Launch problems
#2111708
07/17/16 12:44 PM
07/17/16 12:44 PM
|
Joined: Oct 2003
Posts: 4,013 South Park, Pa.
68LAR
OP
master
|
OP
master
Joined: Oct 2003
Posts: 4,013
South Park, Pa.
|
Bin fighting this all year. Only difference from last year is the flywheel. Last year and years before I had been running an aluminum wheel. Found it was warped over the past winter. Installed a steel wheel which is about 20# heavier. Now the car blows the tires off at launch. I've dropped my 2 step all the way down to 3K from 5K. I've dropped tire pressure down from 15 to 12 psi. I've loosened the rear shocks from 9 to 7. I can't get the car to plant or even control the amount of off line spin. I'm pretty confused at this time..
car weight with me in 3926# slicks 29 12.50x15 gears 4.56 Rancho 9 ways out back 90/10 up front Mopar SS springs
Any suggestion?
4 speed street legal. Best time 10.99 @ 124 mph on 93 octane pump gas @ 3926# total weight
|
|
|
Re: Launch problems
[Re: 68LAR]
#2111768
07/17/16 02:03 PM
07/17/16 02:03 PM
|
Joined: Aug 2003
Posts: 43,315 Bend,OR USA
Cab_Burge
I Win
|
I Win
Joined: Aug 2003
Posts: 43,315
Bend,OR USA
|
How old are the tires and how many runs on them?
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
|
|
|
Re: Launch problems
[Re: 68LAR]
#2111794
07/17/16 02:43 PM
07/17/16 02:43 PM
|
Joined: Jan 2005
Posts: 4,243 Charlotte, North Carolina
sgcuda
master
|
master
Joined: Jan 2005
Posts: 4,243
Charlotte, North Carolina
|
Yes. 20 pound increase is significant in a flywheel. Lots of extra inertia. You've already changed your shock settings and air pressure. It might be time for new tires, maybe a little wider, if you have the room. What clutch and trans are you running? Might need a little lighter clutch plate to allow some slip.
[image][/image]
|
|
|
Re: Launch problems
[Re: sgcuda]
#2111833
07/17/16 03:29 PM
07/17/16 03:29 PM
|
Joined: Oct 2003
Posts: 4,013 South Park, Pa.
68LAR
OP
master
|
OP
master
Joined: Oct 2003
Posts: 4,013
South Park, Pa.
|
Kind of figured that adding 20#'s to the flywheel would mess up my set up, but also thought that I could adjust for it with 2 step, shocks and tire pressure. Tires.... They are old, BUT, still have good depth and I treat them with VHT before every race. I can put my finger nail into the tread area and it leaves and indentation. Like I said, last year I had no issues 'til toward the end of the season when the flywheel started going bad. I have ALWAYS run an 11" CFDF clutch. I drive my car on the street. I don't want to get into adjustments and such. Too old to be crawling under the car before a street cruise or race event. I also realize that what I do with my car is different in a lot of ways than most. There are certain things that I can do and won't do. It's one of those "nitch" things that only a few of us fall into. A good friend of mine just suggested lowering the tire pressure down to 10 psi.
4 speed street legal. Best time 10.99 @ 124 mph on 93 octane pump gas @ 3926# total weight
|
|
|
Re: Launch problems
[Re: Monte_Smith]
#2111850
07/17/16 03:52 PM
07/17/16 03:52 PM
|
Joined: Oct 2003
Posts: 4,013 South Park, Pa.
68LAR
OP
master
|
OP
master
Joined: Oct 2003
Posts: 4,013
South Park, Pa.
|
Oh! they are way older than one year. Probably closer to 5 years, but I don't race every weekend. Maybe 4-6 times a year is all.
The slicks are removed after every race and stored. Last year they were working good for me except for the flywheel issue I had.
Last edited by 68LAR; 07/17/16 03:55 PM.
4 speed street legal. Best time 10.99 @ 124 mph on 93 octane pump gas @ 3926# total weight
|
|
|
Re: Launch problems
[Re: 68LAR]
#2111858
07/17/16 04:03 PM
07/17/16 04:03 PM
|
Joined: Jan 2005
Posts: 2,540 Milwaukee WI
TRENDZ
master
|
master
Joined: Jan 2005
Posts: 2,540
Milwaukee WI
|
I remember one season when I was having troubles going any faster than 9.6s. Kept doing things to make more power. MPH would go up, but never a better E.T. I ended up getting new tires. When I took the old ones off, they were so structurally wasted, that the tire wouldn't stand up and keep it's shape when off of the rim. These were 31w tires(stiff sidewall) The new tires with no other changes went 9.20 on the first hit.
"use it 'till it breaks, replace as needed"
|
|
|
Re: Launch problems
[Re: dvw]
#2111895
07/17/16 04:59 PM
07/17/16 04:59 PM
|
Joined: Oct 2003
Posts: 4,013 South Park, Pa.
68LAR
OP
master
|
OP
master
Joined: Oct 2003
Posts: 4,013
South Park, Pa.
|
Remember, I said that I started with the shocks on the highest setting (9). Went lighter thinking that it would hit the tires harder. Usually I run the shocks on the highest setting (9). From what I've read so far, it seems that a new set of slicks maybe the ticket. I'm going to hate pitching these slicks, even though they look good to me. What about,...I also run tubes in the slicks. Maybe dropping the tire pressure way down (for me), to about 9 or 10 psi? Do you all think maybe this might work?
4 speed street legal. Best time 10.99 @ 124 mph on 93 octane pump gas @ 3926# total weight
|
|
|
Re: Launch problems
[Re: 68LAR]
#2111904
07/17/16 05:18 PM
07/17/16 05:18 PM
|
Joined: Jan 2005
Posts: 4,243 Charlotte, North Carolina
sgcuda
master
|
master
Joined: Jan 2005
Posts: 4,243
Charlotte, North Carolina
|
9 or 10 pounds is kind of light for the weight of your car. Be aware of the way the car handles down the track when trying. Maybe try adding 100 pounds ballast to the trunk first. New tires does seem like the ticket, though.
[image][/image]
|
|
|
Re: Launch problems
[Re: 1980volare]
#2112093
07/17/16 10:56 PM
07/17/16 10:56 PM
|
Joined: Oct 2003
Posts: 4,013 South Park, Pa.
68LAR
OP
master
|
OP
master
Joined: Oct 2003
Posts: 4,013
South Park, Pa.
|
'thought soft sidewalls were the way to go with a stick car????
4 speed street legal. Best time 10.99 @ 124 mph on 93 octane pump gas @ 3926# total weight
|
|
|
Re: Launch problems
[Re: 68LAR]
#2112163
07/18/16 12:41 AM
07/18/16 12:41 AM
|
Joined: Mar 2006
Posts: 9,883 MI, usa
dvw
master
|
master
Joined: Mar 2006
Posts: 9,883
MI, usa
|
Remember, I said that I started with the shocks on the highest setting (9). Went lighter thinking that it would hit the tires harder. Usually I run the shocks on the highest setting (9). From what I've read so far, it seems that a new set of slicks maybe the ticket. I'm going to hate pitching these slicks, even though they look good to me. What about,...I also run tubes in the slicks. Maybe dropping the tire pressure way down (for me), to about 9 or 10 psi? Do you all think maybe this might work? Sounds like it's time to step up to a shock with stiffer rebound valving. You were full tight and now you're hitting the tire even harder. A good slow motion close-up at launch will lead you to what is needed. Doug
|
|
|
Re: Launch problems
[Re: Cab_Burge]
#2112180
07/18/16 01:09 AM
07/18/16 01:09 AM
|
Joined: Oct 2003
Posts: 4,013 South Park, Pa.
68LAR
OP
master
|
OP
master
Joined: Oct 2003
Posts: 4,013
South Park, Pa.
|
Cab, My aluminum wheel cannot be resurfaced. It's a Mcleod wheel, and they want way too much to either replace the insert or for me to buy it outright and replace it myself. (I do have that capability). Anyway, from what I've learned, aluminum wheels don't last long in a street/strip application. mine lasted only 2 or 3 years. (can't remember exactly}. If I have to drop the 2 step below 3K, what's the use in having a slick? Last season, my 2 step was set between 48 and 5200. Tire pressure at 15 psi. No bog. Launched hard, but due to the aluminum flywheel issues, the clutch would slip in high gear. Hell, I'm using the same clutch assembly from last year with the steel wheel and it grabs hard. Nothing has changed from last year 'til now except the steel flywheel. This is what's so confusing....
4 speed street legal. Best time 10.99 @ 124 mph on 93 octane pump gas @ 3926# total weight
|
|
|
Re: Launch problems
[Re: 68LAR]
#2112200
07/18/16 01:39 AM
07/18/16 01:39 AM
|
Joined: Oct 2011
Posts: 3,036 bean town ....Ca
WHITEDART
master
|
master
Joined: Oct 2011
Posts: 3,036
bean town ....Ca
|
I think replacing your 5-year-old slicks would be my first step..
In the 8s N/A.with Brett miller W8's 5.07 at 133 at 2700lb
|
|
|
Re: Launch problems
[Re: 68LAR]
#2112254
07/18/16 03:53 AM
07/18/16 03:53 AM
|
Joined: Nov 2004
Posts: 6,890 North Alabama
Monte_Smith
master
|
master
Joined: Nov 2004
Posts: 6,890
North Alabama
|
'thought soft sidewalls were the way to go with a stick car???? Negative, there ghost rider........LOL!!! 3900lb stick car, I would want stiff sidewall tire, tubes, beadlocks and anything else I could do to stiffen em up.......LOL!!! As to your 5 year old slicks. The sidewalls were probably toast about 4 years ago depending on how many licks they had
Last edited by Monte_Smith; 07/18/16 03:56 AM.
|
|
|
Re: Launch problems
[Re: Monte_Smith]
#2112295
07/18/16 09:57 AM
07/18/16 09:57 AM
|
Joined: Jan 2003
Posts: 10,049 MN
JERICOGTX
I Live Here
|
I Live Here
Joined: Jan 2003
Posts: 10,049
MN
|
'thought soft sidewalls were the way to go with a stick car???? Negative, there ghost rider........LOL!!! 3900lb stick car, I would want stiff sidewall tire, tubes, beadlocks and anything else I could do to stiffen em up.......LOL!!! As to your 5 year old slicks. The sidewalls were probably toast about 4 years ago depending on how many licks they had If they are Hoosiers, the sidewalls were too soft when first aired up.
69 GTX
68 Road Runner
|
|
|
|
|