Using suspension video

[dvw]

I've talked about getting video for suspension diagnosis. I've seen many from the rear, full speed, or too far away. This is an example of what you need. This was taken with a cell phone in slow motion. The main focus is on the rear tire close in from the side. Secondary you can watch the front suspension as well. As discussed earlier some cars need the rear to squat. Some need to rise. But I still subscribe to lifting the front slowly. You may need more or less front travel, but not travel that is too quick. In this video the car is set to dead hook for index racing. Tightening it up would probably make it even quicker (in fact it is quicker on a less prepped surface). So get out there and use video to your advantage.
Doug

 

[doublekrossd]

cool vid, I've seen a few over the last year or so that I'm trying to learn from. one was really informative that went on for quite a while and detailed what was changed and what the differences were that the changes made. I've got some traction issues with mine, I'm SLOWLY learning. Is that your car? very nice looking!

 

[BeepBeepRR]

Man that looks bad ***..

 

[33 IMP]

Doug, is that slo-mo from an i-phone?

 

[Budnicks]

Thanks Doug

 

[dvw]

Yes, my car taken from a Samsung phone. Dead hook like this 1.30 60ft. With a little slip and wheel speed 1.25 60ft.
Doug

 

[69roadr]

What kind of horsepower does it take to lift the front wheels off the ground?

 

[Mike67]

Beautiful car Doug! What size tire and gear are you running? If your willing to divulge

 

[moobster]

Nice!!! that's a perfect example of tire size and air pressure being correct for the HP of the car.
The rear suspension doesn't even come into play in that launch. As you can see by looking at the top of the rim to wheel well opening, it doesn't change, even when the frontend is in the air. The distance between the 2 stays consistent. The rear suspension may as well be solid, like a dragster.

 

[dvw]

Car has 10.5Wx31 with a 4.30, standard 2.45 1st gear 727. It does rise just a touch when I load it on the brake to 300 rpm (about 3 seconds into the video) due to tha fact it's a foot brake car. With very slight squat at the hit. A word about rear instant center (I/C, front pivot location of the rear suspension location). If the I/C lands ABOVE a line drawn from the rear tire contact patch through the cars center of gravity (C/G), the rear of the body will seperate. If the I/C is BELOW that line the body will squat. Shocks limit the speed at which this happens. A leaf spring or ladder bar has an I/C which are shorter than a 4 link. Therefore the I/C needs to be lower on the line to apply similar leverage. If the I/C is short/high the shocks rebound circuit has its work cut out trying to control seperation. As a few here have found out, you can overload the tire pretty quick. The sidewall will tell you the answer. Don't overload the tire, let it work .
Doug

 

[khryslerkid]

These guys do a great job with videos. See if you recognize anyone.

 

[Mike Gaines]

These guys do a great job with videos. See if you recognize anyone.

Great Videos