different engine in an mx5 mk 2
Discussion
Hello to you all!
For my first involvement in a discussion on pistonheads i would like to pose the question, (Has anyone ever put a good diesel engine into an mx5 ? This is because i absolutely love my car but with the coming raise in fuel prices and v.a.t. increase i wonder if it would be possible to fit a more economical engine but with similar performance. For example i had in mind something like a vrs engine or mondeo turbo diesel.
Or please tell me if i am being a complete PLONKER and should be driving a fiat panda.
(I actually love fiat panda,s much to the annoyance of my teenage sons.)
Look forward to any answer. TA.
For my first involvement in a discussion on pistonheads i would like to pose the question, (Has anyone ever put a good diesel engine into an mx5 ? This is because i absolutely love my car but with the coming raise in fuel prices and v.a.t. increase i wonder if it would be possible to fit a more economical engine but with similar performance. For example i had in mind something like a vrs engine or mondeo turbo diesel.
Or please tell me if i am being a complete PLONKER and should be driving a fiat panda.
(I actually love fiat panda,s much to the annoyance of my teenage sons.)
Look forward to any answer. TA.
It's been discussed before and I agree that the right diesel engine i.e. one that actually revs a bit and has a broad spread of torque could work quite well. However, diesel engines tend to be pretty heavy so it could screw the handling. Maybe something like the Ford 1.6 TD would be better.
However... I think a small turbo petrol would be a better match, have better economy, would be lighter so further improving the handling and sound & feel better. With something like the new Mini Cooper engine I doubt there would be much difference between that and a diesel.
Of course none of that really matters as it would be a pointless exercise. The money it would cost to do the conversion would probably take 200k miles to pay for itself. You'd be better off doing an LPG conversion.
However... I think a small turbo petrol would be a better match, have better economy, would be lighter so further improving the handling and sound & feel better. With something like the new Mini Cooper engine I doubt there would be much difference between that and a diesel.
Of course none of that really matters as it would be a pointless exercise. The money it would cost to do the conversion would probably take 200k miles to pay for itself. You'd be better off doing an LPG conversion.
I honestly dont believe that economical and performance belong in the same sentence (when you mean powerful by performance).
You could find a more efficient motor out there that has more bang for your liter, but its not gonna show a worthwhile decrease... A high flow cat will likely show you the biggest increase in fuel economy without sacrificing performance. Note that I did not say removing the cat, the cat is required to keep compression up in the cylinders, and aids in a sort of EGR effect. Another mod that might help is a new intake (dependant on your setup). Honestly i havent screwed with my mx5 (mines a stock turbo model also) much since i bought it, so i dont know what kind of numbers you can expect or even that these are worthwhile mods, but they have worked well on my previous cars (that i made these mods too).
What I would do, look into hypermiling. Its driving techniques to get better fuel economy out of your car. Use your common sense tho, some of the guys who do this are a little extreme.
You could find a more efficient motor out there that has more bang for your liter, but its not gonna show a worthwhile decrease... A high flow cat will likely show you the biggest increase in fuel economy without sacrificing performance. Note that I did not say removing the cat, the cat is required to keep compression up in the cylinders, and aids in a sort of EGR effect. Another mod that might help is a new intake (dependant on your setup). Honestly i havent screwed with my mx5 (mines a stock turbo model also) much since i bought it, so i dont know what kind of numbers you can expect or even that these are worthwhile mods, but they have worked well on my previous cars (that i made these mods too).
What I would do, look into hypermiling. Its driving techniques to get better fuel economy out of your car. Use your common sense tho, some of the guys who do this are a little extreme.
dblack1 said:
I honestly dont believe that economical and performance belong in the same sentence (when you mean powerful by performance).
You could find a more efficient motor out there that has more bang for your liter, but its not gonna show a worthwhile decrease... A high flow cat will likely show you the biggest increase in fuel economy without sacrificing performance. Note that I did not say removing the cat, the cat is required to keep compression up in the cylinders, and aids in a sort of EGR effect. Another mod that might help is a new intake (dependant on your setup). Honestly i havent screwed with my mx5 (mines a stock turbo model also) much since i bought it, so i dont know what kind of numbers you can expect or even that these are worthwhile mods, but they have worked well on my previous cars (that i made these mods too).
What I would do, look into hypermiling. Its driving techniques to get better fuel economy out of your car. Use your common sense tho, some of the guys who do this are a little extreme.
What? I'm afraid I've got to disagree with pretty much everything you've written.You could find a more efficient motor out there that has more bang for your liter, but its not gonna show a worthwhile decrease... A high flow cat will likely show you the biggest increase in fuel economy without sacrificing performance. Note that I did not say removing the cat, the cat is required to keep compression up in the cylinders, and aids in a sort of EGR effect. Another mod that might help is a new intake (dependant on your setup). Honestly i havent screwed with my mx5 (mines a stock turbo model also) much since i bought it, so i dont know what kind of numbers you can expect or even that these are worthwhile mods, but they have worked well on my previous cars (that i made these mods too).
What I would do, look into hypermiling. Its driving techniques to get better fuel economy out of your car. Use your common sense tho, some of the guys who do this are a little extreme.
You'd free up some economy IF the stock cat was blocked - but you'll not change it even removing the cat completely (I did this - my economy was unchanged. My other car - ironically American, also runs fine without cat)
As for economy and performance, well you need to see some of the European diesels over here. 50mpg + and 130mph+ performance are all in reach with more mid range driveability than the equivalent petrol. The only disadvantages that remain are increased engine weight and an increase in purchase cost. Also - with 5.7 litre Corvette's being quite capable of high 20'3 and even 30 mpg on the cruise then you can nowadays have your cake and eat it.
EGR is there to reduce peak combustion temperatures on part load and reduce NOx emissions, it doesn't contribute to economy.
I've also tried hypermiling techniques (including engine off-coast-start etc.) in the '5 - and I can safely say best I got it to was 32mpg - normal very careful driving would see 29-30mpg, normal 37 mpg and oddly, trying to wipe the tread off the tyres still gets 27mpg. In truth - these cars are probably most hobbled by the gearing.
Anyway, I'm still interersted in the normal annual mileage the OP is trying to cover. You have to do quite a few miles to a) justify a conversion or even b) justify running a second diesel car, no matter how cheap.
Remember every extra car - £200 on road tax (assume older car) + £250 insurance (if you're lucky) + £50 if it sails its MOT + repairs + tyres + servicing. I'll ignore the unquantified ones but that is an extra £500 a year which equates to 2400 miles of driving in the MX5 at today's prices, that's before you've done any miles in the diesel.
kevin senft said:
Hello to you all!
For my first involvement in a discussion on pistonheads i would like to pose the question, (Has anyone ever put a good diesel engine into an mx5 ? This is because i absolutely love my car but with the coming raise in fuel prices and v.a.t. increase i wonder if it would be possible to fit a more economical engine but with similar performance. For example i had in mind something like a vrs engine or mondeo turbo diesel.
Or please tell me if i am being a complete PLONKER and should be driving a fiat panda.
(I actually love fiat panda,s much to the annoyance of my teenage sons.)
Look forward to any answer. TA.
Why don't you just LPG it??? That way you will have your similar performance and it will be cheaper to run than a deisel For my first involvement in a discussion on pistonheads i would like to pose the question, (Has anyone ever put a good diesel engine into an mx5 ? This is because i absolutely love my car but with the coming raise in fuel prices and v.a.t. increase i wonder if it would be possible to fit a more economical engine but with similar performance. For example i had in mind something like a vrs engine or mondeo turbo diesel.
Or please tell me if i am being a complete PLONKER and should be driving a fiat panda.
(I actually love fiat panda,s much to the annoyance of my teenage sons.)
Look forward to any answer. TA.
LPG conversion would probabley be about the same price as a engine swap and a lot less hassle franv8 said:
I've also tried hypermiling techniques (including engine off-coast-start etc.) in the '5 - and I can safely say best I got it to was 32mpg - normal very careful driving would see 29-30mpg, normal 37 mpg and oddly, trying to wipe the tread off the tyres still gets 27mpg. In truth - these cars are probably most hobbled by the gearing.
I believe part of the issue is the basic way the early ECU's operate by simply chucking fuel at the engine when you accelerate resulting in no different in MPG whatever you seem to be doing. I've heard of people getting improvements in MPG, 40MPG on a run etc., when using a mappable ECU with a standard car.Unfortunatly not a cheap option though, most are the best part of a grand, and then there's the fitting and mapping. Mine set me back £2k all in.
You save 4.6p per mile - (assuming going 30-40 mpg...£500 to do the job), so 10667 miles.
MPG increase is likely to be optimistic. But if you're doing the average 12k a year and are keeping the car, maybe it stacks up?
It's a shame you can't reap the benefits of lower tax that higher mpg brings to post 2000 vehicles.
MPG increase is likely to be optimistic. But if you're doing the average 12k a year and are keeping the car, maybe it stacks up?
It's a shame you can't reap the benefits of lower tax that higher mpg brings to post 2000 vehicles.
Got to second Lazza's comments; are you comfortable fitting one yourself as they're not just a plug and play piece of kit? If not, add a couple of hundred pounds at least for fitting. Can you map one yourself? Without a rolling road and wideband sensors you can only let the ECU selftune, assuming it's capable; mine will self tune, but only for maximum performance not economy and it's not comparable to a professional setup. Add £300 for a custom map on a rolling road.
You also will need to factor in an increase in insurance premiums as your car is now classed as modified. At 4.6p/mi I'd estimate half your savings being consumed by higher insurance premiums, which are guaranteed, against economy savings, which are not.
I'd still place money on a 2nd hand diesel workhorse being more financially economical when all your indirect costs are factored in.
You also will need to factor in an increase in insurance premiums as your car is now classed as modified. At 4.6p/mi I'd estimate half your savings being consumed by higher insurance premiums, which are guaranteed, against economy savings, which are not.
I'd still place money on a 2nd hand diesel workhorse being more financially economical when all your indirect costs are factored in.
To use an ecu upgrade to fine-tune the fuelling you will also need a wide-band O2 sensor so that's another couple of hundred quid to factor in. Also, if you want to ensure reliability, unless you are a real car electric wizard, it would be a good idea to buy a plug-n-play harness adapter which is another hundred quid or so.
I had factored the wideband in. And the Megasquirt PnP - which plugs straight onto the connector that the Mazda ECU was plugged into.
So yes, the rest assumes you can use a soldering iron, are happy to put the labour in yourself etc. etc. - and I have no idea if it would achieve 40mpg, although something is clearly lacking in the economy side design of the MX5, when Yank V8's can equal beat it with 3.5 times the capacity. I am assuming that tuning can be done without the services of a rolling road too.
If we did the same questions for the diesel motor - well, either it's find all the bits secondhand/in a scrappy/donor car, make up/have made several bespoke parts made up.
And maybe it is cheaper to buy a diesel banger - but I remember there was a time in my life I wanted to have my fun all of the time. You won't get a top notch diesel that combines performance and economy for a few hundred quid...
(If you dare to mention some banged up tuned Peugeot or something, remember the comments re: insurance)
On insurance, I wonder what the real difference would be for an aftermarket ECU, last time I ran a significantly altered car they were interested in % more horsepower - if it's there for economy it may not attract much of a premium, depending on insurer.
So yes, the rest assumes you can use a soldering iron, are happy to put the labour in yourself etc. etc. - and I have no idea if it would achieve 40mpg, although something is clearly lacking in the economy side design of the MX5, when Yank V8's can equal beat it with 3.5 times the capacity. I am assuming that tuning can be done without the services of a rolling road too.
If we did the same questions for the diesel motor - well, either it's find all the bits secondhand/in a scrappy/donor car, make up/have made several bespoke parts made up.
And maybe it is cheaper to buy a diesel banger - but I remember there was a time in my life I wanted to have my fun all of the time. You won't get a top notch diesel that combines performance and economy for a few hundred quid...
(If you dare to mention some banged up tuned Peugeot or something, remember the comments re: insurance)
On insurance, I wonder what the real difference would be for an aftermarket ECU, last time I ran a significantly altered car they were interested in % more horsepower - if it's there for economy it may not attract much of a premium, depending on insurer.
franv8 said:
although something is clearly lacking in the economy side design of the MX5, when Yank V8's can equal beat it with 3.5 times the capacity.
There is a bit more to it than that though... On a big yank V8 you can use less of the performance to keep pace with a more wrung-out '5 and hence keep the throttle loading lower and hence better economy. Not to mention the stratospheric gearing most yank V8s will pull in comparison to a '5.
Even my 6-speed Mk2.5 pulls around 3.1k at 70mph (off the top of my head) and a big V8 is likely to pull a bit more than half of that.
If the MX5 is in perfect condition and if it's a Mk1 1.6 the AFM is adjusted correctly then they barely over fuel at all. They really aren't as bad as people make out. The earlier Mk1 1.6 has a pretty basic ecu so there will be gains to be had there but it's not going to be a +25% improvement in economy as suggested. I'd be surprised if it gets better than a +5% improvement over a well serviced and well tuned standard car.
It is a funny old game, economy and what makes it work/not work.
(Sorry OP - this is well off topic to what you were originally asking)
Lazza - I'd be tempted to agree with you - although what should a 1.6 in good condition really do? There are so many people quoting the high-20's fuel consumption and only the odd one more.
There are cases of larger engines being more economical than some of the smaller engined cars - but normally that's in the same range and only the case if they're quite heavy.
(Most Yanks, and diesels too, seem to pull 2k rpm at 70 by the way. Modern Vette's/Mustangs may pull even less)
BUT - if you take some really small engined cars, they can get boggling economy too.
In the case of the MX5 -
+ Light weight
+ smallish frontal area
+ Small engine
+ Electronic Fuel injected
+ 16 valve
+ Distributourless ignition
- Low gearing
- Poor aerodynamics
- what else? Poor engine management? Cams set up for revving/speed and not cruise?
I can't help but think there could be a more small 1.6 car-like economy in there somewhere. When I met my wife, she had one of the old shape Megane Coupe's - similar engine spec, we used to amuse ourselves at being able to get 42 mpg out of the thing, admittedly it was a decade younger.
(Sorry OP - this is well off topic to what you were originally asking)
Lazza - I'd be tempted to agree with you - although what should a 1.6 in good condition really do? There are so many people quoting the high-20's fuel consumption and only the odd one more.
There are cases of larger engines being more economical than some of the smaller engined cars - but normally that's in the same range and only the case if they're quite heavy.
(Most Yanks, and diesels too, seem to pull 2k rpm at 70 by the way. Modern Vette's/Mustangs may pull even less)
BUT - if you take some really small engined cars, they can get boggling economy too.
In the case of the MX5 -
+ Light weight
+ smallish frontal area
+ Small engine
+ Electronic Fuel injected
+ 16 valve
+ Distributourless ignition
- Low gearing
- Poor aerodynamics
- what else? Poor engine management? Cams set up for revving/speed and not cruise?
I can't help but think there could be a more small 1.6 car-like economy in there somewhere. When I met my wife, she had one of the old shape Megane Coupe's - similar engine spec, we used to amuse ourselves at being able to get 42 mpg out of the thing, admittedly it was a decade younger.
My Focus 1.8 Zetec does 34mpg. Day in, day out, normal trips to/from work which is all b-roads or long motorway trips. However, when driving it I very rarely use more than 3k rpm. The engine is tuned so that it doesnt need to be revved to make it go. I can make it go faster by revving it harder, in fact if I push it to 5.5k it can feel pretty good but it feels best when changing much earlier than that. Driving an na MX5 I rarely change gear below 3k rpm. It can be driven below 3k rpm but it feels much better at higher revs even if you aren't pushing on. The Focus is a family hatch and the MX5 is a sportscar. They shouldn't and don't drive the same.
When I had an na Mk1 1.8 I usually got around 28mpg. If I drove carefully on my normal routes I could push that to about 32mpg and once when driving home from Scotlandi tried to drive from above Edinburgh to Wokingham on a single tankful by driving very carefully and nearly made it, had to fill up in High Wycombe which I think was closer to 40mpg. I've never got that sort of economy from the Focus!
So basically what I'm saying is, it's not so much the economy of the car as the style of car and how that affects how it's driven.
When I had an na Mk1 1.8 I usually got around 28mpg. If I drove carefully on my normal routes I could push that to about 32mpg and once when driving home from Scotlandi tried to drive from above Edinburgh to Wokingham on a single tankful by driving very carefully and nearly made it, had to fill up in High Wycombe which I think was closer to 40mpg. I've never got that sort of economy from the Focus!
So basically what I'm saying is, it's not so much the economy of the car as the style of car and how that affects how it's driven.
Is a great idea, when a mk4 golf pr passat tdi 130 chipped to approx 180bhp with & tons of torque- 280lbs/ft I think it was, gives an av 50mpg & mid 40s even when ragged & 55 on a long steady run, over 100k miles hauling 1400 odd kg of vw about.
So in a 1000kg mx5 that would be a really decnet amount of grunt & great mpg & if you drive in europe rather than uk then diesel is so much cheaper too.
I'd happily have one for road & track frollics, would give the performance of a pretty tasty turbo'd mx5 anyway & murder lesser regular budget turbo/supercharger set ups.
Anything is posible- but the trouble is its not going to be cheap or easy to do, the older pre pd vw 1.9 tdis would be easier & cheaper & have less electronics & still good but its still not 5 mins work to do.
So in a 1000kg mx5 that would be a really decnet amount of grunt & great mpg & if you drive in europe rather than uk then diesel is so much cheaper too.
I'd happily have one for road & track frollics, would give the performance of a pretty tasty turbo'd mx5 anyway & murder lesser regular budget turbo/supercharger set ups.
Anything is posible- but the trouble is its not going to be cheap or easy to do, the older pre pd vw 1.9 tdis would be easier & cheaper & have less electronics & still good but its still not 5 mins work to do.
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