Redoing My Rear Suspension, Need some advice

Det_Riot

Det_Riot

Forum Member
I've recently decided to take my car's suspension set up from a street car that I take to the track to a track car that I drive on the street. It isn't a daily driver but I drive it most weekends in the summer. Its a '94 Mustang.

My current set up is strange 10-ways, TeamZ rear springs, hpm megabyte Jr lowers and single adjustable uppers. After watching videos if my car at the track, you can clearly see the ass end lift on launch and zero weight transfer. (I'll post videos when I get home)

I took all my 4 link measurements a few weeks ago and at my current height and set up my car has an anti-squat value of 183% and my instant center location is 26" in front of my rear axle. Clearly less than ideal.

While messing around with numbers, I found that by doing the upper control arm mounting point on the axle side by 2.5", it would give me an AS value of 100% and instant center of 47". I know there is no golden rule where to set it but it's a good place to start.

Due to these findings I decided I was going to make a relocation bracket similar to the teamZ/baseline but one that would lower my mounting point. The more I thought about it, the easier it seems to just put some brackets on my axle tubes right by the carrier and run a parallel upper control arm configuration.

If I were to run the upper arms in parallel, how would I keep the car stable on the street? Would a panhard bar work in a drag racing configuration or would that hurt my launch even more?

I guess I'm looking for any kind of insight or advice to get my rear set up correctly for the track. Any help is greatly appreciated!
 
I'm not sure I would try to reinvent the wheel. Team Z series upper relocation kit seems to work really well. I plan on running this same set up on my street mustang.
 
Jdubb said:
I'm not sure I would try to reinvent the wheel. Team Z series upper relocation kit seems to work really well. I plan on running this same set up on my street mustang.
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Looking at the pictures of them installed, they move the location of the upper control arm up. To achieve correct geometry, I need it to move down. Putting theirs on and raising the mounting point up would give me even worse 4 link values
 
Jdubb said:
I'm not sure I would try to reinvent the wheel. Team Z series upper relocation kit seems to work really well. I plan on running this same set up on my street mustang.
Click to expand...

Yes they do! 1.54 60 On BFG Drag Radials.

I can't see how you could move the rear of the uppers down so low (2.5" from stock as you say) and still have them intersect forward of the rear axle. Maybe I'm missing something.
 
So here's what I'm working with:
10970078235_4450a30c3f_b.jpg


This is my current control arm configuration overlaid onto a picture of my car. At it's current configuration, the upper control arms mounting points are located at 16.19" off the ground on the axle and 13.13" on the frame side. This points them down at a significant angle.
The lowers have the axle side mounting point 6.75" off the ground, and frame side of 7.63"; pointing them up at the already greatly sloped upper control arm lines

As the picture above shows with that diamond, that is the approximate location of my instant center... 22" infront of my rear axle, aka horrendous. and my anti squat value, of 171%

Now, moving right along. The following pictures is how my control arms will be arranged by dropping the mounting points and moving them forward.
10970078295_fc4e004fdb_b.jpg


As you can see, the intersection of the two control arms will move forward. By putting these numbers back into the 4 link calculator and not touching the lower the control arms, it will drop my AS value to 99% and move the instant center out to 44". From that point, I'll have a pretty solid place to start with fine tuning the car at the strip, which would be different shock and strut settings on the front and the rear.
 
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Do you already have the Jr's in the top hole at the axle? Also, don't those place the mount point lower than stock at the rear even on the top hole?
 
TooSlo86 said:
Do you already have the Jr's in the top hole at the axle? Also, don't those place the mount point lower than stock at the rear even on the top hole?
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They're at the bottom hole currently. The upper hole will help some. The other thing I'm trying to keep is the same ride height. Since I'm not about to cut new springs, leaving the lowers in place will retain the same ride height. If it ends up that I should just scrap this idea about moving the uppers down that far, I'll likely end up going rear coilovers to control ride height but I'd rather not have to take that plunge yet.

Sent from my XT1080 using Tapatalk
 
You'll have to pick one or the other. Lowered stance or a car that works at the strip. Unless you can figure out Carlos Sobrino's secret from Dave Z. When my car went from street to strip it gained altitude. Like JDubb said, why re-invent the wheel, I believe it would have been addressed in the aftermarket world were there a demand for such. You have to sit back and think why you are trying to do the EXACT opposite of what the tried-and-trued Team Z relocated uppers accomplish.
 
TooSlo86 said:
You'll have to pick one or the other. Lowered stance or a car that works at the strip. Unless you can figure out Carlos Sobrino's secret from Dave Z. When my car went from street to strip it gained altitude. Like JDubb said, why re-invent the wheel, I believe it would have been addressed in the aftermarket world were there a demand for such. You have to sit back and think why you are trying to do the EXACT opposite of what the tried-and-trued Team Z relocated uppers accomplish.
Click to expand...

Quoted for truth. THere has to be an issue with your measurements or math. You are the only person who i have seen needing to do the adjustments you are. also, you can do a lowered ride height and make the car work, you just first need to know how low you want to go. if going low enough you maintain the upper location and geometry and start moving the lower around. Dave (Team Z) also makes a set up to lower the mounting point of the lower at teh axle point. HIs company has multiple stock mounting point/spring location cars running 1.1X 60' times with no real coil overs, or modified pick up points besides his relocated uppers. As others have said, dont reinvent the wheel. (respectively speaking)
 
For what its worth, my car had the Mega Byte lowers on it and to make it work without pushing up the rear at launch i lowered the car alot to get the geometry right. I had no issues running 1.40 60' on a junk motor. I had the car low enough to make the lower arm almost level with the ground with it bolted to the lower hole.
 
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