Cars In General - Questions and Discussion

[YSSMAN]

I suppose it would make sense. Porsche is apparently working with VW on a DSG unit for the 911 and the like, and presumably that model would find its way into the R8 and Gallardo as well.

 

[1X83Z]

I suppose it would make sense. Porsche is apparently working with VW on a DSG unit for the 911 and the like, and presumably that model would find its way into the R8 and Gallardo as well.

The same Porsche dealer told me he believes that (the lack of DSG) is the sole reason why Carrera GTs won't sell.

I agree with him, for the record.

 

[land sea air]

Doesn't the Veyron have a 7 speed DSG? if they can make it work with that monster you would think the tech would trickle down to the 6 speed versions

 

[Alex.]

Oh good thanks sn00pie

I have a question:

*thinks of a question to ask*

What was porsche's original reason for slotting the engine behind the rear axel, when It could easily tuck just behind the front?

 

[land sea air]

I would say traction, but someone who knows for sure will probably post a more complete answer

 

[daan]

A Porsche dealer told me DSG can't be put in cars like that because it can't accomodate the torque.

Doesn't the Veyron have a 7 speed DSG? if they can make it work with that monster you would think the tech would trickle down to the 6 speed versions

The Veyron does indeed have a DSG gearbox.

http://www.bugatti-configurator.com/content/pdf/Veyron_en.pdf

EDIT:

I would say traction, but someone who knows for sure will probably post a more complete answer

I would say that was unlikely as the 911 came from the 356, which came from the VW Beetle.

This layout is typically chosen for three reasons, packaging, traction, and ease of manufacture:

* Since the engine is located at an extremity, the rest of the vehicle can be used for passengers and luggage
* Having the engine located over the driven wheels increase downward pressure which is helpful for grip on loose surfaces
* The drivetrain can be assembled as a unit and installed easily at the factory -easier than a FF layout where the driven wheels also steer the car

 

[///M-Spec]

Re: The DSG box.

It's important to remember the DSG in the Veyron has nothing to do with the unit found in a GTI or A3. They only share the name. The Audi/VW/SEAT/Skoda box is designed by BorgWarner and built under license by VAG, while the Veyron box was developed and manufactured by Ricardo Company.

I strongly suspect that Audi decided to keep Lamborghini's E-Gear system (which I'm pretty sure is a Magneti-Marelli box like the Ferrari "F1" boxes) for cost control reasons. Nothing that comes out of a Veyron is going to be cheap. Meanwhile, development continues on the beefier DSG systems that will handle more torque, but they probably just didn't make it in time to launch with the R8.

BTW, there are aftermarket upgrade kits for VAG's DSG boxes. Supposedly good for ~450 lb-ft of torque.


M

 

[Tornado]

If they are pulling 300 on the dyno, what does that mean at the crank? 330?

 

[guska]

Ok my question... What the hell is a DSG?

 

[Tornado]

A tranny with twin clutches. Makes for essentially non-existant upshift times.
Someone will probably offer a more complete answer, but that is the basic gist of it as I understand.

 

[///M-Spec]

Depends on how efficient you think the drivetrain is. If you use the popular 17% power loss for a modern RWD car, they are making closer to ~350 to the crank.

Hmmm... pretty much the 'rated' power of an LS1 Corvette. 💡


M

 

[land sea air]

Re: The DSG box.

It's important to remember the DSG in the Veyron has nothing to do with the unit found in a GTI or A3. They only share the name. The Audi/VW/SEAT/Skoda box is designed by BorgWarner and built under license by VAG, while the Veyron box was developed and manufactured by Ricardo Company.

I strongly suspect that Audi decided to keep Lamborghini's E-Gear system (which I'm pretty sure is a Magneti-Marelli box like the Ferrari "F1" boxes) for cost control reasons. Nothing that comes out of a Veyron is going to be cheap. Meanwhile, development continues on the beefier DSG systems that will handle more torque, but they probably just didn't make it in time to launch with the R8.

BTW, there are aftermarket upgrade kits for VAG's DSG boxes. Supposedly good for ~450 lb-ft of torque.


M

ok well that makes sense, I figured there must be a pretty good reason since the DSG is a good idea for pretty much any sports car. (or even any car in general) Lambos E-gear is in fact a Magneti Marelli attached to a six speed very similar to Ferrari's unit. I am very surprised that it's taking this long for VAG/Porsche to develop the DSG for higher powered cars since there are so many between the two companies.

 

[Jay]

Ok my question... What the hell is a DSG?

Twin clutch transmission that 1st,3rd,5th,7th on one shaft and its own clutch and 2nd,4th,6th on another shaft with its own clutch (well one shaft is hollow and the other gearshaft runs separately through the hollow shaft so then overall it doesn't take up much more room, and that is a potential weakness of it).

What happens is when you are in 1st gear the input shaft with 1st on it is engaged with the clutch, the computer preselects 2nd gear on the other shaft but the clutch is disengaged until you use the paddle to select 2nd then the first clutch disengages 1st and the second clutch starts to engage 2nd so it comes out as a near seamless shift (100ms or so). Then soon the computer will then pre-select 3rd on the other shaft (same shaft as 1st is located) in preparation for your shift.

Sorry if my explanation is alittle hard to follow, I'm sure there is some diagrams available with a google search.

 

[1X83Z]

The Veyron does indeed have a DSG gearbox.

 

[YSSMAN]

VW has been looking into replacing all of their slushboxes with DSG units in the future, and I'm certain it is an idea worth entertaining, however I can't see it working on every product. I'd love to be able to equip the DSG on "standard" Jetta and Rabbit, but that is a no-go thus far.

But hey, you can get DSG with the TDI. I like that idea. Especially when they bring us the 140 BHP model next year...

 

[1X83Z]

VW has been looking into replacing all of their slushboxes with DSG units in the future, and I'm certain it is an idea worth entertaining, however I can't see it working on every product.

Why not?

 

[nk4e]

This might be a a beginner's question or a plain stupid one but here goes: Why is there a filter on a Turbo?

 

[Jay]

This might be a a beginner's question or a plain stupid one but here goes: Why is there a filter on a Turbo?

Same reason there is a filter anywhere really, to stop large particals entering the turbo/engine and damaging it.

 

[nk4e]

Same reason there is a filter anywhere really, to stop large particals entering the turbo/engine and damaging it.

Well, it just seemed awkward for me to see that some sort of thing. Thanks though, I should be having more questions soon enough.

 

[Jay]

Well the turbocharger is apart of the engines intake tract so the filter could be fitted directly on the turbo or maybe in a filter box like factory does, so they have to put it anywhere before the turbo or MAF sensor (if fitted).

Sometimes you will see the turbo exposed for show or maybe a quick 1/4mile sprint but I doubt many people would leave it filterless on longer journeys.

 

[daan]

What do you wanna make those eyes at me for?

Explanations are always good, Doug. Correct me if I'm wrong, but don't just post a smiley.

 

[1X83Z]

Explanations are always good, Doug. Correct me if I'm wrong, but don't just post a smiley.

What - do you think they just pulled the DSG out of the TT for the Veyron? Everyone knows the Veyron's transmission was specially developed for the Veyron, as with all of the other things about it. The DSG can accomodate the torque in that vehicle because they spent hundreds of millions of dollars ensuring that it would.

 

[land sea air]

Did he say that? My original question was the only one that you could possibly take for anything resembling what you just said, its not like he was bending the truth by saying the Bugatti has a DSG, it does, even if its a different model than those used in otehr VAG products.

 

[daan]

What - do you think they just pulled the DSG out of the TT for the Veyron?

Did anyone state they did?

You said

A Porsche dealer told me DSG can't be put in cars like that because it can't accomodate the torque.

Note DSG, not VW's DSG, but DSG in general

Doesn't the Veyron have a 7 speed DSG?

The Veyron does indeed have a DSG gearbox.

http://www.bugatti-configurator.com/content/pdf/Veyron_en.pdf

But now you say.

The DSG can accomodate the torque in that vehicle because they spent hundreds of millions of dollars ensuring that it would.

So that means that DSG can handle the torque of a Carrera GT then? If it can handle the torque of a Veyron, it can handle a Carrera GT. You did not state a specific DSG. You made a general statement that DSG cannot handle torque, which has been proved wrong.

 

[TuneRVisioN]

What? I'm sorry. You must be new around here, so I have no idea if you're trying to be funny or taking a jab at the Americans. Every major automotive company has done it, be they American or not. In the '60s, we were very good at dong it, and did it in almost every major model made available.

...And it wasn't just power outputs either. In 1969, the Chevelle SS featured the first engine that had ever been advertised as smaller than it actually was. The 396 found in many of the SS models was indeed a 403 big-block, and indeed was making well-over the prescribed power outputs.



A lot of people say it, and I think a lot of the tests had noted it as well. I seem to recall a test of the Z/28 convertible in 2000 or 2001, equipped with a four-speed 4L60E, ran to 60 in a little over 5 seconds and topped out well over 150 MPH. By comparison to later SS 35th Anniversary models, which were rated at "just" 325 BHP, most of the coupe tests were about the same overall.

...It would lead one to think that early LS1 models were underrated just a bit, but like you, I've never really seen any solid performance figures. Dyno-tested models on shows like Horsepower TV have been putting down numbers in the 260s to the wheels, and assuming at least a 20 % loss at the crank, that would put the power numbers above 310 BHP.

Ohh... sorry for my stupidity. Just kidding. I still think its dumb to show the wrong HP for cars. It makes me sick. Atleast now I know why. 👍

 

[TuneRVisioN]

I have a question about automatic transmission. How come with some cars that drives in Automatic likes to go WAY past redline in any gear when pressing the gas lightly, (No downshifting is occurring, as I stay in the same gear past redline, it happens with all the gears sometimes.) while on the other hand when I floor it, (Which I usually am doing. ) It shifts at redline or a little before it? This is kind of ironic. Isn't it supposed to shift at a lower RPM if you lightly press the gas? And the harder you press it the higher the RPM's of the shift are? Yeah its kind of hard to explain...

 

[Jay]

That is odd, I have never experienced that, what car are we talking about? Hydraulic or electronic controlled auto?

 

[Tornado]

Its because automatic transmissions are set to shift at a certain throttle tolerance. If the tolerance isn't met, the transmission won't shift as early as if you floored it.



Now I have a question. What in hell does this bar along the back of Subaru Outbacks do?

After a full day of thought, all I can come up with is it allows Skitching to be performed easier, and that just seems socially irresponsible of Subaru.

 

[xXSilencerXx]

A lot of people say it, and I think a lot of the tests had noted it as well. I seem to recall a test of the Z/28 convertible in 2000 or 2001, equipped with a four-speed 4L60E, ran to 60 in a little over 5 seconds and topped out well over 150 MPH. By comparison to later SS 35th Anniversary models, which were rated at "just" 325 BHP, most of the coupe tests were about the same overall.

...It would lead one to think that early LS1 models were underrated just a bit, but like you, I've never really seen any solid performance figures. Dyno-tested models on shows like Horsepower TV have been putting down numbers in the 260s to the wheels, and assuming at least a 20 % loss at the crank, that would put the power numbers above 310 BHP.

That's interesting.

LS1.com dyno thread.


M

Thanks. That helped alot. 👍

 

[Jay]

Its because automatic transmissions are set to shift at a certain throttle tolerance. If the tolerance isn't met, the transmission won't shift as early as if you floored it.

Can you expand on that? that is pretty vague.

Hydraulic autotrans shifts on a set hydraulic pressure on the piston separate for each gear, the pressure derived from the governor on the output shaft (faster it spins the more pressure is given to the piston) and the throttle position valve, the further the valve is open (further open the throttle) the more pressure the governor requires to supply to the shifting piston to make it shift gears, delaying the shift.

But why wouldn't it shift early when the throttle is lightly pressed? Seems like the valve is sticking and wont close properly, maybe a change in fluid and filter (inside the trans) is needed. Maybe your kickdown cable is not connected? Many auto's require a vacuum line to the trans, is that still connected?. Or maybe a faulty governor?

I haven't come across this before but mostly I drive manuals, though I have come across a stock GM auto (hooked to a LS1) that wouldn't shift up when floored and continued on to hit rev limiter, just wouldn't shift until throttle was lifted slightly.

After a full day of thought, all I can come up with is it allows Skitching to be performed easier, and that just seems socially irresponsible of Subaru.

Easier for oldies to open the hatch? I know my late grandfather would have loved that.