Suggestions please (subframe)

[St Louis SHO]

I thought about what some people were saying about the aluminum subframe being a bad idea. Even though it was to be made by a reputable race car shop, it still would not give any more room, which is what I'm looking for. So, that brings me to a round tube subframe. Mine will be made of mild steel (it bends, moly doesn't) which will make impacts if any accepable. I am planning on using tubular lower control arms with heims, they will be adjustable for camber/caster.

I do have a question about ball joints. Is there a "drop in" style ball joint that has the same configuration as ours where it goes through the spindle? I planned on using 96+, but I don't know how to safley make the lower control arm take the stud of the ball joint without failure. If I can find an aftermarket joint that will go through the gen 1/2 spindle I can buy a cup to weld onto the control arm.

Input is appreciated, insults aren't.

Thanks

James

 

[LOUDSHO92]

Make it so you can drop the transmission without having to drop the subframe.

 

[naval-avi8or]

If you ever intend on driving this car on any public road I highly suggest that you forget of this entire thought. If you do make your own subframe beware that if you get into an accident you risk losing way more than your SHO.

 

[LJRuddy]

If you ever intend on driving this car on any public road I highly suggest that you forget of this entire thought. If you do make your own subframe beware that if you get into an accident you risk losing way more than your SHO.

Damnit guys.... James already got his ass chewed out on the previous thread. Freaking let it go! There are HUNDREDS of after market subframes out there for many many cars. Why can't the SHO be one of them?!?!?


Stop being the wheel chock of the SHO after market progress and let things be tried out. Who knows... Maybe this new subframe will be one of the best mods for the SHO since the Y-pipe.

Go for it James! Dont let the nay sayers bring ya down!

 

[Dedragonknight]

MAKE IT!!!! take a ton of freaking pictures, and let us know when your doing a gb

 

[DemonNeno]

Maybe Mike Kopstan can partake in this topic, but I believe a W-body control arm has a similar design, but i'm not sure how large the balljoint sleeve is. Time to start measuring stuff up!!

When you say you want to go with a heim joint, do you mean a sleeved heim joint or what? I would think this would broaden a unequal length control arm issue, but most importantly it would be disasterous without have a sleeved joint. Having to remove the control arm from the subframe to *guess* an adjustment, not to mention recalibrating a alignment machine afterward for accuracy's sake, would be a slow and annoying process. Again, i must say a cam eccentric would be best of both worlds.

When using tubular stock, don't forget it needs drainage holes! Some crafters choose to run without this, but any vehicle exposed to humidity or more serious weather would definitely benefit from this.

 

[Shoaz]

Input is appreciated, insults aren't.

If you ever intend on driving this car on any public road I highly suggest that you forget of this entire thought. If you do make your own subframe beware that if you get into an accident you risk losing way more than your SHO.

Damnit guys.... James already got his ass chewed out on the previous thread. Freaking let it go! There are HUNDREDS of after market subframes out there for many many cars. Why can't the SHO be one of them?!?!?

Apparently what is meant by "Input is appreciated..." is "Only positive input is appreciated..."

The tubular steel approach is a lot better than the aluminum approach IMHO, but you still need to bear in mind that the subframe on a SHO is probably the most critical part on the car when it comes to controlling the vehicle. Don't take this lightly at all.

Find a FWD car as heavy as the SHO, with as much or more power, and as heavy of a drivetrain, that has a tubular subframe and learn from that. If you can't find one that in itself might be an important data point.

 

[St Louis SHO]

What about a pro-street car that weighs 3600lbs and has a tubular steel front end? Quit trying to **** my idea. I'm not an idiot and niether is Jerry Haas. Thats all I can say at this point.

 

[Dedragonknight]

and as i said before, woot for new ideas. Even if this cannot be done in the end, its a great idea and will be a great attempt. Weight reduction is a big thing, and if it could open more possibilites for brake/suspension/ ect then why not try?

shotime- maybe something to think about would be a way to tie in the subframe to a full roll cage? I know on the mustangs sometimes they tie in the cage to the frame, and onto the front suspension, but thats a rwd app. Just an idea!

 

[JEM]

Apparently what is meant by "Input is appreciated..." is "Only positive input is appreciated..."

The tubular steel approach is a lot better than the aluminum approach IMHO, but you still need to bear in mind that the subframe on a SHO is probably the most critical part on the car when it comes to controlling the vehicle. Don't take this lightly at all.

Find a FWD car as heavy as the SHO, with as much or more power, and as heavy of a drivetrain, that has a tubular subframe and learn from that. If you can't find one that in itself might be an important data point.

Both front and rear subframes and all the suspension bits (including the struts and shocks) on late-model BMW 5ers are aluminum, of course they're RWD. I think the C5 and C6 platform Audi A6/S6/RS6 are aluminum too. I know all the suspension bits are.

Don't know about the Saab 9-5 but I suspect it isn't. Can't speak for anything Japanese.

I'm trying to figure out what the goal is here. You say you want 'more room' - for what? A different engine or transmission? If you use the Gen 3 lower arms the steering rack and control arm mounting points are going to be what you have to design around, and I can't see trying to do something with the Gen 3 lower arms without also using the aluminum Gen 3 spindle and ball joint setup. At which point you have to consider what you gain doing your own subframe versus just a Gen 3 conversion.

 

[Shoaz]

What about a pro-street car that weighs 3600lbs and has a tubular steel front end? Quit trying to **** my idea. I'm not an idiot and niether is Jerry Haas. Thats all I can say at this point.

FWD?

I'm not trying to **** your idea, and I'm not sure why you think I am. If you're not interested in constructive criticism why did you post asking for it?

Having spent 22 years as a practicing engineer an integral part of the process of getting something to turn out GOOD is to get as many qualified people as you can to pick it apart and find all the faults before it ever sees the light of day. I thought that's what you were trying to get accomplished, but the resistance to that that I'm hearing makes it seem as though you're just looking for people to validate your idea rather than criticise or improve it.

Both front and rear subframes and all the suspension bits (including the struts and shocks) on late-model BMW 5ers are aluminum, of course they're RWD. I think the C5 and C6 platform Audi A6/S6/RS6 are aluminum too. I know all the suspension bits are.

And if BMW's or GM's or Audi's engineering and manufacturing resources were behind it I'd not hesitate to put one in my car. I'm not sure I'd trust the typical commercial fabricator with such a piece, and that's really my only point.

 

[rudedog]

why was the other thread deleted?? i didn't even get to see an answer to my question, shit!!

 

[naval-avi8or]

I'm not trying to **** any idea and by all means I highly encourage those whom are trying to enhance the SHO's longevity in either replacement or performance aftermarket parts.

All I'm trying to do is make sure that he understands the legal implecations behind this particular part in which he is trying to hand craft. First it is a structural part, its responsible for 99.5% of the control of a 3500lb vehicle, the stock sub frame was engineered with years of R&D and approved by and tested by the NTSB to be safe. Now is this home made sub frame going to be backed by any of the above. As I stated earlier this member stands to lose allot more than SHO if involved in a wreck and the other party gains knowledge of the fact. Even more of a risk is to sell them to others and have it happen because he will hold the ultimate responsibility.

THIS ISN'T A Y PIPE WERE TALKING ABOUT HERE!

 

[DemonNeno]

I agree with SHOAZ, we need to accept viewpoints that have a valid concern with the frame. He's pointing out a engineering flaws rather than just plan ole wondering off-topic.

As for the safety issue, as long as the sub frame holds together, all we need to worry about is reinforcing it's mounting points so it doesn't rip out of the unibody due to being too rigid. Using full length sub frame connectors that directly connect the unibody from the sub frame-back to to the sub frame itself would be ideal, IMO.

You know, many chassis shops make units for anything you can throw at them. As long as the welds are strong and the fabrication isn't half assed (poor notching skills, etc..) it shouldn't be much of a failure concern. Now, poor crash testing, well that's a price you pay for a stronger but lighter unit... That hasn't been tested, thus making it a off-road unit by law.

What type of material are we considering here? The problem with moving to a tubular system is what you would consider using as far as gauge and material. I can tell you right now to stay away from chromoly units as there have been numerous incidents where welded joints have become brittle due to a lack of normalizing the materials. This is why the road race scene frowns upon this setup (although it's not outlawed). To use this, for its weight savings, as a sub frame would increase the chances of this being a disaster. Mild steel of a good gauge would work great, but now we're talking weight again. Compared to the OE's ~60# sub frame (i always thought it was remarkably light for what it is) I doubt you'll be saving much with a tubular unit, although it would definitely be much more rigid and the addition of being able to alter what suspension components connect to it would be wicked.

Instead of looking to reinvent a control arm, why aren't were just looking for control arms that are already invented that could be adapted? This would not only be beneficial to anyone who would be looking for a replacement part in some time of the future, but it'll also give you something proven to work. Tubular mustang control arms, perhaps?

Now that we keep boiling down to the safety issue, which holds a valid point, why don't we describe who this person behind fabricating these units is and his qualifications for a sub frame. Making sure all these units are load tested, checked for weld *********** and properly spaced, properly gauged welds are definitely a key part of making a successful product.

This brings us to the next question. How many people want a lightened sub frame strictly for weight savings? I'd say walk on home if this is what you're looking for. If you want a stronger unit that will help us work on our trannies with more ease, use a stronger control arm and allow us to push our vehicle's alignments more effectively, then I'd say this would rock!

 

[JEM]

As for the safety issue, as long as the sub frame holds together, all we need to worry about is reinforcing it's mounting points so it doesn't rip out of the unibody due to being too rigid. Using full length sub frame connectors that directly connect the unibody from the sub frame-back to to the sub frame itself would be ideal, IMO.

Let's review a couple facts here: once you do most anything to the car's body, you're throwing Ford's crash-test results out the window. That's true whether you're talking about lightening a Plus hood (ever notice they're designed to crush and fold the same way as the steel hood?) or adding subframe connectors (those rails in the floorpan are there to guide the front subframe under the car in a crash) and so on.

Now, once you accept that...

You know, many chassis shops make units for anything you can throw at them. As long as the welds are strong and the fabrication isn't half assed (poor notching skills, etc..) it shouldn't be much of a failure concern.

When you don't care about weight you use .120 or .180 mild steel and any competent welder can get a good joint. When weight starts to matter and you end up thinking about aluminum or chromemoly and optimizing wall thicknesses then the engineering requirements and fabrication skills get more important.

I can tell you right now to stay away from chromoly units as there have been numerous incidents where welded joints have become brittle due to a lack of normalizing the materials. This is why the road race scene frowns upon this setup (although it's not outlawed).

...which is where you find someone certified to do aircraft work, and most such welding is done with gas.

Compared to the OE's ~60# sub frame (i always thought it was remarkably light for what it is) I doubt you'll be saving much with a tubular unit, although it would definitely be much more rigid and the addition of being able to alter what suspension components connect to it would be wicked.

No, it's pretty heavy compared to some newer OE pieces, I'd bet the front subframe out of an E39 BMW probably weighs half that. But I'd never argue the subframes in an E39 are even a bit stronger than they absolutely need to be.

I think the most important starting point is to model the front suspension design and powertrain location you want. Then you need to lay out the subframe to support all that. Personally, relative to what little it takes to adapt a Gen 3 subframe I think it's a lot of work for limited gain unless the goal is to adapt a very different powertrain or you're really desperate to take weight off the car, but to each their own.

 

[St Louis SHO]

My goal here is to give myself about 3+ inches in the front and rear by using 1 5/8" round tube. It will be a little lighter, but not much with all the reinforcing needed. My other goal is to have a much stiffer LCA setup. Mustang arms might be nice, does anyone know if they use the same style ball joint?

And as for SHOaz concern with engineering flaws, he hasn't even seen what I plan on doing yet. Don't worry, I'll post pics of progress as it comes, THEN, you can chew my ass about it being unsafe.

 

[K-Dawg]

I plan to stick with my Gen 3 subframe, but I'd like to see something with raised control arm mounting locations to correct the geometry on a very low car.

 

[JEM]

I plan to stick with my Gen 3 subframe, but I'd like to see something with raised control arm mounting locations to correct the geometry on a very low car.

You're not going to raise the control arm pivot points in the Gen 3 subframe, about all you might be able to do (since you have to do surgery on the left-side frame rail for transaxle clearance anyway) would be lower the engine in the subframe and use thinner (solid) upper bushings to raise the subframe relative to the car.

 

[DemonNeno]

Let's review a couple facts here: once you do most anything to the car's body, you're throwing Ford's crash-test results out the window. That's true whether you're talking about lightening a Plus hood (ever notice they're designed to crush and fold the same way as the steel hood?) or adding subframe connectors (those rails in the floorpan are there to guide the front subframe under the car in a crash) and so on.

Now, once you accept that...

I agree and never have thought or said anything regarding this being untrue, sir.

The weight savings thing is definitely a nice deal, but I cream my pants thinking of a subframe that'll allow us to stiffen the cheesy front suspension setup we're stuck with. I wish ford used a strut-type similar to that of a Grand Prix (w/ 2 strut bolts @ the spindle rather then a single pinch bolt) and allowed for massive CASTER adjustments up top at the strut tower. That'd be sweet!!