New 3-pc crossmember - Thoughts?

[joescool2008]

Hey Phil, I've got a shop working on plans for tubular front control arms right now - even more front end weight savings! Some day we'll get someone to make a chomoly front sub frame, it's just a matter of time.

With a adjustable ball joint ?

 

[Ludachris]

With a adjustable ball joint ?

With plenty of adjustment points, and the Chrysler ball joint options that will allow road racers and autocrossers to use the longer stems to adjust roll center - yes. Check the tubular control arm thread in the Fabrication forum for info on how it will look.

 

[Phil1320]

Hey Phil, I've got a shop working on plans for tubular front control arms right now - even more front end weight savings! Some day we'll get someone to make a chomoly front sub frame, it's just a matter of time.

Very nice! I'd like to see those. I actually purchased a set of used Polk tubular control arms last year....they will be on the car for 2011. I think they lose 11 lbs. a side. Either way will be interested to see the pieces you are speaking of! Subframe would be killer....I remember Polk's design and it was sweet!

Phil, if your car is a track-only straight line car, I honestly wouldn't even bother with the north/south bars. I'd keep it as light as possible and run only the front bar. There's more than 50 DSMers out there right now running only the chromoly front bar and nothing else. Many of these cars still see street duty and I haven't had a single reported issue with any of them. This 3-piece design is targeted more toward the DSM that corners, or the guy that wants the extra rigidity at the expense of a few extra lbs. of weight.


I just got a call that the machinist is too busy to come through, and is returning the raw material to me. So, I'll be on the phone all afternoon until I find a replacement machinist. Life sure would be easier if I could afford to put my own vertical mill and lathe in my garage.


I'm shooting for no later than next week. I'll have an ad in the Freelancer section as soon as I get all the details squared away. I'll PM you when the time comes.

"I'm definitely interested in a 3-piece design for current drag racing and future road course work. " - you must have missed this in my other post, no biggie!

I definitely won't run the north/south for the drag strip, but with the possibility of road racing the car in 2012 I would want the accomodations for the north/south bars and you say that is available only if you purchase the 3 piece unit if I remember reading correctly, so that's probably the route I'll take. Although, I could just get your main bar and go back to the stock stuff later for road racing, but, that seems like taking a step back!

Damn, that sucks about the machinist......sorry to hear man. Must be a tad frustrating. At least it's winter in most places and the need for the part to be on anyone's car tomorrow I don't think is there. Good luck with getting someone that can do the work in a timely manner. I'm sure we'll all be here ready when you are.

 

[99gst_racer]

Yup, I did miss that line.


Bushings are being made tomorrow. A buddy came through and I dropped off the material last night. And I'm watching a few different lathes on eBay right now, so with any luck I'll be able to make these things myself within the next couple weeks.

 

[talontsi18]

Phil i'm glad to see that my post helped out. It will be a great addition to your car.

Paul I'm still on board when these are done as well. I'm excited to see some installed pics. Good luck with the machining.

 

[SupremeDsm]

I'm interested in these! They look great and it's a pretty good amount of weight savings! Pm me when I can buy them with a price please! Thanks great work.

 

[Phil1320]

Yup, I did miss that line.


Bushings are being made tomorrow. A buddy came through and I dropped off the material last night. And I'm watching a few different lathes on eBay right now, so with any luck I'll be able to make these things myself within the next couple weeks.

Wow, that's great! Very cool, on all counts!

Phil i'm glad to see that my post helped out. It will be a great addition to your car.

Paul I'm still on board when these are done as well. I'm excited to see some installed pics. Good luck with the machining.

Without a doubt, it did Thanks again for linking me up! I also feel it will be a great addition...follows my theme entirely. Not only because it drops curb weight, but, also because of always wanting to keep my engine set up as basic as possible while decreasing the amount of weight per HP. Now with a bit of engine work going on, and some decent weight loss as well, I'm hoping that I won't have to fight for another tenth next year....hopefully as much as .50 seconds will be there for me......

 

[dooblea]

I am also interested in a set of these! please pm me whenever they are up for sale with the price and shipping to 80233. finish is not an issue as i can powdercoat themn to match the rest of my engine parts. Thanks

 

[bastarddsm]

Hey paul,

Those look nice, but I don't they they going to be functional. The drivers side one needs to hit all of the mounting bolts The three bolts on the rear end of it form a brace for the front control arm mount. If this is not there the front control arm mount will eventually crack and break loose from the crossmember.

I think the hiems need to be replaced with a solid bushing at each mount bolt point on the cross members, then tubing conecting them together. I would like to see provisions for a stock style roll stopper. I'd be interested then!

 

[99gst_racer]

Thanks for the input.

Worst case senerio, users can simply cut off and use the ends of the factory crossmember to join both sides of the subframe. The crossmember bars would still fit fine.

 

[bastarddsm]

Yeah, I though of that too. It kinda defeats the purpose of buying some nice tubular stuff though. It ceraintly has to at least have parts of the originals. Mine cracked in less that 8000mi of street driving at 300whp power levels. Theres just not much support for that front control arm mount with out them. I bet that guy with the custom made crossmember that looks pretty skimpy will have problems like this.

I wonder what the original design intent of the stock braces was. As in what directions they were intended to improve rigidity. your pieces could certainly improve fore-aft rigidity, but they will have less side-side rigidtiy.

Don't get me wrong, I love what your doing, but I think more attention to the original design intent is nessecary. I also thing that provisions to use a stock style roll stopper would be nice, as I'll never run solid mounts. There is a couple of nice aftermarket roll stoppers out there too.

 

[99gst_racer]

Yeah, I though of that too. It kinda defeats the purpose of buying some nice tubular stuff though.

Not really. The factory north/south bars are somewhat dual purpose. They effectively brace the front and back of the subframe, as well as brace the subframe to the crossmember. So, think of it as using the ends of the factory bars to keep the subframe complete and braced. And the tubular pieces are more-so components of the crossmember system. Those ends of the factory north/south bars can't weigh more than 1.5-2 lbs max. And I wouldn't even go as far as saying they're necessary - simply optional. Like I previously mentioned, there's more than 50 guys out there running just the front bar with no parallel supports, and they're not cracking subframes. Many have been running them for the better part of 2 years now. If I redesigned the chromoly north/south bars to be 1-piece and hit all of the existing mounting points, the price of the system would increase substantially. Most people wouldn't want to pay $500+ for a system when they can pay around $350 for one that works just as well.

 

[Phil1320]

Not really. The factory north/south bars are somewhat dual purpose. They effectively brace the front and back of the subframe, as well as brace the subframe to the crossmember. So, think of it as using the ends of the factory bars to keep the subframe complete and braced. And the tubular pieces are more-so components of the crossmember system. Those ends of the factory north/south bars can't weigh more than 1.5-2 lbs max. And I wouldn't even go as far as saying they're necessary - simply optional. Like I previously mentioned, there's more than 50 guys out there running just the front bar with no parallel supports, and they're not cracking subframes. Many have been running them for the better part of 2 years now. If I redesigned the chromoly north/south bars to be 1-piece and hit all of the existing mounting points, the price of the system would increase substantially. Most people wouldn't want to pay $500+ for a system when they can pay around $350 for one that works just as well.

Yeah....gotta agree here. I know plenty of people that didn't run north/south bars even on street cars with no issues. I can't imagine what type of abuse said cars must have taken. Granted, I'm sure they(north/south) were designed with a purpose for sure, but to be cracking the subframe without them doesn't say much about the strength of the subframe at all, gotta be hittin potholes everyday or something. But, hey, everyone has they're own experiences.

 

[bastarddsm]

Ya, to each his own, I guess. I personally won't run with out them.

 

[HighPSI TSi Guy]

I wouldn't run without north/south support. I can tell just with DSMs on jackstands unbolting and bolting the bars back in under the weight of the motor the subframe is distorted without them.

 

[Phil1320]

Ya, to each his own, I guess. I personally won't run with out them.

Most definitely. I would not run on the street without them. Years ago, I broke a Bogart wheel and couldn't steer, was on the rotor and drove up on a curb. Had the north/south not been there the oil pan would have been smashed and the transfer case would have cracked--it currently looks like Taz took a bite out of the bottom of it. So, after that, for engine protection alone, I would not run the streets without the factory stuff due to it's width and ability to protect. For road racing, obviously, for torsional rigidity and for protection on off track excursions, the north/south would be on the car.

But, for drag racing, I don't think it's necessary at all. This is only my opinion and I'm only speaking for myself here and am not representing anyone else.

I wouldn't run without north/south support. I can tell just with DSMs on jackstands unbolting and bolting the bars back in under the weight of the motor the subframe is distorted without them.

Not saying this isn't true, but do these DSMs you're speaking of have full poly subframe bushings and motor mounts? That seems odd to me and I'm wondering if you aren't seeing factory rubber bushing flex---if these cars don't have subframe bushings at a minimum, I would test your theory on a car that does.

I will say that the factory subframe is fairly light---probably why some say there is no weight savings to go to a tubular subframe, however consider what this piece does and one has to believe that there is some pretty good strenght there: rear engine mount, steering rack mount, and control arm mount.

 

[99gst_racer]

I wouldn't run without north/south support. I can tell just with DSMs on jackstands unbolting and bolting the bars back in under the weight of the motor the subframe is distorted without them.

Everything distorts with the car on jackstands. The hood and the doors don't even close the same. I would expect chassis related components to distort even more-so. Fitting one of my chromoly crossmembers is FAR easier to do with the car sitting on it's tires, as apposed to jack stands. Everything just lines up much better.

 

[Pirrofab]

Everything distorts with the car on jackstands. The hood and the doors don't even close the same. I would expect chassis related components to distort even more-so. Fitting one of my chromoly crossmembers is FAR easier to do with the car sitting on it's tires, as apposed to jack stands. Everything just lines up much better.

Speaking of fitment issues I swore I read earlier that there is fitment issues between 90 models and 91-94 but couldn't find the difference is it in the location of a front motor mount bracket? Everything looks the same to me so some insight on this would be great.

 

[99gst_racer]

Speaking of fitment issues I swore I read earlier that there is fitment issues between 90 models and 91-94 but couldn't find the difference is it in the location of a front motor mount bracket? Everything looks the same to me so some insight on this would be great.

Yes, these are designed for 91-94 models only.

It can be made to work on a '90 model though. Several '90 model owners have simply drilled a new hole in the roll stop bracket to make it work. This is the only nessacery modification for a '90 model.

Pic:

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[Phil1320]

Do you have something that will enable me/us '90 guys to place that hole properly? Template? Or is it as simple as grabbing a '91+ bracket???

 

[e85_4g63]

Paul, we spoke briefly in PM's about this a while ago. I'm also ready to order when you have all the details ironed out. I know I had originally just wanted the roll stop single piece, but I've changed my mind and will be purchasing the 3 piece setup. Like others have said, please send me a PM when things are ready. Thanks in advance.

 

[99gst_racer]

Do you have something that will enable me/us '90 guys to place that hole properly? Template? Or is it as simple as grabbing a '91+ bracket???

I'll see if I can get one of the '90 guys to chime in with some details.

Paul, we spoke briefly in PM's about this a while ago. I'm also ready to order when you have all the details ironed out. I know I had originally just wanted the roll stop single piece, but I've changed my mind and will be purchasing the 3 piece setup. Like others have said, please send me a PM when things are ready. Thanks in advance.

Sounds good.

 

[Phil1320]

I'll see if I can get one of the '90 guys to chime in with some details.


Sounds good.

Ok, thanks. Just wondering if that hole has to be exact. I never knew that front bracket was different on the '91-'94 cars. If it is as simple as getting the bracket from the '91-'94 cars I'm sure I can source one fairly easily.

 

[HighPSI TSi Guy]

Do you have something that will enable me/us '90 guys to place that hole properly? Template? Or is it as simple as grabbing a '91+ bracket???

This is interesting. As many DSMs as I've dealt with over 10 years I'm surprised I've never ran into this bracket issue. I know when I swapped from MT to AT I changed the brackets on the block and everything fit up properly with my OEM MT 90 crossmember. Makes me think the 90 and 91 front should be the same, since my AT front bracket actually came off a 92.

 

[99gst_racer]

I'm not sure what's different on the '90 models. I assumed it was just the roll stop bracket, but I'm pretty sure someone reported that the '90 models use the same "347" bracket as the manuals. I don't have access to a '90 model to figure out the difference for myself.