Does boost lag add character?

Colin
By Colin Wood
Mar 11, 2022 | Turbocharging, Boost Lag

Photograph Courtesy BMW

Many cars on sale today come straight from the factory with a turbocharged powerplant. Some people use it for economy, while others use it for sporting pleasure.

Regardless of the intended use, though, many of these engines all share one feature: an almost total lack of turbo lag.

Is the nearly instant boost of modern setups an improvement? Or do the old-school turbo systems that need time to spool up add a certain charm to some cars?

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Comments
Driven5
Driven5 UberDork
3/10/22 11:46 a.m.
Colin Wood said:
 

Is the nearly instant boost of modern setups an improvement? Or do the old-school turbo systems that need time to spool up add a certain charm to some cars?

Yes.

z31maniac
z31maniac MegaDork
3/10/22 12:00 p.m.

I prefer the newer stuff. The big hit of power may feel exciting, but it makes the car more of a PITA to drive. 

Streetwiseguy
Streetwiseguy MegaDork
3/10/22 12:08 p.m.

My six cylinder twin turbo XC90 doesn't feel fast, but it can certainly get you where you need to go quite quickly, with no perceptible lag.  The same vehicle with the single turbo five is slower, but has that ever so enjoyable rush of acceleration when the turbo spools.  I kinda like the five better.

Professor_Brap (Forum Supporter)
Professor_Brap (Forum Supporter) UberDork
3/10/22 12:13 p.m.
Driven5 said:
Colin Wood said:
 

Is the nearly instant boost of modern setups an improvement? Or do the old-school turbo systems that need time to spool up add a certain charm to some cars?

Yes.

Yes, there is something absolutely intoxicating about driving something laggy. Also modern cars are so fast and easy to drive it's a riot. 

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
3/10/22 12:18 p.m.

Lag sucks. Give me throttle response over horsepower in that case. Best of all is throttle response WITH horsepower.

paddygarcia
paddygarcia GRM+ Memberand Reader
3/10/22 12:41 p.m.

Who doesn't like non-linear throttle response with hammer-like qualities, especially at the apex in the wet?

Me, for one.

Colin Wood
Colin Wood Associate Editor
3/10/22 12:43 p.m.

In reply to Driven5 :

I couldn't agree more. Modern cars are really good because they have almost no flaws, but, as I've gotten older, those flaws are what give a lot of older cars character.

obsolete
obsolete GRM+ Memberand HalfDork
3/10/22 12:53 p.m.

In reply to Colin Wood :

"It's better, because it's worse." - Jeremy Clarkson in some old Top Gear episode, I think

codrus (Forum Supporter)
codrus (Forum Supporter) GRM+ Memberand PowerDork
3/10/22 12:57 p.m.

"character" is the things that a car does that are less than perfect, so sure.

OTOH, the downside to modern "zero lag" turbos is that one of the ways they achieve this is by being undersized.  Most modern turbos are there so that they can sell you a 2.0L I4 with the same power specs as the 3.0L V6 they used to have, while getting better EPA fuel mileage.  This is a recipe for a boring engine that spools up quickly and peters out above 4000 RPM.  Whether it be a modern turbo engine, an old-school V8 with crappy heads that don't flow, or a diesel, I'm not a fan of that kind of torque curve in a sport-ish car.  (diesels are great for tow vehicles, OTOH)

There's also something really entertaining about a car where the torque triples between 3000 and 4000 RPM. :)

 

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
3/10/22 1:05 p.m.

But there are good character traits and bad character traits. A big laggy turbo is a bad character trait. An engine that takes a bit of time to warm up before it runs perfectly is a better one. 

Modern engines are able to take advantage of much more sophisticated engine management, so you don't need to run an 8:1 compression ratio to keep the engine from detonating. If you can run a 13:1 static compression ratio and vary the effective compression ratio with VVT and then toss in complete control over the throttle plate, you've got lots of energy to spin up a big turbo. The BBR turbo kit for the ND Miata fits that description - it spools faster than the supercharger available for the platform but has enough headroom for 400 hp on a 2.0. So it's not just as simple as "use a small turbo, it'll spool faster".

My old 323 GTX had character out the wazoo. It was a cute little hatchback that thought it was a rally car. But the laggy turbo was the exact opposite of endearing, it was annoying.

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