some questions

[fishman]

I have a few questions hopefully you can help me out on.

First question is my car has the coil overs in front of the rear end so the chassy guy told me i had to go to stiffer springs......if i remember right i think they are #200 but if i push down on the car it is stiff...........when the car hooks up good the car does squat with the wheels in the air......so if they are to stiff does it create a boomerang affect instead of absorbing the shock it it transmits it causing a problem some were else..........help me out with this and put me on the right trail.

Second question is i was at a diffrent track they i usually go to and my 60 foots were all over the place from run to run..............my local track i usually run 1.38-1.40 60 foots.......this weekend i was running 1.40-1.48 60 foot and it is hard to tell lots of time if i spin but i know when i hook as the front end comes up and most of the weekend it didn't...........this is what i tried to straighten this problem out.......dropped air pressure a few times from 8.5 psi to 7 psi with no luck and dropped my launch from 5200 rpm to 4800 rpm...........my front shocks a single qa1 a loose as they can get set at 0 and the back is set around 7 clicks............so if i would have tighten up the front shocks would this helped out and also if i would have soften the back would it helped out..i know that to stiff creates problems and to soft shocks create problems, the front shocks i think i understand these problems better then the back ones, frame seperation how do u determine as high tire shock how do u tell......i kinda have some answers but not totally sure. thanks for your patiences

car wieght is 2630 with me in it and front 55 % back 45 %
back shocks are also qa1 single adjustment
tires are 32x14x15
car has 600 hp

here is a video
http://www.youtube.com/watch?v=MlNsixubZxs

[fishman]

hummmmmmmmmmm not one reply.........i found some reading material on this so i have cleared some of it up but still need to figure out what the car does if it is to soft i know when it is to stiff it hops..

[CoMax Racing]

I'm from Edmonton and I'm just wondering who you are reffering to when you say "chassis guy". If you don't object to telling me I'd be curious to find out who you talked to.

No big deal if you don't want to say, gotta ask anyways.


Corey

[John_Heard]

Watched your vid. Hard to tell but it doesn't appear to have much front end travel. Might try slowing the front shocks extension down some and see if that helps.

[want-a-be]

How much does this car weigh? 200 pound springs sounds like a ton. Mounted in front of the rear end or not. I have to ask why the springs are mounted in that position? Sounds like you don't have enough suspension movement in the rear.

Don

[fishman]

I bought the car this way, i have no idea why the shocks are in front of the rear end i was just told that u have to have alot heavier springs because of that......what would you recommend like #150 springs in the back. I try to push down on the car and it is very stiff.

I will not say who my chassy guy is as he has treated me good i just am looking for another opinion is all.

Everything that i have read has been about the shocks behind the rear end so the shocks be in front i cannot find any information on if u should have heavier springs and if so how much.



Thanks

[vegaracer]

To be able to tell how much heavier the springs have to be in front of the axle, you would need to know how long you're ladder bar/ lower fourlink bar is from the front pivot point to the axle centerline, and how far the shock is mounted from the axle centerline, both where it is now and where it would be behind the axle. And yes, a front mounted spring does need to be heavier.
Hope all of this made some sense.

EDIT: I confused myself reading this

[want-a-be]

If the springs were in the back I think I would recomend about 100#-125# springs. Even though the springs are in the front of the axle,...I'd still go with no more then 125s. No more then that though imo. Cirlce track guys run their shocks in front and back of the axle. I'm thinking they don't add any spring pressure because of the location of the spring.

Don

[fishman]

car does squat on take off but on i can feel on launch if it hooks or not if it doesn't hook, the wheels do not pull in the air if it hooks the wheels are in the air.............if u push on the back of the car the car does not go down i think it might two of us pushing on the back of the car to get it to go down..........i know that something is not right in the tuning of the shocks, air pressure, rpm launch of spring weight........as i cannot get my 60 foots consistant so it makes it hard for a dial in, usually i have to put a slower number on and if it hooks fender race or do some braking and if it doen't hook run it out the back door.............when i launch i think that it spins every launch a little but some way worse put in the car it is hard to tell and only way when it is bad the front end end doesn't come in the air........when u lose .08 in your 60 foot from one race to another pretty hard to dial any car in and also i hate the time........ i like single digit numbers better then two number.................thanks guys any input is appreciated as the more question asked maybe get closer to resoloving this issue

[fourtenposi]

I watch that video, and the best that I can tell is you are hitting the tire to hard. I wish I had the video so that I could watch it in slow mod, but to me, It is smashing the tire down and it is rebounding and unload the tire and spinning just a tad. I think you need to be able to control the hit better. I would tighten down the rebound on the rear shocks so your not crushing the tire. Once you do that, I think you will find it will work better if you tighten down the rebound/extendsion in the front shocks. It looks like it rises to fast to me. Does it tend to spin worse when the air is better?

I can tell you this, with my car, I race at a couple different tracks. Some as much as a 1000 foot difference in altitude. At the track with the higher elevation, I have to run the rear and front shocks looser, because of the altitude, power is down, and it doesn't hit the tire hard enough. Now if I take that same set up and run it at my home track, it does what your car is doing, hits too hard and unloads the rear wheels. If I just adjust the rear shocks, the front end will come up to fast and hurt the weight transfer. Idea is you want to prolong the weight transfer as long as you can. I have found I have to make shock adjustments though at the year, in the summer in the heat, I have to have the softer settings, and in the cooler months, I need the stiffer settings.

[fishman]

I watch that video, and the best that I can tell is you are hitting the tire to hard. I wish I had the video so that I could watch it in slow mod, but to me, It is smashing the tire down and it is rebounding and unload the tire and spinning just a tad. I think you need to be able to control the hit better. I would tighten down the rebound on the rear shocks so your not crushing the tire. Once you do that, I think you will find it will work better if you tighten down the rebound/extendsion in the front shocks. It looks like it rises to fast to me. Does it tend to spin worse when the air is better?

I can tell you this, with my car, I race at a couple different tracks. Some as much as a 1000 foot difference in altitude. At the track with the higher elevation, I have to run the rear and front shocks looser, because of the altitude, power is down, and it doesn't hit the tire hard enough. Now if I take that same set up and run it at my home track, it does what your car is doing, hits too hard and unloads the rear wheels. If I just adjust the rear shocks, the front end will come up to fast and hurt the weight transfer. Idea is you want to prolong the weight transfer as long as you can. I have found I have to make shock adjustments though at the year, in the summer in the heat, I have to have the softer settings, and in the cooler months, I need the stiffer settings.

Thanks for the input, i will try stiffing up the rear shocks and the rears some this coming weekend. I will also have to double check the spring weight as i know when u push down on the rear of the car it is like a rock.
My car seems to have a problem more with poorly prepped track more then the better air.....i have raced at 4 diffrent tracks this year and 2 of the 4 tracks i had more problems at and these two tracks are cheap with the VHT

[fishman]

I went to the track this weekend and i tightened up the front shocks 2 clicks and the same at the back and dropped my launch 400 rpm...my 60 foots were still all over the place.......i tried dropping form 8 pounds air in the back all the way to 7 psi and still same results...........by the way i checked the rear springs and they are #150 not #200 not sure why the #200 thing was in my head...........but they do seem stiff to me when i push down on the back of the car it is hard to move and only moves very little.................thanks..........funny thing even with the car all over the place i made it to the finals on saturday and the 1/4's on sunday

[fourtenposi]

Hey Fishman,

Did you try to launch at the same launch rpm as before? Have you tried to launch at the lower rpm before? If not, you may have gone to far on the adjustment. Tightening up the shocks reduces the hit on the rear tires, and lower the launch rpm does the same.

How heavy is your car? Could the rear suspension be in a bind or something if it feels so stiff?

Any more video?

[fishman]

Hey Fishman,

Did you try to launch at the same launch rpm as before? Have you tried to launch at the lower rpm before? If not, you may have gone to far on the adjustment. Tightening up the shocks reduces the hit on the rear tires, and lower the launch rpm does the same.

How heavy is your car? Could the rear suspension be in a bind or something if it feels so stiff?

Any more video?

I tried launching higher and lower rpm and sometimes it hooks great and other times not so great..........i try to do everything exactly the same every run to have the same result but on the weekend i had one pass it went 1.38 sixty foot but mosy of them were 1.41 or 1.42 with one was 1.47.......i was wondering if the rear springs are to stiff and absorbing instead of the shocks ...........i have the ladder bars in the middle hole to soften the hit up....i guess i am going to have to tighten up the front shocks even more i am not going to go any tighter in the back as they are at 10 clicks now.........i have tried from 6 clicks up until the tires started bouncing and that was at 12 clicks.........i had a guy told me that wheelie bars would probably help my car run more consistent.............i have no more video i wish i did but i usually go to the track by myself

[fishman]

Update

last week raced in bad air anyways stiffened up the front shocks 3 clicks and the back from 6 clicks to 9 clicks...tire pressure 8 psi, launch chip down to 4800 rpm from 5200 rpm, shift at 6700 rpm and put in C14 from C12 and bumped up timing from 39 to 41 degrees......the car hooked great with the best 60 foots at my local track ever.........1.37 60 foots from the week before running 1.40 60 foots........got home checked the plugs to see if i had to much timing in it, the plugs have no detonation signs and the ground strap discoloration is in the middle so i am going to try going up 1 more degree with timing and then on sunday i am going to try my friends 1050 dominator hopefully it will pick the top end up.....air was bad around 4700 da and humdity was 36 % my weather station said i would run a 10.17 and the car ran 10.12 all day