RE: 180hp and 52mpg from Skyactiv-X Mazda 3
Discussion
DanielSan said:
HorneyMX5 said:
DanielSan said:
2 litre and 180bhp... Dear Mazda, please put that donkey in the MX5, Kthanxbye
They already do. https://www.pistonheads.com/news/driven/mazda-mx-5...
caelite said:
I wonder if they knock like a diesel. Would love to see the PH reaction as the the saviour technology of the N/A engine come clattering along like an old van. :P
"diesel knocking" is simply an artifact of the fast burn, and that fast burn is why the engine burns fuel more efficiently! In a theoretically perfect engine, the burn would not start until top dead centre (minimum chamber volume), and it would burn the entire charge instantly, creating heat, which creates pressure, that would instantly push the piston all the way down. In that way, all the heat from the burning fuel would go directly into useful work in the piston. BUT, the burn is not instant, far from it, and all engines have to start their charge burning as the piston is still on the way up, that longer duration, and the fact the chamber surface area is, on average, larger than it's minimum possible surface area means some heat is inevitably lost. That heat of course, ends up in the metal components of the engine and has to be removed by the engines cooling system. That cooling system recovers none of that energy, it is just dumped straight overboard by the radiator!
As a result the more "efficient" and engine is, the more "knocky" it will sound. Modern direct injection, fast burn gasoline engines sound "diesely" precisely because they are fast burning......
edeath said:
caelite said:
I wonder if they knock like a diesel. Would love to see the PH reaction as the the saviour technology of the N/A engine come clattering along like an old van. :P
Isn't this engine supercharged? The figures are still impressive - but its not the saviour of NA some people are saying.
havoc said:
Max_Torque said:
havoc said:
Some of us don't like the low-rev torque focus that a lot of the turbo-petrols are now afflicted with, so while a free-revving petrol of any kind is to be applauded, a n/a one is especially welcome.
But i know that the vast majority of non-enthusiast drivers, the sort of people who buy Mazda SUVs are going to feel that this new engine is "flat as a fart" and will never rev it hard enough to find the (reasonably decent but not that special) power at the top end.It makes 225 Nm, a typical 2.0tdi is making 400 Nm these days. So in any given gear, that's half the performance.........
(e.g. my 'torque-less' Type R has (+/- a few %) exactly the same wheel-torque as a same-era 320d, and a flatter torque-curve to boot...)
You can bet you ass that to get sub 100gm/km that engine did not exceed 1800rpm at any point in the drive cycle, so if you want max economy, you need tall gearing, therefore a low flywheel torque means low "In-gear" performance. An fairly unsporting SUV is not really the sort of car you'll want to row along by using all the gears all the time! (with 180 bhp, the absolute performance will be ok of course, but owners just won't ever use that performance)
Max_Torque said:
er, you can't ignore gearing because these days "downspeeding" is as important as anything else in terms of minimising losses!
Some figures I saw a while ago suggested that being able to pull 6th instead of 5th at a given road speed typically resulted in a 5% improvement in fuel economy.
Max_Torque said:
So in any given gear, that's half the performance.........
Aaannd then the diesel has to change up, losing a ton of acceleration. The petrol keeps going for another 2000rpm with acceleration continuously increasing. Diesel and petrol are very different definitions of performance.Grrbang said:
Aaannd then the diesel has to change up, losing a ton of acceleration. The petrol keeps going for another 2000rpm with acceleration continuously increasing. Diesel and petrol are very different definitions of performance.
er ,no, because you are conveniently forgetting that the final drive on a lower reving car is commensurately higher! For example, a E90 BMW 335i (revs to 7k) has 6 gears and does 155mph, and a 335d (revs to 4.5k) has, 6 gears and does 155mph.
The 335i is juust faster than the 335 because it makes about 30 bhp more, in the real world, from a rolling start, (ie in-gear) the less powerful 335d has no problem keepig up because it has significantly more torque at a lower rpm, so although it's PEAK power might be less, the area under the curve, is actually nigh on identical for the two cars......
Will be interesting to try one, its a respectable output in a small hatch but as has been mentioned a lot of folk are now used to having a lot of low down torque these days due to so many cars being turbocharged, previously only owners of Rover V8 engined cars or similar had the joy of 240 lb/ft at not many rpm but now, any turbo diesel or petrol typically has 200 lb/ft or more, low in the romp range, 165 lb/ft is pretty good for an NA engine but it comes in at 4k plus.
Hopefully people give it a chance, nice to see some more innovation in Petrol engines.
Hopefully people give it a chance, nice to see some more innovation in Petrol engines.
On the road, the Swift Sport with 118lb ft and peak power at 6,900rpm never felt too slow. So I don't feel a linear, relatively torquey petrol will, either. I have a 2.0 turbo. It feels like it's pulling very hard and yet the road speed never feels like it has got there any quicker than the Swift would have, apart from a standing start.
Master Bean said:
edeath said:
caelite said:
I wonder if they knock like a diesel. Would love to see the PH reaction as the the saviour technology of the N/A engine come clattering along like an old van. :P
Isn't this engine supercharged? The figures are still impressive - but its not the saviour of NA some people are saying.Max_Torque said:
er, you can't ignore gearing because these days "downspeeding" is as important as anything else in terms of minimising losses!
You can bet you ass that to get sub 100gm/km that engine did not exceed 1800rpm at any point in the drive cycle, so if you want max economy, you need tall gearing, therefore a low flywheel torque means low "In-gear" performance. An fairly unsporting SUV is not really the sort of car you'll want to row along by using all the gears all the time! (with 180 bhp, the absolute performance will be ok of course, but owners just won't ever use that performance)
Who's talking about SUVs? I'm talking about cars in general...and last time I looked this was for driving enthusiasts, not people-carrier enthusiasts...You can bet you ass that to get sub 100gm/km that engine did not exceed 1800rpm at any point in the drive cycle, so if you want max economy, you need tall gearing, therefore a low flywheel torque means low "In-gear" performance. An fairly unsporting SUV is not really the sort of car you'll want to row along by using all the gears all the time! (with 180 bhp, the absolute performance will be ok of course, but owners just won't ever use that performance)
As for 'not exceeding 1800rpm', that's still not relevant because the petrol engine, with a higher rev limit, will still have shorter gearing than the diesel...
dukebox9reg said:
I get over 50mpg out of my Leon FR Sport 190 petrol which has a much more user friendly 236lbft and 7 spd DSG.
Just this morning on my commute I got 51.8mpg.
26 miles of backroads, M40/M42 and a bit of town. Average 42mph.
I'm guessing the Mazda with that little torque etc making half decent progress and 50mpg would be very hard.
Seat doesn't quote higher than 41mpg on wltp test for the 190 (will be same test conditions as Mazda) so imagine you would get a stack more out of the Mazda driven same way on your commute.Just this morning on my commute I got 51.8mpg.
26 miles of backroads, M40/M42 and a bit of town. Average 42mph.
I'm guessing the Mazda with that little torque etc making half decent progress and 50mpg would be very hard.
I too can get 50mpg on my commute in my nine year old Abarth Punto which has more power and doesn't have a 7th gear to assist but on the test cycle it would also be low 40s.
The point of the wltp test cycle is so you can do such comparisons between cars under the same conditions and know one car is more or less economical than another.
Mazda sounds great.
Edited by sandys on Thursday 6th June 22:26
I think this is quite interesting, I'd like to give one a try. I'm not a diesel fan and I've always preferred NA engines so it's great to see effort being put into developing them. Couple this with Mazdas efforts at making their cars light and they have a recipe that appeals more than pretty much any other manufacturer.
I went from a Mazda 6 2.0 petrol to an Insignia because I was doing a lot of motorway miles and a n/a engine with a modest torque curve wasn't cutting it. However, I do miss my Mazda in many ways and think this new 3 could be a great car for anyone not doing the majority of their miles on motorways where the lack of a turbo becomes an issue. There's a lot to be said for a responsive n/a petrol, free from annoying turbo lag and with a lighter front end than your typical diesel. Also, with less to go wrong, reliability should be good. Mazda petrol engined cars are normally pretty bullet proof. All good.
Mazda do know how to make a good drivers car, so I am looking forward to trying this. Im sure its real world MPG will be very good. The current MX5 delivers very strong real world MPG, far in excess of turbo charged rivals.
Mazda do know how to make a good drivers car, so I am looking forward to trying this. Im sure its real world MPG will be very good. The current MX5 delivers very strong real world MPG, far in excess of turbo charged rivals.
Edited by greenarrow on Friday 7th June 11:25
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