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Tubular Rear Subframe Install

gofer

Moderator
8,133
1,338
Feb 18, 2006
South Gilbert, Arizona
Nearly a year ago Paul (99gst_racer) built me a chromoly tubular rear subframe that retains the rear sway bar and uses a thicker .095" 4130. I was fortunate enough to get the chance to test it for him but the timing wasn't the best and I'm just now getting around to install it.

Here's the thread that this stemmed from -- http://www.dsmtuners.com/forums/cus...-input-needed.html?highlight=tubular+subframe

A few specs on the setup for those interested.

The stock rear subframe (with LCA's and toe arms attached) weighs in at a 58.7lbs where as this .095" 4130 chromoly subframe (with LCA's and toe arms) weighs just 26.3lbs. Paul's first 4130 chromoly subframe was a drag only version with a thinner (.065") 4130 tubing that weighed 3.3lbs less overall and doesn't retain the rear sway. But, yes, this streetable tubular subframe saved approximately 32.4lbs. Paul also built this subframe specifically to use with the original Frontline Fabrication girdled rear diff cover.

Here's a shot of everything together, along with the FF diff cover, that I will be installing over the next few weeks. I'll be taking my time and documenting everything here as I go, I'd like to be done by August but you know how that goes.

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:dsm:
 

gofer

Moderator
8,133
1,338
Feb 18, 2006
South Gilbert, Arizona
I only had a few hours to work on it today, most of my time was spent moving things around in the garage to prepare for the removal of the stock subframe so I could install that work of art I got from Paul.

I got the rear tires off, the exhaust dropped, and pulled the rear sway bar before it was time for dinner. LOL

Here are a few shots of everything, hopefully I make some progress tomorrow. It's just tough right now since Arizona is seeing 105* temps regularly now, even 117* this Friday and Saturday. WTF

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:dsm:
 
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IrishBeatdown

Proven Member
585
4
Feb 3, 2012
Tucson, Arizona
That subframe looks incredible. I want me one of those. Probably a king's ransom for that, if its magnus counterpart is any judgement in terms of price. I hear you though, it is hard to make progress indeed. I was breaking an axle free under my car today, rolling around in the dirt. It was horrible with how hot it was. I'm so close to the end of my build and arizona is screwing it up right now.
 

gofer

Moderator
8,133
1,338
Feb 18, 2006
South Gilbert, Arizona
That subframe looks incredible. I want me one of those. Probably a king's ransom for that, if its magnus counterpart is any judgement in terms of price. I hear you though, it is hard to make progress indeed. I was breaking an axle free under my car today, rolling around in the dirt. It was horrible with how hot it was. I'm so close to the end of my build and arizona is screwing it up right now.
Pauls a cheap date and a cheap parts fabricator. ROFL

Pulling an axle out of the transmission is very humbling when you know nothing is holding the damn thing in, I couldn't imagine being crunched for time and out in the dirt and the AZ heat doing it.

I try setting up fans in the garage but it just feels like the old lady has her hair dryer on full blast hitting me in the face. I just have a big ass cup of water nearby and a clean towel to keep wiping off the sweat.

:dsm:
 

TSiAWD666

Supporting Vendor
2,650
887
Aug 15, 2003
Herndon, Virginia
When you install that diff cover I would put some teflon tape on the preload studs, and use some thread locker on the lock nuts. I had one of mine vibrate loose not long after install and then leak fluid. While on your subframe that's probably not a big deal as it was on mine as you'll probably be able to get a socket in there. On a modified oem subframe it means dropping the damned diff to re-tighten things. Very annoying problem that didn't need to exist. Hopefully this saves you a leaking diff :)

If Andrew had just designed the area around the lock nut so it was exposed enough to get a wrench on there it would be a non-issue. Tried to tell him but as I'm sure you all know he's about impossible to talk with unless you drive out to his shop :)

edit - your cover actually looks different than mine. Is yours a CNC'd one from a single block of aluminum, or is it welded together like the old ones?
 

gofer

Moderator
8,133
1,338
Feb 18, 2006
South Gilbert, Arizona
Love the subframe and wish he made them for 1g's, but I love how clean your garage is even more!
Thanks for the compliments on the garage, it could always be cleaner though. I'm in the market for some nice dark gray epoxy coat and shelves/cabinets for storage.
That sub frame looks like a lot of work to build. But if your losing 32 lb it should be worth it.
It does look like a lot of work but Paul made it seem easy in the few months it took him to design it. I'm looking forward to the weight savings but, more importantly, is the added bracing it provides to the rear diff.
I was tempted to get the magnus rear subframe, but now Paul is making both a front and rear subframe, I am most likely going to place an order with him.

(Also, subscribed)
I'd rather have Paul's tubular rear subframe and front k-member than a Magnus piece anyway, supporting the Freelancers. If you get the 2g front k-member be sure to ask him to build it for a Evo power steering rack, if you plan on keeping power steering.
I'm so jealous, definitely a nice looking piece. Can't wait to see the progress as it will be a great addition to your dsm.
Thanks for the compliment Ryuto.

:dsm:
 

gofer

Moderator
8,133
1,338
Feb 18, 2006
South Gilbert, Arizona
Looking good. Now we just need to get Paul to work more on them. :)
...maybe we can sway him to build a few more of these at the S.O. this year, I think we could take him. Problem is, Paul seems to always have a gun in every picture I've seen... ROFL
When you install that diff cover I would put some teflon tape on the preload studs, and use some thread locker on the lock nuts. I had one of mine vibrate loose not long after install and then leak fluid. While on your subframe that's probably not a big deal as it was on mine as you'll probably be able to get a socket in there. On a modified oem subframe it means dropping the damned diff to re-tighten things. Very annoying problem that didn't need to exist. Hopefully this saves you a leaking diff :)

If Andrew had just designed the area around the lock nut so it was exposed enough to get a wrench on there it would be a non-issue. Tried to tell him but as I'm sure you all know he's about impossible to talk with unless you drive out to his shop :)
Thanks for that info John, I'll be sure to do that.

I wonder if he corrected this issue when he designed the CNC version of the diff cover? Either way, Andrew is very hard to get in touch with as he seems so busy.

:dsm:
 

TSiAWD666

Supporting Vendor
2,650
887
Aug 15, 2003
Herndon, Virginia
Well, there are two issues, one with pre-load studs being able to loosen (because there's no lock washer or anything on the lock nut), and that on an OEM subframe unless you cut a huge hole for the super long pre-load stud you can't get a deep socket onto the lock nut to re-tighten things. Neither's fixed in the CNC version because the CNC version is what I have :)

You can't get a wrench from the side on the lock nut either because there's this shroud of aluminum surrounding it (the nut sits in a small well). I don't think the shroud needs to be there and if it wasn't you could tighten the damned thing whenever you wanted.

I can't tell in your pictures if you have the same design as mine but from the low-res pic it looks like you may not actually have the issue I'm describing, at least with shroud around the lock nut. Still make sure to find some way to keep the lock nuts from loosening, either loctite or a lock washer.
 

gofer

Moderator
8,133
1,338
Feb 18, 2006
South Gilbert, Arizona
I've got to make a trip to the hardware store to get some SS bolts, I think I'll bring the diff cover and get some lock washers too.

Thanks again, you saved me a headache.

:dsm:
 

renovatdkitchen

Proven Member
622
37
Sep 25, 2011
Toronto, ON_Canada
I'd rather have Paul's tubular rear subframe and front k-member than a Magnus piece anyway, supporting the Freelancers. If you get the 2g front k-member be sure to ask him to build it for a Evo power steering rack, if you plan on keeping power steering.

I would rather support him as well. Not that I have anything against magnus, but they make enough as it is (and they don't make a front subframe). I recall him talking about using a different rack. I'll be sure to mention it though.

Are you going to switch over to an evo 8 rear diff or keeping the dsm one?
 

gofer

Moderator
8,133
1,338
Feb 18, 2006
South Gilbert, Arizona
Are you going to switch over to an evo 8 rear diff or keeping the dsm one?
I'll be keeping the DSM diff. Tim (twicks69) is cutting 1.5 60fts making 9 second passes with a DSM diff, Evo 3 internals, a FF diff cover, and Boston Hatcher bracing on it. If it takes faster 60fts/ET's to break a supported DSM diff then I will never need to upgrade it since I don't plan on EVER going faster than a low 10 - well, I guess I'd take a high 9 too. LOL

:dsm:
 

viperlp01

Proven Member
2,521
75
Oct 9, 2006
Kalamazoo, Michigan
I'll be keeping the DSM diff. Tim (twicks69) is cutting 1.5 60fts making 9 second passes with a DSM diff, Evo 3 internals, a FF diff cover, and Boston Hatcher bracing on it. If it takes faster 60fts/ET's to break a supported DSM diff then I will never need to upgrade it since I don't plan on EVER going faster than a low 10 - well, I guess I'd take a high 9 too. LOL

:dsm:

Not to knock on Tims accomplishments but Devins 2g is running a 2g diff and is cutting 1.3 60ft and is going mid 8s....
 

gofer

Moderator
8,133
1,338
Feb 18, 2006
South Gilbert, Arizona
Not to knock on Tims accomplishments but Devins 2g is running a 2g diff and is cutting 1.3 60ft and is going mid 8s....
Even more reason why I'll never entertain moving to a different rear diff. LOL

I knew Devin was running the CNC diff cover as I saw a picture of the car from his top speed runs, just not familiar with his setup to comment on it is all.

:dsm:
 

gofer

Moderator
8,133
1,338
Feb 18, 2006
South Gilbert, Arizona
It might not look like much got done but I put in a few hours today getting the suspension parts dropped. The LCA's are completely removed but I don't have a spreader for the toe arms, I'll rent one from O'Reilly's on my way home from work tomorrow. I'm just happy the axles are sliding freely in the hub, I've seen so many posts with them seized I was a bit worried.

Plan is to drop the e-brake cables, toe arms, driveshaft, and oil in the diff tomorrow.

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:dsm:
 
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untouchablecc

10+ Year Contributor
852
12
Mar 21, 2008
Mt. pleasant, Pennsylvania
This is baller. I can't wait to see it finished. I love weight reduction and over all suspension improvement for handling. I am curious as to how much this cost, the magnus one is a bit steep for something I just want to daily and rarely auto x or anything where I would use that.
 

greengoblin

Supporting Vendor
1,573
391
Mar 10, 2006
McKinney, Texas
The Frontline FAB diff cover will not work with the tube subframe. I talked to Andrew about it and I doubt he is going to make any chance so it can.

When you get the subframe dropped can you get me a few good pics of the fuel tank strap mounting points. The straps have "hooks" on them where they bolt to the frame under the rear cross member. I have been wondering about what if anything they hook on too.
 
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