autopaul

i remember talk a while back of people wanting to do fc rear irs and outruling it because it is iether too outdated of a system or too hard to fabricate to work, now my question is whether anyone has made a custom irs using turbo to of fc components but different mounting points or any such rear end, kindof like this

http://kitcarmag.com/howto/5588/
but instead of ford nine inch components making a case and use turbo 2 stuff, a kindof reingeneered t2 rear end for a fb,

this is an important question for me as i love to do both drag and rally racing in my 7, and i want something strong that will take clutch drops, and nimble at all corners, for the front i already have swapped the fc front subframe and this is another reason, now i can use 5 bolt front and rear, and turbo2 brakes all around,

i know there are other options and i have researched them, im just wondering if anyone has thought of this before,

my past ideas for this included using turbo2 internals and custom axles somehow in a solid/live axle and turbo2 brakes, if anyone has any useful information it would be much apreciated,


also im looking for a thread a while back that i saw it had someone redesinging fd suspension for a v8 swap or something and contemplated a ford 9 inch, it was a huge thread, if anyone remebers,

thanks
Paul

autopaul

here is a better idea of what i want to accomplish, it uses stock center and end components but an aftermarket way of holding it, this way you could adjust everything about it, keep in mind that the help you give me, if successful on my own car could turn into a kit specific to the fb
imagine a bolt on irs kit using turbo2 hardware, ya its far fetched but not that far,



http://parts.factoryfive.com/newcata...ctures/irs.jpg

kenn_chan

good question Paul, I have often wondered the same.

Front crossmeber bolts over with minor mods
seat rails are interchangeable,
transmissions are interchangeable,

It seems to me as similiar as the cars are, the major difference lies in the rear frame I would think that if you were to drill out the panels where the rear floorpan, and strut mounts etc are you could possibly weld the FC floor pan to the body of the SA/FB.

I have never had two of them sitting side by side long enough to take the measurements though.

kenn

autopaul

im not really looking to modify my car in that way, if i wanted a fc i wouldave bought an fc, which is where the bolt on kit comes into play, im just wondering if anyone had suggestions as to where to put links, or how to modify the fc suspension as i go, what are the flaws i should eliminate, i want to be able to bolt this onto another fb if mine gets totalled or if i decide to do a ground up racecar or something, then i can swap everything over, and if it work a kit that encorporates fc components as apposed to aftermarket components would be much less expensive.!!
i want to run my stock rear end untill i figure out what i really want to do with this rear end, and if i can desing something that works good for me then many more on the forum could also benafit, and copy a do it yourself writeup, it was easy enough to do the fc front subframe, and i dont see why it would be soo hard to make a kit for the back to bolt up too,
thanks for the posetive response ken thats truly the idea i had is to make everything about my car generic and swapable with fc parts, im halfway there,

Paul

autopaul

ok im replyiing to my own post again, not a bump, but i found a great picture that may help determine whether making a custom irs, for the t2 parts is possible or rediculous,

it looks promising,

http://img262.echo.cx/my.php?image=picture0175ri.jpg

http://img262.echo.cx/my.php?image=picture0188hl.jpg



found this on the 2nd gen forum, i think that the semi-trailing arm". can be ditched for an adjustable lower ladder bar type system and connected to a housing made around the 3rd member and housing, and mounted to the frame using lateral supports, if you know what i mean structurally, my idea is to copy the picture i posted earlier of a ford nine inch irs system, " http://parts.factoryfive.com/newcata...ctures/irs.jpg "

now i had some more questions i was trying to work out in my head, i noticed in the picture that the upper controll arms for the ford irs system are shorter than the bottom,
when i desing my system is there a formula for the length of the top and bottom controll arms should i copy the fc measurements directly, and just redesign the semi-trailing arm,

i need somebody who knows theyre irs and suspension systems to give me some hints, cause i can make it and do it precisely but i need to know what should be improved and how to do it,


thanks
Paul

toxic_d

paul I hope it would not have to be that that built for our application. That looks like i weights a ton... I will get back to you about the formulas, just have to put my hands on my reference materials.

Toxic_d

autopaul

im making the whole thing out of chromoly tubing for one, the ford one looks allot bulkier than it really is, included in the pic is a sample domestic style frame that its welded to, so eliminate that, and imagine the whole thing in chromoly, basically a cage desing for the pumpkin and controll arm flanges welded to it,

i will be doing the same style design as one of these aftermarket weldon domestic units, but in chromoly, with wieght in mind,

thanks toxic d that would be great if you could, i heard that there is a few problems with the fc irs, i hope ill be able to adess all of them before making a prototype, i still dont know everything about the fc irs workings though, does anyone have a diagram, or layout, thanks,

Paul.

autopaul

http://photobucket.com/albums/b345/a...aintrx7hub.jpg a

few questions about the fc hub itself what is front and back,
im going to be at the wrecker today so i can take measurements and look at the current desing ill keep you guys updated with my findings and problems, im going to be measuring off of a non turbo car, hopefully all measurements are the same, i think they are,

what are some important measurements to take, im going to be learning the fc irs inside and out so anything you can tell me about it would be great too,
thanks again
Paul

autopaul

ok i just got back from the wrecker and i realized the fc suspension is much differen than i thought, i will have to re desing the whole thing, but its funny cause it doesnt change my plan at all,

here is a general idea of the two different types of independant rear suspension for those who are wondering,

fc has a mix of them both, but ill be convetting fully to a multi link suspension

Multi-link suspension
This is the latest incarnation of the double wishbone system described above. It's currently being used in the Audi A8 and A4 amongst other cars. The basic principle of it is the same, but instead of solid upper and lower wishbones, each 'arm' of the wishbone is a separate item. These are joined at the top and bottom of the spindle thus forming the wishbone shape. The super-weird thing about this is that as the spindle turns for steering, it alters the geometry of the suspension by torquing all four suspension arms. They have complex pivot systems designed to allow this to happen.
Car manufacturers claim that this system gives even better road-holding properties, because all the various joints make the suspension almost infinitely adjustable. There are a few variations on this theme appearing at the moment, with differences in the numbers of joints, numbers of arms, positioning of the parts etc. But they are all fundamentally the same.

http://photobucket.com/albums/b345/a...=multilink.jpg

Trailing-arm suspension
The trailing arm system is literally that - a shaped suspension arm is joined at the front to the chassis, allowing the rear to swing up and down. Pairs of these become twin-trailing-arm systems and work on exactly the same principle as the arms in the coil spring type systems described above. The difference is that instead of the arms sticking out from the side of the chassis, they travel back along it. If you want to know what I mean, find a VW beetle and stick your head in the front wheel arch - that's a double-trailing-arm suspension setup. Simple. It's used mostly in older cars and beach buggies now.

http://photobucket.com/albums/b345/a...railingarm.jpg

i just need to figure out where im mounting the links as opposed to what,, ?


is anybody here a suspension engeneer that can tell me this,

autopaul

ok replying to my own thread again, yet with more useful information, ive done allot of searching and found someone on a kit car forum who has actually done this!!! there are 2 possible ways it can be executed, but i still need to find the formulas for upper and lower irs controll arms,

heres a site about "Robs" kit car where he uses an rx7 donor car and re engineers the irs, i swear it was like the idea came strait out of my head and landed on the pictures at this guys site, my jaw dropped when i saw it, (warning it may not be as exiting for you,)

http://www.mindspring.com/~robmk2/

its incredible, im not sure if he even did any calculations for the length of the upper and lower controll arms other than that they seem to be a standard kit car size and it seems to work other than i could imagine that the halfshafts have some in and outward movement, (probably not a big deal)

if your wondering why this is all posted here today, its cause i had a day off work and i got borred, so i went to the wrecker and did some measuring, and it turns out that all measurements other than halfshaft lengs are useless to me, but it was an inspiring trip nonetheless,

keep in mind i Will be making a kit for fb application if this works out for me, so speak now or forever hold your peace,

thanks
Paul

autopaul

here is the other option i am considering its called a De-Dion rear end setup its basically a mix between the irs components and a solid shaft connecting them, with a four link style connection to the solid shaft, this person used old skyline parts, and it turned out great, just another option i thought of while cruisin the kit car forums,

http://au.geocities.com/phil1rowe4/rear.html


http://www.locostusa.com/forums/viewtopic.php?t=65
heres the site that links to it, and discusses the type of rear suspension,

even with a simple setup like this i will be able to use turbo2 components on my car and utilise the strenght of the turbo2 posi, think of how easy a turbo2 swap would be then, i would have all fc suspension, and it would all just bolt up, maybe just get a driveshaft shortened,

i am getting into this project as fast as i can cause right now im cruisin my car with an open diff with ugly 12a mags in the rear and motegis up front, so instead of spending the time and money trying to get a gsl se rear axle which would match my front boltpattern i am waiting a month or two and doing it right the first time and saving money, just my reasoning,

thanks
Paul

toxic_d

That De-dion looks like a simple setup... I have not yet gotten that formula for you will be looking for is in a bit could not locat it in my chassis mod book.

autopaul

cool thanks for your help, one thing about the dedion rear wouldbe i would have to make a custom bracket that monts to all three points on the stock fc rear and make an extremely precise jig for welding it because once it welding theres not allot of adjusting you can do!

do you think you could give me the title of that book aswell its always nice to upgrade your car library, that information is always useful, and if anyone can think of any other books too, but for now the formula would be great, thanks again for your help toxic d

toxic_d

The book that I am trying to find the info in is HP books "How to make your car handle"

There is another book I wanted to pickup about chassis design but have not done so yet.

In the HP book mentioned, there is a mention of calculating sprung vs unsprung weight. It is ideal to keep the sprung weight as light as possible and to reduce the unsprung weight for better handling in the bumps. The De-Dion design gets knocked for waste of space in the book.

Semi-trailing arm suspension setups typically exibit roll-steer...

It seems that after running thru this quickly idon't have an answer for your question yet... just some calculations for roll center and such. Keep in mind that a multi-link design allows for camber and caster adjustment as well as reducing unsprung weight and that is again a good thing. I will check around at some engineering forums for you.

Toxic_d

autopaul

heyy thanks allot toxic d, youve been a great help, thatd be great to get the formula, i think im gonna try and email the guy who did this same thing to his kitcar, and see what dimensions he used and what he would do differently

thanks i think i might pick up those books if i can find them.

yes i didnt really want to go the route of a dedion because its little advantage over solid axle, and itwould be in my oppinion more difficult to make as apposed to a proper multilink which i plan to make,

thanks agian
Paul

TurboIIGuy

why put IRS on a first gen when you can buy a miata and but a 13bT in that and roll around on Tein coil overs?????
Yeah I know the miata is nowhere near being in the same league of how sexy an FB is but drive on one with the setup.......I did!!!
AND NOW I AM A BELIEVER!!!!!!!!!!!
Seriously though its awesome....

autopaul

Car:
84GSL, 87Turbo300+whp
Gender:
Male
Biography:
I like to drive.........RX7s
Location:
Los Angeles
Interests:
Driving RX7's....
Occupation:

your rx7 is modified with turbo2 parts right, turbo2 guy you should know its all in the name of being a first gen owner,


update i just emailed rob from the locost kit car website and am waiting on a reply hopefully he can give me some answeres to make this swap a go,

thanks
Paul

boostedHULK

iTrader: (1)

from what i read in the post, you seem to want to keep it relatively stock but with the irs from a second gen. i am just gonna go tube frame in the rear, and put some panels over it. It'll make it much easier on me, as i can just fab up any mounting points i need, weld my camber plates for the struts in solid, should make it a lot easier, and what wondering if it was the idea of keeping yours as stock looking as possible the only reason you don't do it this way?

autopaul

i have a 6ptcage in my car and i pondered the thought of tubbing it also, but that eliminates the idea of making a kit that people could buy from me then supply thier own parts iether an na diff from a fc or turbo2 diff and componentes w/e but i wanted it to kindof correspond with people doing the fc front subframe swap, at the begging i want to do it so it can be reversed and a solid axle can be put in place if needed, also didnt want to encorporate it into the car incase somehow it gets written off, then i have to redesing it into a different car,

what type of irs are you doing? just curios or are you making a custom 4 link solid axle type setup?

please anyone who has put any kind of irs in thier car show us your setups, any information and pics are great help

thanks
Paul

saltyslug

find a older jaguar rear end with the brakes on the inside. These rearends are capable of 500hp(they use them alot on small-bigblock hotrods). You can polish these things to chrome also if you want(seen it done). Also a few older vettes had IRS rears. I know it sucks to put american parts in the rear of these but they would hold up to heavy horsepower. I know the pads and rotors on the jags are huge also, you just cant see them.

autopaul

cool idea but i feel that would cost an arm and a leg, at any wrecker near me, again, this is meant to be a bulletproof cost effective rear end, my car is very light so i wont need as big of brakes, and i definately dont need monster huge brakes, t2 stuff will be plenty, plus making a kit for people to use thier own parts would be impossible,

i will keep that in mind though, thanks for the input saltyslug
Paul

autopaul

ok, ive been searching and searching, and i am stuck on this project at the moment, i really think it will work and that i will be able complete it within 3 months easily, and start making kits soon after that,
somebody help me with this,!!!!
heres my problem, i need to figure out what lengths to make the top and bottom controll arms, ill buy a book or w/e but if somebody has the formula for something like this, or can tell me what book its in, or anything like that, i would just use the measurements off of the 2nd gen irs, but its a different setup and i am modifying it to a multilink irs if you have been following the thread, at all, youll know what im talking about, i have access to a full chassis shop that can weld up all the adjustable chromoly controll link arms, and the housing around the pumpkin, and whatever else i'll need,

so if anyone can steer me towards this formula and get me out of this rut, theres a 1 million dollar reward, really!

not really but it would be a great help,

thanks
Paul

toxic_d

Autopaul, sorry for the delays I have not forgotten about you...

Here are a few helpful links
http://www.eng-tips.com/viewthread.c...=129475&page=1 A shirt discussion as to order of design importance.

http://www.susprog.com/susptype.htm A nice looking piece of software to help in the design phase.

http://www.eng-tips.com/faqs.cfm?fid=967 A few kinematic parameters that need to be considered and addressed.

I feel the software is you best bet to get the needed numbers but the other stuff there is just as important!!

Toxic_d

autopaul

hey thanks allot toxic d, that should help allot, ill get back to you about that million dollar prize,

but really i cant wait to start desinging this thing,
thanks
Paul

autopaul

ok update time, comon guys i want some valid opinnions,

so heres whats new, i am picking up a 2nd gen rear subframe tommorow, and im going to be making plans when i get it, ill be sure to take pics and post them as i go allong cause i definately want some input, im new to this stuff and many minds is better than just mine,... i still cant seem to find any formulas on how long to make theupper and lower controll arms, i think i may just copy the measurements off of another multilink irs unit, then go from there,

so thats my update, nothing realy new other than that, besides that somehow i got kicked out of the eng-tips forum, i dont even know what i did wrong, haha, oh well, so much for that,

thanks for your input and help but i still need allot of help before this dream becomes reality... things may be slow for this project as i have to go to school coming up soon, and im gonna need a second job, which leaves little time for the car... but hopefully my machining course will help me with the desinging and building aspect of this project.,, so any ideas and helpful suggestions are welcome

Paul