Turbo vs NA

bobbarley · 26 Sep 2011 at 18:33

Love turbo's you can't beat that oomph when it gets onto the boost, and the sound is amazing

Plus you can re-map for tonnes of extra power at very little cost.

Begbie · 26 Sep 2011 at 18:34

Zefan said:
From the few cars I've driven I prefer a turbo. I'm comparing petrol N/A to diesel turbo here

My Brother in law's 2.0 petrol Mondeo felt really weird compared to my 1.8 TDCI Focus. I think I'm just used to having the power in a specific spot, it felt like I could never find the power in the petrol.

There isn't much power tbf, and your doing it wrong

khevolution · 26 Sep 2011 at 18:36

Kenai said:
No they're not.

From Garrett:

What is Turbo Lag?
Turbo lag is the time delay of boost response after the throttle is opened when operating above the boost threshold engine speed. Turbo lag is determined by many factors, including turbo size relative to engine size, the state of tuning of the engine, the inertia of the turbo's rotating group, turbine efficiency, intake plumbing losses, exhaust backpressure, etc.

What is Boost Threshold?
Boost threshold is the engine speed at which there is sufficient exhaust gas flow to generate positive manifold pressure, or boost.

http://www.turbobygarrett.com/turbobygarrett/tech_center/faqs.html#t3

An example of this would be a slowish gearchange - the exhaust flow would drop off as you let off the accelerator, the turbo would begin to slow down and then when you reapplied the power after you gearchange, you would notice a small hesitation while the turbo spins back up to full speed. In some cars this will be pretty much imperceptible but in other cars may be quite noticeable.

you learn something new everyday

Minstadave · 26 Sep 2011 at 18:37

bobbarley said:
Love turbo's you can't beat that oomph when it gets onto the boost, and the sound is amazing

Plus you can re-map for tonnes of extra power at very little cost.

Tuning is a definite plus point for Turbo cars, at the cost of expensive bills when it goes wrong.

Liampope · 26 Sep 2011 at 18:38

Meridian said:
Do people mean real, technically correct "lag", or are they using the word in the Top Gear sense (trying to boot it in the wrong gear)? Because few turbo cars these days have actual, genuine, lag.

M

Couldn't agree more. Reminds me of some retarded TV spot, probably Top Gear, on something like an XJ220 where they basically booted it in top gear at about 1000 rpm and thought the fact they didn't start going anywhere till a while later was turbo lag. No, you morons, you were in the wrong gear*.

* although I think the 220 did famously suffer from bad turbo lag. But did it reeeeally

Davefran · 26 Sep 2011 at 18:46

Clarkey said:
boost ***, never had an issue with lag on a petrol turbo, even running up to 350hp on a 2.0l 4pot is responsive enough. Turbo diesels on the other hand, oh dear. Lag city with absolutely no guts at all off boost, makes for an irritating drive. Why doesn't anyone make a supercharged diesel?

If you're driving correctly, i.e in the right gear, it's near impossible to get caught out by turbo lag.

Kenai · 26 Sep 2011 at 18:52

Davefran said:
If you're driving correctly, i.e in the right gear, it's near impossible to get caught out by turbo lag.

Turbo lag has nothing to do with what gear you're in, you're confusing it with boost threshold.

Lag (to give another example) would be noticeable if you were in third gear, accelerated to 5000rpm but let off as someone pulled out in front of you. Assume you stay rolling in third gear with no throttle being applied, they then move back over and you plant your foot to floor from 4500rpm.

Turbo lag would be the short time delay the turbo takes to spin back up to full speed once the throttle was reapplied, even though at these sort of rpms you are well above the boost threshold.

On a small or efficiently designed turbo with very little friction or mass, this will be incredibly short and probably not even noticeable but on an old monster of a turbo that's heavy and not as well made as a modern turbo, this would give a very noticeable delay to the boost being reapplied.

naefeart · 26 Sep 2011 at 18:53

I don't care as long as it suits the car and my driving style.

I like the idea of a V8 with a supercharger or twin turbos.

For some reason I'm not keen on the idea of triple turbos, my OCD kicks in.

Muncher · 26 Sep 2011 at 18:58

NA is always my favourite but supercharged is very close behind.

Dr Who · 26 Sep 2011 at 19:01

I don't give a **** what it is, a turbo can be good and bad, so can superchargers, so can N/A.

Turbo and VTEC give the nicest shove in the back, for effortless driving, NA V8 or similar, for fast driving I love keeping a turbo on boost or vtec on the cam.

Clarkey · 26 Sep 2011 at 19:03

Davefran said:
If you're driving correctly, i.e in the right gear, it's near impossible to get caught out by turbo lag.

Unless it's a hateful diesel. I've not driven a fancy 6pot diesel so i'll reserve judgement on those but have used most of the different 4pot offerings and they are all the same. Bellow 2000rpm (ie all urban driving) it feels like the engine isn't even on, and when around or above the threshold the throttle is still unresponsive requiring a large opening to get any boost which is vital for any kind of acceleration.

Sin_Chase · 26 Sep 2011 at 19:04

NA for sharpness and power delivery. Assuming I could have the same power as other cars I would always pick NA.

Unfortunately large power in NA is very expensive or impractical, if I take the FI route my first port of call will be SCed.

khevolution · 26 Sep 2011 at 19:07

I wouldn't mind trying a decent supercharged rwd car on a decent empty road, sounds like a perfect day to me

Hades · 26 Sep 2011 at 19:09

I love a nice big NA for the instant response. Then for an ideal world a nice supercharger on top.

Dr House · 26 Sep 2011 at 19:11

I have never owned a NA fast car so I can't really comment but I have had a few fast turbo's.

I like them because you can get a lot of extra power out of them with a simple remap but still get reasonable fuel consumption on a long motorway run.

-Neil- · 26 Sep 2011 at 19:12

Supercharged or N/A for me, lovely throttle response.
A well mapped SC is awesome, loads of revs with torque everywhere

Neil.

Fuzz · 26 Sep 2011 at 19:13

I will be the first to admit there is something about proper handfuls of

BOOOOOOOOOOOOOOOOOOOOOOOOST

in a turbo car.
However trying to drive a turbo car fast on a twisty circuit is nowhere near as much fun as pedalling some crisp NASP engine around on throttle bodies barking at you to go faster.

NASP for me I'm afraid and I'm well versed in both.

mattyfez · 26 Sep 2011 at 19:19

N/A with progressive nitro.

GT3 · 26 Sep 2011 at 19:24

N/A car with low down torque, peaky engines even with a very close box get a bit tiring to drive unless flat out constantly.

Love my Xsara VTS engine, but needs a shorter box. 1st few gears could do with being a bit closer. Hate my revvy MR2 N/A and my old 106 1.3 rallye wasn't as fun as everyone makes out.

Haven't owned a great number of petrol turbo cars but the 406 SRI I had over winter got me wasting loads of petrol as the boost was a bit addictive!

hillbilly2 · 26 Sep 2011 at 19:25

Clarkey said:
boost ***, never had an issue with lag on a petrol turbo, even running up to 350hp on a 2.0l 4pot is responsive enough. Turbo diesels on the other hand, oh dear. Lag city with absolutely no guts at all off boost, makes for an irritating drive. Why doesn't anyone make a supercharged diesel?

The Mazda Capellia(Mk 4) had a supercharded diesel option.I used to work with a guy in NZ that owned one,rare as rocking horse ****.

http://en.wikipedia.org/wiki/Mazda_Capella

http://www.modified.com/editors/0705_sccp_comprex_compressor_supercharger/index.html

I think Ferrari tryed the "Pressure Wave Supercharger" on F1 cars on the 80/90's ?