I couldn't find exactly what I was searching for... I was reading that in order to install sub frame connectors you have to have the suspension loaded, well I dont have a drive on lift. How can I fully load the suspension to install these at home? Im learning how to weld soon so I was thinking save a few dollars and install myself . All I have is ramps and jack stands. Please help!!!

 

You want the body to be relaxed when installing the sfc. Not the best solution, but you could jack up the car and place the front axle stands under the control arms, as far out toward the ball joint as possible, and at the rear, place the jackstands under the axle. The other possibility is to lift up the car and place a length of 6" X 6" wood block under each tire. Both of these methods are not as good as a drive on lift, do that if you can.

Or you can drive up on the ramps at the front, and use the axle stands at the rear.

 

Most important thing is that the chassis is STRAIGHT... doesn't matter if the suspension is "loaded" or not. Remember, if it's not STRAIGHT (like if one corner sags compared to the others, or the ground it's on isn't flat and level, etc.) you will be locking it into a tweeeeek FOREVER.

 

drive the front wheels up on the ramps.

then place a jack under the center of the rear axle, and jack it up. Place your two jack stands under the axle, as close to the control arms as possible.

 

Thanks for all the replies! I'm going to see if I have some 6x6s laying around. But if I do the jackstand method or driving it on ramps and jack standing the rear should I take a level and level off the car to be as straight as possible?

 

Anything that doesn't have it falling off the stands is level enough.

 

Not trying to hijack this post but is using a frame style lift suitable for installing sfc?
Can't find anybody local who has a drive on

 

By falling off the stands you mean really unlevel right?

 

Pretty much

 

I for one would like to know the importance of it being level. I have held on to another set of SFC's that I want to get WELDED in (my Alston's are bolted) and then bolt my Alston's back in. But I can't find anywhere local that has a drive on and a good welder.

The only places I have to do it aren't level at all; although I could definitely put it on 4 jackstands and do it. Would this be acceptable? Would love to get my double SFC setup finished and in!

 

I am so glad I do not have to trust the advice on forums for learning info. Almost every one of these answer is wrong+ Sofa is correct but more needs to be added. I have talked about his so many times on here as to why a loaded chassis would be wrong. 1) uneven floor, 2) preloaded swaybar, 3) uneven tire pressure, 4) uneven spring rates.......should I continue ?

The car needs to be placed on jack stands under or as close to the "suspension mount points on the chassis" as close as possible. Those jackstand points need to be leveled side to side (meaning that both fronts level with eachother, and both rears level with eachother. it the chassis is then lifted slightly off one of those points then sand bags etc (weights) need to be added tot he chassis inside the floorboard above those points accordingly to get all 4 of those points solid onto the leveled jackstands-

You then weld away. Good luck.

This should be noted as the ONLY way to properly weld in SFC's

Dean

 

How do I set up those jack stands? Simple. Jack the car up and place it on the stands with the two fronts just behind the rear A-arm bushings area, then the rear stands just inside the rear LCA chassis bolts area. measure the aprox height of each front stand and each rear stand-save these two measurements, you will need to reference the in step 4 below.

Step 2- mark the ground around the jack stands with tape so you can replace the stands in this exact position. Let the car down then mark the tire positions on the floor so you can get the car in hopefully the exact same spot or at least very very close to it. we are trying to re-hit the same concrete spots under the jacks next time you position the car.

step 3- take the car back down and move it out of the way

step 4- reposition the jack stands in each numbered locations accordingly. Do no mix them up. set them each in pairs in the appropriate position at the appropriate work height recorded in step 1.

step 5- now level each front across from eachother with thin sheet metal plate shims under each stand until borth fronts in their working heght position range are level- and then do the same for the rears leveling them side to side with eachother (a long straight edge,etc with a level on it, or a laser level etc. many ways to do this but they need to be precise side to side) Record these heights and shims so you can place this exact setup back under the car in the marked box positions.

step 6- reposition the car in the garage in the recorded tire spots of step 2, jack up and reposition the raised car onto the recorded level height positions of al 4 jack stands.

Step 7- inspect the jack stands. Any gaps between the chassis and the stand on any one of the 4 jacks? no? the continueto weld away.... if yes there are gaps? then plance weights on the chassis somehow (be creative) to weight the chassis to sit flat on all 4 stands. This may take some substantial weight of the chassis is not square in height. sand bags weight 50 lbs each apox and several of them on the gap raised stand area plus its diagonal opposite stand area work very well to bring the diagonal teeter totter of the chassis to flat and level- then weld away.

Good luck and happy welding

 

I have also come to the conclusion over the years that double SFC's is a good thing. I prefer the outer perimeter rocker rail style SFC's for sole use (increment welded along the span like Spohn demonstrates on his website of course), but the addition of the inner (Alston style) also will "also" add weight to the chassis in the best location possible along with the outers= low and in between the axles. Added weight here is exceptional for a 3rd gen to help reduce the heavy upper roll weight of the chassis. Helps in stiffness (always a plus). Increases sprung weight (better ride quality). The only bad is that any time you add weight anywhere if slows the vehicle and puts more load weight on the tire contact patches for cornering. more positives then negatives, just add a little HP and/or subtract weight elsewhere like fiberglass hood etc that is reduced weight up high above the roll axis.

 

Im looking at the BMR Subframe Connectors on hawks. Are these any good? What should I get inner or outer? Or whats the best/easiest SFC to install? (Im new to SFC so help me out!) Im going to do everything but weld these in (Cleaning, And setting them in where they need to good, ECT.) I have a family friend thats been welding in a ship yard for YEARS so ill get him to weld them in place. EDIT - I was looking at the jegsters bolt on SFC also. (I will have them welded after bolted on also.)

 

I choose Spohn SFC's at the time I did mine becasue of the fitment and the ability to weld them along the span in 1" increments every 4-6" inside* and outside* (Floorboard* and rockerrail*). I would buy these again right now if doing another car. It is my first hand opinion on install and actually vehicle rigidity. I recommend just buying BARE metal units because you would have to grind ALOT of poweder coating off them to install them properly (silly that he sells them with coating)- then just wirebrush and spray them with epoxy aplliance paint to protect them with a hard durable finish.

Look at the pictures on his website so you understand the importance of these being increment welded to shear panel the floorboard in strength so they become one with the car- they are not just welded in front and rear points.
http://www.spohn.net/shop/1982-1992-...-Top-Cars.html

 

Hi Dean,

I noticed that there are inner and outer SFC's to choose from. Some get one, some get both. Since you do autox do you have just the spohns?

Thanks
Chuck

 

Think he mentioned he has both, prob does with him racing but a street car does not need both. Overkill............

 

Same here; except I haven't the vaguest clue whose product is on my car. I think they date back to before Steve started making em. Guy at the race car shop borrowed my car for something and as payment put them on it. Did a DAMN FINE job of it too; bolted the car to his jig, welded as described above, very clean neat thorough and orderly job in every way.

 

Your lucky, guys like that are few and far between...........

 

I do not have that car anymore, and I only autoX'ed the 3rd gen a few times just for kicks to see what it would do against a few other locals in a grudge match. I used to autoX in my 68 Vette from 1987-1993 so I did have alot of autox experience and 68 class wins in those almost 7 years. My 3rd gen was built as a daily driver /grocery getter for the now ex wife.(just to give a little dated history- I never raced the 3rd in snactioned SCCA events- it was only the occational screwing around in it after making modifications in order to tweak settings and see improvements as I developed it for bulletproof daily use and safety.

yes I just had the outer perimeter style Spohn SFC's. they are all you need. I only listed having both becasue the low and centered axle weight addition of the Mac or Alstons would only aid in good ride quality with added chassis rigidity (I mean they can't hurt- of course more bracing will make anything stronger) and where that weight is added is best you can get for chasis dynamics of weight transfers. I talked abot this more in depth in a post that was locked about grip and chassis weighting tricks.

There are alot of myths about SFC's that people do not understand structure and chasiss twist. They do not understand ladderbar construction, they do not understand triangulation modification of ladderbar construction, and they do not understand shear wall or shear paneling and how it resists lateral load and also vetrical twist of the chassis.

The Mac and Alstons do not do this. Tey are merely drag racing style SFC's to simply lift the front of the vehicle under torque to transfer nose weight up to load the rear of the car. You will still see massive chassis twist from nose to tail when these are on a big HP drag car that is launching with the wheels off the ground.

 

But the spohns dont triangulate, they are just a long beam along the pinch weld with a bar in the middle that's welded on pretty much perpendicular. The main benefit of the spohns is that they can be welded to the pinch and the floor, something no other outside SFC offers (except mine that I built myself) Adding the 'spohns does not a ladder bar make, and for structural rigidity in twist and torsion, a ladder bar is pretty **** poor. You need "height" to add any meaningful twisting rigidity, which means a cage. Triangularion in a flat plane does not do anywhere near what it does when you add height to your structure. Panelling over a triangular structure does make it a lot more rigid but where are you doing that when welding spohns to the underside of the car? The whole paneling only applies when you have it rivited or skip welded all across the whole triangular structure like a tub.'


IMO the spohns are too hyped up. Have several cars here
1 w/ only spohns
1 w/ only unis
1 w/ alston/macs
1 w/ umi + alstons
1 w/ home made triangulated welded to outside + chassis brace under car
1 w/ home made """ + mac

Of the cars with the single set of SFCs the one with the home made ones is by far the most torsional stiff. All these cars are set up with koni yellows, reds or bilsteins.

Here's a sheeted triangulated structure that does work:

 

Red shows 2 dimentional structure with triangulation

Black shows basic laderbar construction. This linked construction helps longitudinal SFC beams from twisting along their span.

Green is increment sticth welds to shear panel the 2 dimentional structure.

Yellow show lateral structire front and rear via vetrical firewall and rear seat shear panels- front has my added lower boxed brace (3 dimentional structure). the center is the trans mount bracket which is lateral struture at the center of the two black ladderbar construtions.

 

Alot of you are missing the vertical structure of the inner trans tunnel as a horizonal and vertical structure that has effect on ladderbar construction when you use outer perimeter sytle SFC's. There is no outer vertical structure due to the door void so the addition of stronger longitudinal material here (outer style SFC's increment welded to the rockers) help in the ladderbar construction of each side of the chassis and aid in the vertical longitudinal bracing against chssis twist through this mid section of the car.

By only using Alstons here. there is not aid in the vertical points of the firewall and the rear seat shear panels. THIS IS WHY THE ROOF CRACKS ON THESE CARS

Red is longitudinal "vertical" panels

yellow is lateral "vertical" panels

You can see where the addition of each type of green SFC's will or will not effect vertical lateral shear panels fore and aft. The outer SFC's tie into therse points with more leverage and the ladder bar construction of each individual side help in resisting chassis twist betweent he front half of the car and the rear half.

If you were king kong and grab each bumper of the center picture below and twisted (the pic with only the Alstons) you can clearly see the weakness in the center of the car to resists twisting the chassis and cracking the roof. The last picture obviously shows more strength through this mid section from twisting.