My obituary to the NA...and why I'll get over it. :D

[PhantomPH]

Alex said:

Many people confuse revs being below the boost threshold with lag.

I don't think it's a confusion - I think it's shorthand for describing the behaviour.

Obviously for a turbo to work, it cannot make boost right from idle - up the rev range it would be hopeless. But the rest of the engine is being engineered in such a lazy way as to rely on the turbo for power figures and in the real world that just means no proper power until high in the rev range...by which time your speed is either illegal or your gearbox is out of kilter. The gearbox will have to match a behaviour in order to do what it's supposed to and I just don't think they work well in this configuration.

Nothing in the lower revs and everything up the top - and gearboxes geared to give you...well...lord knows what, when it comes to auto/pdk/semi-auto.

[Twinfan]

PhantomPH said:

Obviously for a turbo to work, it cannot make boost right from idle - up the rev range it would be hopeless. But the rest of the engine is being engineered in such a lazy way as to rely on the turbo for power figures and in the real world that just means no proper power until high in the rev range...by which time your speed is either illegal or your gearbox is out of kilter.

Nothing in the lower revs and everything up the top.

That's not how I see modern turbos. They pull really well from low down, once the lag is out of the way, and have a flat torque curve but have limited top end revs. Response to your right foot, when the revs aren't up especially, is a bit 'elastic'.

NASP on the other hand just builds and builds up to the redline, has a more instant response to your right foot at all times but has less torque in the low to midrange.

Modern turbos encourage lazy low-rev driving with their easy-to-access torque, NASPs make you want to hunt down the redline. Very different characteristics.

[PhantomPH]

Twinfan said:

Modern turbos encourage lazy low-rev driving with their easy-to-access torque, NASPs make you want to hunt down the redline. Very different characteristics.

I think each is different. My S5 has little low rev pull and that's a hulking great V6. The real pull comes up the rev range when the turbo has most effect (although if the dash is to be believed, it does start supplying boost from surprisingly low revs)

[Twinfan]

More old-skool turbo by the sound of it!

[bcr5784]

Superchargers don't have any lag as they are mechanically driven off the engine. However they are generally more efficient at higher revs and tend to give the sort of rising torque curve of a NA engine.

[PhantomPH]

anonymous said:

[redacted]

Yeah, it's a shame. Which also introduces the supercharger into this discussion - why did they not replace the Turbo? Just requirements from the engine to be able to make them effective? I also really like the sound of a supercharger. That whine sounds awesome. One of the best I can remember was from the
VXR8 Bathurst.

[DJMC]

PhantomPH said:

Yeah, it's a shame. Which also introduces the supercharger into this discussion - why did they not replace the Turbo? Just requirements from the engine to be able to make them effective? I also really like the sound of a supercharger. That whine sounds awesome. One of the best I can remember was from the
VXR8 Bathurst.

Something to do with efficiency? Superchargers must have been around for 100 years but turbo power is "free", coming from exhaust gases, whereas superchargers are mechanically driven. However, I'm not so sure... every action has an equal and opposite re-action springs to mind?

[DJMC]

anonymous said:

[redacted]

That seems to have hit the nail on the head. I had no issue whatsoever with my DB7's supercharged straight six (its XJS chassis is another story) but got rid of my turbo'd TTS fairly swiftly due to its annoying lag and overrun characteristics, not to mention poor fuel consumption.

Maybe there will be a turbo "scandal" to come, as with the VAG diesel one?

[PhantomPH]

DJMC said:

anonymous said:

[redacted]

That seems to have hit the nail on the head. I had no issue whatsoever with my DB7's supercharged straight six (its XJS chassis is another story) but got rid of my turbo'd TTS fairly swiftly due to its annoying lag and overrun characteristics, not to mention poor fuel consumption.

Maybe there will be a turbo "scandal" to come, as with the VAG diesel one?

All sounds about right. I remember watching things where guys say, "This supercharger needs 100hp just to work" and never really bothering to think about what that actually meant beyond, "So you have to 'power' the supercharger in order to get more power in return".

[PhantomPH]

I think there has been a bit of a general 'bait and switch'-style scenario around diesels happening for a while - and we are now seeing the outcome. Remember not a million moons ago, diesel was much cheaper than petrol at the pumps. There was a subtle push to encourage people into diesel cars and stretch out that MPG. My Dad and I have talked about local air pollution being bloody awful (particularly where buses and trucks frequent) for years.

Now diesel is seemingly the devil. Surprise surprise! Don't worry, they will be back on the death of petrol as well, soon enough.

I think the American reaction is typical of the American reaction, TBH. VW owners saw the chance for a payout and they are doing all they can to get one. It's a HUGE bloody issue to them now and VW are monsters (notice they are a little less vocal and determined to get rid of guns...but I suppose guns are harmless, right?). Haha

Never underestimate the greed factor when it comes to 'uproar' in the USA. There was a chance to milk some cash out of VW and of course the most litigious society on earth is going to leap at that. Just look at the fact that more than 2,000 claimants have refused the $50,000 compensation package for their VW Rabbit that cost them next to nothing and are seeking more....

Of course harmful emissions should be kept to a minimum and every effort should be made to remove them all together. But I am almost 100% convinced that if you let the smartest minds in the automotive industry actually produce an engine the way they want without the stupid testing procedure, we would end up with a better, more efficient and more enjoyable motor under our bonnets.

[bcr5784]

I always thought the VW twin charger engine was a good concept. It used supercharger at low revs which was de clutched at mid revs where the turbo took over. Because the supercharger did not need to run at high engine rpm it could be geared to run much faster than on fully supercharged engines overcoming much of the superchargers low rev inefficiency.
Regrettably the implementation was bad and the engine was very unreliable and VW replaced it with a conventional turbo. (Actually a very good one where lag rarely intrudes because off boost performance is very good.)