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What coil springs to use on a fox?


CMC#11

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I will say this from a newbie, uneducated point of view.

 

Fox body mustangs are not a 4th gen Camaro, SN95's are not a 3rd gen. etc etc etc.... but watching a CMC 3rd gen Camaro video, a 4th Gen Camaro video, and a fox body video, you can completely see the difference in stability behind the wheel. If it's track width, Components, design whatever, you cannot say that a foxbody has the stability that a camero has going through any corner.

 

Coming from a motorcycle past, and riding quite a few different types, I will say that each rider "Driver" must match his riding style to what he is on/in. And I know a few riders who prefer hanging their rear tire out... But I wouldn't dare to say that Mosty or Boudy isn't the driver that Glenn or Mitch is. I think the fox body is better on slow tight stuff, but maybe not what a Camaro is in a fast sweeper. so why argue over apple sauce and spilled orange juice...

 

You're all damn close, and you have to admit, half a second lap times for a consistent driver isn't impossible to fix with your setup... I have seen you guys pull it off in a weekend... It's always a great race to watch...

 

If I really wanted to find out about platform to driver, I would need to take out the car's variables and leave it to the driver, say 10 identical rental cars, give them new tires and brakes (same off the shelf parts), and let them all go out and duke it out (timing loop of course)... then you can eliminate quite a few different things like setup, track width, weight, knowing their car, etc. Then it's based off driver and only driver... then after those tests, you might actually be able to say weather it's setup, driver, or rules... Take out variables and get a constant, then work variables back in to come to a theory... then you can find a law...

 

but again, that's my newbie, uneducated opinion...

 

BTW, I do think a 99-04 SN95 is the best chassis, thats why I am building one... Plus, you couldn't give me enough laxative to own a smooth flowing GM...

Not that I own my mustang

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I will say this from a newbie, uneducated point of view.

 

Fox body mustangs are not a 4th gen Camaro, SN95's are not a 3rd gen. etc etc etc.... but watching a CMC 3rd gen Camaro video, a 4th Gen Camaro video, and a fox body video, you can completely see the difference in stability behind the wheel. If it's track width, Components, design whatever, you cannot say that a foxbody has the stability that a camero has going through any corner.

 

[/size]

 

I don't think a car in field at the last event was more unstable than my car on Saturday. Not often you are three wide by yourself in most every corner.

 

I still think setup has more to do with stability than platform. I know my car is no where is as stable as JeffW's or JeffB's and also not as good as Glenn's.

 

I realize I need to make some changes to make my car more like those above.

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James,

 

I would think your setup should have changed after Houston. I mean if you didn't test to get it close to where it was. That was a hell of an impact, and I bet it knocked the suspension around a bit. maybe not?

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he took it to an alignment shop and had it set back to where he had it before the wreck.

 

the changes James speeks of are those that will fix a bad / negative handling trait. turn-in push, apex to track out loose, on throdle push, things like that. all things each of you should know how to resolve w/ set-up changes. getting the car balanced is key.

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James,

 

Did you discover what the problem was that was causing stability issues?

 

on another note I just read the thread over... what was the reasoning behind the rules change in 2004?

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James,

 

Did you discover what the problem was that was causing stability issues?

 

on another note I just read the thread over... what was the reasoning behind the rules change in 2004?

 

I changed to a larger sway bar and it just took a little time to find the feel I was looking for.

 

For Sunday, I changed air pressures and wheel spacers to tighten the car back up from the sway bar change. It was clearly way better on Sunday than Saturday.

 

And like Glenn said..after the wreck it had to go back to the alignment shop...actually twice to get it aligned properly. Luckily the only bent piece was the lower a-frame.

 

Sorry Michael... in typical TX fashion... we can jump a topic off track.

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Sorry Michael... in typical TX fashion... we can jump a topic off track.

No worries James, I'll just make a quick sway bar adjustment for you late Friday night at TWS.

Move along, nothing to see here...

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Michael...Keep in mind that at one point 4th gens were not allowed in the series. When they were brought in, they were brough in very heavy because everyone was afraid they would be class killers. As people got used to the fact that they just werent cleaning up the weight was lowered.

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  • 3 years later...

Man.... I sure hate dragging an 8 page thread up from the dead (even on Halloween) and I only read page 1 and 8 before I did this (and yes, I know I posted all thru it - I've slept since then).

Wondering if anyone figured outthe "hot" Fox spring rate set-up yet. There is a small chance I'll run a Fox Mustang some in 2012 and I'm trying to educate myself some.

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There is a small chance I'll run a Fox Mustang some in 2012 and I'm trying to educate myself some.

 

Glenn,

 

After hearing Robert offering you his car for next season that Sat. night at ECR I had a thought. You could do allot for the series by driving a Fox for a full season. If you go out and win, like you have in the past, then guys should have no issue purchasing a Fox to come race CMC. If you are a mid pack guy in the Fox maybe it needs more help. I don't own a Fox so I do not have a dog in the fight but I really think this would tell us more than anything else about parity in CMC in everything except the S197. I hope you put some real thought into this.

 

JJ

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There is a small chance I'll run a Fox Mustang some in 2012...

 

Awesome. I wish I knew what the "best" springs are for a fox.

 

Try starting at 900/250. That will be real close.

 

 

 

JJ

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There is a small chance I'll run a Fox Mustang some in 2012 and I'm trying to educate myself some.

 

Glenn,

 

After hearing Robert offering you his car for next season that Sat. night at ECR I had a thought. You could do allot for the series by driving a Fox for a full season. If you go out and win, like you have in the past, then guys should have no issue purchasing a Fox to come race CMC. If you are a mid pack guy in the Fox maybe it needs more help. I don't own a Fox so I do not have a dog in the fight but I really think this would tell us more than anything else about parity in CMC in everything except the S197. I hope you put some real thought into this.

 

JJ

 

I wish it was that simple Jerry.

I feel a lot of my success in CMC is in part to my having run a 4th gen on track since 1999. I've never really run anything else in "anger". I have 12 years of seat time in a 4th gen. I have zero in a Fox (Ford for that matter). Surely my driving style has been developed behind the 4th gen, but how does that translate over to the Fox? It may not and take more than a single season to figure out.

I also have the same amount of time learning chassis adjustments for a 4th gen, and once again I have zero in a Fox. Sure you guys would help, but it would not be the same trust level I have w/ myself. I know how much a couple pounds of air in the RR changes the balance, or a wheel spacer add/remove, a front or rear swaybar change. I can relate those changes to a predictable amount of change. W/ a Fox, I'm totally guessing.

So from my perspective, if I go out and run up front, the Fox has the advantage. If I'm mid-pack, they are likely pretty even.

 

If anyone (even experienced drivers) thinks they can just get a CMC car and drop in and race w/ us and not have to go through the "learing curve" of the platform before they do well, they are just kidding themselves.

If said drivers seat time is very limited (in anything), that is a compounding effect.

 

W/ all that said....

Al F is brokering this deal. I've told Al I'll do it, but w/ a few strings attached. I've not heard back from Robert or Al on this issue. I am however not gonna sit back and wait to start gathering data.

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There is a small chance I'll run a Fox Mustang some in 2012...

 

Awesome. I wish I knew what the "best" springs are for a fox.

 

Try starting at 900/250. That will be real close.

 

 

 

JJ

 

What are the OEM rates.

What are typical "street" rates".

 

4th gens are 300'ish F and 115'ish rear OEM (I think). Street lowering springs fall around 600F/185R.

Track rates fall from 700-900F / 225-300R.

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So from my perspective, if I go out and run up front, the Fox has the advantage. If I'm mid-pack, they are likely pretty even.

 

If anyone (even experienced drivers) thinks they can just get a CMC car and drop in and race w/ us and not have to go through the "learing curve" of the platform before they do well, they are just kidding themselves.

If said drivers seat time is very limited (in anything), that is a compounding effect.

 

So the fact that Rob Liebbe (a Fox driver) went to Nationals last year and ran Al's 4th gen and ran up front from day 1 and set the track record means the 4th gen has the advantage?

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So from my perspective, if I go out and run up front, the Fox has the advantage. If I'm mid-pack, they are likely pretty even.

 

If anyone (even experienced drivers) thinks they can just get a CMC car and drop in and race w/ us and not have to go through the "learing curve" of the platform before they do well, they are just kidding themselves.

If said drivers seat time is very limited (in anything), that is a compounding effect.

 

So the fact that Rob Liebbe (a Fox driver) went to Nationals last year and ran Al's 4th gen and ran up front from day 1 and set the track record means the 4th gen has the advantage?

 

I was not going to say that but that is true.

 

I don't want to start a pissing match (since Glenn and I never have pissing matches) but I do hope Glenn drives the Fox, does real well in it, and it shows new guys that they can come racing for very little money in a Fox and do well. I would do this in a second myself but since I drive a car now that is almost exactly like a good Fox race car it would not show much. Also I do not run up front like Glenn does. When I went from a Fox to the SN99 my lap times did not drop much at all. The SN99 feels better at speed but that is about all I noticed. I do know if Glenn does this he will give it all he has and he would be doing a service to all of us in CMC. You will not have trouble going fast in a Fox. That is BS. You are a racer! The set-up stuff......that may be a real killer but as you said we would help all we could and look at the money you could save!

 

JJ

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So from my perspective, if I go out and run up front, the Fox has the advantage. If I'm mid-pack, they are likely pretty even.

 

If anyone (even experienced drivers) thinks they can just get a CMC car and drop in and race w/ us and not have to go through the "learing curve" of the platform before they do well, they are just kidding themselves.

If said drivers seat time is very limited (in anything), that is a compounding effect.

 

So the fact that Rob Liebbe (a Fox driver) went to Nationals last year and ran Al's 4th gen and ran up front from day 1 and set the track record means the 4th gen has the advantage?

 

Remember the whole dyno DQ thing?

 

MM/JJ - I'm trying to keep an open mind. I don't want to place any expectations one way or another. But I have to be ready to understand why I'm not meeting my goals. Is it set-up, driving style, platform.... who knows.

Jerry - I hope your right and I have reached a level where I can just get in anything and be fast. I'm over the winning thing, but I do want a good race.

 

If you guys want this to happen, put your efforts into Robert and not here.

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The dyno thing cost Rob a DQ but the extra power is not the reason he was running where he was. He's a good driver in a good car. Simple as that.

 

JJ

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Awesome. I wish I knew what the "best" springs are for a fox.

 

Spring rates, coupled with swaybar rates, are highly driver dependent. As such, I don't know if there is a "best spring rate", as various drivers like different setups.

 

Try starting at 900/250. That will be real close.

 

Maybe for some, but possibly not for others.

 

I don't want to start a pissing match (since Glenn and I never have pissing matches) but I do hope Glenn drives the Fox, does real well in it, and it shows new guys that they can come racing for very little money in a Fox and do well.

 

Sorry, but building a Fox for "very little money" isn't an accurate statement. Getting the chassis may be cheap (I've found Fox chassis' for free), but to be competitive in CMC, EVERYTHING in the suspension has to be replaced. EVERYTHING - all 6 control arms, bushings, swaybars, struts/shocks, springs, spindles, front and rear brakes, etc. The engine work is considerable, too.

 

I'm not interested in a pissing match either - we each chose our platforms, and have to live with the good, and the bad. I'm simply listing some facts about what it takes to put together a competitive CMC Fox chassis.

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Awesome. I wish I knew what the "best" springs are for a fox.

 

Spring rates, coupled with swaybar rates, are highly driver dependent. As such, I don't know if there is a "best spring rate", as various drivers like different setups.

 

Try starting at 900/250. That will be real close.

 

Maybe for some, but possibly not for others.

 

I don't want to start a pissing match (since Glenn and I never have pissing matches) but I do hope Glenn drives the Fox, does real well in it, and it shows new guys that they can come racing for very little money in a Fox and do well.

 

Sorry, but building a Fox for "very little money" isn't an accurate statement. Getting the chassis may be cheap (I've found Fox chassis' for free), but to be competitive in CMC, EVERYTHING in the suspension has to be replaced. EVERYTHING - all 6 control arms, bushings, swaybars, struts/shocks, springs, spindles, front and rear brakes, etc. The engine work is considerable, too.

 

I'm not interested in a pissing match either - we each chose our platforms, and have to live with the good, and the bad. I'm simply listing some facts about what it takes to put together a competitive CMC Fox chassis.

 

Could some of those facts include spring rates?

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Could some of those facts include spring rates?

 

LOL!

 

I agree with Adam.

 

What didn't come across so well in my prior post was that I wish I knew what the "best" spring rate for a fox is since there really isn't one combination of rates that is "best". I've seen recommended spring rates ranging from 700-1300 in front and 150-350 in the rear. It would be a heck of a lot easier if there was one best rate, or at least a very narrow range of very good rates. It's going to vary wildly depending upon driving style and what the goals are for the chassis. Do you want something that is super stiff to try and minimize the flaws of the crappy Ford design, or are you willing to live with a few of the inherent design flaws in order to have something that is more compliant? JJ's suggestion of starting with 900/250 (or something very close to that) is probably a pretty good one. Just know that there are currently other very successful combinations out there that use much different rates than that.

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Glenn,

 

The motion ratio of the front suspension is approx 25%. The wheel rate is 25% of the spring rate, this varies a little with the different control arm lengths.

 

Some run 900 in the front - approx like running 250 lb/in coilovers.

 

I run a little higher, you have to be careful, the control arms are actually 1800lb/in springs so that skews the actual wheel rates substantially. As well as it making it impossible to approach the wheel rates that a lot of the coilover guys run.

 

The rear is alot more open and greatly depends on what front anti roll bar you run. The poor mans 3 link requires a very different spring rate from normal. The rear motion ratio is around 33% in roll and 50% in heave.

 

-Don

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Awesome. I wish I knew what the "best" springs are for a fox.

 

Spring rates, coupled with swaybar rates, are highly driver dependent. As such, I don't know if there is a "best spring rate", as various drivers like different setups.

 

Try starting at 900/250. That will be real close.

 

Maybe for some, but possibly not for others.

 

I don't want to start a pissing match (since Glenn and I never have pissing matches) but I do hope Glenn drives the Fox, does real well in it, and it shows new guys that they can come racing for very little money in a Fox and do well.

 

Sorry, but building a Fox for "very little money" isn't an accurate statement. Getting the chassis may be cheap (I've found Fox chassis' for free), but to be competitive in CMC, EVERYTHING in the suspension has to be replaced. EVERYTHING - all 6 control arms, bushings, swaybars, struts/shocks, springs, spindles, front and rear brakes, etc. The engine work is considerable, too.

 

I'm not interested in a pissing match either - we each chose our platforms, and have to live with the good, and the bad. I'm simply listing some facts about what it takes to put together a competitive CMC Fox chassis.

 

Adam,

What I was saying is a Fox is an inexpensive way to get into CMC. You are correct about all that has to be replaced but it does not have to be done all at once for a newbe. Remember seat time is worth way more than new rear lower control arms or a PMTL in the first several race weekends. New parts can be purchased as you get faster. If that brings more drivers to the series then I'm all for it. I'm hoping Glenn can prove the Fox is as good a way to go as any (except maybe the S197).

 

 

JJ

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Glenn,

 

The motion ratio of the front suspension is approx 25%. The wheel rate is 25% of the spring rate, this varies a little with the different control arm lengths.

 

Some run 900 in the front - approx like running 250 lb/in coilovers.

 

I run a little higher, you have to be careful, the control arms are actually 1800lb/in springs so that skews the actual wheel rates substantially. As well as it making it impossible to approach the wheel rates that a lot of the coilover guys run.

 

The rear is alot more open and greatly depends on what front anti roll bar you run. The poor mans 3 link requires a very different spring rate from normal. The rear motion ratio is around 33% in roll and 50% in heave.

 

-Don

 

Yes the PMTL does require different rear springs. All but one Mustang in Texas is running the PMTL.

I tried 1000 lb front springs on my Fox (with several different rear rates)but could never get the push out of it.

 

JJ

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EVERYTHING - all 6 control arms, bushings, swaybars, struts/shocks, springs, spindles, front and rear brakes, etc. The engine work is considerable, too.

...

I'm simply listing some facts about what it takes to put together a competitive CMC Fox chassis.

 

I'm ALL ears!!

 

I have an 88 Notch, and yes, very cheap to get started. Overall I haven't put a TON of money into the car. I'm not competitive, but that's me, not the car.

 

I'll share all info about my car... no secrets here. And hopefully we can gain insight to a "decent" set-up.

 

As far as my suspesion goes, right now I have all 6 control arms stock. I did just pick up SN95 A-arms/spindles at the junk yard the other day for around $40. New hubs for about $140 or so, and I’ll be content with the front.

 

As for the back, I plan to replace the lower control arms with tubular aftermarkets and new bushings. And the top control arms can stay the same, but definitely new bushings.

 

Unfortunately I don’t know what bushings for all 4 back arms. I keep thinking how the different bushing materials could add to snap over steer. Most things I’ve read suggest keep the stock rubber bushings in the top control arms on the axle side, and then replace the other 6 attachment points with poly ones. Again, uncertain if there are benefits with different poly designs as far as 3 pieces, or two pieces. I had the 3 piece poly bushings from J&M on my street car (03 V6 Mustang) and shredded those from HPDE.

 

I may have lucked out, can’t say, but I have factory Koni shocks/struts on my car from a Fox SVO. Perhaps they’re the right ones to have, or not. But they’re on and they’re free (so to say).

 

As for springs, I put on at the beginning of this season H&R super race. They make the car feel very stiff, but I’m still trying to learn my driving style, so I’ll keep running them and see how well we mesh together.

 

I haven’t found the engine work to be extensive myself. I have a stock ’89 5.0 engine, put it on a stand and went though the entire thing before installing for the first time. And I haven’t had the infamous Rocky Mountain curse of killing an engine yet. Perhaps time will tell on that one.

 

So when you smart, experienced people figure out the perfect set-up just give me a call!

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