Lateral-g Forums - 1985 Monte Carlo SS known as Barney

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- - 1985 Monte Carlo SS known as Barney (https://www.lateral-g.net/forums/showthread.php?t=43529)

As always with this car, packaging is TIGHT. It's all in there though, and it all fits. Bernie did an EXCELLENT job designing this setup. I'm impressed.

https://photos.smugmug.com/1985-Mont..._195205-X2.jpg

https://photos.smugmug.com/1985-Mont..._195233-X2.jpg

https://photos.smugmug.com/1985-Mont..._195129-X2.jpg

https://photos.smugmug.com/1985-Mont..._195057-X2.jpg

I hope I don't have to do much work on upper link at track as it's a bit hard to get too, but I shouldn't have too once I find it's happy spot.

https://photos.smugmug.com/1985-Mont..._192558-X2.jpg

https://photos.smugmug.com/1985-Mont..._192510-X2.jpg

https://photos.smugmug.com/1985-Mont..._192401-X2.jpg

Tomorrow morning I need to swap out the rear springs, then it's off for it's first test drive. Wish me luck...

Quote:

Originally Posted by mfain (Post 716949)

Looks great Lance! Have you measured the pinion angle change with travel with the short third link? Where are you racing in January?

Pappy

So the effective length of the stock style uppers was 8", the new upper link ended up 11.25"...so the pinion angle change should be less than it was before.

Looks awesome. Can’t wait for the review. I thought about this while mine was torn apart but I have to stop the steady outflow of cash. Starting to not be fun anymore.

So I did a bunch of flexing while the springs were out this morning. First I have to say, a 4 post drive on lift makes stuff like this SO much easier than a 2 post.

https://photos.smugmug.com/1985-Mont..._091820-X2.jpg

So, springs out, driver side full stuff to bumpstop, pass side full droop.

Here is tire with roll center at lowest point, 6.75"

https://photos.smugmug.com/1985-Mont..._091837-X2.jpg

And here is that same except roll center is at the highest point 11.25"

https://photos.smugmug.com/1985-Mont..._093612-X2.jpg

You can clearly see the difference in how the axle\tire rotate in roll by how the tire ends up in the fender. Pretty cool...

In static form, neither tire ever touches the frame or inner fender. They both come pretty close to the outer fender lip at full stuff though.

https://photos.smugmug.com/1985-Mont..._093625-X2.jpg

In dynamic form, I was able to get the passenger side to rub just a bit, on the outer fender lip I believe. I set the RCH at 9" for my initial test drive, right in the middle of adjustment range.

https://photos.smugmug.com/1985-Mont..._101055-X2.jpg

https://photos.smugmug.com/1985-Mont..._101108-X2.jpg

Upper link frame mount in middle hole, sway bar in middle holes, rebound in shocks in middle of adjustment range, RCH in middle of adjustment range...time for a test drive.

Right away I could feel a huge difference in how the rear end reacted. In hard transitions back and forth at 45 mph the back felt stuck like I've NEVER felt it before. I had a HUGE grin on my face right away. When being a bit more aggressive swerving back and forth I was able to get it to slide the inside front tire just a bit when on the gas...hinting that it's a touch on the tight side like this. Certainly drivable though. I'd race it like this...if I had too.

I did have a wheel hop problem though. It hops hard, from a dead stop, from a roll, even during a hard 1-2 shift. This is discerning and I need to adjust to correct this. First thing will be raising the front upper link up to the top hole. I also want the rear to roll just a bit less so I think I'll put the rear sway bar on stiffest hole and might put 185# springs in place of the 162# springs in it now. The stiffer springs and more rebound in the shocks may help tame the rear axle down as well.

Hopefully not too many changes at once and it'll be enough to let me feel like I can beat on it a bit harder next time out.

I'm also not sure if it's just the extra noise, or if the tailpipe delete option really opened up the exhaust, but it sure feels peppier when on the loud pedal!! Could just be the car forcing itself forward faster instead of just spinning the tires too.

Nice upgrade! Interested to hear how it goes once you get to race it for the first time.

So, I've driven the car around the streets a few times and have made some adjustments from my initial settings.

First off, the way the rear suspension reacts to inputs now is COMPLETELY different than before and in a great way. I'm so excited about it's possibilities now. I have not been able to get the rear to step out in the somewhat aggressive street driving I have attempted so far, not once. Nor have I been able to get the rear to get the front tires to push...so far, it's pretty dang neutral.

I have had some interference issues I'm working through and a wheel hop issue.

I had the inner fender sheet metal on the passenger side rubbing the inside of the RR tire under hard left turns...the sheet metal was sticking out past the frame rail and a few selectively placed blows with a 5# sledge and some fresh black paint seem to have cured that.

First time out, it would wheel hop just about any time I got on the gas hard. I raised the upper link frame side mount to the top hole, went from 162# to 185# rear springs, put rear sway bar on full stiff (was in middle), added 7 clicks of rear rebound to shocks and raised PHB from 9" to 10" and drove again. Wheel hop is MUCH better, now it'll only hop if I try to make it hop...by being real aggressive on the throttle.

My other interference issue is the Pinion\U-joint contacting the body under full compression. Some of this happened during the wheel hop issues, but it'll also bottom out by just hitting a hard bump at cruising speed. I'm running a 3.5" diameter driveshaft (full inch larger than stock) and a 9" which is much larger than the OEM 10 bolt. It was better after putting the bit stiffer springs in, so I think I'll bump up to the 200# springs I have sitting here and maybe I'll shorten the upper link just a bit as well to try to gain a bit more room. Technically I haven't even measured the pinion angle yet, I initially set the upper link length by putting it exactly where the housing sat with the old links still in place. Moving the frame side upper link to top hole probably added a bit of static pinion rise, so this needs to be addressed. I think I'll leave the spring adjusters where they are when I put the 200# springs in as well which will raise the rear ride height another 1/4" or so I believe.

I think the wheel rate is pretty close to what I'll need, I LOVE the way the rear squats under hard acceleration and you can tell it throws the car forward vs blowing the tires off like it used to do. Lateral load feels decent as well...I haven't tried a hard braking turn yet to see what turn in is like. but from what I can tell corner exit is going to be MILES better than it has ever been before. I need to get the interference issues worked out regardless though before I can really start to throw it around. I'm pretty stoked about how it is going so far though...can't wait to race it this Sunday.

Also, I'm pretty sure the engine woke up a bit when I cut the tailpipes off. I'm getting pretty used to the tone and I'm pretty sure it will pass sound at the track...but I'll still try to rework the whole exhaust at some point to get it out from under the back seat. Latest thoughts are a Y pipe into a single 4" muffler\tailpipe on passenger side up and over the axle dumping behind the RR tire.

So, apparently I'm an idiot... I set my upper link length by the position the axle was in with the old 2 upper links still attached in what I thought was the preferred pinion angle, and then I never measured it to verify it was correct until today.

I had the pinion angle about 3 degrees higher than it should have been. Taking a 1/4" out of the upper link put the pinion angle just under parallel with the trans output and BOOM, just like that my wheel hop and U-Joint interference problems went away. Car is butter smooth at 80-100 MPH and can be driven in full anger with no strange and scary noises. Let's go racing boys!!!

Quote:

Originally Posted by SSLance (Post 717029)

So, apparently I'm an idiot... I set my upper link length by the position the axle was in with the old 2 upper links still attached in what I thought was the preferred pinion angle, and then I never measured it to verify it was correct until today.

I had the pinion angle about 3 degrees higher than it should have been. Taking a 1/4" out of the upper link put the pinion angle just under parallel with the trans output and BOOM, just like that my wheel hop and U-Joint interference problems went away. Car is butter smooth at 80-100 MPH and can be driven in full anger with no strange and scary noises. Let's go racing boys!!!

Is that w/the link in the middle or upper hole? I know you mentioned making changes:

Quote:

I raised the upper link frame side mount to the top hole, went from 162# to 185# rear springs, put rear sway bar on full stiff (was in middle), added 7 clicks of rear rebound to shocks and raised PHB from 9" to 10" and drove again. Wheel hop is MUCH better, now it'll only hop if I try to make it hop...by being real aggressive on the throttle.

Just curious if you switched everything back to the initial points & then all that was required was the slight adjustment on the upper link?

Really glad to hear it's performing well for you, Lance! Good luck at the next race.