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!
