[Closed] Car - Good idea or mechanical stupidity?

Do rally cars not have an anti lag system that keeps the turbo spinning anyway

I think this is called a compound turbo, coming to f1 next year.

It already exists, can't remember who, but one of my clients has it.

Would this not be redundant-ish because of the idea of sequential turbos? Obviously they're not the same thing, but that idea of a small turbo that spins up rapidly, leading into a larger one with more boost, into a third potentially (as with BMW's 550d engine)?

Pretty sure Audi do/are going to do this on their diesels?

Turbo lag on a modern engine is minimal such that if you're experiencing it you"re not driving properly. If you're in too high a gear you'll get lag, if you're in the right gear then lag is negligible. Turbocharged engines are far more efficient as they're utilising energy that would otherwise be wasted.

Modern cars are less leggy cause the use smaller turbos. This is possible due to modern electronic engine management systems that enable the use of turbos with higher compression ratio engines while the engine management system can control knock (exploding air/fuel mix rather than burning air/fuel mix). Even later development is direct injection, a technology that suddenly pulled Diesel engines out of the Stone Age, is now starting to be introduced which will further enable lag to be defeated. Back in the '80's when engine management systems were quite basic you had to reduce the engines compression ratio to avoid knock meaning larger turbos to increase the flow rate, which meant very leggy turbos.

Also turbos generate more torque, and it is torque that is more important as it means you can push bigger gears, hence better efficiency and acceleration.

The anti lag mechanisms work in various ways, but the best is the variable vane set up which is better than a complicated, heavy and expensive twin sequential turbo set up. Other methods include introducing fuel into the exhaust manifold which is burned to increase exhaust manifold pressure, but clearly this requires some pretty advanced materials in both the turbos and the exhaust manifold to handle the high temperatures and is prohibitively expensive for normal road cars.

Contrary to popular belief a turbo does not act like a windmill. You're not trying to 'blow' gas through it as high speed. Turbos use the expansion of a hot gas to extract the heat energy out of the exhaust gas. The hot exhaust gas is at a high temperature and pressure at the turbo inlet with a very slow speed -almost zero. The hot gas then expands as it passes through the turbo and cools as it does so. It is the expansion and acceleration of the gas from almost zero to a very high velocity as it expands that drives the turbo. So minimising turbo lag is not not about 'keeping the turbo spinning', it's about maintaining gas pressure and temperature in the exhaust manifold.

I suspect the F1 cars will be using direct injection engines with variable vane turbos and some form of fuel injection into the exhaust manifold - but they're less concerned about lag as they are keeping the engine speed high which maintains exhaust gas flow which in turn maintains exhaust gas pressure.

So in answer to the original question, turbos are a very elegant solution. Normally aspirated is just inefficient and superchargers are plain stupid as they take more energy out of the engine rather than utilising energy that would otherwise be wasted, thus further reducing efficiency.

This is what twin turbos do isnt it?

Turbo lag on a new car is almost un-noticable, plus with a NA engine you have to wait for peak power and torque to arrive, whereas with the turbo the power is just so accessible.

I love the NA straight 6 in my car, but you have to rev the balls off it to get the performance, but in the turbo straight 6 I have just ordered the peak torque is 1300 rpm, so its moving urgently throughout the rev range

🙂 😉

Turbo = easy to drive quickly
NA = nice to drive quickly

IMO of course.

oldnick - hit it on the head!

I understand turbos work etc but I want them as nice as NA engines. For fun driving not just race courses

[i]Turbo lag on a modern engine is minimal such that if you're experiencing it you"re not driving properly.[/i]

Says the man that has probably not driven a decent non-turbo engine as a comparison - or a fast motorbike for something with instant acceleration at any revs.

Electronic compound turbos - pretty much lag free.

They are going to be released by the VW group next year I think. Also the next BMW M3/4 has a new induction system with extremely low inertia.

Modern turbo diesel and petrols are pretty lag free with high torque in the 1200-1800rpm range

oldnick - Member

Turbo = easy to drive quickly
NA = nice to drive quickly

Turbodiesel- easy and nice to drive quickly. While leaving satisfying clouds of smoke, like a rocket.

I drive one of these VW twincharger engines and it is really weird how quick it is to pick up once the accelerator is pressed.

I used to have a really quite 'old school' turbo engine in my Subaru Impreza. That would need a completely different driving style than a normally aspirated engine and I can see the difference. Mind you, unlike WCA, I actually MUCH prefer a turbo engine to an NA one...

Rachel

Says the man that has probably not driven a decent non-turbo engine as a comparison - or a fast motorbike for something with instant acceleration at any revs.

I used to have an FZR1000 Yamaha. I find the response of a turbo diesel acceptable. It strikes me as unreasonable to expect a 1.9 Golf to go like an eXup, so I can't really understand your point.

Are you trolling STW and [url= http://www.pistonheads.com/gassing/topic.asp?h=0&f=23&t=1337467&mid=0&nmt=Good+idea+or+a+complete+lack+of+mechanical+knowlege ]PH[/url]?

Both places have their recurring topics and this is a common one on PH.

superchargers are plain stupid

😯

I've not driven any turbo engine that gives the same crisp throttle control of a good normally aspirated engine.

If you drive a modern diesel or petrol turbo car properly you really shouldn't notice much lag and the little there is can be made to work for you (creeping through crap traffic or slow manoeuvres).

I like turbo and na cars of both fuel types. I will happily have any solution so long as the manufacturer has sorted the car as a package. Cracking engine and bad chassis- no thanks. Wooden brakes and floppy steering would ruin a car with the most incredible engine.

I think turbo engines will dominate the future as the best compromise for road cars of performance and economy.

For a track weapon I would fancy an naturally aspirated engine and something nice and light.

[i]I find the response of a turbo diesel acceptable. It strikes me as unreasonable to expect a 1.9 Golf to go like an eXup, so I can't really understand your point.[/i]

The point is that a decent non-turbo car (for example; either of my last two, a 3.5i V8 or 3.0i V6) is far nicer to drive than pretty much any smaller engine turbo with the same bhp - especially when going from non-turbo petrol to a turbo diesel.

And, that a decent motorcycle really makes you appreciate non-turbo engines, for their ability to just rev from any point, with no lag.

My wife's 1.9 turbo diesel golf has one helluva crisper response than my normally aspirated diesel 3 litre Merc. But then it weighs half what the Merc does. Think there's more to it than just the turbo, as garage-dweller says...

Well I'm sure that something like a 6.2l AMG is almost the perfect performance engine (c63 please) however given purchase, fuel and tax prices that isn't going to happen for many. Combining a combo of fuel efficiency, little lag and high torque a big modern tdi is a good alternative. Pretty good response and performance from most normal driving situations?

I mull over this very same issue every time I fire up the mighty Mondeo. 🙂

There's no such thing as a "better" engine, people like different things- I love the surfing, effortless feel of a decent sized turbodiesel, I rode v-twin bikes for the same reason.

' there's no substitute for cubic inches ' 😉

No replacement for displacement!

Usually said by F150 drivers I know 🙂

Merchant ships have electric auxiliary blowers in their diesel engines for low speed running when the turbos won't be operating.

http://www.sae.org/mags/aei/11244

I've not driven any turbo engine that gives the same crisp throttle control of a good normally aspirated engine.

Nice, instant throttle response up to about 3500rpm, then over the next 1000-1500rpm your available power roughly doubles. There's nothing quite like it. And none of the lack of torque nonsense. If we're talking throttle response, that doesn't include driving everywhere in 6th gear and still expecting effortless overtakes.

I've got an old Transit sat outside with a variable nozzle turbo and even though it's got 220,000 miles on it, it still impresses me with how little lag it has!

I must admit to not having a vast experience of different cars but I do like the way my old 16v KR GTI got more and more urgent as the revs increased. But I can't ignore 225 (stock) BHP, so the S3 BAM lump is on its way.
As I get older easy overtaking starts to appeal, but they do sound a bit pants compared to a revvy NA. That said my mate's 4.2L XK seemed to be the best of both worlds, given that I wasn't buying the petrol 🙂

Triple scroll concentric turbo chargers are in a completely different league to most conventional and even variable vane turbochargers. Sadly even these tend to run out of puff toward the top end of the measly rev range.

I went from 1.0 Nissan Micra with 61bhp and about 110nm of torque to a 2.2TD Toyota Avensis with 180bhp and 400nm. I enjoyed driving the Micra fast more than I do driving the Avensis fast even though the diesel can leave quite a lot of other cars on the road in a cloud of soot.

I think in my case it's a lot to do with being able to extract the most from a car and still stay (reasonably) within the law whereas in the faster car it's much harder to have a bit of fun as at slower speeds it's just not that involving. Mind you, that could be something to do with it being a Toyota Avensis.

I'm sorry, is this a thread about cars, or a game of top trumps?

My Tornado GR4, well basically the engine is one bloody big turbocharger and it'll reach a ceiling of 50,000ft in about 3 minutes.

Can you get a bike in the back?

@tthew Your Tornado is bloody slow... A Lightning would get to 58000 ft in one minute. See ya! Do try to keep up...

Can't we just assume that if you can think of any conceivable way of extracting power from an engine that

a) the Germans have either done it/are on with it - and will do a bloody good job of it

b) the Japs have either tried it/will copy it/have some batshit crazy alternative with varying results

c) the Yanks just thought **** it and increased the displacement?

Rather than wasting all the brains on developing technology for a fuel that will run out as it is a finite resource, why not spend it making something sustainable, and then just for a change the manufacturers actually make all items serviceable, so if something needs a 5p washer/rubber widget that can be changed rather than having to junk a £100+ assembly.

A GR4 getting to 50000?! In three minutes?! Good gag!

Lol! I used to have to reduce my climb speed so the F3 could hang on to my wing and that had engines 'optimised' for high level...

Pitched thrust vectoring turbofans.

*waves*

[IMG] [/IMG]

Pretty pointless generalising with stuff like this as there are such a vast array of types, tunes, motors etc that even if you compare one turbo'd motor to another the difference will be dramatic.

If you drive a car with a Rotrex type SC it will feel a LOT different that a car with a twin scroll roots type SC.
Likewise a variable vein turbo will feel very different than a bog standard turbo.

Add to that different engine sizes, cylinders, tunes etc and it makes a MASSIVE difference.
A roots SC feels totally different on a 5L V8 than it does to a 1.8 4 cylinder in-line 4

Jump in a E46 M3 and it'll feel dramatically different than a Civic type R.

Right now i've got one of each (Smart for2 = turbo, MX5 = MP62 roots SC, A3 = N/A 3.2L V6) all the cars each serve a purpose and they all offer varying degrees of driving entertainment.

I think modern electric steering and auto gearboxes is more a concern when it comes to our future driving enjoyment than what type of method a motor uses to make it's power.

Tough to see into the future but it's a good time to start up a turbo rebuild company 😉

Turbo chargers = good power, good economy, driving experience compromised through lag

I have a Golf GTI, it has no noticeable turbo lag whatsoever. It feels normally aspirated. It's not like an old Saab turbo!

New cars mostly use small spinny turbos that make lag pretty much a thing of the past. The old whopping great turbos that were all or nothing are thankfully gone.

Revs.
That's all you need, if not fastest, it's most fun.
eg bikes, or better still, bike engines in kit cars.

I think Chrysler developed a hybrid turbo/supercharger thing a few decades ago.
It would be powered like a supercharger at the low end and then a clutch would disengage at higer revs so it would work like a normal turbo. I guess it wasn't embraced by the merkin market and quietly shelved, like their big V's that could shut down various cylinders in cruise mode (basically used them as air springs so were apparently quite an efficient trick).

There are advantages to turbo in terms of driveability. My mate's Skoda 1.8t petrol has a flat torque curve from 1,800rpm, that's only possible because of its turbo. Pulls like a train from low diesel type revs, 1,800rpm and keeps piling on the power until 6,000rpm. Nice.

A simpler solution to the OP's 'problem' would be an electric hybrid system. Store energy in a battery and dump it to the wheels whilst your NA engine is winding up. If anyone thinks hybrid tech is only for wussy eco cars, have a look at Lexus.. GS450h

Need a supercharger, turbo charger, etc?

Engine's too small.... 🙂

Gonna start a new thread. "What bike rack/canopy bars for a Tornado GR4?" Needs to stay on at full thrust. 😀

Or another idea to eliminate lag - a compressed air cylinder to ram air into the intake for half a second til you're on boost.