custom subrame build for SC2

[Mark R]

OK, I know this is WAY off topic for a GT40 forum, but honestly... I see more quality fabrication here than anywear else I frequent. So here goes....

When I am not working on my Ford/Mustang projects, I rebuild/rehab S-series Saturns. Mostely for my 3 (driving) kids and an airport commuter for me.

Since moving up the the Chicago area, i have noticed a significant issue with these little cars. The front sub-frames tend to rust out and cause issues with the motor, tranny and LCA mounts.

You can drive down to Florida and drive back a used subframe, but thats a big hassle and I see many project cars up here in the rust belt that could be saved with a decent replacement option.

So a project I have been wanting to try out is to build a tubular replacement subframe that could be used as a stock replacement.

I know some might consider this a waste of time/effort, but my son is about to take a welding class and I have been wanting to get into welding/fabrication too. So, this would be a relatively easy project (I think) to start with. And: BTW, I currrently have two SC2 cars that would benifit from this project. Who knows how many I might need down the road.

Who knows when I will get to start working on building what i really want, which is a full build like the Apex or a 40(eventually).

I plan to start by building a wood jig to get all the stock mounting points locked in. From there I would work to duplicate the factory design, trying to improve the strength and reduce weight wherever possible.

I see no reason to change any of the mounting points, although raising the steering rack by .5-.75" might not be a bad idea. 1.4" lowering springs are pretty common for these cars. Espectiall the SC2 (coupe) version. So... I would probably keep mounting dimensions the same for now.

It seems like mild steele is a typical material I see used for this. Any thoughts??

 

[Dave P]

What you need is a large can of Iron Moth Killer. Those pesky critters ate my truck I drove to North Carolina in clear up to the door handles. It was a friendly truck it waved it's body panels at every one that passed by. :laugh:

All joking aside any you can do it a wood fixture would work ,steel would be better.

 

[Mark R]

Thanks for your thoughts, Dave! I know a steel patern or jig would be better, but I think wood will work and will make getting this started a bit easier.

Based on the builds I follow here, I think quite a few folks could pull this off with eyes closed and one hand behind their back.

I have a lot of experience with car builds. Mostely vintage mustangs. But virtually no fabrication, so I am realy eager to start building something useful once we get a welder up and running.

Please take a look at the attached subframe and let me know how you would approach this. Keep in mind this is for a small 4cyl FWD car that weighs >2,500#.

I hope I didn't offend anyone by posting up pics of a lowely Saturn frame? Just think of this as my pre build practice.

 

[Dylan]

No pictures came through, unfortunately.

Also, why are you raising the steering rack, and what are you doing to correct the resultant geometry changes?

 

[Mark R]

The pic was attached to the first post. Are you not able to open it?

I do not plan to change the geometry. At least for now. I was only theorizing that raising the rack would compensate for H&R 1.4" lowering springs that are common. I have heard some accounts of minor bump-steer issues, but its not a huge deal. My assumption was that raising the rack would partially correct the tie rod angle and remove any bump-steer associated with the lowering springs. **this is not a primary goal here. Just a thought that might be worth doing.

No pictures came through, unfortunately.

Also, why are you raising the steering rack, and what are you doing to correct the resultant geometry changes?

 

[Dylan]

My apologies, thought there was supposed to be a second picture.

As far as the rack goes- a change in spring height does not mean a corresponding change in rack height. A proper rack position should present good bump steer qualities throughout the range of motion, regardless of what ride height the springs put the car at.

 

[Mark R]

As far as the rack goes- a change in spring height does not mean a corresponding change in rack height. A proper rack position should present good bump steer qualities throughout the range of motion, regardless of what ride height the springs put the car at.

Ok, I will deffinately plan to leave all the dimensions in the stock position. I have just heard so many comments over on the mustang and SVT forums re lowered cars having issues with bump-steer, I thought it might be a good idea to correct for that on the rack mounts. No big deal... That was a secondary objective, at best...