suspension guru's...
10-09-2006, 11:55 AM
#1
suspension guru's... tested my new stup this weekend... ahd was having a hard time getting the car to hook.
car's got a 402, th400, big converter that goes to about 5800 on the transbrake, 4.10's, 27x11.5 hoosier qtp's, spohn 1 inch solid stock style swaybar, bmr adj tq arm, th400 crossmember, with relocation, frame connectors, etc.etc. I was trying to leave off the transbrake with the pedal to the floor, but was having problems with the car not transferring weight right and spinning, then going. Wasn't spinning down track at all, just on the initial hit. I am thinking at this point that the spohn stock style sway bar needs to go away and I need to put a wolfe on it so the suspension can be preloaded correctly, but I dunno. I tried teh tires at 13 psi, then down to 12 psi, ended up with the shocks at 3 on the fronts ( qa1 r series) and 3 on the left rear, 4 on the right rear (std 12 way rears) The car was leaving level and going strait, no problems with the car dog trcaking or anything like that... just wasn't hooking as hard as it should. best 60 foot I got from it was a 1.60, and the car ran 11.06@123.24.... I knwo it's got a ton left in it, with the gearing and conveter the car should be capable of 1/4x 60 foot times no problem, getting the 3620 raceweight into the 10.8x range I'd suspect... just now sure what to do to get the car to hook off the brake better. I didn't try footbraking the car, or leaving at anythign other then off the floor... way I look at it if I want the car to run a mad #, it's got to heave HARD, so I don't really want to do anything to take away power at launch (2 step or anything like that) One thing that I think I can do to help is to remove the rubber top spring mounts, to get the car sitting a little more level, this I think might help it transferr weight a little quicker... I'm gonna try doing this and resetting the pinion angle to the lower ride height before the next time I run the car, hopefully it will help some.
If anyone has any other suggestions, please let me know. Thanks.
car's got a 402, th400, big converter that goes to about 5800 on the transbrake, 4.10's, 27x11.5 hoosier qtp's, spohn 1 inch solid stock style swaybar, bmr adj tq arm, th400 crossmember, with relocation, frame connectors, etc.etc. I was trying to leave off the transbrake with the pedal to the floor, but was having problems with the car not transferring weight right and spinning, then going. Wasn't spinning down track at all, just on the initial hit. I am thinking at this point that the spohn stock style sway bar needs to go away and I need to put a wolfe on it so the suspension can be preloaded correctly, but I dunno. I tried teh tires at 13 psi, then down to 12 psi, ended up with the shocks at 3 on the fronts ( qa1 r series) and 3 on the left rear, 4 on the right rear (std 12 way rears) The car was leaving level and going strait, no problems with the car dog trcaking or anything like that... just wasn't hooking as hard as it should. best 60 foot I got from it was a 1.60, and the car ran 11.06@123.24.... I knwo it's got a ton left in it, with the gearing and conveter the car should be capable of 1/4x 60 foot times no problem, getting the 3620 raceweight into the 10.8x range I'd suspect... just now sure what to do to get the car to hook off the brake better. I didn't try footbraking the car, or leaving at anythign other then off the floor... way I look at it if I want the car to run a mad #, it's got to heave HARD, so I don't really want to do anything to take away power at launch (2 step or anything like that) One thing that I think I can do to help is to remove the rubber top spring mounts, to get the car sitting a little more level, this I think might help it transferr weight a little quicker... I'm gonna try doing this and resetting the pinion angle to the lower ride height before the next time I run the car, hopefully it will help some.
If anyone has any other suggestions, please let me know. Thanks.
10-09-2006, 12:25 PM
#3
See, I'd agree with that if there wasn't guys that are launching stick cars at 6500+ rpm by dumping the clutch and hooking... if you can side step a stick car at over 6000, why can't I launch off the brake at 6000?
Car's got alot of potential, once it starts hooking it's really gonna move out good.. just have to get it to take the initial hit without blowing the tires off.
Car's got alot of potential, once it starts hooking it's really gonna move out good.. just have to get it to take the initial hit without blowing the tires off.
10-09-2006, 03:12 PM
#7
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Maybe I missed it, but I did not see you mention what TorqueArm you had?
I would take a look at your torque arm setting. Hopefully you have an adjustable TorqueArm and set it to -2Degrees. If you are still not hooking you can go a bit more agresive, -2.5Degrees and so on.
I have stock springs front and back, stock shocks out back, with Hals out front. Granted my car is about 3350 with me in it, But even on poor traction days I am in the 1.45 to 1.46 range with a best of 1.40 60' I usualy come out at 6000 to 6500 and slip the clutch very quickly, not dumping it.
I would take a look at your torque arm setting. Hopefully you have an adjustable TorqueArm and set it to -2Degrees. If you are still not hooking you can go a bit more agresive, -2.5Degrees and so on.
I have stock springs front and back, stock shocks out back, with Hals out front. Granted my car is about 3350 with me in it, But even on poor traction days I am in the 1.45 to 1.46 range with a best of 1.40 60' I usualy come out at 6000 to 6500 and slip the clutch very quickly, not dumping it.
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10-09-2006, 05:53 PM
#8
Madman, it's not hooking and unloading, as soon as I let go of the button, it would spin the tires about 4 to 6 times and then hook and go.. it felt like a delay almost.
Car has a BMR cromoly stock style tq arm, mounted on a bmr th400 crossmember with instant center adjustmet. I do believe the pinion angle is at about -1 degree I do believe, I may try adding a degree to it... I'm gonna pull the rubber mounts the stock springs sit on and put a piece of fuel line over the springs to get some of the rake out of the car, it's sitting a little high in the back because the front is lowered about an inch or so. I'll recheck the pinion angle after I pull the spring mounts out, probably end up getting a little more neg. pinion angle from lowering the back an inch or so.
I have a rental I am trying to get things done for this Friday, if I can get to it I will have this stuff done, as well as a little more weight out of the car too, that passenger's seat is gonna come out at a minimum My goal was to get the car to 10.99 or better... it ran 11.0 @ 123 the first full pass with a 1.6 60 foot time, I get the car to 1.4x and its' gonna see 10.8 I'm sure of it... just a matter of getting it out of the hole better.
Car has a BMR cromoly stock style tq arm, mounted on a bmr th400 crossmember with instant center adjustmet. I do believe the pinion angle is at about -1 degree I do believe, I may try adding a degree to it... I'm gonna pull the rubber mounts the stock springs sit on and put a piece of fuel line over the springs to get some of the rake out of the car, it's sitting a little high in the back because the front is lowered about an inch or so. I'll recheck the pinion angle after I pull the spring mounts out, probably end up getting a little more neg. pinion angle from lowering the back an inch or so.
I have a rental I am trying to get things done for this Friday, if I can get to it I will have this stuff done, as well as a little more weight out of the car too, that passenger's seat is gonna come out at a minimum My goal was to get the car to 10.99 or better... it ran 11.0 @ 123 the first full pass with a 1.6 60 foot time, I get the car to 1.4x and its' gonna see 10.8 I'm sure of it... just a matter of getting it out of the hole better.
10-09-2006, 05:54 PM
#9
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Originally Posted by JL ws-6
See, I'd agree with that if there wasn't guys that are launching stick cars at 6500+ rpm by dumping the clutch and hooking... if you can side step a stick car at over 6000, why can't I launch off the brake at 6000?
Car's got alot of potential, once it starts hooking it's really gonna move out good.. just have to get it to take the initial hit without blowing the tires off.
Car's got alot of potential, once it starts hooking it's really gonna move out good.. just have to get it to take the initial hit without blowing the tires off.
who cares if stick guys can dump(most i'm sure are slipping a little) there clutch at whatever rpm, all cars act differently..just because one can work a certain way does'nt mean yours will...
you need to lose the mentallity that in order to run the best time the car can it needs to be launched at kill, off the brake with your foot to the floor
if the car's tracking straight and you think you have the shock settings close, then i would do as madman suggested and try leaving off a 2 step at a lower rpm or even for just for a test, come out a little easier off the brake without a 2 step.. see what it does or even foot brake it..and as Bitemark46 suggested, it would be a good thing if you could get the car on video doing what you described...
jay
10-09-2006, 05:58 PM
#10
Teh car got taped when it was run, just a matter of getting him to post it up, I will pt a link to it here once I have it. If I get to the rental this Friday I do plan to try to launch the car a little easier, ring it up to 4500/5000 and see what that gets me.. I'll probably try footbrakign it once too for the hell of it, I'll have the time so I can try stuff like that.. the other day I didn't really have the time to make a ton of runs, I knew I was only gonna get 3, maybe 4 runs in, that being the case I didn't want to change everything every pass.
Once the video is up I'll post it, hopefully it will give a little insight. I was told I didn't have the car lined up perfectly strait, that certainly didn't help any I'm sure but ther is still something to be learned I'm sure.
Once the video is up I'll post it, hopefully it will give a little insight. I was told I didn't have the car lined up perfectly strait, that certainly didn't help any I'm sure but ther is still something to be learned I'm sure.
10-10-2006, 07:19 AM
#15
I think your problem is the 27" tires. Just my opinion.
From what I can tell, we have a similar setup. I have 28" slicks, Spohn sway bar (which works awesome BTW and totally fixed my launching crooked and twisting) I set my shocks up at "0" up front and "8" out back. I launch off the t brake and get consistent low 1.4's. I wouldn't call myself a "Guru" but I have spent ALOT of time dialing in this set up.
I do have an iron block so maybe the "0" setting up front needs to be there for the extra weight transfer but I would bet if you put a set of 28's on there, with a few minor adjustments you'll be hooking.
Also, just because your car is leaving straight spinning doesn't mean it will when you hook.
From what I can tell, we have a similar setup. I have 28" slicks, Spohn sway bar (which works awesome BTW and totally fixed my launching crooked and twisting) I set my shocks up at "0" up front and "8" out back. I launch off the t brake and get consistent low 1.4's. I wouldn't call myself a "Guru" but I have spent ALOT of time dialing in this set up.
I do have an iron block so maybe the "0" setting up front needs to be there for the extra weight transfer but I would bet if you put a set of 28's on there, with a few minor adjustments you'll be hooking.
Also, just because your car is leaving straight spinning doesn't mean it will when you hook.
10-10-2006, 07:58 AM
#17
Originally Posted by JL ws-6
15 x 9.75 bogarts.
Daren
10-10-2006, 08:02 AM
#18
Originally Posted by GIZMO
I'm not an expert on this, but why do you feel that you need such a wide tire? I would think that you would do better with 10" - 10.5" tread width max. on that rim. Right now if you run a lot of tire pressure your contact patch is probably in the middle of the tire only. If you run very little tire pressure (as stated above) your contact patch is probably only on the outside edges of the tire. Just something to think about.
Daren
Daren
10-10-2006, 08:07 AM
#19
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Being a stick guy I drop the hammer between 6500-7000rpms. On video like NRC mentioned I noticed I do spin a tad on the initial hit. I'm still cutting mid 1.5's but I'm going to lower my launch rpm to maybe 6-6500. You can only launch as hard as the track will allow.
But having stock springs upfront doesn't help either. If you are going to stick to a strut/spring setup get some drag springs. That will help. Down the road a k-member will definately help weight transfer especially if you go to coilovers. When I switched from the stock K to the tubular and coilovers I noticed it doesnt come up as fast as a strut/spring but once up, it carries longer. -Mark
But having stock springs upfront doesn't help either. If you are going to stick to a strut/spring setup get some drag springs. That will help. Down the road a k-member will definately help weight transfer especially if you go to coilovers. When I switched from the stock K to the tubular and coilovers I noticed it doesnt come up as fast as a strut/spring but once up, it carries longer. -Mark
10-10-2006, 08:48 AM
#20
Once the front is up it seems to carry for a while, I went with the R series front shocks to help with that. I'm not opposed to changing the springs, only reason I didn't right off the bat was because my shop's had stock springs in a couple cars that they've gotten into the 8's... I figured that they would be o.k. that being the case.
As for the tire size, I put the biggest thign I could find that would fit without having to hack the car in any way.. but at this point Im open to a little hammering/trimming of the bumper cover, the car's got so much left in it it seems foolish not to just do the modding to clear the bigger tire.. they'll be going on come spring time I am 100% on that.
I will post the video as soon as I have it, hopefully it will give some more insight.
As for the tire size, I put the biggest thign I could find that would fit without having to hack the car in any way.. but at this point Im open to a little hammering/trimming of the bumper cover, the car's got so much left in it it seems foolish not to just do the modding to clear the bigger tire.. they'll be going on come spring time I am 100% on that.
I will post the video as soon as I have it, hopefully it will give some more insight.
