How Much Does this Matter? (Engine Mounting)

This is a picture of my 2009 Genesis Coupe's engine bay. I've marked the wheel centerline with the tape, and it is pretty much dead aligned with the middle of the number 3 cylinder. And yes, this car has a lot of caster.

It's so far forward partly because of this space.

That's about a 10 inch space between the firewall and the back of the cylinder head. 

So my question is how big a deal is this for handling? Is it a big enough deal that mounting a V8 lower and farther back, like the picture below, might actually make the car handle better? I ask because it looks like the centerline of the LS swap below actually is about even with the number 1 cylinder or maybe between the 1 and 2, and it's lower in the chassis.

It would probably improve it a lot to move the mass rearward and more within the wheelbase. Big project though!

TurnerX19 said:

It would probably improve it a lot to move the mass rearward and more within the wheelbase. Big project though!

Hahaha, just exhaust, hoses, mounts, shifter, drive shaft, extending the wiring harness and figuring out a completely different oil pan and pickup!

In reply to DaewooOfDeath :

Wire harness would probably reach, so not that bad is it?

As a newbie driver I like the slower-to-react nature of a car with a higher polar moment of inertia so as long as the front to rear weight balance was maintained I'd rather keep the engine sticking forward a bit.

I'd estimate It matters about 1.6% on your overall weight distribution.

Moves about 50lbs off the front axle to the rear.  Moving That large up high battery to the bottom of the trunk would probably net the same effect for WAY less effort.

Or the V8 Swap..  Definately the V8 swap.

DaewooOfDeath said:

TurnerX19 said:

It would probably improve it a lot to move the mass rearward and more within the wheelbase. Big project though!

Hahaha, just exhaust, hoses, mounts, shifter, drive shaft, extending the wiring harness and figuring out a completely different oil pan and pickup!

Don't forget about the steering shaft either. If you look under the hood of the BRZ the engine is way farther forward than it needs to be and the only thing I can think of is to keep an extra U-Joint out of the steering shaft.

Does weight distribution matter when all you can do is burnouts? 

In reply to nocones :

I'm old school.  If V8 is an option, it's the only option. 

I think that photo is somewhat deceptive. Comparing to the front edge of the battery box, the front (timing cover) of the LS looks at most just a few inches rearward of that on the existing engine, and maybe not even that. Even with the added length of engine extending further rearward, it certainly isn't moving the powertrain center of (greater) mass anywhere near 10 inches. Consider also that the not-pictured (and not weightless) LS accessories basically mount in front of the engine vs their current location next to it. So it's a little lower and a little further back, but there's more of it and it's still forward of the overall vehicle CoG. Might end up being a wash. With equally well tuned suspensions, also likely not as helpful to handling as one might hope... But that's no reason not to do it anyway!

I'd wager moving the battery to the trunk might actually have the larger effect.

FWIW, in Herb Adams (who helped design the cars) book on tuning 2nd gen F-body cars, he found that moving the battery to the trunk was equivalent to moving the engine back 6". 

And that's a big, cast-iron lump.

I'd say it's a fairly big deal.

nocones said:

I'd estimate It matters about 1.6% on your overall weight distribution.

Moves about 50lbs off the front axle to the rear.  Moving That large up high battery to the bottom of the trunk would probably net the same effect for WAY less effort.

 

Or the V8 Swap..  Definately the V8 swap.

Is this you being good at modeling or you being good at using some sort of program? Either way, I would like to learn this Kung Fu.

Driven5 said:

I think that photo is somewhat deceptive. Comparing to the front edge of the battery box, the front (timing cover) of the LS looks at most just a few inches rearward of that on the existing engine, and maybe not even that. Even with the added length of engine extending further rearward, it certainly isn't moving the powertrain center of (greater) mass anywhere near 10 inches. Consider also that the not-pictured (and not weightless) LS accessories basically mount in front of the engine vs their current location next to it. So it's a little lower and a little further back, but there's more of it and it's still forward of the overall vehicle CoG. Might end up being a wash. With equally well tuned suspensions, also likely not as helpful to handling as one might hope... But that's no reason not to do it anyway!

I'd wager moving the battery to the trunk might actually have the larger effect.

I think you're right about the battery thing being a bigger factor.

Here's a better picture btw. 

DaewooOfDeath said:

nocones said:

I'd estimate It matters about 1.6% on your overall weight distribution.

Moves about 50lbs off the front axle to the rear.  Moving That large up high battery to the bottom of the trunk would probably net the same effect for WAY less effort.

 

Or the V8 Swap..  Definately the V8 swap.

Is this you being good at modeling or you being good at using some sort of program? Either way, I would like to learn this Kung Fu.

This is very likely Nocones being good at making a simple model. The fact is the entire car and it components can be summed up by location and mass to generate a very good estimate of the center of gravity location (in 3 axes). Some of the testing rigs I have used produce similar results by rolling/pitching/yawing a car and determining the CG location for various changes. One item that I recall specifically was moving the ignition box from the dash to the floor and yielding a CG height change of ~1mm for a 3kg part being moved vertically ~500mm.

Moving the battery from front to rear is a pretty significant change in CG in the longitudinal axis. This is mostly because the entire mass moves a long way. For the engine, even moving the same mass aft 6" will result in the CG moving significantly less than the actual move (because it is a fraction of the total vehicle mass).

Ok. That does sit back a little further than I was seeing, but the accessory drive belts are pretty close to the same place on both. So what looks like pure 'added lightness' in front of the cylinder heads will still have an alternator, PS pump, and (if street car) A/C condensor, in addition to that water pump already hanging out there.