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However, don't forget that the presence of Dynamic Rear Steer (DRS) in the GS F-Sport tested by Motortrend. Rear Steer in essence works by reducing the effective wheelbase/length of the vehicle as it turns around a corner. That is one reason (other than the superior suspension of the 4GS as compared to the 2IS) why the 4GS behaves like a smaller car and is faster than the IS350 on the handling circuit. So simply comparing physical wheel-bases/lengths may be misleading.
Secondly, if you watch this website where Motortrend and Automobile magazines conduct their testing, they apparently use Vbox testing which seems to mitigate human error :
Other than that, you won't get any arguments from me about the nose-heaviness of a V8 spoiling the handling of a car. Weight in the nose is never good.
Mass
In physics, Centrifugal Force around a circle = (mass x velocity squared) divided by the radius of the turn.
Therefore, for any given radius of curvature, as the mass of the motor vehicle increases, the velocity decreases, but because the velocity is squared, the velocity must decrease significantly!
Thus, weight or mass, is the bane of motoring.
The number one detraction for the IS350 versus GS350 F Sport dynamic comparison is the F Sport's additional 100 kg extra weight. About 220 pounds.
Polar Moment of Inertia
Have you ever watched an ice skater spin?
When they spread their arms and legs out, they only spin slowly.
However, when the clasp their arms together and cross their legs, they spin very very quickly.
So too with the motor car.
Short cars like the IS250 and IS350 change directions very quickly; long cars like the GS350 F Sport slowly - a quick test drive will prove.
Natnut, have you ever had a chance to test drive one of those old 1999-2006 IS200 2.0 in-line sixes? It's one of the most agile sedans around. More agile than a BMW 3 Series.
Active Parallel Rear Wheel Steering?
Yes, you're right, the latest 4GS does have active parallel rear wheel steering for up to something like 1.5 degrees of parallel rear wheel movement to enhance rear end stability at high speeds, and under torque.
The standard IS and standard 4GS does have passive rear wheel steering via deformable suspension bushings, for only 0.5 or 1.0 degrees of passive rear wheel steering.
Unfortunately, the active parallel rear wheel steering unit, is only a minor player, and only plays a small role in total cornering performance of a motor vehicle.
It just isn't enough to compensate for the GS 100 kg extra weight, and 1 foot extra overall length.
One could also speculate, that if the next generation IS350 due in 2013 has active rear wheel steering as well, then the IS will always out-handle the GS, model for model; its a size/weight compromise.
Active Opposite Rear Wheel Steering
Note that the active rear wheel steering, can also steer in the opposite direction, to decrease the turning circle at low speeds.
However, in this case the rear wheels only steer some 5 degrees. Not much hey?
Meanwhile the front wheels steer a significant 30 degrees.
Some people ask why?
Because when the front wheels steer, the nose turns in.
However, when the rear wheels steer, the tail swings wide.
The problem is that we humans have no eyes behind our heads, therefore we can't see when the tail end is swinging wide.
Thus, rear wheel opposite steering to reduce the turning circle, is only limited to some 5 degrees of steering - so we only get a small reduction in the turning circle, but not a huge reduction.
This opposite direction steering, to reduce the turning circle, has no effect on motor vehicle dynamics.
Mind you, it is unlikely that the next generation IS will get active rear wheel steer.
It is also unlikely that the next gen IS will get the GS's lightweight aluminium bonnet either, for that matter.
GS F Sports Faster than IS350 Data?
Unfortunately, this data was measured on different days, under different conditions, so the data is not comparable.
In actual fact, if you test drive the IS350 against the GS350 F Sport, back to back, you'll find the IS350 much more agile than the F Sport.
Weather
Yes, it looks like indeed Motortrend does use sophisticated dynamic measuring equipment.
The next most important factor are the test conditions, ie the weather.
For data of the IS350 and GS350 F Sport to be truly comparable, we must test both vehicles on the same day.
The data of the IS350 and GS350 F Sport was unfortunately collected on different days.
Notice how these two IS-F's have significantly different figures:
From Motortrend :
2012 ISF
weight 3778lbs 0-60 4.5s 1/4mile 12.9s@111.4mph 60-0 105ft skidpad 0.96g slalom 24.8s@0.79g
Compared to
2008 ISF
weight 3805lbs 0-60 4.3s 1/4mile 12.7s@113.4mph 60-0 108ft skidpad 0.91g slalom 25.1s@0.77g
If two of the same IS-F's have data this different, then just imagine the discrepancy in data between two different vehicles like the IS350 and the GS350 F Sport?
Weather plays an important role in performance.
Note how in winter or the cooler months, you get better mileage than in summer?
That's because the air is cooler, colder, and denser, hence more volumous; ie more molecules of air in the chemical reaction.
More molecules of air and fuel leads to more kilojoules of energy release from a single chemical reaction.
Performance depends on air temperature, air pressure, and humidity levels.
What we could do, is ask Motortrend to test both the IS350 and GS350 F Sport back to back, on the same day for us.
Alternatively, you could test drive the IS350 with a GS350 F Sport yourself, back to back, on the same day, and the difference in handling between the two vehicles is like night and day.
Unfortunately, dynamics is largely dependent on weight, so the hi tech active parallel rear wheel steering of the F Sport is only of small benefit to tail end stability, such that it just can't compensate for the extra 100+ kg extra mass of the F Sport.
Touring Cars
That's why in Group A Touring Car Racing, compact sedans like the 3 Series, C Class, and A4 are chosen for Touring Car racing, rather than the much heavier and longer length to width ratio 5 Series, E Class and A6.
Mass is the bane of motoring.
The extra mass not only blunts the linear and angular acceleration, the mass also has adverse effects on tire wear, and brake pad wear.
And more pit stops to refuel too.
Theoretically, if Lexus really wanted to set the midsize market on fire, they could come up with an aluminium 5GS, or even a carbon fibre 5GS.
The greater length to width ratios of the larger cars, are more dynamically unfavourable too.
To maximise dynamics, we want a more relatively short, but wide foot print, similar to an Formula 1 car, or a Lamborghini...
So you're saying different weather conditions led to the GS350 F-Sport to be 1.5 seconds faster than the IS350 on the slalom?
That the 2nd Gen IS350 is faster in real life but somehow random differences in weather and drivers allowed the GS350 F-Sport to not only catch up to the IS350's times but somehow surpass it by 1.5 seconds?
Sorry, I'm not buying that. Besides, I've already posted a recent test where the IS250 F-Sport (that you claim is a superior handler to the IS350) still posted slower times to the GS F-Sport.
I don't get why you have a hard time believing that a newer chassis (4GS), despite being larger and heavier, could have improved suspension tuning to a level such that it can outhandle a lighter but older chassis( 2IS).
Fact is, the 4GS chassis outhandles the even newer BMW F30 (new 3 series) chassis. So believing that it could outhandle an older chassis like the 2IS isn't too much of a stretch.
It's simple.
When we test drive, we believe.
Natnut, have you actually driven an IS350 and a GS350 F Sport back to back at all?
You must test drive them.
The difference in agility is great.
The GS's aluminium bonnet and active rear steer is great, but it cannot compensate for the extra 220 odd pounds.
Most importantly, you need to test drive them.
The smaller lighter IS is much more agile.
Any data, measured on different days, must be viewed with caution.
For data to be truly comparable, it's as simple as testing the cars back to back on the same day.
However, on different days, it cannot be compared with 100% certainty.
But test them back to back at your local dealership...
Right now the onus is on you to prove your assertion since you only have your "seat-of-the -pants" experience to back it up. I'm using objective numbers (published by a major car magazine using sophisticated testing methods) to back up my assertion that the GS F-Sport handles better than the 2IS.
Yes, the subjective results from a back to back test drive, is in this case obvious.
We only just tested the GS350 F Sport last weekend, for a long test drive.
I own a 2006 IS250, which I have passed onto my father.
Objectively, and quantitatively, unfortunately the results are not directly comparable when measured on different days, especially when the results are so close.
They are only directly comparable when measured back to back on the same day, especially when the results are so close.
The evidence is in your very own data below of the 2008 versus the 2012 IS-F:
Notice how the same car yields different data on different occasions?
You see how reliable/unreliable the data is???
You see the discrepancy?
Unfortunately, 0.91g versus 0.96g's is a significant difference.
However, apart from that, all the other information you and Motortrend provided is consistent.
The old 5 Series is more agile than the new bigger and heavier 5 Series.
Yes, the GS F Sport is more agile than the 535i M Sport.
Yes, the 535i M Sport is more agile than the 550i V8.
And yes, the IS-F V8 is a ripper in the straight, but is questionable in its agility.
And yes, the old 3 Series is more agile than the new bigger and heavier 3 Series.
And yes, active rear wheel steering helps, but only to a small degree.
Dynamics is still heavily dependent on weight, and the polar moment of inertia.
Weight is still the bane of motoring; ask any experienced performance driver.
That's why Group A Touring Cars tend to be based on compact sedans like the 3 Series etc, and rarely the bigger [nee longer] and heavier 5 Series.
From a physics point of view, another factor that you may also like to consider, is that once a heavy and large motor vehicle "yaws" and changes direction, its inertia wants it to continue to change direction, in other words continue to yaw in the same direction, but on a slalom you want to reverse the direction after every cone, hence the car fish tails.
Thus, it is the heavier and bigger cars that fish tail more.
Hence it is the heavier and bigger cars that require active parallel rear wheel steering more.
Natnut, if you business or holiday out my way, let me know, and you can borrow my IS for the whole weekend.
Alternatively, the most important thing to do is to test drive a local IS.
If you have a friend that owns the old 1999-2006 IS200/300, do test drive that one - it is a ripper for dynamics - the sedan equivalent of a Mazda MX-5.
Presently, there is a lot of positive journalism on the new 4GS.
However equally, there is still a lot of negative journalism going around too.
Never just take someone else's word for it.
Test drive the IS and the GS back to back at your local dealership.
Happy motoring...
Can I ask if you have actually driven the IS350 before Natnut? Back to back with a 4GS?
Let me know if you travel overseas much at all?
I would be more than willing to loan you my IS250 for a weekend if you venture overseas.
The IS350 is not only significantly lighter than the new 4GS350, but it is also considerably shorter in wheelbase and length.
The difference between the IS and 4GS in width is minimal, and in height is very minor.
When people ask why cars mainly differ in length, and not in width or height, its because we humans mainly differ in leg length and therefore height, as we get taller.
We differ little in width.
Because we sit inside a car, and the legs point forwards, cars mainly differ in length, and not in width or height.
That increase in width is actually for the 5th seat.
When we fellow humans sit next to each other, there is little difference in torso length, hence there is little difference in the height of the motor car.
Because the difference is mainly in weight, and in length, it affects the polar moment of inertia.
The greater the polar moment of inertia, the slower the "yaw", in other words, the slower the ability to change directions.
You will find that the IS250 changes direction much faster than the IS350, and that in turn much faster than the 4GS F Sport that I drove last weekend, especially if we compare the same IS F Sport version to a GS F Sport version.
The IS-F V8 versus the 4GS F Sport is a tougher and closer comparison, and the result depends; either could win.
Look at the degree of human error here.
It just goes to show how they are not exactly comparable.
Who is starting and stopping the stop watch? Human hands, or an electronic sensor???
So too, the Motortrend data for the IS350 is not accurate.
Even Lexus own data says that the IS350 does 0-60 mph in 5.6 versus the GS350's 5.7 seconds.
I have driven the IS350 about 12 months ago, and the nose isn't much heavier than the IS250.
The heavier GS almost matches the IS350 in linear acceleration.
However, model for model, the IS will still change direction faster than the GS, with more terminal grip than the GS.
The IS-F V8 has bags of linear acceleration, going from 0-60 in under 5 seconds, however when it comes to handling and breaking, the heavier V8 in the IS-F's nose works against it.
Here, the F Sport can actually superior.
I have never test driven the IS-F.
However the old 3GS in V8 handles terribly compared to the old 3GS in V6.
A nose heavy car will never handle as well as a nose light car.
When we test drive a Benz C250 2.0 Turbo against a C300 3.0 V6, the 4 cylinder version always has the lighter nose, the faster turn-in, and the higher terminal grip.
As for the Motortrend slalom, g-force, and braking distances, both the 4GS F Sport and IS-F must be measured on the same day for the data to be comparable.
And it also depends who presses the stop watch, human hands, or an electronic sensor?
The error in the human thumb and reaction times is considerable.
You are right.
The old smaller lighter 5 Series out-handles the bigger heavier current model.
And the F Sport seems to subjectively out-handle the 535i M Sport, according to our test drives...
lol...there is so much bull**** here I dont even know where to begin.
Very good, interesting discussion here, great points and data. Cannot deny the physics and I just love the support for the IS350. I have driven the GS 350 F-Sport on multiple occasions and agree that my IS350 just feels a bit more nimble, especially in traffic. But then, I am very experienced in my car and did not want to take many chances in the GS350 F-Sport. Racing aside, it's an awesome car. Lexus!
IS350 does feel much more agile, nimble and it does feel faster than GS350 Fsport at any speed....GS350 Fsport does give the driver much better feedback and overall connection than IS350.
GS350 Fsport is a great machine for it's size and handles really well...It is not meant to compete with its younger/smaller sibling with same powerplant.
That's like comparing 335i to 535i or S4 with A6 (Sports line).
So you're saying different weather conditions led to the GS350 F-Sport to be 1.5 seconds faster than the IS350 on the slalom?
That the 2nd Gen IS350 is faster in real life but somehow random differences in weather and drivers allowed the GS350 F-Sport to not only catch up to the IS350's times but somehow surpass it by 1.5 seconds?
Sorry, I'm not buying that. Besides, I've already posted a recent test where the IS250 F-Sport (that you claim is a superior handler to the IS350) still posted slower times to the GS F-Sport.
I don't get why you have a hard time believing that a newer chassis (4GS), despite being larger and heavier, could have improved suspension tuning to a level such that it can outhandle a lighter but older chassis( 2IS).
Fact is, the 4GS chassis outhandles the even newer BMW F30 (new 3 series) chassis. So believing that it could outhandle an older chassis like the 2IS isn't too much of a stretch.
Old thread bump. But i cant believe your thought process here. This is one of the most un informed threads on CL. I cant believe no one ever corrected you. Tsk tsk tsk.
Youtube search Is350 0-60 4.6 seconds.
Google search 2007 is350 13.5 1/4 mile.
The rwd 2006 to 2013 is350 with traction control disabled will do under 5 seconds 0-60. They will also do 1/4 in 13.4- to - 13.5. This is stock with street tires.
The 2is is faster than the gs350 of any year including fsport.
The 2is is faster than the new 8 speed is350 including fsport.
The 2is is faster than rc350 f sport or rc350.
Just because a cars newer doesn't mean its better. The 2006-2013 is350 is faster than any gs350. Any new is350 2014 up. And Any Rc350.
As far as handling who cares. The 2is on coil overs would be better than any gs350 or Rc350 on coilovers mostly due to weight. But consider the is f if you want a good handling lexus.
Also you picked the worse stats on the revised is f.
Old thread bump. But i cant believe your thought process here. This is one of the most un informed threads on CL. I cant believe no one ever corrected you. Tsk tsk tsk.
Youtube search Is350 0-60 4.6 seconds.
Google search 2007 is350 13.5 1/4 mile.
The rwd 2006 to 2013 is350 with traction control disabled will do under 5 seconds 0-60. They will also do 1/4 in 13.4- to - 13.5. This is stock with street tires.
The 2is is faster than the gs350 of any year including fsport.
The 2is is faster than the new 8 speed is350 including fsport.
The 2is is faster than rc350 f sport or rc350.
Just because a cars newer doesn't mean its better. The 2006-2013 is350 is faster than any gs350. Any new is350 2014 up. And Any Rc350.
As far as handling who cares. The 2is on coil overs would be better than any gs350 or Rc350 on coilovers mostly due to weight. But consider the is f if you want a good handling lexus.
Also you picked the worse stats on the revised is f.
He's not discussing straight acceleration times. Of course the IS350 will be faster, it has the same powertrain in a lighter, smaller car. It's going to accelerate more quickly.
What he's talking about is slalom time, meaning how quickly the car can traverse a slalom as a measure of handling.
The GS is a much stiffer platform than the 2IS platform, as is the 3IS obviously. All you have to do is drive one to see that. Why would anyone care? People who buy sport sedans definitely care.
Haha you guys are funny. Indeed the 2is and 3is is faster to 60mph is true. 2is and 3is are lighter but comes with same engine or almost same engine as 4GS.
But! I can assure you the 4GS had a better suspention with grippier tires amd will out handle both 2is and 3is. Weight and size matter less when your actually turning.
Why do I know? I have owned both a 2is and a 4gs and take both to the track many times and on a very techincal racetrack the 4gs does better at full tilt. The 4gs suspention has better turn in characteristics and better grip therefore better handling. I have also gotten 3is loaners when I servicey car and when I take the 3is to my favorite roads i can deffinatly feel less grip when taking a turn hard compared to a 4gs. The fact that the 4gs can out handle its little brother is a testament of how well engineered the 4gs are.
I am sure when the new generation 4is comes out, with a little bit of tweaking by Lexus should get better and may surpass the 4gs in the handling department.
Back in 2009, I almost purchased a 2003-10 E60 5 Series.
The old 5 Series was so light, it was pin sharp, yet reasonably comfortable and quiet.
However, the light weight caused the E60 to falter when it came to safety.
Thus, I own all four 2IS, 3IS, 3GS & 4GS.
The IS and GS share platforms, such that the old 2IS and 3GS were over 220 lbs lighter than today's models.
Thus the old models were fractionally quicker accelerating, by 1/10 or 2/10 of a second etc.
Chassis dynamics is more complicated.
My old 2IS is lighter with quicker turn-in and more terminal grip on the skid pan, however at the limit, the 2IS would more suddenly and less predictably snap its tail, such that we say that the old 2IS handling was not as good.
My 3IS is much more controllable at the limit, and far safter to drive at the limit.
My old 2IS ride is too firm; my missus new 3IS rides superbly.
In fact, the 1999-06 1IS had the very best turn-in, and terminal grip, but was poor for both ride and noise.
The GS's are more complicated.
My old 3GS had a considerably lighter platform, and it flexed, creaked and rattled considerably, such that they used much softer coils on the old 3GS, hence the turn-in was so sluggish, though the terminal grip was good, and possibly better than my 220+ lbs heavier 4GS.
My 4GS has pin sharp steering, and should do the slalom quicker than my old 3GS, but as far as terminal grip goes, I'm not quite sure - the 3GS could actually outgrip the 4GS on the skidpan thanks to its lighter weight, but then the 4GS has firmer springs, firmer dampers, and lower profile tires.
At high speed cruising, the 4GS is much better damped and controlled than the 3GS, but at 40-60 mph, the 3GS rides far better than my 4GS.
As for who handles better? IS or GS?
Both IS's outhandle both GS's.
Old GS outrides IS, but strangely, new IS actually rides more compliantly than new GS!
Current model GS is very firmly sprung, and even more so if you compare back to back with E350, 535i/540i and Audi A6 3.0T Supercharged AWD.
It's for this reason that 4GS outhandles the competition hands down, whereas 3IS can handle a bit iffily compared to lightweight 3 Series.
Also the 3GS V6 outhandles the 3GS V8, the latter of which is way too heavy on the nose, resulting in sluggish turn-in, and less terminal grip too.
I have never driven the 2IS F V8, but I would expect the 2IS V6's to outhandle the 2IS F V8.
May as well throw in hybrids too while we're here.
Old 3GS450h was a performance hybrid with bigger battery and bigger electric motors, so out-accelerates new 4GS450h which is really only a "GS400h", ie an economy hybrid.
However, old 3GS450h has a ridiculous boot, and higher fuel consumption.
The dynamics is the same as described above, though 4GS hybrid is relatively lighter thanks to both denser NiMH battery, yet fewer AH capacity.
Because IS and GS share platforms, the IS can be a bit heavy, while GS a bit light.
Because 3 and 5 Series use dedicated platforms, 3 Series quite light, while 5 Series quite heavy.
If you ask me, who handles better? Old 2003-10 E60 5 Series, or current 2012-19 4GS? Probably the lighter old 5 Series.
However, remember the old 5 Series crash safety performance.
Life is a compromise....
.
He's not discussing straight acceleration times. Of course the IS350 will be faster, it has the same powertrain in a lighter, smaller car. It's going to accelerate more quickly.
What he's talking about is slalom time, meaning how quickly the car can traverse a slalom as a measure of handling.
The GS is a much stiffer platform than the 2IS platform, as is the 3IS obviously. All you have to do is drive one to see that. Why would anyone care? People who buy sport sedans definitely care.
You must have missed how many numerous times the thread starter referenced 0-60 times and 1/4 times. That was what i was in reference too with my initial reply. My apologies as i replied to his last post. Which is only in reference to handling.
As far as handling
True true. But they're are better handling sport sedans by far. The isf around the nurburgring wasnt necessarily great. No stock is350-gs350-rc350 will be setting slalom records. F sport or not.
Once you start modding suspension the lighter smaller 2is is350 will have the weight and handling advantage.
Keep in mind these are automatic v6 heavy sedans. All of them. At the end of the day who cares. There are MUUCH. Better handling sedans in this segment.
Please keep in mind the isf run around the nurburging was about as fast as a cobalt ss turbo.
And stock for stock ---
any year stock isf will out handle any year stock gs350-is350-rc350 under real world track conditions or street.
In the handling department the lexus automatic v6 sedan leaves much to be desired.
As such keep in mind buddy---- . Its a automatic V6 lexus sedan. I'll reiterate ''''''' WHO CARES'''''''. Im guessing you care?
Apparently you think these are performance sedans and so....The fact remains
In real world driving a 2007 is350 with full bolts i.E ppe headers and joe z exhaust with coilovers will out handle and out accelerate a 2015 gs350 fsport with full bolt ons and coilovers.
Over all the 2is is350 is a better value if you want performance. Its hard for gs350 owner to stomach. Heck even 3is dislike that the 2is is faster.
All that being said i'd take a 2015 gs350 fsport over just about anything lexus offers. Its a good handling luxury sedan.
The gs is meant as a good handling luxury car. The smaller is350 was meant as a performance sedan Upon intial release in 2006. Neither though are ''performance sedans'' unless your a simp who knows little of performance.
The isf and gsf are performance sedans. If you want a performance sedan buy a gsf. No one will argue its s better performance sedan than the isf.....
05-24-12 | 04:32 AM
