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Discussion Starter #1
Hi:
As I mentioned in a few other threads, I'm prepping a 95 Ford Thunderbird LX for a 24 Hours of Lemons track race.

Now that the interior is gutted, I'm slightly concerned that the car might be riding a little high. One thought is to cut the coils or find appropriately sized ones for a heavier vehicle (like a truck) and cut those down.

Yes, this is probably a bad idea for a street driven car. This car isn't going to be driven on the street.

Yes, there are better ways to do lower your car. In LeMons, we have to work within a $500 car+upgrades+fixes budget so we can't "afford" a nice aftermarket suspension.


Q: Can you guys give me the stock spring specs for a 95 Thunderbird?
I.e.: Coil wire dia, overall spring coil diameter, Installed length, free length, load, and rate?

I'm not sure if it's the same across the MN12 line but I have done some searching and this is what I've found. I'd appreciate it if you guys could confirm things here.

- They are progressive springs
- Rate: 330Lbs to 550Lbs (not sure if this was for all cars or just this guys LX. Aren't the fronts different from the rears?)
- Wire diameter: .7"

In the manual, all I could find was a single part #s:
Front = 5310
Rear = 5560

Google didn't return anything useful for me here.

http://forums.tccoa.com/showthread.php?t=52902

Thanks in advance for your replies.

Regards,
-g
 

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Have you looked in the tech Articles? There is a lot of information in them.
 

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Discussion Starter #6
Ahh, my problem is that I simply looked under suspension. I never noticed the MN12performance HOWTOs and Tech articles subsection. You guys should combine them.
-g
 

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cutting springs

Hi

Remember when you cut a spring it gets stiffer.

also the front springs are about 18" long, then compressed.

I have about 500-600 front springs & 300's in the rear.

Get a early SC front sway bar. (1.10-1.20)

:cool:
 

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Discussion Starter #8
Hi

Remember when you cut a spring it gets stiffer.

also the front springs are about 18" long, then compressed.

I have about 500-600 front springs & 300's in the rear.

Get a early SC front sway bar. (1.10-1.20)

:cool:
Front: 223-282 lb./in.
Rear: 361-501 lb./in.

According to the previously given link, these are my default spring specs.
Since my car is on its way to being lightened, I figure my weight distribution is probably quite heavily front biased. I also notice that when I brake hard, the nose dives a bit.

A few days ago, I measured the ride height just behind the front and rear tires.
Front: 7.5" tall
Rear: 8.5" tall.

I'm trying to understand your recommendations for a heavier front spring.
Q: A heavier front spring will help offset the front/rear weight distribution, right?
If so, wouldn't it also increase understeer as well?

Q: Also, your recommendation for a stiffer FRONT anti-sway bar will just further increase understeer?

I thought neutral/slight oversteer is what I would want for a road track or even circle track racer? I can't imagine your front wheels resisting a turn would help you get around the the corner faster.


Thanks in advance,
-g
 

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dive

Hi

That dive you mention changes your caster/camber numbers.
your ackermann steering also comes in.

All good when going straight, But as soon as you turn weird things start to happen.

I do get a push. will be lighting the front springs, But not as light as stock

I also run a small rear bar.

:zbench:
 

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There is nothing about that in the tech articles.
That's what I get for not clicking on it. With the title "Lowering Springs" it made sense to me that it would have only mentioned the aftermarket springs.
You can't say theres nothing when you haven't looked at everything in the tech articles.

Ahh, my problem is that I simply looked under suspension. I never noticed the MN12performance HOW-TOs and Tech articles subsection. You guys should combine them.
-g

They are combined in the same place and that would be the Technical Articles hompage. :rolleyes:

There is more to this website than just the forum...

I even rewrote how to find them in the Newbie forum.

AND

Gordo linked them in the "Very helpful Tech Article Links" thread.
 

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Apology accepted.

No, that's not intended to be a further berating of you, that's just a general observation that applies to you and a lot of people besides yourself.
 

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I suspect your weight distribution is not as bad as you think. Especially with a 3.8V6, you're probably in pretty good shape as far as that goes. The problem is the V6 springs are weak as hell. Try to get yourself some SC or tbird sport springs, then start cutting coils off. On our lemons car we have 1.5 coils off all 4 SC springs, and it handles quite well. Plus you can probably pick up a set of SC springs for under $100, and once they are on the car, it will be just another factory part so nobody will notice it at the BS inspection.
 

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You can't say theres nothing when you haven't looked at everything in the tech articles.




They are combined in the same place and that would be the Technical Articles hompage. :rolleyes:

There is more to this website than just the forum...
I'm a big fan of your tech articles; I apologize as well for missing a seperate category for MN12performance.

Maybe this is a stupid question, but why are the MN12Performance articles listed under under a separate subheading? In other words, why not just file THAT specific article (the one about springs) under the suspension category?

-g

I suspect your weight distribution is not as bad as you think. Especially with a 3.8V6, you're probably in pretty good shape as far as that goes. The problem is the V6 springs are weak as hell. Try to get yourself some SC or tbird sport springs, then start cutting coils off. On our lemons car we have 1.5 coils off all 4 SC springs, and it handles quite well. Plus you can probably pick up a set of SC springs for under $100, and once they are on the car, it will be just another factory part so nobody will notice it at the BS inspection.
thanks for the specific tips on the parts! I'll share this with the team.
-g
 

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I'm a big fan of your tech articles; I apologize as well for missing a seperate category for MN12performance.

Maybe this is a stupid question, but why are the MN12Performance articles listed under under a separate subheading? In other words, why not just file THAT specific article (the one about springs) under the suspension category?

-g
Not a stupid question.

The reason those articles are filed separately is that they came from a different website. MN12Performance use to be MN12Performance.com but they went out of business a few years ago. We saved those articles from being lost to the abyss where websites go when they die.

When they were copied over they were just kept in their original format and not integrated into the technical articles of this site.

Ron
 

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I'm trying to understand your recommendations for a heavier front spring.
Q: A heavier front spring will help offset the front/rear weight distribution, right?
If so, wouldn't it also increase understeer as well?

Q: Also, your recommendation for a stiffer FRONT anti-sway bar will just further increase understeer?

I thought neutral/slight oversteer is what I would want for a road track or even circle track racer? I can't imagine your front wheels resisting a turn would help you get around the the corner faster.


Thanks in advance,
-g
Hi

Remember I have an Iron 351W engine. Way heavier than a 3.8 V-6

:)
 

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Discussion Starter #18 (Edited)
Hi

Remember I have an Iron 351W engine. Way heavier than a 3.8 V-6

:)
Ahhh. I'm still learning about domestic engines.
351W aka 351 Windsor long block = 510Lbs
3.8L NA from a tbird aka Ford Essex V6 3.8L = 238Lbs

Yeah, I'd say that's a bit of a delta.

I have about 500-600 front springs & 300's in the rear.

With that big an engine and 500-600LB/in front springs, you front springs are compressiong at least 1 inch (additional weight offsetting the springs).

Right now, with my weenie engine weight and 223-282 lb./in front springs, it sounds like they are being compressed the same.

If I upgrade to SC springs (Front: 223-282 lb./in) as I've been recommended, it looks like I won't be compressing (pre-loading, right) the springs nearly as much. I see now why I would need to cut them for my application.

-g
 
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