you saw it here first...
before:
(http://i25.photobucket.com/albums/c73/gmby23/87%20turbocoupe/1a390d69.jpg)
after:
(http://i25.photobucket.com/albums/c73/gmby23/87%20turbocoupe/2405dc94.jpg)
(http://i25.photobucket.com/albums/c73/gmby23/87%20turbocoupe/cd1f32ed.jpg)
(http://i25.photobucket.com/albums/c73/gmby23/87%20turbocoupe/fd7273d4.jpg)
(http://i25.photobucket.com/albums/c73/gmby23/87%20turbocoupe/e1bf8571.jpg)
(http://i25.photobucket.com/albums/c73/gmby23/87%20turbocoupe/fcfa162e.jpg)
its not completely bolted in yet, but it is where it belongs. fits in the car with only minor tpuppies. i will attach the rear pickups thru the rear frame rails right where they sit.
i rechecked the rear axle centerline, and on the side i assembled it is 1/2" forward of stock. i still need to assemble the other side as well to check the centerline. since there was a 1/2" difference side to side in the stock rear axle centerline, the other side may be closer due to this side being the long side originally. unless it is skewed badly, im not goin to worry about the change in wheelbase. as you can see in the wheel pics there is plenty of room in front of the wheel still.
Looks like it should fit in there pretty well. You're going to sleeve the bolts that go through the frame right?
I don't think it would be that difficult to move it back a touch either. You may want to anyway to avoid any odd issues with spring/shock mounting, since they are the 3/8-1/2" farther back in the car.
i guess i should have stated "at this point" im not gonna worry about it, hehehe. if i see any issues with parts alignment as it comes more together, then it will be a different story. movin it back will cause alot more issues with interference with the tank mounting. i already notched the right tank strap mount pad. the tank is offset. i am lookin into options for clearence there as well since the carrier hits the tank on the pass side.
im actually plannin on welding threaded spuds thru the rail. they are .75x4.25 chro-moly and accept 1/2x20 bolts. that way i can weld em on both sides of the rail, and jus thread bolts in rather than put a nut on the backside.
since your here, chuck...where is the length difference in the shock mounting? is the upper pickup further from the axle? wonderin if i will need to fab an upper mount to lower that point to make use of the cobra bilsteins i have. guess ill probly know as soon as i test fit a shock, hehehe
For this I would fab up something up top. Not sure of the overall difference in length of the IRS shocks vs the Tbird stuff though.
Cobra IRS?
sweet...nice job! saw this a couple years ago in a fox stang. mmff, or 5.0(dont remember wich) has a nice little article on this swap as well this month.
Is that thing as heavy as everyone makes it out to be?
i havent put one on a scale, but it is heavier than a live axle.
then there are arguments for sprung vs. un-sprung weight, etc.
then theres my justification....foxes are nose heavy anyhow.....its ballast :flame:
Nice ballast man...lol. Seriously though, that looks really good...I've been thinking about a Cobra IRS in one of our cars...not that I wanted to do it, but just wanted to see it done...my wish has come true..lol...good work man!
-Don
that thing is gonna handle like your floating on air man..
im definatly watching this car
well im hopin more for handling like its forcibley attached to the ground :D
that would be nice... those cobras hook real nice... but arent they just a wee bit heavier in the back than our foxes anyway?
i havent scaled my car yet, so im not sure where the birds are for balance.
the 00R i had on the scales was 3580lbs total and 56/44 split
Would there be any major benefit to doing this? I mean I have heard alot of cobra owners take this out to replace it with a solid axle due to wheel hop, more weight and broken half shafts. I have thought of doing this more than once but all I hear is bad things about the Cobra IRS. What are the pluses of doing this?
Would there be any major benefit to doing this? I mean I have heard alot of cobra owners take this out to replace it with a solid axle due to axle hop, less weight and broken half shafts. I have thought of doing this more than once but all I hear is bad things about the Cobra IRS. What are the pluses of doing this?
If you're looking for just a straightline car, then yeah the IRS is not ideal. That's why alot Cobra owner's swap it out....they spend all their time at the dragstrip.
Better ride and a more balanced handler are some plusses.
Out of the box, the Cobra set-up is a big bundle of compromises. With some mods it can be a decent performer, but still limited. Most of the bad stuff is related to how it had to be designed to fit in the Mustang chassis w/o mods (from a live axle) and to keep it soft enough for the tender asses of "most" Cobra buyers......
Cool you get a big :bowdown: . That is pretty cool.
Thats is one sweet setup you got going on there. Good luck to the out come.
I have always wanted to do this swap to my '85 Cougar, just never had the money to afford it. Glad to see I'm not the only one to be thinjking of this swap. Definatly keep us updated on this.:bowdown:
that is so nice! if i ever get another cougar i am so doing that
Alan
Any new updates???
I've been planning this for quite a while. Need some other work done first but I can get the whole rear for around a grand or less.
Here's a link to what got me thinkin' on this:
http://www.mouthbreather.net/IRSSWAP.HTML
I'd love to see how it all comes together for you
It all comes together very well, considering the rear end has been in his car for a while now.
DOH!!! I didn't look at the dates on the posts.
My bad.
I'll just shut up and go sit in the corner now.
Carry on.
so where are the new pics? and drive report? LOL
Well I've seen the car together. It looks nice.. great stance. The only driving that car is doing at the moment is on a tow dolly.
not really any updates other than the links in my progress thread. i know they are old, and they are probly what got this thread dug up....
the IRS portion is together and waitin on me to finish up the rest of the car.
Gumby,
Do you have the parking brakes working properly? Mine's giving me fits.
the factory TC cables are still in there, and reach the calipers fine on my setup.
i do not have them hooked up to the calipers themselves at this point b/c i think i have a frozen cable someplace in the system and i havent diagnosed that issue yet.
what kinda problems are you havin?
You've got an 87/88, right? I think those cables are longer than an 85's?
The rears seem to lock and won't release after engaging the parking brake. I tried to mimic the mustang configuration, by getting the cobra parking brake cables, moving the tbird pedal cable to the center of the car, and running a single cable between the two.
I've replaced the calipers with new, and still seems to be happening. grrrr.
I'm wondering if the MC is somehow responsible by not releasing pressure or something? I'll probably end up replacing it with a different unit. Talking with a guy from Baer, he was of the opinion that that one has too small a bore. I think the one I've got is an Al unit from a mid-90s Mustang. He suggested the "cheap, ugly one", whichever that is.
Thanks
yes my car is an 87, so my stock rear calipers use the same type of connection as the IRS calipers. if you dont care to back track some, there is good info on converting the drum parking brake system to discs in this (http://"http://www.foxtbirdcougarforums.com/showthread.php?t=13175") thread.
have you done any mods to the prop valve? that mustang MC isnt gonna like being used with rear discs either. check out http://www.sn95brakes.com/ for rear disc conversion info on prop valve and MC selection.
thank vishnu sn95 got rid of those freakin' popups.
thank you for the drum-to-disk conversion link, I was looking for that but couldn't remember where it was.
The FMS prop valve is installed and the (distribution?) block gutted. At this point it's a manual 2-port MC - no booster because I need room for the intake. Power brakes would be nice if someone has a booster that won't take up space like the factory ones.
I've also read these posts
http://corner-carvers.com/forums/showthread.php?t=28352&highlight=Anyone+run+Manual+Brakes+for+Autocross
http://corner-carvers.com/forums/showthread.php?t=4832&highlight=More+mustang+brakes...M-2300-K+vs+Baer+Track+kit...any+opinions%3F
At this point, everything's blurring together. TMI.
How much harder would it be 2 do this setup using an 8.8 irs outta the mn12 bird instead of stang? I have no idea where to look at prices or possibly gettin the cobra setup and thinking about ditching the 9 inch idea for this considering i prefer the irs handlin.
BIG waste of time. The two are not even comparable. The MN-12 would require alot more custom work to get it in the car and there is no support at all for it.
i was afraid of that.
So, to bring this thread back up again. I was reading this page:
http://www.mouthbreather.net/IRSSWAP.HTML
and it seems to say that all you need to do is line it up using the quad shock bolt holes, clearance a couple spots so the mounting bracket can get all the way up onto the frame rail and drill/bolt it on. Also make some brake lines and put the springs/shocks in. Is it really that easy? What has to be done for the driveshaft? And I think it was covered already, but what is the stock cobra IRS rear track width and did it change 99-02 and 03-04?
yup, its that easy......for a mustang
hahaha, I figured there was a catch with the 'birds. But can the back half of another 'fox' really be that different? I tried reading your thread for the other things that had to be done, but it was hard to follow without seeing it or maybe knowing more about the irs setup...
The IRS attaches to the car at the driveshaft, the rear pads (which attach to the frame rails), and the lower control arm points (torque boxes). To install, you'll need to pull just about everything related to the axle, drill a few holes, and sort out the brakes.
If you compare Gumby's experience to mine, it seems there some variation in the frame rails - not sure if that's by car, year, or other.
It's best if you have a place like a garage or secure driveway so you can leave the car on jackstands. After you pull the stock parts and diassemble the assembly, bolt in the stripped cradle at the front and test fit it. You can then pull the cradle, assemble the IRS, and install it.
With all your ducks in a row, it's possible to do the swap in one or two weekends
wow, that's crazy! So you're experience pretty much followed thath webiste? Did you end up with your rear-end 1/2" forward as well, or is this part of the frame discrepency?
no, skidoo had his IRS cradle stretched to match the tbird wheelbase; mine is not.
the same difference between mustang and tbird lower control arm length still applies to the IRS cradle due to its pick up location on the chassis.
oh, I see. I forgot about that difference. So beside that, what else is there that isn't as simple as just raising it up, drilling/sleeving the holes and bolting it in (basically, what else that isn't on the mentioned website)?
Maybe someone else will weigh in here, but you might want to consider welding the pads to the frame rails instead of bolting them.
If I were you, I'd test fit the cradle then decide if you want to mod the cradle or not.
What's not mentioned is the "little" stuff, like running brake lines, tank mount clearance, fuel lines etc.
oh yeah, but that stuff's fairly easy. The reason I'm asking about the 'unmentioned mods' is because I'm moving for a bit and will have very limited tools for a while. I'll have all my hand tools, impact, sawzall, drills, cheap/basic 80 amp mig welder, but no air tools. I'd want to retain the stock wheel base and I don't want to have to do any massive chassis modification (aside from the 'massaging' mentioned to get the pads to slide all the way up). So I'm trying to get all the details I possibly can to decide if I can pull it off where I'll be working on it...
Things I haven't mentioned specifically: driveshaft, master cylinder, prop valve plug, external adj prop valve. And I may remember something else.
ok, well I have an aluminum driveshaft waiting to be cut (will my stock or the crown vic interceptor bolt to the IRS?), already have 98 cobra brakes on all 4 corners with matching MC and porp valve so the system is setup up for the IRS brakes (are they different than the straight axle brakes?). let me know what else you think of. thanks
the companion on the IRS diff will depend on what year IRS you get. i got a 99 IRS with an 03 companion . i robbed the companion off my stock 8.8 for the IRS to reuse my stock d/s. either way you should already have the parts you need to make it work.
the calipers are the same, the rotors are 11.65" vented. you would be fine there too as far as the hydraulic part of your system being up to task.
cool, thanks
And I think it was mentioned already, but do you know the track width difference in the 03-04 IRS compared to a 96 straight axle (mustang)?
The 99-04 is about 1.5" wider overall.
so the 99+ IRS is wider than the stock mustang straight axle? dang, that throws off my plans...
No, even the 99-04 straight axle is wider....
Ok, so I'm confused. Basically, what I'm trying to figure out is if my setup:
Stock 88 TC 8.8 with 96 mustang axles/brakes
is wider/more narrow/same width as the 99-04 IRS...?
ALL the 99-04 stuff is wider than the 87-88TC or 94-98 8.8...
Ok, I get it. thanks
So, another question, how much do the bottom mount points on the cradle have to be stretched forward to retain the stock 88 thunderbird wheel base.
.75" .. maybe.
LOL... hmmm... Is the 'maybe' you're way of saying you're unsure? I'm sure I can find the difference between mustang and 'bird lower arms and use that amount.
so did you do the work yourself or take it to someone?
try checking this
http://www.cardomain.com/ride/2542616
"maybe" because there seems to be some variation in the way the IRS fits, your best bet is to test fit.
Dang, you really did a lot of ! Thanks man, this helps a lot! Hope you don't mind a few PM'd questions if I get this other car and start on the IRS...?
Gumby, what springs and shocks are you running? Is there a spring I can run with my fox mustangs shocks just to get by with the IRS until I get an MM coilover kit...
You will at the very least need Cobra IRS shocks...
i am runnin cobraR springs and bilsteins.
your live axle shock will not work with the IRS. the lower bolt is larger on the IRS control arm.
thanks, good to know... So the cobra r springs aren't too short?
short is a relative term....my ride height is very low compared to most guys car on here. :screwy:
im sittin at 25" ground to wheel opening over 245/45/17's(25.7" OD)
and I suppose there's no ride height adjusters for the IRS... I like low but I have to be able I get around town as well!
not that i have seen, but the spring is a 5.5" coil very similar to the generic springs most circle track guys run. so you can feasibly get any rate and free length you want from a race shop that sells coils.
well, at that rate I'll probably just aim for the coil overs straight away, especially since I'll be halfway there after buying the Bilsteins!
as you wish.
FWIW, the circle track springs are pretty inexpensive; added to the fact that i dont like the idea of single shear coilover mounts, and you see which direction i will be going
more info:
http://forums.corral.net/forums/showthread.php?t=969802&highlight=IRS%2A+springs
thanks gumby! I'll check this out after work...
either of you guys know how the ABS is setup on the IRS? for example, the solid axel has tone rings on the axels themselves, and then the abs sensor bolts to a bracket next to the ring... can you compare this to the IRS? I'm just trying to make sure the IRS I find to buy has all the necessary pieces so I can connect the ABS.
also, how hard is it to change IRS wheel bearing (compared to the stock original TC type front bearing)?
ABS tone ring on the IRS is located on the inside stub of each halfshaft. you can see it in this pic. the sensor bolts to the side of the differential case.
(http://i25.photobucket.com/albums/c73/gmby23/87%20turbocoupe/DSC00730.jpg)
IRS wheel bearings are sealed units, pressed into the upright.
they are sealed? huh. any idea how hard they are to change? Sounds like you need a press to do it...? upright; is that kinda the rear's equivalent of a spindle combine with the hub?
And one other question: do you guys know i the v6/gt brackets, calipers and rotors will work on the IRS. I know they are interchangeable on the solid axel but I was told they aren't on the IRS. Why? I ask because I already have the base brake setup and I found a great deal on an 03 IRS but is has no brakes...
The Cobras used vented rotors but the same calipers, with a thinner brake pad to take up the difference in the rotor thickness. The standard rotor on an SN95 is solid, unvented. They'd be a big step backwards, but that's not a problem because all you have to do is get the right rotors and matching pads. Everything I've ever seen says the calipers are the same.
Thanks, but I'm well aware of the differences. What I am asking is if anyone knows if the v6/GT brakes will physically bolt to the IRS assembly...
No...the mounting points for the brake brackets are on the rear uprights.
On the live axle cars, the mounting s that bolt to the axle housing are different between the V6/GT and Cobra set-ups.
You'd have to chop up the uprights to make the smaller brakes work.
Oh yeah, that makes sense. So basically, there aren't removable s on the IRS like we have on the live axels. So the s are built in... this means all I need is to get a pair of loaded calipers with brackets (for a cobra), a set of rotors and I should be ready to bolt it all together...?
The rear calipers will bolt on, but that's about it.
Any updates?
did you read the date on this? He has finished it.