08 smackdown updating

[Krooser]

Thanks Jet... I forgot about that thread.

[collateralDamage]

What's an LXT?

Basically, LXT has bolt-in 4 link plates for the bottom bars. Cars will have a T at the end of the serial number.

[Matt49]

Smackdown cars use 17.5" upper 4-bars and 15.5" lower 4-bars.
Gen-X cars use 18.25" upper 4-bars and 16" lower 4-bars.
The LXT has two rows of holes for the uppers so you can run either configuration but it didn't make sense to put two rows of holes c2c 1/2" apart on the bottom for obvious reason. Hence the blot in plates are needed so that you can run either setup.
LXT has Gen-X frond end and most everything else about it is Gen-X design. The right frame rail is higher in the rear than a regular Gen-X which requires a difference in ride height of 3/4" to get your static geometry correct.

[Krooser]

Thanks Matt... I'm thinking of updating the four bar mounts on my 1894 MB wide combo... I mean 1994! The bottom brackets only have two holes (was a leaf car)... the top has about five but are single shear. I ordered some brackets form A&A and will do a mock-up and see how they will work.

Hope I didn't hijack this thread to much... as usual you guys have been lots of help...

[tin man]

Also. The LXT right side frame rail is raised an inch higher than the H cars. There is one less lower link hole on an LXT vs an H car

[TheJet-09]

CDNRocket18R: The crossmember is simply raised up. I cut mine horizontally just above the tube that the R&P plate is welded to, then literally cut and fit it to sit inside/on top of the down tubes (where the lower control arms bolt to). With the R&P now higher, you need to go to slotted ends on the R&P, or you'll probably never get bump steer even close. The supports for the crossmember that run back towards the motorplate will also need to be cut/realigned/welded. For the right hand support tube, I just cut/welded it from underneath the right hand motormount.

Another difference between the Smackdown and Gen-X is the lower control arms on a Smackdown bolt behind the crossmember whereas they bolt in front of the crossmember on a Gen-X (which puts it further back, helping to keep it out of the ground even more).

I believe a few years back someone (I forget who) posted pics of an updated crossmember they put on a Smackdown (I'm fairly certain), and it resembled that of a Rocket. I remember thinking it looked like some high quality work. If I can find the thread, I'll post the link.

[MasterSbilt_Racer]

CDNRocket18R: The crossmember is simply raised up. I cut mine horizontally just above the tube that the R&P plate is welded to, then literally cut and fit it to sit inside/on top of the down tubes (where the lower control arms bolt to). With the R&P now higher, you need to go to slotted ends on the R&P, or you'll probably never get bump steer even close. The supports for the crossmember that run back towards the motorplate will also need to be cut/realigned/welded. For the right hand support tube, I just cut/welded it from underneath the right hand motormount.

Another difference between the Smackdown and Gen-X is the lower control arms on a Smackdown bolt behind the crossmember whereas they bolt in front of the crossmember on a Gen-X (which puts it further back, helping to keep it out of the ground even more).

I believe a few years back someone (I forget who) posted pics of an updated crossmember they put on a Smackdown (I'm fairly certain), and it resembled that of a Rocket. I remember thinking it looked like some high quality work. If I can find the thread, I'll post the link.

Jet,

I am pretty sure the rack mounting holes are up and back. The Gen X style cars have more angle in the tie rods when looking down on them from above. This gives the car more "Ackerman" and is part of the reason they turn so well.

[TheJet-09]

^^^ Agreed, I have noticed the amount of Ackerman on the Gen-X as compared to the Smackdown. Almost looks like something isn't right when looking down on it. I believe the Gen-X also calls for only 3/8" of toe out while the Smackdown was more like 3/4".

So when they raise the crossmember, they also move the rack plate back? Or maybe I misunderstood. I just raised mine up in the same location front to back.

[Krooser]

I noticed on my car that the steering arms do not run parrallel to the lower control arms... parrallel and equal length with the lowers was what we strived for when we searched for zero bumpster with a Ford stub 30 years ago... a shorter steering arm on my MB spindles would fix that plus give my old 3.4 rack a little quicker ratio, too.

Comments?

[MasterSbilt_Racer]

I noticed on my car that the steering arms do not run parrallel to the lower control arms... parrallel and equal length with the lowers was what we strived for when we searched for zero bumpster with a Ford stub 30 years ago... a shorter steering arm would fix that plus give my old 3.4 rack a little quicker ratio, too.

Comments?

That's old thinking.

[Krooser]

Well I AM old... so that would explain some of it.

[let-r-eat]

What's the new thinking? Geometry change over the years?

[Krooser]

The "old way" with a rear steer setup was to have the steering arms angle inward at the back of the spindle...when drawing a straight line from the ball joint thru the tie rod end the lines from each side would intersect at the differential... That was good. If you had straight steering arms the line would run parallel to infinity and that was bad.

You could never get zero bumpsteer with rear steering arms because the lca's and the tie rods we're operated on different planes and we're different lengths. I ran Impala steering arms on a '65 Ford stub and fabd my own centerline to correct bump steer...but that took all the Ackerman away.

[CDNRocket18R]

Ok another question. If I decide to keep this car and updates the cross member I’m thinking about running a stacked RF.any suggestions where to start for springs

[fastford]

most call it a 2 stage , which is what it is , on rt front , if you will search this section , you will find some great info already posted......