Emira weight distribution

[GrahamClark_60-68]

Ok, to preface this noob of the century question I recall the following saying “Better to stay silent and be thought the fool than to speak and remove all doubt.” But after much thought and many Google searches that have come up naught, I’m throwing caution to the wind here.

On weight distribution of the Emira V6 wrt other mid engine cars I understand that the engine positioning which is pretty much over the rear axle rather than more forward of the rear axle puts the car more in the category of “mid-rear” engine rather than “true” mid engine. A quick glance at the specs of the Espirit V8 and Ferrari 308 as a comparison surprisingly (at least to me) shows only slightly more mid bias (2-3%) than the Emira, I’m guessing attributed to the lighter power plant on the Emira. And I do appreciate the extra space I get behind the seats as a result as opposed to these other cars with the seats right up against the firewall.

But…. I’ve always been baffled by the left to right bias of the engine on the Evora and Emira (biased to the right looking from rear of the car). If I didn’t know its origins were British I could chalk it up to the driver being on the left and no passenger (i.e., better balance on the track and for solo driving). But of course for those of you driving on the wrong side of the car and road that would be double trouble (driver and engine on the same side of the car).

I also thought that maybe I was just looking at the supercharger cover and maybe it was offset to the right somehow and the engine itself was actually centered left to right but in the many assembly pictures I’ve seen that doesn’t seem to be the case and it does appear the engine itself is more to the right of the car.

So with this said, yes I’m out of ideas. Can someone help me out with my insanity?

 

[jp129]

This is what my US V6M with a full fuel tank and no driver looks like on the scales

 

[FlyNavy01]

The Emira's transverse engine configuration means the heavy transmission bell housing is to the left of the engine (behind the driver in left hand drive countries). This requires the engine to be offset to the right, and effectively counters any left/right weight bias that you're speaking of. The only "less than ideal" weight distribution is the 39/61 front rear, which matches that of modern Porsche 911's.

 

[GrahamClark_60-68]

The Emira's transverse engine configuration means the heavy transmission bell housing is to the left of the engine (behind the driver in left hand drive countries). This requires the engine to be offset to the right, and effectively counters any left/right weight bias that you're speaking of. The only "less than ideal" weight distribution is the 39/61 front rear, which matches that of modern Porsche 911's.

Ok, so after I wrote my rant (sometimes putting into words gets the brain working more) I thought about the trans. But it wasn't obvious to me that the trans is that heavy relative to the engine that it could provide that much counter balance. But I guess it does make sense now thinking about it. And the post from @jp129 seems to prove this out, given the "Left" measurement. Thanks. Sorry for the interruption, now back to your normally scheduled program........

 

[crestima]

Ok, so after I wrote my rant (sometimes putting into words gets the brain working more) I thought about the trans. But it wasn't obvious to me that the trans is that heavy relative to the engine that it could provide that much counter balance. But I guess it does make sense now thinking about it. And the post from @jp129 seems to prove this out, given the "Left" measurement. Thanks. Sorry for the interruption, now back to your normally scheduled program........

Hey, not a rant at all. This brief post exchange was actually informative and interesting, from my perspective.

 

[GrahamClark_60-68]

Hey, not a rant at all. This brief post exchange was actually informative and interesting, from my perspective.

Thanks for that support! It actually got me thinking about other transverse mid engine cars that I know of and looking for pics. First one was the V6 Fiero (yes, it seems slightly to the right). Next was the massive V12 in the Miura. Just CRAZY that this engine is transverse, but yes, from the pics I've managed to find, it does seem that it's very slightly to the right, but not nearly as pronounced as the Emira. Must be a very compact trans design indeed.

 

[freefall_junkie]

Transverse V12? That's nothing I've posted a pic of this before but it is so mad I just love it. I give you the Cizeta Moroder with a transverse V16. 80s Italian excess at its finest!

 

[Neily]

This is what my US V6M with a full fuel tank and no driver looks like on the scales
View attachment 67600

Hey, maybe I am thick, but I am having trouble deciphering your E-Z Weigh scale values. Please illuminate.

 

[jp129]

Hey, maybe I am thick, but I am having trouble deciphering your E-Z Weigh scale values. Please illuminate.

LEFT: References the left weight percentage - with a 50% value it means that right and left sides of the vehicle weight percentage is exactly the same (50/50); 1628 is the actual left weight in LBS.

FRONT: References the front weight percentage - with 38.9% front weight distribution; 1269 is the actual weight in LBS.

REAR: References the rear weight percentage - 61.1% rear weight distribution; 1990 is the actual weight in LBS

CROSS: References the cross weight percentage (LR + RF/Total) - 49.9% indicates the factory did a great job with a factory corner balancing job.

 

[seriously]

It’s still an approximation for weight distribution as measured by weight over the wheels.

When the car is in motion the polar moment of inertia is most important to how the car feels when it turns. I don’t think there is really a machine to measure this. This is more than front or rear wheel weight and also involves how high or low the weight sits in the car. That’s why many electric cars or hybrids although heavy feel oddly planted because the battery skateboard design brings most of the weight really close to the ground.

 

[bshads]

For reference, here's what my v6 Emira balanced out to with driver weight (190 lbs) and a half tank of fuel. You can see that the left side is still supporting more weight than the right, so in theory, removing more weight from the left side of the car (lightweight battery, driver seat, or a driver diet) would be more beneficial for ultimately balancing the amount of weight on each tire if you were seeking ultimate balance.

 

[NJemira85]

The Emira's transverse engine configuration means the heavy transmission bell housing is to the left of the engine (behind the driver in left hand drive countries). This requires the engine to be offset to the right, and effectively counters any left/right weight bias that you're speaking of. The only "less than ideal" weight distribution is the 39/61 front rear, which matches that of modern Porsche 911's.

before owning an emira, I didn’t realize it was nearly rear engine. This surprises me, having owned a 991.2 911 c4s 7mt, bc the 911 engine is literally in the ass of the car.

Do the evora and Emira have similar weight distribution?

I suppose in a perfect world, the removal of evora “rear seats” would have enabled some improvement for Emira.

 

[me73]

before owning an emira, I didn’t realize it was nearly rear engine. This surprises me, having owned a 991.2 911 c4s 7mt, bc the 911 engine is literally in the ass of the car.

Do the evora and Emira have similar weight distribution?

I suppose in a perfect world, the removal of evora “rear seats” would have enabled some improvement for Emira.

There's a big difference in the dynamics of a car with the engine behind the axle vs in front of it, even if the cars have similar weight distribution on the tires. The polar moment of inertia on a 911 will encourage the tail to swing out. The weight outside the wheelbase serves to destabilize the car. The weight inside the wheelbase of the Evora, Elise, and Emira (which all have about the same weight distribution) will be less sensitive. Still sensitive, as in any mid-engined car, but less than a rear engined car.

 

[NJemira85]

There's a big difference in the dynamics of a car with the engine behind the axle vs in front of it, even if the cars have similar weight distribution on the tires. The polar moment of inertia on a 911 will encourage the tail to swing out, the weight inside the wheelbase of the Evora, Elise, and Emira (which all have about the same weight distribution) will be less sensitive. Still sensitive, as in any mid-engined car, but less than a rear engined car.

Thank you for this.

This makes sense intrinsically, the “length of the pendulum” for 911 is longer, etc.

It also squares with how the emira chassis feels to drive, in the short time I’ve had it. More like McLaren / Ferrari balance than 911 balance in terms of my lizard brain physics sensors

 

[me73]

Thank you for this.

This makes sense intrinsically, the “length of the pendulum” for 911 is longer, etc.

It also squares with how the emira chassis feels to drive, in the short time I’ve had it. More like McLaren / Ferrari balance than 911 balance in terms of my lizard brain physics sensors

911s have a feeling like the back end of the car is still turning a beat after you feel like you're done with the corner. That's the best way I can describe it. The Emira and the other Lotus don't do that at all.

 

[seriously]

before owning an emira, I didn’t realize it was nearly rear engine. This surprises me, having owned a 991.2 911 c4s 7mt, bc the 911 engine is literally in the ass of the car.

Do the evora and Emira have similar weight distribution?

I suppose in a perfect world, the removal of evora “rear seats” would have enabled some improvement for Emira.

Yeah I would have preferred moving the engine forward and increasing the size of the trunk. Better weight distribution. Probably lose some storage space overall. But now that I know how hot the trunk gets it is actually useful to have some storage in the cabin.

 

[NJemira85]

Yeah I would have preferred moving the engine forward and increasing the size of the trunk. Better weight distribution. Probably lose some storage space overall. But now that I know how hot the trunk gets it is actually useful to have some storage in the cabin.

The trunk gets laughably hot. I told my wife to forget the trunk exists.

It also reeks of epoxy. Brings back memories of working in the shop with my dad

 

[KAR120C]

Moving the engine forward in any significant way would have moved the rear rear wheels forward. To make the trunk larger would have made the rear overhang larger and the car would look goofy. And the trunk is already fairly useless on a trip because it becomes incredibly hot.

Perfect weight distribution would be nice, I guess, but 40/60 is just fine and the engineers have accounted for it in suspension and wheel/tire size.

 

[me73]

Unless Lotus changes the engine/transmission to something that isn't FWD based, the weight distribution won't change. The relative position between the drivetrain and the axle is set. Porsche achieves a 45/55 wt distribution by longitudinally mounting the engine so it can sit further away from the axle line. I've owned both cars and IMO, it's not significant enough to worry about, at least in street and occasional track use.

 

[seriously]

Interesting. I didn’t realize the position of the engine relative to the rear axel was fixed. I assumed you could move the engine forward without moving the rear axel but that they didn’t to save engineering costs. Sounds like there is an engineering constraint.