Critique my cars launch
#1
Critique my cars launch
Im looking to improve my 60’. After taking a slo mo I’ve got more wheel spin off the line than I thought. In this video the tire pressure was low, 7.5psi. I brought it up to 10psi but I’m still in the best 60’ times of 1.48. When I had the tires at 12-15psi it didn’t seem like I could break out of the 1.5 range.
The car has stock style suspension rear with torque arm. Nothing is adjustable except pinion angle, new stock style shocks.
The front is stock suspension running competition engineering shocks setup in 90/10 dampening ratio.
Running a power glide with brake currently set at 4500 on the two step.
What are some suggestions you guys think I should try next time out. Which will be at LS fest where I’m hoping they will have better prep too.
The car has stock style suspension rear with torque arm. Nothing is adjustable except pinion angle, new stock style shocks.
The front is stock suspension running competition engineering shocks setup in 90/10 dampening ratio.
Running a power glide with brake currently set at 4500 on the two step.
What are some suggestions you guys think I should try next time out. Which will be at LS fest where I’m hoping they will have better prep too.
#4
Without climbing under the car and checking I don’t know the pinion angle off hand. Here’s another video including a burnout.
Just so I’m understanding and learning how do the adjustable shocks help in the rear?
Just so I’m understanding and learning how do the adjustable shocks help in the rear?
#7
10 Second Club
Looked like the rear tires are bouncing or tires wading up.
Tires at 7.5-10 was the same 60'...……..and 12-15 to 1.5's...…….guessing somewhere in between there could be the magic number.
4500 off the brake/2-step...……..maybe play with launch rpm ? .........500 less to start ?
Have you looked into a wider wheel or taller tire ?
And yes, DA shocks will help too.
Tires at 7.5-10 was the same 60'...……..and 12-15 to 1.5's...…….guessing somewhere in between there could be the magic number.
4500 off the brake/2-step...……..maybe play with launch rpm ? .........500 less to start ?
Have you looked into a wider wheel or taller tire ?
And yes, DA shocks will help too.
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#8
TECH Addict
iTrader: (57)
Doug G brings up some excellent points. Obviously, with that low of a pressure you are running a bias slick. Is it a soft or stiff wall? 10psi would be the minimum IMHO on a slick. Radials like 17-18 in my experience.
Tell us more. What tranny, gears, tires, etc.
#9
The car does have a competition engineering anti roll bar. It’s hard to see once I download to YouTube but going frame by frame zoomed in the tires appear to travel at the same rate. And it picks the front wheels equally.
I agree 7.5 was def too low of pressure. In that video they were wadding up and “snapping”. My friends got more videos later in the night but the lighting was messing with the slow mo. I’m going to try to get one of those and post it tomorrow. So far 10-12 psi seems to be my magic number, best of 1.481 60’, the 7.5psi run was a 1.531 60’. Not to say as I change things another pressure won’t be better.
My my two step was originally set much lower. Raising it helped but I haven’t played with it much at all.
The cars body pretty much limits me to a 24”x8” slick. My street tires are closer to 26” but you can’t fit a finger in between the front and rear of the tire to the body. I don’t want a slick expanding and contacting causing a blowout on the top end. As much as I know a larger tire will help I want to save this for last so I don’t have to chop fenders. They are already lip rolled to prevent contacting.
The slicks hold the weight of the car without wrinkling under normal sitting and driving. I was shocked to see them wrap up like that. I’m not sure if theyre a soft or stiff wall slick.
The first video was on brand new gas charged shocks. The second videos the shocks were new’ish but cheap and completely blown. They had no gas charge left.
Lastly the trans is a freak show performance built power glide 1.76 first gear. Rear end is a moser built 9” with 3.00 gear and spool.
Thanks for for the help guys, I’d like to see what the car is capable of pulling a low 1.4 or even a high 1.3 60’
I agree 7.5 was def too low of pressure. In that video they were wadding up and “snapping”. My friends got more videos later in the night but the lighting was messing with the slow mo. I’m going to try to get one of those and post it tomorrow. So far 10-12 psi seems to be my magic number, best of 1.481 60’, the 7.5psi run was a 1.531 60’. Not to say as I change things another pressure won’t be better.
My my two step was originally set much lower. Raising it helped but I haven’t played with it much at all.
The cars body pretty much limits me to a 24”x8” slick. My street tires are closer to 26” but you can’t fit a finger in between the front and rear of the tire to the body. I don’t want a slick expanding and contacting causing a blowout on the top end. As much as I know a larger tire will help I want to save this for last so I don’t have to chop fenders. They are already lip rolled to prevent contacting.
The slicks hold the weight of the car without wrinkling under normal sitting and driving. I was shocked to see them wrap up like that. I’m not sure if theyre a soft or stiff wall slick.
The first video was on brand new gas charged shocks. The second videos the shocks were new’ish but cheap and completely blown. They had no gas charge left.
Lastly the trans is a freak show performance built power glide 1.76 first gear. Rear end is a moser built 9” with 3.00 gear and spool.
Thanks for for the help guys, I’d like to see what the car is capable of pulling a low 1.4 or even a high 1.3 60’
#10
Here are the other videos my friend took. The first one from the passenger side is my fastest pass to date and my fastest 60’ to date, 10.41-1.481 both of these passes are with the tires at 10psi
This is a drivers side view with a 10.48-1.489
This is a drivers side view with a 10.48-1.489
Last edited by Romulus22; 08-27-2018 at 12:26 PM.
#14
I was pretty adamant I wasn’t going to buy good shocks anytime soon. Hopefully next year I planned on chopping a lot of the car up and I was going to a trailing arm setup with coilovers. The fronts were pretty cheap and I didn’t think the rears were that bad and spinning that bad. But I’m looking to give myself the best chance I can for this years LS fest East.
Thanks again guys guys I’ll report back with some new videos/times after the new shocks.
Thanks again guys guys I’ll report back with some new videos/times after the new shocks.
#15
11 Second Club
iTrader: (9)
I was pretty adamant I wasn’t going to buy good shocks anytime soon. Hopefully next year I planned on chopping a lot of the car up and I was going to a trailing arm setup with coilovers. The fronts were pretty cheap and I didn’t think the rears were that bad and spinning that bad. But I’m looking to give myself the best chance I can for this years LS fest East.
Thanks again guys guys I’ll report back with some new videos/times after the new shocks.
Thanks again guys guys I’ll report back with some new videos/times after the new shocks.
Same with my car but starting with 315/35/17 nto5R's. Going to 28/11.5/16's Hoosier dr2 radials made all the difference. The taller Hoosier took out the violent hit at the start and let the car pull up to the top of the shocks and stay there without the front coming back down forcing the rear wheels to spin after I already hooked and was moving.
I was using stock shocks with over 130,000 miles. Went from a 1.64 60ft with a really violent hard hit jerkin my head into the headrest to a 1.52 60ft with a much smoother launch. Going to more of a slick I put in frame rails, this was the only change going from the 17" 25.5" tire to the 16" 28" tires".
In conclusion I would say tire rim combo first then fine tuning with suspension then gears and shocks last. Unless you feel you need to gear it back to where the smaller diameter put you. That would be pulling the 4:10's for 4:30 or 4:56's for me. That would get my head slamming back into the seat more where I liked it better. lol.
Last edited by handyandy496; 08-28-2018 at 02:02 PM.
#16
Tires first is a no go, I’m out of room in the body. Tuning suspension is almost a no go, I don’t have multiple lower control arm positions. Gears are never going to change, unless it’s for more gear so it’s nicer to drive on the highway. It’s already crossing the line at 6k as it is. I got my shocks in the mail yesterday and will be putting them on today. I’d like to test this Friday but Ive already got other plans.
#17
10 Second Club
6000 scares you ? I shift at 7-7500 ….let her eat man.
I feel you on the "better hiway manners" though.....3500 @ 65 gets old pretty quick anymore.
I feel you on the "better hiway manners" though.....3500 @ 65 gets old pretty quick anymore.
#18
6000 doesn’t scare me. But if I remember right my engine take a nose dive at 6500 and the rev limit is set at 65-6700. I’m shifting around 6500. You can hear me tag the rev limiter on the very first video because I was getting a little out of shape.
#19
10 Second Club
Aaahhhh, OK. I thought you were worried about going 6000+...….understand now.
#20
LS fest was really busy. Only managed to get two runs in. This was my best. I might have to blame a little bit on my burnout though to be honest. Just wanted to get an idea if my suspension looks better?
QA1 shocks set on 8 clicks compression 3 rebound. Tires at 12psi. 2 step at 4K.
QA1 shocks set on 8 clicks compression 3 rebound. Tires at 12psi. 2 step at 4K.