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  #1  
Old 05-08-2004, 01:28 AM
Fig Fig is offline
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Join Date: Aug 2001
Location: Torrance, CA
Posts: 23
Default Coilover suspension question (long)

I have a 37 Plymouth coupe, we took it to the 1/8 mile (Irwindale, CA) last night and it was bouncing both in the front and rear when leaving the line. A little history of the car- this is the third time that the car has been to the strip. The first time with 100 miles on the car it went 7.83 @ 87 mph. The 60' was 1.66. The second time out we advanced the timing to 15 initial, with the extra bottom end it didn't want to hook. It finally hooked up, when it did it ripped the three link brackets from the 9" housing (the first 1/2" of weld didn't penetrate). The rear wrapped up enough to take out the driveshaft, We put a new currie housing and made new brackets. Now the car porpoises with the best 60" of 1.76, The car went a 7.72 @ 90 mph. The car has a three link, mustang II front suspension with Alden coil over shocks all the way around. Now the question- Do you need to set "sag" on the shocks like you do a motorcycle? The shocks have damping adjusting knobs. The rear suspension seems bouncy on the street. Where do I start to isolate the problem. The problem started after we replaced the housing and brackets. I think that we adjusted the rear coilovers to adjust for ride height. I tried to call Alden this afternoon but they close early on Fridays. I think the extra bottom end and MPH came from having fourseconds flat recurve my distributor. (thanks Don)

Sorry for the long post and thanks for the help,
Allen

The car:
Weight 3350 lbs. with driver
Engine size: 440+.060
Automatic 727
Rear end ratio: 4:10 (ford 9")
Tire diameter: 29.5 (BFG Drag Radials 315/60/15)
Manifold type: TM7
Carburetor: Holley 850
Fuel Pump Size and type: Holley blue
Fuel lines: 1/2" braided
Regulator type: Holley that comes with the blue pump
Idle RPM: 950 neutral- 850 in gear
Current initial timing: 15 degrees
Current max timing: 35 degrees
Head type and valve size: 906 with mild port 2.14 intakes 88cc's-89cc's
Cam duration at 50: Intake 230 Exhaust 238
Cam lift: Intake 515 Exhaust 536
Cam brand: Hughes
Hydraulic HE3038 (2 degrees advanced)
Compression ratio: 9.9 flat tops (trw six-pack pistons)(true 9.9 pistons stick out of the hole .006 (yes I screwed up))
Fuel Octane level: 91 (crappy premium in Ca.)
Convertor stall: 3000
Convertor type: Continental 11"
Elevation: 300'

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Old 05-09-2004, 04:46 PM
jmdrace jmdrace is offline
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Location: petersburg,new jersey
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fig... you say coil overs on all 4 ok what is the spring ex.(225) on each wheel and what shock valving at each wheel and what is the shock travel and lenght.i wont ask do you have a set of scales?what is the pinoin anlgle?
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Old 05-09-2004, 04:54 PM
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MoparMarcIdaho MoparMarcIdaho is offline
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Age: 67
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Arrow you need better weight transfer

so looser would be better at the strip,dampening way down and sandbag the rumble seat area.Or not.
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Old 05-09-2004, 07:09 PM
Fig Fig is offline
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The spring rate is 300# on the rear and I don't know what the front springs are. I'll get the paint code off of the springs and check with Alden tomorrow to verify the front springs. I noticed that the rear of the car was extremely loose (not enough coil pressure on the shocks). I have taken the adjustment to almost 1/2 way of the threads. My son and I are making some bump stops right now so the shock does not bottom out. I will have the car off the jack stands in a 1/2 hour. The damping on the rear is all the way soft. I'm think that the problem is the spring set up.

Thanks for the replies, the sandbags sound like a good idea as long as the tech inspectors didn't find them.

Thanks,

Allen
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Old 05-09-2004, 07:11 PM
Fig Fig is offline
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I missed a couple of questions_

I think the shocks are 14" eyelet to eyelet, thee inches of travel.

Thanks again.
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Old 05-09-2004, 07:12 PM
Fig Fig is offline
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O.K., Just call me slow. The pinon angle is -2 degrees.

Thanks
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Old 05-09-2004, 09:18 PM
jmdrace jmdrace is offline
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fig the rear springs have etchings and a tag on them should be at ether end. also measure the free height of spring ex 12inch then set up on car with out shocks hooked amd remeasure spring a guestamate you should loose aprox 2 inches.this car must be tail heavy to have 300lb springs but may need more.for the front its the same look at the ends for the etching and or tag.this should be around 450 to 600lb depends on set back of engine.if over axle may need more.the rear pinion angle with nose down 5 degrees.also when setting up make sure the cone height has not got the shock streched all way or out of stroke .usually 3 inces on street is ok .when you hook all up with out shocks care fully on the bumper bounce the car .if bounces to much you may need more spring and then dial the shock to the lighter setting provided they work.or if seems stiff use the lighter setting on the shock dial.this may cure your front hop also.rememeber the 2 inches you loose is preload .
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Old 05-09-2004, 11:08 PM
Fig Fig is offline
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JMDRACE,

Thanks for the help. Tuesday night I will be able to play with the car and do what you suggested.

I'll udate once I make the checks/changes

Thanks,

Allen
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