rev up your engines, today I'm going to talk about why not to by a variable
compression ratio engine, and to understand why I say that, here's a
little history lesson, displacement on demand engines, to get power when you
want power and better gas mileage when you want better gas mileage, have been around for a
while, in 1981 Cadillac made the first
production engine that was called the L62 v8 6-4 it could run as a v8 for full
power, then turn to six cylinders and even four cylinders, but alas it was a
massive failure, and the engines tended to fall apart after a short period of
driving, and as time went on, electronics got better, in 2005 GM tried
it again with a 5.3 liter v8 LS4 engine, where half the cylinders could be
shut down when you had low power demands, really the cylinder deactivation systems
they're pretty much a massive failure, but now they're making variable
compression engines, that have varying compression ratios inside, now in itself
this isn't a new idea, they've been around for a long time, they were test
engines they weren't engines they put in cars and people drove around, and yes
it's very interesting technology, but as for myself I don't want to be a guinea
pig, spend a bunch of money for some engine that they're just trying out and
find out that, whoo they blow up after a certain period of time or they have
significant driving problems who knows, the first production variable
compression engine, is the Infiniti qx50 it's a 2.0 turbocharged four-cylinder
engine, that can change its compression ratio from eight to one all the way up
to fourteen to one, as you can see in this animation, instead of having a
piston and a rod that goes right to the crank, it has various different
angles which can adjust how much compression is in the engine, all these
moving parts are just things that are going to break down over time, I mean let's
look at it logically, you have a piston and a piston rod in a
normal engine this bolts to the crank and it goes up and down and up and down
and up and down, simple designs been around for 100 something years reliable, I
mean really, do you want to replace the simple system that has a piston and a
rod, to one that has a piston, a rod, then other rods, cantilever system, another rod
and then a computer-controlled servo that adjusts how high and low it goes
now yes the variable compression engine that Infiniti has out, does get better gas
mileage it's 27% better than the old 2-liter non variable compression engine
and it certainly beats the heck out of GM cylinder deactivation which only got
five to seven percent better gas mileage, but really when you got an old system
that's totally dependable, if you want to make radical changes, I think that you go
radical changes for completely different types of engines, not four-stroke
gasoline engines or even two-stroke gasoline engines, if you're going to use
that much technology, you might as well give up with gasoline engines and do
something else, rather than modify gasoline engines with all these crazy
designs, where computers control the lift of the Pistons and hey, you know that
what's going to break it always does, look at Nissan they have a history of
problems, the company almost went bankrupt, and since Reno and Nissan
merged, hey their quality has gone, so it's kind of fascinating that that's the company
that's bringing out the first variable compression engine to sell to the public
I'm not against technology, but I like my technology to actually work, personally
I'd wait a while till those things have been out and tested, Toyota starts making
them and they start selling them by the millions, and then over the years they're
proven to be reliable engines, yeah I'll buy one then, but since I'm not a
fortune-teller, hey I'm staying away from these variable compression ratio engines
until they prove their worth, and really what are you getting for all this
technology, the Infiniti hey it's combined economy it's only 26 miles a
gallon, that isn't that great gas mileage when you think about it, and that's the
rated gas mileage, everybody knows you always get worst gas mileage than what
the ratings give you, so really I'll give a pass on these variable compression
ratio engines, till things change and maybe they will
but I'm not betting my bank on it, so if you never want to miss another one of my new
car repair videos, remember to ring that Bell!