Audi S4 to have 3.0 V6- supercharged

[M_Bolc]

Read this on Car and Driver, sounds interesting:

2010 Audi S4 to Get Supercharged V6 - Car News
Audi maintains performance while increasing efficiency.

BY ALISA PRIDDLE
April 2008



Those who assumed the 2010 Audi S4 would share its powertrain with the S5 appear to be incorrect. Instead, look for an all-new forced-induction 3.0-liter V-6 that will generate something close to the 340 horsepower found in the outgoing S4’s 4.2-liter V-8.

Why is the Audi S4 moving from a V-8 to a V-6, just as the BMW M3 moved from an inline-six to a V-8? In two words: Fuel economy. Audi’s strategy is to deliver comparable or improved overall performance by toeing the line on weight and maintaining power output by using forced induction on a smaller displacement engine.

The new V-6 also will be the base offering in the A6 Quattro, replacing the 3.2-liter V-6. Known as TFSI, which in the past has been Audi’s internal moniker for four-cylinder turbos, the new engine may be referred to as the 3.0T in the model name, possibly indicating a twin-charged system using both a supercharger and a turbocharger. While Volkswagen has a “twincharger,” Audi has not yet offered such a system. At the very least, we expect the new V-6 to be supercharged.

Don’t look for a dramatically lower weight in this S4. Compared with the outgoing 2008 A4, the redesigned 2009 A4’s body is approximately 10 percent lighter. The A4 and S4 will use identical sheetmetal this time around—the new S4 apparently was not developed by Audi's high-performance division, Quattro GmbH, but the S4 will be distinguished by having distinct cladding from the A4. Not only does the sharing save money, but stresses the exclusivity of the RS 4 which will better stand out with its distinct sheetmetal—including bulging fenders—and a V-8.

A trick differential like the one in the BMW X6 adds about 40 pounds. We expect to see Audi roll out its Magna-sourced “sport differential” (BMW uses ZF) in the S5 and Q5 as well, to combat understeer in its four-wheel-drive vehicles.

The supercharger will make the V-6 weigh about the same as the V-8 overall. Add in the requisite safety and luxury features that every new model gets, and it’s a wash. Expect Audi to claim a nominal weight reduction of only 20–100 pounds for the new model, putting it at about 3900 pounds.

Audi will debut the 2010 S4 this fall sometime after the 2008 Paris show in October—making the L.A. show in November a possibility. Expect the new S4 to compete with the BMW 335i for efficiency but the Audi probably won’t have the edge in performance and will cost significantly more. Watch for more details on the new S4’s engine in the coming days.

[Labcoatguy]

A blown six as a "fuel saver"? Something isn't multiplying or adding right. Well, whatever forces their induction.

[edkwon]

Originally Posted by Labcoatguy

A blown six as a "fuel saver"? Something isn't multiplying or adding right. Well, whatever forces their induction.

Whats so hard to understand that a forced induction V6 on average will consume less fuel than an equivalent powered V8? Are you running on an assumption that said V6 engine is running on full boost all the time?

[bartboy9891]

Originally Posted by edkwon

Whats so hard to understand that a forced induction V6 on average will consume less fuel than an equivalent powered V8? Are you running on an assumption that said V6 engine is running on full boost all the time?

A lower number of cylinders doesn't necessarily mean better fuel economy. The transmission plays a big role, there is a reason why the C6 Corvette can potentially pull some relatively high mpg figures even though it has a 6.0L V8 and 400+ hp.

[edkwon]

Originally Posted by bartboy9891

A lower number of cylinders doesn't necessarily mean better fuel economy. The transmission plays a big role, there is a reason why the C6 Corvette can potentially pull some relatively high mpg figures even though it has a 6.0L V8 and 400+ hp.

Of course it doesnt guarantee anything, but he's reacting as if its impossible for a forced induction V6 to have better fuel economy than an equiv powered V8.

So let me ask you, assuming the older V8 S4 shares the same transmission as the newer supercharged V6 (maybe not, but lets take transmission out of this equation), then do you think its possible the V6 can generate better mpg numbers over combined city/freeway use?

[bartboy9891]

Originally Posted by edkwon

Of course it doesnt guarantee anything, but he's reacting as if its impossible for a forced induction V6 to have better fuel economy than an equiv powered V8.

So let me ask you, assuming the older V8 S4 shares the same transmission as the newer supercharged V6 (maybe not, but lets take transmission out of this equation), then do you think its possible the V6 can generate better mpg numbers over combined city/freeway use?

I'm not even close to an expert on this (or anything really), but sure I think it's possible. That's still simplifying the situation too much though.
Compare an SUV with a 3.0L inline 6 vs. a 4.8L V8 that puts out nearly 100hp more compared to the I6, which one do you expect to get significantly better mileage?

[Labcoatguy]

Originally Posted by edkwon

Whats so hard to understand that a forced induction V6 on average will consume less fuel than an equivalent powered V8? Are you running on an assumption that said V6 engine is running on full boost all the time?

It's the fact that it's a supercharger, rather than a turbo or two, that makes me wonder. Turbos can be off boost, but superchargers are continually coupled by that belt. Unless it has some clutch or other decoupling system, yes it will be on boost all the time, if not full boost; either way, it's gonna gulp. I can't think of a single past Audi that's been supercharged though, and considering their turbo expertise, it doesn't make sense why they'd suddenly change technologies.

[edkwon]

Originally Posted by Labcoatguy

It's the fact that it's a supercharger, rather than a turbo or two, that makes me wonder. Turbos can be off boost, but superchargers are continually coupled by that belt. Unless it has some clutch or other decoupling system, yes it will be on boost all the time, if not full boost; either way, it's gonna gulp. I can't think of a single past Audi that's been supercharged though, and considering their turbo expertise, it doesn't make sense why they'd suddenly change technologies.

Audi stated their rationale for making the switch was in part a vanity/image reason. Since they are the luxury brand of the VAG group they felt resorting to turbo technology on a FI S4 motor would result in turbo lag feel, taking away from the 'premium' feel of their cars, and since owners of the last couple gen S4s have been spoiled by the feel of the more instant-on torque of their V8 engines, they want to preserve that feel as much as possible with a lower displacement engine and hence adopting supercharger tech vs turbocharger. Thus saving the high hp V8 for the next gen RS4 model.

Im just repeating what Audi's press has said, i don't necessarily agree with this.

[prizrak]

They should have gone with a twin turbo system. I also don't see much efficiency gains since the supercharger will always run boost. Also I have to say my 1.8T gets pretty crappy mileage as soon as it starts boosting, pretty much just as bad as the V6 model. Oh well I'll just get the RS6 with it's twin turbo V10

[klutch]

Damn...well, lets assume similar economy figures, price and all that...the biggest drawback will be the lovely rumble the current S4 emits from its fine-ass.

[M_Bolc]

VWs twincharger system (1.4 in the Golf) was enginered for fuel economy and power, 170 bhp from a 1.4, and it does get good mileage. Maybe this S4 will be a twincharger?

[prizrak]

Originally Posted by M Bolaños

VWs twincharger system (1.4 in the Golf) was enginered for fuel economy and power, 170 bhp from a 1.4, and it does get good mileage. Maybe this S4 will be a twincharger?

/me Hates on the twin charger

[Wizegui]

As do I. It's way too jerky and unnecessary. Modern have evolved and often give very little lag. I think they should have gone with a light pressure turbo setup.

[Vette Boss]

I think this is just for people who think a V8 is unfriendly to the environment, mostly. It's really no better, adding a supercharger to a V6 still lowers the fuel economy.

You can have economy or performance, not really both at the same time.

[bartboy9891]

Originally Posted by Vette Boss

You can have economy or performance, not really both at the same time.

Shall I mention the Corvette one more time? As far as I can tell, tall gears + big torque is the reason.

[Vette Boss]

Originally Posted by bartboy9891

Shall I mention the Corvette one more time? As far as I can tell, tall gears + big torque is the reason.

The Corvette is an exception to the rule. One of the reasons it gets good economy is because it's quite light for what it is. You can cruise around in top gear all day, doing 1,500rpm.

[prizrak]

Originally Posted by bartboy9891

Shall I mention the Corvette one more time? As far as I can tell, tall gears + big torque is the reason.

Vette gets horrible mileage when driven aggressively. You can say the same thing about a turbo car, they tend to get decent mileage out of boost range but as soon as you boost it will be etrocious.

[jetsetter]

Auto Motor und Sport has published the first report to surface out of that engine symposium in Vienna this morning where Volkswagen AG powertrain czar Wolfgang Hatz presented on the new 3.0T FSI engine planned for the next-generation S4, A6 and likely Q5 and Q7 as well. Thanks Mike again for the tip. The AMundS link is below at the bottom, but here's a quick translation of their German text.

As expected at the Vienna Motor Symposium, Audi announced plans to introduce a new supercharged V6 engine. It is intended first for the refreshed A6 and also for the next-generation S4.

The previous S4 made us of a powerful 344-hp normally aspirated 4.2 V8. This new engine will be used in Europe and North America and will be good for 350 hp in the S4.

Despite similar levels of power to the old V8, the new V6 consumes significantly less fuel. It will be combined with a sports differential from Magna, which will also later be used in Q5 and S5 models.

The new Audi S4 is expected shortly after the A6 this autumn. For the A6, the new supercharged V6 engine will be implemented at the same time as a new facelift and will produce 290 hp and 310 lb-ft of torque in the A6 application.

We're monitoring all sources from Audi to try to get more information about today's presentation, but this information from Auto Motor und Sport is most interesting. 350hp is more than expected by about 20hp.

http://forums.motivemag.com/zerothread?id=3807920