Is it bad to remove a set of weld-in SFCs?
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Is it bad to remove a set of weld-in SFCs? I wanted to get a new set of SFCs (tubular/chromoly) because mine are boxed and made of steel, and I was told that by cutting/torching/etc. to the body/frame is bad. Im not sure what they meant by that, but I really would like to switch SFCs and I really think its worth it. What kind of "bad" things can happen by removing a set of SFCs that are welded in and replacing them with another set of weld-in SFCs? Whats the easiest/safest/most effective way to remove them? A torch would be the fastest but also the messiest! Most likey it would take longer because I would be under there grinding all the excess. A bandsaw would be nice, but I dont know how I would position it to do it. Any ideas? Thanks
Re: Is it bad to remove a set of weld-in SFCs? A plasma cutter, in the proper hands, could probably get it out real nice. You could also use a die grinder and a cutting wheel and cut the welds off.
Re: Is it bad to remove a set of weld-in SFCs? If you don't grind them off carefully, you may reallt tear up the subframes and you may do much more harm than good. I'm not sure that you will be able to justify the amount of work involved to do that swap. I also think that you will see little or no difference in performance between the two. If you are on a quest for ground clearance, it may be worth it, but I think you will wish you hadn't started that project about 1/2 way through it. I may be wrong...
Just my thoughts.
Just my thoughts.
Staging Lane
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From: Mason, OH
Re: Is it bad to remove a set of weld-in SFCs?
If you don't grind them off carefully, you may reallt tear up the subframes and you may do much more harm than good. I'm not sure that you will be able to justify the amount of work involved to do that swap. I also think that you will see little or no difference in performance between the two. If you are on a quest for ground clearance, it may be worth it, but I think you will wish you hadn't started that project about 1/2 way through it. I may be wrong...
Just my thoughts.
Just my thoughts.
Get them for your next car.
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Re: Is it bad to remove a set of weld-in SFCs? Im changing out SFCs for clearance, strength, and weight issues. If I was to guess, the SFCs on my car weigh about 25 lbs. each. Not only that, they hang down pretty low. I really want to remove and replace them. The reason this whole question came about, is because I heard when you cut, grind, etc. on the frame, it will cause damage to it. Im not worried at all about the SFCs, Im just worried about screwing up the body. I know that theres some work involved, but Ive got nothing better to do and I think that after its all said and done, I will be very pleased and releived. Thanks
Re: Is it bad to remove a set of weld-in SFCs?
Ive got nothing better to do
If you are really worried about 15 lbs (or whatever the difference is in the connectors), diet. Remember my friends.....Salad=Speed, eat light, go fast.....
As for removing the connectors, many modern vehicles are made out of high strength steel and don't do well after being heated (it changes the properties of the materials), I'd think they would do "less well" after being heated twice....
If you really want to go through with this, weld a chunk of steel to a piece of sheet metal (similar to your connectors and subframes) and start cutting, see how well it comes apart, multiply that by 50 or so and that is what it will take to get them off of there. It is not impossible, but I think we are "splitting hairs" when it comes to differences and possible improvements. But, ultimately, it is your project and decision. If you decide to proceed, I wish you the best of luck.
Just my thoughts....
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Re: Is it bad to remove a set of weld-in SFCs? I know that one of the keys to having good track numbers is your weight. Weight is a big factor in racing. There is going to be about a 40 lb. difference in weight in changing SFCs. Plus I will be using tubulars this time and there will be a big improvement in clearance. My SFCs hang lower than any other SFCs around! 
Im going to use a torch to cut them off or if I can get my hands on a plasma cutter, then I will use that.
Are you referring to the body/frame or the SFCs? If youre talking about the SFCs, then I dont care because theyre going to be scrap when theyre off. Im just worried about damaging/weakening the body/frame. Thanks
Im going to use a torch to cut them off or if I can get my hands on a plasma cutter, then I will use that.
As for removing the connectors, many modern vehicles are made out of high strength steel and don't do well after being heated (it changes the properties of the materials), I'd think they would do "less well" after being heated twice.
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Re: Is it bad to remove a set of weld-in SFCs? The body/frame....
I have an idea....go to the strip and make 2 or 3 passes then make 2 or 3 with a friend in the car (if your drag strip allows it), or put a 50 lb bag of sand in the trunk....see what your time difference actually is....then, decide if it is worth all that work and possible vehicle damage to save that amount (if you see any difference at all).
Just my thoughts.
I have an idea....go to the strip and make 2 or 3 passes then make 2 or 3 with a friend in the car (if your drag strip allows it), or put a 50 lb bag of sand in the trunk....see what your time difference actually is....then, decide if it is worth all that work and possible vehicle damage to save that amount (if you see any difference at all).
Just my thoughts.
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Verdad Gallardo Re: Is it bad to remove a set of weld-in SFCs? You said....
and then you said....
If my math is right, you are replacing 50 lbs of SFC's with 10 lbs of SFC's. If they are that light, I'd just skip them all together.... I think you will waste more hp twisting up the chassis (any hp that is twisting the body, is not making you go forward) than you will save on weight....
I could be wrong...
Just the world as I see it....
the SFCs on my car weigh about 25 lbs. each.
There is going to be about a 40 lb. difference in weight in changing SFCs
I could be wrong...
Just the world as I see it....
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Re: Is it bad to remove a set of weld-in SFCs? All those numbers I just threw out there. I dont know exactly how much the ones that I have on there now, but I know for sure that the ones that I plan to use are a bit over 13 lbs. together. The reason theyre so light is because theyre constructed of chromoly tubing. I just said that there was a 40 lb. difference because the ones that I have one there now probably weigh more than 25 lbs. each. So say they were 30 lbs each and you subtracted 13 lbs. (the weight of the new SFCs together) then it would come out to be 47 lbs. I just said 40 lbs. because that was an estimate. To be honest I have no idea how much mine weigh, but I know its up there. I know that there is going to be a big difference in weight and that the new SFCs are going to be just as strong if not stronger. I dont mind the work and from what everyone is telling me, its going to be a job and a big pain in the butt. But I dont mind all of that, Im just worried about screwing up the body/frame? If you say that it changed the properties of the material on the SFCs, then I would assume that it would do the same for the frame/body. Is it possible that I could damage, warp, or weaken the body/frame? This is a one time thing, the old ones are coming off and new ones are going on. Im going to try and use a plasma cutter, but if I cant get my hands on one, then I guess its a torch and a lot of grinding.
Re: Is it bad to remove a set of weld-in SFCs? The frame is possibly the high strength alloy, the connectors are typically mild steel. The mild steel won't have a problem with the heat, but some alloys will.
I'd still try the "bag of sand in the trunk" option to see how much your times change....I doubt it proves to be worth it....but I may be wrong.
I'm also concerned with damage to the subframes from "grinding them thin" in spots and similar problems. Grinding marks are a great place for stress risers...and stress risers are a great place for cracks to form. There is a potential for cracked subframes after grinding on them and then bracing them (in a slightly different location) with new connectors. This may cause stress concentrations in the area that the grinding has occured and that may (potentially) lead to cracking problems (which, if severe enough may leave you with a $27,000 paper weight in the driveway). However, you will never know for sure until you are done. It appears that you are "on a mission" and if you are really that concerned about it, then (as I said before) I wish you the best of luck. Let us know what happens.
As a side note, a plasma cutter will likley cut right through the subframes and connectors. I would try to minimize any cutting of the subframes. You can always weld it back up, but it may not be quite "the same" as it was.
I'd still try the "bag of sand in the trunk" option to see how much your times change....I doubt it proves to be worth it....but I may be wrong.
I'm also concerned with damage to the subframes from "grinding them thin" in spots and similar problems. Grinding marks are a great place for stress risers...and stress risers are a great place for cracks to form. There is a potential for cracked subframes after grinding on them and then bracing them (in a slightly different location) with new connectors. This may cause stress concentrations in the area that the grinding has occured and that may (potentially) lead to cracking problems (which, if severe enough may leave you with a $27,000 paper weight in the driveway). However, you will never know for sure until you are done. It appears that you are "on a mission" and if you are really that concerned about it, then (as I said before) I wish you the best of luck. Let us know what happens.
As a side note, a plasma cutter will likley cut right through the subframes and connectors. I would try to minimize any cutting of the subframes. You can always weld it back up, but it may not be quite "the same" as it was.
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Re: Is it bad to remove a set of weld-in SFCs? What would be the safest way to remove welded SFCs? Youve got me really scared now! I dont want to ruin my frame/body. If it takes hours and hours to take them off, but avoids me from messing something up, then Im ok with that. Id like to get them off as quick as I can, but if by doing that causes me to heat up the frame/body too much and causing them to weaken and possibly crack later, then I dont want to do that. There is going to be a big weight and clearance difference, but thats not why Im doing this. Im doing it because I hate the SFCs that I have on there now and I wanted to replace them with a nice set so that it matches the rest of my suspension. I know youre thinking, "oh my gosh, just so that it matches"...no not just that, theres several reasons, but Im not going into detail with it. Anyhow, if I cut the SFCs out without cutting into the body/frame, then will I be ok? Im going to try and cut them out as neat as I can, but if you tell me that cutting them out with a plasma cutter or a torch isnt the safest way, then I wont do so, but I will need another option. Gosh Trackbird, I knew that I had some concern on my hands by removing these SFCs, but now you just pointed out something that I should really take into consideration. I really appreciate you telling me what I might be in risk of. If it was you, and you were bound to take these SFCs out, how exactly would you do it? Thanks
I dont want to ruin my frame/body. If it takes hours and hours to take them off, but avoids me from messing something up, then Im ok with that. Id like to get them off as quick as I can, but if by doing that causes me to heat up the frame/body too much and causing them to weaken and possibly crack later, then I dont want to do that. There is going to be a big weight and clearance difference, but thats not why Im doing this. Im doing it because I hate the SFCs that I have on there now and I wanted to replace them with a nice set so that it matches the rest of my suspension. I know youre thinking, "oh my gosh, just so that it matches"...no not just that, theres several reasons, but Im not going into detail with it. Anyhow, if I cut the SFCs out without cutting into the body/frame, then will I be ok? Im going to try and cut them out as neat as I can, but if you tell me that cutting them out with a plasma cutter or a torch isnt the safest way, then I wont do so, but I will need another option. Gosh Trackbird, I knew that I had some concern on my hands by removing these SFCs, but now you just pointed out something that I should really take into consideration. I really appreciate you telling me what I might be in risk of. If it was you, and you were bound to take these SFCs out, how exactly would you do it? Thanks 
Re: Is it bad to remove a set of weld-in SFCs?
What would be the safest way to remove welded SFCs? Youve got me really scared now! I dont want to ruin my frame/body. If it takes hours and hours to take them off, but avoids me from messing something up, then Im ok with that. Id like to get them off as quick as I can, but if by doing that causes me to heat up the frame/body too much and causing them to weaken and possibly crack later, then I dont want to do that. There is going to be a big weight and clearance difference, but thats not why Im doing this. Im doing it because I hate the SFCs that I have on there now and I wanted to replace them with a nice set so that it matches the rest of my suspension. I know youre thinking, "oh my gosh, just so that it matches"...no not just that, theres several reasons, but Im not going into detail with it. Anyhow, if I cut the SFCs out without cutting into the body/frame, then will I be ok? Im going to try and cut them out as neat as I can, but if you tell me that cutting them out with a plasma cutter or a torch isnt the safest way, then I wont do so, but I will need another option. Gosh Trackbird, I knew that I had some concern on my hands by removing these SFCs, but now you just pointed out something that I should really take into consideration. I really appreciate you telling me what I might be in risk of. If it was you, and you were bound to take these SFCs out, how exactly would you do it? Thanks
I dont want to ruin my frame/body. If it takes hours and hours to take them off, but avoids me from messing something up, then Im ok with that. Id like to get them off as quick as I can, but if by doing that causes me to heat up the frame/body too much and causing them to weaken and possibly crack later, then I dont want to do that. There is going to be a big weight and clearance difference, but thats not why Im doing this. Im doing it because I hate the SFCs that I have on there now and I wanted to replace them with a nice set so that it matches the rest of my suspension. I know youre thinking, "oh my gosh, just so that it matches"...no not just that, theres several reasons, but Im not going into detail with it. Anyhow, if I cut the SFCs out without cutting into the body/frame, then will I be ok? Im going to try and cut them out as neat as I can, but if you tell me that cutting them out with a plasma cutter or a torch isnt the safest way, then I wont do so, but I will need another option. Gosh Trackbird, I knew that I had some concern on my hands by removing these SFCs, but now you just pointed out something that I should really take into consideration. I really appreciate you telling me what I might be in risk of. If it was you, and you were bound to take these SFCs out, how exactly would you do it? Thanks 
Re: Is it bad to remove a set of weld-in SFCs?
If it was you, and you were bound to take these SFCs out, how exactly would you do it?
Just my thoughts.
Staging Lane
Joined: Apr 2002
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From: Bay Area, CA
Re: Is it bad to remove a set of weld-in SFCs? I think it can be pretty easy or very difficult depending upon the set of SFCs installed and how you plan on removing them. I'm removing KBDDs and installing SLPs instead. First off, I'm taking my car to a top notch shop that does lots of high end chassis work, along with charging $90/hour, so they'd better do a good job. Anyways, I plan to just cut off the 1"x1" bar from the front subframe attachment points, leaving the plate attached to the subframe. Shouldn't cause the SLPs to sit much higher. The pinch weld attachments can be easily removed. The rear isn't welded to the control arm, just bolted. The other rearward portion will remain, but the 1x1 arm will be cut to attach to the SLP 1x1 rearward arm.
I prefer die-grinding rather than any method which heats up the SFC welds significantly. Repeated thermal cycles can do undesirable things to an alloy.
Last, if a mistake is made and a portion of the frame is thinned to much or cut into, they can always weld in a patch. This can leave the "damaged" area stronger than it was stock.
I prefer die-grinding rather than any method which heats up the SFC welds significantly. Repeated thermal cycles can do undesirable things to an alloy.
Last, if a mistake is made and a portion of the frame is thinned to much or cut into, they can always weld in a patch. This can leave the "damaged" area stronger than it was stock.