Weight distribution question

[MrMazda92]

Has anybody attempted to get close to 50/50, or even the mystical 4 corner balance?(25/25/25/25) in an MX-3?

I'm shooting for as close to 50/50 as I can manage... Basically I'm looking for suggestions, possibly big ones that I've missed.

1. A/C will likely be removed - Lots of weight here, but I am still debating it.

2. I will do what I can to shift weight in the engine bay back towards the center of the car. Everything that can be moved reasonably will be, since I'm planning to wiretuck it during the engine swap.

3. Full size spare tire in stock location.

4. Battery relocated to trunk - I think it's ugly, but the distribution is more important to me. - Even considering a larger battery for multiple benefits, the least of which being added weight. Maybe multiple, narrower batteries tucked cleanly, if my OCD beats out my financial sensibilities.

5. I'm thinking I will leave my sub in at all times, or nearly all. It's ratchet strapped down, with only enough give to accommodate chassis flex.

6. Considering running lighter wheels on the front tires for race days. Maybe RPF1s for the front, OEM 5 spokes for the rears.

7. I WILL be running gutted stock headlights, removing windshield wipers(arm and all), as well as the passenger seat for race days. I have already swapped from auto to manual belts.

If you have any suggestions, or constructive criticism to add, please feel free to! That is the purpose of this post!

Please try to avoid flaming, I'm asking you for help afterall.

[fowljesse]

I have corner balanced mine as much as possible, but you'd have to add so much weight to perfectly balance it, that it would kill your performance. However, I have achieved neutral handling (it doesn't understeer, or oversteer), and I think that's what you're going for, anyway, isn't it?

[MrMazda92]

I'm definitely going for neutral handling. I can't help but feel that the rear just lifts up on corners; despite the car being FWD it's disconcerting, and I want to be in complete control at all times. I need to go through your worklog again...

[fowljesse]

The Whiteline swaybar, and bushings make a huge difference, and everything works together. Next time you're in town, I can finally give you a ride.

[Nd4SpdSe]

Why not put in an SOHC B6, or even better, pop in a B3

Remove the front rebar, replace the front bumper with fiberglass ones
Fiberglass fenders
Custom aluminum intake manifold (a la CZT)

[MrMazda92]

I am currently scraping together enough for an SRD tie bar and Crossmember, after which I am thinking front and rear swaybars. Wytbushings are on the list too, but I'm thinking the SRD stuff is more pressing, as it won't be around for much longer, at this rate.

Nd4Spd, removing safety equipment is NOT on the to-do list! I forgot to mention that...

[SuperK]

Remove the engine, cut out a hole on the floorboards right in front of the driver's seat and passenger's seat. Get buddy to join you. Start RUNNING.

YABBA DABBA DOOO!

[MrMazda92]

Remove the engine, cut out a hole on the floorboards right in front of the driver's seat and passenger's seat. Get buddy to join you. Start RUNNING.

YABBA DABBA DOOO!

I almost put this in my sig... but then I thought, I'll just keep bumping the thread!

[Josh]

nice, ^^^

I am going to get my car W&B done again this summer. It was done before I got it but the rear end was way high and that doesn't seem right to me. when they do it, they do it from corner to corner not front to rear or left to right. The paper I have says that the car was at like 47% in the center. for a FWD car that is pretty dead on.

But I lowered the entire car 1/4" all the way around just a couple weeks ago. and added 2 infinity 12's with a 1 fared cap and 3K watt amp. so it made the rear end sit right where I wanted it to

it is removable for track days

[MrMazda92]

I'm still debating racing with the sub in... I'm shooting for 250 BHP, and if all goes to plan I won't mind having the weight back there. Still, Jesse is right with what he said. Weight will help though, when it comes to slinging the car around corners.

[Inodoro Pereyra]

Ok, here's some info. I will go by the numbers, so I don't complicate the thing.

First, a perfect corner balance, or even a perfect F/R balance would be very difficult to achieve on a street car, unless it's directly derived from a race car (think Ferrari-McLaren). The reason for that is because, to achieve a perfecct, stable balance, you'd need the gas tank to be perfectly centered around the geometric center of the wheels, so the CG won't shift as the fuel level changes.
Besides that, EVERY weight on the car should be considered, including yours and everybody else's riding it.

Now, to the questions.

1. If you're going for a track only car, you SHOULD remove the A/C, not only because of the weight, but because it robs power from the engine. If you want to use it on the street, I'd keep the A/C. But then again, I live in Florida...

2. Sounds good.

3. You should get the car balanced without the spare tire. On the track, weight is the enemy, so everything that's not necessary for the race (including the spare) should stay behind.

4. Relocating the battery is a good thing. Getting a bigger, heavier one is not. If you're serious about racing, you should do everything in your power to reduce weight, not to increase it. Also, make sure you put the batery in front, or directly over the rear axle, NEVER BEHIND IT. Otherwise, if you get rear ended, you're bound to receive a sulfuric acid shower. Not fun at all.

5. Answer #3 should apply to the sub as well.

6. On the track, at least, you should use lighter wheels all around. Not to help with the balance of the car, but to reduce, as much as possible, the car's unsprung weight, therefore improving the car's handling, and its capacity to transfer the engine's power to the pavement.

7. Gutting the headlights will make a negligible difference, and it'd be a PITA on a dual purpose car. Removing the wipers would make no difference at all, and would make for a very short race day, if it starts raining...

The proper way to balance a car for racing is to lighten the heavy end, not to add weight to the light end. Get rid of the PS. Swap the front fenders and hood for composite units. If you're using the car only for the track, swap the front windshield for a lexan one. Also, think of the items you can live without on the track: the coolant reservoir, for example, probably weighs 6 Lbs or more when full. Get rid of it.

As usual, you have to define what you want first, and then decide what to do. An all out race car would be a nightmare to drive on the street. A comfortable street car would not get far on the track. A dual purpose car will mean a compromise between things that are, most of the times, opposite to each other. You have to decide how far you want to go either way.

[fowljesse]

Yoda wrote a great bit about all of this. I don't feel like looking it up atm, but it's very interesting. I followed his advice, and some new knowledge, and have pretty neutral handling. You can just copy my setup. The weight difference is made up for with suspension components. My car is so off balance front to rear, that when I jack at the front jack point, the back wheel comes up too!

[Mooneggs]

My car is so off balance front to rear, that when I jack at the front jack point, the back wheel comes up too!

This is pretty normal for all mx-3s.

And I agree with everything Inodoro said... They won't even allow you to race with a spare, sub, or anything else that could fly around. Get rid of your A/C! It will save you +/- 40 pounds off the front end!

[SuperK]

I think relocating the battery to the back would be best, and some people can hide their batteries in the space behind the trunk panels too. Or you could make an enclosure and carpet that enclosure too. It sure does make the engine bay look nice though!

[MrMazda92]

Now THIS is what I had in mind when I posted this, guys! Thank you!

Good point on keeping the battery out of harms way Inodoro, this is why I had to post this. Forums are great!

I won't be living in Oregon for too much longer, so the A/C is still a debate for me. If I knew I was staying here, it would be long gone already! Hot weather kills me, I like nothing above 90 ish degrees.

I'm happy to reduce unsprung weight wherever possible, I was under the assumption that(because unsprung weight counts more than sprung weight) that staggering the sprung weight would have a greater effect on the "balance" of the car than altering the sprung weight. There are probably a dozen reasons why this is wrong, though.

The headlights are shockingly heavy, and they're at the VERY front of the car! I have an extra sat already, so why not? Basically it'd be a plastic lens and 1/3 of a housing(enough to hold it's shape and still be attached via 1-2 bolts)

I rather liked that idea

The wiper blades are both for the reduced weight, as well as a slight drag reduction(every little bit counts, right?)

I'm torn on the powersteering, as I am on the A/C. I've driven several cars without it, and some were much less of a PITA than others.

My coolant reservoir is gone already, as is the plumbing that directs it to the hood. The nozzles will be gone come painting time.

I want to move my cruise control farther back in the bay, somewhere neater, if at all possible. I forgot to add that to the list before.

The car will be dual purposed, not track only. If it were, things would be so much easier...

Jesse, I'm digging through some of Yoda's posts as I browse right now. In particular his thoughts on the G series trans are making my brain itch, was there really a diesel engine mated with a beefier G series?

Mark, I was unaware of that information. Thanks for the heads up!