Ford Super 8.8 irs swap thread. Rear brakes too

[Invincibleextremes]

Had my brother make me a donut that had the r200 flange bore inside and the mustang super 8.8 other bore...  then I messed up one set of holes, but the second set perfect.  So I'll be driving soon on this setup without having to buy another driveshaft just yet.

[neruve]

What kind of price are you thinking for the knuckles and cradle when you are finished prototyping?

[Invincibleextremes]

On 5/24/2018 at 7:50 AM, neruve said:

What kind of price are you thinking for the knuckles and cradle when you are finished prototyping?

Well here's what I'm thinking, if I get all the bits, laser cut, tack them together using a jig I'll built so each piece is the same, and then have them professionally welded (Not by me)  I'm looking at around 200 per upright and ballpark 500 for a complete cradle set up to use the factory 2015 mustang bushings.

 

Now, but I can probably do drastically better than that for just a tacked together setup for the guys who trust their own welding...  or want to have them welded by a friend of theirs etc.  I can tack it all up in the jig and ship it out.

 

Not 100% sure yet as I'm not sure on the amount of work it'll take, and the expenses of producing it all, but that's the idea.

[neruve]

1 hour ago, Invincibleextremes said:

Well here's what I'm thinking, if I get all the bits, laser cut, tack them together using a jig I'll built so each piece is the same, and then have them professionally welded (Not by me)  I'm looking at around 200 per upright and ballpark 500 for a complete cradle set up to use the factory 2015 mustang bushings.

 

Now, but I can probably do drastically better than that for just a tacked together setup for the guys who trust their own welding...  or want to have them welded by a friend of theirs etc.  I can tack it all up in the jig and ship it out.

 

Not 100% sure yet as I'm not sure on the amount of work it'll take, and the expenses of producing it all, but that's the idea.

Well, mad props to you for trying to keep it affordable! The tacked kit would be awesome for your budget people like myself. I have several friends with TIGs. I'll definitely keep my eye on this thread. What are you using for the front setup. I have often though about just putting an SN95 strut/spindle in the front for 13" corbra brakes cheap. Just haven't gotten around to doing it yet.

[Invincibleextremes]

10 hours ago, neruve said:

Well, mad props to you for trying to keep it affordable! The tacked kit would be awesome for your budget people like myself. I have several friends with TIGs. I'll definitely keep my eye on this thread. What are you using for the front setup. I have often though about just putting an SN95 strut/spindle in the front for 13" corbra brakes cheap. Just haven't gotten around to doing it yet.

I have a thread in the braking forum about the front, but I'm using 2014 mustang spindles mounted on 2004 srt4 coilovers...

 

The srt4 coilovers are being used front and back, and the 2014 mustang brakes are being used front and back, and the diff hubs and axles are 2015 mustang.

 

I'm sure guys like you really appreciate the systems being complete off one car, not mismatched like prior offerings using custom struts and other budget blowing things.

[clarkspeed]

I like your approach. Very interesting selection of parts. I also looked at using the Mustang stuff, but never got around to test fitting parts. 

[Invincibleextremes]

6 minutes ago, clarkspeed said:

I like your approach. Very interesting selection of parts. I also looked at using the Mustang stuff, but never got around to test fitting parts. 

Just doing what I can. I spent today trying to get my hands on a z32 turbo stub axle so I can compare the 2015 mustang splined.  Both the 2015 mustang and the z32 turbo are 32 spline 22.8 mm on the bolt on cv splines outside.  Just don't know if they work together without getting my hands on one.

 

The 2000 dodge intrepid is the same bore in the backing plate, so you could use that too if you wanted to go bigger with 33 spline cv axle ends that go into 28 spline 930 shafts via the f150 front cv... But you'd be splitting hairs at that point, as getting custom 2,000 hp 2015 mustang axles isn't that expensive for how strong they are...

[mtnickel]

Did you look into the effects on the scrub radius of using the front knuckles?

 

Also, wonder if we could also figure out just a diff swap option:

1) use the cradle you're making

2) Perhaps we could have mustang axle just shortened and resplined on one end for the 930 CV. Then 930 to stock stock datsun companions are readily available.

https://zcardepot.com/billet-aluminum-axle-adaptors-930-cv-240z-260z-280z.html

3) Driveshaft adapter as you've shown.

 

[Invincibleextremes]

11 minutes ago, mtnickel said:

Did you look into the effects on the scrub radius of using the front knuckles?

 

Also, wonder if we could also figure out just a diff swap option:

1) use the cradle you're making

2) Perhaps we could have mustang axle just shortened and resplined on one end for the 930 CV. Then 930 to stock stock datsun companions are readily available.

https://zcardepot.com/billet-aluminum-axle-adaptors-930-cv-240z-260z-280z.html

3) Driveshaft adapter as you've shown.

 

Front geometry stays stock aside from it being a 2 inch drop, which helps with the bump steer.  But requires a wider rack to completely do away with bump steer... Which opens up the possibility of using a wrx rack which is near bolt on anyway.

 

Yeah, is is very possible to use just the cradle and either use techno toy tuning uprights with z32 hubs and brakes, or 240sx hubs and brakes tonstay 4 lug or anything else along those lines.

 

But you would be shooting yourself in the foot at that that point...

The use of cv axles for $75 each and getting them cut down at $75 each and then using 2014 mustang brakes at $150 or less and paying $150 for some 2015 bolt on hubs is the cheaper, stronger way to go....

 

Not to mention srt4 struts are $80 each brand new, and springs are $40 a piece to set them up for whatever weight and balance your car happens to be...

 

Like I said, you could do a lot of things, no reason you couldnt, just have to decide on what you want and how much it will all cost you.

[mtnickel]

True enough. Going to all the work, may as well gain all the other benefits for not much more. 

 

So the ackerman is the same too? Interesting considering the different wheel base. Steering ratio not changed either (ie steering arm is same length?)

[Invincibleextremes]

3 hours ago, mtnickel said:

True enough. Going to all the work, may as well gain all the other benefits for not much more. 

 

So the ackerman is the same too? Interesting considering the different wheel base. Steering ratio not changed either (ie steering arm is same length?)

The wheel base is the same, both front and rear, and side to side, so I'm not quite sure as to what you are asking.  The reason my wheels stick out so much is that they are wide...

 

You could stay with 17x8 inch wheels and stay withen stock fenders, I just chose not to.  I've always wanted a widebody Z, and built it with 11 inch wide wheels.

 

So the scrub radius, and the Ackerman remain the same as a 240z at factory ride height, unless you choose to change it with really wide wheels, but that is no different than a stock 240z on fat wheels.

Edited May 29, 2018 by Invincibleextremes

[mtnickel]

3 minutes ago, Invincibleextremes said:

The wheel base is the same, both front and rear, and side to side, so I'm not quite sure as to what you are asking.  The reason my wheels stick out so much is that they are wide...

 

You could stay with 17x8 inch wheels and stay withen stock fenders, I just chose not to.  I've always wanted a widebody Z, and built it with 11 inch wide wheels.

 

So the scrub radius, and the Ackerman remain the same as a 240z at factory ride height, unless you choose to change it with really wide wheels, but that is no different than a stock 240z on fat wheels.

I wasn't talking about track width.

The mustang has a wheel base (distance from front wheels to back) of 107.1"

The 240z has a wheelbase of 90.7".

The ackerman usually changes depending on the wheelbase. It might be a little off...but perhaps won't be an issue for most driving situations, but could cause an increase in scrubbing in low speed parking lot maneuvers and tighter low speed corners.

[mtnickel]

Ah, I failed to remember that track width has also decreased, so if the track width and wheelbase descrease at close to the same amount, then the ackerman probably is pretty close. My bad. But good food for thought!

[Invincibleextremes]

3 minutes ago, mtnickel said:

I wasn't talking about track width.

The mustang has a wheel base (distance from front wheels to back) of 107.1"

The 240z has a wheelbase of 90.7".

The ackerman usually changes depending on the wheelbase. It might be a little off...but perhaps won't be an issue for most driving situations, but could cause an increase in scrubbing in low speed parking lot maneuvers and tighter low speed corners.

Reason the Ackerman remains the same is that the mustang spindles have the same ball joint to tie rod distance as the 240z...  But the tie rod is outboard by a little bit, so using a rack with a wider pivot center Like the wrx then brings this back to stock 240z geometry.

[mtnickel]

2 minutes ago, Invincibleextremes said:

Reason the Ackerman remains the same is that the mustang spindles have the same ball joint to tie rod distance as the 240z...  But the tie rod is outboard by a little bit, so using a rack with a wider pivot center Like the wrx then brings this back to stock 240z geometry.

I was under the impression ackerman is based not on the distance from ball joint to tie rod, but rather the angle between the spindle (wheel axis) and steering arm.

Additionally, to correct bump steering it's the inner pivot (ie inner control arm mount point) that has to match the inner tie rod joint. The outboard tie rod mount will mainly dictate how long of a tie rod you need.

[Invincibleextremes]

1 minute ago, mtnickel said:

I was under the impression ackerman is based not on the distance from ball joint to tie rod, but rather the angle between the spindle (wheel axis) and steering arm.

Additionally, to correct bump steering it's the inner pivot (ie inner control arm mount point) that has to match the inner tie rod joint. The outboard tie rod mount will mainly dictate how long of a tie rod you need.

That's what I'm trying to say.  The 240z rack has an inner tie rod pivot width of 610mm and the wrx is 650mm. Therefore using s80 Volvo inners and 240z techno toy outers will bring the OUTER tie rod width to where you need them, but it's the inner tie rod distance being increased that will bring the angles back to very close to stock.

[mtnickel]

makes sense. 

These are, I believe, the different ways Ackerman changes. But as I said before, since wheelbase and track width are both decreasing, then Ackerman is Probably still in a reasonable range.

[jpndave]

1 hour ago, mtnickel said:

makes sense. 

These are, I believe, the different ways Ackerman changes. But as I said before, since wheelbase and track width are both decreasing, then Ackerman is Probably still in a reasonable range.

 

That's a good hand drawn summary "perfect Ackerman" on top and both extremes in two dimensions. With the ackerman aligned with the center of the rear "axle" or centered between the rear wheels, inner and outer tires turn with zero scrub ie they turn in the radius that each travels inner tighter than outer. That's the theory a line through the pivot point for the wheel and the tie rod end pivot center. Things can also change as all this gets dynamic rather than static or theoretical and the struts don't hold everything perfect as suspension cycles. These old cars flex a bit too. I haven't run the numbers on stock or even started design for my car but it definitely will be in the considerations. You've got scrub radius, as well as the caster and camber to deal with too. Lots going on up there.

[jpndave]

1 hour ago, mtnickel said:

I was under the impression ackerman is based not on the distance from ball joint to tie rod, but rather the angle between the spindle (wheel axis) and steering arm.

Additionally, to correct bump steering it's the inner pivot (ie inner control arm mount point) that has to match the inner tie rod joint. The outboard tie rod mount will mainly dictate how long of a tie rod you need.

 

All these rods and points might not be the same length or location but have to move in the same arc and planes as the suspension. If not, then the effective lengths change as things move and bump steer happens. Again, it's all in a 3 dimensional world and the steering has to stay constant in relation to the wheel/knuckle as all of this moves or you toe in or out depending on what each wheel is doing. The double wishbone is easier to control more exactly but a strut is easier to package and cheaper with acceptable changes.

 

There are a couple of really good books on the subject of suspension and some threads out there that are helpful. I'll have to go look at my library and post a few up. Properly designing the rear is one thing but throw steering in the mix and it gets all sorts of complicated.

 

[Invincibleextremes]

6 minutes ago, jpndave said:

 

All these rods and points might not be the same length or location but have to move in the same arc and planes as the suspension. If not, then the effective lengths change as things move and bump steer happens. Again, it's all in a 3 dimensional world and the steering has to stay constant in relation to the wheel/knuckle as all of this moves or you toe in or out depending on what each wheel is doing. The double wishbone is easier to control more exactly but a strut is easier to package and cheaper with acceptable changes.

 

There are a couple of really good books on the subject of suspension and some threads out there that are helpful. I'll have to go look at my library and post a few up. Properly designing the rear is one thing but throw steering in the mix and it gets all sorts of complicated.

 

Agreed.

 

I find it ironic that my 1st gen mustangs, and my firebird, and my 69 charger all have double wishbone, and my only car known for handling (although my 68 firebird is no slouch in that dept) has a strut.

 

In fact, I find it downright amusing that most modern cars are strut based.

Edited May 29, 2018 by Invincibleextremes
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