launch video of my f100 the other weekend>>> Made some progress

Truck is still on leaf springs with homemade adjustable ladder bars and the shocks are relocated behind the rear axle. Hopefully you guys can disect the video. I don't think I have the software to view the video frame by frame, or I'm just too computer illerate to figure out how to do it. Looking for suggestions/advice on what to change/try. I think I need to slow down the shock extension or lengthen the bars. Also wondering how much shock travel I should have on the front and rear? I have comp engineering 90/10 shocks on the front and some cheap shocks I found laying around the shop on the rear. Lets see if I can link the video.

good dbl. adj.shocks are the best thing you can do to a ladder bar setup.your hitting the tire hard,good shocks will help it and get the frontend up more and help 60'too.

With my windows media player after starting a video you right click on the video screen and an options window opens. Go to "enhancements" and a second window will open, go to and click on "play speed settings" in the second window. This will open a small rectangular window with 2 round forward/back play speed buttons at the top left & 2 square foward/back frame by frame advance buttons in the center. Usually (for me anyway) the foward frame step button works good with most any video format (mpg, wmv, vob, dvd, etc), but the back step button isn't as reliable.

You could also download "media player classic-home cinema" & it's updated codic pack. It looks like it's the old original windows media player that has been revamped & upgraded. The best thing is it has a frame by frame step button right on the face of the player. It plays most video formats including the flash flv formats that youtube converts most videos to. But it can sometimes have problems with the mpg/mpeg video format.




It looks to me like the truck dead-hooked 100% on the initial hit, then did a super short "hop-skip" spin for a split second as the sidewalls un-wound & threw the rims/housing back up-in the air unloading the slicks ever so slightly. But after the short "hop-skip" it went right back to a dead-hook. Because it's initially hammering the rim deep into the sidewall the suspension might be hitting the tire a little too hard resulting in the bounce back-up the other way. But it might also be because you might not be running enough air pressure, they did look a little low.

You might try messing with the air pressure first to see what effect it has on the slight hook-skip. Then move on to tightening the rear shock extension valving little by little (if possible) each pass.

he^^^knows suspension! i had a bad tire gauge a while back,showed some video on here and the first thing he asked was tire psi.i had 11 and thought i had 7.lol. he picked it out and had other good advice that got me hooked up and goen.thanks Dave!

cool40 wrote:he^^^knows suspension! i had a bad tire gauge a while back,showed some video on here and the first thing he asked was tire psi.i had 11 and thought i had 7.lol. he picked it out and had other good advice that got me hooked up and goen.thanks Dave!

Good up close launch video shot at a correct angle slowed way down (or frame by frame) is just such an amazing "tuning" tool to work with, lets you see all the stuff that your eye/brain misses at full speed. Only thing better is slowed down launch video that was shot at higher shutter speeds, that shit can be mind blowing showing even more of what all is going on during the launch.

DILLIGASDAVE wrote:

cool40 wrote:he^^^knows suspension! i had a bad tire gauge a while back,showed some video on here and the first thing he asked was tire psi.i had 11 and thought i had 7.lol. he picked it out and had other good advice that got me hooked up and goen.thanks Dave!

Good up close launch video shot at a correct angle slowed way down (or frame by frame) is just such an amazing "tuning" tool to work with, lets you see all the stuff that your eye/brain misses at full speed. Only thing better is slowed down launch video that was shot at higher shutter speeds, that shit can be mind blowing showing even more of what all is going on during the launch.

some of the tire shake vids you posted a few weeks ago were unreal.lol.

When this video was taken i was running 14.5 psi cold, same setting that i used when foot braking. two weeks ago i tried 15.5 psi and i didnt hear the chirp in the cab as much. I assume this hop/skip is causing that noise. I was told the front tires also left the ground on two of my passes two weeks ago and i guess that would explain the steering wheel shake i experienced after letting go of the transbrake button. Last week I lengthened the bars 2 inches and the truck didnt seem to lift the front as much. I think i'm going to go back to the shorter bar setting and i just ordered some new rear shocks and I'm also going to put tubes in the slicks since they are over a year old and they arent holding air for very long anymore . The tires are 29-10.5W-15 hoosier stiff sidewall. Thanks for the replys guys.

Anybody ever went from not running tubes to running tubes? Did going to tubes change what air pressure the vehicle liked? Just trying to get all my ducks in a row since i've never run tubes before and i only get two time runs saturday to figure out these new shocks and tubes. Thanks again

i went from tubes to tubeless with stiff wall but the "working"psi did'nt change any.the tubes in stiffwalls should help you out.if you can get the separation in the rear suspension slowed down with stiff shocks the frontend will rise more as weight shift will improve.

well Its been a while and I think I have made some more progress along with wrecking a rearend case, gears, transmission tailhousing, and drive shaft, lol. Anyway, I found on my laptop that I have windows movie maker, so I played around with it yesterday and made a short video of the truck from some video my friends shot a few weeks ago before everything broke. This is with new rear rancho rear shocks and a new rear leaf spring in each side of the spring pack. I also went to a 4.56 gear from 3.70 to see if I could get the truck to react quicker because my reaction times have been slow since I started using the transbrake. Let me know what you guys think. The link to the youtube video

looken good! the transbrake will show you a weak link!lol

The first pass on the new video (shot from the driver side) looked like it was still hitting the tire pretty hard. But unlike the original video this time it stayed pretty much dead-hooked after the initial hit (no hop/skip/spin). The other passes shot from the passenger side were a lot harder to see what was going on because of less light/more shade. I think the last pass might have had a very slight hop/skip, but it's hard to be 100% sure how much might have happened (youtube video compression doesn't help either lol). How tight/loose was the rear shock extension/compression valving set. You might also see what effect limiting the front suspension travel a slight amount might have on the launch.

I had the rear shocks set in the #5 position. This was the first day I had these shocks on the truck. There are 9 settings. I believe the lower the number the less resistance the shocks have (rebound faster)?? The shocks are rancho brand.

I was told by more than one person that the track was going away as the day went on as their car's 60fts were falling off too. The first pass on the video was a new best 60ft for the truck at WIR. I made the video in the same order the passes were recorded. I believe dave is correct that the last pass did show the hop skip deal again as I remember hearing the chirp in the truck on that pass.

I'm running 15 psi. of air and I'm wondering if I should go up to 15.5 or 16 now that I see how close the rim is getting to the track. So far 15 seems to be the best though as I've tried 16 psi but with the track not being consistant between passes its hard to tell what works best.

I was thinking about making my own shock mounts for the front to limit the travel an inch or two. I'm not sure if its a step in the right direction or not though.

Thanks for the help guys

Cody with that much air it's wild how much your slick wadded up. You weren't kidding about the rim getting close to pavement.
I'm running 8psi in my 29.5x10.5 non W hoosiers. I hope they don't wad up like yours did in the video . Gonna go try to slomo some of my vids and see.

How was the trucks 60ft with the 4.56 gears?
mike

mike... The best 60ft the truck has done at WIR, my home track, is 1.76 with the 3.70 gears and it did a 1.72 with 4.56's before it spit the pinion out. That 1.72 60ft. Is the first launch in this second video. When i was at US 131 in martin michigan for the ihra team bracket finals the 60ft improved again to a 1.67 only difference being the track and I think the air was a little better. I never thought the truck would 60ft. that well with only a 390 for motivation. Although I am leaving the line with the throttle wide open against the converter

Truck did a new best last saturday. The weather was great and the track was hooking better than ever this morning. Went away after the sun came out though, don't understand why that is? Was only 65 degrees midday. First pass video if the link works.

https://www.facebook.com/#!/video/video.php?v=2295183573485

That's probably the best looking launch vid so far. Just make sure the dead-hook/converter/gear combo isn't lugging the engine down slowing the rpm climb.

DILLIGASDAVE wrote:That's probably the best looking launch vid so far. Just make sure the dead-hook/converter/gear combo isn't lugging the engine down slowing the rpm climb.

Dave, I wonder if I'm lugging down the motor slightly after the hit and that is what is causing the hop skip? When the air is really good for making power seems to be when the truck leaves the best and the front end sets down slower and smoother than when I can hear the hop/skip/tire chirp in the cab. I suppose my little pump gas motor, with only 4200 stall, and a heavy vehicle, this is a likely possibility? Guess I need more cowbell or some Mr. Frosty, lol.

Yes, lugging an engine during the launch can be one (of many) possible cause for a hop/skip.

That's why some cars can get away with a 100% dead-hook launch, & some need some given amount of controlled wheelspeed/slippage/spin during the launch. It's possible that on days where the air is good, you're making just enough more power to avoid a possible minor engine lug/pull down/power sag during a dead-hook.

Taken to it's extreme (like the big, big power cars) having too much initial hook for a given amount of available "at launch" torque/power can force things to blast past a simple "hop/skip" up to one of the many different forms of violent, teeth chattering, eye ball blurring tire shake.