05RollaXRS

It could be plausible. But, the coefficient of drag measured with the spoiler deployed is alarmingly high at 0.40 (by comparison, most fixed spoiler supercars have CD of what LFA has with the spoiler retracted). As a comparison, an X5 M SUV has a drag coefficient of 0.38. Do you see my point? It seems almost as if the spoiler begins to act like a brake at very high speeds a la Maclaren Mercedes SLR. I am 100% sure, it can very easily be fixed through altering the angle of the spoiler, which is titled too much.

However, it could be possible that the red LFA was not putting down the power that it should be.

Seeing how this 0 - 300 KM/H is spreading over the internet like wildfire and many people believing everything they read and taking a stab at the LFA without even trying to look for answers when it simply does not make sense. It is impossible for LFA to be that slow. I still believe Lexus needs to stop putting these prototypes out for comparisons/tests since I think they owe it to their customers to finish the product first and conduct all the tests with complete confidentiality.




Thanks for the update. I agree the control should definitely be available to the user with a few preset and tested options available including controlling the angle of the spoiler that gives the best combination of top end acceleration and downforce. If the user wishes to retract the spoiler, it should be available to him.

The other thing to take back to Lexus is definitely having a launch control system, which is very critical that you guys can stress to Lexus about.






I don't think so. Lexus races the LFA with stock power of 552 HP in the SP8 class so definitely Lexus builds LFA engines that put down the proper power. Most of the Lexus dynos I have seen seem to be exactly where they should be. For example, IS350 dynos around 245 - 250 wheel HP, IS250 dynos around 175 - 180 wheel HP , IS-F around 335 - 340 wheel HP etc.

Remember, it is not out of the ordinary to get lower dyno readings sometimes. I have seen some other manufacturers that out of the blue have cars that dyno lower than expected.

TF109B

Wasn't the LFA done on an AWD dyno by Motortrend and made an unimpressive 430hp? I thought it was supposed to be a 10-12% drop from crank to wheels? So this would be more than a 20% drop in power. So even if the dyno was off by a couple percentage points, the pre-production LFAs look to be down on power. If this is the case and it's done for a reason by Lexus, then the achievements done by the car so far speaks volumes.



By this chart we see the GTR making 48 less HP at the wheels than the LFA. Official numbers are 480HP for the GTR and 552HP for the LFA. So what happened to the 72HP advantage of the LFA? Me thinks something is fishy and it aint the dyno- I wish Lexus would elaborate.

MPLexus301

iTrader: (3)

You're correct - than was an AWD Dyno.

05RollaXRS

x 2

He answered his own question. It was quite stupid and ignorant of MotorTrend to not point that out, but they did not want to spend the money to find another RWD chassis dyno to properly dyno the LFA.

LexFather

Guys I have a great idea. Lets take a car we already dislike which is RWD and pit it against a car we like which is AWD and then pit them against one another on an AWD dyno. That sounds fair right?

lol

05RollaXRS

Well, to be fair, LFA won the overall comparo despite the price. LFA destroyed the GTR in all handling and braking tests and also destroyed it in every 100+ mph acceleration tests. That is what truly matters.

I still think LFA's Nurburgring lap time despite being the same as the GTR (which s*cks), is quite an achievement since it goes neck and neck with Ferrari's latest and greatest offering and beats the most expensive Ferrari (599 GTB) by almost 10 seconds. There is no Lamborghini right now that was tested and was faster than the LFA. LP 560-4, LP640-4, LP670-4 all are substantially slower.

TF109B

They did more than just one run, they said they ran it 3 or 4 times in 5th gear to reach what they call it's HP numbers at the wheels. I don't think it's accurate, it was a rhetorical question BTW, but it's certainly not far off. What can you expect? If it was on a RWD dyno what could the difference be? Anyone know for sure? It's been said before that the GTR they think makes more HP at the crank then it's said to be making. I like the GTR, but it's no LFA. They tested the braking distance and it was 94 ft. from 60mph. That's impressive, especially being a loaded LFA without the spec tires.

Mister Two

If you watched the video, you'd see that the LFA is wasting a lot of power to unnecessarily spin its front wheels and the front rollers of the AWD dyno. The dyno result is therefore far off of course, but how far off, no one would know. Hopefully someone else gets to do a proper dyno for the LFA soon.

05RollaXRS

Thanks. I thought it was quite obvious looking at the front rollers spinning using the torque of the rear wheel since it is simulating all four wheels collectively pushing the ground back.

Usually there is a way to switch AWD dynos to RWDs with the push of a button, but the front rollers do not spin in that case. It was quite idiotic of MotorTrend to neither mention it nor request an explanation from them as to why the front rollers are spinning on a RWD car.

For a 552 HP car, assuming a typical 15 - 18% drivetrain loss, the wheel HP should be around 480 - 495 wheel HP.

DeTomaso

I bought Sport Auto magazine today that contains the LFA Supertest. Some remarkable things i noticed:
1) weight with full fuel tank: 1598 kg. The magazine really wonders how it could be this heavy when the car uses carbon fibre, an extremely light engine and titanium exhaust. They mention however the car comes fully loaded with luxuries.

2) 0-62 mph: 4.3 (!) seconds but this is achieved with Launch Control the magazine says. Explanation for the bad time is the very moderate rpm the launch control maintains and this results in a bad compromise between wheelspin and traction. So it looks like the LFA pre production cars are equipped with LC, but that it is badly calibrated.
They did another test later from 0-300 and here the LFA got 4.1 seconds from 0-62, but they didn't mention if this was achieved with or without LC. Also noticed they could only get a 0-62 time of 4.0 seconds for the Corvette ZR1...

3) While the engine still sounds great, they preferred the incredible sound of the Nürburgring racer versions. I was also a bit disappointed when i heard the 'final' sound adjustments they made to the LFA last year. Just search Youtube for the VLN and ADAC 24 h LFA entries and you will probably feel the same.

4) Comparing the LFA to his closest opponent (imo the 458 Italia) on the Nürburgring and Hockenheim tracks it becomes clear the LFA is noticeably faster in the corners, while the 458 leaves the LFA in the dust on the straights due to a considerably higher speed.
For example: on Döttinger Höhe the 458 achieves a top of 295 km/h while the LFA achieves only 275. In the Brünnchen corner the LFA achieves 1.30 G and 114 km/h while the Italia reaches 105 km/h and 1.25G. The end result is the same laptime for the Nordschleife of 7.38 min. Important is that both the LFA and 458 achieved this result without the use of semi-slick sport tyres like the Michelin Sport cup (the LFA used Bridgestone S001). The Nissan GTR (7.38) was equipped with semi-slick sport tyres.

Same story on Hockenheim: the LFA was 0.5 seconds slower than the 458, and 0.2 and 0.1 seconds slower than the GTR and R8 v10 respectively but the latter both used semi-slicks so not really a fair comparison.

5) Sport Auto sums up 3 reasons why the LFA didn't do better: bad Launch control, too high drag coefficient of 0.391 and too much weight. That Lexus is aware of this is evidenced by the lighter Nürburgring Edition, according to Sport Auto.

Conclusion of Sport Auto: if you do not look at the price this is a great car. If you do take the cost into account and the exotic materials used, the actual performance numbers are questionable. However the car has its own character and provides superb handling, feel and luxury.

gengar

Keep in mind that Cd is dimensionless (hence the term "coefficient"), which means that comparisons of Cd between vehicles of vastly different purposes and designs are not particularly useful. The actual drag involves Cd and the area, so a car with very low surface area could have a much higher Cd despite actually having less drag (an F1 car, for example, can have Cd over 1 - of course, this is a number that is also inflated by downforce).

05RollaXRS

Thanks for posting that. I had been really looking forward to reading the details.

- They measured the drag coefficient at 0.34 without the spoiler raised and 0.3981 with the spoiler raised up. The LFA frontal area is very small at 2.01 meter square as most supercars have a much higher frontal area.

- 3500 lbs with that much luxuries in the car (3400 lbs without gas filled) is comparable to a 599 GTB with similar luxuries at 4100 lbs. It is still not that heavy. I guess, Lexus can cut back on some luxuries to keep the weight down. There is no need for 13 speakers in a race-track oriented supercar, I think.

- Very surprised at the launch control not working adequately. I was hoping Lexus will put a good launch control that can easily trim the time down to 3.4 - 3.5 seconds. Still, the same 0 - 60 mph as the ZR-1 cannot be a bad thing.

- I had long seem the temporary bridgestone tires as a limiting factor since most supercars come with semi-slick tires (Michelin Sport Cup tires), which is putting LFA at a disadvantage. ZR-1 comes standard with these semi-slick tires. Lexus should be supplying the test cars with the most aggressive tires they could find.

- Again, I strongly believe the extremely levels of downforce at the very high speed is what costs LFA precious tenths. Maybe, Lexus needs a better compromise between downforce and high speed acceleration.

TF109B

That's weird. It's gotta be an early version of their launch control. Their F1 cars had it and they used to make terrific starts. There's no way that the launch control will hurt the car (3.6 vs 4.2). Me thinks SportAuto might be a little biased towards european cars. Notice the Vette time. 4.0 to 62? Yeah, ok. That's absurd. The vette can hit 60 in 4 flat going up a hill. It's an easy 3.5 to 60 or 62mph. I guess they're going to say the launch control didn't work well with that car either? But it works fine with all the european cars? The Ferrari, less than 3.5; the Porsche, less than 3.5; the lambo, less than 3.5; you see the trend? I don't buy magazines just because of this. Motortrend, Car & Driver, Road & Track, they're the same way. BMW biased (see this ALL the time in C&D), Ferrari biased (Motortrend). It's hard to get the real story when you have publications already rooting for one side. How is it that Auto Zeitung could mangae 3.8 to 62mph? Didn't they not have launch control? Now all of a sudden the (presumably) same car has it and does it in 4.1 at best? It's illogical.

05RollaXRS

I wonder when is BestMotoring going to do a full test and race on Tsukuba circuit for the LFA??? I would love to see Tsuchiya flog the LFA around the track.

Well, imagine what LFA would have done if Lexus had put the Michelin Pilot Sport Cup+ semi-slick tires. Corvette ZR-1, GT2, GT3 RS 997.2 and Nissan GTR were wearing these tires when SportAuto did the test. 7:28 - 7:30 would have been easily attainable for the LFA.

The Bridgestone S001 are considered high-performance tires for luxury touring cars. Not extreme performance tires. I have no clue why Lexus would put these tires on the LFA (BTW, Ferrari 458 Italia comes from factory with these tires as well).

Looks like Lexus put a conservative launch control on LFA to save the clutch from wearing out. Most likely launch control does not let the LFA drop the clutch from over 2500 - 3000 rpm.

LexFather

Thanks!!! Anyway you can buy and ship a copy and get paid back?