Ok, so im trying to improve my 60 foot and need some help. ive been reading alot of the tech articles and just need to check and make sure ive got my thinking straight. my car is lowered and not hooking up right. ive got mickey thompson drag radial 305/35/r18s but the car was lowered with the eibach pro kit. i believe this leveled out my lca angle and pushed my instant center forward and that might be part of the problem. my thought is to buy lca relocation brackets and a chassis mounted torque arm to help me lauch better. what kind of gains can i see from these mods. Is my thinking on track or am i all wrong? let me know, guys and any input is greatly appreciated...i am here to learn lol!

just to add...my best time is 1.98 sixty with 109 trap at 13.02

 

well i was running 2.00 60ft with my nitto55dr's with a stock suspension. when i installed my panhard rod torque arm and my lca's. i was cutting 1.8's all day. so your thinking should be right , it was like night and day after installing all tho's parts

 

I can tell you that in my experience with a stock height car the LCA brackets AND a tunnel mounted torque arm the instant center was too far back. The rear would pop up and blow the tires off. I took the brackets back off and with just a short torque arm it really digs in. If you do try the brackets see what it does in the first set of holes, that may be your best bet on a lowered car.

Vernon

 

You're an M6 I presume? You need a non-radial ET street if you want to pull good 60ft times, though I agree you should be doing better then 1.98.

 

I'm running a body mounted ta standard length with lca and relocation brackets. Best 60 ft time has been 1.68

 

yes the car is a six speed. so it looks like i need to find the happy medium. ill go with the tunnel brace t/a and use the first set of holes on the lca relo. brackets and see how she does. and actually sorry to misinform but the tires are the et street radials II's

 

thanks for the input guys!

 

Any progress so far?

 

I have alway used/heard that the bottom hole is the best to use on a lowered car. I swapped it to middle top before and did not like it and went back to bottom.

 

i got the t/a in and took the car to the track but didnt race it. i thought i didnt have something set right bc there was a lot of banging but apparently that the down fall of heim joints and a tunnel brace mounted t/a. still havent put the lca relocators in yet bc i spent the weekend in detroit for woodward. i will definitely be at the track this Wednesday and will give you updates!!!

 

Someone chime in, dont the lower you go on the relo bracket the farther forward you push the instant center?

 

The lowest hole isnt always the best, it just depends on how low your car sits. You want a slight angle in the lower control arm from the body mount downward to the rearend mount. But dont forget, any time you move the lower control arms up or down, it changes your pinion angle as well.

 

Its where the lines of the LCA's crosss the torque arm front mount. If the LCAS are neutral or pt down then they never cross.

Four Link, Instant Center & AntiSquat

The goal in setting up a suspension is to apply just enough force to the tires to keep them from spinning and let the rest of the force push the car forward.
Draw an imaginary line through the lower control arm forward. Now draw an imaginary line through the upper control arm forward until it intersects the lower line. This intersection is called the Instant Center (IC).
Now imagine the Center of Gravity (CG) of your car concentrated at the shifter handle. Where the IC (Instant Center) is located compared to the CG (Center of Gravity) is what determines how the force of the suspension acts on the car to get it moving. If the IC is too high then there will be too much energy wasted pushing the car skyward. If the IC is too low then there won't be enough force applied to the rear tires and the tires will spin. There are also variables if the IC is in front of the CG or behind the CG. Somewhere there is going to be a position (or more than one) that will apply just enough force to the tires to keep them from spinning and the rest of the force will push the car forward.

While the car is sitting still, the tires have 100% traction. During the launch you don't want to change this. Properly adjusting the IC will maintain the existing traction during the initial launch or Tire Shock. The IC starts working during the first .001 second of the launch and continues for the next 30 feet or so. However, after the first .001 seconds the shocks are playing a very important roll in "maintaining" the traction and allowing the IC to apply the desired force to the tires. For the most part, the IC is what is adjusted to get the initial hook and the shocks should be adjusted to maintain the traction throughout the 60'.

The four control arms on a four link type suspension, when adjusted correctly for a particular car, can help launch a car quicker and use less horsepower doing it. Compared to a ladder bar suspension a 4 link suspension has the added benifit of changing the length of the Instant Center to accomodate more or less front end lift without adding any more Anti Squat.

 

Well with the eibach springs that were on the car when i bought it, the lca's were actually angled up, i put them in the lowest hole bc the if i used the first set they were barely parallel, n now they are just slightly pointed down. ill double check my pinion angle tomorrow n im running at the track on saturday. i guess well see how it all turns out. im hoping to atleast drop a couple tenths off my 60 foot.

 

Well guys heres the update. just got back from the track and the results are in! lol i dropped about two tenths off my 60ft and my 1/4 mile time. i consistently pulled 1.82 60ft times and ran a 12.82 1/4 as compared to my usual 2.02 60ft's with a 1/4 mile previous best of 13.02. so the lca relocation brackets and torque really helped.

 

Nice improvement

 

Indeed, the problem is probably assoicated with the lower control arm angle. Glad to hear this fixed your issue. It's not something a lot or people think about when they lower their cars. There is also a good chance the rearend may be out of position because of the solid factory panhard bar. You may want to look into an adjustable panhard bar to dial that in too if you notice the rearend sitting too far to the left.

- Kevin