New Turbo Cars

[Smurf]

Hi all,

As you would have probably noticed, turbo sports cars are now producing amazing torque figures at very low revs such as 2k to 2.5k in the rev range. From what I can tell they feel similar around town to large capacity engines. As I get older, this facet has become more desirable than a crazy top end.

A couple of questions:

1. What are they now doing to get the torque so early in the rev rance. Is it direct injection?

2. Do they sacrifice power for the torque?

Also, is there anyway of improving the drivability of my R33 GTS25T around town. Only mods are exhaust and pod filter however as you would all know it doesn't feel all that strong until maybe 4k revs.

Cheers

Will

Edited July 5, 2007 by Smurf

[Basti]

this helps quite a bit with your drivability with a stockish r33. http://www.skylinesaustralia.com/forums/in...showtopic=42895

[scathing]

What are they now doing to get the torque so early in the rev rance. Is it direct injection?

Turbo selection, compression ratio, and good tuning.

Since OEMs don't design with the aftermarket in mind, they put in parts to suit their aims (which is drivability). As such, they'll run engines with smaller turbos that match the engine's flow characteristics (for faster spooling), low boost and small intercoolers to keep the response up, and high compression ratios inside the engine to make it as efficient as possible. Better modern fuels and ECUs, along with a conscious decision to run a low boost / high compression engine, are probably where the biggest "gains" are found.

The exhausts etc are pretty efficient as well (my mate's just gotten a Polo GTi, and apparently an aftermarket catback is only worth 5fwkW, which is sweet FA).

[Forged]

A couple of questions:

1. What are they now doing to get the torque so early in the rev rance. Is it direct injection?

2. Do they sacrifice power for the torque?

Relatively small turbo + high compression + direct injection = lag free response, strong mid range and still acceptable top end. Two great examples of such modern turbo engine, the BMW's 3.0 l6 twin turbo and AUDI/VAG 2.0FSIT direct injection turbo l4.

Sacrificing power for torque? For a road car torque is obviously more important, torque = drivability. In fact you should consider the other way around, why would you want to sacrifice drivability for a mere extra few kw up the top end?

[Duncan]

try the link basti posted before you get too worried

[RB30-POWER]

Below are some things that are different today as compared with turbo cars of say late 80’s, early 90’s

Higher static compression ratios

Intercooling

Better multivalve cylinder heads (increases Volumetric efficiency and increased knock resistance - better squish zones, relates to above)

Higher octane fuel.

Double overhead cams

Continuously variable cam timing over infinite range

Ceramic turbos

Variable geometry turbos (will see heaps more of these soon)

Direct injection

Light weight oils

Low friction technology in alot of engines

Advanced knock control now days

Improved ECU processing power

Sequential injection

Higher engine operating temps for increased efficiency

Ecu controlled alternators

More efficient drive trains, less friction loss.

[MBS206]

My R33 is really kicking me hard in the pants at 2500RPM and it's running FMIC, 3" turbo back exhaust, and a lightened flywheel.

Compared to a mates old one, (Stock R33) mine seem to roll out of corners on less throttle quicker then his would. Putting it down to the flywheel.

Oh, and 10PSi of boost. But I'm talking about still being in vacuum response out of corners.

Even when just lightly cruising in vacuum I can feel the turbo hitting efficiency from 2500RPM and I'm having to ease the throttle off to stop the car taking off up the road.

[joeyjoejoejuniorshabadoo]

is it a full exhaust or just cat back...

with cat back my full boost (.8bar) hit at 3500ish, with turbo back 2700ish

[r32-25t]

rb30 power

we wont see Variable geometry turbos on anything petrol, expcept in a prosche

because porsche have patend their design unfortunatly

brett