With my LFX swapped miata, my weight distribution is 56% front and 44% rear ( 2338 total with me in the car and 8 gallons of fuel, so roughly 2,110 lbs total dry)

I have done some calcs and moving the radiator, oil cooler, and fire bottle to the trunk would result in roughly a 52/48 distribution afterwards. That's taking raw weight and not taking into account how far off the nose the radiator is actually hanging, so it may get a little better than that. And also the ability to remove a bunch of unnecessary metal/brackets from the front of the car.

Obviously there would be a ton of work involved including working out efficient ducting that doesn't mess with rear wing's efficiency.

Would that much change in weight distribution have a noticeably beneficial effect on handling? Aero benefits not having a large opening in the front of the car? It would also open up a world of splitter diffuser options not having anything in the way.

Thanks,
Ryan

 

I’d be concerned that in a situation where weight is a concern that a fire would be a genuine concern and having your extinguisher in the trunk makes it useless.

Are there any any other mods you can do to remove front weight? Maybe lighter weight brakes? Lighter control arms?

 

The fire bottle is for the fire suppression system in the car. The bottle can be anywhere and is activated by either of 2 pull handles. I also have a hand held mounted in the car and that will remain within my reach.

Brakes are already as light as can be (Stoptech STR42 kti) and are un-sprung weight, so no big impact there...

Control arms are V8Roadsters Pro arms. Could go back to the aluminum option that I originally had on there, but they are too fragile in case of off-road excursions/impacts and wouldn't be repairable like the steel are. The V8R pro steel arms are still lighter than stock.

The car is already hacked to pieces on the front with only the bare minimum remaining. As far as additional weight loss by removing pieces of car from the front, the only way would be to tube frame the front or go to a lexan windshield.

I'm not looking for advice on weight removal as I have a very good grasp on that, but information related to what kind, if any, of noticeable improvement in handling characteristics could be expected from a shift in weight distribution closer to 50/50. To move the radiator, and oil cooler to the rear would require a pretty substantial amount of work and I want to see if the community consensus is that the improvement would be noticeable.

 

My experience has been that MOI (polar moment of inertia) has a greater effect on handling and lap time than raw weight distribution. Negative effects of poor weight distribution can be partially mitigated by driving style and car set-up. No amount of set up magic or creative driving offsets a car that is basically a barbell. So I always work to move as much mass to the center of the car within the limit of the rules, and whatever packaging constraints I am presented with.

FR (front-engine rear-drive) platforms want about 55% on the back tires. Really tough to do on an NA/NB Miata because most of the weight reduction from race prep usually comes off the back of the car. Most of the stuff you add on for race prep goes on the front, oil coolers etc.

 

Thank you. The radiator and oil cooler are hanging pretty substantially off the front axle, and would be relocated just behind the rear axle, so it should help both distribution and MOI, i would think....

 

How tall are you?
Also, do you run any aero?
FWIW I'd leave the coolers alone.

 

5'-10"
Swapping the gt-250 rear wing to a gt-1000 tomorrow...
Front 5" splitter w/ 3 diffusers and air dam. Front fender vents above and behind the wheels. Barge boards.

Likely going to try a front mounted wing in the next month or so....

 

At 5'10" you're probably sitting a few inches ahead of the rear bulkhead, which makes you the easiest chunk of weight to move in the car.
Take your seat and move it all the way back, extend pedals backwards, space the steering wheel, bend the shifter backwards, profit.
If you need help, I know a fabricator that has done it already

What's the splitter made out of?

 

Just to vouch for you, I've seen this done as well. It is a little time consuming to do, but can be pretty effective. In another front engined RWD car, I've seen them put the driver nearly two feet further back. I'm blanking on the model but it was a two door coupe.

 

This is absolutely true. There's a point though where you have to compromise between MoI and CoG height, which is very case dependent, tires included.

 

A good weekend or day spent looking over the front of the car. and picking apart weight you dont need to can change would help.
sure put the fire bottle in the rear middle. low as you can.

I like to put my weight in the center of the vehicle as best i can. and as low as i can.
fiber glass hood and fenders?
gutted and redone headlights.
look at the front drive on the engine and wiring and spare sensors. can you move any of them back. or down?

 

I'm really surprised it's that nose heavy. My LS3 is only 53% front. Do you still have A/C and P/S? I removed those on mine.

 

No ac, no p/s. It's likely more a result of easy massive weight removal from the rear as opposed to excess weight on the front.

 

Precisely. All light Miatas are nose heavy.

 

My guess, you move all that to the rear, you car will forever overheat. If you insist, I'd do the lightest setup possible with keeping a radiator for the engine coolant in the front, move the rest to the rear. I think you will compromise cooling too much with a rear mounted radiator.

 

I would imagine you could get the car balanced at speed by moving your center of aerodynamic pressure aft of your center of gravity. I think that wouldn't be an issue with your large rear wing and diffuser, or else you are planning on some pretty exotic front diffuser elements. Unless you are trying to fix handling issues at speeds below where you are generating significant rear downforce, you should be able to balance the car with the aero more easily than with moving physical weight to the rear. Of course this will do nothing to improve your MOI, but if you are having problems with steady state balance rather than transitional handling, it should help. Are you trying to fix a specific handling issue, or just trying to get the front/rear weights closer before you go further with aero development?