TF109B

I guess you missed that GIANT scan of the 'supertest' with the pre-production LFA that Rolla put up numerous times in other threads.

Yeah my argument isn't that the LFA loses out on straights or not. It's that it already corners higher than the 458 etc. So there's no place to go but up. I find it funny that the 458 could pull away from the LFA so much on straights. Regardless of the HP difference, which is all but 10hp. The wing isn't pushing the car down that much to slow it down. I'm thinking either the driver wasn't really pushing the LFA as hard as he could, or the Ferrari is making more power than what it leads off. Which wouldn't surprise me given what Autocar, Chris Harris and other sources have said about Ferrari and their 'optimum performing cars'.

jpvarghese

iTrader: (1)

Agreed, but if the car is already out cornering the others, the stock set can't be as bad as it's being made out to be. Perhaps the real issue isn't the tires, but the drag, if that could be considered an issue. I won't put too much weight on ring times because the best times are set in the most ideal conditions. With the ring being such a varying track in elevation and temperature, replicating alleged times is almost unreplicable.

The chassis and downforce is only effective to how much grip the tires allow. That's the limiting factor. You cannot explicitly pinpoint the LFA's handling characteristics to just it's chassis and downforce and not address how incredible the stock, '****ty' tires must be to handle those loads.

Changing tires won't affect how much the car 'grips' on the straights (track racing of course). It's main advantages come into play in cornering and braking, which are already incredible on the stock car. How much the car has left in that department is yet to be seen with a tire change. So I agree that changing it up will improve its performance. The car's 'Achilles' is in its high speed acceleration. That shouldn't be an issue for most owners since there aren't too many high-speed circuits like the ring, anyways.

jpvarghese

iTrader: (1)

I'm going to play devil's advocate before I point fingers. Two things. The Italia's downforce is variable at speed. Next, the car has a double-clutch box. People could argue until hell freezes about the latter, but there is numerical proof in its performance advantage. Drag can drastically limit acceleration since it is an exponential function of velocity. On a straightaway, any breaks in velocity paired with drag induced by its aerodynamics will compound the faster you go. It is surely a possiblity. Limiting drag is a big deal. Ferrari spends a great amount of R&D in aerodynamics for a reason, and it's not just to make their cars look pretty.

05RollaXRS

Well, there is well documented evidence that LFA's downforce from spoiler does hamper it's acceleration once it gets past 170 mph (272 km/h).

If you remember, I put down the downforce over the rear axle numbers for various supercars and LFA's downforce over the rear axle was 32 KG at 200 Km/H. Still it is not much, but at speeds over 170 mph, it becomes enormously large. Much higher than any other supercar (except Carrera GT).

Still LFA's acceleration is phenomenally fast and great transmission gearing 1st - 4th up to par with every other car in the class till 260 - 270 km/h.

Horst Von Saurma of Sport Auto called LFA a 'cruise missile' up to 150 mph, but said that LFA could not hit higher than 280 km/h on the last straight due to too much downforce/drag at those speeds, which cost it several tenths where cars like LP570-4 and 458 Italia hit 290 KM/H on the last straight.

Anyway, that is the trade off for more handling using downforce versus more acceleration. I firmly believe that the downforce from the spoiler does cost it acceleration past 170 mph.

Regarding the tires, like I said before Lexus LFA's tires are mid-grade categorized officially as 'Maximum performance tires' while GT3 RS, Aston Martin V12 Vantage, GT2 RS, 458 Italia (optional extra cost on all press cars), GTR, 599 GTO all come standard with what is categorized as 'Extreme performance tires' (Michelin Pilot Super Sport tires, Dunlop Sport GT Maxx 600, Pirelli Corsa and also custom PS2 tires with outer shoulders from the Pilot Cup compound tires), which is one level up in terms of dry grip, but below R compound tires (only Pirelli Corsa tires are R compound on the LP570-4).

The RE70 Potenza tires on Nurburgring edition LFA are also only one step up and categorized as 'Extreme performance tires', which is on par with Pilot Super Sport, GT Maxx 600 etc.

Like 07gsIS350 said, the best compromise would have been to get less downforce from the spoiler and compensate it from more grip from better 'extreme performance' rated tires. Unfortunately, Lexus only fit the Nurburgring edition with 'extreme performance tires'.

07grIS350

We've been wondering about that with the LFA rear spoiler.


Totally forgot about that. So if we removed the 458's result from that test, the LFA's performance looked pretty good.

05RollaXRS

^^^^^

Like I said before in the thread, you can easily swap the Nurburgring edition tires (categorized one level up as 'Extreme performance tires') for comparable grip of all the other cars in the category.

'Maximum performance tires' like S001 are street tires and is what cars like C63, M3, IS-F etc. get so it is simply beyond me why Lexus did not fit the press LFAs with atleast RE70 'extreme performance' rated tires to make it a more fair comparison with other cars or make it standard on such an extreme race-oriented supercar. They decided to reserve it for the Nurburgring edition.

jpvarghese

iTrader: (1)

From what I have seen, it retracts at speed and stays fixed. Otherwise it wouldn't make sense for a fixed wing on the NUR if the standard car has active aero.

TF109B

If HVS's comments are accurate how did the LFA ever achieve it's top speed of 202mph? That doesn't make sense. There are cars with more downforce than the LFA that still hit 200mph. Dude might not have even let it rev all the way to 9000+rpm. He's a porsche driver on top of it. And you never know how good the performance of prototype pre-production units are compared to their production counterparts. We even saw videos of the production car here on these forums a few days ago. Hitting 260+kmh in about 19 seconds, even with a messed up Launch. I have no reason to believe magazines. They aren't half the time even qualified to ring half the cars they test. That supertest is confusing, and misleading IMO. It takes the LFA but 19 seconds to hit 260kmh, yet it takes twice that to go 30-40kmh more? Wings have affects on cars at speed but why would it suddenly have a greater affect take place at speeds over 260kmh? That's BS to me.

05RollaXRS

I don't remember anyone saying LFA can hit 202 mph on Nurburgring?? Well, remember Tanner Foust in "Battle of the supercars" said the samething?? LFA though a lot faster in acceleration still could not beat the R8 V10 in the 1-mile top speed rolling speed test because the "spoiler cost him 6 - 8 mph". There is way too much evidence that the LFA spoiler does cost it acceleration at very high speeds.

The LFA gets to 202 mph on a long stretch. The last straight on Nurburgring is not long enough and it also has an uphill inclined climb making it even more difficult to maintain maximum acceleration. Atleast, it is not long enough for Lexus LFA to clear 280 km/h in the tests so far.

I do know this video is a bit contradiction that since Scott Pruett hit easily 180 mph on an oval inclined track so the only thing I can think is the uphill incline on the last stretch on Nurbugring.

http://www.youtube.com/watch?v=B_nuTlzeUHs

TF109B

I never said they could hit 202mph on the Nurburgring. Lexus' claim is a 202mph top speed. Not on the Nurburgring it can hit 202mph. I said how did they achieve 202mph if the spoiler won't let them get above a certain amount of speed according to some drivers?

I donno why you're trying to argue with me. Weve seen before that these guys don't even know when to shift. Half of them don't adjust the shift speeds, just put it in sport and go. Tanner couldn't even get the LC to work right. The 'Top Speed' test wasn't the standing mile, that was another test altogether. They were on a runway which is a wide open space without trees or anything else to block side winds or head winds. So that top speed run can be iffy depending on the conditions. The standing mile test the LFA won actually over the R8 despite Tanner f-ing up the launch control feature. We all saw how be bogged off the line and let the R8 get away, yet caught back up and passed the R8. Both cars finished around 166mph. I'd say it could be higher if he didn't mess the LC up.

On top of it, in that video, you can see he short shifted up a gear before he even hit 178mph. Why? If he woulda let it run through it coulda hit it faster. I think the pre-prodution units aren't supposed to flung all the way out since they're showcase cars. Just my theory.

05RollaXRS

I think you did not get what it meant when I mentioned Horst Von Saurma.

Horst Von Saurma did not say LFA stopped accelerating on the last stretch of Nurburgring. Obviously, it started out at 135 km/h and went up to 280 km/h on the uphill incline last stretch that is about 3 km long (1.8 mile), but other cars just covered the distance quicker due to less aerodynamic drag.

It is just that according to Sport Auto the acceleration "slowed" down dramatically past 170 mph. Again, that is the rate of acceleration in order to cover the distance and they said after their wind tunnel testing that LFA's spoiler produces too much drag. 37 kg at 200 km/h versus 30 kg for the 458 Italia at 200 km/h.

That is what it meant. I think it is simply physics. High speed acceleration is a function of aerodynamics and when there is such a high obstacle sticking up in the air, it is bound to interrupt air flow and hence have an "anchoring" effect.

I am really hoping to soon see some detailed testing on a production model LFA. The red prototype tested by SportAuto only had 1173 km on it so it was barely broken in. I want it atleast as much as you for LFA to shine comprehensively on all performance tests.

jpvarghese

iTrader: (1)

Cars with more downforce than the LFA, as you say, probably have more power and un-obstructive aerodynamics. Look at how Ferrari does things. None of their current road-going cars have spoilers. They are experts in the field of aerodynamics. BTW, which cars are you talking about?

You're making it sound like every test with the LFA was botched and that there's a conspiracy out by the media to make it fail. Using a speedometer to gauge acceleration is also silly.

And you know this as a fact, or are you making an assumption from a test drive video you saw?

The Lexus makes more power than the R8, FYI. You're thinking too much into this. Now Tanner 'let' the R8 beat him off the line and get away? Any difference in the top end because of LC is not going to be significant.

Scott was taking a passenger on a test ride, not a full out top speed test.

TRDFantasy

How good is the high speed handling and stability of Ferrari models at say 200 mph? Is it as good or better than the LFA?

One of the major reasons the LFA has the spoiler is for strong high-speed stability and handling even at top speed. This was explicitly mentioned by the chief engineer as being one of the design priorities for the car.

Somehow I don't think current Ferraris at 200 mph offer very strong stability and handling.

TF109B

I donno why you want to pick apart my posts, but it's useless dude. I'm not on here for an internet fight. Just sharing my views on things. There's little doubt in my mind that half the guys that have driven the LFA aren't knowledged into it the way some of us are. For instance, the shift speed ****. There's journalists out there who've tested it and haven't even mentioned it, brought it up, or even knew what it was for. They mention you can select 'sport' 'wet' 'auto' but say nothing about the other little **** to the right. Key things overlooked. I never said Scott was on a top speed run either. Why are you putting words in my mouth? I'll tell you what. I just won't reply to your comments anymore. All they seem to do is try to bash what others think or say. that aint cool cat.

If you watched the Battle of the Supercars episode, you saw that the 1 mile shootout was just that- a shootout. That means both cars side by side. I'm guessing you didn't watch the episode or just failed to realize that with cars that are almost equally equipped in power and weight, getting a jump on another car is a big deal. Like I said. Tanner Foust messed up the LC. The R8 pulled off the line big time. Had a few car lengths on him. But the LFA caught up and passed the R8. What's wrong with stating that? Oh, the LFA has 30more horsepower, wow, it's expected to go 'much faster' right? Come on guy, it's things like that in your replies that make it not even worth responding to. Are you here to talk about the LFA or discredit it for whatever it does or doesn't do? That's what it seems like to me. I'm just here to have a decent conversation on a car we here all seem to like, some even love; but we have some who come here just to bash others posts and act as if they're scientists or aerodynamicists. It's not cool, and it makes the threads useless.

My point in bringing this stuff up is that these are still pre-production units. So we don't know for sure what Lexus said they can and cant do. Someone on another forum site mentioned that at the track meet, they weren't allowed to change the shift speeds on the LFA. And that the settings were somewhere between the fastest and slowest setting. In other words somewhere mid-way. All I've heard is how the LFA shifts slowly on other forums, and that 'dual-clutches' are way faster. I'll tell you what dual clutches are. They're basically automatics. They engage another gear while still in the gear that is currently being used. Now if the LFA can shift in .2 seconds, while blinking an eye takes between 0.3-0.4 seconds http://www.ehow.com/about_5199669_fast-blink-eye_.html, then it's faster than a blink of an eye. I repeat, that's FASTER than blink of an eye. Your eyes blink at about two times the speed of an LFA shift. I donno about you but shifting twice as fast as a blink of an eye is still plenty damn fast.

All the arguments you come up with can be countered with regular searches on the internet. I donno why they even need to be brought up. The stuff you're saying has been discussed, rehashed, discussed etc. over and over again. So come on, lets get this conversation back on track. I see no reason to believe the LFA won't be able to compete with cars like the 458 the MP4 the Superleggera etc. and the Nurb edition should go even beyond them. I'm willing to bet on it.

jpvarghese

iTrader: (1)

I hope I'm not misunderstood. I'm not 'ragging' on the LFA because it has a spoiler. They are very effective, but come with a tradeoff. I cannot speculate on Ferrari's performance at 200+ mph, because I don't have the data. However, I know that they've had fantastic results increasing downforce without increasing drag. That sounds counterintuitive, but this is what they've done. In high speed acceleration, it's completely about minimizing the effects of drag.

Edit: Here's an article from WIRED.
As a matter of fact, I have an extensive science background. So I beg your pardon for taking apart your posts. All I've seen were what sounded like excuses. I'm in no way trying to disqualify the car, but qualify it with science and data, not hearsay and speculation. What makes threads useless is BS. I apologize for coming out rash.

Regarding the transmission. It is very quick. Agreed. The twin-clutch's greatest strength is that the engine is NEVER disconnected from the drivetrain. Pumping losses from that alone will cost the car's momentum. That's the killer. Taking an example from drag racing, a manual car will require much more power to compensate for the momentum loss b/w shifts when compared to an auto. The quickest shifting single-clutch gearbox will have to live with that reality and there's no way around it, but this is what gives the driver the 'feel' characteristic Lexus was looking for.