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Discussion in 'Classic Mustang Specific Tech' started by reenmachine, Apr 17, 2005.
That's where the roll bar and/or x brace sf comes into play!
While the roll bar will help a little, it is more of a safety item than a structural item. We will be evaluating just how much a roll bar contributes to torsional stability once we weld our roll bar in.
The front end and floor sections of these early cars are where most of the issues lay.
I have not done any testing of the "X" brace sub frame connectors. I will bet that they are an improvement over sub frame conectors alone, but how much of an improvment they provide is the question.
It would be nice for someone to do some before and after testing.
Speaking only for convertibles....those roll-bars that weld to the crossmembers (I think that is the term) near the floorpans add much more stability than the more cosmetic type (think late model SN95/SN197 here) which connect to the sheetmetal by the windows.
Although they now offer X-braces for verts (none that fit my Global west SFCs that are welded in), I'd have serious concerns about ground clearance with the addtional factory bracing to clear.
As Edbert said, the true roll bars at least a 6pt help considerably. You can talk to any chassis engineer on that point.
By using the longer type sf connectors like the Maier ones, they also help to reduce the wallow effect.
With an unseasonable 65 degrees without a cloud in the sky I must admit that I'm getting much more "road test" in than actual work...
The body shop is finally able to fit me back in a week from Monday for the final panel alignments, side striping, etc. Then I'll be able to add the front grilles, headlight trim rings, enblems, etc.
It's running smooth as silk and driving great!
tooting my own horn
I think the best way to do an SFC is to go right through the convertible subfloor and weld to it. The Tin Man subframes do that pretty well:
I am very happy with this setup and tying into the subfloor seems to (and feels like) it gives some torsional rigidity as well. If SN65 wants to ship his torsional-deflection testing equipment to CA, be my guest! The only thing I would change is to make it longer and attach at more points, a la the Maier Racing model.
If this ends up not being stiff enough, I might consider jacking rails from the SFC to the rocker panels, or a Mustangs Plus style chassis strengthening, where sheet metal connects subframe to rocker. (or even subframe to subframe in the rear, kind of a rear version of the convertible subfloor) I'm still not convinced of what is the most efficient use of metal.
I think Reen welded his SFCs to the original floorpan, (too lazy to look) and that HAS to add more torsional strength than just a free-hanging SFC.
Still can't find the "flattened X" from dr. gas . . .
Thanks - I looked in their catalog, and all I could see were flattened bends that you could cut open and weld to each other to handmake a flattened X. I checked all over the site. Am I missing something? That sounds like an ideal setup, I could replace the Magnaflow X with their X. But then, it would have to be splayed out on one end (to go to headers) and together on the other (to go through the tunnel). The plot thickens.
take a look at the spintech SFC'S i found at mustang depot.
it looks like you could still use the regular GW, TCP style SGC's in conjunction with these and still be able to add the X-brace as well. not 100% sure of that but it looks possible at least.
Perhaps Jay can answer, since you linked to his site and all
Oh and while I am at it...did ya'll notice the Julian brothers are considering offering their custom esheetmetal from SN95 as a kit? Anyone wanna help convince them?
I just called them to order mine. They can basically flatten anything they offer. It comes with the extensions flattened too. We just used the flattened x-pipe and openned the ends to meet round tubes.
Those just hug the floor to allow for the side exhaust to pass through. I don't think they would work with other systems. They're also good for cars worried about ground clearance and they look stock. Pretty cool
I love the idea of those Spintech SFCs, what with welding to the floorpan. It's just that they don't look to be as beefy as the Tin Man ones and therefore wouldn't have as much beam strength. But I'm just guessing from the looks of them, especially the bent out flanges. And I would like them to be closed at the top . . .
anyone know what gauge these are?
that's one of the reasons i liked them because of ground clearance. are you sure you couldn't use a tubular SFC that would run over them, like a GW or TCP style? it sure looks to me like it would work but then again pictures on the 'net can be deceiving
Not positive but I doubt it. These just came out so I haven't had them in hand yet.
They're made from 13ga
well if you get a chance someday maybe you could check to see if it's possible. it's just got my curiosity piqued now is all.
I dropped the 'vert off in Phoenix yesterday to get all of the final panel alignments set, etc. and took it for a nice spin. It was great to be in actual convertible weather -- I've been driving it around freezing my butt off up here in Flagstaff!
I felt that it was broken in enough to really get on it a bit more and was genuinely surprised by the power and the smooth delivery. The car is fast! With all of the 500-600-700+ hp numbers the magazine covers bombard you with these days you start to think that 350hp is moderate. In my opinion it's the perfect number. The car is quiet and smooth when you want to cruise town or glide down the freeway, but when you get on it and get the revs up it really runs! I had a customer with me who I'm helping build a '67 fastback with a tweaked '04 Cobra motor and he was really surprised at the power. After the ride he said, "My car will have 200 more horsepower than this thing and I have no idea what the f*** I'm going to do with it!"
I say that another penny spent on horsepower over 350 is a waste of money if you actually want to drive the car frequently.
I'd agree if you mean RWHP, if you mean FWHP then I'd go to 400
Seriously, for anyone who has been driving their classics for decades with the 200-271 rated 289s (like me)...that extra ooomph is seriously daunting, and quite a suprise when it comes in, even for those of us used to driving "performance" OEM automobiles. I honestly wonder at those magazine articles about the 750hp-NA cars or the 1,500 dual turbo rides...WTF can you do with that on the street, or even the track with DOT radials?
I'll take a streetable/relaible/smooth 350-400 any day of the week. More than enough to keep the "PF" up there.
The older I get, the less I feel I need under the hood. I started my Mach 1 project when I was in my 20's and now I am well into my 30's and I am left scratching my head at why I spent all that money building a 500 horse engine.
Drove the car for the first time today, and it is crazy fast...and I never even cracked the back butterflies.
I agree 100%...for a fun driver, 350 at the wheels is PLENTY.
Well I guess I'm on some kind of ego trip cuz I love the stinkin power comin out of my car. Is it streetable, not really but who cares. I'm havin a ball. Still working on hookin first gear but I'm almost finished working that end. Then I'm going to turn up the boost to go past 500 on the ground. Why you ask? Why the hell not! Shoot, my hands are shakin so bad I can barely type he he