Ok, got sub frame connectors great which type do you have and are you happy?

Just a few threads on this. I like the Alston SFCs.

Welcome to the forum!

Yea the alstons will fit convertibles. Most others need extensive modification to install. Go with the alstons first then if you are hard core go with a cage.

88 IROC CONVERT,

I've been researching subframe connectors for several months. The only players in the vert SFC business that I can find are Spohn and TDS. Both companies are sponsors of TGO. Some people report using MAC and other brands but I don't know if they still make them.

I really like the way the Spohn SFC's are designed to run along the ASC installed brace and the floorboard. They really tuck up high and out of the way. But I ran into problems with the rivets that hold the ASC brace to the floorboard. It would take someone with some fabrication skills to work around the rivets. I ended up sending mine back to Spohn.

That leaves TDS. As you can see on the link that Cadillac posted. The TDS SFC's attach to the lower control arm and drop down and run forward to attach to the front subframe. Some people report minor ground clearance issues with lowered cars.

The other advantage of the TDS SFC's is that you can bolt them in. This means that you can work out any installation issues at home then drive your car to your welder. Hopefully this will save on installation cost and give you more control of the install.

Here is a link to the post I made when I was having problems with my Spohn SFC's

https://www.thirdgen.org/forums/conv...-vert-sfc.html

And finally, thanks to the guy who posted pictures of his installed TDS/Chris Alton SFC's.

I lied. I've got one more thing to say. I'm still waiting for pictures of Spohn SFC's installed on a vert. I'd like to see the newer tubular one's if possible.

The only correction I have to make it that the manufacturer of the Alston SFC's I sell is Alston Racing in Illinois, not Chris Alston's Chassisworks of Sacramento, CA.

Lon Salgren
Top-Down Solutions

I apologize for the incorrect info.

But still edifying...

Thanks. I've become too lazy to write stuff that long anyway.

Ok, I was looking for opinions of the people who have them installed. So it seems that the alston install well, the spohn are stiffer but are a tough install on convertible because of the asc riviots. What about the mac? who makes them, where do you get them and what is the story?

I JUST put MACs on mine a couple days ago and love how much stiffer the car is but it still seems like it flexes some. Although they look exactly like the alston ones.

Tha MAC SFC's install to the same mounting points as the Alston, so they have a similar bend pattern to them. However how they attach is very different. The MAC SFC's have a plate that gets welded to each mount point. The Alstons have a formed shet metal cup that surrounds each mounting location to form a tight fit before they are either bolted to the car or welded or both. Compare the pictures, they are not the same.


MAC SFC's


Alston SFC's

Lon Salgren
Top-Down Solutions

I installed the Spohns on my '89 a few years back, and they went in without any difficulty..bolted and welded right up.

Spohn-style... stays out of the way.

here is some pics of spohn subframe connectors on a vert

i need to buy me a set of those things sometime soon...i gotta pay off the balance on my student account at school first though. $400 for books

Thanks for the pics 90-irocdx3.

I'm still trying to figure out why the rivets that hold the ASC brace on my
car hang down about 3/8 of an inch. Maybe the long rivets were part of the squeak reduction program of '91-'92 that I keep hearing about. The spohns sure look good.

The 'verts weren't made by GM, they were made by ASC so anything changing in the manufacturing process would've stopped before they even cut the roof off.

Hey Plntx, my 88 got the rivets too

You guys who have the spohns on a vert, your installer didn't happen to trim the rivets, did they?

Hey BlueZee28,
You like to take pictures. You need SFC's. Post a pic of the area where the SFC goes on your car.

you want me to take a picture of the underneath of my car?

sorry, i didn't understand that? lol

Yeah, what does the area right next to the ASC brace look like on your car?
(Got rivets hanging down? How far?)

i'll try and go get a pic today. i've got classes right now

I had spohns SFC installed in my 88 Vert (it's the older conversion - with the 87 top release setup) and I had the rivets concern.

My installer wound up fabbing up metal shims to "bridge the gaps".

Of course that was done last November and I've only driven it 20 miles since then so it's tough to tell how they work.

Thanks,

George

These pics exist in this thread:
Aborted Spohn install

last time I was Was under my my trans am I looked over the subframes, And they are stamped with GM and a number, but I do not have number off the top of my head.

I HAVE THE ALSTON SFC'S ON MY 90 VERT, AND THEY FIT GREAT, EXCEPT THE CANT NOW RUBS ON THE SFC!!!! THEY DID MAKE A BIG DIF OVER JUST THE ASC STOCK SFC.

WHEN THE WEATHER GETS BETTER, I AM GOING TO INSTALL THE ONES FROM SPHON. I WANT TO MAKE SURE MY VERT FLEXES AS LITTLE AS POSSIBLE. JUST MY 2 CENTS.

I put the Spohn tubular SFC's on my '89 RS convert with no problem at all. No cutting, fabrication, mods, etc. Fit nice and tight up against the frame and at all attachment points.

Does your car have the rivets? If so, how did the SFC fit in relation to the rivets?

Pics???

I moved my cat just a little on one of my cars. I used SSM SFC's on my T-top car, what I did not like about hem is they were bare metal, I had to powdercoat them myself . not a biggie just thought they should be done from the get-go.

How you move the cat is you heat up the exhaust with a torch and then bend it... worked out well.

John

Hawk's sells the MACs , they're relatively inexpensive.

Where on the subframe is the number?

John

heres my spohn SFCs...... lol. just got them today.


my plan is very simple.... hold the SFC in place, and mark it.

using a grinder, im going to remove the undercoating near and around the SFC....

any rivets that are in the way will be ground off.. then the material it was riviting will be welded together... then ground flat... sounds like alot of work, but honestly, it'll add less then a half hour total to the install time.


once i have it fitting up there firmly, and everything is shiny new bare metal, i'll weld it in 2" strips alternating between the floorboard and the ASC bracing...


hopefully, the end result will be a nice SFC install.

MrDude_1,

Could you take some pictures while you are doing the installation?
I am interested in how the removal of the rivets goes.

Grinding the rivets is obviously the way to go to get them out of
the way. But, will you be able to secure the ASC brace with a weld.

Don't forget that there is a brace in the rear seat floorboard area.
It is located on top of the floorpan.

Keep us updated!

i have no idea if i can or not, but i guess im going to find out.... lol

i'll try to have someone take pics as i go, but i doubt i'll be taking off the helmet and stopping to take pics as i go along.. so i guess it depends on if anyone else helps..

I put on both the Spohn's and the Alstons this spring - HUGE difference, and I haven't even replaced my tired springs and shocks yet. Car rides/handles much better, and 75% of my squeaks and rattles are gone. Oh yeah, I also put in the Edelbrock strut tower brace at the same time.

noone has mentioned kenne brown. these guys were the only people i could find that made sfc for 3rd gens when i was looking. they fit well and as i remember they were priced reasonably.

Kenny Brown isnt making them anymore last I heard. Its too bad too. I had them on my 95 Z28 Vert and they were amazing!

Don't forget a wonderbar, too! Big difference.

wow thats pretty sad ASC riveted the "subframe connector" on there as opposed to welding it on. how cheap

riviting it costs more then the tac-welds that hold your car together.... well thats not fair.. its not just tac welds....


alot of your car is glued together too... lol



theres nothing wrong or "cheap" about them using the type of rivits they used...

yeah the rivets are far inferior to a tig weld

I think you loose sight of the process involved in production welding. Although it would be less expensive and stronger to weld the subframe connectors to the car, you must also realize that to do so would cost more money.

To Rivet the SFC's to the car:
1) raise up the car,
2) align the SFC's
3) drill holes,
4) rivet them into place
5) lower car
Done!

To weld the SFC's into place
1) Remove door threshold
2) Remove forward kick panel
3) remove rear trim pieces
4) remove seats
5) remove carpet
6) remove any residual carpet material backing
7) get fire extinguisher
8) raies up car
9) align SFC
10) weld SFC into place
11) lower car
12) install carpet
13) install seats
14) install trim
Done!

Makes a whole lot more sence for producion purposes

John

they couldve at least welded one side. i just cant imagine going under a new convertible today and seeing a structural component riveted on there

Do not lose sight that the convertibles were not made at the factory, If they truely a car that was made wholely at the factory then they would have been welded on. Since the cars were converted After they were basically a complete car, welding is not a good idea, especially when you add in the fire hazard from the Paint, Carpet, Plastic pieces etc... its just not feasable in a post-production, production setting. If they welded the pieces on then they would have had to re-paint the cars in those areas to boot... it just does not make monetary sence to weld them. The Rivets are about 2 inches apart, Keep in mind Large Aircraft that weigh 100 Tons are held together by Rivets, they are definately strong enough for most practical purposes.

John