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 …
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.
I prefer the newer stuff. The big hit of power may feel exciting, but it makes the car more of a PITA to drive.
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.
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.
Lag sucks. Give me throttle response over horsepower in that case. Best of all is throttle response WITH horsepower.
Who doesn't like non-linear throttle response with hammer-like qualities, especially at the apex in the wet?
Me, for one.
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.
In reply to Colin Wood :
"It's better, because it's worse." - Jeremy Clarkson in some old Top Gear episode, I think
"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. :)
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.
Many, many years ago, I had an MR2 Turbo while out in L.A. and, of course, I took it up to Mulholland Drive. Riding the lag through the turns felt like surfing.
Character isn't better, it's just character
Lag is fine if the car isn't meant to turn
I get to play engineer with my V12. I tried to use the turbo charts to figure out what would be best but got bogged down between drag racing , autocross and road racing. I spent hours watching UTube, reading books and magazines.
Just when I thought I had the answers I'd ask around to confirm only to find out that little information applied and I couldn't figure out which.
On advise from a friend I'm putting a pair of T3's on and he's got all sorts of bits and pieces I can trade him for. Since mine are new if we got the housing wrong it's just unbolt the hot or cold side and trade a pair from him.
He says that the size he selected is what he doesn't have so he's happy to trade. I'm actually comfortable with this approach. Try and adjust,
We'll make passes at the drag strip, runs at the autocross and then go to Elkhart Lake. If I blow a head gasket or something. So what, I've got spares.
Ive watched Calvin Nelson on the dyno and drag strip so hopefully my approach is going to result in decent reliable performance.
I don't know how much dyno time I'll buy, I'm sure not as much as the Nelsons do. But I'll concede his superiority and maybe stay under 14 psi . The first time maybe stay under 6 psi.
If you don't have to wait for boost, is it even there?
Isn't boost lag the time it takes to downshift a gear or too? 
I'm with Keith on this one. Years ago I drove a first year 911 turbo and the lag was indeed annoying and that was on a track. I can ony imagine how annoying it would be on the road. It wasn't as pronounced as the early 80s turbo Capri but it was still annoying.
Keith Tanner said:Lag sucks. Give me throttle response over horsepower in that case. Best of all is throttle response WITH horsepower.
Quoted for truth.
I had a chance to drive a big turbo FD. Below 4500 it had all the power of a lawnmower. Above 4500 it had all the power of a carrier launch. The transition was violently horrible. It was a hateful car to drive.
I would not want to confuse powerband with lag. A turbo that hits late and hard is just sized that way. Laggy turbos accelerate slower than the engine does - they lag behind the engine.
Ever drive a car that built no boost in 1st gear because the engine accelerated too quickly?
I like my tiny turbo spooled up hella early. Feels more linear.
In reply to Pete. (l33t FS) :
Agreed, there's a difference between spool time and lag. Spool time can be a little entertaining - it's like an engine coming on cam. Lag sucks. It's like having a rubber band for a throttle cable.
Character is how you describe something you know is wrong
In reply to mke :
Doesn't mean it can't be endearing.
I do love a healthy bit of turbo lag and so do pencil thin connecting rods.
The funny thing is, the turbo in the S60R feels like a big-block rush of torque at any RPM... on the street.
When I rallycrossed it, the little bit of delay was maddening.
I suspect that 2-3 decades, the idea of any kind of internal combustion engine in a car will be regarded as "character".
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