Rear suspension tech/info needed

[johnnyriviera]

Good shocks go a long way. Stick cars and radials are definitely becoming more popular and people are getting them to work as good and sometimes better. The clutch, shocks, and power management are key. I don’t have the desire to spend a season trying to make radials work. I’ll stick with bias ply. Plus radials aren’t forgiving on a mediocre surface.

The thing I found with radials is that they don't recover. Bias slick you get that 1/2 -1 turn out of the hole and then go. In my experience (and other peoples I've talked to) radials like to dead hook, and if they don't, they just keep spinning. Yes the big time drag radial guys make them work, but they often have a shock package that rivals the cost of a lot of peoples engines! And to your point A LOT of time on clutch setup that often needs adjustment throughout race day to keep up with the track. I rarely need to adjust base pressure, and when I do need to compensate for track conditions I usually do it with launch RPM.

That said, I went quite a ways with QA1 double adjustables. Once I dropped into the 9's I went with Menscer shocks and have been very happy.

 

[Ishiftem]

The thing I found with radials is that they don't recover. Bias slick you get that 1/2 -1 turn out of the hole and then go. In my experience (and other peoples I've talked to) radials like to dead hook, and if they don't, they just keep spinning. Yes the big time drag radial guys make them work, but they often have a shock package that rivals the cost of a lot of peoples engines! And to your point A LOT of time on clutch setup that often needs adjustment throughout race day to keep up with the track. I rarely need to adjust base pressure, and when I do need to compensate for track conditions I usually do it with launch RPM.

That said, I went quite a ways with QA1 double adjustables. Once I dropped into the 9's I went with Menscer shocks and have been very happy.

True dead hook or spin. No in between. I make clutch adjustments often. Mine has a sweet spot for rpm. Even if turns the tire harder it will 60 better than lowering the rpm and hooking better. 5400-5800 is its happy place. I have never heard of anyone who wasn’t happy with there Menscer shocks.I have new Afcos I haven’t tried yet and made a change to the lower bar. Hopefully I can put the typical 1.42-1.43 60 behind me and get to the 1.37- 1.38 it belongs at.

 

[Mr. Chev]

I switched to the Hoosier lightweight radial and my car has never hooked better, the old slicks used to bunch up then the car would fall off the tire so to speak and spin, the stiff sidewall of the tadial makes a huge difference on a heavy car, this is my opinion and ymmv.

 

[johnnyriviera]

I switched to the Hoosier lightweight radial and my car has never hooked better, the old slicks used to bunch up then the car would fall off the tire so to speak and spin, the stiff sidewall of the tadial makes a huge difference on a heavy car, this is my opinion and ymmv.

Not trying to change your mind, but I was having problems bunching the slicks too. Running stiffwall slicks now (MT and Hoosier both offer, recommended for heavy and/or stick cars), and the aforementioned shock adjustments fixed that.

 

[Ishiftem]

I switched to the Hoosier lightweight radial and my car has never hooked better, the old slicks used to bunch up then the car would fall off the tire so to speak and spin, the stiff sidewall of the tadial makes a huge difference on a heavy car, this is my opinion and ymmv.

Yours is an automatic now isn’t it? I think I remember reading on the bullet you took the 4 gear out. Auto and radials are great. Stick cars tend to shock the tire hard and break the radial loose.

 

[Steve "wully bully"]

True dead hook or spin. No in between. I make clutch adjustments often. Mine has a sweet spot for rpm. Even if turns the tire harder it will 60 better than lowering the rpm and hooking better. 5400-5800 is its happy place.

Agreed! Radial slicks won't recover like a bias ply. We launch Wully Bully at 5400 normally as well, below that it bogs, above that it spins (unless the track is really tight). The other combo we put together, it would bog below 6600. Planning other changes for next year, as Adam will be taking over driving the sedan.

 

[Mr. Chev]

yes I did go from stick to auto years back the Hoosier lightweight radial is the same co6 compound as the slick, It really made my car consistent and picked up a 10th in the quarter and at 135 the drive was much more stable than with the slicks.

 

[Mr. Chev]

 

[Mr. Chev]

 

[4Eyedturd]

Got the upper arm braces in, anti-squat brackets bolted in and setting up to weld the arm bracket on the rear end. Before I burn this bracket in, does that gap on the outside of the Global West upper arm look normal for them? I’ll get something to fill it in, just wondering if that was a common issue.

 

[4Eyedturd]

Does anyone have anyway of verifying the upper mount height/location? Does this arm look leaned back to much?

 

[pvs409]

gap looks wrong mine fit the rear end..... and factory arm too far back?
I have lots of pictures of adding arms to 2 factory rear ends and one 9"

more later tonight

 

[pvs409]

picture of arm added on my 62 SS Hardtop

 

[Steve "wully bully"]

Does anyone have anyway of verifying the upper mount height/location? Does this arm look leaned back to much?

From the picture it looks too far back. How is the height of the mount compared to the front upper frame mount when the car is on the ground and sitting at proper height?

 

[4Eyedturd]

From the picture it looks too far back. How is the height of the mount compared to the front upper frame mount when the car is on the ground and sitting at proper height?

At ride height, the front upper arm mount hole is 21 1/8” and the rear upper arm mount is 19 1/2” from the ground So the arm is pointing to the top of the hood or windshield. Which isn’t good I believe. I think I realized why it’s that way. When I welded the arm to the rear I didn’t know there was almost 1/2” of shim between the upper arm mount and the frame. So, I bolted the arm into the frame mount, bolted the rear end bracket to the control arm, sat the bracket onto the rear end, made sure the pinion angle and side to side clearance was good and welded to the rear end.

 

[benchseat4speed]

I think you nailed it. You're taking all the right measurements, making both sides equal length or as close-to as possible, I'd say you did fine.

Couldn't be any worse than the first time I cut a stock passenger side mount off, flipped it over, and eyeball welded it on the driver side With a Lincoln buzz box and 7018 rod. Didn't even have a friggin wire feed welder at the time

 

[4Eyedturd]

I’ve got more questions though, haha. It looks like my top mount is further back than Paul’s, while I could try the other holes in the anti squat brackets to see if it makes any difference. I wonder if having the top mount on the rear to close to the bottom mount is not allowing the bars to control the axle, bar link separation maybe the right words. If so I don’t want to weld the 4th arm bracket in the wrong place now again.

After watching a few videos and seeing how my top bar is pointed I wonder if my anti squat is less than 100% and instant center is way out in front of the car. Which would pull the rear up into the car?

 

[4Eyedturd]

After sleeping on it I’m gonna cut the top bracket off and see if I can get it up higher. How much is the question…

 

[Steve "wully bully"]

Yes, the height you currently have is a lot of your problem. Location of the upper rear bracket depends on the rest of the mounts. If you are looking for drag racing performance, everyone I know of has had the best success with the anti squat over 100% so the rear suspension separates and plants the tires. Height of the instant center will be too high unless you drop the lower frame mount like shown above. Where everything goes is best done by plotting everything out. When that is done, then you can predict what the car will do, instead of waiting for it and hoping for the best. That's what we did over 20 years ago with Wully Bully. Found the instant center about the height of the hood, 60' in front of the car. Changed mounts to put the instant center around the middle of the rocker panel, started getting consistent low 1.40's for 60' times. Further refining got into high then mid 1.30's. This of course is within a 3700lb stick shift car on 10.5 slicks running 10.20's consistently. We also plotted out 7-8 others' cars and offered help that produced similar results.

 

[4Eyedturd]

Granted, I don’t know the weight and I’m sure that affects things but after seeing the numbers in that plot they look terrible…about how you started out many years ago maybe. After talking with a buddy he suggested getting the lower arm parallel with the rocker and then playing with the upper arm to get the instant center where I need it.