Ford Super 8.8 irs swap thread. Rear brakes too

[mtnickel]

2 minutes ago, jpndave said:

 

All these rods and points might not be the same length or location but have to move in the same arc and planes as the suspension. If not, then the effective lengths change as things move and bump steer happens. Again, it's all in a 3 dimensional world and the steering has to stay constant in relation to the wheel/knuckle as all of this moves or you toe in or out depending on what each wheel is doing. The double wishbone is easier to control more exactly but a strut is easier to package and cheaper with acceptable changes.

 

There are a couple of really good books on the subject of suspension and some threads out there that are helpful. I'll have to go look at my library and post a few up. Properly designing the rear is one thing but throw steering in the mix and it gets all sorts of complicated.

 

Ya, it’s all a bit of a mess. The original poster does seem to have a pretty good handle on it I gather. 

The inner pivots needing to match only holds true when the spindle is held static.  But like he said, since the tie rod moved outboard it’s ok that the inner pivot moves as well since our main goal is to have the control arm and tie rod be parallel and roughly the same length. Exciting stuff. If I wasn’t so deep into my setup, I’d be exploring this a whole lot. Brake, suspension, cheap and readily accessible beefy diffs. Lots of pluses. 

[mtnickel]

1 minute ago, Invincibleextremes said:

Agreed.

 

I find I ironic that my 1st gen mustangs, and my firebird, and my 69 charger all have double wishbone, and my only car known for handling (although my 68 firebird is no slouch in that dept) has a strut.

 

In fact, I find it downright amusing that most modern cars are strut based.

All in the name of weight and cost savings. Heck, my 93 and 97 accords had double wishbone front and rear!

[Suchfun240z]

I am very interested in this setup.  When do you think you will have kits ready to sell? I’m looking forward to reading you write up on front brakes. Thank you for helping us all out! Keep up the good work!!! 

[Invincibleextremes]

1 minute ago, Suchfun240z said:

I am very interested in this setup.  When do you think you will have kits ready to sell? I’m looking forward to reading you write up on front brakes. Thank you for helping us all out! Keep up the good work!!! 

Uncle Sam has me busy for a couple weeks, after that I'm finishing the install on my own datsun, drafting up the shapes once I'm happy with them, and having it all laser cut and see what else can be done.

 

A month or two tops.

[Suchfun240z]

Sweet!! I think I’d be interested in a tacked up kit.  

[takeuchi]

20 hours ago, Suchfun240z said:

Sweet!! I think I’d be interested in a tacked up kit.  

me too

[Invincibleextremes]

2 hours ago, takeuchi said:

me too

Yeah, I think the best situation for everyone involved is for me to tack every thing in a jig for it to stay true, and let everyone either weld it themselves, or trade favors with a welder etc...  

[neruve]

1 hour ago, Invincibleextremes said:

Yeah, I think the best situation for everyone involved is for me to tack every thing in a jig for it to stay true, and let everyone either weld it themselves, or trade favors with a welder etc...  

Are you gonna design the rear knuckles to use 05-14 front brakes? Because that would be sweet. It'd look awesome but more importantly it would be nice for a track car to have a few extra rotors and calipers and it can go on any position of the car.

[caperix]

What material are you using? Will a mig be able to be used to finish the welding or will a tig be required?  You had mentioned using nissan bearings as well, do they use the same bolt pattern as the mustang parts or do you plan on offering different drilled faces?

[Invincibleextremes]

On 6/1/2018 at 11:48 AM, neruve said:

Are you gonna design the rear knuckles to use 05-14 front brakes? Because that would be sweet. It'd look awesome but more importantly it would be nice for a track car to have a few extra rotors and calipers and it can go on any position of the car.

The face itself doesn't accept the calipers, to use 1995 or 2014 rear brakes it will come with a bracket to work with the caliper you want.  So I see no reason why you couldn't use any caliper you wanted, so long as you could make up some sort of bracket to fit.

[Invincibleextremes]

6 hours ago, caperix said:

What material are you using? Will a mig be able to be used to finish the welding or will a tig be required?  You had mentioned using nissan bearings as well, do they use the same bolt pattern as the mustang parts or do you plan on offering different drilled faces?

The Nissan and the ford hubs are completely different.  And since techno toy tuning offers a really nice Nissan part for a decent price I don't think I'll be offering a Nissan specific upright.  I could drill the holes for a Nissan hub if needed, but I'm not seeing any reason to bother except for people who really want it for some reason.

 

Still debating on material, meaning towards something mild, to avoid cracking, and definately won't be stainless.  Open to suggestions actually, but I see no reason why someone with a mig and gas bottle couldn't finish it themselves.

[neruve]

I think mild would be fine. Plenty strong. Cheap. Easily weldable and can be painted or powder coated. 

[ISPKI]

If you get this project going with enough interested parties, maybe you could offer it in different materials, for an increase in cost obviously.

 

4130 would be an ideal alloy, great for conventional welding, much higher strength and toughness than low carbon alloys, far better stability during the welding process and the high % of Nickel and Chromium resists corrosion in case customers do not want to incur the extra expense of coatings. Cost would be somewhat higher depending on your supplier, although McMasterCarr has similar size material for similar pricing to low carbon steels.

 

If anyone needs the welding done, shoot me a PM.

Edited June 5, 2018 by ISPKI

[Invincibleextremes]

I'll look into 4130, it's easier to machine, so my brother will have an easier time with providing me with the perfect fit spindle pin sleaves...

[jpndave]

4130 easier to machine than mild steel? Maybe close to the same if annealed which it typically is not. Usually comes normalized which is going to be harder than mild steel, not terrible but definitely harder. If you go to a thinner section it would likely be easier than the large thickness parts. Welding is certainly doable but you need to be more careful with heat zone, ideally post treat to normalize. Choose filler carefully, fit properly, etc. I plan on using pretty much all 4130 on my car on what I add in the cage, floors, etc. It is stronger if treated correctly and can be lighter at the same strength if you go thinner wall. For example I'll use 1-1/2" .095 tubing in the cage where you would normally use .120 wall to get a similar or maybe a little better strength and a lighter part ~20%. But you have to be careful not to make it brittle or soften things up to the point of mild steel strength with the thinner section which is then weaker. And it is MUCH more expensive. Not insane but substantially more for material. 4130 is good for high performance thin walled structure type applications. Any of the energy transfer parts like hubs/axles look at 4340 or even 300M is best unless you get into some of the new "wonder alloys" and proper heat treat. 300M isn't stronger than 4340 natively, it just allows you to heat treat to a higher level without getting brittle which is how you get a much stronger part.

 

4130 might be a good option but cold rolled would likely be fine for most applications. The thicknesses you are showing here are plenty IMO. I'd look at bracing and structure a bit rather than throwing mass at the parts. I'll bet that it could be done thinner and still keep plenty of strength even in mild steel. That saves money and weight. 4130 would be much thinner.

 

Generally you can get more strength three ways:

1. mass
2. stronger materials
3. better design/engineering

The second two are much better for performance. Design is free other than the time to do it which in the business world means money.  But only costs on the initial setup, free on everything after that, maybe even cheaper if done right. Materials - cost is higher raw cost and often higher fabrication/heat treat/procedures. You just have to weigh out what it's worth to you or whoever is going to be buying it.

 

Not trying to offend here, some of that is my opinion but based on facts and how things are done in higher performance applications. Every build on here is done differently and one of the things I really appreciate and enjoy on this forum is the tact that is generally afforded. Everyone's vision and budget is different and there is room for all of that here.

Edited June 6, 2018 by jpndave

[jpndave]

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.

[Invincibleextremes]

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 June 8, 2018 by Invincibleextremes
Spelling

[ISPKI]

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.

[DeathByNissan55]

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

[Invincibleextremes]

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.