JesasaurusRex

iTrader: (3)

Want to ask the opinions of you fast folk. Wanting to switch over to a th400 (maybe even glide), and yes i know i've been saying this forever , from my T-5 (how its been holding up is beyond me). Car in question is currently running 10.80s @ 135 on motor and some change...yes 135...i can't drive . This was with a really soft leave, i believe the thing 60d 1.69 that pass but I was still playing around with it yada yada. Best 60 to date is 1.63 even tho I feel there was a 1.5r in there but some reason the track didn't light it up (no 60 time on that slip ). Regardless i think with a lil fooling around the car has consistant 1.5s in it as it sits right now with the 5 speed on motor.

Torque arm i'm using right now is the spohn piece that mounts on the cross member and honestly i'm not impressed. It seems like the instant center is still way too forward and the thing would work better if it were shorter...like the bmr or jegs pieces.

Now the big thing is i really still want to throw the bottle at it to see where it goes (after i get the auto) which is why i'm second guessing a shorter design. It's a small tire car , 28x10, probably be a 29x9 on the unit, and it's to the point where it's like maybe the longer design would work well with the bottle and auto w/ a brake and the shorter design would just hit the tires too hard and/or wheel stand all over the place. Or...the long design will still suck. Or maybe the longer design would work better with the 3 speed and the short one would work wonders with a glide. Basically i don't want the IC so far forward where it's just no good and not so far back where i'll have trouble keeping the front end down.

So basically thoughts and opinions

about 3000lbs race weight, small tire, small block on nuts, manual trans, stock suspension car - now

about 3000lbs race weight, small tire, small block on the unit, auto trans, stock suspension car - what i'm looking to have

mw66nova

iTrader: (13)

my experience is that a shorter t/a will help keep the front end down, as to where a longer t/a will have more leverage and lift the front end...at least that is what car_fixer is dealing with right now.

JesasaurusRex

iTrader: (3)

you got it backwards bub

five7kid

iTrader: (14)

A long torque arm puts the axle twisting force closer to the front of the car. The longer lever means the weight resisting the twist will move less. Together with the front of the car being heavier than the rear, a longer torque arm will move the front up less than a shorter arm will move the rear up.

A short torque arm puts more weight reaction as downward force on the axle. There is a limit to that, of course, as no arm puts no downward force on the axle.

The long torque arm isn't a drag racing set-up. The high number of 4-links on drag-only cars should tell you something.

JesasaurusRex

iTrader: (3)

Didn't think about that, very true.

Anybody else?

KWIK84

iTrader: (5)

I am in the beginning stages of building my own TA, based of of the BMR design and several home-made designs that I have seen at my local track. When finished it will be ~32" long. I decided that I needed to change it after looking at some picks of the car launching as it is almost setting down on my 28" slicks. Hopefully if I design this right I should get a little seperation and improve my 60's.

mw66nova

iTrader: (13)

hrmmm...so in the case of rich's car, a short torque arm would make his problems worse (his problem being that he's got no paint left on either of his bumpers, non on the back from banging against it, and non on the front from when the nose came down and folded the gfx under). how then, would he fix this problem? the obvious wheelie bar is out of the question. he's currently running a stock length torque arm (and will likely chime in soon anyhow )

xpndbl3

iTrader: (5)

mw66nova--he needs to tighten up his travel limiters(if he has them?) or to run a different converter to not have such a high STR rating and flash possibly lower/higher to hit the tires less. Add ballast to the nose of the car, etc etc. There are ways of smoothing it out so it won't carry them that extreme besides wheelie bars.

KWIK84 I would imagine a set of drag bags would stiffen the rear and not let the suspension take the hit from the launch. Another option is relocation brackets on the rear. I am running both drag bags and relocation brackets with a jegster torque arm which is short as well, and the car lifts the rear now.

DIGGLER

iTrader: (1)

i agree with everything xpndbl3 said. my suggestion is to get the s&w setup. subframes and torque arm. its working great on my car (so far).

car_fixer

ah very interesting, so using the logic that the shorter arm lifts more, then you use a 1/4 inch ratchet to loose your wheels, right? I am trying to figure this out. so lets say we had a 4 link car that lifted the front too much , what would you do with the i\c?
also i can put enough anti squat in this thing to jack the rear end up in the waterbox, it also will lift the rear going down the track and it starts spinning the tires when it pitches it foward.
and i do have limiters, and i only leave on 45 hp of nitrous lol, i did find out what happens when i use 150 though, i skip the foward part and just go up lol. and add weight..gasp..the car is too heavy now
so at the moment i decline to answer the long/short question, but i will ask another what about ladder bars, they should make cars flip over backwards then, right?

JesasaurusRex

iTrader: (3)

more opinions needed

mw66nova

iTrader: (13)

i was eating a blueberry muffin when i read this and i laughed so hard i thought i was going to choke!!

BT283

iTrader: (3)

http://thunderracing.com/catalog/?ac...id=739&pcid=89
this would be the ideal torque arm for any harecore street car or any drag race car or the Wolfe Racecraft one works well too. But they are right, the longer torque arm keeps the car on the ground more and the shorter one is more likely to lift the wheels. I have seen Car fixers post in the past and have noticed you talking bout leaving on the progressive at 20% and it still going to the back bumper. Most of my buddys leave with 350-400 on 40% and dont have that problem and they run 5.30s and .40s on stock suspension. I agree with xpndbl3, you need to chain the front down or change the converter.

JesasaurusRex

iTrader: (3)

with the rotation of the axle upward it is obviously pushing the torque arm up which is in return pushing the rear end down (i think). I get what you're saying with the longer lever more torque thingy but, now this is just purely drunk talk, i'm guessing the shorter torque arm pushes down on the rear harder because of how much closer it is to being directly above the rear. For example lifting something heavy straight up above your head or lifting the same object out infront of you with your arms extended...ya i'm drunk so this makes sense right now

BT283

iTrader: (3)

http://www.wolferacecraft.com/detail.aspx?ID=221
Read the part about their torque arm

IHI

iTrader: (1)

This is why i think all the guys thinking the LCA relocate brackets are full of it thinking it makes a huge difference...it's all in the tq arm, plain and simple. long arm make the chasis absorb power, where as the short arm puts more into the tire since it moves the instant center and dramatically increases anti squat.

If your going to add more power, keep the long bar. I had to buy a new set of slicks every month to race...they still had a ton of plug left, but the shock the short jegs arm I use just tears the sidewall right out of the tires. I was always going to get rid of this jegster unit and buy a long bar so the chasis took more of the hit, saving me tire cost per month and making the car work better on hot summer time tracks where traction can be less than desirable.

I would recommend keeping the long bar, you can get away with alot more power on a small tire since it's not 100% upto the tire to make it stick as the chasis will be absorbing power.....I've gone 1.46 on my short bar and 1.47 consistantly, but i think that's about it with a small tire and short bar unless you change to like a CCX stator in your convertor, then you can add a bunch more power with a 3 speed and short tire..60' will fall off but you should pick it up on teh big end.

1989GTATransAm

iTrader: (3)

"This is why i think all the guys thinking the LCA relocate brackets are full of it thinking it makes a huge difference..."

Does not using the LCA brackets change the point of instant center? I think the LCA's are part of the total package along with the torque arm.

car_fixer

lower contol arms have nothing to do with instant center, they push the car, all they affect is anti-squat percentage, they could be right on the front of the axle it wouldnt matter about the ic, instant center isnt really correct when talking about torque arms, 4 link cars have an effetive instant center where they would cross if you extended lines outwards, a torque arm has a center of lift, right where it is connected to the car. to change the center of lift, you need to move the attachment point. boy am i gonna get a load of crap for this lol lets play a little game, find a flat bench that has 2 legs, like at a picnic table, get some thing so you know wich end is the front, so you dont get mixed up. now lift the front end of the bench from the very end,with one finger, easy right, ok now move almost halfway under the bench then try it again really hard right, you just experimented with center of lift, the set of legs oppisite where you were lifting (the rear) is representing the rear axle , your finger was the torque arm. it works the same in the car. long ladder bars are usually about 32 inches ( i have seen a few 34 inch bars not many) they also have a center of lift, that is also the pushing point. my torque arm for example is i think 56 inches or so long, most people have their 4 links set where? somewhere in between there, and they also have the advantage if it is installed correctly of moving the lower arm or link bar up or down depending on power, why, to change the amount of leverage the pushing force has to rotate the car( i am positive somebody has herd the terms pitch rotate) so moving the bar down increases it, the lca's in these third gens are way lower than a 4 link, if i could move mione up without doing alot of work, i would, and it would help alot. and to those people that put hiem ends on the front of a torque arm, bad idea, the rear moves in an arc, a solidly mounted t/a binds the suspension, also puts alot of stress on one joint. I can feal the flaming comming lol. by the way that madman piece looks shorter than a stock one, watch out for wheelys running that.....................

sixpackmtrspts

veiw form the side and draw a line showing the angles of your torque arm and you lca's and compare the results to a ladder bar. stock arm and lca mojnts the intersect point is probably gonna be infront of the car if it even intersects at all, by lowering the lca on the axle your gonna get the 2 to intersect at some point, there by moving your instant center. im still studyin this stuff from the chassis tuning book i got. i know there are certain parts and mods that work, but i wanna know WHY they work and what small changes can do to effect the car.

1989GTATransAm

iTrader: (3)

Yep, and here is a link for further study for those interested. The discussion is by some of the top people in the country.

http://www.speedtalk.com/forum/viewtopic.php?t=6691

car_fixer

re read that section in the chassis book, there is also the contact patch (easyist way i could think of to describe it) and that affects anti squat, basically how much the car squats when you leave the starting line, to keep it simple well say 3 things can happen, 1 it shoves the tire way up into the wheelwell, 2 it stays where it was at rest, or 3 it extends out (raising the back of the car) from the factory theses cars have pro squat, this means they arre # 1 in the examples, using lower control arm relocation brackets should create an even lower contol arm , parallel , and this should stay more neutral like #2 or if you take that too far and move the rear of the lower control arm way down, you get a car that will do #3 , for an example watch a tractor trailer at a light, you will see they raise up in the drive wheel area. to properly calculate the anti squat you need to know the cg location and hight on the car the book should tell you how fun that is to find. to simplify this, more use this logic, the torque arm lifts, the lower control arms push.
instant center, by definition, is the theoretical point through which tire motion is transferred into vehicle motion, this point can be found by extending two theoretical lines from each link out colinerly (in a straight line out that way like foward) the point these lines intersect is the instant center. so by technical definition, ladder bars and torque arms do not have an instant center. an instant center so described above is virtual, not phisical, several vw's and audis , m-b's , mopars and a few others have virtual steering axis's so when you look under the car there arent 2 ball joints there are 4 the piviot is actually the center of the rim (if it is the correct one, throwing 22's on there screws that up) so an arm be it ladder bar, torque arm, or if you are really into drag racing a swingarm ( basically two long ladder bars to keep it simple also where the double frame rail chassis came from) that are attached at the foreword and dont piviot at the rear can not have an instant center, its attached not live. this is gonna be long i can see it

JesasaurusRex

iTrader: (3)

very interesting discussion thanks for the link

car fixer, that car books first of all , second , into that discussion about LCA angle and your car. Obviously the only thing effecting that is the LCA relocation brackets and length of the springs. If i remember correctly i took about 2 coils out of the rear to get my m*llet sitting the way I like (obviously effecting suspension geometry). Now even in the bottom hole with the car sitting how it does the LCA angle is only ever so slightly pointed downwards (lower twoards the rear of the car). Now with stock length springs in theyd be pointed downward tons more and i'm thinking my IC would move back some. Thing is i'm no suspension guru and how greatly this effects the IC i have no clue. So...even with the long torque arm you have, i do not know how much angle you have in your LCA's but is it safe to say your IC could still be a lot more rear ward than say mine just because of the LCA angle (honestly asking because i do not know how advertly it effects IC). And there for even if i did get a shorter torque arm your IC could still be more rearward depending on the LCA angle than mine with very little LCA angle?

Paint i don't care about, but stance i just gotta have and i already have a 4x4 and don't need 2 , so i'm just tossing that all out there in short because even with a very short torque arm, depending on the LCA thing my IC might still not be as far rearward as a couple of you with longer arms.

radialtireking

I have a cross member mounted spohn torque arm on my car. My car 60's in the 1.20's on drag radials on any track.
This pic was on a 130+ degree track that many people were having problems getting down.

JesasaurusRex

iTrader: (3)

but ur car traps 155...

radialtireking

Yes, I realize my car traps 155. My point was the long spohn torque arm will work on a properly set up car. I have run that TA on the car with several differant combos both N/A and nitrous ranging from high 11's to high 8's on several differant kinds and sizes of tires. There is alot more to getting the car to hook than just the torque arm. What's the rest of your suspension consist of? I'd hate to see you buy another torque arm if you don't need to.

JesasaurusRex

iTrader: (3)

wolfe race craft ajustable LCA's, wolfe race craft ajustable panhard bar, wolfe race craft anti roll bar, spohn x member mounted torque arm, 50/50 lakewood shocks, v6 springs cut a coil or 2, 90/10 lakewood struts, trick front drag springs

IHI

iTrader: (1)

Honestly you have a great combination there that will take on a ton of power on a small tire. The only thing you could do to really fine tune it without getting crazy is upgrade to adjustiable shocks/struts, other than that you have all the pieces in place for what your looking for, and the best part is the tires ought to last a little while too...by small tire big power combinations go that is

DIGGLER

iTrader: (1)

jes, all that stuff should work great and is very similar to what im running except for the shocks. i run koni spa-1's on mine and they are working great thus far. with the fronts on full stiff i think the car will still get on the bumper with a little more power. i have some comp engineering limiters ready to go on the front which i hope will take care of that problem. im running full length springs out back minus the rubber isolator, and trick springs with 2 coils cut up front.

car_fixer

the lower arm will affect anti squat, the best position for it is in reality slightly lower in the rear, that way on launch it will then be straight, thus not wanting to extend the rear out of the car, or smash it into the car, so the way it is now is probably ok , stock springs where it is (same hole ) would be not so good, as it may unload the tires farther down track. my lower control arms are parallel with the rockers, as it doesnt squat much i dont need to fight squat. does my car hook , yes, is it good no, how will yours do, with an auto, try it and see it sounds like it will be pretty close, and may or may not require minor changes, small things do make a diffrence, like, i also have a huge anti roll bar so both tires have the same weight on them, also took out alot of chassis twist and flex, so now it has nothing to waste power, well except huge wheelys , the car 60 ft's extreamely well for being on the rear wheels (1.28 to 1.3) i guess you could say it hooks on a gravel road, now i just need to real it in a bit. it goes back to try before you buy, except try what you have now. the front struts you have may work , but they are 90 / 10's they tend to pump up on an imperfect track and will raise the front end as you are going down the track. koni spa 1's are designed not to do that, and are adjustable (sometimes you run out of adjustment lol) does anybody know how long the sphon torque arm is, from the center of the rear to the mounting point?

KWIK84

iTrader: (5)

How much would need to be removed from the distance of a stock mounting point torque arm, to make a noticeable difference?? Does anyone on here have any access and knowledge to a dynamic analysis program to be able to compare the changes encountered by changing TA length?

Also, would it be better, with and adjustable TA, to change the pinion angle, or change the effective length?

radialtireking

X2 on what car_fixer said here. I think you should be close with what you have. You need to put the auto in and try it. I feel some minor tuning will get the job done. My LCA's are level or ever so slightly down in the rear as well. The only thing I could see changing would be the shocks.

And I know what your saying about running out of adjustment with the spa 1's car_fixer. I'm right there with ya!

JesasaurusRex

iTrader: (3)

well fellas yall kinda are making me wish i didn't purchase this jegs piece a day ago haha. While more power and an auto might infact much rather like the longer piece, the spohn arm just wasn't getting it done with how the car sits now. And 300 odd bux is tons more affordable for me at this time than what it'll take to swap a decent th400 into this car. That being said, i'll keep you guys posted on any changes and also fill yall in on when i do do the conversion. Thanks a ton for all the help guys, seems like its hard to find round these parts now a days. Learned a lot

...thanks

-Rex

IHI

iTrader: (1)

The jegster unit will be fine, i've been running it for many years and it works good, it just plays hell on your tires since they take the blunt of the load...but that's what bias ply slicks want, they want to get hit hard so they're shocked into working. I'm consistant 1.47 on a 9" tire all day with a near 600hp motor. If you want to take some hit away for a softer leave, have a CCX stator installed in your converter..simple as that.

one things for sure, dont worry about wheelies comparing to the boys with the cool pics, I cant seem to get much higher than the one in the sig, but my car is a tank though too, so maybe that's the problem.