A&Q about 350Z
Q:
I was looking at my Suaber C9 model, and it seems as though the powertrain is tilted. When you mount the engine and transmission, the rear part, the transmission is like lifted slightly upward. Here's a pic of what I mean
The blue is the engine, clutch, and transmission. Wouldn't placing the entire powertrain slightly titled make the rear suspension, rotors, subframe,etc, tilted instead of straight? Also wouldn't it make the powertrain higher at the rear? Because I thought the lower the powertrain the better, hence the reason why the Gallardo's gear box hangs out at the rear of the car. Are there any advantages of placing the powertrain titled instead of straight?
A:
You said it... lower CG. The rear suspension is independent of the engine/tranny, so it wouldn't matter if the engine stuck straight up in the air.
The engine weighs more than the tranny. Tilting it down puts more weight lower.
A:
oo, so do any other cars have tilted powertrains, or was it just the Group C cars? Also which set-up is better for racing, the tilted powertrain with the slightly lifted gearbox, or the straight powertrain with the hanging gearbox?
A:
lots of front engine RWD cars have a tilted power train, usualy because the rear axle is lower than the crankshaft.
Lots of FWD's have them as well, it lowers the profile of the engine and brings some of the weight towards the centre of the car.
And I think we all know that a straight power train, with the gear box hanging out the back is better.
It lets the coriolis force lines connect with the centrifugal lines generated by the corning forces, which of course makes the car super duper faster.
A:
most bmw straight engines sit at a sideways longitudinal angle. it's not uncommon.
A:
Thier extra special, they are Bitilts, they tilt both ways.
Kind of like Curtis does when he's drunk.
A:
That implies that I've been drunk before... which applies right now
I swear it was my first beer ever. I'll never drink again. Promise.
A:
hehe I'm a straight egde too
The straight powertrain with the gearbox hanging out at the back performs better, and looks better, like in the Gallardo
Now thats what I call low CG
A:
it's good, right up to the point where you hit a bump in the road. the lambo garage near my dad's office had one in for repair, a guy hit a bump fast enough to crack and/or spit the rear gearbox casing./
A:
ouch, then Lambo should give it an undertray instead of leaving it out in the open
, but it does look good though
A:
how so? every BMW i've seen with the engine mounted that way (every BMW with a straight engine instead of a vee.) if your looking for the back towards the front they lean to the right-hand side.
A:
You will find that they are angled backwards as well as to the side, its very uncommon for a RWD car to have the engines crank on the same level as the rear axle. Its usualy a little bit higher.
Tilting it back also helps with weight distribution of course.
A:
but the Gallardo's engine crank is at level with the rear axle right?
A:
oh, i get what you mean. i thought you meant the cylinder head leaned to one side but the bottom-end leaned to the other.
A:
probably not. since the drive output is nearer to the block, and part of the transmission is rearward of the drive outputs.
look at the pic below, see how the crank drives the upper transmission parts, then the output for the driveshafts is lower.