Peculiar engine sizes... Where are they now?
Discussion
I was behind an old Nissan Micra today with a 1.3l petrol engine, and I remembered seeing an old Audi A6 with a 2.6 l badge on the back at the weekend.
Led me to think, what lead manufacturers to specify a particular capacity for their engine designs? Especially those "strange" sizes, like the zetec 1.25, various diesel 1.7's, 2.1 V6s etc.
Today you just seem to get standard even numbers- 1.0, 1.2, 1.4,1.6, 2.0, 3.0 etc. legislation must surely play a part, but what drove GM to use a turbocharged 2.8l for Saab Aeros and Vectra/Insignia VXRs? Why not 3.0?
Is there any engineering theory behind this? Why don't we see many "odd" engines sizes any more? (Alfa 1750TB is really a 1.8, can't think of any others in production. )
Genuinely intrigued. Any engine designers out there with a view?
Led me to think, what lead manufacturers to specify a particular capacity for their engine designs? Especially those "strange" sizes, like the zetec 1.25, various diesel 1.7's, 2.1 V6s etc.
Today you just seem to get standard even numbers- 1.0, 1.2, 1.4,1.6, 2.0, 3.0 etc. legislation must surely play a part, but what drove GM to use a turbocharged 2.8l for Saab Aeros and Vectra/Insignia VXRs? Why not 3.0?
Is there any engineering theory behind this? Why don't we see many "odd" engines sizes any more? (Alfa 1750TB is really a 1.8, can't think of any others in production. )
Genuinely intrigued. Any engine designers out there with a view?
Ignoring the pure engineering reasoning behind particular engine sizes, you don't often see manufacturers badging their cars by engine size anymore, BMW / MB are probably the most prolific and quite a few of their badges don't line upto the engine size, 335 etc being a prime example.
As for the true engine size there a whole myriad of reasons why you don't make the engine to the nearest round number, that is tail wagging the dog, so to speak, depending on what the engine is going to power and its variants / expandability will dictate its cc.
As for the true engine size there a whole myriad of reasons why you don't make the engine to the nearest round number, that is tail wagging the dog, so to speak, depending on what the engine is going to power and its variants / expandability will dictate its cc.
A lot of the reasoning can be due to fiscal regulations in different countries - I know that Mercedes developed some 2.8L engines because it dropped their cars into lower tax bands in many countries than the 3.0L engines they already had .
Sometimes , odd displacements occur because a six cylinder engine may be basically a four with two extra cylinders added on . Eg if someone had a 1.6L four , they could make a 2.4L six by adding two more cylinders . Mercedes at one point had a 2 litre 4 cyl , 2.5 litre 5 cyl and 3 litre six - all basically the same engine with differing numbers of cylinders .
Lastly - 'boring or stroking' an existing engine to improve performance can result in strange displacements !
Sometimes , odd displacements occur because a six cylinder engine may be basically a four with two extra cylinders added on . Eg if someone had a 1.6L four , they could make a 2.4L six by adding two more cylinders . Mercedes at one point had a 2 litre 4 cyl , 2.5 litre 5 cyl and 3 litre six - all basically the same engine with differing numbers of cylinders .
Lastly - 'boring or stroking' an existing engine to improve performance can result in strange displacements !
nicklonguk said:
Genuinely intrigued. Any engine designers out there with a view?
I'm a former engine designer, if that helps?Say a OEM has a need for a new range of engines. They might have a target capacity for one of them (complete with a tolerance to ensure it doesn't go over that target, so often nominally a bit smaller than they really want), but the rest of the range just needs to be biger or smaller than that target for marketing reasons. What dictates the capacity of the other engines in the family can depend on carry over tooling, block height, carry over piston, carry over crank, or pretty much anything else even down to the size of the stillages on the assembly line. Some of the reasons won't make sense to anyone other than the chap who controls the budget for the inspection equipment (or some other petty reason no one else cares about).
As long as the power/economy targets are hit and the capacity doesn't cause tax grief no one really cares what the capacity is for most cars except marketing people who will happily just tweak the boot badge to suit.
With the Ford 1.25 the extra digit made it sound more technical. Marketing. It was a 1.242 which in the old days would have been rounded to the first decimal place to be a 1.2.
Most engine capacities are a very peculiar number if you don't round them to the first decimal place in litres. Plus it's likely that the bore will be an integer number in mm (or some standard fraction of an inch) so the chances for that giving a nice round number for the capacity is tiny. Look at the engine in the GT86 - 86 stroke, 86 bore and the capacity is 1.998.
I am sure a lot of it, as well as regs, is to do with marketing. When I was a kid, the old had a 2.3 and it sounded very odd when most people were used to 1.6 and 2.0. So I am sure a rounded safe number is far more attractive to the world of non petrol heads out there, than an odd number.
I am sure that if my sister knew that her Lexus was a 2.2 and not a 2.0 (which appears to be the norm in diesels) then this might have put her off. Hence the reason it is kept off the badge and marketing?
Just a thought....
I am sure that if my sister knew that her Lexus was a 2.2 and not a 2.0 (which appears to be the norm in diesels) then this might have put her off. Hence the reason it is kept off the badge and marketing?
Just a thought....
The e30 M3 came with 2.3 or 2.5 litre engines but there was also a 2 litre version for the Italian and Portugese markets iirc.
There have been some strange sized engines in the bike world over the years, again driven by tax/legislation but also the race track.
Bike racing has also effected engine sizes, at one point everybody sold a 750cc sportsbike due to F1 & Superbike racing, now only Suzuki sell their GSX-R. The four Japanese manufactures now concentrate on their 600 & 1000cc sportsbikes as these are the most popular classes.
There have been cases where a manufacturer has changed an engines capacity by sleeving it down to race in a certain class, Ducati did this to take the 916 down to a 748.
The rules allowed a 750cc twin to race against 600cc fours in the SuperSport 600 class, when Triumph re-designed their 600cc four from the ground up it became a 675 triple which fitted right in the middle.
Triumph also sold an an 885cc engine which was iirc an over grown 750cc lump, they then bored & stroked the 885cc to create a 955cc engine and then when they needed some more torque it got stroked to 1050cc!
There have been some strange sized engines in the bike world over the years, again driven by tax/legislation but also the race track.
Bike racing has also effected engine sizes, at one point everybody sold a 750cc sportsbike due to F1 & Superbike racing, now only Suzuki sell their GSX-R. The four Japanese manufactures now concentrate on their 600 & 1000cc sportsbikes as these are the most popular classes.
There have been cases where a manufacturer has changed an engines capacity by sleeving it down to race in a certain class, Ducati did this to take the 916 down to a 748.
The rules allowed a 750cc twin to race against 600cc fours in the SuperSport 600 class, when Triumph re-designed their 600cc four from the ground up it became a 675 triple which fitted right in the middle.
Triumph also sold an an 885cc engine which was iirc an over grown 750cc lump, they then bored & stroked the 885cc to create a 955cc engine and then when they needed some more torque it got stroked to 1050cc!
nicklonguk said:
I was behind an old Nissan Micra today with a 1.3l petrol engine, and I remembered seeing an old Audi A6 with a 2.6 l badge on the back at the weekend.
Led me to think, what lead manufacturers to specify a particular capacity for their engine designs? Especially those "strange" sizes, like the zetec 1.25, various diesel 1.7's, 2.1 V6s etc.
Today you just seem to get standard even numbers- 1.0, 1.2, 1.4,1.6, 2.0, 3.0 etc. legislation must surely play a part, but what drove GM to use a turbocharged 2.8l for Saab Aeros and Vectra/Insignia VXRs? Why not 3.0?
Is there any engineering theory behind this? Why don't we see many "odd" engines sizes any more? (Alfa 1750TB is really a 1.8, can't think of any others in production. )
Genuinely intrigued. Any engine designers out there with a view?
The 1750TBI alfa is 1742cc so nearly a 1.7 !Led me to think, what lead manufacturers to specify a particular capacity for their engine designs? Especially those "strange" sizes, like the zetec 1.25, various diesel 1.7's, 2.1 V6s etc.
Today you just seem to get standard even numbers- 1.0, 1.2, 1.4,1.6, 2.0, 3.0 etc. legislation must surely play a part, but what drove GM to use a turbocharged 2.8l for Saab Aeros and Vectra/Insignia VXRs? Why not 3.0?
Is there any engineering theory behind this? Why don't we see many "odd" engines sizes any more? (Alfa 1750TB is really a 1.8, can't think of any others in production. )
Genuinely intrigued. Any engine designers out there with a view?
This is something that used to puzzle me back in the 90's when I first started being interested in cars.
In normal everyday Cars (Ford, GM, VW, BMW, Merc etc) petrol were almost always even numbers 1.6 1.8 2.0
Yet Diesels always odd, 1.7 & 1.9, hell even the E36 318Tdi had a 1.7 really.
I always assumed it was something to do with the way the engines were designed, but in recent years all the diesels seem to be even numbers again.
In normal everyday Cars (Ford, GM, VW, BMW, Merc etc) petrol were almost always even numbers 1.6 1.8 2.0
Yet Diesels always odd, 1.7 & 1.9, hell even the E36 318Tdi had a 1.7 really.
I always assumed it was something to do with the way the engines were designed, but in recent years all the diesels seem to be even numbers again.
Small Car said:
I am sure a lot of it, as well as regs, is to do with marketing. When I was a kid, the old had a 2.3 and it sounded very odd when most people were used to 1.6 and 2.0. So I am sure a rounded safe number is far more attractive to the world of non petrol heads out there, than an odd number.
I am sure that if my sister knew that her Lexus was a 2.2 and not a 2.0 (which appears to be the norm in diesels) then this might have put her off. Hence the reason it is kept off the badge and marketing?
Just a thought....
But it is on the badge? IS220? Unless I'm missing something?I am sure that if my sister knew that her Lexus was a 2.2 and not a 2.0 (which appears to be the norm in diesels) then this might have put her off. Hence the reason it is kept off the badge and marketing?
Just a thought....
P-Jay said:
This is something that used to puzzle me back in the 90's when I first started being interested in cars.
In normal everyday Cars (Ford, GM, VW, BMW, Merc etc) petrol were almost always even numbers 1.6 1.8 2.0
Yet Diesels always odd, 1.7 & 1.9, hell even the E36 318Tdi had a 1.7 really.
I always assumed it was something to do with the way the engines were designed, but in recent years all the diesels seem to be even numbers again.
If you were making a diesel version of an existing petrol engine and it needed to keep the same block height (for carry-over machining, assembly and also the cam drive) then the thicker piston crown (and probably piston pin too) would force you in to reducing the stroke, and therefore give you a slightly smaller capacity.In normal everyday Cars (Ford, GM, VW, BMW, Merc etc) petrol were almost always even numbers 1.6 1.8 2.0
Yet Diesels always odd, 1.7 & 1.9, hell even the E36 318Tdi had a 1.7 really.
I always assumed it was something to do with the way the engines were designed, but in recent years all the diesels seem to be even numbers again.
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