Audi TT RS Teasers

[MadCat360]

So being lighter isn't better?

It is if you're talking about a race car. But this is a sports car. A sports car is about a fun drive, not being fast. A Miata is a great drive, but it's not fast. At the other end, a Radical is very fast and exciting, but it doesn't have fun handling (it has race car handling, which is safe and controllable and easy, if you know how to drive at least).

If you remove the weight at the front, it changes the weight balance. Changing the weight balance is always going to change the handling outright no matter what else you change on the car, but it also has the opportunity to change it more due to the fact that the manufacturer will have to change the suspension's high speed and low speed bump, spring rates, spring tension, rebound, gas pressure, ride height and shock length. They'll also have to change roll bars, brake bias, differential ratios and front/back torque split... we're talking about a complete reset and makeover of the entire car's handling.

Could it turn out to be better? Yes. Could it turn out worse? Yes, and certainly if they just bang the engine in there and don't make any changes.

It will come out the other end faster, though, no question about it. But why are you looking at an Audi TT for a fast car? Excitement is fast, handling is fun. Sports cars are supposed to be fun. So basically, everything that makes a TT fun is getting changed, and that's always worrying.

On the engine: there is no reason why the V6 couldn't have been made better. Besides, if they'd have turbocharged it it would have made the same or better HP/torque figures I'm sure.

 

[fbc]

^ I'm sure Audi will tune the suspension well to take into the account the reduced weight.

Less weight is always better (leaving aside extreme examples like yours of the Radical).

 

[MadCat360]

Less weight is always better (leaving aside extreme examples like yours of the Radical).

Less weight means the suspension needs to be harder.

And I know Audi will tune it, they'd be stupid if they didn't. But even if they tune it right, the weight distribution will always be different and that will always have an effect on the handling no matter what suspension setting you have.

EDIT: Okay, another example: Mustang. Heavy car. Great handling. The soft suspension means you can throw it into corners and that is fun. It is also accommodating of average drivers.

 

[fbc]

And I know Audi will tune it, they'd be stupid if they didn't. But even if they tune it right, the weight distribution will always be different and that will always have an effect on the handling no matter what suspension setting you have.

Using essentially a front-wheel drive platform, reducing the engine weight will improve the TT's weight distribution. Figures I can find indicate the TT currently runs around a 60/40 front/rear weight split, so reducing the weight up front will only help matters.

Less weight means the suspension has to deal with, and control, less mass & inertia, so it's better able to do it's job.

 

[Suedschleife]

Less weight means the suspension needs to be harder...

That is news to me. With everything else being the same, lower weight means lower spring rates.

I agree that certain weight saving can be bad for handling, but I have yet to see this happen when removing weight at the front of a front heavy car.

 

[MadCat360]

That is news to me. With everything else being the same, lower weight means lower spring rates.

Yes. Which means harder bump/rebound settings to keep the suspension from bottoming at speed and hard cornering. The result is a firmer ride for driver/passenger.

 

[the Interceptor]

Well, very heavy cars are known for ironing out bumps and creases in the road. Question is how much of that is down to the weight, and how much to the capabilities of the engineers setting it up.

Other than that:

Less weight is always better

QFT

Shedding weight in a car is good in every way, shape and form. Sure you can unbalance the car inadvertently by removing too much at one end, but I guess a manufacturer like Audi will be on top of that.

I have piloted a lot of different cars, and despite the fact that actual cornering speeds didn't have much to do with weight, the lighter cars always were much more fun to drive overall.

Yes. Which means harder bump/rebound settings to keep the suspension from bottoming at speed and hard cornering. The result is a firmer ride for driver/passenger.

You sure? I would assume that a light car on a soft suspension will lean just as much as a heavy car on a hard suspension, because the lighter bodywork will produce less mass inertia and centrifugal force.

 

[Dogbert]

EDIT: Okay, another example: Mustang. Heavy car. Great handling. The soft suspension means you can throw it into corners and that is fun. It is also accommodating of average drivers.

wut

Yeah, I mean, who doesn't like body roll and chassis flex?

 

[Suedschleife]

You sure? I would assume that a light car on a soft suspension will lean just as much as a heavy car on a hard suspension, because the lighter bodywork will produce less mass inertia and centrifugal force.

I found this ("Ride comfort" to "Ratio of Sprung to Unsprung Weight" in particular) a very interesting read. Explains how lightweight cars are inherently more affected by bumps.

However, I still couldn't find any need for increased damping in any literature on the subject, rather the opposite as reduced spring rates result in less energy during rebound.

 

[otispunkmeyer]

Ever heard of the car that made Audi famous? Of course 5 cylinders is Audi.

I love it. Bit expensive, but who cares, with that sound, and that torque.

EDIT: Also: VW? I don't recall them ever making an I-5...

yeah i think they did.... but it was called a V5... it had a supremely shallow angle, like 15 degrees or something. so it effectively was just an I5... it was 2.3l i believe and is kinda thirsty

 

[ahpadt]

EDIT: Okay, another example: Mustang. Heavy car. Great handling. The soft suspension means you can throw it into corners and that is fun. It is also accommodating of average drivers.

WHAT?

 

[prizrak]

Yes. Which means harder bump/rebound settings to keep the suspension from bottoming at speed and hard cornering. The result is a firmer ride for driver/passenger.

I highly suspect that difference in weight between a V6 turbo and an I5 turbo would be very low especially considering that modern engines are mostly aluminum.

The 2.0TFSI (I4) TTS coupe is 3252lbs so the RS is not likely to be a bit under 3400. This is about how much my car weighs and I have a pretty nice ride.

Also keep in mind that the article Suedschleife posted has to do with ultra low weight vehicles something like Exige/Elise or a Radical.

 

[MadCat360]

You sure? I would assume that a light car on a soft suspension will lean just as much as a heavy car on a hard suspension, because the lighter bodywork will produce less mass inertia and centrifugal force.

The purpose of dampers is to stop undulations over bumps. In ye olde car, hitting a bump with any kind of speed caused the springs to bounce back and you get a body which will bounce up and down and side to side for some period before it would finally settle down. I'm sure we've all seen the old footage of early Fords going over rough pavement? The effect got better with the implementation of anti droop, but it was still a huge issue at speed.

So a damper, by taking that undulating force and dumping it into the air stream as heat via oil, takes away the undulations. The general rule is, the softer the springs, the more undulation, the harder the dampers have to be to stop it, since the bump in the road will be able to push the spring faster and harder.

WHAT?

Yes. It's a very fun handling car and it's easy to read. It's just not fast.

 

[Suedschleife]

...The general rule is, the softer the springs, the more undulation, the harder the dampers have to be to stop it, since the bump in the road will be able to push the spring faster and harder...

True, but wouldn't lowering the unsprung weight have the same effect on undulation and additional advantages?

 

[Leonidae]

EDIT: Also: VW? I don't recall them ever making an I-5...

VW Transporters have i5 diesel, turbodiesel and gasoline.. Rabbit/Golf MkV has same 2.5l i5 as well in the US.. do I need to go on?

 

[MadCat360]

True, but wouldn't lowering the unsprung weight have the same effect on undulation and additional advantages?

If you didn't change the spring rates, yes. But then it would be even more uncomfortable.

 

[klankymen]

VW Transporters have i5 diesel, turbodiesel and gasoline.. Rabbit/Golf MkV has same 2.5l i5 as well in the US.. do I need to go on?

Ah, wasn't thinking about vans, yes, of course. But I've never seen a golf with an I5

 

[JCTK]

what the stuff was that "pro" who sounds like an .... talking about when saying the lighter I5 engine would ruin the handling compare to putting in a V6~?

please go get some very basic facts sorted first before trying to sound like a professional of sort with the suspension stuff...
"oh no the front of the TT would be lighter so it must handle worse"

 

[Cold Fussion]

what the stuff was that "pro" who sounds like an .... talking about when saying the lighter I5 engine would ruin the handling compare to putting in a V6~?

please go get some very basic facts sorted first before trying to sound like a professional of sort with the suspension stuff...
"oh no the front of the TT would be lighter so it must handle worse"

I think its easier to understand Madcat if you take your physics text book and just burn it.

 

[MadCat360]

what the stuff was that "pro" who sounds like an .... talking about when saying the lighter I5 engine would ruin the handling compare to putting in a V6~?

please go get some very basic facts sorted first before trying to sound like a professional of sort with the suspension stuff...
"oh no the front of the TT would be lighter so it must handle worse"

I didn't say the TT would be worse. The lightness discussion was not aimed at the TT. Someone said lighter is better and I said to a point because suspension needs to be harder. I did not say the TT would be uncomfortable. My beef, pertaining to the TT is the opportunity for Audi to ruin it by having to correct for weight. No manufacturer gets it right all the time.

I don't think you understand how much difference a tiny little change can make.

Again I sate, the difference between handling and cornering ability is oversteer/understeer/turn in/lean and G-forces. No one seems to get that.

I think its easier to understand Madcat if you take your physics text book and just burn it.

So the setup techniques I learned in racing school and from mechanics and crew chiefs who I talk to on a regular basis is wrong, right? Yeah I know nothing.

How about this, how about you use your physics textbook and explain how I'm wrong intelligently (which you must be able to do since you read so many books and are such an academic), rather than making vague accusations?