - and not a new one - there are several rather rapid diesel powered Quantums (for their day)
A potential concern is the weight distribution as even modern part alloy diesels tend to be quite hefty, but located in the right place that's not a disaster. The only thing that leaves is the engine response. I drive diesel's everyday and I've yet to come across one I'd really want to balance delicately on the throttle. But for a sports tourer something like a BMW 330D engine in a good lightweight RWD chasis would be awesome.
Yes they have seperate control modules, but they all talk to each other. E.g. 99.9% of new cars have Abs, which uses wheel speed sensors. These provide vehicle speed information to the engine ECU.
If the ECU cannot see these other ECU's on the CAN bus then while it is not impossible, it may not work.
If you've got the right claibration in that won't be a problem at all - we've got stacks of dynos at work with light-car diesel engines on without any extraneous modules. There may be a few things that need turning off, but if you've hacked into the ECU to ramp up the fueling now you no longer need to pass an emissions ccert that wouldn't be an issue. On some of our early prototypes we use a MUX box which mimics the input from these other modules - with the possible exception of vechicle speed (from the ABS module as you say) it's hard to think which it'll need.
Thats what I am saying, for an off the shelf unit you would either need a simulator, or the ability to enter the ECU and modify the software so that it worked correctly.
For most garage builders of Kit cars this is not the typical approach as most do not have the skills to break into the ECU. And simulator boxes aren't cheap. Which may put them off.
Now if you could offer such a service at a reasonable cost, then people may be interested.
The only concern I personally would have is the multi-modal operation of most modern EMS units and breach of any Safety protocols fitted in the systems due to modifications made.
The advantage of building your own car is that you can make what ever you like. I would go for a pre-ECU diesel. Remember those ones with a throttle cable that went from the peddle to the pump? And probably even a non turbo version. You won't have oodles of power but they go on for ever. They are cheap, economical, readily available from the local scrappy and they are ideally suited to the back yard mechanic. It's probably where the one out of my current Escort van will finish up. And yes they are a bit heavier than the petrol equivelent, just keep that in mind when you're ordering your suspension units.
Interesting topic. I'm currently building a petrol powered kit car at the moment, but I'm planning the next one to be a diesel.
I've investigated a faire few engines for my project, and I've got the following shortlisted.
1) BMW 2.0L TD (From the X3)
2) Alfa 3.0L.
3) Jaguar 2.5L V6.
Personally I love the idea of having a really torquey track day car, running it on chip fat and giving the petrol powered cars a run for their money.
--Jools
antony moxey said:
I'm only guessing here and happy to be corrected, but wouldn't you need all of the 'extra' bits on a diesel to give it a performance level similar to it's equivilent petrol engine, like turbos for instance? Therefore wouldn't it make the engine a lot bigger than the petrol one. Plus I always thought diesel engines were a lot heavier too.
You would certainly need the turbo etc., so installation and packaging can be a little more involved than for a nat. asp. petrol engine.
Weight used to be horrendous, but modern Diesel blocks aren't as over-engineered as they once were, so the difference isn't as dramatic as you might think.
As an example, SEAT's published kerb weights for the petrol and diesel versions of the otherwise identical Ibiza Cupra are 1248 kg and 1177kg respectively so SEAT is actually saying that the diesel variant is 71 kg lighter than the petrol version!
Edited by Sam_68 on Friday 22 December 15:51
Ooooh careful! Don't ever trust a manufacturer's weight data!
I work as a weight engineer in the mainstream car industry at the moment and some of the "measures" taken to homologate vehicles are, erm, well I won't disclose them, shall we say. I want a job to go back to next year.
Basically the published weight of a car is linked to its emissions, and in some cases you might find that stating a kerb weight with a (perfectly permissible) tolerance applied in order to slot that model into a particular Inertia Test Weight Category to avoid expensive additional emissions control measures on the powertrain, is the preferred route to go.
There are other ways of reducing the published weight, which any given manufacturer may or may not have employed to match their vehicle weight to their engine emissions performance!
So far in all my work on OEM car development I haven't seen a diesel engine lighter than an equivalent-power gasoline one. I'd estimate a 30-60kg increase for an average modern turbo diesel over an equivalent N/A petrol, although it's obviously influenced by where each engine is within its development life.
Bigger the engine the bigger the delta, obviously, but a certain V6 gas and V6 diesel I'm working with at the moment are maybe 70kg apart in weight, and they're larger than those you're going to stick in a kit car.
I work as a weight engineer in the mainstream car industry at the moment and some of the "measures" taken to homologate vehicles are, erm, well I won't disclose them, shall we say. I want a job to go back to next year.
Basically the published weight of a car is linked to its emissions, and in some cases you might find that stating a kerb weight with a (perfectly permissible) tolerance applied in order to slot that model into a particular Inertia Test Weight Category to avoid expensive additional emissions control measures on the powertrain, is the preferred route to go.
There are other ways of reducing the published weight, which any given manufacturer may or may not have employed to match their vehicle weight to their engine emissions performance!
So far in all my work on OEM car development I haven't seen a diesel engine lighter than an equivalent-power gasoline one. I'd estimate a 30-60kg increase for an average modern turbo diesel over an equivalent N/A petrol, although it's obviously influenced by where each engine is within its development life.
Bigger the engine the bigger the delta, obviously, but a certain V6 gas and V6 diesel I'm working with at the moment are maybe 70kg apart in weight, and they're larger than those you're going to stick in a kit car.
FNG said:
Ooooh careful! Don't ever trust a manufacturer's weight data!
Yes, looking at the data for the other petrol and diesel Ibiza models, they do seem a bit random... for example, while the Ibiza Cupra diesel is supposedly lighter than the petrol version, the diesel FR (next model down) is supposedly 80kg heavier than the petrol FR!
Never the less, for the sort of engine sizes that would make sense in a lightweight kit-car, it would appear that weight differences between diesel and petrol are now manageable, if the overall design takes account of them?
Difference between a BEC and an equivalent CEC is more than between a petrol and a diesel. Apart from packaging (turbos and intercoolers where chassis members are) an extra xx kg on the front end is manageable. OK it won't give any improvements in handling but these things are surmountable - springs and tyre pressures would sort out such a small increase.
(Not that many manufacturers have different spring sets for BECs let alone re-rated dampers.)
I think realistically you wouldn't make any changes from the petrol setup unless it was hitting the bumstops.
I like the idea of a seriously torquey power delivery and veg-oil-ness for a roadgoing kit, but I'd personally want something revvy and screaming if any track use was on the cards.
(Not that many manufacturers have different spring sets for BECs let alone re-rated dampers.)
I think realistically you wouldn't make any changes from the petrol setup unless it was hitting the bumstops.
I like the idea of a seriously torquey power delivery and veg-oil-ness for a roadgoing kit, but I'd personally want something revvy and screaming if any track use was on the cards.
FNG said:
I like the idea of a seriously torquey power delivery and veg-oil-ness for a roadgoing kit, but I'd personally want something revvy and screaming if any track use was on the cards.
I know where you are coming from......
My current project has a straight 6 BMW engine, which sounds like a banshee in a liquidizer :-)
But I'd be happy to trade that in if I knew the engine was bullet proof, and I could do a day on the track for half the cost.
I'm pretty sure my next build will be a diesel, my only real headache will be to try and make it sounds like an audi R10 :-)
--Jools
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