A couple of you guys are making your own cross members for more duals.I want to do one too but the thing that bothers me is the force of the torque arm pulling up and down on the trans-tail shaft might rip the X-member apart.Do you guys think its safe in the long run?

 

i think it could be made to be safe...


im going to be attempting to make one for a T56 myself in a few months.... basicly, i want to be able to have longtubes without ground clearance issues... i figure that if the X member tucked up enough, the pipes could squeeze out the back and into the tranny tunnel...

 

btw, im just going off intenet pics to tell..... i dont have the long tubes installed yet, and i still have to get a T56...

 

I should have some road time on mine soon, I'm still trying to find time to finish installing new front springs to gain some ground clearance. I fabbed this x-member up in about a week of evenings. Seems fairly stout, but some good wheel hop should be the true test.

If all goes well, I'll pull it off and powdercoat it.

Drew
'89 IROC L98/M6

 

Damm Drew... that's anexcellent x-member setup

I spent about 2 hours on mine (wasn't going for fancy)


I have about 150 miles on mine so far of driving around short trips in the neighborhood and a little beyond (what's "safe" for driving illegal). In those miles, I have hammed my car pretty much every trip with no signs of problem. I can nearly gaurentee (as long as the welds are good) the yours isn't going to fail Drew.
When it comes down to it, the penetration (heat) of the welds are going to be the biggest strength factor of the x-member. When using a crap welder like mine, ever weld jount was ground to a 'V' to assure good penetration, fill and heat.
The rear tugging at the trans (via torque arm) isn't going to be nearly as bad on the x-member as how the motor/trans is constantly twisting on it. Any time your on the gas (cruising) bumps and irregularities in the road constantly twist on the drivetrain. You can easily verify this if you have a standard shift .

 

If you use heavy enough metal there won't be a problem with breaking it, of course it has to be welded properly and braced for rigidity...

 

I just fabbed up my homemade T56 crossmember last week... I had a 3" custom Y-pipe made for it on Friday and none of it is as low as the collectors . I would say it is a good 1/2-3/4" higher a the lowest points and that is where I had the guy put 3-bolt collector flanges towards the back of the Y-pipe so I can take it apart when the trans needs to come out. The tubing is a good inch higher than the collectors of the headers. My car in general is still pretty low to the ground, but it also has the Eibach Pro Kit in it that has been massaged a little in the front...

For the crossmember I used angle steel for the end pieces just like drews did but I turned them so the part that is perpendicular to the ground is towards the outside of the car on both sides. Then I used one piece of 1 1/4" x 2" rectangular steel tubing for the crosspiece. I cut pie chunks out of the tube and bent it and welded it to make it go up on both sides. The tubing was welded flush against the driver side angle piece and then I made a few small adapter pieces to fill the gap on the passenger side one that was formed by the angle that side of the subframe rail is in comparison to the driver side. Then I welded it to that angle piece. Then I made a little pad for the mount that extends forward and down for the mount to rest on. The pad has braces welded to it on both sides that hug the sides of the mount and triangulate the structure of the trans mount to the cross bar piece. I tacked everything under the car and then took it off the car and ran full length welds on every joint.

I attached a rough layout of how I did mine but basically I went behind the mount with the cross piece instead of going straight across and under the mount itself. If you make the mounting pad strong enough it should be plenty strong...

I also don't have to worry about the forces of the torque arm since mine mounts to my SFCs (S&W)....

I want to powdercoat mine as well but I have other things to worry about like tuning this thing and putting some miles on it as much as I can before winter sets in....

 

Congratulations Drew
thats a Great Design!

I made a tubular one a while back using angle steal for the ends-
its light and strong enough to hold the tranny - I dont use the TA

But yours is the best I've seen-
good luck e-man

 

.

 

Matt do you have any pics of the S&W subs and torque arm installed?

 

as long as the welds are good it will hold,i have been running mine for a year,with no problems,and big mods,drew that is the best crossmember that i have seen,nice job

 

Well Drew, how did the X-member hold up? Did in bend at all on any hard launches?

 

Yep, things seem to check out just fine! I have done a decent amount of beating on the car since installing the headers/exhaust/x-member and I was surprised at how solid the shifter feels. There is definitely no more tranny movement than there was before and no indications of any cracking or imminent weld failure (I preheated to be sure).

Thumbs up!

Drew

 

Awesome Drew!

Do you have pics of your completed exhaust?

 

This is one that I whipped up for mine in one evening for my TH-350.......

 

here it is!

 

 

1QwikZ.....what would getting you to make something like that up for another person actually run them? I have an auto in my car and could really use one of those...if you catch my drift

 

I had one made at a local welding shop, but it is pretty ugly. It tucks up and gives a little more room for the exhaust, and is beefy as hell. Eventually I would like to have one made that is a bit more eye appealing, but my car would have to be jacked up for people to see it because it tucks up, and the exhaust blocks any of it that you would be able to see.

Ben

 

ttt

anyone else have a price on making one of these for a 700R4 or TH350 trans for me?

 

looks real good drew

 

1bad91Z,

Yes, I do have a couple shots of the completed exhaust located here:

Drew's Exhaust

Ground clearance seems to be good, I haven't whacked a collector yet even with the car slightly lower than stock. The lowest point of the system is the pax side of the y near the tail of the tranny.

 

So drew, do you think you could make another one of those. I have one that is functional and clears my exhaust, but yours looks real nice. If you would make one what would you want for it? You can pm me if you would like.

Ben

 

Nice exhaust Drew!! I will end up running mine like yours, only madrel bent though.

Killer setup man, thanks for the pics!

 

Thanks,

I did use about 4 aluminized 3" 90-degree tight radius mandrel bends for the y-pipe, so it's probably better than what any shop in Austin would slap together. I don't know of any local places than can do custom mandrel bending I imagine that may require a trip to SA or Houston.

Drew
'89 IROC L98/M6

 

Sorry man, I missed this Q... I have this one pic I took of my Y-pipe that shows the crossmember and driveshaft loop sort of but that is about it. I just got a digital camera so I will be able to take some more when the weather warms up and the GTA comes out of hibernation....lol.



There are some more pics of my Y-pipe setup in the Hooker LT sticky post if ya'll are interested.....

 

Thanks for the pic Im looking foward to seeing pics of the S&W subs installed.

 

That's really an awesome job.I remember reading an article about a tunershop named Nunzi in Brooklyn N.Y. that offered those for third-gens.The design looked alot like yours from the picture i saw in the article.I think they used a 350 automatic trans. on the Firebird they were building.I think somebody could sell quite a few of these from the sound of things.I'm surprised the aftermarket hasn't picked up on it.

 

I think this is an interesting approach, although this is on a C3 which is an entirely different animal, of course.

<img src=http://temp.corvetteforum.net/c3/budman78/corvette_2003_023.jpg width=50%>

 

I could see that causing some rattles.

 

Looks like a reproduction of my dad's '63 Vette frame.

 

Apeiron's picture there...I was thinking the same thing about noise and rattling. How would you prevent that? I'm sure you can't use bushings on exhaust pipes because of the heat, so what would you use?!?

 

Make sure it's well supported and you have adequate clearance would be about all you could do I suppose.

 

I have a couple of x-members built and one is available. I'm building more so if anyone else wants one PM or email me, privately.

Checkout the pix here.

These are for OEM T56 retrofits.

Drew
'89 IROC L98/M6

 

looks pretty close to the one i made but mine is one peice between the frame rails. nice

 

It baffles me that these cars are more than 20 years old in design and the aftermarket STILL hasn't created stuff like a dual exhaust crossmember Maybe I should fab one and sell it?? heheheh.

BTW you don't necesseraily need to fab one if your on a low budget and want true duals. I did mine by bending on the stock cross member until enough clearance was made.

 

So are you selling these?? How much? I know there are alot of ppl that would buy them... I'm too lazy to make my own right now. Please let me know.


Thanks!

 

anyone ever tried this with an auto tranny.. like the TH400 ?

i might have to get under the beast with the measuring tape and see about this...Vacuum modulator and a few other misc things might get in the way tho

 

Yes, as folks order them I make a batch and then once the batch sells out I wait until someone else orders another one and then start again.

Drew
'89 IROC L98/T56

 

Check your PMs..... how much? Let me know, thanks!

 

Looks like i am going to make my own, and to make things better, I am using solid motor mounts so I can eliminate the rear mount (bolt it to the crossmember) all together!