Mustang II conversion

[1970 slantroof]

I am done with this discussion at this time. Yes I have read Herb adams book. I also have "Racing and Sports Car Chassis Design" by Costin and Phipps and Race Car Engineering" by Paul Van Valkenberg plus many of Steve Smith's books and race car chassis. The Costin and Phipps book has a section on chassis stress calculations. You should read and understand it.
This may surprise you but I retired in 1988 after 32 years as an engineer so it's not just my experience that trells me I am correct.
I truly believe at this point that you will never be convinced you are wrong and I could care less.
If you feel so strongly about these kits, why don't you campaign to make them illegal.
Howard

 

[Red Barchetta]

I am done with this discussion at this time. Yes I have read Herb adams book. I also have "Racing and Sports Car Chassis Design" by Costin and Phipps and Race Car Engineering" by Paul Van Valkenberg plus many of Steve Smith's books and race car chassis. The Costin and Phipps book has a section on chassis stress calculations. You should read and understand it.
This may surprise you but I retired in 1988 after 32 years as an engineer so it's not just my experience that trells me I am correct.
I truly believe at this point that you will never be convinced you are wrong and I could care less.
If you feel so strongly about these kits, why don't you campaign to make them illegal.
Howard

Gotcha. So if you don't like what people say, you're going to pick up your toys and leave the sandbox. As I said, I would gladly concede that you are right if you can give me some data to support your side. Shouldn't 32 years as an engineer and "over 50 years of rodding and racing and designing, fabricating, and driving race cars" make figuring out those calcs easy? It's exctly weak tech like this I'm campaigning against. Is this too much to ask?

 

[1970 slantroof]

I'm not leaving the sandbox. I will be involved in the forum like always but I refuse to get dragged in an argument just for the sake of it. Just what are your astounding qualifications to even be discussing this subject, let alone act like an expert. If you think an export brace will provide resistance in a vertical plane, there is no need for further discussion. I refuse to engage in a battle of wits with an unarmed man.

 

[Red Barchetta]

I'm not leaving the sandbox. I will be involved in the forum like always but I refuse to get dragged in an argument just for the sake of it. Just what are your astounding qualifications to even be discussing this subject, let alone act like an expert.

Do we all need an engineering degree to ask a question? Should I ask for your permission first before speaking? Should everyone do that? You're the one with the credentials and experience, so bring the tech.

If you think an export brace will provide resistance in a vertical plane, there is no need for further discussion.

If you think that the load on the export brace is only in a vertical plane, then we really do need to stop discussing this. Since the overall movement is actually 3 dimensional, the vertical movement portion would actually be in an arc determined by where the frame rails are flexing. Saying the load is vertical makes your comment questionable.

I refuse to engage in a battle of wits with an unarmed man.

This is not a battle of wits, it's a request for factual data, which you can't provide. You yourself said it's your opinion. Great, that and 75 cents can get you a cup of coffee. Like I keep saying, bring the tech. Help me understand. You are the one with the credentials. You are supposedly the "armed" one. But if all you can come up with is the same rhetoric as before instead of actual data, then I would much rather be unarmed and quesiton your tech in order to find out the truth, than some misinformed lemming who blindly accepts what's spewed out on a message board.

 

[67efivert]

it was originally designied for full frame cars ?????? lol rember guys ford originally designed this suspnesion for the 70's era mustangs and pintos wich WERE unibody cars like ours and rember a good amount of stress is put on our frames now with that cheezy crossmember and lower control arm mount that we have stock with a capped and braced frame id feel safer with the mII set up than stock but thats just my opinion im no engineer but work on cars and trucks daily and dont listen to most of the article crap i read so have a nice day

 

[1970 slantroof]

You are the one who jumped into this discussion with a challenge. you provide the proof. I personally don't care what you know or think. I never said the export brace will only handle a vertical load. Maybe you did. Who died and left you in charge of all posts?
Goodby

 

[Red Barchetta]

it was originally designied for full frame cars ?????? lol rember guys ford originally designed this suspnesion for the 70's era mustangs and pintos wich WERE unibody cars like ours and rember a good amount of stress is put on our frames now with that cheezy crossmember and lower control arm mount that we have stock with a capped and braced frame id feel safer with the mII set up than stock but thats just my opinion im no engineer but work on cars and trucks daily and dont listen to most of the article crap i read so have a nice day

Obviously you don't read much of anything as my post said that the kits were originally designed for full frame cars.

You are the one who jumped into this discussion with a challenge. you provide the proof. I personally don't care what you know or think. I never said the export brace will only handle a vertical load. Maybe you did. Who died and left you in charge of all posts?
Goodby

And who's the "unarmed" one now? You're the engineer. You're the one with over 50 years of experience. It must really chap your hide when someone questions your methods and you have squat to back it up.

I made an observation. Talked it over with someone who is more knowledgeable than I am and he agreed. Are we 100% correct? Maybe, maybe not.

I bring a dissenting opinion to this thread and the best you can come up with is your resume? At least I'm willing to switch my stance with the appropriate data. Seems like the only thing your experience has given you is a hard head. But this is a moot issue for you as you said yourself that you're considering some kind of reinforcement.

To everyone who reads this thread and is considering such a swap and is not going to reinforce the frame or suspension, don't take my word for it and don't take slantroof's word for it. Go research it yourself, get hard data and make the decision based on the data you have.

 

[CloneRanger]

Ooookay.
I too am an engineer (Mechanical), although don't have the 32 years of experience or 50years of background in rodding/racing, but i do have a genitic predisposition to this stuff....... (Family history of engineers)

Basically, as I see it, Yes, the frame rails, when braced, and with the support of the inner fender panels, should be up to the job. However, the lateral loads are a little concerning to me, as without the Export brace (ideally one down at sump level would be peachy!) the front end will flex side to side (no triangulation...).

The Export Brace doesn't carry a significant amount of vertical load (a few lbs?), being a fairly thin stamped piece *bolted* at the firewall. However, the export brace *and* monte-carlo bar will prevent the inner fenders flexing inwards under shock loads... which is why MacPherson strutted cars all run them... (and if you have an adjustable brace you can wind in negative camber in clases of racing where adjustable suspension is not permitted....)
So, I spose the monte-carlo bar does in a way carry vertical shock loads (the export brace is inneficient in a case where both sides flex inwards... the Monte triangulates it all up nicely...) when they are transferred into twisting loads in the inner fenders.

Would I fit MII suspension (Assuming I could get it in Australia?)? no.
Too Short suspension arms for my likings... works, but within a limited travel range.....
Much prefer to tweak the Existing system. cheaper, easier, but packaging sucks. No 32 Valve 5.4 litre Modular for me...
life would be easier if there weren't an engine to prevent triangulation...

Red, look at the way an Export brace is mounted at the firewall. 4 bolts in a line. looks at the Thickness of the steel, and the Depth of the stamping. Now compare it to the Depth of the inner fenders and their thickness. The Export brace is simply not capable of supporting much vertical load.
Heres an experiment for you.
Get an export brace. Clamp it to your work bench (you do have a work bench? or are you a Kitchen-benchracer?) at the stock firewall mounting points.
Lean on the ends. watch them flex and bend......

Ben

 

[Red Barchetta]

...Red, look at the way an Export brace is mounted at the firewall. 4 bolts in a line. looks at the Thickness of the steel, and the Depth of the stamping. Now compare it to the Depth of the inner fenders and their thickness. The Export brace is simply not capable of supporting much vertical load.
Heres an experiment for you.
Get an export brace. Clamp it to your work bench (you do have a work bench? or are you a Kitchen-benchracer?) at the stock firewall mounting points.
Lean on the ends. watch them flex and bend......

Ben

First off, my Kitchen-benchracer is faster than your Kitchen-benchracer.

The experiment you're giving me does not reflect the loads experienced by the export brace. If the load was perfectly vertical, it absolutely will bend. There's no argument there. However, the load on the export brace moves in an arc, actually in 3 diminesions, but I'm only talking vertically and horizontally (forward and back). Since the length of the export brace (a one piece brace, as the 2 peice is very weak and it's the first thing that should be replaced) is fixed, you impede that horizontal movement. Since it can not move both vertically and horizontally, it reduces flex in the frame rails. I probably could have explained that better earlier, but essentially, some of that vertical load is transferred horizontally to the export brace because it moves in an arc.

In addition, the load is not symetrical on both sides of the frame rails. When a car is cornering under heavy load, the front frame rails have a tendency to twist, meaning the body leans to one side while the frame rails try to stay horizontal to the road surface, causing a twisting action. One frame rail would flex up, while the other would flex down. The export brace helps locate the front end, minimizing twist. The Monte Carlo bar provides lateral rigidity, keeping the export brace from spreading out or moving in (not sure if it's clear what I'm trying to say.) Together, they do a good job of triangulating the front end. If you had to pick one, which do you think would allow the least amount of twisting? My money is on the export brace.

 

[Stang2Man]

You all may want to step back and take a look at the original post. This guy mentions knowing where a II is to get all the stuff out of. I don't know how many of you have cut apart a II for this conversion (probably none) but. Just remember ALL Mustangs are Unibody. Full framed vehicles require boxing the frame to install a II front end. And there are an awful lot of people successfully doing this conversion with kits. As I should put out would be more expensive, but a whole lot less labor intensive as cutting out the front end of one car only to attempt to weld it into another. And there's always the fight of distorted metal from too much heat.

Of course my question about the kits is this, do they use a stock dimension sway bar or is there a new specific one to the kit that comes with them?? or do you even get one?

 

[Sundance]

I'll provide the suspention specs you request if needed. So far you want camber per inch travel? What other measurements would you like?

The verticle load issue Cloneranger hit it on the nose. The shear strength of the inner fender panels resist most of the verticle load. The export brace will help, but to what amount...not even worth concern.

Torsional load is an all together differant animal. The loads you are refering to are on two different planes as I understand it. (No engineer here)

If you retain the existing strut rod mounts there is some triangulation. Seam welding the strut rod mounts will help, and you get some nifty tie down loops

Great info and opinions from all. Great thread!

 

[1970 slantroof]

I agree with posts 28,29,& 30. I would like to put some trianglation down at the pan/frame level but that will be tough with headers and whatever in the way. It's interesting to me that the factory engineers who are usually fairly conservative on suspension strength would find it necessary to put an export brace on the 64 1/2 thru 73 unit body cars and then decide it is not necessary on the 74 thru 78 unit body cars. My OPINION is that due to the different suspension loads transferred to the fender wells, it was not considered necessary. One of the points I was trying to make earlier. Of course the subframes could well be much different, I do not know that.

Now for Mr. red barchetta. I would like to bury the hatchet and move on but you continue to make uninformed juvenile attacks on me for some reason. Like the comment I have squat to fall back on. You know nothing about me, what I have accomplished or what I am capable of. When I went to college, we had K&E slide rules hanging from our belts since pocket calculators had not been invented yet. After school I was cordially invited to attend the Korean conflict. When that ended I got a job with a large international company and had a lot of different assignments and by the time I was assigned to the development lab, we had a large room down the hall with a cardlock on the door and a bunch of CAD systems inside. I have not done the math on a problem like this for probably 25 years and you have an inflated opinion of your importance if you think you attacking me is going to motivate me to drag the books and calculator out to "do the math". It just is not that important to me to try and impress you. Sorry.
Lets move on and try to continue to learn about this. NO ONE is so smart that they don't need to learn more. I learned several things out in the shop today.
Peace,
Howard

 

[Red Barchetta]

[ I interrupt your normal thread for this Hijack ]

Look Howard, I have nothing against you. This is an internet forum, and emotions, tone & inflections in voice do not transfer well. I would put money on it that if we were face to face, there wouldn't be any of this perceived tension between us like their is on this board. I couldn’t give a crap about what people say about me on it. But if you’re going to call me out, I’ll play.

With that said, this is the internet and far too often people use their "experience" without any quantifiable data to justify their response. And as you said, I know nothing about you. So giving me a rundown on your history doesn't do much to answer my questions. You put up your credentials as a way to justify your position and then questioned mine. If you’re going to put that out there, then you’re fair game. If you don’t like it, then don’t put it out there. Take your word for it because you’ve been there and done that? Nah, that's OK. I'll keep asking questions until I get an answer that can be proven, given the appropriate information. That way, if I don’t like the answer, I can only blame myself for not asking the right question.

For how long did people think the world was flat? There were sailors who've sailed all their life and they were deathly afraid to sail off the end of the earth. What did their experience give them?

How many people on this board do you think could calculate swing-arm length or roll center height without first looking it up to see what it means? Up until a couple of years ago, I sure as hell couldn't. What about anti-squat? Or how your king pin inclination affects the scrub radius?

If anyone is going to modify the suspension on their car, these are things they should learn. Not just their definitions, but how do you come up with their measurements and why does it affect your car.

A technical question needs a technical answer. I like to know how stuff works and why things do the things they do. Taking someone's word for it might satisfy some, but they're missing out on something else you said. Learning. Learn the how's and why's.

Example, someone comes up to you and says they have a stock engine and they’re looking for a cam to make some more horsepower. After gathering some info on what other engine mods he’s going to do as well as what kind of power he expects, do you just hand the person a cam and say “this will work”, and tell him you know because you’ve been doing it for over 50 years, or do you tell him the specs of the cam first? At least by giving him the specs, he can try and figure out why you recommend such a setup, as opposed to just taking your word and not having any idea why the cam you gave him works with his combo, other than because you said so.

I think that pretty much sums it up for me. We can agree to disagree on what works and what's considered a good answer. If you want to continue to discuss this, you can PM me, or we could start a seperate thread about the structural rigidity of the front end of our cars. Anyone have a Solidworks drawing of an early Mustang?



[ /you are now returned to your original thread ]

 

[1970 slantroof]

Now that we have that behind us, maybe we can learn more about the pro's and con's of this swap. The poor fellow who started this thread has probably moved out of the country. I personally think it is a good but not real inexpensive swap for a driver. Not sure I would want to do it for an open track car. I think for that I would probably start from scratch with a suspension and new front subframe but don't need all that effort and money for a driver.
Howard

 

[Sundance]

The camber gain is -.16 degrees.

 

[Red Barchetta]

The camber gain is -.16 degrees.

Don't know what to make of that number. Is that how much camber gain there is with 1 inch of jounce? I was probably not very clear on what I was asking. What is the camber gain at 1", 2", 3" and at 4" of jounce. Camber gain is usually progressive, meaning there would be more camber gain between 3 and 4 inches of travel than between 0 and 1 inches of travel. If -.16 is at 1", it would be interesting to see where it is at 4" of jounce.

 

[bnickel]

i haven't read any of this thread other than the last page because i am not fond of the mustang II suspension swap into the early cars, because i actually like my shock towers, lol. anyway i just have to say this.

red barchetta you have been spending way too much time over at CC. LOL, but i can tell you have been learning a lot there. personally i don't have enough math skills to even think about all those equations

ok enough of my smart-a$$ comments bat to your regularly scheduled programming

 

[65RumpityRump]

YES,GOD loves all of you guy's,yes that includes YOU!

 

[Sundance]

Yes, of course it is progressive.

At one inch jounce the camber gain is -.16
At two inches jounce the camber gain is -.62
At three inches jounce the camber gain is -1.40
At four inches jounce the camber gain is -2.53

Something to consider; The MII lower arms are the same length as my 65. The MII upper arms are 1/4 shorter then my 65. If you buy the Total Control or Global west kits. The arms would be the same length, as both companies shorten them.

 

[Red Barchetta]

Yes, of course it is progressive.

At one inch jounce the camber gain is -.16
At two inches jounce the camber gain is -.62
At three inches jounce the camber gain is -1.40
At four inches jounce the camber gain is -2.53

Something to consider; The MII lower arms are the same length as my 65. The MII upper arms are 1/4 shorter then my 65. If you buy the Total Control or Global west kits. The arms would be the same length, as both companies shorten them.

-2.53 degrees at 4 inches doesn't sound like much. What we have to clarify to all the readers is that the camber you have measured is camber gain in relation to the vehicle. The next thing we need to take into consideration is camber relative to the road. When the car goes around a corner, the body leans. With this change in body roll angle, positive camber is introduced. Even though the suspension produces -2.53 degrees of negative camber at 4 inches of jounce, that may not be enough to overcome the positive camber caused by the body roll angle. To compensate for this, you can increase the roll stiffness by using stiffer springs, a larger stabilizer bar, or setup the car with more static negative camber.

What's the right solution? Probably a combination of all 3, but remember, there are drawbacks to each of them.

Regardless of what suspension you use, this will be a factor. However, the type of suspension used will make minimizing these affects easier, or harder.