Boot Mounted Battery

Started by Duk, September 28, 2010, 10:30:27 AM

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festy

15 years ago I had a cop try to write me a defect for my gtv's boot mounted battery, apparently that needs an engineers cert in nsw. I finally convinced him that was the factory location, so then he tried the same for the dellortos, he was sure they weren't standard equipment...

Duk

Ages ago I looked at moving the V6 engine towards the firewall, in the engine bay of my 75 to improve the 'handling' characteristics (IE: Improve turn in and mid corner grip).
Now I've read Fred Puhn's 'How To Make Your Car Handle', so knew how to calculate the effect of a single component's (like an engine or a battery) polar moment of inertia effect, on the car.

A long story short.
By removing the battery from the front a my 75, it would have more than 3 times the effect of moving the (MUCH) heavier engine back 1 inch.
The end result should(will) be much improved turn in and mid corner grip.

As an aside, reducing the mass of the front bumper should be even more effective than removing the battery, because the distance of a mass from the vehicle's (longitudinal) centre of gravity, has exponentially increasing effect. So the further from the longitudinal(front/rear) centre of gravity, the more effect a mass has.
It's the old 'lead tipped arrow' scenario. Mass at the front keeps the 'vehicle' going straight.
The heavier V6 engine PLUS the heavier impact absorbing front bumper bar's of the V6 cars causes them to understeer more than the lighter engined, lighter front bumper bar TS. Rather than the mass of the engine alone being the deciding difference in the handling characteristics between the 4 cylinder and the V6 75's..

It is also for this reason that quoting front to rear weight distribution tells VERY little of the car's 'true' characteristics.
Imagine adding 100Kg's to the front and 100Kg's to the rear of a car (any car). It's weight distribution would stay the same, but the car's polar moment of inertia would change dramatically. The car would now be even more reluctant to change direction (turn in) and if/when it could finally develop an oversteer situation (a rear slide) it would continue that slide more than it use to.  

shiny_car

Cheers Duk. *hope you didn't mind that I bumped your old thread*

I think I'll make relocating the battery a priority. It's odd that I never felt compelled to do so in my other cars, but it feels natural to do so in the 75! Come time, I'll discuss with a local engineer.

:)
Giulietta QV TCT . 1.75 TBi . Magnesio Grey - Black
GT . 3.2 V6 . Q2 . Kyalami Black - Red
75 . 3.0 V6 . Alfa Red - Grey

Duk

Quote from: shiny_car on June 08, 2012, 03:23:20 PM
Cheers Duk. *hope you didn't mind that I bumped your old thread*

I think I'll make relocating the battery a priority. It's odd that I never felt compelled to do so in my other cars, but it feels natural to do so in the 75! Come time, I'll discuss with a local engineer.

:)

Go for your life with any of my old threads, I'm here for the love of cars!
For this forum, it is obviously about Alfa Romeo's.
The reason why a lot of my threads and posts tend to be rather 'left wing', is rather than regurgitate what has been written or asked (regardless of brand or breed) 1000 times or more before, I'd rather ask or post comments that promote extra thinking.
Seriously(SERIOSLY!!!), I get pissed off with reading regurgitated ignorant crap that was nothing more than a misinterpretation of a misinterpretation ('Alfa transaxle cars have a crap gear change because the gearbox is a long way from the gear lever' kind of crap!).
If 1 of my threads gets dug up 1 or 10 years later, I'm all for it, if it helps with other people's love of cars.

Sheldon McIntosh

Quote from: Duk on June 08, 2012, 04:04:17 PM
The reason why a lot of my threads and posts tend to be rather 'left wing',

What do you mean by that?  (Honestly just curious what you mean, not trying to start an internet war)

Duk

#20
Quote from: Sheldon McIntosh on June 08, 2012, 04:14:28 PM
Quote from: Duk on June 08, 2012, 04:04:17 PM
The reason why a lot of my threads and posts tend to be rather 'left wing',

What do you mean by that?  (Honestly just curious what you mean, not trying to start an internet war)

Firstly, LOL (at myself)!
I've posted that, a little out of context, on here.
I'm a member of a 5 car forums. 3 are for Alfa's, 1 Toyota and 1 for Adaptronic (programmable computers) and it's easy to misplace what I've posted, where.

Also, over the years I've read as much as I can get my hands on, about cars.
More specifically, in the last few years, about what I believe makes a really good road car.

For me, that is  car that deliver a really broad torque curve (not that a centrifugally supercharged Alfa would do that particularly well (for its capacity), but a twin-charged, 1.6 litre MR2 did(the supercharger is dead  :()  8)), rather than just chasing some 'amazing' peak power number.
As an example, my now sold, 'slightly modified' RB20 turbo 6 powered S13 Silvia pulled 7500rpm in 5th gear (IE: VERY FAST!) and was still accelerating, but sucked when driving around town. This was with only a modestly bigger turbo (320hp Garret roller bearing turbo with a .64 A/R turbine housing. A turbo that was aimed at being a good 2 litre 'road car' turbo)......

It's about cars that handle REALLY well in all conditions, but especially on bumpy roads (get a standard, 'floppy chassis' but over sprung and/or over bump damped car, with overly fat anti-roll bars, on a bumpy road and see what I mean) as well as ride well.

It's about shrinking the ports of an engine to get better average flow than to chase the highest peak flow (For my MR2's engine, where I shrunk the 'big port' head's inlet ports, as well as made a new inlet manifold and gained a VERY noticeable improvement in low RPM torque at the same time as adding much more top end power. Read: 4th gear @ 40km/hr and it still accelerated very well).

It's about changing geometry of a suspension system and steering alignment (well, caster angle), so keeping a tyre's tread flat on the road surface to get the maximum average grip from a tyre, rather than rely on stupid amounts of negative camber and fat antiroll bars.

It's about adding torsional strength to the chassis.

It's about moving the reasonably movable masses (like a battery) towards the centre of the car. Or more specifically, moving or reducing weight forward of the worse performing end. For the understeering Alfa transaxle chassis, reducing weight forward of the front axle line. Unfortunately I'm going to contradict myself with bigger radiators and added heat exchangers..............  :-[

The reason why I call this sort of thing 'left wing', is because it goes against the norm.

It's funny how many people think you need a huge cam/turbo/supercharger to make a decently quick road car. When in actual fact, using 'smaller' cams/turbo/supercharger gives a much better average performance.

It's funny how many people think that the first thing that should be done to a cylinder head port, to make it flow better, is to increase the port's size. Some cylinder head ports are over sized for their valves. Shrinking the ports can give a real world (road car) advantage. Plus 'big ports' can  give an overly low air speed and that results in poor acoustic tuning characteristics, especially at road car type engine speeds. While I haven't looked at the 24 valve V6's ports, my guess is that they are too big, just based on the torque numbers and the peak speed that is was produced at, not to mention the lack luster over all performance that people struggle to get from the engine (How many road going, modified 100hp/litre 24 valve have you genuinely read about? Very few!).

It's funny how many people think that you need to resist the movement of the suspension when it goes over bumps or leans with lateral weight transfer, to go around corners faster. But systematically ignore the purpose of suspension, to help the tyres and the car's occupants to deal with bumps in the road. Lateral weight transfer happens regardless.

It's funny how many people think that improving the performance of a car instantly means it has worse fuel economy. If higher average torque is achieved, then higher overall gearing can be used. Frictional loss doesn't go up proportionately with engine speed, it goes up at a much faster rate. By having an engine with a lot of low RPM torque, it can then turn a taller overall gearing and gain a cruising and acceleration fuel economy gain.

It's funny how many people suggest using a lower diff ratio for better performance. Performance that might be used less than 10% of the driving time, rather than aspire to get the engine to be more torquey

It's funny how many people dismiss the importance of aerodynamics in a road car. At road car speeds in a road going car, there is very little chance of developing actual down force. But the real world reduction of aerodynamic drag of a road car, can certainly be achieved. Even by a back yarder, so long as you arm yourself with real world knowledge.

It's funny how many people dismiss the achievements of other, seemingly lesser brands of car, because they have this belief that their own supported brand is somehow 'so much better'..............

I could go on and on and on............