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Invincibleextremes

Ford Super 8.8 irs swap thread. Rear brakes too

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I'll likely MIG my 4130 with preheat as much as possible, back purge or flux the off side and post treat to minimize heat effected zones. The old traditional aircraft 4130 is welded with a torch which just by the way it works is a much gentler heat and pretty much gives you that post treat if let to cool slowly. I have a 350P MIG and a 200DX TIG so can go either way, yes I have a torch too but I'll reserve that for pre-heat. Most are not going to want to go to that trouble and expense and will be better off with a well designed mild steel part. Cold rolled is cleaner and more consistent in plate/sheet.

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Posted (edited)

Regular mild has been great for the brake brackets that I've been building, so I'm seriously leaning towards that.  And there's less chance of making it brittle, which is something I want to avoid at all costs.

 

Uncle Sam has me pretty much booked till July, so I'm a few thousand miles away doing my thing.  Brainstorming in the mean time but can't physically cut and fit anything.  At least my driveshaft adapter and 315 rear tires are there, so I'll be able to do some vigorous durability testing once I bolt it all in.

Edited by Invincibleextremes
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All good points there JPNDave. 4130 requires a welding process that is better controlled than what mild steels require, the payoff is that you can use less material and achieve a tougher, stronger and longer lasting part that can be made with less material. The less material benefit is something that should be seriously considered for this type of part, especially if the joints are going to be MiG welded. Using less material will allow you to consistently hit your penetration depth easier which could make it alot easier for most people to perform the finished welds on these parts.

 

While it is recommended to preheat 4130 and post stress relieve it, we have not seen these practices as required when using conventional welding machines. These practices may be required depending on how the 4130 was formed or if it is being welded post heat treatment or in a pre-hard state. My company has never encountered stress cracking or embrittlement issues when welding 4130 in it's annealed state using conventional welding techniques. The carbon content is not quite high enough to necessitate the heat treatment post weld. 4140 and up is when we have started seeing the need for the pre and post heat.

 

Any machine shop worth their salt isnt going to have an issue machining 4130. Mild steel can certainly be machined at higher feed rates, but 4130 is by no means difficult to machine.

 

I had assumed the cost would be higher for 4130 as well but I looked at a few local suppliers and the prices were not much higher than 1018. That will likely change based on your location and supplier though.

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5 hours ago, ISPKI said:

All good points there JPNDave. 4130 requires a welding process that is better controlled than what mild steels require, the payoff is that you can use less material and achieve a tougher, stronger and longer lasting part that can be made with less material. The less material benefit is something that should be seriously considered for this type of part, especially if the joints are going to be MiG welded. Using less material will allow you to consistently hit your penetration depth easier which could make it alot easier for most people to perform the finished welds on these parts.

 

While it is recommended to preheat 4130 and post stress relieve it, we have not seen these practices as required when using conventional welding machines. These practices may be required depending on how the 4130 was formed or if it is being welded post heat treatment or in a pre-hard state. My company has never encountered stress cracking or embrittlement issues when welding 4130 in it's annealed state using conventional welding techniques. The carbon content is not quite high enough to necessitate the heat treatment post weld. 4140 and up is when we have started seeing the need for the pre and post heat.

 

Any machine shop worth their salt isnt going to have an issue machining 4130. Mild steel can certainly be machined at higher feed rates, but 4130 is by no means difficult to machine.

 

I had assumed the cost would be higher for 4130 as well but I looked at a few local suppliers and the prices were not much higher than 1018. That will likely change based on your location and supplier though.

Definately glad you guys are pitching in with ideas.

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13 hours ago, ISPKI said:

All good points there JPNDave. 4130 requires a welding process that is better controlled than what mild steels require, the payoff is that you can use less material and achieve a tougher, stronger and longer lasting part that can be made with less material. The less material benefit is something that should be seriously considered for this type of part, especially if the joints are going to be MiG welded. Using less material will allow you to consistently hit your penetration depth easier which could make it alot easier for most people to perform the finished welds on these parts.

 

While it is recommended to preheat 4130 and post stress relieve it, we have not seen these practices as required when using conventional welding machines. These practices may be required depending on how the 4130 was formed or if it is being welded post heat treatment or in a pre-hard state. My company has never encountered stress cracking or embrittlement issues when welding 4130 in it's annealed state using conventional welding techniques. The carbon content is not quite high enough to necessitate the heat treatment post weld. 4140 and up is when we have started seeing the need for the pre and post heat.

 

Any machine shop worth their salt isnt going to have an issue machining 4130. Mild steel can certainly be machined at higher feed rates, but 4130 is by no means difficult to machine.

 

I had assumed the cost would be higher for 4130 as well but I looked at a few local suppliers and the prices were not much higher than 1018. That will likely change based on your location and supplier though.

I really had to look fairly hard  to get annealed tubing in 3" od for a motorcycle project. Most everything is in a "normalized" condition. Not really heat treated to full potential and not annealed. That is what is typically used in race cars and aircraft. I'll dig up some specific numbers when I get a chance. If you can work the material annealed then heat treat the assembly fixtured to avoid distortion that would be ideal but in reality is simply not practical. 4130 is much more likely to stress crack (maybe not in the annealed state) than mild steel but definitely isn't really an exotic material. In the annealed condition is loses much of it's advantage over mild steel as the tensile strength just isn't up where it should be. There are racing organizations that require 4130 be left unpainted to allow it to be inspected for stress fractures. I'll find the numbers which will be much more telling than bantering on about things. Facts speak more clearly I my experience.

 

I agree thinner sections would be better for either material both from a weight saving and like you mentioned on being able to get full penetration welds. Most home shops don't have MIGs capably of punching through that heavy material and it shouldn't be necessary. The only place I would use those plate thicknesses is on my Backhoe and yes the 350P will penetrate it but that is a lot to punch through.

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Posted (edited)
13 hours ago, DeathByNissan55 said:

Now this is the level of discussion I like to see.

Glad you are enjoying it! 😉

I appreciate the members on this forum. There are some really knowledgeable people on here. If we can keep discussions civil discussions and share knowledge we're all better for it.

Edited by jpndave

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Posted (edited)

Here are pics of that 3" .095 tubing after being rolled and why I needed it in the annealed condition. I don't think the rollers would have handled "normalized" and likely would have at least partially crushed the tube.

 

Pardon the messy shop, should have the new one more orderly in a bit.

P1010466.thumb.JPG.694f296329ddb2615f39530889769384.JPGP1010470.thumb.JPG.d5e6381cad4f62f89da7022701f455be.JPG

Edited by jpndave

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Posted (edited)

So patience is not one of my best strengths. However my favorite reference Carroll Smith's "Engineer to Win" I loaned to JD (69Honda here) to read while he was gone to Green Beret training so these numbers are best I could come up with quickly and seem to fit with what I generally remember.

 

Mild Steel ~ 40-50K Yield and just under 60-70K ultimate unless quenched but it will get brittle

4130 Annealed ~ 50+K Yield and 80+K ultimate

4130 Normalized (cold drawn) 87K Yield and 98K Ultimate

4130 Mild heat treat ~130K yield and 145K Ultimate

 

I highly recommend Smith's full series but especially "Engineer to Win", "Tune to Win" is great for suspension and chassis dynamics.

 

For Reference, 4340 annealed is 108K and a maximum usable of close to 220K. 300M can go to 300K and not lose toughness. Those are different types of loads more suited to the axles and hubs not chassis parts in thin sections.

 

Look at this post here, most of which is pulled from Smith's book: http://www.pirate4x4.com/tech/billavista/PR-BV60/index1a.html Most of the cautions, proceedure, advice etc. are from Smith. Those books should be required reading when we get into this stuff IMO.

 

And another racing type post with good perspective again quoting Carroll Smith https://grassrootsmotorsports.com/forum/grm/chrome-moly-or-mild-steel/88293/page1/

 

HTH

 

Dave

Edited by jpndave

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5 hours ago, jpndave said:

 

Out of curiosity Dave, what type of "Mild Steel" are you referencing? I read a bit through those links you posted and they are talking about 1080 mild steel which last I checked is classified as a high carbon steel. Annealed 4130 would be superior in every way to a mild steel, albeit only marginally without a significant investment for heat treatment. The strength gains probably would not justify the added costs of even the base material since you could just beef up the mild steel slightly to meet the strength of the 4130.

 

The primary concern I have with trying to weld super thick MS is that the joints would need to have extremely deep bevels in order to achieve full penetration. 1in thick 1018 is strong and all, but it is useless if you cant achieve CJP which would require at least a .375" deep U joint (I would go even deeper if using a 110v MiG).

 

Regardless, the pirate 4x4 information is quite interesting. Especially the notes on stress and failure analysis. I happen to use the same program at my work to perform the same stress analysis for the various industries that my company does business in.

 

InvincibleExtremes: If you were so interested, I could probably create your designs in the software that I have and run a series of stress tests on it using a range of different materials. If that is something that you would like to pursue, then shoot me a PM and we can talk about it.

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Posted (edited)
5 hours ago, ISPKI said:

Out of curiosity Dave, what type of "Mild Steel" are you referencing? I read a bit through those links you posted and they are talking about 1080 mild steel which last I checked is classified as a high carbon steel. Annealed 4130 would be superior in every way to a mild steel, albeit only marginally without a significant investment for heat treatment. The strength gains probably would not justify the added costs of even the base material since you could just beef up the mild steel slightly to meet the strength of the 4130.

 

The primary concern I have with trying to weld super thick MS is that the joints would need to have extremely deep bevels in order to achieve full penetration. 1in thick 1018 is strong and all, but it is useless if you cant achieve CJP which would require at least a .375" deep U joint (I would go even deeper if using a 110v MiG).

 

Regardless, the pirate 4x4 information is quite interesting. Especially the notes on stress and failure analysis. I happen to use the same program at my work to perform the same stress analysis for the various industries that my company does business in.

 

InvincibleExtremes: If you were so interested, I could probably create your designs in the software that I have and run a series of stress tests on it using a range of different materials. If that is something that you would like to pursue, then shoot me a PM and we can talk about it.

I just posted up what was on the referenced site. The common 1018 you are referring to would be lower. I did find my copy of "Engineer to Win" so I'll grab some info from that. Most of what is on the links is pretty much plaigerised from Smith. In high performance applications he's pretty blunt and brutal on mild steel.

 

What you are posting here is basically the points I was trying to make. Your perspective here clarifies that a bit more. Without proper treatment annealed 4130 has minimal strength gains and major cost. With care and some minimal pre and post treatment it can easy go double the strength which allows thinner sections and lighter weight. However cost is higher, harder to get and care must be taken to avoid areas that would be prone to cracks/stress fractures. Filler metal either needs to be such that when blended with the parent metal is more malleable and thus reduces brittle tendencies or maybe takes a mild treatment. Thicker sections at the weld make up for lost tensile strength. 4130 filler should NEVER be used unless the full completed part goes through a full heat treat. I've debated between ER70 and ER80 and have seen both recommended, leaning towards the 80. Most of that is out of bounds for a shade tree guy with budget mig. I'm sure you have the skills and equipment to get it right.

 

To pull back on topic a bit, the targeted sales for most of these kits would be better served in mild steel with a bit thinner sections for weight and weld penetration.

 

Using 4130 instead as an option in thinner sections would be ok with serious warnings and maybe liability waiver for advanced users but probably not worth the effort using these designs as if you are going to go to that much trouble, you're likely full on replacing everything not piecing stuff together to get a great "bang for the buck" universal solution like is set up here. It's fun to have advanced conversations about more exotic materials (yes I know 4130 is pretty mainstream in performance circles) but we are probably derailing this thread from its intended audience.

 

Your stress analysis would likely lead to a major redesign, half the weight in mild steel and a stronger part with less material and cost before even touching 4130. I'll reference back to my post on Jun 5th #3 item on ways to gain strength. #1 mass, #2 stronger materials (4130) # 3 better design.

 

Sorry if I'm posting too much on your thread Invincibleextremes. Don't mean to step on toes.

 

HTH

Edited by jpndave

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The whole purpose of this swap is to do something cheap and readily available. If you use a material that requires heat treating and a specialty welder, you alienate almost the entire target market. 

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32 minutes ago, calZ said:

The whole purpose of this swap is to do something cheap and readily available. If you use a material that requires heat treating and a specialty welder, you alienate almost the entire target market. 

 

4130 doesnt require a specialty welder, it requires the correct filler wire, technically it doesnt require heat treat either if welded in it's annealed state (although the benefits are greatly minimized aside from corrosion resistance if left in an annealed state).

 

Most of my experience is in high tech welding where the embrittlement is a non issue. I would like to look into seeing if my company can provide this welding service but I doubt we could do it cheap enough for the market. We would probably be looking at around 240$ per set.

 

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1 hour ago, calZ said:

The whole purpose of this swap is to do something cheap and readily available. If you use a material that requires heat treating and a specialty welder, you alienate almost the entire target market. 

Exactly, well said.

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I have a question about coil overs used with this swap.  In the first post it was mentioned the WRX coil over would be this swap then later on in the thread the STR units would be used.  Is the rear diff swap and Mustang front brake swap designed to be used with either strut/coilovers?  My 280Z will be more of an autocross/road course use so hope the coil over used has good after market support for road racing.  Don't know much about either WRX or SRT racing and building suspension in general but know good shocks/coil overs, which don't come cheap, are key to handling.  Also, excited at the prospect of utilizing both front and rear 2015 Mustang brakes which opens up great possibilities and aftermarket support. 

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7 hours ago, jsulse said:

I have a question about coil overs used with this swap.  In the first post it was mentioned the WRX coil over would be this swap then later on in the thread the STR units would be used.  Is the rear diff swap and Mustang front brake swap designed to be used with either strut/coilovers?  My 280Z will be more of an autocross/road course use so hope the coil over used has good after market support for road racing.  Don't know much about either WRX or SRT racing and building suspension in general but know good shocks/coil overs, which don't come cheap, are key to handling.  Also, excited at the prospect of utilizing both front and rear 2015 Mustang brakes which opens up great possibilities and aftermarket support. 

Went with srt4 coilovers because they have both a cheap market and high end ones available.  The front spindles are 2014 mustang brakes, which do have plenty of options.

 

I had to drop everything and come deal with the lava situation here in Hawaii so it'll be a few weeks before I can pick it back up.  Good news being that I already have the 315 tires, so I'll be able to drop the car back on its wheels and test it all out once I come back to oregon.

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Invincibleextremes, I am very interested in your pursuit to use the Ford Super 8.8 differential.  I am not ready now but do plan on finally upgrading my extreme Primadonna Z that will put down 750-850 HP with probably 335's in the rear and 285's in the front.  Do you believe that the Ford Super 8.8 will handle that type of HP?  I want to keep my car independent rear suspension as the goal of this build is a reliable street driven Z car that can go over 200 MPH and fully use the HP I will finally have without anything breaking.  If the 8.8 will handle it I think it would be great if you offered a really complete kit so that one can buy it but not have to modify anything just buy your kit and bolt it in.  I know there are many whom are ok with doing a lot of the work themselves but I would be interested in a more bolt on kit to use the 8.8 and still be able to use the Apex Engineering or TTT lower control arms and other parts they offer to improve the performance of the 240Z factory design.

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13 hours ago, primaz said:

Invincibleextremes, I am very interested in your pursuit to use the Ford Super 8.8 differential.  I am not ready now but do plan on finally upgrading my extreme Primadonna Z that will put down 750-850 HP with probably 335's in the rear and 285's in the front.  Do you believe that the Ford Super 8.8 will handle that type of HP?  I want to keep my car independent rear suspension as the goal of this build is a reliable street driven Z car that can go over 200 MPH and fully use the HP I will finally have without anything breaking.  If the 8.8 will handle it I think it would be great if you offered a really complete kit so that one can buy it but not have to modify anything just buy your kit and bolt it in.  I know there are many whom are ok with doing a lot of the work themselves but I would be interested in a more bolt on kit to use the 8.8 and still be able to use the Apex Engineering or TTT lower control arms and other parts they offer to improve the performance of the 240Z factory design.

The super 8.8 in a nodular iron case will handle that no problem.

 

And yes I will be offering a bolt in kit, that's the entire idea with this.  

 

My own personal goal is to have a street driven 1,000 plus hp 240z widebody with 275mm and 315mm tires, so our interests align, that's for sure.

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5 hours ago, Invincibleextremes said:

The super 8.8 in a nodular iron case will handle that no problem.

 

And yes I will be offering a bolt in kit, that's the entire idea with this.  

 

My own personal goal is to have a street driven 1,000 plus hp 240z widebody with 275mm and 315mm tires, so our interests align, that's for sure.

That is GREAT!  My car is a pretty extreme wide body, right now it has old BBS racing three piece 15 x13 and 15 x11 rims with 345's and 285's with half inch spacers so there is even more room to put a wider tire but nobody makes one.  Now that 15" rims are old school my tire choices are almost nil so I am going to buy new three piece CCW's either 17 or 18" or look into what options I can do on re-barreling the BBS as those rims are cool but I am not sure if that process will allow me to go up to a 17" or ?  I was going to go with 1000 HP but talking to Dave at  RIPS Racing I think for long term reliability I will go with their RB34 that will put down 750-850 HP as those versions are doing well as daily drivers in client cars in the UK;  unless Dave says that I can go more HP and still be a daily driver?

 

Again keep up the work as I really would like your kit as I have not seen anything that anyone has the confidence can hold up to these big HP numbers.  I hope you have a kit option that is bolt in for people like me that do not want to deal with welding anything, etc. and ideally have everything look well finished.  I plan on getting my Primadonna Z car back on the car show circuit for the first year after it is done so I really want all of the parts to look show quality and nice besides being super reliable for racing on the streets.  So your kit will have everything to make the 8.8 bolt in and can I also use the Apex or TTT lower control arms with it?  I look at your thread often and am eager to see you complete this kit!!!! Great job!!!

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