E46CT

Car and Driver's instrumented test for the IS200t and GS200t differ wildly.

Here's what they tested for the GS200t
C/D TEST RESULTS:
Zero to 60 mph: 6.6 sec
Zero to 100 mph: 16.7 sec
Zero to 130 mph: 34.0 sec
Rolling start, 5-60 mph: 7.5 sec
Top gear, 30-50 mph: 4.0 sec
Top gear, 50-70 mph: 4.9 sec
Standing ¼-mile: 14.9 sec @ 95 mph
Top speed (governor limited): 143 mph

And here's the IS200t
C/D TEST RESULTS:
Zero to 60 mph: 6.8 sec
Zero to 100 mph: 19.3 sec
Zero to 130 mph: 41.3 sec
Rolling start, 5-60 mph: 8.0 sec
Top gear, 30-50 mph: 4.4 sec
Top gear, 50-70 mph: 5.1 sec
Standing ¼-mile: 15.3 sec @ 91 mph
Top speed (mfr's est): 143 mph

CLEARLY, the GS200t posts superior numbers, beyond any reasonable or even significant margin of error. And don't forget the GS is about 200 lbs HEAVIER.

and just for fun, BMW 528i 2.0 Turbo numbers:
C/D TEST RESULTS:
Zero to 60 mph: 5.9 sec
Zero to 100 mph: 15.9 sec
Zero to 130 mph: 31.6 sec
Rolling start, 5-60 mph: 6.8 sec
¼-mile: 14.5 sec @ 96 mph
Top speed (governor limited, mfr's claim): 150 mph


We all know it's apparent Lexus intentionally handicapped the IS200t when compared with other manufacturer powerplants of the same caliber--such as BMW's 2.0T. With all the specs, turbo size, horsepower, etc being nearly identical, the BMW clearly outclasses the IS Turbo in performance. So it's apparent (to me anyway) that this is just software trickery so the overall performance in this highly competitive segment shows a bigger gap between the IS200t and IS350.

So why is the Lexus GS200t, despite having the same exact powertrain, MUCH faster? I suspect there's a "Secret" tune Lexus has for the GS200t. Imagine if you could upload that tune to the IS? What do you all think of that, particularly the IS Turbo Tune crowd? It seems too looking at the 528 numbers that the heavier GS would fall flat on its heels with the IS200t tune when compared with German rivals. Clearly the GS Turbo is still slower than the 528i but a LOT closer than the IS is to the 328i. Interesting.

The 0-130 MPH time is the biggest shocker. That is a MASSIVE gap to reach 130mph. 7 seconds?

EXE46

Very interesting observation there, Lexus screwed us with this motor intentionally just to avoid having similar performance to the IS350.

DaveGS4

iTrader: (2)

Sheddy

I am thinking the same. Their results are way off.

loophole35

Same drive too? Also I have driven both and the GS does seem to have a little better throttle response than the IS.

Sheddy

These are their 2017 IS200t results-

C/D TEST RESULTS:
Zero to 60 mph: 6.5 sec
Zero to 100 mph: 17.3 sec
Zero to 130 mph: 35.6 sec
Rolling start, 5-60 mph: 7.6 sec
Top gear, 30-50 mph: 4.0 sec
Top gear, 50-70 mph: 4.9 sec
Standing ¼-mile: 15.0 sec @ 94 mph
Top speed (governor limited): 139 mph
Braking, 70-0 mph: 170 ft
Roadholding, 300-ft-dia skidpad: 0.88 g

If you download their test sheet they brake torque and release at around 2200rpm. The weather is listed as-
GS200t "WB 45 DB 51"
IS200t "WB 62 DB 70"

Wet bulb and dry bulb thermometer readings?

E46CT

Yep temp would obviously be considered a factor but I'm not sure any temp would account for a 7 second difference to 130 mph. Also AFAIK turbo engines are especially designed to hit a particular power or boost target when under various conditions so that similar power is made no matter what. Someone correct me if I am wrong on that. In other words an IS or GS turbo should theoretically perform the same whether 40 degrees or 100. I notice my boost doesn't reach as high when cold out. Could be all in my head though.

Finding out the truth will come down to viewing the software tables of both tunes and/or comparing software/firmware revision #s. Anyone have access to that here? Would love to find out.

E46CT

interesting that they brake torqued. i always hoped they had done that for these tests. maybe they didn't for the IS200T test or didn't fully boost? Cause there's no way of reading boost when brake torquing so theoretically you could brake torque but not reach full boost if you don't wait long enough

E46CT

According to C&D, they account for weather differences in final posted times. Interesting.

"Before testing any vehicle, we fill it with gas, check the fluids, and set the tires to the manufacturers' recommended pressures for light-load, high-speed running, if they are specified. Then we weigh it. At the test site we measure humidity, barometric pressure, and temperature. To eliminate the effects of weather on performance, we employ proprietary empirical correction factors to adjust all results to dry air at 14.7 psi and 60 degrees Fahrenheit using PsyCalc 98 software (www.linric.com) to crunch the weather data. Since cars run best in cold dense air, our correction tends to add time to results generated in low-temperature, high-pressure conditions and subtract time from hot-weather, low-pressure tests. To cancel the effects of the wind, all acceleration tests are run in both directions; the best runs in each direction are then averaged."

Sheddy

"Temperature and air density

As air temperature increases, the density of the air, and the amount of oxygen it holds decreases. This means that the turbocharger has to work harder, spin faster and compress more air to produce the same amount of boost it would at lower temperatures.
As the temperatures inside the turbocharger gets higher, the turbocharger can no longer increase it’s speed efficiently, meaning that knock on effect of this is that engine performance, acceleration and top speed are also reduced.
In addition, hotter air also has a secondary affect on the turbocharger, by naturally increasing the operating temperature inside the turbo. Usually, the intercooler works to cool the air from the hot air intake, but in warmer temperatures, the intercooler becomes less efficient, as it is also exposed to the warmer temperatures.
Again, this serves to increase the amount of work the turbo has to do, reducing the overall efficiency and performance of your vehicle’s engine."

I am a believer that the IS200t ECU has factory set limitations that needs to be bypassed to make more power.