Tubular rear subframe - Input needed

[99gst_racer]

EDIT: 8/2/17. Info on these here----> http://www.dsmtuners.com/threads/2g-tubular-rear-subframe-kit.513217/

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I'm going to start building these very soon. I just want to gather some opinions and get some input from you guys before I begin the prototype.

Material: Chromoly VS Mild steel. they're both great materials for this project and they're both strong enough. I plan to use chromoly tubing simply because I can get it with a slightly thinner wall thickness, which will save a bit a weight and without compromising strength. Would most people prefer chromoly over mild steel anyway?

Control arms: I had originally planned to build the subframe to accept stock control arms, but in retrospect, I'm thinking about discarding that idea. Chromoly arms will be smaller and lighter, and won't add much to the overall price. I figured most people will want the moly arms to go along with it anyway, and that will also allow me to "tighten up" a few areas of the design. Thoughts?

I plan to make it to where it will fit with the factory gas tank. It will brace the differential much better than from the factory; both sides of the pinion area and 4 points on the diff cover.

Any questions, just ask. And if you have some input or have a suggestion, post it up! I'm hoping to get started on the prototype next week.

 

[bmoha7321]

It'd be a dream part! You do awesome work! Cro moly of course!
Uh... How different would you make the control arms?

 

[DsMWookie]

Paul,

How much is chromoly a foot versus mild steel? I know here it is a substantial difference. If the tubular rear end only requires a nominal amount of tubing then that is not a large factor. Something like a cage though it adds up pretty quickly.

 

[Flash]

It's a good idea. My best advice is to build the best piece you can. The best quality part will attract the best quality customers. You don't want the typical penny-pincher DSMer as your core customer- you won't stay in business and you'll be producing junk thus ruining your brand image.
I would also suggest offering a service to powder coat it (for added convenience)- work in additional margin.

 

[91stocker]

It's a good idea. My best advice is to build the best piece you can. The best quality part will attract the best quality customers. You don't want the typical penny-pincher DSMer as your core customer- you won't stay in business and you'll be producing junk thus ruining your brand image.

Have fun competing with Magnus then. Their rear subframe is a piece of art.

 

[99gst_racer]

It'd be a dream part! You do awesome work! Cro moly of course!
Uh... How different would you make the control arms?

Thanks man. The arms would be chromoly steel and heim joints, pretty much just like the ones in the Magnus kit.

Paul,

How much is chromoly a foot versus mild steel? I know here it is a substantial difference. If the tubular rear end only requires a nominal amount of tubing then that is not a large factor. Something like a cage though it adds up pretty quickly.

I can't publically discuss my pricing, but I can say that chromoly costs about 3x as much as mild. But, it's doesn't add up to a huge difference in the end. 1.250" diameter is a good amount cheaper than 1.625".

 

[99gst_racer]

It's a good idea. My best advice is to build the best piece you can. The best quality part will attract the best quality customers. You don't want the typical penny-pincher DSMer as your core customer- you won't stay in business and you'll be producing junk thus ruining your brand image.
I would also suggest offering a service to powder coat it (for added convenience)- work in additional margin.

Have fun competing with Magnus then. Their rear subframe is a piece of art.

Just you guys wait. I wouldn't even attempt this if I wasn't confident I could build one of the best on the market. The Magnus kit is very nice, but I see room for improvement in design and price.

 

[bmoha7321]

Have you seen the parts he's produced? They are art. Jus sayin.

 

[bastarddsm]

If your going through this effort, I'd suggest making something that could use a different center section. The dsm stuff is junk, and parts are drying up for them. Ya, you can use EVO8/9 stuff, but that isn't without faults either.

 

[SupremeDsm]

Hey paul. Do you plan to make this for the 1g? If so you already know I want one for the project. Btw ill be sending you that money friday for the front cross member. Thanks it looks great. Your work is top notch.

Chris

 

[vr4scott]

Chromoly is the way to go for something structural like that. PM me a price when you figure it out.

 

[greengoblin]

It needs to be stiff enough for the road coarse.

The suspension pick up points should have the option to be moved to correct suspension geometry on lowered vehicles.

Sway bar option is a must. It would be awesome to see it work with a splined style sway bar since they are so easy to get in different spring rates.


If you can do the chromoly and do it well then go for it.

After you build a rear you need to build a front one that does everything the rear one does plus give option for different steering racks.

Kevin

 

[99gst_racer]

If your going through this effort, I'd suggest making something that could use a different center section. The dsm stuff is junk, and parts are drying up for them. Ya, you can use EVO8/9 stuff, but that isn't without faults either.

The issue is that 99%+ DSMers are running factory rear differentials. Not that a better rearend is a bad idea; it's just that I want this subframe to be a direct bolt on for our cars are our components. Also, my fixture is already set up for the 2G rear diff.

Another cool idea would be a bolt-on 8.8 rear axle/subframe kit for the drag race guys.

Hey paul. Do you plan to make this for the 1g? If so you already know I want one for the project. Btw ill be sending you that money friday for the front cross member. Thanks it looks great. Your work is top notch.

Chris

Sounds good.

I'm not sure about 1G stuff. I'll consider it after my first run of these.

Chromoly is the way to go for something structural like that. PM me a price when you figure it out.

Actually, mild steel is plenty strong for something like a subframe. Some fabricators actually prefer it. Although there's no denying that moly is stronger. In my opinion, mild is plenty strong and chromo is just stronger yet.

I'm going to put together a group buy after I crank out and test the first two. Stay tuned!



Kevin, I'll send you a PM tonight when I get home.

 

[91stocker]

How about making a bolt on kit for a 8.8 rear instead

 

[Ludachris]

Paul, maybe what you do is create provisions for a couple other rear ends. That way the user can go back later and buy an "installation kit" for a different rear end.

Just wish this was for the 1g... and better yet, for the front of the car on a 1g. Everyone knows more people race the 1g's!

 

[bastarddsm]

The issue is that 99%+ DSMers are running factory rear differentials. Not that a better rearend is a bad idea; it's just that I want this subframe to be a direct bolt on for our cars are our components. Also, my fixture is already set up for the 2G rear diff.

Another cool idea would be a bolt-on 8.8 rear axle/subframe kit for the drag race guys.

Oh I agree that most would need it for stock stuff, but the problem is all the stock stuff is worn out, and the parts to fix an oem dsm rear diff are nla. You can put an EVO carrier in the dsm case, but you then need the EVO inner cups, and you still stuck with a small carrier that has minimal clutch pack area for the posi unit.

I can see your point tho too, there isn't much call for somthing like a 8.8 center section in these, and the custom axles wouldn't be cheap.

Paul, maybe what you do is create provisions for a couple other rear ends. That way the user can go back later and buy an "installation kit" for a different rear end.

That's not a bad idea. If you did it like a the cobra I'm building and had rubber isolated mounts for the diff, you could solid mount the subframe to the car, and keep some of the driveline noise out of the car.

Just wish this was for the 1g... and better yet, for the front of the car on a 1g. Everyone knows more people race the 1g's!

A 1g one would be super easy. I'd probably have already done one, but I'd rather put the effort into a 8.8 swap.

 

[jtmcinder]

If have raised the inboard pick-up point for the front lower lateral arm, then go ahead and raise the rear one, too. But try to keep the front roll center at least as high as the rear. Stink-bug mode!

 

[DsMWookie]

P.S. Paul where is the 1g K member love? That has demand pretty pent up judging by the other threads

 

[bmoha7321]

I don't understand what you just posted. You quoted my post. In my post I'm saying Paul's work is art. I don't know who Marco is.

 

[turbosax2]

I would say definitely yes to new control arms. Don't bother with the stock ones. And if we can avoid reaming the knuckles, even better.

And agreed that sway bar attachment points must at least be an option.

 

[DsMWookie]

I don't understand what you just posted. You quoted my post. In my post I'm saying Paul's work is art. I don't know who Marco is.

Marco is the owner of Magnus...simple mistake. I thought you were just nut swinging off of him as though Paul could not compare. If that was the case I just felt it was discouraging to Paul which would suck because he is taking the initiative to bring a product to market at a reasonable price with hopefully equal or superior build quality.

Cliff Notes: I make asshat of self

 

[mike96]

That's not a bad idea. If you did it like a the cobra I'm building and had rubber isolated mounts for the diff, you could solid mount the subframe to the car, and keep some of the driveline noise out of the car.

Maybe leave enough room in the mounts for the rear diff and have it so that brackets or spacers are needed to fully mount the diff. That way if someone so decided to they could just have a new set of brackets/spacers made up to mount an evo or 3000gt rear diff or even something from a totally different manufacture even. The new camaro rear end is IRS and can handle quite a bit of torque... Could make RWD conversions for drag a lot easier. Not sure you could get the correct ratio in that rear end to match up with the DSM AWD trans.

 

[turbo23]

You do know, that the extra work that would go into making different rear diffs work would be crazy.. not only would he have to figure out how to mount the diff, he would first have to buy the other diffs, then see about how to modify the flange to work with our drive shaft.. He'd also have to find a fix and then a source for axles. The distance for the front of the driveshaft to the center of the axle cups my be different which would mean a different driveshaft, and re centering the diff for and aft.. there is alot of work being put into this already, at this point making more work for Paul is probaly not a good idea.. IMO let Paul build a few, and then ask for changes!

 

[Tyeler18]

If you decide to make a 1g kit I'd be in assuming its before next fall. I plan on building a chromoly front/rear subframe in my chassis fab class next fall.

 

[mike96]

You do know, that the extra work that would go into making different rear diffs work would be crazy.. not only would he have to figure out how to mount the diff, he would first have to buy the other diffs, then see about how to modify the flange to work with our drive shaft.. He'd also have to find a fix and then a source for axles. The distance for the front of the driveshaft to the center of the axle cups my be different which would mean a different driveshaft, and re centering the diff for and aft.. there is alot of work being put into this already, at this point making more work for Paul is probaly not a good idea.. IMO let Paul build a few, and then ask for changes!

I think what I posted was miss interpreted, maybe.?. I am not suggesting that Paul incorporate the ability to mount all those different types of diffs into the design of the subframe. Simply that it might be a good idea to leave enough room in the subframe around the diff and make the brackets that bolt the diff to the subframe removable. That way if someone purchased his subframe a wanted to swap in a different diff they would have the room to do so and posibly not have to modify the subframe itself, just the mounting brackets. So the only extra work on Paul’s end would just be the brackets for the factory diff... Sorry if I made my other post a little misleading.