do i really need the fc subframe?
#1
nother rican witha rotary
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do i really need the fc subframe?
if i wanted to do the sus swap? also has neone done the rear? planning on doin an all round 5lug swap mayb...i know it's been done before, i remeber seein a 1st gen with fd wheel's on it from florida...dont know if that same guy's on the forum though
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the FC isn't bolt in either, I'd reckon (for the rear that is)
the front is possible to bolt right in, but it will be further forard, and look weird.
the front is possible to bolt right in, but it will be further forard, and look weird.
#7
Check out the roadster build up. One of the projects is the Miata IRS. Let's just say it involves cutting out the frame rails...
https://www.rx7club.com/1st-generation-specific-1979-1985-18/mega-rx-7-roadster-build-pics-361918/page3/
I put this stuff up for you guys. Learn from it. The FC3S suspension swap is coming as well. As far as I can tell you will need the FC subframe, or what would you bolt the lower arms to?
As far as the 5 lug stuff goes, many people just bolt on spacers with 5 lug conversions. They don't actually swap out the suspension. That's probably what you're seeing 99% of the time.
https://www.rx7club.com/1st-generation-specific-1979-1985-18/mega-rx-7-roadster-build-pics-361918/page3/
I put this stuff up for you guys. Learn from it. The FC3S suspension swap is coming as well. As far as I can tell you will need the FC subframe, or what would you bolt the lower arms to?
As far as the 5 lug stuff goes, many people just bolt on spacers with 5 lug conversions. They don't actually swap out the suspension. That's probably what you're seeing 99% of the time.
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#8
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I'm going with the FC subframe front and 5-lug adaptors in the rear. So far I've got the subframe physically on the car and attached with the two front stock bolts from the FB subframe. So sort of shim will need to be fabricated for the rear because the FC frame rail appears to come down compared to the FB which is flat all along. I may end up just making the shim out of square tubing and then welding it to the frame, then the shim would become the mounting point and I wouldn't drill into the frame at all. I'm not sure if this is a really secure option but so far I can't see a problem because the front bolts take at least 75% of the side load because they are much closer to the pivot point of the control arm. The odd thing is that Abeomid who is almost done the swap didn't need any shims at all. I know I have an S4 front end, maybe his is an S5 and it's different?
Grant
Grant
#9
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I don't see the point in all this.
There's no real need to get a 5 lug conversion. Most wheel shops will be able to supply wheels in 4-lug versions, overhere most wheels can be drilled to fit any setup (they come in undrilled if required) If you don't like the old-style pattern, you can either swap to 84-85 setup, or have the OEM S1/S2 redrilled. On my car the builder (I rebuild most of the car by now, but someone did the work first time) went the other way around: 85 rear axle was redrilled to accept old style bolt pattern (to fit the 3 piece wheels) Every good machine shop will be able to do that, or maybe go to 5-bolts aswell. A lot safer then all those spacers etc. Those things sure wouldn't be accepted here, and I really can see why.
As for the subframe: I said this before, and will post th link again:
http://www.zerniener-autohaus.de/html/fb_200_ps.html
Just scroll down a bit, the pics speak for themself. An FC subframe is just out of place under a stock SA/FB body. Don't forget track will increase to: you'll need either a widebody, or fender flares (or like the German car modified oem fenders).
These guys in Germany have tested the whole thing, and then decided to go way further, and cut the whole nose off, and replace it by a FC unit.
There's no real need to get a 5 lug conversion. Most wheel shops will be able to supply wheels in 4-lug versions, overhere most wheels can be drilled to fit any setup (they come in undrilled if required) If you don't like the old-style pattern, you can either swap to 84-85 setup, or have the OEM S1/S2 redrilled. On my car the builder (I rebuild most of the car by now, but someone did the work first time) went the other way around: 85 rear axle was redrilled to accept old style bolt pattern (to fit the 3 piece wheels) Every good machine shop will be able to do that, or maybe go to 5-bolts aswell. A lot safer then all those spacers etc. Those things sure wouldn't be accepted here, and I really can see why.
As for the subframe: I said this before, and will post th link again:
http://www.zerniener-autohaus.de/html/fb_200_ps.html
Just scroll down a bit, the pics speak for themself. An FC subframe is just out of place under a stock SA/FB body. Don't forget track will increase to: you'll need either a widebody, or fender flares (or like the German car modified oem fenders).
These guys in Germany have tested the whole thing, and then decided to go way further, and cut the whole nose off, and replace it by a FC unit.
#10
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Hate to say it but those guys used excellent fabrication to try and make up for just basic bad engineering. If they were willing to add on the nose from an FC they should have just redilled the front bolt holes back far enough to change the caster, would have been infinately simpler. I can't help but think thay their project, while very well done, was not thought out well in any way. As for custom redrilling: I autocross my FB because I'm not made of money (otherwise I'd have a Miata, honestly); I don't have the cash for custom rims and I don't have the cash to pay to have every set of rotors I go through custom drilled. I also don't have the cash to buy the CP racing big-brake kit and rack and pinon (which is horrible for AutoX anyway) but I do have the money to drop in an FC subframe and get both for less.
If they had wanted to they could have made it work with much less effort. And the track width is compensated for by the higher offset of the FC wheels, which is evident in one of the pictures on their website. For those thinking about the swap: go for it! I've got relatively minimal fabrication skills and a semi-well equipped shop and I feel totally up to doing the whole thing myself, although I guess we'll just have to see when it's rolling (literally) in another few weeks.
Another possibility that is very slight is that the Euro front-end is different in some way and so the attachment points are different, but honestly I don't think so.
Grant (Currently looking at an FC subframe bolted ,by the front two only, into his FB)
If they had wanted to they could have made it work with much less effort. And the track width is compensated for by the higher offset of the FC wheels, which is evident in one of the pictures on their website. For those thinking about the swap: go for it! I've got relatively minimal fabrication skills and a semi-well equipped shop and I feel totally up to doing the whole thing myself, although I guess we'll just have to see when it's rolling (literally) in another few weeks.
Another possibility that is very slight is that the Euro front-end is different in some way and so the attachment points are different, but honestly I don't think so.
Grant (Currently looking at an FC subframe bolted ,by the front two only, into his FB)
Last edited by grantmac; 11-02-04 at 07:09 PM.
#11
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If you move the subframe, the motormounts will move with it, that's why they decided to go this way. You are right about the possibility of doing this, but you'd have to re-inforce the new drilled frame (as Mazda did) or you'll seriously weaken it. The track width is not compensated at all as far as I know: the track width on FC's is wider then on SA/FB's: by using a FC subframe and wheels, you'll end up with a wider front. Track is the center of the tires, how can this be compensated, unless you use non-stock wheels?
As for custom drilling brake-rotor's: overhere a lot of replacement (not Mazda of course) material can be ordered undrilled, and will then be suited to your setup. No big deal.
The subframe swap keeps being advertised as a good way of getting a better/brake/steering/suspension setup, but I still haven't seen ANY pics of a stock bodied car with the setup finished. I'm not saying that it's not possible, but why doesn't anyone make pics of this? I just need to see to believe, so get those camera's out and convince me (I have an FB waiting for a simular treatment if I'm sure it's safe and clean)!
I want the following shots: before shots from the front and side, during shots so can see what's involved, and after shots from the front and side to see how the wheel is situated in the arch. Again: on a stock bodied car please.
As for custom drilling brake-rotor's: overhere a lot of replacement (not Mazda of course) material can be ordered undrilled, and will then be suited to your setup. No big deal.
The subframe swap keeps being advertised as a good way of getting a better/brake/steering/suspension setup, but I still haven't seen ANY pics of a stock bodied car with the setup finished. I'm not saying that it's not possible, but why doesn't anyone make pics of this? I just need to see to believe, so get those camera's out and convince me (I have an FB waiting for a simular treatment if I'm sure it's safe and clean)!
I want the following shots: before shots from the front and side, during shots so can see what's involved, and after shots from the front and side to see how the wheel is situated in the arch. Again: on a stock bodied car please.
#13
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Well I'm gonna probably have wheels bolted to mine in two weeks, although it won't be ready for the road yet. Also the wheels I'm using are 6" wide with +50 offset so that'll make a difference.
Grant
Grant
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Originally Posted by grantmac
Well I'm gonna probably have wheels bolted to mine in two weeks, although it won't be ready for the road yet. Also the wheels I'm using are 6" wide with +50 offset so that'll make a difference.
Grant
Grant
Of course I was talking about stock FC rims. yours don't sound very "stock" to me. Don't forget to post pics!
#15
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I'll try for pics, but I have no digital camera. The rims really aren't far from stock GXL which are 6" with +40 offset, if these clear by as much as I think they will then the stock GXL and perhaps TII ones shouldn't be a problem. Also as for being more narrow in the rear, I realized I forgot to add I'm going to be using wheel adaptors to change to the 5 bolt pattern in the rear and that these ones are specifically made to mount TII wheels to a GS or GSL 1st gen.
Grant
Grant
#16
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you see, it's ALWAYS the same thing: people keep telling me it's bolt in, and keep showing me how the subframe is in. Well, I know that. What I want to see is how the stuff looks once the wheels are on. How does it behave, how does it look. Does everything clear? It's strange that this write up is on the web for ages, but I never saw the follow up: steering, wheels...
#18
Originally Posted by rotary emotions
you see, it's ALWAYS the same thing: people keep telling me it's bolt in, and keep showing me how the subframe is in. Well, I know that. What I want to see is how the stuff looks once the wheels are on. How does it behave, how does it look. Does everything clear? It's strange that this write up is on the web for ages, but I never saw the follow up: steering, wheels...
#19
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Well my wheels just won't quite clear the massive calipers on this thing, other than that the swap is nearly finished. I made up the rear subframe mounts with some 1x2" channel iron welded (flux-core wire feed) to the frame, it certainly looks like it'll handle that job well enough; unless it was a rally car I wouldn't worry about it. I'm gonna either have to run 10mm spacers on the front or trade for some GXL wheels. The good news is that with the wheels mounted 10mm out (eyeballing it) they can go though the full range of steering no problem without rubbing on the fender. There is a fair amount of caster but I don't see it being a problem with the handling, at least not for my intended purpose. I expect I should be done with the swap by Christmas at the latest.
Grant
Grant
#20
Rotary Enthusiast
Originally Posted by rotary emotions
you see, it's ALWAYS the same thing: people keep telling me it's bolt in, and keep showing me how the subframe is in. Well, I know that. What I want to see is how the stuff looks once the wheels are on. How does it behave, how does it look. Does everything clear? It's strange that this write up is on the web for ages, but I never saw the follow up: steering, wheels...
As for so called "follow-ups" some of us have other things to do than sit on the forums all day. Anybody that has been interested in doing this and started on it have contacted me and I have give them more than enough information from my experience.
http://www.bcrx7.com/modules.php?op=...howgall&gid=17
Pictures of the steering and wheels on the car are on there.