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Here's what I'm gonna be working with, and IRS setup in my car exactly like this pic:What I plan to do, with the assistance of people who have done this before with mild steel, is add chromoly tubing in areas that could use reinforcement (in the IRS and to the car unibody). Others have used regular mild steel, but I decided that if I'm gonna add weight, it better be the strongest it can [reasonably] be.I've read through all the threads about TIG welding chromoly steel. I have found that ER70-S2 is recommended when not PWHT'ing the parts (which I won't be). My only reservation is this: mostly all (if not all) of those threads were discussing roll bars/cages for race car fabrication, where the added ductility of ER70-S2 is a benefit. I will be using the chromoly steel for reduction of IRS deflection/chassis flex reduction.In my mind, I'm seeing as ER80S-D2 as being a better choice due to it's lower ductility and resemble chromoly's strength best (as per Lincoln Website), seeing as how I do not want these added braces to flex in the least bit.Am I thinking straight? Or do I need some sense slapped into me? Last edited by Oscar; 12-23-2012 at 02:43 AM.
Reply:I agree, Er80s-d2 is a superior filler for tig IMO. I use it quite often and it flows nicer too. I have several jobs that specify ER80 filler on 4130 prehardened structures with 200 degree F., no post weld stress relief.Weld like a "WELDOR", not a wel-"DERR" MillerDynasty700DX,Dynasty350DX4ea,Dynasty200DX,Li ncolnSW200-2ea.,MillerMatic350P,MillerMatic200w/spoolgun,MKCobraMig260,Lincoln SP-170T,PlasmaCam/Hypertherm1250,HFProTig2ea,MigMax1ea.
Reply:I think you need to think a bit about what kind of loads your reenforcements are supposed to handle. Chrome moly may be a very strong choice in a structure where the specific strengths of CM is needed, but another structure under diffrent loads and possibly non-optimal welding processes may become weaker than common mild steel. Using a high strength material does NOT automatically make a better product.
Reply:You kind of answered your own question a bit. You don't want filler that's the same characteristics of the 4130 base, because without post heat treat, there is a strong likelihood of brittleness and cracking. You WANT a certain amount of flex. No flex = break/crack. Are you concerned the ER70 won't be strong enough? Yes, ER80 will most likely work, but the rigidity it adds only in the joint will probably be unnoticeable. Most of the flex and bend you get will be in the length of the bars, which won't really change with the filler you use, rather the way you structure everything.
Reply:Keep in mind that the chromoly steels are STRONGER than low carbon steels but they are not stiffer, section for section. The modulus of elasticity for all steels is virtually the same. Ultimate strength and yield strengths differ with alloy but not the stiffness.In a suspension, you're after stiffness. You want to minimize deflections in steer and camber from the road inputs. If the suspension module is from a reputable manufacturer, those structural stiffness are likely to be optimized by the original design. If you want stiffness, look at bushing hardness.
Reply:Thanks for the replies guys. Originally Posted by ZmechanicAre you concerned the ER70 won't be strong enough? Yes, ER80 will most likely work, but the rigidity it adds only in the joint will probably be unnoticeable. Most of the flex and bend you get will be in the length of the bars, which won't really change with the filler you use, rather the way you structure everything.
Reply:Why do you want irs for drag racing? I know a guy running low 8's with an 8.8.tackleexperts.comwww.necessityjigs.comhttps://www.facebook.com/groups/mach...dingequipment/
Reply:Originally Posted by brucerWhy do you want irs for drag racing? I know a guy running low 8's with an 8.8.
Reply:Originally Posted by OscarWhere did it say that I wanted it? This IRS has an 8.8---I don't get your point here.
Reply:Originally Posted by johokesslYou want to minimize deflections in steer and camber from the road inputs
Reply:I would use er70s-2 being the crossmember and related suspension components are going to be a low quality steel... even if you decide to use chromoly, I would still use er70s-2, I would also cover the welds with a fireblanket to help slow cooling. Really no need to use chromoly unless you just want to spend more money and more time. unless your planning to put a lot of mass in the car, such as a cage, sub-frame connectors, front k-member and a-arms at that point you'll see good weight savings going with chromoly.. plus I dont think a little weight over the rear is going to hurt you much.. Actually I would be more worried about the half shafts breaking than anything else.. http://www.aws.org/wj/apr03/AWfeature.html last paragraph pretty much sums it up.. heres another good read explaining http://www.netwelding.com/Welding%204130.htmyou running a ford, dodge or chevy?Last edited by brucer; 12-24-2012 at 06:35 AM.tackleexperts.comwww.necessityjigs.comhttps://www.facebook.com/groups/mach...dingequipment/
Reply:If you plan to push any real power at a drag strip you are going to hate the IRS setup.If you are talking about bracing to the car chassis I would NOT use 4130. Chromoly should be secluded to itself and not welded to car sheet metal.If you think you have enough know how to brace up an IRS for drag racing you should be able to swap in a strait axle.
Reply:Originally Posted by VPTIf you plan to push any real power at a drag strip you are going to hate the IRS setup.If you are talking about bracing to the car chassis I would NOT use 4130. Chromoly should be secluded to itself and not welded to car sheet metal.If you think you have enough know how to brace up an IRS for drag racing you should be able to swap in a strait axle.
Reply:Originally Posted by VPTIf you think you have enough know how to brace up an IRS for drag racing you should be able to swap in a strait axle.
Reply:Since you are using it for drag racing, first and foremost, check the rules of your sanctioning body even for filler type. It's not so much that they'd be able to tell once you did it (like the rule where they specify you have to use the same lot code for a cage), but it's a good idea to follow it. I would have said that before, but figured it was just a swap for a hot rod or something.
Reply:Originally Posted by OscarAll Isn't that what all race cars are---just spending money? LOL. I mean really who needs a racecar to "be". It's all about spending money to have fun racing!
Reply:Originally Posted by ZmechanicSince you are using it for drag racing, first and foremost, check the rules of your sanctioning body even for filler type. It's not so much that they'd be able to tell once you did it (like the rule where they specify you have to use the same lot code for a cage), but it's a good idea to follow it. I would have said that before, but figured it was just a swap for a hot rod or something.
Reply:It just doesn't compute. Its the same as hearing a road race guy talking about swapping a strait axle into his corvette.
Reply:why doesn't it compute? Perhaps your algorithm/logic isn't up to par.Several people, not just one, have successfully utilized the IRS their car came with, with hundreds more horsepower than I will be making. Their cars are quicker than mine will ever be. You do know the meaning of the word "successfully", right?? Where did I say I have the know-how to decide where to properly add bracing to the IRS? I clearly stated at the very beginning of this thread, this project will be done with the advice and guidance of people who have already walked this path and have already tried many, many bracing schemes with this exact setup. They are the ones who have likely invested hundreds of man hours into trying different bracing, trying it out on the drag strip, and changing/deleting/modifying the bracing into something that DOES work. I an not claiming, nor did I ever claim, to be some kind of expert race car chassis fabricator----hence one of the very first lines in the very first post when I created this thread: Originally Posted by OscarWhat I plan to do, with the assistance of people who have done this before.....
Reply:oscar, just curious what are you working on? I traded my 80 big block chevy truck that I tubbed put a 9inch in it and 6pt cage for a 98 trans-am with 88k miles on it and a spare 6.0 engine and a 2004 honda 350 4 wheeler that had 160hrs on it.. cant make up my mind if i want to build the TA as a cruiser and keep it or just sell the TA and put that money into my 27ford..tackleexperts.comwww.necessityjigs.comhttps://www.facebook.com/groups/mach...dingequipment/
Reply:Originally Posted by bruceroscar, just curious what are you working on? I traded my 80 big block chevy truck that I tubbed put a 9inch in it and 6pt cage for a 98 trans-am with 88k miles on it and a spare 6.0 engine and a 2004 honda 350 4 wheeler that had 160hrs on it.. cant make up my mind if i want to build the TA as a cruiser and keep it or just sell the TA and put that money into my 27ford..
Reply:sounds like your going to have a small fortune in it..tackleexperts.comwww.necessityjigs.comhttps://www.facebook.com/groups/mach...dingequipment/
Reply:Originally Posted by brucersounds like you have a small fortune in it..
Reply:Originally Posted by VPTIf you are talking about bracing to the car chassis I would NOT use 4130. Chromoly should be secluded to itself and not welded to car sheet metal.
Reply:Oscar a lot of posters offer info with all the right intentions and perhaps don't have a lot of experience in the use of 4130.We use 4130 all the time, (sprintcar chassis' and a whole lot more) and often we find customers that have gained a little bit of knowledge but sometimes what they think of the material is incorrect.The main reason that customers "should" be thinking of 4130 is if they are looking at building light racing structures.If using tubing that is similar size for size comparing 4130 to DOM CDW tubing and the CDW is adequate for the task then use the CDW simply to save money.If however you're looking at reducing tube sizes or wall thicknesses to save weight then go down the 4130 route.Don't be frightened of using 4130 it's simply a high quality steel tubing and it's really nice to weld as well.For us, and indeed most of the Sprintcar manufacturers, heat treating is a non issue and basically across the board no heat treating either pre or post is done.The only exception to this is on heavy structures, but as a rule all the chassis are welded with no heat treating.For us we use ER70S2 filler but if I need smaller wire than the usual 1.6mm and 2.4mm we have in stock I'll use cut down LW1 Mig wire which is ER70S6 with equally good results.Remember, 4130 can also be Mig welded if required with no problems.Regards Andrew from Oz.Originally Posted by OscarGranted, when roll cages are welded to cars' chassis, they use thick flat plate, but eventually you have to weld mild steel [plate] to chromoly [tubing]--how else are roll cages installed in production vehicles?
Reply:Originally Posted by awill4x4Oscar a lot of posters offer info with all the right intentions and perhaps don't have a lot of experience in the use of 4130.We use 4130 all the time, (sprintcar chassis' and a whole lot more) and often we find customers that have gained a little bit of knowledge but sometimes what they think of the material is incorrect.The main reason that customers "should" be thinking of 4130 is if they are looking at building light racing structures.If using tubing that is similar size for size comparing 4130 to DOM CDW tubing and the CDW is adequate for the task then use the CDW simply to save money.If however you're looking at reducing tube sizes or wall thicknesses to save weight then go down the 4130 route.Don't be frightened of using 4130 it's simply a high quality steel tubing and it's really nice to weld as well.For us, and indeed most of the Sprintcar manufacturers, heat treating is a non issue and basically across the board no heat treating either pre or post is done.The only exception to this is on heavy structures, but as a rule all the chassis are welded with no heat treating.For us we use ER70S2 filler but if I need smaller wire than the usual 1.6mm and 2.4mm we have in stock I'll use cut down LW1 Mig wire which is ER70S6 with equally good results.Remember, 4130 can also be Mig welded if required with no problems.Regards Andrew from Oz.
Reply:Originally Posted by VPTIt just doesn't compute. Its the same as hearing a road race guy talking about swapping a strait axle into his corvette.
Reply:Originally Posted by OscarWith bit more searching, found this:from: http://weldingweb.com/vbb/showthread.php?t=26897also, http://weldingweb.com/vbb/showthread.php?t=4102http://www.millerwelds.com/resources...el-to-chromolyhttp://www.weldingtipsandtricks.com/...-chromoly.htmlhttp://forum.weldingtipsandtricks.co....php?f=5&t=742http://www.millerwelds.com/resources...el-to-chromolyEverything I have found searching leads me to believe that mild steel can be welded to chromoly.Granted, when roll cages are welded to cars' chassis, they use thick flat plate, but eventually you have to weld mild steel [plate] to chromoly [tubing]--how else are roll cages installed in production vehicles?
Reply:Originally Posted by VPTI wasn't saying it can't be welded together. I was saying the joint will just be the weak spot.Not long ago I welded aluminum to stainless as well. The weld looked great!Just because two metals can be welded together doesn't mean the joint will be as strong as either of the two metals.Good luck with your adventure.
Reply:Originally Posted by VPTI wasn't saying it can't be welded together. I was saying the joint will just be the weak spot.Not long ago I welded aluminum to stainless as well. The weld looked great!Just because two metals can be welded together doesn't mean the joint will be as strong as either of the two metals.Good luck with your adventure.
Reply:Originally Posted by brucermoonshine still?
Reply:I think you will find that 4130 material will be more cost effective when it come time to buy it vs DOM. I've done a lot of car building, chassis building and suspension stuff for drag racing from bone stock cars to TOP Fuel Funny Cars over the yeaqrs. The racing organizations require 4130 and inspect welds and structures.It is a nice material to fab and weld. Maybe a little hard on saw blades if you push feeds and speeds. It is very clean to begin with and easy to prep..Joint design and prep for deep pen welds will be very important. You must also look -at not overheating the welds by going too slow and not using enough weld power. Your part design and welds will be far more important than diddling around with various fillers and material. Just use 4130 and er70-s2. It is well proven....no need to re-invent.er70-s2 is the recommended filler. We used to use er70-s6 but there is no real difference, I think the rod purity is a little better but I haven't seen and proof it is better.Last edited by bentwings; 12-29-2012 at 12:48 AM.
Reply:Originally Posted by bentwingsI think you will find that 4130 material will be more cost effective when it come time to buy it vs DOM. I've done a lot of car building, chassis building and suspension stuff for drag racing from bone stock cars to TOP Fuel Funny Cars over the yeaqrs. The racing organizations require 4130 and inspect welds and structures.
Reply:Originally Posted by Mario428Beleive this thread is not about a roll cage but bracing an IRS so use whatever you want. The IRS looks like a T-Bird to me.IMHO the small amount of tubing required to do what the OP wants to do the weight difference of the tubing will be meaningless. I would get some .120 wall ERW and have at it, easy to find and more than strong enough.
Reply:I happen to own an '03 Cobra (convertible). So I know all about flex.I would highly recommend that you look at http://fulltiltboogieracing.com/irs.htm for bushings. Read his tech articles.You can also consider:http://www.maximummotorsports.com/st...ath=514_88_191I haven't heard of anyone actually bracing the IRS cradle. Not sure its necessary. There is plenty of flex in the body itself.As for the chassis itself.I highly recommend Global West's subframe connectors. They fit pretty tight under the car - just move the fuel and brake lines a bit. For a couple pieces of steel they are a bit pricey IMHO. But I guess you are paying for engineering time to get the bends in the right place. First time I installed, I suspect I had 8 hours in it. Lots of little tubes to cut and weld and lots of double checking before you weld it home.The Global West SFCs will add so much stiffness to the car, the first time I test drove it, I had to check twice if I left a floor jack or jackstand under the car. yes, just getting into the car (first time I had a '90 LX) I noticed the difference. Absolutely amazing difference in feel when you drive. I put GW's SFCs in every fox body mustang I've owned or my friends have owned.If you don't mind stripping the interior - look at the Grigg's kit. Way over priced for what you get, but it works and again, you are paying for engineering. Its a 'through the floor subframe kit' As for mild steel vs. CM. Unless you are putting your car on a serious diet, you will not see any benefit from making a brace out of CM. IMHO, any racecar that is 3500+lbs is a fat pig. If you have plan to get to, say 2800lbs, then lets talk.I stuck with IRS for two reasons. I hate the axle 'hop' that mustangs are famous for during any kind of upset in a turn and for a multipurpose car, the ride is much better.However, for maximum performance in a drag racing only situation, your giving up traction with an IRS. As the rear suspension moves, the camber angles of the rear wheels change - that means your contact patch isn't perfectly flat.For a drag race only car I would bite the bullet and get a Ford 9".The big problem is that all out drag cars make lousy.... even unsafe street cars. Shocks too weak, springs too light, sway bars all wrong etc. etc. The IRS is workable, and makes it a better dual purpose car. Not to mention the extra weight on the back balances the car a bit better.Con Fuse!Miller Dynasty 350Millermatic 350P-Spoolmatic 30AMiller Multimatic 200Hypertherm PowerMax 1000G3Miller Maxstar 200DX
Reply:Originally Posted by bentwingsI think you will find that 4130 material will be more cost effective when it come time to buy it vs DOM.
Reply:Originally Posted by con_fuse9I happen to own an '03 Cobra (convertible). So I know all about flex.I would highly recommend that you look at http://fulltiltboogieracing.com/irs.htm for bushings. Read his tech articles.You can also consider:http://www.maximummotorsports.com/st...ath=514_88_191I haven't heard of anyone actually bracing the IRS cradle. Not sure its necessary. There is plenty of flex in the body itself.As for the chassis itself.I highly recommend Global West's subframe connectors. They fit pretty tight under the car - just move the fuel and brake lines a bit. For a couple pieces of steel they are a bit pricey IMHO. But I guess you are paying for engineering time to get the bends in the right place. First time I installed, I suspect I had 8 hours in it. Lots of little tubes to cut and weld and lots of double checking before you weld it home.The Global West SFCs will add so much stiffness to the car, the first time I test drove it, I had to check twice if I left a floor jack or jackstand under the car. yes, just getting into the car (first time I had a '90 LX) I noticed the difference. Absolutely amazing difference in feel when you drive. I put GW's SFCs in every fox body mustang I've owned or my friends have owned.If you don't mind stripping the interior - look at the Grigg's kit. Way over priced for what you get, but it works and again, you are paying for engineering. Its a 'through the floor subframe kit' As for mild steel vs. CM. Unless you are putting your car on a serious diet, you will not see any benefit from making a brace out of CM. IMHO, any racecar that is 3500+lbs is a fat pig. If you have plan to get to, say 2800lbs, then lets talk.I stuck with IRS for two reasons. I hate the axle 'hop' that mustangs are famous for during any kind of upset in a turn and for a multipurpose car, the ride is much better.However, for maximum performance in a drag racing only situation, your giving up traction with an IRS. As the rear suspension moves, the camber angles of the rear wheels change - that means your contact patch isn't perfectly flat.For a drag race only car I would bite the bullet and get a Ford 9".The big problem is that all out drag cars make lousy.... even unsafe street cars. Shocks too weak, springs too light, sway bars all wrong etc. etc. The IRS is workable, and makes it a better dual purpose car. Not to mention the extra weight on the back balances the car a bit better.
Reply:I feel like I am in high school again in this thread.Just because there isn't a "kit" for putting some part in a car doesn't mean it is an impossible feat. Honestly if you are keeping the IRS and aren't shooting for sub 10's I for sure wouldn't go with the 4130 and all the problems that can come with it if you aren't good with welding. The 20 pounds you'll save you would never notice, ever. But you will notice cracks at the 4130 to mild joints after a year of racing.This 8 second car got all mild steel and a strait axle. Yup, even runs on half leafs.The old junk before we cut the rear end up.
Reply:I never said it was impossible to do a solid axle. I only said it won't be an easy feat for me to create such a swap--therefore the only other option would be to purchase a swap kit, yet none exists, thereby eliminating the only other "option". ...and great if you wouldn't do this or that. Not looking for opinions on what you would or would not do with my car. But feel free to keep posting even though my initial query has already been answered. Absolutely NO ONE is asking you to "stay in high school" in this thread, so why bother?Last edited by Oscar; 12-30-2012 at 02:30 PM.
Reply:Weld it all up, I'm sure it will be just fine. Don't forget pics!
Reply:I personally would put a 8.8in it. get one from an explorer?? have it cut to length, build a sub frame from DOM and use FOX type suspension pieces. no different then doing a back-half caror you could to go here.....http://www.yellowbullet.com/forum/but be careful, they are brutal in thereand go to the NOOB thread 1st!!!! or they will eat you alive were you're standing |
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发表于 2021-8-31 22:58:56