Okay, Grumpy! Suspension question

[Grumpy]

When you throw in a coil over and double adjustable shock, then the adjustable links, man can a guy who likes to change things can get into trouble. Especially if he isn't taking notes on what works and what doesn't. This isn't a sat afternoon activity. Could take weeks or months depending on your getting after it. Just one change can throw the whole thing off and if you cant go back to what worked you get to start over. Kinda like when you are bleeding brakes and you let the reservoir go dry.

It takes plenty of persistence.

WINNER WINNER CHICKEN DINNER     

[TexasT]

I'm the guy with the broken parts, trying to be a racer. Hope the sis in law visit is going well.

[Steve Wood]

Yep, Rich!  You got it perfectly   It's not PnP

Two identical cars usually are  not...

[Steve Wood]

Jeremy, that reminded me that I used to have a set of those Lakewood anti-hop bars that raised the rear of the upper bars.  I never installed them because I figured they were an invitation to break the ears off the diff.  I don't know what I did with them...might still be out in the shop some place.


I scanned a bunch of articles and many said, set the lowers parallel to the ground--but none said why LOL


If the center of gravity is somewhere in the range of 54-55% (front end bias) of the wheel base, and the IC is at the front bumper, or further forward, one is not going to get chassis separation.  That's the reason I have always been interested in pulling the IC back.  I guess if one does not make enuf power to blow the tires away easily, it is not that important but it is one of the things that has always nagged at the back of my mind.


with a 108" wheel base, that puts the cg about 60" behind the front hubs so the IC has to come way back to achieve chassis separation.  I may have a different opinion in the morning LOL

[TexasT]

What do you plan for tires? Could make a difference. I think the lower arm parallel to the ground doesn't let that arm get leverage like it does when at an angle. This is why the bushings are a big deal and can be made better with the stiffer material in the bushings so the arm stays and doesn't move all over the place. I think this is why you see those cars with wheel hop that could be remedied with some new bushings.

[Steve Wood]

tire height does make a difference as does spring height.  This is more a theoretical discussion arising from someone wanting to borrow my set of drops and I thought drops were probably not what he needed.  Instead I voted for lowering the front of the rears.


Without looking at the car and taking measurements, it is flying blind and I don't like doing that.


On my cars:


I have run 275's/60's for years.  But, last year, I went back to a 26" set of street tires on my GN as the front tires were 20 years old LOL


that car has lowering springs all the way around and sits two inches lower than the other car that has the 28" DRs on it.


The lower car has the Lower control arms almost parallel to the ground with the front end just a hair higher than the back.


The car that is about 2" taller, has the back of the lower arms quite a bit lower than the front end which means it has the IC pulled back quite a bit in comparison to the lower sitting car.


I need to get some fresh gas in the challenger and get it off the rack.  Then I can take some measurements that are accurate because my lift is adjusted level and my floor is not so level.

[TexasT]

With the stock stuff, I think the "cowboy rake" works well. If you look back at Lawrence Conley and his "black" in the early days he had a real tall front tire and the thing leaned back with some real wide tires on he back hanging out if the wheel wells.

[daveismissing]

Interesting discussion. Does anyone know what kind of a 60ft one can achieve with just a GNX suspension?

[TexasT]

Depends on the tire. That gatorback was a slippery unit in the eighties. One of the locals here had a gnx when new and had it into the twelves in short order but he had some sticky tires.

[Steve Wood]

seems like street cars go for the bars parallel to the ground to minimize roll steer and to minimize binding...


It's been a while since I saw a GNX launch but I seem to recall they lifted the rear end a bit on launch.

[wmsonta]

It's been a while since I saw a GNX launch

1:54
Gn.....0:28
https://www.youtube.com/watch?v=x0p1805OgmE&feature=related
Pure stock, 60' was only about 0.1 sec difference. GNX was over 1 full sec quicker to 60 mph.

[Grumpy]

I'm the guy with the broken parts, trying to be a racer.

ya wanna play an just go a little quicker.. Oh wait. I can do this. A little quicker again.. then ya have a little sensation on your bottom lip. It's a fish hook .. Your doomed  Parts break. Or maybe a weak link. One other thing.. From the 1.3s and faster poly bushings don't cut it. Russ was changing them every other race. Make sure you check the car over good before ya go racing. Great thread. 

[Steve Wood]

yep...that's the road to hell!

[Steve Wood]

Dan, did Russ go Del-a-lum bushings? Or is there something newer/better?

I see that keeping the lower arm near parallel to the pavement helps reduce wheel hop along with good bushings as mentioned by Rich and Dan'

[nocooler]

I’d imagine it’s rod ended....