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Old 03-03-2012, 11:33 AM   #1
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Default Easy changes to static corner weight?

What are the easiest components to move around in a miata to adjust static corner weight? Are there many? Or better yet; are there any that are specific to a miata?

- Ballast
- Battery
- Fuel cell if applicable
- Catch cans/overflow tanks
- ??


Ive heard the tall tales of SM drivers using large batteries and 10lb shock mounts on the rr.

What are y'all doing to improve right rear %?
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Old 03-03-2012, 02:16 PM   #2
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Nothing. My RR is crazy light, something in the 450lb range. I'd always rather have less overall weight than trying to load up the RR with junk. I still have 50/50 crossweights, though. Anything else on that corner (battery, overflow, etc) requires that you run a bunch of line or cable back to it, which adds weight. My battery is in the passenger footwell (as God intended it), and it vastly reduced the amount of cable required to hook it up to everything.
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Old 03-04-2012, 09:34 PM   #3
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remove weight from one side, add ballast weight there based on your classing. Otherwise, there is not much to move around without adding weight to another area (ie wires, or cabling, or tubing, etc.). Its probably better to be lighter and do the rest through corner balancing with the ride height than to add extra weight just to improve the unsprung weight distribution.
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Old 03-04-2012, 09:46 PM   #4
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Spare tire? Remove the actual tire if it's too much.
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Old 03-05-2012, 08:08 AM   #5
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Choose a RHD one to begin with
No exhaust near you feet, near your brake MS, etc etc.
I have a spare one, just in case I crash the tub I'm running now (fooling Murphy ).

If caged a plastic drivers door (GF or CF doesn't matter) would help a lot. But as mentioned, overall weight seems to be more important than balance as long as yu can reach the desired CW.

Lighter driver...
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Old 03-05-2012, 10:49 AM   #6
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Ton (the 8min BTG guy) told me about some experiments he did on an old Volvo rally car. Basically running stages with and without ballast weight in the trunk to get F/R distribution back to spec. I remember the results as the car being equally quick because the car was easier to extract speed from with improved weight balance. After seeing his datalogs for the Nordschleiffe (0.83% max variation between hot laps over 20km) I tend to trust the repeatability of his experiments.

Anyone else out there that did comparisons? I'm sure both configs are driveable, but could image L/R distribution having a different influence then F/R distribution.
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Old 03-05-2012, 12:03 PM   #7
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Quote:
Originally Posted by damir130 View Post
Ton (the 8min BTG guy) told me about some experiments he did on an old Volvo rally car. Basically running stages with and without ballast weight in the trunk to get F/R distribution back to spec. I remember the results as the car being equally quick because the car was easier to extract speed from with improved weight balance. After seeing his datalogs for the Nordschleiffe (0.83% max variation between hot laps over 20km) I tend to trust the repeatability of his experiments.

Anyone else out there that did comparisons? I'm sure both configs are driveable, but could image L/R distribution having a different influence then F/R distribution.
With the same shocks and springs I would agree. But to say a lighter car cannot have its suspension adjusted to work with the lighter rear and actually produce faster times is wrong.

If that were the case every Porsche would have an anvil in its front luggage compartment, and last time I checked thats not even a dealer option. If you know a bit about porsche you'd know if they can make it a option and charge you money they most certainly will.
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Old 03-05-2012, 12:56 PM   #8
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Quote:
Originally Posted by AnnorexicRoadster View Post
If that were the case every Porsche would have an anvil in its front luggage compartment, and last time I checked thats not even a dealer option. If you know a bit about porsche you'd know if they can make it a option and charge you money they most certainly will.
Some models in the 70s had a "lead" front bumper ...
And 911s are a special case, balanced by tire width, trailing arms and whatnot

The Miata is not as unbalanced as other track victims are when they get lightened. Some local E30's have been faster in a competitive series by going 20lbs over min weight just to get balanced, but then they were prohibited from moving things around too much.
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Old 03-05-2012, 02:48 PM   #9
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Not interested in theoretical CR debates. Interested more in hearing experiences from people that have tried different things (which seemingly happens a lot in spec miata).

Porsches are pretty much near an ideal @ 40-60, totally different from anything you'll encounter in a miata. Not sure what point you are arguing?
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Old 03-05-2012, 04:23 PM   #10
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Quote:
Originally Posted by damir130 View Post
Not interested in theoretical CR debates. Interested more in hearing experiences from people that have tried different things (which seemingly happens a lot in spec miata).

Porsches are pretty much near an ideal @ 40-60, totally different from anything you'll encounter in a miata. Not sure what point you are arguing?
Point I'm arguing is that is it better to be lighter then perfectly balanced. Unless you have a minimum weight that you have to make and are currently too light for your class there is no point in throwing weight back into your car.

Spec miata guys do it because they have a minimum weight to stay legal. In this case, and especially since they cannot change spring rates/damper rates corner ballasting is effective.

Savington's black car is very light in the rear and especially on the rear right corner but that doesn't mean he is going to throw weight back into the car.

Every FWD race car is gutted in the rear and no one leaves any weight in the back because light is faster.

Make your suspension work for your front rear weights and when you get a alignment invest the extra cash and get it corner balanced with you in the car.
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Old 03-05-2012, 04:26 PM   #11
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Quote:
Originally Posted by NiklasFalk View Post
Some models in the 70s had a "lead" front bumper ...
And 911s are a special case, balanced by tire width, trailing arms and whatnot

The Miata is not as unbalanced as other track victims are when they get lightened. Some local E30's have been faster in a competitive series by going 20lbs over min weight just to get balanced, but then they were prohibited from moving things around too much.
To add to your point, the "lead bumper" was a compromise. Then Porsche engineers focused on modifying the suspension as you mentioned to get the car to work with the rear heavy setup.
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