Here's a video of my coupe launching. I have double adjustable afco shocks on all four corners. It is a manual transmission. Bias ply DOT slicks. Based on the video, what can I do with the shocks?
[img]http://i.imgur.com/boeexFms.jpg[/img] 31 Plymouth Coupe, 392 Hemi, T56 magnum RS23J71 RS27J77 RP23J71 RO23J71 WM21J8A I don't regret the things I've done. I only regret the things I didn't do. "Wise men talk because they have something to say; fools because they have to say something. ~ Plato"
Re: Shock adjustment help needed, launch video
[Re: Hemi_Joel]
#3209410 01/31/2406:08 AM01/31/2406:08 AM
Joel, from what i can see, i think the rear axle is extending extremely fast, hitting the end of the shock travel, rebounding and repeating all in about 5 to seven feet. If you can stiffen extension, i would be tempted to go extremely stiff, maybe starting as tight as possible. Also i would drop the launch rpm if you can some. If your suspension has a high and short instant center, that might be part of the problem.
Like stated if you put the video on You Tube it can be slowed down and stopped at spots for a more in depth look. I agree on tightening the rear. Both rebound and compression. The front has very little travel but tighten up the rebound there as well. Once the bounce is corrected it needs some wheel speed. Not being a stick guy my thought is raising the rpm at the start will allow that adjustment.. Doug
Re: Shock adjustment help needed, launch video
[Re: dvw]
#3209478 01/31/2401:09 PM01/31/2401:09 PM
I’m def not a chassis guy, but it seems to me that fundamentally it’s going to be hard to keep the suspension loaded properly when it sounds like there is an “almost” bog after you leave. In my mind I’m thinking there is some relaxing of the suspension when that happens.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
Re: Shock adjustment help needed, launch video
[Re: Al_Alguire]
#3209567 01/31/2404:40 PM01/31/2404:40 PM
Now that I can watch in slow motion. The rear looks to have no seperation (even squats a tad) but still appears to dead hook until it bounces. Also no wheel speed. My first thoughts woukd be it needs more rpm and less tire pressure to gain wheel speed. But the underlying problem may be a bog leading to the above issues. Not sure I'd worry much about the front until the rear is fixed. Doug
Re: Shock adjustment help needed, launch video
[Re: dvw]
#3209674 01/31/2410:52 PM01/31/2410:52 PM
Thanks for all the input. So if it has no separation would tightening the extension help it or hurt it? As far as the bog, there's nothing I can do about that for tomorrow's race. So I'll just have to live with that.
[img]http://i.imgur.com/boeexFms.jpg[/img] 31 Plymouth Coupe, 392 Hemi, T56 magnum RS23J71 RS27J77 RP23J71 RO23J71 WM21J8A I don't regret the things I've done. I only regret the things I didn't do. "Wise men talk because they have something to say; fools because they have to say something. ~ Plato"
Re: Shock adjustment help needed, launch video
[Re: Hemi_Joel]
#3209690 02/01/2412:17 AM02/01/2412:17 AM
I would say yes as it may reduce the bounce back after the hit. It may like a looser comp setting to aloow it to squat. That might give it some wheel speed. It's possible the 4 link is way off as well. Doug
Last edited by dvw; 02/01/2412:22 AM.
Re: Shock adjustment help needed, launch video
[Re: Hemi_Joel]
#3209696 02/01/2412:57 AM02/01/2412:57 AM
Try stiffening all four up as stiff as you can them and the see what that does and go from their It may only need the rear only stiffer, tighter, but I would do both and then if that helps start softening the fronts a little bit at a time until you like it one way or the other
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: Shock adjustment help needed, launch video
[Re: Blusmbl]
#3209707 02/01/2408:15 AM02/01/2408:15 AM
Very little suspension change front or rear in that video, everything looks way too stiff but then again I'm a Caltrac guy. How much travel does it have front and rear ? are you topping stuff out or reaching the limits of the suspension ? I know it sucks to have to use a race meeting for test and tune but I'd go looser on ext front and rear and see how the car reacts.
'74 Challenger..9.46 @ 145.9 1/4, 6.001 @ 118 1/8 so far. 4023lb !!! # N/A, Marsh performance 655ci, Indy Maxx, T/R, Indy 600-13 X's, Street legal, pump gas, full interior, Cal-Tracs, mufflers, 3:73's and real 10.5 radials. 9.51 @ 142.4 1/4, 6.003 @ 114 1/8 with our old mule KB, 572-13, 580 wedge. RHD '68 Barracuda Fastback 323ci street/strip. Best ET 13.88 @ 99.03
Re: Shock adjustment help needed, launch video
[Re: Tig]
#3209717 02/01/2409:59 AM02/01/2409:59 AM
One thing to consider is these tracks are super tight from what I have seen this week. I think that is one reason Lutz in his pro mod has had a hard time getting down and is 2nd overall to a Coyote Powered mustang on a drag radial(6.29!) Some of the stick cars are running radials now as well.
Joel you might need to loosen the clutch up some to get the bog out, the wheel speed might be hard to come by with the tight tracks. A torque converter would also be a good solution and it would get that pesky stick out of the way
Last edited by Bad340fish; 02/01/2410:05 AM.
68 Barracuda Formula S 340
Re: Shock adjustment help needed, launch video
[Re: Bad340fish]
#3209753 02/01/2412:18 PM02/01/2412:18 PM
I would agree stiffen the extension. Not suspension but what weight flywheel do you have? Many years ago 1980's I raced an Anglia with a four link, four speed, and it weighed 2,200 lbs with me in it. Ran low 10's high 9's Had a 30 lb flywheel in it, put a 15 lb wheel in it and it was so much easier to launch and drive. Light car does not need all the torque multiplication of a heavy flywheel.
Re: Shock adjustment help needed, launch video
[Re: JERICOGTX]
#3209764 02/01/2401:34 PM02/01/2401:34 PM