Koma

iTrader: (3)

First production vehicle to use a dual clutch transmission was the MKIV VW R32 in I think 2003.

You make some valid points but no one really knows for sure except Toyota. When Toyota said that they chose a single clutch over a dual clutch because of the shifting feel it actually holds some truth. DSGs have a much smoother shift feel than a single clutch.

Toyota switching from aluminum to CFRP makes sense and I don't think it was a "follow the bandwagon" move. An aluminum LFA was too heavy and didn't meet the performance that Toyota wanted. It would cost a lot to switch over to such a technology so if they did not want to pour money into a non-green lit project then they would've stuck with the aluminum. Toyota purchased a rotary loom to create this car so I don't think money was a concern.

I'm not quite sure why Toyota went without direct injection but I can't imagine it would be extremely hard/expensive to design heads to accept direct injection.

I'm skeptical that Toyota was really just gluing this project together when they decided to produce the LFA. Toyota has the money to invest into this car. I do think you have valid points and it's possible they are true but I'm still leaning towards that Toyota made the right decisions.

LexFather

Valid points but lets remember this is Lexus, not Ferrari. This is JAPAN's first entry into something like the LFA, there was no benchmark within the company. As they stated their most extreme car was the Supra!

4.8 liters and 552hp is still nothing to sneeze at and the LFA redline is fantastic. DI might possibly lower the RPM in exchange for power.

Chris Harris had an editorial about Dual Clutches and he hates them. Yes they will make the car faster and shift smoother but to him its boring and like driving a Camry. He prefers manuals of course and things engaging (he loved the LFA).

Surely a LFA with DI and a Dual Clutch would be a faster accelerating car under 100 mph but in expense for its "soul".

Its why PDK won't be in Porsche GT cars. It doesn't fit the car even if they would be faster.

Great points, not going to dismiss them at all. There just is no one way "blueprint" to make an exotic

rominl

iTrader: (4)

great posts BNR34, some very good arguments

like others said, on some points no one will really know the answer unless you are the one high up in toyota, but that's just news buried forever.

but regarding the single clutch vs dual clutch, personally, i do always think it's a bit bs on toyota's side when they gave out the reasons for sticking with single clutch. they focus so much on the track performance of this car, and it's pretty clear that a well designed dual clutch will perfect far better, so it only makes sense to have dual clutch system in the car

Mister Two

No way was it a cost issue. Ever thought about why DSG is never used in a race car? You probably missed the part where the LFA chief engineer said that they did already fit a DSG on the LFA for evaluation, and not only was it too smooth for their liking, but also the engine response was not as good due to more parasitic loss from the more complex internals of the DSG, with the weight penalty being another reason.

Can't find that article right now but I'll post the link here once I find it.

BNR34

iTrader: (1)

Thanks for the confirmation, yeah GTi/R32 sometime in early to mid 2000.

I am aware. I just think no one actually prefer a rough shifting tranny.

Well not necessarily "follow the bandwagon", but the #1 priority of a super car is really the performance spec. So if the performance spec don't match the competitors, they have to fix it. I am guessing switching to CFRP happened earlier in the development cycle, another reason is Toyota want the experience of learning about CFRP manufacturing for their future main stream production cars, so they use the LFA as an opportunity to do so.

Nothing is hard and obviously they know how to do it, but everything take times and money.

Of course Toyota didn't glue this project together, I am not saying that at all. Toyota is the most profitable, most well off car manufacturer in the world. They have the money and resources to do anything if they wanted to. The LFA is absolutely state of the art back in 2005 when it was ready for production. Toyota didn't skim a dime on the development, they made it the best humanly possible for a $400k exotic sports car and they did it, in their 1st attempt!! BRAVO!

What I think happened and this is all I am saying here. At 2005, Toyota was waiting to release the LFA after they win in F1, the LFA was to celebrate their victory in F1. But they can't win in F1 year after year........that's why the release of the LFA got dragged out. They finally gave up F1, so the event to celebrate never happen. They got this completed LFA project, they have to decide either produce it as is, or not produce it at all. They are not spending any more money on it to farther develop it to update it to 2011 standard, not that they don't have the money to spend on it, they just don't have a reason to anymore.

Also the whole F1 effort, LFA project are nothing but Akio Toyoda's pet project for fun, is not for profit. After dumping billions of dollars into having fun, enough is enough. Not to mention Toyota got all these recalls, lawsuits to pay for in these last year or 2. Updating the LFA to 2011 standard is the last thing on their mind. I am surprise they even green lighted it for production. I am glad they did though, it is a lovely car. And definitely an alternative for someone like me who can't afford Ferrari maintenance/up keep

Mister Two

You forgot the fact that the LFA's V10 is derived directly from the Toyota F1 engine, which has no DI either. Toyota has had DI engines in production cars since 1998, so being a 10-year-old design isn't a reason for the LFA not to receive the DI technology.

Mister Two

Guys please realize I'm never talking in this thread about the GT-R as a car, but as a marketing tool for Nissan. In this regard it is very comparable to the LFA. Both marques are not previously known as high-end performance leaders and have everything to prove in the performance department to use their halos cars effectively to help the respective marques climb up the performance ladder. Lexus has so far done a great job in promoting the "exoticness" part of the LFA, but they could've done better in showing the LFA's best tangible quality--its track-focused performance IMO. That's all I'm trying to say.

05RollaXRS

Exactly.

The reason is that the concept of dual-clutch is very flawed. It works great in every day driving, but it falls on its face in racing and other track oriented events.

Two reasons here:

- It is much heavier and "fragile" than the single-clutch automated transmission.

- The dual clutch concept requires pre-selecting the next "anticipated" gear using the second clutch (1, 3, 5 odd gears are handling via clutch 1 and even 2, 4, 6 are handled by clutch 2). However, this idea falls on its face when the "anticipation" of the computer goes wrong where the user instead of upshifting, quickly abruptly downshifts two gears (pre-selected was 5, but the driver downshifts 4 to 2, say). That sends a dual clutch tranny into a frenzy to swap out the gear and from clutch 2 and let clutch 1 do the downshift. A single clutch anticipates nothing. It simply shifts the gear, the driver wants and although, its shift times are marginally slower than DSG, it would consistently shift very fast in every scenario.

That puts a huge lag in downshifting process.


Also, I noticed LFA engine being called "outdated" because it does not use direct injection. That is ludicrous. LFA engine is revolutionary and it has accomplished something no other engine has, which is a V10 with such a big displacement only the size and weight of a 3.0 Liter V6. It is a tiny engine that puts out so much power. If Lexus wanted more power, Lexus/Yamaha can easily squeeze out another 20 - 30 HP, but that will result in increased emissions.

Secondly, high revving cars with direct injection have had a huge issue of "carbon build up". Lexus most likely wanted to build the most reliable engine possible and with the wide spread "carbon build up" issue, it would almost be impossible to create a reliable DI high-revving V10.

I also posted a comparison of LFA dyno vs 458 Italia dyno and showed that LFA engine produces way more torque between 6000 - 9500 rpm (10 - 15 wheel torque). The 458 Italia also was cut off at 9000 rpm while LFA kept going till 9500 rpm. The 458 Italia engine is stronger and puts out more torque in the 3500 - 4500 rpm region, which the midrange. The peak of 398 ft-lbs is more of a spike in the midrange, but the torque curve falls after 5000 rpm and then stays flat. Lexus wanted to build a "top heavy" V10 and everything about 'revs' so they decided to go with a small 10 cylinder design sharing 4.8 Liters combined that could be filled up fast, which facilitates revving up fasterl

BNR34

iTrader: (1)

Thanks for concurring with me guys

Lately I have been obsessed with the 458 and after reading that very nice article on the 599 vs. LFA last night, I felt compelled to let all that out, now I feel dumb on wasting all morning typing all that

After all that what seems to be LFA bashing from me, I have to say I love the LFA, I would own one in the future if I have the opportunity.

That engine scream is absolutely amazing, that is the most important aspect in an exotic car in my opinion, 2nd is styling. The slightly lower power is not important, and I can overlook that clunky tranny for that orgasmic scream

I just hope they will make the roadster version, you can hear the scream better without a top

bitkahuna

iTrader: (20)

thanks for the good laugh.

must be why the veyron uses one, because it's so fragile.

http://www.gizmag.com/go/4909/

bitkahuna

iTrader: (20)

BNR34, i agree with you, i wish the LFA had a DCT, but i'm sure a production LFA won't be quite as harsh as the test mules or the BMW SMG for example.

the LFA is a unique and incredibly well executed design for so many reasons. i've been in ferraris, porsches, and the LFA, and the LFA was hands down more impressive.

Mister Two

I disagree with 05 on that fragile point either, but I think the reasons I mentioned still stand. Just think why ALL modern race cars still choose to use automated manual and not DSG.

Heck, even the GT-R switches to a 6-speed automated manual when entering the Super GT race series.

05RollaXRS

I was talking in relative terms. It was supposed to be a comparison with a similar single-clutch design especially when you factor in the torque-handling capabilities. BMW, for example has a much lower torque limit rating on the dual clutch transmissions than it did on the older SMG7 transmission or even the SMGII where E46 M3's are running 1000 whp with turbos on them. But, yeah SMGII was very very clunky so I agree it was not the greatest transmission.

The single-clutch design can sustain abuse a lot more than the dual clutch. Mechanical efficiency is another thing. VW wanted to put comfort and convenience first and dual clutch works much better in daily driving.

Veyron, ofcourse is a GT car or an Autobahn rocket and almost no one will take a 4500 lbs GT car to the race track very often.

BNR34

iTrader: (1)

You must have not heard Veyrons are crashing everyday because of tranny failure.........kidding LOL

BNR34

iTrader: (1)

Guys, those single clutch tranny in race cars are Sequential manual transmission, they have nothing in common with single/dual clutch automated tranny in street cars