Compression Test on 24 Hours of Lemons 200-6

turbo2256b":33i18vcb said:
The predecessor to the 256GT would easily go around a 90* corner at an intersection over 60 MPH.
What springs are you running front and rear? There was a chassis flex issue with that model found racing them years ago in the front end. Still have a kit offered to remedy it.

Friends and I ran a 6cyl Gremlin for a few years in circle track won overall 2 years before they figured how to factor us out.

Learned long ago if you got something that can walk all over the competition your best off winning by a few feet than a mile.

I am running a stock front sway bar, 3/4" Mustang rear bar. Front springs are from a 5.0 Thunderbird (stiffest Fox chassis springs according to Moog) with 1 1/2 coils cut off and a solid spring rubber in them. Rear springs are also Thunderbird, same as Fairmont wagon, with coils cut as well, don't remember how many. At Buttonwillow there were several sweepers that were about 180 degrees taken at a decent rate of speed, but our oil pressure stayed steady.
 
Front I am running 70ish coils from a 429/460 torino cut 1 1/3 coils about 720 lb rate. Looking at handling lowering coils for a Fox mustang I had free ht was only about 1/4 inch shorter. ID and OD was the same.
Do you have any idea what the rate for the Tbird springs were before cutting?
 
turbo2256b":1t79b2ct said:
Front I am running 70ish coils from a 429/460 torino cut 1 1/3 coils about 720 lb rate. Looking at handling lowering coils for a Fox mustang I had free ht was only about 1/4 inch shorter. ID and OD was the same.
Do you have any idea what the rate for the Tbird springs were before cutting?

According to Moog the LTD LX had a 415lb/in a Thunderbird Turbo, or V8 with AC had a 462lb/in. The rear from the wagon, Thunderbird or Cougar is only 249lb/in.

You can look up Moog specs on this site: http://www.moog-suspension-parts.com/pr ... =MOOG-8599
and check cross references via Amazon.com of all places: http://www.amazon.com/Moog-8599-Constan ... B000C57U24 (click see all vehicles this fits)

Someone on the Early Fox Body Forum looked them up at some point.
http://vb.foureyedpride.com/showthread.php?t=74794
 
"...My father keep pitching the 250 at me too, but I told him there is barely enough hood clearance for the 200 and the 250 is taller. Plus I'd have to replace the C4 transmission..."
"...remember the motor mounts on that chassis but used motor mounts from a 170 Facon on my 70 to move the engine back 1 1/2 or 2 inches. 250 weighs almost as much as a 302 think about 20lbs lighter..."

I am not a racer C my rig below (or mechanic) but have listened to those on here -

The 250 is a stroked 200 (more tq, don't know if U need that in this style race) cubes = more hp too. It weigh 460 lbs. To lower it U can 'slot' the towers (not the mounts - some use the mavrick I6's mounts as well).

The C4 fits (they have SBF bell) & is great due to bein the auto to rob the least power.
 
chad":1uyil8py said:
I am not a racer C my rig below (or mechanic) but have listened to those on here -

The 250 is a stroked 200 (more tq, don't know if U need that in this style race) cubes = more hp too. It weigh 460 lbs. To lower it U can 'slot' the towers (not the mounts - some use the Maverick I6's mounts as well).

The C4 fits (they have SBF bell) & is great due to being the auto to rob the least power.

My C4 does not have the small block Ford Pattern, it has the small six pattern. To put it behind a C4 would require changing out the bell housing to the larger one at the very least. The other major consideration is that it is much easier to find a running 200 on Craigslist for $200-300. We aren't planning on blowing up a lot of motors, but I do want to have a back up plan should we need to swap motors on race weekend and find one locally.

Sure an extra 20% displacement would be great, but since all these motors have to breath through the same 1 3/4" hole in a cast iron log I seriously doubt I would end up with any more power in the end. Sure the 250 would have more bottom end, but I think it would run out of breath sooner.
 
turbo2256b":31ttg6mr said:
This might help selection of better springs. I would possibly go for the 680s front, 170s rear.
http://www.allfordmustangs.com/Detailed/54.shtml
How are your rear control arms set up?

What shocks?

I don't know where you are measuring your front spring numbers, but 6-700lb/in you might as well not have any front travel at all.

The rear is stock control arms, but why would I want to go to such a soft rear spring like a 170lb/in?

My understanding is that a too stiff front end leads to understeer, same as a too soft rear.
 
Not all that shure about the 170 spring in the rear either. My Fox Mustang had 2 step rear colil overs. 400 lbs compession 146 upward. They are not made anymore. Had like the 680s in the front cornered great. Maybe the 225s (was it) would work better for you. Seens I remember a lot of serious fox racers use closer to that.

Senero my 87 Grand Marquis. Aprox 4000 lbs. 2500 front, rear 1500 aprox weights but within 100lbs or so. I autocross this car and its realy set up for open track. Front springs are 1000# and the rear are 350#. Last time out at the autocross M3s, 370Zs and a Boxter's were 4 seconds slower. Its also my daily driver, drag, show car. I started out with 1000s in the front rear mabe 160s. went from that to 180 to 225 to 250 then jumped to 350. The 350s might be better for autocrossing than the open track but were much better than 250s either venue.
I used the rear spring to dial in the amout of over under steer I perfer. I like neutral to slight over steer.
Next i will be working on a watts link and a 3 piece splined rear sway bar then front. This could change my spring pressures a lot. If my far future plans are iplemented I will move the body and engine back 10" on the frame moving the front and rear axles forward for a better weigh distribution. Kinda losses the back seat.

70 mustang is 720 front springs (used with 200 and 250 engines) rear 225 leaf springs (different than rear coil sus).
Probably close to the weigh of your car. Best handling car I ever built for me.

I think you stated 425# for the rear of a waggon. Something dosent make sence to me there as my waggon oveload springs I once used in my grand marquis from a colony park full size waggon were like 190# or so.
 
No the rears are all about 200-250lbs/in. Of course you can't compare between chassis because there is the variable of the length of the arm the spring is acting on. For the rear end to more 2" the rear spring only has to compress like 1" on a car with spring mounted trailing arms. Not sure how much of a lever arm the fox body has on the front, between the spring cup and the ball joint, where the actual motion would be measured. I imagine it is closer to 1:1, since the A-arm is shorter than the trailing arm, and the spring is closer to the center where you would measure the motion
 
This is what was in my Fox chassis:


My Fox Mustang had 2 step rear colil overs. 400 lbs compession 146 upward. They are not made anymore. Had like the 680s in the front cornered great. Maybe the 225s (was it) would work better for you. Seens I remember a lot of serious fox racers use closer to that.

The fronts would have been converted to coil overs with stiffer springs but traded the car for half the down payment on a 48,000 boat. It was a 84 Mustang is it all that different from a Fairmont.
 
turbo2256b":16ocvxjr said:
This is what was in my Fox chassis:


My Fox Mustang had 2 step rear coil overs. 400 lbs compression 146 upward. They are not made anymore. Had like the 680s in the front cornered great. Maybe the 225s (was it) would work better for you. Seems I remember a lot of serious fox racers use closer to that.

The fronts would have been converted to coil overs with stiffer springs but traded the car for half the down payment on a 48,000 boat. It was a 84 Mustang is it all that different from a Fairmont.

Yes the 1984 Mustang is nearly identical to the 79 Fairmont. The difference is you are comparing coil over rates to the rates I was quoting for stock chassis set ups. You can't do that. Coil overs act directly, while the stock springs lever against the lower control arms, and the A-arm in front multiplying the spring rate.
 
Trying to get over is what I did with front spring rates. Realize it would be to costly for coilovers in the rear and the 2 step coilovers from Carrea are no longer available since they were bought up by QA1. I have had discussions wiith QA1s owner about making the parts to do what Carrea had with the 2 step but claim the double adjustable coil overs do the same thing. I think not though, combination of the double adj and the 2 stepp springs would be killer in my book.

So I would try the stiffer springs in the front and try different rears to dial in how you perfer steer understeer, oversteer or neutral steer. Some tracks one or the other might do better depending on how tight the turns are etc.
I do know the rear suspension set up on the Fox chassis is the weakness do to arm location.
 
I do rear suspension calibration and mobile ignition, carb, EFI and transmission system calibration for a living with XEC Ltd in Dunedin NZ. I currently have two Mays Meter systems operative, one in my Independent Rear Suspension 1996 RAV4, and the other in my Live axle 1982 Mustang. Both vehicles run similar wheel bases and tracks, and I've already done a huge amount of IRS to live axle research from the Brock Holden Commodore days, where Corvette and BTR centred 1984 to 1988 German Opel Monza IRS systems were trialed. The difference in semitrailing arm IRS verses Five bar Live axle handling and ride was similar to the SN95 Cobra IRS verses the Quadrashock Mustang set-up.



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They each run a Campbell Scientific 16 bit datalogger which picks up total upward bump every 64 feet of vehicle movement. I'm busy downloading some other RwdS data for the EFI section at the moment, so can't show you my completed X.C.T.A.S.Y. RAV4 or ITZ OLD Mustang system just yet. Only just finished building them.

The development was charted in the Hardcore section, under the ITZOLD and XPLODE Road Roughness posts.

These devices measure the results of vehicle skid pan acceleration, and left and right wheel path movement at the shocks lower mount. It's all calibrated to the World Bank/ US based International Ride Index, basically a standard General Motors Proving ground system. I have five Laser Profilometer calibrated strips on public roads in Otago, New Zealand, plus have access to the Levels (Timaru) and Teratonga (Invercargill) race circuits, where cars like the 1984 Pine Pac Fox 5.0 GT Mustangs were raced. See http://www.nzmustang.com/history/racecars/pinepac1.htm

My certification engineer is Roy Macdonald from Roy Macdonald Automotive in Dunedin, and he does the suspension and engine servicing on one of the the ex Dick Johnson Group A Mustangs in the website above.

Whats been found is that the factory four link live axle Fox chassis is reasonable if not over loaded on uphill sections. Dick Johnson attests to that on his DJR website. Race cars here didn't use QuadraShock, only German Atlas or Ford 9" diffs with dual shockers.

The International Ride Index on a calcined bauxite surface, or recycled foamed bitumen, asphaltic cement, stone mastic ashpalt or open graded porus emulsion circuit is so low and smooth, that racing situations, in sub 135 mph situations, live axle suspensions are not at much disadvantage to IRS. Above that, like on NASCAR, a suppled srung IRS is still not a major advantage. On Aussie AVESCO circuits, maybee

Any time suspension bumps are non linear, an irs system prevents sway and bump steer, roll over steer and reverse squat from hurting you steering. The tendancy these days is to stiffen the spring in small degrees based on your needs, and then make the shock dampen out the rest. On early FISA/FIA Group 2 and then later Group N race cars, the stiffest spring wasn't allowed to be stiff enough, and so you'd make your old Bilstens or Konis do the work to compensate. You'd find that the BMW idea of a soft spring and a stiff damper would work best, but in that scenario, the shocks can fade over the race, so siffening the spring generally take pressure of the damper (shockie)

These days, your probably better off running close to the stiffest spring you can find, and running the best damper you can get. The stabilizer/anti sway/anti roll bar takes care of roll stiffness, and the spring and shock combo takes care of limiting bump steer you see at the front.

For the Fox Mustang, Ford raised the back edge of the bonnet plenumb an inch, shortened wheel base 5.118", and cut the tail back, so they behave differently on a circuit, but what works on a Stang works on the 'Mont.
 
The Fox live axle cars because of upper and lower arm piviot points (and space to work with) are not well located. They have a tendancy to pull the tires off the pavment. Under acceleration suspension needs to extend easier and under deceleration compresson needs to be stiffer. Unless one changes the piviot points / arm lengths.
The two step system imensly improve my 84 Mustang. The 400# springs would help it dive way further into the corners. The combined rate of the 400# spring and the I think 225# (would have to dig up my notes) spring on extention would give a rate of 136# on extension.
As you have stated about shocks being dampers. The double adjustable shocks with the 2 step springing would have even been better because the damining of the extension spring rate and compression spring rate could have been optomized better. Think I had 50/50 Konis at the time.

Heavy springs and properly dampening shocks the ride can be better than light springs and real stiff shocks and will out handle the real stiff shock light spring setup.

Now if one were to go with say like the 3 pice splined end 1 1/2 to 2" dia swaybars spring/ dampining rates can be reduced because roll is then more controled by the bar not the spring. Hope to go this way on my 87 Grand Marquis in the near future. But is down on the list at the moment.
One thing I have found Is it likes stiffer extension on the front shocks than compression and the rear stiffer compression than extension.
 
Aha. Gotcha. Certainly sounds like the very best option. We used that and a correction kit, which is not legal in your sub Group 2 classes. It seams to me that every problem with Foxes can be TOTALLY sorted with defunct parts and aftermarket knowledge.

For Australian Touring Cars, we used what we called variable rate springs and a 'correction kit' to try and sort out the Watts Link Falcon coil spring system in Group 3/Group C sedan racers, and later Fords till 2003 used this system. Both our Aussie X, E and A shells from XE onwards till the last AU and all your S shells from 1978 untill the IRS Cobra 4.6 suffer the same problem; that the lower link is longer than the top, and consequntly, its always push push undesteer on entry, loose over steer on exit, a standard four link problem. On little Jappers, they angled the top arms in more, and tried to shortern the lower arm to compensate, but there is a limit top what you can do . Slapper bars help windup on the 1982 5.0 GT, but a Panahrd rod or a Watts Link doesn't help mutch as the problem is the top arms need to match the bottoms for length to correct the geometry. Instead of correcting it, variable rate spring tension creates a fake (pseudo) geometric change under droop and bump.
The racing versions of the torque tube Holden Gemini (Isuzu's Piazza/ Opel Kaddet/ Vauxhall & Chev Chevette based rear driver ) used to have its standard pick up points kept, but the lower arm given a secondary pivot which altered things in a way that effectively equalized the top and bottom arm lengths, and this would help.

For FISA approved Group A Mustangs, we just put rod ends on everything and fabricated uper link parts to suit the length of the bottom arms. This is the homologation ZF Atlas diff from a Cortina/Taunus station wagon, a 7.5" spool or Detriot Locker. The Ford Motorsport guy Karl Krafuss was German, and he used Ford of Europe RS 2000 Escort and RS 2600/3100/3400 Capri circuit racing parts to get the first 5 liter Fox Stangs compliant with the Group A regs, and diffs were a free item. See how the upper arms look?

 
The idea behind the angles of the upper and lower arms from the top view is to create a binding action to help with centering the axle left to right. If they were straight a track bar or watts link would be required to keep alignment side to side. This would add cost to a production vehicle as well as require more space. The angled arms also need rubber bushings to absorb the binding action. Better handling can be had by installing urathane bushings but not at all piviot points. Ends in the 4 lower arms could be done with hard bushings uppers soft or vice versa. or the front pivots uper and lower hard and rear upper and lowers soft. If it isnt done this way rear will be in such a bind it will screw with travel.

Longer arms with the intersecting pint in the front as close as possible to the front U joint would be my preferance either in a 4 or 3 link system arms parallel as vewed from above. Watts link and splined shaft sway bar woud be sweet. Some extra holes to position control arms to adjust dive antidive for differing conditions.
 
The system cannot be economically changed for TFHL, so it seems to me that optimization with the best springs you suggest is best. Our 1982 on wards Falcons used triple rate coil springs, just like what you suggest.

The Fox chassis copied Cortina/Taunus T-shell geometry, and angled its arms to partially double Panhard rod or 'Watts link' or tie the axle for lateral location.

On a 390 hp Group A GT 5.0, only changes were fabricated arms, but the upper arms were reworked to stop roll steer, longer via that complicated linakge and a full floater 9" diff and disc brakes.



As an aside...

X, E and A body Live axle Falcons, copied in some Panther and some version of the S 197 chassis. Major handling problems on the circuit with this set up could only be fixed with double jointing the lower arms or major changes of upper arm length. When Watts links were used on Escorts and Falcons, both bars were almost parallel. For sedan racing, the lower link was often reduced for length to get closer to the shorter top, and the Watts link was reversed on most of the the Group 3 racers. With a 500 hp 351c, these were a real handfull untill these mods were made.



By 1993, on Australian Vee Eight Super Car set ups, they made the upper control arms travel up into where the rear seat would have been, so the system was now superbly stable, but impractical unless you don't like your passengers. Shades of the 350 GT-R Shelby set up.

In a similar way, the Zakspeed Escorts made the Watts link work. Zakspeed was helped along by Mike Kranefuss, later of Ford Motorsport. The homologated parts were used in BDA IMSA Mustangs. The lower and upper links in these little Escorts were the same length. Ford Australia undid the some of the good work by making the top arm shorter, when it should have been angled in to create more upper control arm length. See the 600 hp capable ZF Atlas diff again...

http://img97.imageshack.us/img97/4777/img2122zw6.jpg
 
Reminds me the toothed rubber bushings in the front and rear control arms. One way or another I disable them so they dont bite in the mounting and and screw with suspension movement.
 
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