Does Size Matter? Engine Displacement….How Low Can They Go?

JTK said:
I love the little LYX 1.5T paired to a the 6AT in my 2021 Equinox. I'm sure it's tiny turbo spins it's little heart out, but you wouldn't know it. It's smooth, quiet and has great power and economy for what it is. I average 30-34mpg tank to tank and it's AWD. I can point to threads over on GM/Equinox forums I'm on that has owners that claim to have 200-300K miles on all original 2018+ GM LYX 1.5Ts.
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Good to know I picked up a 24 Terrain and its been fine for daily commuting. Mine is front wheel drive and gets about 25mpg in heavy heavy san antonio traffic with AC always running.
 
JustinH said:
Good to know I picked up a 24 Terrain and its been fine for daily commuting. Mine is front wheel drive and gets about 25mpg in heavy heavy san antonio traffic with AC always running.
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Nice! Yours has the latest LSD 1.5T, so you don't have the cam driven vacuum pump to power the vac booster for the brakes. There is no vac booster on 2023+ as they went all electronic for the brakes. Be sure to do dump/fills often on that 9AT. Very easy to do.
 
I think the Honda 600 sedan used a detuned Honda 450 motorcycle engine.
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IndyIan said:
All "working" diesel engines with turbos, are using them nearly all the time, and are making power efficiently, so there are no big non-turbo diesels left, as they are too inefficient.
In theory, these small gas DI turbo engines should work the same , but are not so good in reality for some reason? Maybe they are made to game the EPA mileage test, but fail in real life with not so great 87 octane, so they want to ping, and then have to run super rich not to blow up?
I do find it interesting that the "big" 2.5 NA(all with AWD) in the Subaru family matches or beats these GM fwd SUV's in mileage, if not at the drag strip.
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It is more complicated than just displacement.
BMW 330 doesn’t have any issue to push above 40mpg on interstate. In the city, it can deliver high 20’s or above 30. It is combination of engine sophistication, transmission and aerodynamics. Cheap cars won’t have ZF8 and all the valvetronic and VANOS goodies on the engine, super efficient injectors, dual cooling system with water cooled intercooler etc. That is why many use gas like V6 when pushed.
Our Tiguan is perfect example how transmission can screw up mpg. When my wife drives, 27-29mpg in town, no issues! Me? 21-22 at best. When driven slow, transmission does good job shifting appropriately. Driving harder? Transmission holds gears unnecessarily, losing momentum etc.
From 2012 to 2015 I had VW CC with same engine, extra 100lbs, but DSG transmission. Pulling 26mpg in city when I drive was easy peasy, and this car wanted to move as DSG was really, really good. On interstate 34mpg was like nothing.
 
The smallest one I has was a 1974 B210 with the A13 4 cylinder 1288 cc engine that made 75 SAE net HP. That kind of power was less than the 3 cylinder turbos available now so I got to experience the attributes of a small power output. 0 to 60 in about 17 seconds. Good thing there weren't too many on ramps back then. Still, it had a 4 speed manual and was a hoot to drive.

The 3 cylinder turbo Trax has almost twice as much power and does 0 to 60 in less than 1/2 the time. I could deal with that in a small city or town.
 
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IndyIan said:
All "working" diesel engines with turbos, are using them nearly all the time, and are making power efficiently, so there are no big non-turbo diesels left, as they are too inefficient.
In theory, these small gas DI turbo engines should work the same , but are not so good in reality for some reason? Maybe they are made to game the EPA mileage test, but fail in real life with not so great 87 octane, so they want to ping, and then have to run super rich not to blow up?
I do find it interesting that the "big" 2.5 NA(all with AWD) in the Subaru family matches or beats these GM fwd SUV's in mileage, if not at the drag strip.
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Turbos make more hp under the curve, and sometimes use fuel to cool the charge and run rich. They have the potential to be more fuel efficient when kept out of boost, but most drivers don't have the right foot mod.
 
Lots of cars with small displacement

First Subaru sold the 1970 360, Honda N360 and the original Suzuki 4wd had 360cc engines

Later Hondas were 600cc

Saab 92/96 were small displacement 2 cycle cars

Smart cars had small displacement

Honda Insight
Yugo
Chevy Sprint, Suzuki Swift, Geo metro
Ford Fiesta
Mitsubishi Mirage
Daihatsu Charade
All had 1 liter engines (mirage 1 was only overseas)

All this is before getting into micro cars, king midget, Austin Healy, Messerschmidt, etc, etc etc

Above 1 liter is all manner of nonsense
Buick, Chevy seem fixated on 1.2,1.3,1.4,1.5 liter engines in all manner of vehicles
 
zzyzzx said:
Feel free to correct here:

I know that tiny engine like this probably aren't going to last as long, but given the smaller size isn't it going to make it much easier to DIY replace the engine?
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A small displacement does not always mean small size. Size difference is noticed between an inline 4 VS a V6.

But if talking just 4-bangers - A 1.3T may be same physical size as a 2.0/2.5L N/A. And may be harder to DIY since it has more components to deal with, such as everything related to forced induction.
That being said - my 2015 FIAT 500X was easy to DIY on that 1.4T and 6MT. Lots of space, and I easily reached 43MPG, while still having great passing power. The new 1.2T Chevy/Buick should take notes on such performance, MPG, and serviceability. I've seen a few of these little GMs with whole front end blown apart at dealerships just to perform maintenance or replace a sensor. Not DIY friendly at all.
 
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2strokeNorthstar said:
When I had a 65 VW bug it started off as a 1.2l 40hp. Pretty crazy. I had a full race 550cc jet ski that made 80+hp
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Man I got caught passing 4 18 wheelers (or whatever is equivalent in Europe) with this:
1.1ltr, 55hp. Not sure how many of those horses were alive. The cop on BMW motorcycle kind of didn’t have issues catching up.
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ATex7239 said:
I think this is a better argument. Yes there is a break over point where the smaller displacement turbo engine is less efficient than its larger NA counterpart.

Ex: Two previously owned Ford Fusions - 2.5 NA with average MPG in the low 30’s and 1.5T with average MPG in the high 20’s.

Basically owned two of the exact same vehicle body wise however the one with the smaller turbo engine did significantly worse in real world MPG.
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Yep my old 91 & 92 Oldsmobile Cutlass Supremes w 3.l1 would get low 30s mpg's on the freeway and my current 07 Impala w 3.5l gets about the same but does get better city than the Olds
 
Number_35 said:
A friend in high school had a '60, I think 1200 cc and rated at 36 HP.

No oil filter - her dad said VW recommended an oil change every thousand miles.
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I think the 36 horse had more torque than the 40 horse...
The engine used an oil strainer that you cleaned with every oil change. External filters came later from the aftermarket.
The center oil plug drained the oil and the 6 nuts held the strainer.
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JeffKeryk said:
I think the 36 horse had more torque than the 40 horse...
The engine used an oil strainer that you cleaned with every oil change. External filters came later from the aftermarket.
The center oil plug drained the oil and the 6 nuts held the strainer.
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And the single port heads/intake manifolds were so restrictive you couldn't over rev the motor.
 
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