Sub Frame Connectors

It was suggested to me that adding Sub Frame Connectors (weld-In type) will help especially with my 94 Z28 convertable.
????? What are they and what do they do. How much can I expect to pay????

Thanks

Hi, me again. I'm the one that recommended the subframe connectors in the first place. :)

Your Camaro has a front subframe and a rear subframe, both of which are welded to the car's unibody. The engine, transmission, steering, and front suspension ride on the front subframe, and the rear end and rear suspension ride on the rear subframe. The body itself can flex, which means that the front wheels and the rear wheels can move relative to each other. This is bad for handling, and also is one major cause of interior squeaks and rattles. On a convertible, there is no roof structure contributing to the body's rigidity, so body flex is even more pronounced.

Subframe connectors are long metal tubes with mounting plates on either end. They come in pairs -- one for the left and one for the right side of the car. One end welds to the front subframe, and the other to the rear, linking the two subframes together. This helps eliminate the body flex.

http://www.afterthoughtsauto.com/bmrsubcon4th.html

They're a bit under $200.

JakeRobb,

Thanks for the info. on the sub frame connectors. I wasn't sure if I should have asked in the new members reply or the suspension thread. Great info and easy to understand. It sounds like a straight forward mod.

NS

http://www.bmrfabrication.com

I used BMR round tube for clearance on my 93Z..... This is their home page...:)

http://www.bmrfabrication.com

I used BMR round tube for clearance on my 93Z..... This is their home page...:)

BMR doesn't appear to sell a boxed tube connector for convertibles, so I didn't bother to explain. :)

I don't have a vert but it has been the best thing I did to my car. If your not sure it helped, jack up the car before an after from the same spot. With a jack on the sub frame just behind the front tire it will lift three wheels off the ground.

BMR doesn't appear to sell a boxed tube connector for convertibles, so I didn't bother to explain. :)

Wasnt sure... Havent been to the site in a few years.. :);):p

The BMR site shows just one style for "verts." It does not indicate bolt on or weld type. They also appear to be very different. Take a look and let me know what you think.
Because I will not be racing, is the bolt on good enough. JakeRobb suggested the weld on.
Thanks again

NAS

How do the ones linked here compare with the diamond design ones and would clearance be an issue on a non-lowered car?

The BMR site shows just one style for "verts." It does not indicate bolt on or weld type. They also appear to be very different. Take a look and let me know what you think.
Because I will not be racing, is the bolt on good enough. JakeRobb suggested the weld on.
Thanks again
I prefer weld-on. This is your car's frame we're talking about. Can you think of any car, ever, in which the frame was held together with bolts? I can't. They're always either formed in a single piece, or welded together.

A bolt-in set would still work, and would still give you some of the added strength, but welding will give you more strength. Also, weld-ins usually cost less. :)

How do the ones linked here compare with the diamond design ones and would clearance be an issue on a non-lowered car?
What are the "diamond design" ones?

Clearance is always an issue on an F-body, lowered or not. ;) However, subframe connectors shouldn't change that.

so you would recommend buying a set of weld ons and getting them put on? I dont weld myself so i would have to pay someone - what sort of price would one expect for a decent job and where could i go to get it done? baltimore md area here, anyone know anyone that does good work but not too expensive?

so you would recommend buying a set of weld ons and getting them put on? I dont weld myself so i would have to pay someone - what sort of price would one expect for a decent job and where could i go to get it done? baltimore md area here, anyone know anyone that does good work but not too expensive?

Any exhaust shop should be able to weld them on for you. I would expect that they'd do it for $50 or so.

I've heard some people say that you should pull back the carpet inside the car near where the connectors attach to the frame, since heat from the welder can come through and melt/burn the carpet. BMR's installation instructions don't mention this, so I can't really say how important it is.

What are the "diamond design" ones?

Clearance is always an issue on an F-body, lowered or not. ;) However, subframe connectors shouldn't change that.

Well, I don't think anything can be any lower than the flange on my headers, which is less than 2" off the ground. :eek:

These (http://www.hotpart.com/shop/index.php?l=product_detail&p=56) are the subframe connectors that I'm considering...listed as "diamond" design.

These (http://www.hotpart.com/shop/index.php?l=product_detail&p=56) are the subframe connectors that I'm considering...listed as "diamond" design.

I think "Diamond" is the manufacturer. Those are called three-point subframe connectors, and they add an additional point of connection with the vehicle. This seems like a good thing at first, but they don't specify what that third point is. It's not the frame of the car, since there is no frame anywhere near where that point would be. Maybe it's the transmission cross member?

If anyone knows where the additional connection point is for 3-point SFCs, and especially if they have the engineering background to comment on whether they actually add value, please comment. :)

I have the 3 point UMI subframe connectors. They are bolt in and the 3rd point is the crossmember. With stock components this may not work as well but I also have a UMI tunnel mounted torque arm which has a much stiffer crossmember included. With the combination of these 2 things the left and right side of the car are now tied together giving me a much stiffer chassis overall. I can't really elaborate on how much stiffer since I did several other suspension mods at the same time but it is definitely better than a 2 point style subframe connector. The only issue is that you loose some ground clearance, even though the UMI piece is very well designed, the crossmember is still an issue with scraping. If your primary focus is on drag racing, 2 point will work fine, if it is handling, 3 point is the way to go.

I think "Diamond" is the manufacturer. Those are called three-point subframe connectors, and they add an additional point of connection with the vehicle. This seems like a good thing at first, but they don't specify what that third point is. It's not the frame of the car, since there is no frame anywhere near where that point would be. Maybe it's the transmission cross member?

If anyone knows where the additional connection point is for 3-point SFCs, and especially if they have the engineering background to comment on whether they actually add value, please comment. :)

The "Diamond" SFC's look a lot like the old SLP SFC's.

I have Ken_Brown (I think not in bizz anymore?) D_diamond subframes. Welded. They tie front motor compartment + rear pan rails, and center pan + rockers (3 places) all together. Very rigid. I also have the KB street cage on top. I do not know who sells them. Maybe SpeedInc in Chi_town. I purchased them in 1998 (97ss M6 383ci D1). They also allow you to remove the eng and trans with good clearance. B.

I have BMR weld ins, if i was buying sfc's again they would be UMI's 3pt's.
:p

hey so if i get them i would have to cut the welds to pull the motor/ drop the subframe?

No, they don;t come that far forward.