Turbo engines revisited


#1

I have seen some old threads discussing the merits of turbo engines–specifically whether they will hold up. I am leery of these little 4-cyl engines pumping out 250 horsepower. Now, years later, is there any consensus on whether turbo engines hold up?


#2

Yes, they hold up. I’m on my 3rd turbo 4. The first making 185 hp sold at 85K, the second making 230 hp, sold at 108K and the current 220 hp at 32K. All ran strong with very little oil use and no engine issues when sold.

Turbo 4’s have been available almost constantly since the early 80’s from lots of manufacturers, foreign and domestic. It is a tried and true way of making hp when needed from a small fuel efficient engine. Very well known, reliable technology.


#3

Honda got 200hp out of a 4 cylinder without a turbo back in 1999. That was a big deal back then, but it’s not at all uncommon now.

In other words, it’s not like the turbo is doubling the horsepower. It’s usually a mild amount of boost that the engines can easily take.


#4

Actually it was 240 hp from the 2.0 liter 4… at 8200 rpm but only 153 ft-lbs of torque. I owned one. WONderful engine but not particularly fuel efficient. 27 mpg in a 2400 lb convertible sports car.

“Mild boost” is a matter of opinion. My first turbo car - 17.5 psi, the second, 13.5 psi max. Not sure about the current one. 11 psi or so, I believe.

Higher boost levels seem to be coming with every new model. The new 2.7 liter GM truck turbo 4 maxes at 22 psi! With a 10:1 compression ratio, no less. Ford’s Ecoboost 2.7 liter V6 pumps 17-18 psi boost to deliver 395 ft-lbs of torque. Even Honda’s Civic 1.5 liter turbo 4 is rockin’ 16.5 psi. The Civic R 2.0 liter 4 is boosted to 22.8 psi to achieve 306 hp. Whee!


#5

Quite right! For some reason I was thinking 100hp/L, but it was even better. :smiley:

Yeah, I know the levels seem high, especially to those of us who were boosting 90’s Hondas with all of 9 lbs, but there are also computer monitors today that weren’t around back then, and those computers won’t allow that much boost unless conditions are just right to do it without breaking things.

If you check out the Civic Si/Type R board you’ll see a bunch of people complaining that they don’t usually see anywhere near the advertised 20/23 psi, and that’s probably because the computer forgot to talk to the marketing department and is keeping the car within real-world safe parameters rather than the best-case-scenario output that the marketers glommed on to.


#6

Compare that to the 2.0L BMW turbo 4, typical of many turbo 4s:

HORSEPOWER (hp @ rpm) 248 @ 5200
TORQUE (lb-ft @ rpm) 258 @ 1450–4800
COMPRESSION RATIO 10.2

What really jumps out at me is the 258 lb-ft at a low low 1450 rpm, flat to 4800 rpm.


#7

Flat torque curves are the hallmark of well managed electronically controlled turbos. Peak boost down low, bleed a bit of boost off as the cam’s torque peak comes in and then peak boost again at higher rpms. Table top flat!

My Saab had a very wide torque curve without variable timing. All done with boost. As much fun as the Honda was to rev to 9000 rpm, wide torque curves make more drivable power.


#8

I’m a little skeptical of the new turbo engines providing more (or similar) gas mileage to larger engines when driven conservatively, more (or similar power), and the same reliability as the naturally aspirated engines they’re intended to replace. It would seem like something’s got to give assuming there’s no free lunch.


#9

@Scrapyard_John My personal experience has been that a 2001 boosted 2.3 4 cylinder making 230 hp can give an easy 30 mpg in a 3900# car and still run 15.2 seconds in the quarter mile. And now my 2014 boosted 2.0 liter 4 making 220 hp returns 35 mpg pushing 3850# and has similar performance.


#10

My worry is that there has to be more pressure on the bearings, more stuff trying to get by the exhaust valves and rings. Seems like the metal just couldn’t hold up as well. But–maybe it does.


#11

VW/Audi managed to make turbo engines with all-aluminum blocks and holds together… more or less :slight_smile:
I would not be afraid of moderately turbo-charged engines having more time-proven cast iron cylinder sleeves.


#12

That is the same strategy Mack used in 1966 when it came out with the Maxidyne 6 cylinder 672 cubic inch turbo engine,The 6 cylinder 855 cu. in. non turbo Cummings had most of the truck market locked up.

The Cummings rpm range was 1800 to 2100 rpm. This usually required a ten speed transmission although I have seen some eight speed ones.

The turbo Mack operated from 1200 to 2000 rpm, more than twice the rpm of the non turbo Cummings and with maximum torque and boost at 1200 rpm with the torque curve being almost flat to 2000 rpm. This allowed the use of just a straight 5 speed transmission.

The 237 hp Mack would run away from a 250 hp Cummings or a 318 hp Jimmy unless the land was as flat as a pancake.


#13

I have a 2016 Hyundai Veloster turbo, it is a 1.6 and I believe has around 200 HP’s.
It is also a direct injection engine which is probably more of a problem.
I have over 30K miles on it. I use Synthetic oil and change it every 3.5K miles. I know it is overkill but that is what I do.
It is not burning any oil-yet. The turbo is fine. Over the last 10K I have some pinging under load that goes away if I use premium or mid-grade fuel. I don’t know why manufacturers insist that their car can use regular gas.
I might try one of those placebo intake cleaner sprays (CRC) to see what happens to the pinging.
I plan to keep the car well past 100K miles, so will keep all posted :slight_smile:


#14

Just because an engine is turbocharged, or even supercharged, does not mean the engine is in the boost all the time.
Normal driving and regular oil changes should mean things are going to be fine.


#15

See the Consumer Reports article, “Troubles With Turbo Engine Reliability” in the 12/2018 issue of CR and also available on line to subscribers. It includes a chart based on their reliability data of turbo engines and their transmissions, comparing them to “average non turbo reliability.” Many makers’ turbos (Lexus, Honda, Porsche, BMW, Audi, Subaru) were all above that average. Other makers had some turbo engines/trannies above that average and others below. Only Mini had all (both) of their turbo engines/drivetrains below that average.


#16

Regarding fuel economy, seems like several recent turbos do quite well, including Honda’s 1.5L and 2.0L and VW’s 1.4L.


#17

" According to owner reports of problems, and CR has literally hundreds of thousands of owner reports to mine data from, cars from Honda, Lexus, Porsche, BMW, Subaru, Audi, Mazda, Mercedes-Benz, and Infiniti with [turbo engines have fewer problems than the average non-turbo engine does" Read more about modern tubos at BestRide if interested, or jump right to the Consumer Reports analysis here. I think you need to be a subscriber to read it though. Not sure.


#18

The December 2018 issue has that article and is in most public libraries. I subscribe to CR on paper and on line; not sure about on line access for nonsubscribers but it’s a good article and worth a search.


#19

I was especially impressed by the Car and Driver long term test of the Accord with the 2.0L turbo. 30 mpg average actual (they drive their cars hard), and it did 0-60 in 5.7 seconds. A few years ago that was high performance car territory.