Small Turbo vs Large Naturally Aspirated Engine

[MrHorspwer]

Two of the last three vehicles my wife leased were Chevrolet Blazers.

Blazer 1 had a 3.6L V6. Blazer 2 had a 2.0L turbo 4.

3.6L: 308hp@6,600 RPM, 269lb ft @ 5,000 RPM
2.0L: 230hp @ 5,000 RPM, 258 lb ft @ 1,500-4,000 RPM

Obviously much more HP from the V6, but similar torque at a much lower RPM for the turbo.

The 2.0L was an absolute dog compared to the V6. Like, not even a contest. At any speed, any RPM, any situation, the V6 had power on tap where the 4-cylinder didn't.

Maybe had I never driven the 3.6L, I would have been more tolerant of the 2.0L. After having the V6 first, moving to the turbo was a disappointment.

She's in an Equinox EV lease now. It's better than both.

 

[slacktide_bitog]

LSPI and fuel dilution in many of those small turbos

Transverse V6 engines are often impossible to work on

Turbos require premium (even if they say you can fill with regular, it's still not a good idea), while most non-turbos can use regular (there are a few exceptions though, mostly those with high redlines)

 

[Dinoburner]

A relative in northern VT had the 2.7 turbo in a Silverado and she hated having to stab the throttle to get moving.

 

[meep]

I really like small turbos 2.0 and up, the low end torque really helps drivability.

This, for me.

I’ve had a low pressure turbo in a gen 1 s60 Volvo, and that did it. the twin turbo ford 2.7 which followed was a delightful motor, and the Tacoma I have makes excellent use of its small turbo. There was a 1.5t civic in the family which was also a delight (manual trans).

All of these are smaller displacement motors, obviously.

 

[Oillover]

So, ideally, what you are looking for is a straight 6 for smoothness, and good idle (low speed efficiency), with a turbo (or two) for the high end horsepower.

I'm pretty sure Mercedes and BMW already figured that one out!

If I ever buy another car, that's the setup I'd want.

You and I both!
While I enjoy the turbo B48 from BMW, the B58 has a well-earned reputation.
Recently I spotted a 2016 340i for sale in a beautiful blue.
The only downside was the higher mileage (near 100k miles).
The following morning it was already sold.

 

[Carmudgeon]

As already noted, turbocharged engines can be tuned to have better torque characteristics, and are easier to tune to make more power.

Whether that's more "fun" than a NA engine, especially a peaky one, is subjective.

In practice, I've found that driven spiritedly, turbo engines sacrifice whatever efficiency advantages they claim.

And for those who keep their vehicles for the duration, there is also the presence of an additional major component that is subject to wear, and repair/replacement.

That said, I wouldn't rule out a turbo just because it is a turbo, and they are harder to avoid now.

 

[spk2000]

if your looking for a long life vehicle avoid the turbo anything. Increaased pressures lead to increased wear , oil leaks, etc which kills the engine sooner with the possibility of costs for a failed turbo too

 

[K2K2]

So, ideally, what you are looking for is a straight 6 for smoothness, and good idle (low speed efficiency), with a turbo (or two) for the high end horsepower.

I'm pretty sure Mercedes and BMW already figured that one out!

If I ever buy another car, that's the setup I'd want. Not to take anything away from the 2.0 T 4cyl, but that 6 could be a dream to drive.
133 mph in a 2.0T, with plenty of low end torque always amazes me, and it will also give you that V6 thrill too.

Don't forget - Mazda has a straight 6 turbo also!

 

[skyactiv]

My wife's BMW has a 2.0 twin scroll turbo and is a mild hybrid with an 8 speed automatic. The hybrid mask any turbo lag and the transmission is dialed in perfectly. It supposedly does a 13.9 1/4 mile. The only thing I dislike about her car is the brake feel.

That being said, I don't have the same feeling for her BMW as I did years ago for the 3 series of old.

Other notes, my VW Jetta GLI has a 2.0 turbo and a 6 speed manual. My GLI has lousy engine braking. My wife once had an Accord Coupe V6 with a 6 speed manual and that car had excellent engine braking.

 

[meep]

As already noted, turbocharged engines can be tuned to have better torque characteristics, and are easier to tune to make more power.

Whether that's more "fun" than a NA engine, especially a peaky one, is subjective.

In practice, I've found that driven spiritedly, turbo engines sacrifice whatever efficiency advantages they claim.

And for those who keep their vehicles for the duration, there is also the presence of an additional major component that is subject to wear, and repair/replacement.

That said, I wouldn't rule out a turbo just because it is a turbo, and they are harder to avoid now.

Good stuff.

I’ve got solid respect for how Volvo pulled it off. They already had a stout block in their 5 cylinder. They lowered the compression ratio and added a low pressure turbo - and with reasonable care theres s60s rolling with a quarter million miles on them with the original turbo, head gaskets, etc. granted, those were lower performance mills, and probably lower rpm turbos as well - as pressures were usually capped at 6-7 psi and still had lag - but it showed it could be done with longevity in mind.

 

[AZjeff]

1.6T with a stage 2 tune are just "livable"as far as broad performance. If possible, 2.0T is the best starting point.

Not sure I agree. The 1.5T in the Equinox is way more livable than the 2.5 NA in the 2015 RAV4 we had and it was more than adequate.

Your point of view with your Kona street racer is different than mine with "the wife's car".

 

[NormanBuntz]

I've had a 1984 Saab 900 Turbo and a 2005 Mazda Miata Turbo. I'm age 74 and I'll prefer a regular V-6 every day.

 

[Mainia]

Not sure I agree. The 1.5T in the Equinox is way more livable than the 2.5 NA in the 2015 RAV4 we had and it was more than adequate.

Your point of view with your Kona street racer is different than mine with "the wife's car".

Yep

 

[Exhaustgases]

NA, 45 to 50 mpg and 50 Hp and no problems in 25 years works for me. If you tow something that is a different discussion.

If there was no traffic mess and the speed limit was like the autobahn, then things would change for me car wise.

 

[tcp71]

It’s amazing what is happening with 2.0 turbos.

https://en.wikipedia.org/wiki/Mercedes-Benz_M139_engine

Production vehicles with 450+ hp out of a 2.0liters. 330 ft lbs of torque @2000 RPM.

 

[Jetronic]

Is the low-end torque of a small turbo engine higher than that of a larger naturally aspirated engine when both produce the same hp?

yes, but not usually right at idle. But you will only be in that rpm range when you start from a stop and if you use all the torque you just get tire slip.

For towing, and especially getting going on a hill, a big NA engine is better. Best is a big engine with a turbo.

 

[Delta]

yes, but not usually right at idle. But you will only be in that rpm range when you start from a stop and if you use all the torque you just get tire slip.

For towing, and especially getting going on a hill, a big NA engine is better. Best is a big engine with a turbo.

Meh, I don't know. A town over to get there there's a fairly steep mountain pass (nothing like in Colorado or the such, but still steep) and I've found the little turbo 4 pot in my Tacoma just casually climbs it 2,000 RPM's whereas my previous 3.5L V6 Tacoma's were screaming 3500+ to get the same speed. Engine braking is much better on the down-slope too.

 

[Jetronic]

Meh, I don't know. A town over to get there there's a fairly steep mountain pass (nothing like in Colorado or the such, but still steep) and I've found the little turbo 4 pot in my Tacoma just casually climbs it 2,000 RPM's whereas my previous 3.5L V6 Tacoma's were screaming 3500+ to get the same speed. Engine braking is much better on the down-slope too.

Yes once you're moving, the turbo is at an advantage. It's when you're stopped, and need to get a heavy weight moving again that you need loads of torque near idle. Especially in a manual or dct equipped car.

My 1.5T is the worst (as in nothing noticeable) at engine breaking I ever had. my 2.0 diesel was the best. it did better with fuel aswell, but not to a very great degree.

 

[Delta]

Yes once you're moving, the turbo is at an advantage. It's when you're stopped, and need to get a heavy weight moving again that you need loads of torque near idle. Especially in a manual or dct equipped car.

My 1.5T is the worst (as in nothing noticeable) at engine breaking I ever had. my 2.0 diesel was the best. it did better with fuel aswell, but not to a very great degree.

I've never towed with my current truck, but did tow with one of the 3.5 V6 Tacoma's. It definitely required you to put your foot in it to get it going. I would suspect the new one would handle this a little better.

The 1.4T in my grandmothers Jetta had pretty poor engine braking. The FA20DIT in the WRX is acceptable, but is a manual so the driver does have some input in that.

 

[Jetronic]

I've never towed with my current truck, but did tow with one of the 3.5 V6 Tacoma's. It definitely required you to put your foot in it to get it going. I would suspect the new one would handle this a little better.

The 1.4T in my grandmothers Jetta had pretty poor engine braking. The FA20DIT in the WRX is acceptable, but is a manual so the driver does have some input in that.

The problem with lower idle torque is you will burn the clutch trying to get going if you need to rev high. If it's a 2wd you can probably dump the clutch and wheel slip until you are up to speed, but that's not really an option with AWD. You want to be able to engage the clutch completely at the lowest possible speed. getting from 0 to 4 mph and being safe from destruction is a lot better than needing to get to 10 mph. You might not get there in time.

It's not an issue with a traditional torque converter automatic