Entry Level Luxury Performance Sedans

Replying to: blueguydotcom (Apr 11, 2008 7:09 am)

"Drop the heavy stuff - sunroof, 19 inch wheels, power seats, insulation, worthless gizmos (self drying brakes, dual hvac, auto windshield wipers) and finally ditch the metal fenders for plastics.Maybe they can get 150-200 lbs out of the car."
 
I heartily concur.
 
"Finally, ditch the inline 6 for a twin turbo 4, and lose another 200-300 lbs. Ah, now you've got a fun sedan at 3100 lbs."
 
Oops, ya lost me there. Why? Well, several reasons actually:
 
1) I'm a fan of smooth engines. The I6 that BMW uses is an engine type that is naturally in perfect balance, meanwhile, I4 engines are natural shakers with considerable second order (i.e. twice per revolution) vibrations. Granted, these vibrations can be counteracted with the use of balance shafts, however, said shafts add needless weight and complexity to the engine.
 
2) like I said, I'm a fan of smooth engines, and in the world of four-stroke engines, unless an engine has at least five cylinders, it becomes a "push-me-pull-you" affair with the engine driving the flywheel and drive train during the power stroke of any one cylinder, and then the drivetrain and flywheel driving the engine between each power stroke. With BMWs I6 engine, not only do you get an engine that is in perfect mechanical balance, but you get one that is always supplying power to the flywheel and drivetrain.
 
3) While I don't have the actual weights, I'm thinking that the composite metal blocked engine of the 3.0 liter engine in the E90 325i, 328i, and 330i is rather lighter than say Audi's iron blocked 2.0T. With the I6 engine design, all that is needed for vibration free engine is a block, a crank, and six piston/rod assemblies, With a high specific output blown I4, you typically have to cast the block out of lamellar graphite cast iron (GJL). Once you have the block, in addition to the crank and four piston/rod assemblies, you need to add two balance shafts (and the associated drive mechanisms), a turbocharger or two (and necessary plumbing and intercoolers and such), and a heavy flywheel that can help smooth out the torque reversals from the intermittent application of power.
 
All-in-all, I'm thinking that I'd MUCH rather have a naturally aspirated I6 than a blown I4.
 
Best Regards,
Shipo

Replies to this message:
• sls002 (Apr 12, 2008 7:26 am)
  • shipo (Apr 12, 2008 1:18 pm)
    • sls002 (Apr 14, 2008 7:36 am) and 17 more...

My sub 3000 pound 3 series coupe tomorrow after work. I bought a 1990 E30 325iA

Replies to this message:
• shipo (Apr 12, 2008 5:57 am)
  • kyfdx (Apr 12, 2008 6:37 am)

Replying to: nyccarguy (Apr 11, 2008 7:22 pm)

Nice job.
 
So, how difficult do you think it's going to be to delete the "A"?
 
Best Regards,
Shipo

Replies to this message:
• kyfdx (Apr 12, 2008 6:37 am)

Replying to: shipo (Apr 12, 2008 5:57 am)

Replying to: circlew (Apr 11, 2008 7:05 pm)

Replies to this message:
• circlew (Apr 12, 2008 7:41 am)

Replying to: shipo (Apr 11, 2008 7:07 pm)

Replies to this message:
• shipo (Apr 12, 2008 1:18 pm)
  • sls002 (Apr 14, 2008 7:36 am)
    • alltorque (Apr 14, 2008 8:01 am) and 16 more...

Replying to: fedlawman (Apr 12, 2008 7:21 am)

Replying to: sls002 (Apr 12, 2008 7:26 am)

Replies to this message:
• sls002 (Apr 14, 2008 7:36 am)
  • alltorque (Apr 14, 2008 8:01 am)
    • sls002 (Apr 14, 2008 8:36 am) and 15 more...

I actually first walked away from the car last Sunday after initially looking at it because it was an Automatic. A few voices in my head (roadburner & fedlawman) told me I was crazy. I'm actually going to learn to perform the maintenience on the car myself. Once I get it running well, then I'll swap out the slushbox for a 5-speed.

Replies to this message:
• fedlawman (Apr 13, 2008 7:58 pm)

Replying to: nyccarguy (Apr 13, 2008 6:00 pm)

What, it's an automatic?!?!
 
I missed that part of your original message. Never mind, you shouldn't have bought it.