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67TXStang
01-02-2012, 08:55 PM
I'm curious and hope someone can point me in the direction to learn more on managing vehicle weight.

I've often heard reducing the weight of a vehicle is one of the easiest and cheapest ways to increase vehicle performance. When I hear this, I start to think about items which could be easily removed from my '67 Mustang.

There are things which come to mind which are at the rear of the vehicle... spare tire, full fuel tank, etc. As often as I hear about reducing vehicle weight, I hear about weight over the rear wheels of a rear wheel vehicle allowing for greater traction. My car is currently front heavy which makes it seem like removing items from the rear of the car would make things worse.

Is it more important to just work on reaching a 50/50 weight distribution rather than just overall vehicle weight?

novaderrik
01-02-2012, 10:57 PM
take off everything you can live without, and mount most of what's left over farther back.. moving a 50lb battery from the front of the engine bay to the trunk is a 100 pound front to rear weight swing, and moving it from the driver's side of the car to the passenger side helps offset the weight of the driver.
does the hood really need all that bracing underneath it, or could you afford to just get a lighter fiberglass hood in place of the steel one? and aluminum radiator is lighter than a stock copper/brass unit, but some of that weight loss may be negated by extra coolant if it has more capacity. do you have AC- and if so, could you live without it? this is all weight taken from the front of the car without taking anything away from the rear..

Bryce
01-03-2012, 08:51 AM
I have my falcon weighing in at 2650 now.

Complete fiberglass front end, valance, fenders, hood.
Aluminum heads and manifold
Aluminum radiator core support
Aluminum steering column
Fiberglass trunk lid
Lighter front and rear suspension
Lighter front seats
no rear seat
no heater or AC

probably more that I cannot think of right now.

carguykeith
01-03-2012, 10:33 AM
I am curious to hear the answer on this one too, I went ahead and just took as much weight off of everywhere I could. I did worry about the bias when I took of the heavy as* rear bumber and stock fuel tank to replace them with much lighter pieces. Would love to 4-corner weigh my car but there is literally nowhere in the state that does it!

Sure I put the battery in the trunk but the damn think only weighs like 7lbs...

John Wright
01-03-2012, 12:02 PM
May depend on whether you want to handle well in the turns or simply get traction from a stand still.

Norm Peterson
01-04-2012, 09:16 AM
Most experienced autocrossers remove the spare even though it's permissible to leave it in place if it's securely held down. Many will run with only enough fuel to prevent fuel starvation issues. Obviously, these are temporary measures not particularly applicable to street driving.

There is a third variable here, polar moment of inertia about the Z-axis (vertical), which affects how easily (or not) a car can be made to rotate. It's possible to reduce this at the same time that the front weight% increases if you remove heavy things from out toward the back end of the car. Which prompts the thought - if you're going to pull the rear bumper or replace it with a lightweight replica, you might as well do the same for the front.


Norm

exwestracer
01-04-2012, 04:58 PM
Not sure about the 67 Mustang specifically, but Fords in general placed the engine further forward than necessary. A lot of people seem to think moving the engine doesn't make much of a difference, but it does; especially as you begin to get the total weight down as well. I'd move the engine as FAR back as possible, and keep as many components as possible between the axles.

shortrack
01-04-2012, 09:09 PM
Would love to 4-corner weigh my car but there is literally nowhere in the state that does it!

Find a stock car racer.....offer to pay

what state would that be?

NJSPEEDER
01-04-2012, 11:32 PM
I think the biggest thing that you can read into all this discussion is that you are right, it is just as much about weight management as it is weight reduction. Ultimately the lowest weight possible is the right answer but that is tempered by the fact that you need the suspension to support it if you can't distribute it as desired.

start with simple stuff, moving the battery to the back makes a massive difference.
if you have access to a hole saw set go to town on the bracing for the hood. it doesn't seem like a handful of holes would make much of a difference but it is up front and up high, that's as bad as sprung weight gets!!!
look at stupid stuff like your fenders, how many bolts does it really take to keep a fender from running off to start a life of it's own at the hippy commune?
You can also usually find a variety of brackets and such made of steel that could easily be replicated out of aluminum from the local big box hardware store
There is also the possibility of learning to make your own molds for fiberglass(there are seriously a million online how-to's) to replace non critical parts made of heavy plastic or steel.
There are also a lot of lifestyle decisions, living without A/C was already mentioned but also consider pulling up the carpet and removing all the padding/sound deadeners/seam goop the factory dumped in the car.

exwestrace makes a great point about fords engine placement, especially on older vehicles. In the 50's and 60's ford belived that making a car that could be serviced easily was valuable to their dealerships who were expected to perform the service so their design requirements included some degree of putting the engine out where 5 guys could climb in and work on it together. See if anyone makes or if anyone local can help you fab mounts to pull it back and drop it so that the pan is closer to the height of the bottom of the cross member.

-Tim

67TXStang
01-05-2012, 07:29 AM
Thank you for all the responses. I've quite a bit to learn.

I've room to move the engine back. There is room around the firewall to move the engine back an inch or two. I would need to modify the transmission mount if I moved it back more than an inch. Additionally, I'd start to have trouble with the shifter openning after moving it back and inch. I might be able to move the engine down and inch as well as there is at least that much clearance between the oil pan and crossmember.

I've not moved my battery but it is on the list of things to do (it weights 45 lbs!). I understand how it better balances the weight between the front and back but I'll likely add 10 lbs of wire to connected back to the front location which seems strange when you are trying to save weight. I guess it is not a perfect world and you make compromises to get things at least a little better.

I've switched to aluminum heads and intake. These cut down the weight on the front end by at least 50 lbs. I'll need to swap out my starter with a mini version. Suprisingly, the stock starter weights in at about 17 lbs.

I'm thinking of switching out my radiator to an aluminum version. I've also considered doing something with the seats as my bench seat (yeah, its a bench in a Mustang), it a little heavy.

I'm most interested in street performance (acceleration and cornering). I'll start with reducing the front weight as much as reasonable and then turn my attention to overall vehicle weight.

Any other ideas are certainly still welcom.

John Wright
01-05-2012, 07:46 AM
My questions were leading up to this:


There is a third variable here, polar moment of inertia about the Z-axis (vertical), which affects how easily (or not) a car can be made to rotate.

Think Porsche 911 or VW for a moment(opposite of your situation).....motor hanging way over the tail end, out behind the rear axle. Your car has the motor way forward, so moving it towards the CG helps the F to R ratios. The farther these heavy items(engines, batteries, large bumpers) are from the front to back Center of Gravity, the more effect they have...ie. longer pendulum effect. Keeping them as close to the front to back CG helps you be able to get the car to turn/rotate.

Norm Peterson
01-05-2012, 09:06 AM
I've room to move the engine back. There is room around the firewall to move the engine back an inch or two. I would need to modify the transmission mount if I moved it back more than an inch. Additionally, I'd start to have trouble with the shifter openning after moving it back and inch.
I wouldn't consider having to modify or even completely redesign the tranny crossmember to be a deal-breaker given that I really was serious about managing weight and its placement.

Some transmissions - I think at least the Tremec 3550's/TKO's - offer multiple shifter locations, assuming that you'd rather not bend the lever sharply forward putting the pattern in a skew plane rather than horizontal-ish as Carroll Shelby did with the Cobra shifter.


Most of the extra battery cable will be positioned within the wheelbase, so at least the wt% and PMOI effects are minimized. For PMOI reasons, you'd like to get the battery inside the wheelbase as well, but that may not be practical or even possible given sanctioning body rules concerning battery isolation from the passenger compartment.

Consider an aluminum water pump. An aluminum block would really be nice, but likely a lot harder to justify.



Suppose you moved the engine back far enough that you needed to massage the firewall a bit. And then had to move the pedals back a bit so that you could get both of your size 13's to fit in the pedal box without hitting two pedals at once, and then the seat (and your weight) had to move back by the same amount. Seems like that shifter location might become a little more flexible at the same time . . .


The altered wheelbase drag cars of the 60's moved either or both axles forward under the chassis/body specifically for weight distribution reasons. You could probably get away with an inch or so relocation without the car looking odd with a little reworking of the bodywork. In a 108" WB car, relocating each axle forward by one inch is good for shifting the weight distribution of a 3500# car starting out at 55/45 down by more than 2 percentage points if you do absolutely nothing else.

How serious are you??? And are you apt to be competing where any of the above thoughts won't pass muster or is it just going to be a matter of "running-what-you-brung"?


Norm

exwestracer
01-05-2012, 01:29 PM
IIRC, the shifter in the Mustang was plenty far forward to start with. An ex-boss had a 67 390/4sp car, and he was reaching for all he was worth to get it into 3rd...

Open the tunnel hole up, modify the mount, and move it absolutely as FAR as you can go. I think the crossmember drops out, so maybe build more "dip" into it and drop the engine until pan/ground clearance becomes an issue. You'll have more fan to rad clearance, so move the radiator back if possible.

Different pedals or spacers between the pedal bracket and firewall will move the pedals back; which isn't a big deal, but that will allow YOU and the seat to move back, which IS big.

The thing is, once you go down that road, you have to do EVERYTHING possible, or the gains aren't worth all the effort.

carguykeith
01-05-2012, 01:52 PM
Find a stock car racer.....offer to pay

what state would that be?

Yeah going to go to a couple of the races this summer and ask around, I live in Alaska and there is literally only two track in the whole state...



I've not moved my battery but it is on the list of things to do (it weights 45 lbs!). I understand how it better balances the weight between the front and back but I'll likely add 10 lbs of wire to connected back to the front location which seems strange when you are trying to save weight. I guess it is not a perfect world and you make compromises to get things at least a little better.

Damn, that's a HUGE battery! Why not go with a AGM style like a Braille or odyssy (sp?) mine is like 7lbs and has 600+ cca. Also no need for moster cables just becaue it's in the trunk, I'm running about 12ft of 2ga that weighs 2lbs and only have a couple of tenths V drop to the starter.

Norm Peterson
01-05-2012, 05:16 PM
IIRC, the shifter in the Mustang was plenty far forward to start with.
That's more or less what I recollect from when one of my friends got a '67 or '68 289/4 speed Mustang back in the day - I'm pretty sure that the OE shift lever actually had a rearward bend in it, with a two-finger lift mechanism to enable the reverse gate. Not sure how T5/3550/TKO shifter locations would compare.

I'll bet with the tricks mentioned so far that you could get one down under 50% front weight.


Norm

exwestracer
01-05-2012, 08:22 PM
[QUOTE=

I'll bet with the tricks mentioned so far that you could get one down under 50% front weight.


Norm[/QUOTE]

:cheers:

Sicarius428
07-11-2014, 12:14 PM
I have two mustangs and all are plagued with a heavy nose. My 90 5.0 is my toy and I have done weight reduction to it so I will use it as my example of things I have done or researched. Here is the list.
The obvious changes are Fiberglass hood and fenders, Aluminum heads, intake, Aluminum radiator, Electric fan, Aluminum water pump. The not so obvious ones that will also reduce unsprung weight are coilover conversion, tubular A arms and aluminum calipers. I couldn't believe how much the stock cast ones weighed... and sucked at stopping. Granted the larger disks did make up some of the difference but the stopping power of a modern caliper is also a safety improvement too. Tubular sway bar though I have never seen one for the classics but I never really looked. Wiper motor/linkage/wipers can be removed and a mini starter are options. Battery in the trunk will help. Quality aluminum wheels(within reason) will also help with unsprung weight and help suspension performance. Headers will weigh less than cast units you may have and also increase performance. Not sure what transmission you are running but a T5 weighs about 65 lbs. Depending on the sort of power you have, the T5 can be built up to be extremely stout in such a small light package and which is great for a classic. I swapped a TKO600 into my 5.0 and it is a beast. It fits the hump in the 90 but you may have to cut yours to get it in correctly. The beast also weighs 100 lbs. When I had the T5, I felt comfortable swapping out my T5 all day long by myself without a jack. That TKO is another story... In the sake of reducing weight, not cutting up the car and cost, I think a astro performance T5 would be a better option. Hope that helps.
Kevin