trying different suspension combos... ECSB
11-01-2009, 07:25 AM
#51
FWIW, I think cal-tracs are a great product. However I think the IC they provide for EC trucks creates too much anti-squat. They'll hook initially, and then unload. Or they'll lift the rear so much, that it'll never allow weight to transfer. The proper anti-squat value is key, unfortunately its a funtion of wheelbase. Our wheelbase is the longest that I have yet to see anybody with 2wd try to get to hook up. Longer than wagons, and longer than ANY regular cab.
Silver, I think you should start with a cal-trac type setup, coupled with double adjustable shocks front and rear. Then get the lightest front spring possible that will comfortably support the weight of the truck. I think they need to be lighter than what your average nose heavy BB blown drag car uses. The lighter the better, because it will help store more energy. If that doesn't work, fab a torque arm or ladder bar setup to move the IC further foward.
That's what I'm planning to do and I hope it works. Our turbo trucks have all the torque we need, and from what I understand, high torque vehicles like long IC's. Couple that with our long wheelbase, and we probably need an IC that's up near the front of the truck, but at or above the 100% anti-squat line. This is something that neither ladder bars, torque arm or cal-tracs can provide. A 3-link or 4-link could though, but then you're talking major fab work. If we can get the front to rise with cal-tracs then I think we'll be pretty satisfied.
Silver, I think you should start with a cal-trac type setup, coupled with double adjustable shocks front and rear. Then get the lightest front spring possible that will comfortably support the weight of the truck. I think they need to be lighter than what your average nose heavy BB blown drag car uses. The lighter the better, because it will help store more energy. If that doesn't work, fab a torque arm or ladder bar setup to move the IC further foward.
That's what I'm planning to do and I hope it works. Our turbo trucks have all the torque we need, and from what I understand, high torque vehicles like long IC's. Couple that with our long wheelbase, and we probably need an IC that's up near the front of the truck, but at or above the 100% anti-squat line. This is something that neither ladder bars, torque arm or cal-tracs can provide. A 3-link or 4-link could though, but then you're talking major fab work. If we can get the front to rise with cal-tracs then I think we'll be pretty satisfied.
I can tell you exactly where the IC is on our trucks. If you don't have caltracs, then it's the front leaf spring eye. If you have caltracs then the IC is imaginary point where the caltrac bar and the line formed by the front and rear leaf mount meet. Basically the point at which the rear rotates about if the shack/rear leaf section weren't there. Now you can see why the long wheelbase creates huge anti-squat values. Our leafs arent any longer than a RC's yet the truck is a lot longer.
...If the lower bar is level, then your IC is probably infinite or VERY far foward. If the two lines never cross, then there is no IC (infinite) and the rear end will probably squat real hard. If they do meet, but it still very far foward, then I think we're on to something, and thats why you get the 60fts you do.
Do you have any pics? Or can you get a few measurements for me? I'm wondering if cal-tracs should or could be modified to compensate for the added length of our trucks.
...If the lower bar is level, then your IC is probably infinite or VERY far foward. If the two lines never cross, then there is no IC (infinite) and the rear end will probably squat real hard. If they do meet, but it still very far foward, then I think we're on to something, and thats why you get the 60fts you do.
Do you have any pics? Or can you get a few measurements for me? I'm wondering if cal-tracs should or could be modified to compensate for the added length of our trucks.
I have some images at work that I've drawn to scale in ProE of the 143.5" wheelbase and our leafsprings. I don't have access to photobucket at work though, so I'll see if I can just attach them I'm kind of at a loss for where our CG is though. I've been told a car's CG is around 22-24" off the ground or at roughly the camshaft height and near the shifter. My truck has a 2/4 drop, so I put the CG at 28" high and near my shifter. :/
Taken from Dave Morgan' book:
Instant Center- An imaginary point, determined as the center of a radius made by a moving suspension component, that is a point of lift.
This is true for a 4-link/cal-trac setup. But for a ladder bar or leaf spring, it's not a imaginary point at all. Its the front pivot.
As for the lift he talks about...it's easiest to visualize with a ladder bar. Its fixed at the axle in two spots. So as the axle rotates upward from torque, so does ladder bar. In turn, provided the bars are stiff, it will push the chassis upward (lift) at the instant center (front pivot). The same is true for a 4-link/cal-trac, except the point the lift occurs is not a mounting point but an imaginary point, or the point where the two links intersect when viewed from the side.
Where this point lies determines the % anti-squat in relation to the CG height. Also where it occurs in relation to the CG horizontally has an effect too, but I have yet to have any experience or find any concrete proof of the effects.
...
Taken from Dave Morgan' book:
Instant Center- An imaginary point, determined as the center of a radius made by a moving suspension component, that is a point of lift.
This is true for a 4-link/cal-trac setup. But for a ladder bar or leaf spring, it's not a imaginary point at all. Its the front pivot.
As for the lift he talks about...it's easiest to visualize with a ladder bar. Its fixed at the axle in two spots. So as the axle rotates upward from torque, so does ladder bar. In turn, provided the bars are stiff, it will push the chassis upward (lift) at the instant center (front pivot). The same is true for a 4-link/cal-trac, except the point the lift occurs is not a mounting point but an imaginary point, or the point where the two links intersect when viewed from the side.
Where this point lies determines the % anti-squat in relation to the CG height. Also where it occurs in relation to the CG horizontally has an effect too, but I have yet to have any experience or find any concrete proof of the effects.
...
charcoal03silvy, QA1 makes those dual adjustable shocks.
11-01-2009, 10:07 AM
#52
Did some measuring yesterday on the lift... 90 inches in front of the centerline of the rear axle is literally up around the gas/brake pedals.
A ladderbar would have to tie in to the trans X-member baaically. And getting a bar that long to stay rigid under those kinds of forces is gonna be difficult. And that's after you go to a fuel cell and route it around and through a ton of other **** in the way... The bars would have to be build around the carrier bearing support... Among other things.
Looks like a 4 link might end up being the logical way to go for 100% efficiency. I'd still like to keep leafs... Looks like my version of the caltracs will start fabrication this week... Todd, anything I should change about their geometry when building all the tabs/brackets?
A ladderbar would have to tie in to the trans X-member baaically. And getting a bar that long to stay rigid under those kinds of forces is gonna be difficult. And that's after you go to a fuel cell and route it around and through a ton of other **** in the way... The bars would have to be build around the carrier bearing support... Among other things.
Looks like a 4 link might end up being the logical way to go for 100% efficiency. I'd still like to keep leafs... Looks like my version of the caltracs will start fabrication this week... Todd, anything I should change about their geometry when building all the tabs/brackets?
11-01-2009, 10:52 AM
#53
...you know my setup, 2/4 drop, on stock shocks, and only have the passenger side clamped to help out with the chevy lean...dont know what it is but it cuts good 60's for the mods...1.68 60'
if you could get my 60' and if i could get weight of your truck... we both be deep into the 11's!!!lol...
if you could get my 60' and if i could get weight of your truck... we both be deep into the 11's!!!lol...
Wasn't Kyle doin some Kyle-tracs?for all the PM's, I figured it would benefit all of us ECSB guys, and probably everyone in general if I just post my weight reduction mods here. So here goes...
Keep in mind this was my weight with the 5.3/65E/nitrous setup... havent weighed since the turbo kit and 80E swap. I weighed on two different certified scales and both were within 10# of each other, that could be the difference in fuel. I was 3910 without me (225 at the time) when I weighed my truck for my PCS move getting out of the Marine Corps coming back to Texas
also keep in mind my truck is loaded, power everything.... just not leather.
I removed:
front pass seat
rear seat
tailgate
bumper (plastic roll pan)
spare
spare winch
jack & tools
center console
glovebox contents
weighed with about 1/16th tank of fuel
removed nitrous bottle
power mirrors (replaced with manual sport mirrors)
stock 16" Tahoe wheels with 255/55 General UHP's, now I have Tahoe 17's with 275/60 Falkens
I still had the front sway bar and hidden hitch under the truck, which I figure was goo for another 100# give or take. I really dont know why my truck is as light as it is, maybe it was built on a Tuesday?? LOL... I figure with the addition of the turbo kit and 80E I'd be around 4100ish race weight if I removed the same stuff. I plan on taking the sway bar and hitch out of the truck, and adding a rear bumper back. Those may cancel each other out.
Keep in mind this was my weight with the 5.3/65E/nitrous setup... havent weighed since the turbo kit and 80E swap. I weighed on two different certified scales and both were within 10# of each other, that could be the difference in fuel. I was 3910 without me (225 at the time) when I weighed my truck for my PCS move getting out of the Marine Corps coming back to Texas
also keep in mind my truck is loaded, power everything.... just not leather. I removed:
front pass seat
rear seat
tailgate
bumper (plastic roll pan)
spare
spare winch
jack & tools
center console
glovebox contents
weighed with about 1/16th tank of fuel
removed nitrous bottle
power mirrors (replaced with manual sport mirrors)
stock 16" Tahoe wheels with 255/55 General UHP's, now I have Tahoe 17's with 275/60 Falkens
I still had the front sway bar and hidden hitch under the truck, which I figure was goo for another 100# give or take. I really dont know why my truck is as light as it is, maybe it was built on a Tuesday?? LOL... I figure with the addition of the turbo kit and 80E I'd be around 4100ish race weight if I removed the same stuff. I plan on taking the sway bar and hitch out of the truck, and adding a rear bumper back. Those may cancel each other out.
Did some measuring yesterday on the lift... 90 inches in front of the centerline of the rear axle is literally up around the gas/brake pedals.
A ladderbar would have to tie in to the trans X-member basically. And getting a bar that long to stay rigid under those kinds of forces is gonna be difficult. And that's after you go to a fuel cell and route it around and through a ton of other **** in the way. The bars would have to be build around the carrier bearing support. Among other things.
Looks like a 4 link might end up being the logical way to go for 100% efficiency. I'd still like to keep leafs... Looks like my version of the caltracs will start fabrication this week... Todd, anything I should change about their geometry when building all the tabs/brackets?
A ladderbar would have to tie in to the trans X-member basically. And getting a bar that long to stay rigid under those kinds of forces is gonna be difficult. And that's after you go to a fuel cell and route it around and through a ton of other **** in the way. The bars would have to be build around the carrier bearing support. Among other things.
Looks like a 4 link might end up being the logical way to go for 100% efficiency. I'd still like to keep leafs... Looks like my version of the caltracs will start fabrication this week... Todd, anything I should change about their geometry when building all the tabs/brackets?
11-01-2009, 10:53 AM
#54
I have a single ladder bar that it attached to the cross member in front of the rear end. The shock on the right side was relocated.
My truck dead hooks all the time without any wheel hop, The 60' is usually in the high 1.7's/low 1.8's. I need more power or a bigger converter. I think I should be able to get in the 1.6's.
My truck dead hooks all the time without any wheel hop, The 60' is usually in the high 1.7's/low 1.8's. I need more power or a bigger converter. I think I should be able to get in the 1.6's.
11-01-2009, 12:05 PM
#56
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I have a single ladder bar that it attached to the cross member in front of the rear end. The shock on the right side was relocated.
My truck dead hooks all the time without any wheel hop, The 60' is usually in the high 1.7's/low 1.8's. I need more power or a bigger converter. I think I should be able to get in the 1.6's.
My truck dead hooks all the time without any wheel hop, The 60' is usually in the high 1.7's/low 1.8's. I need more power or a bigger converter. I think I should be able to get in the 1.6's.
Originally Posted by silver-mod-o
Did some measuring yesterday on the lift... 90 inches in front of the centerline of the rear axle is literally up around the gas/brake pedals. A ladderbar would have to tie in to the trans X-member baaically. And getting a bar that long to stay rigid under those kinds of forces is gonna be difficult. And that's after you go to a fuel cell and route it around and through a ton of other **** in the way... The bars would have to be build around the carrier bearing support... Among other things.
Mounting the long ladders outside of the frame rails would cool for packaging, but I think you'd rip the mounts off like you did your long bars. Moving them inboard means you have to relocate the gas tank and other stuff. Jason's setup seems to be a good compromise, especially if you ran a coilover suspension. One 43-48" long ladder bar/torque arm, coilovers, two control arms outside the frame rails, panhard/watts link. That would work well.
A 3-link would work well too. I'm going to crawl under the truck today to see if this is feasable. Two lower control arms, one big strong upper control arm thats offset (passenger side). It should behave better than a 4-link, but offer just as much adjustability. If you offset the upper link just right, it will cancel the torque applied through the differential, which would give you equal tire loading at launch.
But if you really want to keep the leafs, you can't beat a simple torque arm setup with a shackle upfront. Any other setup that's worth a crap with leafs is going to require a housing floater, which will screw with your ride height.
Last edited by vanillagorilla; 11-01-2009 at 12:12 PM.
11-02-2009, 10:50 AM
#57
any word on the 3 link setup??
option A: Build 'caltracs' that have the proper angles for our wheelbase, make the front mounting point lower so the bars are parallel to the ground or close, with some adjustability. This one may be tried first simply because I have everything here to do it with.
option B: I like the ladderbar setup outside the frame rails. Not for the cool appearence factor LOL, more for the fact I dont have to move the fuel tank. The mounts wont be an issue once I design them better. My longbar mounts werent really designed to handle the pre-load I had on them anyway
adjustability may be an issue here trying to figure a way for multiple mounting locations for the front of the bars.
option C: The single ladderbar/torque arm setup. Probably easier to package and fab since its half the work. If need be I could attach it to an existing crossmember or fab one dedicated for the bar. This would have to built stronger (in my thinking) since it would have to handle the force that two bars normally would. Half the material, twice the work.
any more insight on these options VG??
option A: Build 'caltracs' that have the proper angles for our wheelbase, make the front mounting point lower so the bars are parallel to the ground or close, with some adjustability. This one may be tried first simply because I have everything here to do it with.
option B: I like the ladderbar setup outside the frame rails. Not for the cool appearence factor LOL, more for the fact I dont have to move the fuel tank. The mounts wont be an issue once I design them better. My longbar mounts werent really designed to handle the pre-load I had on them anyway
adjustability may be an issue here trying to figure a way for multiple mounting locations for the front of the bars. option C: The single ladderbar/torque arm setup. Probably easier to package and fab since its half the work. If need be I could attach it to an existing crossmember or fab one dedicated for the bar. This would have to built stronger (in my thinking) since it would have to handle the force that two bars normally would. Half the material, twice the work.
any more insight on these options VG??
11-02-2009, 11:03 AM
#58
option A is why i went from the shackle hanger drop to the flip kit. with the shackle hanger setup there was no possible way to get the bar parallel to the ground.
with a flip kit the caltrac bar is exactly parallel with the ground on my setup on the bottom hole. i can still set it to the upper hole for a more aggressive launch. i cut a new best 60' with this setup.
im wanting to be the first extended cab 2wd to hit that 1.59 mark. the flip kit helped, hopefully the 28x10.5-15 and bogarts help a little and i also went from my fuddle 3600 to a circle d 3 disk 3600/3800 converter. still need to relocate my shocks.
with a flip kit the caltrac bar is exactly parallel with the ground on my setup on the bottom hole. i can still set it to the upper hole for a more aggressive launch. i cut a new best 60' with this setup.
im wanting to be the first extended cab 2wd to hit that 1.59 mark. the flip kit helped, hopefully the 28x10.5-15 and bogarts help a little and i also went from my fuddle 3600 to a circle d 3 disk 3600/3800 converter. still need to relocate my shocks.
11-02-2009, 11:34 AM
#59
my shock mounts will definitely be relocated in this whole ordeal...
I'm thinking with the front mount that goes around the leaf eye, make it longer with a bigger drop to get the bars down more in the front. Maybe have 3 holes for the front bar mount for more adjustability. I can play with this some, I've got an entire 5x8 sheet of 1/8 steel plate LOL... I'm sure I'll build more than one variation... What would be the best for a roller? The one that rides on top of the leaf.
I'm thinking with the front mount that goes around the leaf eye, make it longer with a bigger drop to get the bars down more in the front. Maybe have 3 holes for the front bar mount for more adjustability. I can play with this some, I've got an entire 5x8 sheet of 1/8 steel plate LOL... I'm sure I'll build more than one variation... What would be the best for a roller? The one that rides on top of the leaf.