Lexus IS-F with test results (looks pretty threatening!)

[gbb357]

Originally Posted by sdiver68

This discussion is a big part of the reason why 0-60 is such a dated measure. Use 1/4th times and speeds instead.

Originally Posted by CarandDriver

C/D TEST RESULTS:
Zero to 60 mph: 4.2 sec
Zero to 100 mph: 9.8 sec
Zero to 150 mph: 24.7 sec
Street start, 5–60 mph: 4.6 sec
Standing ¼-mile: 12.7 sec @ 114 mph
Top speed (governor limited): 172 mph
Braking, 70–0 mph: 159 ft
Roadholding, 300-ft-dia skidpad: 0.92 g

And in comparison with M3. Just so you know, the M3 had gotten better figures than this already with the latest comparison test that C&D have conducted. I'm almost sure they'll get even better numbers in the future.


Here it is.

[sickbimmer78]

Road&Track just release their review on IS-F.
"The 8-speed transmission helps the IS F achieve its remarkably quick acceleration numbers: 0–60 mph in just 4.4 seconds and the quarter mile in 12.8 sec. at 113.3 mph."
"Its 71.2-mph slalom speed is damn impressive for such a heavy sedan (3825 lb.), eclipsing not only the Audi RS 4 (68.9 mph) but also the Porsche Cayman S (70.6 mph). The 911 Carrera 4S barely edges the Lexus, at 71.5 mph. "

http://www.roadandtrack.com/article....rticle_id=6177

I would still choose E92 M3 over IS-F. But still an impressive car.

[JEllis]

Impressive.

I for one am happy there are so many great performance choices.

I really dislike parts of the ISF's overall looks. However, I dont think it is ugly. The interior is actually quite beautiful and sporty. I perfer the M3 though as well. The MDCT will only further improve the M3's impressive performance.

Jason

[ToothDoc]

Originally Posted by swamp2

I'll give you a big hint.

Car, 1st gear ratio, final drive ratio, gear ratio product
M3:...4.055...3.846...15.6
IS-F:.4.596...2.176...10.0

That is a 50% advantage in torque multiplication for the M3! When you want to determine instantaneous accelerative wheel torque (and force and then F=ma for vehicle acceleration) the wheel torque is simply multiplied by the product of the gear ratios (there is some scaling as well but that is not important to do a simple A-B comarison). So M3 torque in 1st gear x gear factor = 295 ft lb x 15.6 = 4602 ft lb. IS-F torque x gear factor = 371 ft lb x 10.0 = 3710 ft lb. No surprises here! Add in the much higher redline and you will see more of the picture. Hope that helps.

Swamp, I see your error - it is the final drive ratio. It is closer to 3.0 actually. If you change that, your numbers will DRASTICALLY change. I thought it looked a little suspicious - the IS-F only goes 30+ in 1st and barely 60+ in 2nd gear.

[GregW / Oregon]

Originally Posted by ToothDoc

Swamp, I see your error - it is the final drive ratio. It is closer to 3.0 actually. If you change that, your numbers will DRASTICALLY change. I thought it looked a little suspicious - the IS-F only goes 30+ in 1st and barely 60+ in 2nd gear.

Good catch--2.937 to be exact.

[ToothDoc]

Doing some rough approximations... The IS-F has a definite torque advantage in every gear over the M3. Wow, this totally changes swamp2's numbers... that 3710 ft lbs becomes over 5000 suddenly! Post up the new numbers swamp2!!! I'm curious - I'm not trying to start another argument, but just curious.

[footie]

I will look forward to one turning up at one of Gustav's events, though I doubt the Lexus will win..........well does anything ever win against BMW at these.

No, on pure performance figures the Lexus will be the one to beat along side the C63 with the M3 and RS4 close behind, though I doubt it's handling finesse will concern BMW much.

[Pancho]

The IS-F can sure post solid performance numbers comparable to the E92 but the car is ugly. It is an aberration compared to the beauty of the M3.

[mkoesel]

Originally Posted by footie

No, on pure performance figures the Lexus will be the one to beat along side the C63 with the M3 and RS4 close behind, though I doubt it's handling finesse will concern BMW much.

True, but I think M-DCT might level the field, or at least make it much closer.

[UltimateBMW]

^^ Truth.

[chonko]

Originally Posted by footie

I will look forward to one turning up at one of Gustav's events, though I doubt the Lexus will win..........well does anything ever win against BMW at these.

No, on pure performance figures the Lexus will be the one to beat along side the C63 with the M3 and RS4 close behind, though I doubt it's handling finesse will concern BMW much.

I will surprised if the IS-F and C63 fail to lead the M3 and RS4 on straight-line performance considering the displacement of their respective engines.

[gadget]

Originally Posted by mkoesel

True, but I think M-DCT might level the field, or at least make it much closer.

The C63 with an auto will probably still be slightly faster 0-60. In other words, lets hope that neither Lexus or MB add a DCT tranny to their cars.

has anyone seen any indication as to whether or not either MB or Lexus have plans to add a DCT. I believe there was a post several months ago that hinted the MB would offer one in the future.


p.s. As a former IS300 owner: The IS-F is FUGLY, good thing AC Schnitzer doesn't tune Lexus, that would make it even worse

[swamp2]

Originally Posted by ToothDoc

Swamp, I see your error - it is the final drive ratio. It is closer to 3.0 actually. If you change that, your numbers will DRASTICALLY change. I thought it looked a little suspicious - the IS-F only goes 30+ in 1st and barely 60+ in 2nd gear.

Excellent work! I am happy to admit this input error instead of dealing with the impossibility that physics does not work. Thanks. The corrected FD ratio does get the numbers closer to the C&D numbers but it still is not enough. I ran a bunch of cases to demonstrate this.

1. M3 6MT std. simulation parameters
2. M3 M-DCT with improved shift times and all gear 7 gear ratios fairly optimized for acceleration
3. IS-F std. simulation parameters and corrected FD
4. IS-F with spectacularly low automatic transmission loss figures. I used lossed almost identically low as a MT. This is probably being optimistic towards how good the 8AT can be. Of course corrected FD as well.
5. IS-F, same as #4 with 435 hp and 385 ft lb torque.

The conclusions are simple and quite similar to my previous conclusions:

• As you can see the run very close to actual car performance is run #5.
• A very good automatic alone with the stated hp and tq is not enough to get the times obtained by C&D.
• It is most likely that car has a combinaton of a very advanced, low loss automatic transmission and some under-rating, maybe as much as 20 hp.
• The M-DCT and IS-F are going to be absolutely neck and neck, but with numbers like these from C&D the IS-F is going to generally outperform the M3 6MT in a straight line.

[ToothDoc]

Looks about right - except I don't think your software is allowing for "launch" techniques. If you notice, all your 5-60 mph is FASTER than your 0-60mph times and with proper technique, clutch slippage or torque converter slippage, 0-60 is typically faster than 5-60. It is also noticeable on the 60 feet times - I'm sure the IS-F AND M3 is capable of 1.9 second 60' times. My stock IS350 with Dunlop Sportmaxx on stock rims has hit 1.91 seconds a couple of weekend ago (no weight reduction).

[ToothDoc]

BTW, thanks for the update - this data makes a lot more sense too.

[swamp2]

Originally Posted by ToothDoc

Looks about right - except I don't think your software is allowing for "launch" techniques. If you notice, all your 5-60 mph is FASTER than your 0-60mph times and with proper technique, clutch slippage or torque converter slippage, 0-60 is typically faster than 5-60. It is also noticeable on the 60 feet times - I'm sure the IS-F AND M3 is capable of 1.9 second 60' times. My stock IS350 with Dunlop Sportmaxx on stock rims has hit 1.91 seconds a couple of weekend ago (no weight reduction).

Once again, not my software, publically available software that is for sale. I just really like it a lot.

The software offers a variety of launch techniques for both automatic and manual transmissions. It also has an optimization feature that can optimize the launch rpm to minimize one performance figure or another. I always optimize launches, btw. All that being said launch is the trickiest part of the physics to capture with the clutch and tires spinning/slipping and all of the non-linear effects. The other problem is just a matter of a sort of a numerical signal to noise effect. Getting the answers absolutely correct when the times and distances are short and much of the error is during launch is challenging (i.e. just not going to happen). Surely the longer distances and times are more accurate than things like 60' time. Furthermore the software is better at predicting changes or relative performance rather than absolutes. Even so, the absolutes are generally within a couple tenths, which is probably less than the test variation among a set of typical journalists!

Thanks again for your contribution to improved simulations.

[footie]

swamp2,

I think your estimates for all cars are a little low, especially at higher speeds. On at least 3 tests the M3 has better 25.6s to 150mph yet in your figures it's a full second slower that that, the same applies to the Lexus. We already have tests showing the Lexus better your times and those of the M3 so why sugar coat it in the M3's favour.

I do believe that the M3 with DCT will be a little quicker but I doubt BMW will optimise the gears purely for acceleration, best guess would estimate the first 6 gears staying basically the same with 7th just increasing it's top end and long distance economy. I reckon the only real improvement between manual and DCT will come from the shift times which I reckon your figures are ever so slightly optimistic as the car will have only changed gears 4 times not 5.

[gbb357]

Originally Posted by footie

swamp2,

I think your estimates for all cars are a little low, especially at higher speeds. On at least 3 tests the M3 has better 25.6s to 150mph yet in your figures it's a full second slower that that, the same applies to the Lexus. We already have tests showing the Lexus better your times and those of the M3 so why sugar coat it that in the M3's favour.

I do believe that the M3 with DCT will be a little quicker but I doubt BMW will optimise the gears purely for acceleration, best guess would estimate the first 6 gears staying basically the same with 7th just increasing it's top end and long distance economy. I reckon the only real improvement between manual and DCT will come from the shift times which I reckon your figures are ever so slightly optimistic as the car will have only changed gears 4 times not 5.

Must you really ask that, isn't obvious.

[gbb357]

Originally Posted by ToothDoc

Looks about right - except I don't think your software is allowing for "launch" techniques. If you notice, all your 5-60 mph is FASTER than your 0-60mph times and with proper technique, clutch slippage or torque converter slippage, 0-60 is typically faster than 5-60. It is also noticeable on the 60 feet times - I'm sure the IS-F AND M3 is capable of 1.9 second 60' times. My stock IS350 with Dunlop Sportmaxx on stock rims has hit 1.91 seconds a couple of weekend ago (no weight reduction).

I've been saying this from the begining. No software out there can really replicate "launch techniques" because it's a human factor. Reaction times makes a huge difference. Like the example that i've posted in the "regression thread", when i took my car in a track the best 1/4 mile that i got was 15.9 & 16.0. But when my friend drove my car who is much more experience than i am, he was able to do 15.4 and 15.5. The same applies to a track course, the driver factor will significantly have a huge difference on how fast or slow a car will perform.

[lucid]

Originally Posted by gbb357

I've been saying this from the begining. No software out there can really replicate "launch techniques" because it's a human factor. Reaction times makes a huge difference. Like the example that i've posted in the "regression thread", when i took my car in a track the best 1/4 mile that i got was 15.9 & 16.0. But when my friend drove my car who is much more experience than i am, he was able to do 15.4 and 15.5. The same applies to a track course, the driver factor will significantly have a huge difference on how fast or slow a car will perform.

Sure, but you can input values for launch parameters that represent the best a human can do to model the best possible case. That is okay since the published empirical data are obtained through best case scenarios to begin with anyway--meaning the mags will try to use expert drivers and do several runs to arrive at the best outcome. How representative all that might be of real-life driving is another question. But the published data do not address that issue either.

[gbb357]

Originally Posted by lucid

Sure, but you can input values for launch parameters that represent the best a human can do to model the best possible case. That is okay since the published empirical data are obtained through best case scenarios to begin with anyway--meaning the mags will try to use expert drivers and do several runs to arrive at the best outcome. How representative all that might be of real-life driving is another question. But the published data do not address that issue either.

Car mags will always show the best performance a car can do, that is their job. But like you said, it does not represent real world driving. I can never do 4.3 on the M3, not with my experience, i just don't have a good reaction time on the track and i usually end up spinning the tires a little bit which could easilly lose 0.2 sec, at least.

[enigma]

There is a good reason that a lot of drag racers use automatic transmissions.

1: They are vastly easier to launch hard.

2: You don't lose time shifting when you could be accelerating.

3: They are more durable. Launching a manual car is hell on the clutch.

4: The torque converter provides extra gearing at low speed. It effectivly multiplies torque when the car is launched or right after you shift to a higher gear.


The reason that maunals used to win a lot of contests is because they were more efficient at turning engine power into thrust. i.e. fewer mechanical losses. But lest just say they were 5% less efficient than a manual and lets say you need 0.3s to shift a manual during which time you are not accelerating.

For a car that needs 5s of in gear acceleration a manual would take 5.0 + 0.3s or 5.3s while the auto would need 5 * 1.05 = 5.25s

Assuming 4.3s of in gear it becomes 4.6 and 4.5