mik

Lee,

Agree totally with your last post.

As I see it the only bit you guys are arguing over is whether the torque convertor is offering a gearing-down soltuion.

I think it is. If Lord Mycroft is at 90pmh / 3000rpm cruising (gearing 30mph/1000rpm) and a pesky diablo hoves up behind (don't you just hate that?) then it's izzy-whizzy-lets-get-busy.

Mycroft plants his clog. the box doesn't kick down, but (in 0.3sec) the torque convertor has allowed 6000rpm to be dialled in (where there is probably less torque) but he's now delivering tractive effort at 90mph and 6000rpm. Gearing effectively 15mph/1000rpm. Is this as efficient as a manual box 15mph/1000rpm gear? Nope.....you're suffering big losses to the fluid drive (as you've stated).

Mycroft's gearing has nowhere to go however, and the car accelerates by progressively locking the torque convertor and holding 6000rpm on the tacho. His 15mph/1000rpm gearing is therefore moving relentlessly back towards 30mph/1000rpm, so his gearing advantage is dropping all the time.

How has he achieved greater acceleration then?

By using a fluid drive to "change down". Not in a mechanically efficient way, but there you go. Mycroft's car almost certainly has the torque to outweigh the losses ....but we'll never really know. It's a secret

At the end of the day I'll still choose a manual thanks.

trollhunter

Mycroft
Pepper
forget those race teams what do they know , they didnt even buy soarers to race !!, wait till TOTB2 and you will see the power of the soarer, that guy in the diablo would laugh his **** off if he saw this post and thought back to when that toyota camry thaught he had raced a Lambo , looking/world/rose/glasses/tinted comes to mind , i dont doubt that mycrofts soarer does perform but dont kid yourself .

That was not supposed to be a blatent insult (bit sarcastic maybe) im just trying to say that we all know a played about soarer/supra/skyline will be a very quick car but lets not kid ourselves that we can take on diablos etc, some may be faster in a straight line , some round the bends but all round i'd have to say no , i have driven a 4wd diablo and i can tell you it was awesome, maybe if a pleb was driving the lambo but for it to carry any weight you would have to know the guy and know he was giving it his all .

Pepper

Mycroft, I'd be interested to hear why you think race teams etc favour manuals (as Lee mentioned earlier) if this system is so great...?

Claudius

What do you think, Helmut?

Mycroft

Mik has grasped part of what is going on with the Torque converter... the gearing is different... end of.

Troll has seen a part too, High-stall rate is a major part of the trick, but only ½ of the TCs' mod... there is a very important factor of mods to the TC that effects the Stall rate but, because we are not well versed in Autos' over here is over-looked and we only get part of the benefits that are available. An '8sec' Auto'box car in the States may well have only 700hp and weigh 30cwt his stall rate may well be just 4000rpm... which is still road usable (just)
We try the same thing over here, 4000rpm stall-rate, same tyres and we get a good 9½--10 secs...

A word for 'H' should you decide to join in... please do NOT divulge the final 'element' for the performance jump, anything too readily given away is not appreciated on UK car forums, take my word for it.

Mycroft

You are using in-gear speeds and adding them up... hahaha the 'faults' in doing that are too numerous to go thru...

To highlight just how faulted such things are the German Auto-bild(?) magazine tested the F1 (6ltr. BMW motor) against an Auto'boxed 5.6ltr. Schnitzer 750i saloon (480hp), doing this 30-70 (50-120kp/h) test in real world produced these times...
F1...
Best on the day (last run) 4.0secs,
Worst (excluding complete drive loss, missed gear)(also first attempt) 4.7sec...
Schnitzer 750...
4.0-4.1secs everytime without a dropped cog...

Compare...
the power
the weight
the driveability

So unless you are a top driver who drives an F1 all the time a reasonable driver in the Schnitzer will 'haunt' the F1, just as I did the Lambo (with just 330hp)... real World stuff... not numbers on a sheet.




[Edited by Mycroft - 5/3/2003 2:06:40 PM]

Pepper

###
A word for 'H' should you decide to join in... please do NOT divulge the final 'element' for the performance jump, anything too readily given away is not appreciated on UK car forums, take my word for it.
###

Why?

logiclee

Mik,

Thankyou.

Someone who has grasped what I have been saying.

No matter how you dress things up you have torque, power, gearing, drag(air and mechanical), weight etc. etc. in both Auto and Manual models.

The torque convertor adds in its losses so therfore would need more power for the same performance.
To answer Pepper... Thats why all race and rally teams (except specialised 1/4 mile machines) use Manual boxes even if they control them by computers, add an auto box into a car and you reduce power and torque to the wheels, that is fact!
A fluid coupling is better at feeding in very high horsepower (1000hp+) than a human brain and clutch for the optimum 1/4mile time. A car set up in this spec would be useless as an on road performance car.

You can spec the auto up to give you any gearing you want as you can a manual but the conventional auto will always be hampered by the losses involved with fuid couplings.

I will say again I like automatic cars, buying something like a Jag with a manual box is wrong, the auto suits the Jag but an automatic Impreza sti, Evo, Diablo etc? I dont think so. Performance cars do not need to be compromised by an auto box.

Lee

mik

I'm astounded you're scorning my argument

Go on then...humour me . List some of them.

Can you also tell me (in the mag comparison) what gear the F1 was in, and what gear they were dropping to, and how long the shift took?

In-gear times are taken on a run (ie a 40-60 time will actually start from 30mph and the clock starts when it hits 40). This is to eliminate all "getting up steam" variables.

Measuring a time from a "go" signal is interesting, but makes comparison between cars difficult. Sometimes you want to change down, other times you are in the right gear waiting to squeeze.....

Some cars require turbos to spool up and slushboxes to "adjust"

Is you're whole argument centred on the initlal response your auto provides compared to a manual car that needs to change down?

I know you enjoy a good troll, but it would help the banter if you could be clear on your claims

Mycroft

Such fantastic times are 'sprint readied' times... they do not (even by the testers admission) reflect road times... that is the difference.

On the road... would you drive the F1/lambo/360/355 'like you stole it' on every journey you made?.. what the German times showed is real World dynamics... not 'headline' numbers.

Mik, this whole debate sparked from the encounter I posted on here... read it...

[Edited by Mycroft - 5/3/2003 3:03:37 PM]

logiclee

We can play figures all day but some I just come across are interesting.

The Jag XKR is a similar style of car to the Soarer. Its supercharger setup means it has massive midrange available and puts out nearly 400lbft of torque with 370bhp. The belt driven supercharger should mean near instant response as it doesn't need to spool up. Its auto box is considered to be among the best and weight wise its only 50-75kg heavier than the Soarer.

The Diablo isn't at its best at 30-70mph due to its long gearing, its a lot better suited to 80mph-150mph.


XKR Auto 30-70mph 4.7 seconds.
Diablo GT 30-70mph 3.1 seconds.

The lower powered Diablo SV recorded a time of 3.4 seconds and this included a change from first to second during the run.

So how does the Soarers performance compare with the XKR? Does it have considerably more power than 370bhp or considerably more torque than 400lbft? If not where is the extra performance coming from?

Lee

Mycroft

15miles of real World driving... he doing his utmost to put the POS Jap-mobile away... and he couldn't... if we met now and his car was unchanged, he would be demolished by my car... left bewildered.

Pepper

Mycroft

FYI

Superchargers are at their best in Manual cars.

Turbochargers are at thier best in Automatic cars.

logiclee

Things just keep getting dafter don't they?

Claudius

"H" emailed me back!

He said he doesnt speak good English and hasnt got a lot of time, but turbo and automatic gearbox / torque converter should give the answer away...

Sounds like another Mycroft to me Damn!

LOL

Mycroft

We are both Engineers/Scientists and we take the p!ss all the time... I hope he can find time to come here... it is good sport.

logiclee

1.5 seconds off the 30-70 time by changing a shift pattern and coupling properties......

....Making the 370bhp XKR as fast as the 472bhp 472lbft Turbo Charged, lighter, Porsche 996(911) GT2, even though the Jag has a "Sluggish and power sapping supercharger"

Some black box that.

What's it do to the 0-100 time?
The Jags is 12.5 seconds.
996 GT2 is 8.3 seconds.

Lee

Pepper

Why didn't Jaguar do this themselves?

I wonder if there are any links to sites describing this mod....?

Mycroft

According to the Level Ten brochure.. 10 dead... slightly slower than my own car... damned good in my books...

We 'conventional' GT drivers Front engined rear drive always suffer in that 0-30 or 60foot band, unless we fiddle with the load transfer at take off, which of course with my variable shockers I can to some extent, but we make up for that with better balance overall.


[Edited by Mycroft - 5/3/2003 4:17:16 PM]

Pepper

Can't find anything on their website about XKR's...

http://www.levelten.com/converters.htm

logiclee

The transfer of torque from the flywheel to the input shaft of the gearbox is nearer 100% than it is 99%. Its a direct coupling once the clutch has engaged.

Where is the loss?

The mechnical losses from input shaft of gearbox back are experienced by both Manual and Auto.

For the Auto to be more efficient than the manual it would need the Torque Convertor to be of greater efficieny than a direct coupling.

Lee

logiclee

You didn't have a reply to this bit of my post?

Lee

logiclee

So I have been saying all along the torque convertor multiplies the torque available at the gearbox by revving the engine to a point in the rev range with higher torque than the input shaft of the gearbox(See page 3). It does not make 100lbft into 200lbft.

This is from the levelten site.
On Efficiency Levelten agree that a direct coupling is more efficient than thier own convertors. This is what they say happens as the torque convertor lock up engages.
Lee

Mycroft

The best manuals are nowhere near 100% and in many instances the auto'box is more efficient than any manual...

The object of a 7spd seq box is to try to make the box as efficient as possible, the revs are in the optimum band for as much time as possible and the change time is minimal... yet it is a fact that still at times these boxes are not as efficient as an auto'box. That answers the 'missing' bit, it was so blindingly obvious that I omitted it. Sorry

Level Tens' pages are simplified for the benefit of people like you...

trollhunter

Ok guys , ive got an idea , mycroft can tell me how to modify my gearbox/TC and i will report back if it is noticably quicker , if it is apologies will be in order, if not well whatever , of course to get the best mycroft would also have to tell me how to reset the MINES, if this has indeed lost its 'performance settings ' what is it running on ???? and could it make the car sluggish off the line ???, had a bit of a race with a kwak ZX9 today and really felt the effect mycroft is on about when he says the auto suits the turbo , so who knows he may be right about the TC bit , i am not clever enough to fully understand the teccy arguments can someone put it in laymans (troll type) terms .?????

logiclee

We are talking about the way transmitting power from the engine to the gearbox, ie- clutch or torque converter.
No one is suggesting the entire drivetrain of a manual car is 100% efficient.
But an auto more efficient than an equivalent manual, how?


A direct link is as near 100% as you can get.
Thats why torque converters have a lock up facility to make the power coupling as efficient as a direct link. At all other times the torque convertor introduces losses to the drive train making it less efficient.

Even Levelten tell you this.

Mycroft

Fuel efficiency... perhaps?

What efficiency are they talking about?

hahaha

Mycroft

Don't take this the wrong way mate, but you suffer the worst mis-nomer I have witnessed in some time... read things with the mind in gear... not in neutral.

logiclee

trollhunter,

Every car is set up as a compromise, if you want your car to be more performance biased there is no question that mods to the electronics and torque converter will make it faster and feel more responsive.

What it won't do is make it faster than it would be with a good driver and a close ratio manual box with a clutch.

It also won't double you torque and power or suddenly make you faster than Diablo's and Ferrari's.

Lee