Leigh2

I was at Miller a couple of weeks ago and Patrick Long was there driving the outer loop in (probably) the same 2RS and 3RS. Didn't time the laps personally but heard 2:02 in the 2 and 2:05 in the 3.
Crummy camera and worse photographer but you get the idea

savyboy

There you go, they say a picture is worth a thousand words...

iLLM3

Interesting to hear about this so called "lag" .... You guy's have to see this car rev/rev it in person yourself. The tach FLIES, almost NA like, so to me this is BS having driven both... Obviously it's not as quick revving as the GT3 RS, but in no way shape or form can the GT2 RS be considered "laggy"...

Carrera GT

I haven't driven the 2RS, but I've been a passenger -- it's got noticeable lag. By turbo standards, it's impressive off-boost and the transition/onset is quick, by turbo standards. If you're used to a 450 hp 3.8 RS, where your foot is connected to a linear stream of power that reaches 2000 rpm past the rev-limiter of the 2RS, then you notice the lag. I wouldn't consider it much of a criticism, it's just there as part of describing the whole show.

TRAKCAR

Sometimes I like lag, it builds the anticipation....

ATL Fahrer

...just depends on where in the turn you're doing the anticipating

Z06

With said new VTG and single mass flywheel the RS will boost quicker then most turbos... at the track I never loose boost, I can do my braking then roll on the throttle and there is always massive power waitng!

In this GT2RS videos there was no lag...I don't get this talk about lag at the track?

Carrera GT

What you're describing is lag -- it's the transition from a state of little or no boost (or even a condition of vacuum) to a state of sufficient throttle response or even full boost if the demand from the throttle is maximum ergs.

The GT2 RS has a noticeable delay in building full boost. It's quick (and as I mentioned, by any turbo standard, it's a quick onset) but it's still there.

With practice, a driver can work around lag (from the throttle cycling of the early F1 turbo era, to left-foot braking and now modern day electronics, shortened intake paths and variable cold side veins) but the lag is there in this car just as with any previous turbos.

I still enjoy driving a 993 Turbo with a GT2 engine (K28's, larger intercooler) so I enjoy driving around lag and I think the ultimate power justifies the compromise on throttle response.

Porsche has reached that point of incremental returns on very large investments in improving their turbo engines, that we have to assume we've reached a plateau. Until there's a significant reduction in component weight and complexity (to afford the introduction of a secondary mechanism to keep the intake manifold pressure, while allowing the engine to behave in an "off boost" manner when the throttle is trailing or closed) then we have to accept some lag as the inevitable physics of compressing the volume of the intake between the compressor wheels and the intake valves.

It's great to have higher static compression ratios, smart electronics, faster, lighter turbos, even direct injection and larger displacement help to fill the lag with off-boost power, but it's still a matter of the fuel-air mixture being charged by turbos that reside some physical distance away from the combustion chamber. Even if we went to individual turbos mated to individual throttle bodies, there's still be some lag (and a lot more complexity and weight.)

With fuel efficiency, emissions and noise all being more important than throttle response and drivability and race-winning engine characteristics (after all, Porsche is retiring their thoroughbred race engine in favor of a simpler street engine that's cheaper to build with fewer components) we have to expect to see turbos in future Porsches. If anything, I'd rather see some lag in lighter, faster revving engines than the move to larger displacement engines that run lean on superchargers to make their emissions and efficiency cycles -- the big Benz engines sound great, but they're boring engines to drive.

Here's hoping Porsche has learned some tricks that it can carry over from the 4.0 RS engine that will let it continue to compete with a flat six and not resort to falling into "me too" and building V8's to compete with McLaren (already turbo'd) and Ferrari (surely not too far away from forced induction in some of their vehicles.)

TrackDays247.com

Yes, they (t-charged) will all have lag - even a little.
My car has 514HP and has just a bit of lag, but it has to be above 3.200 rpm.
At that point hang on to your *******.

savyboy

No load revving has nothing to do with turbo lag. The lag will be most noticible when you are off by a gear or in the lower rpm ranges with the engine under a load, for example applying power out of an apex or especially an uphill apex.

I have experienced this personally in my car at both Thunderhill and Laguna Seca, tracks I have run many times before in my 3RS. The 2RS demands very different throttle management to achieve good corner exit speeds.

No doubt the 2RS has very quick spool-up compared to just about any other turbo motor, I fully agree this is true, but as noted below, all turbo motors by nature of design will have some lag. It's baked in the cake and not possible to eliminate.

Without a brake and throttle graph mapped to location on track you cannot see or hear the lag, it's in the butt sensor. You would notice it is necessary to apply throttle far earlier at a given point on track versus a NA engine in order to get the turbos spooled and rocket you out of a turn.

There are some corners where I am still trail braking towards the apex and yet need to get the on the gas to spool the turbos and it requires some head scratching and change in corner entry to drive around this.


What he said

stout

No question, the GT2 RS has some lag. That said, it's on the better end of the big lag-"no lag" continuum.

Compared to a 3.0-liter 930, I could see where someone might say the GT2 RS has "no lag." Compared to a GT3, well, there is a definite pause before your throttle input is translated into increased forward motion. But you can anticipate turbo lag, and thus drive around it. As you get to know the car, it becomes subconscious, much like using a clutch or heel-toeing does after a while.

FWIW, as much as I love CGTs and GT3s — and high-butterfly 3.0s etc. —*for their incredible throttle response and overall revvy-ness, I love driving good turbo cars just as much. It's why one particular turbo car remains in my top two.

I guess I find the subliminal challenge of figuring out when turbo boost will enter the picture against rpm and load an interesting element. And the payoff, as Craig notes above, is something that normally aspirated cars — especially 911s — simply cannot duplicate.

In my experience, it seems people either like turbo cars or they don't. Or maybe it's that they're either open-minded about turbo cars or are they aren't? Or maybe it's that they just haven't had a good drive in a good one?

For me, turbocharging is just another curve ball. Like a rear-engined car, it can be set up well, used well, and advantageous.

pete

9972RS

so how do we explain the japanese being able to reduce the lag significantly. I've only driven the GTR and the lag was minimal

savyboy

Fully agreed. Well said. You should be a writer!





A 2RS is a lot of fun on track and additional challenge for a driver open to it, exactly as Pete says.

amaist

It's still there.

Displacement helps. 3.8l is not a small motor with decent torque due to size.

Have you driven the GT2RS? I would estimate similar lag levels with slight advantage to the GTR. Definitely not like in a 2.0l high boost motor.

BTW the GTR has less horsepower compared to the GT2RS. I.E. less boost -> less lag.

BMW puts turbos on almost everything now. But you don't feel lag because the turbos are small and boost is low. They are there for efficiency more than for power. We will see how the new M cars will handle that. I suspect not much lag due to huge motors. The M5 will have something like 5.0l.

savyboy

Good points. Also: People forget, the GT2RS is a 3.6 motor not 3.8.