335xi faster than 335i?

[YYZATC]

The 0-100 km/hr times provided on bmw.ca show the 328i coupe as 6.6s and the 328xi coupe as 7.1s while the 335i coupe is 5.6s and the 335xi coupe as 5.5s. Can someone tell me why the xi version is faster in the 335 and not in the 328? Thanks.

[aus]

www.e90post.com

[BForbes]

Three letters for ya. AWD. You will have higher traction with the AWD vehicle.

[larryn]

Originally Posted by onehots2k

Three letters for ya. AWD. You will have higher traction with the AWD vehicle.

The OP is saying if the 335xi is quicker than the 335i, why isn't the 328xi faster than the 328i.

I also agree with aus, and would recommend asking that question at e90post, since no 1er exists with all wheel drive, and you are asking about 3 series cars. I'd also suggest not just checking 0-60 times, and rather research what transmissions and differentials are used, and seeing if there are gearing differences.

[BMWeber]

I've been driving a E46 M3 as a daily driver for the last 3 months and today I was driving a 335xi coupe. while not having the top end rush of the M3 I bet off the line I would pull an immediate 1-2 care lengths with how hard I could launch that car.

[TunedM2C]

Originally Posted by aus

www.e90post.com

+1

[mateo]

...X-Drive FTMFW


:roundel:

[NJKSC27]

drove a 335xi and is very fast and very "stuck" to the pavement.

[Propagator]

AWD gives you a much better launch, and therefore a better 0-60 time. (if traction at the launch is a limiting factor) But it also introduces more weight and drivetrain loss, which shows up as lower trap speed.

As for the 328i being faster than the 328xi, it's probably because lauching a 3300lbs car with a naturally aspirated motor making 200ft-lbs of torque is really not traction limited. But once you get to the 300ft-lbs 335i, it's a different story.

AWD is always a good companion for the non-linear and somewhat unpredictable/explosive power delivery of traditional turbos. Now the 335i is all fancy with supposedly NA V8 like power delivery, so adding the heavy and complicated X-drive may not be very necessary.

[Nixon]

It's all about putting power to the ground at launch. AWD only becomes a launch advantage when engine output is high, and burns off tires extremely easily. With lower power output engines, AWD is nothing but a drag on the drivetrain and added weight.

It isn't a gearing difference. The 335i and 335xi have the exact same transmission and final drive ratios. Final drive is 3.08:1 on manuals, and 3.46:1 for autos. And the 328xi has the final drive advantage over the 328i, in both auto and manuals. So the gearing advantage should make the 328xi quicker, but it doesn't.

AWD doesn't give any advantage in the NA engines because it just isn't a huge tire-burner the same way the twin-turbo engine is. So there is no need to have AWD tame the tire-spinning in order to get power to the ground.

Launch styles for manual transmission AWD cars are really different once you get enough low-rpm torque to spin all 4 wheels for a moment at lauch. You can load the engine a bit, then drop the clutch. Then bam! You take off like a rocket after just a little bit of spin. Try this same launch on a 328xi and the engine will bog. You have to launch with lower RPM and slip the clutch.

Try this same launch with a 1-wheel drive 335i, and you just get smoke (or power to the engine is cut by traction control and the engine bogs). Again, you have to launch with lower RPM and slip the clutch.

It's all about the launch with all that low-rpm torque in the twin-turbo engine. AWD and tons of low-rpm torque are a magical combination. That's the only reason why the numbers come out the way they do.



328i:
Unlaiden weight: 3340 [3406] lbs
Manual gear ratios – I/II 4.32/2.46 :1
Manual gear ratios – Final drive ratio 3.23 :1
Automatic gear ratios – I/II 4.07/2.37 :1
Automatic gear ratios – Final drive ratio 3.73 :1
Acceleration 0-60 mph – Manual transmission 6.3 sec
Acceleration 0-60 mph – Automatic transmission 6.9 sec

328xi:
Unlaiden weight: 3582 [3627] lbs
Manual gear ratios – I/II 4.32/2.46 :1
Manual gear ratios – Final drive ratio 3.38 :1
Automatic gear ratios – I/II 4.07/2.37 :1
Automatic gear ratios – Final drive ratio 3.91 :1
Acceleration 0-60 mph – Manual transmission 6.9 sec
Acceleration 0-60 mph – Automatic transmission 7.1sec

[Nixon]

Or, in other words, exactly what spinzero said while I was still composing my post....

grrrrr :biggrin:

[YYZATC]

Thanks for the info spinzero and nixon.

[aus]

This needs to be moved to OT.

[ichiban]

AWD has more powertrain loss than 2WD cars. from the get go the xi will be faster, but the regular i will gain in spd fairly quickly.

[Propagator]

Originally Posted by Nixon

Or, in other words, exactly what spinzero said while I was still composing my post....

grrrrr :biggrin:

Hah! I pity you and your well composed and overly informative post!

I win!

[Khobin~]

[BForbes]

We have so many smart fellas posting in this thread.

[Nixon]

Originally Posted by ichiban

AWD has more powertrain loss than 2WD cars. from the get go the xi will be faster, but the regular i will gain in spd fairly quickly.

I'm going to write a real quick response before spinzero aces me out again...

Yep. That's the problem of judging a car just on it's 0-60 speed. It doesn't tell the whole story. If we compared 0-30 times, the 335xi would look even faster compared to the 335i. Compare 0-100-0 times and the 335i wins. Compare 0-100 times on an ice track, and the 335xi wins. No matter how many tests a 335xi beats a 335i at, you can run another test where the 335i beats the 335xi.

I could come up with a definitive answer as to who wins if somebody loans me a 335i and a 335xi so I can do extensive long term tests.

(hint: The one "who wins" will be me...)