I'm fairly happy where my car is at launching at the track, if prep is good I can cut a 1.40 60 foot otherwise I'm around 1.45 average. The car is rising fast then dropping on launch, has anyone had this experience and do I fix it with front struts or rear shocks? I have Tokico singles up front and Viking doubles in rear. The car is squatting and hits tires extremely hard. Any ideas welcome thanks
Need launch advice
- Thread starter Blackmax
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Any videos to see ?
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If you have facebook you can see it happen in this run https://www.facebook.com/joel.dasilva.18, its a quick up then down. But was not happening last year with the Strange struts only when I swapped over to Tokico's, I wonder if the new ones are looser and need a tighter setting? Here is a vid from last year,https://www.youtube.com/watch?v=fqKsfdgTkaM
Sorry the facebook didnt work the way i thought ,I will try to load later.
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More compression on the rear, more rebound on the rear so it doesn't unweight so easily.
bj
bj
Thanks BJ , I will do that. I currently have the Vikings at 6 compression and 18 rebound the fronts full loose. Funny how we progress from a 1.8 60 to 1.40 and I still want more lol but I really think you hit a wall. I notice once you get traction at a certain rpm launch you increase rpm which seems to change the game again.
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Tighten your fronts. You don't need them full loose and that exacerbates the squat issue. Since the fronts are single you have quell the dive with compression. It would be "rebound" that would allow them to extend. I'd start at 8 compression and 18 on the rebound in the back with full tight up front.
Only adjust the fronts to the point where you can hook, which means you're now at the minimum amount of 'rebound' to extend and still have a reasonable level of compression up front to quell the dive.
If you get bored look at the ones we're running on our GT500 section on the website (AFCO Racing)
Only adjust the fronts to the point where you can hook, which means you're now at the minimum amount of 'rebound' to extend and still have a reasonable level of compression up front to quell the dive.
If you get bored look at the ones we're running on our GT500 section on the website (AFCO Racing)
What's your mods and what RPM do you launch at? I'm having that same problem myself right now.
Thanks again B.J! Never bored to look at GT 500's . My mods , Viking Double adjustable in rear, Tokico singles up front. Springs are 5300L up front and drags in rear, anti roll bar, 10.5W slicks. My power I around 900rwhp and launch at 4,000 using the B.J. clutch slip.
I'm using the 325/50/15 radial and it's a complete hit or miss with the launch. Either hooks and bounces or blows the tires off. Same rear shock/springs as you but I'm going to try the strange struts. I'm using front BMR drags springs now.
B.J. knows a lot about radials. I can say tire pressure, horsepower, track prep all make a difference. But my problem only happened after I installed tokico front struts and what B.J. said makes sense. The Tokico's are smoother as well much more springy on rebound than the Strange ones I had so need to be tightened up. I want to buy a new set of MT 275x28" Pro 60's and get them to work.
You have to look real close but on this video you can see the pop up and down right at launch. This was at Spokane Washington and I never brought a smaller blower pulley so was way down in power due to elevation. I wonder if because I was down over 100 h.p. that I couldnt carry the front that high. I'll be testing next weekend at sea level and with B.J.'s suggestions
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What is this technique?
Its between dumping the clutch and a plain quick release. Make sure you inch up to the line so the drivetrain is loaded btw. I know I am losing a bit of time on launches and shifting but still using original factory tranny and my clutch is the same one for the past 5 years and over 300 passes. Also 30,000 street miles.
Nicely done B.J. Do you use the upper or lower hole on your uppper control arm bracket? You get just the right amount of separartion.
Upper
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Ok I do as well , I must be getting excessive squat from too soft compression and tire pressure
My pressure is track dependent. On 29 x 10.5 stiffwalls I start around 15 and work down.
At 1:30 on this video I race a small red car and you can actually see my rear tires pop off the ground for a milli second
https://vimeo.com/169962480
https://vimeo.com/169962480
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