Porsche 944: Actually there is a substitute

[sparkydog]

Getting verrrrry close to finished with the prep work. The awning is functional. I just need to tweak a couple of more things and it will be off the list!

And the yard/driveway will soon be organized and more attractive. I was reaching my limit for visual mayhem.

I also finished fabricating two jack extensions (yes that sounds funny) so that I can get the 944 waaaay up off the ground. One is 8" and the other 16".

[sparkydog]

The 944 is high.
The Mustang is on the dolly and more stuff comes off every day.
Look what followed me home from the wrecking yard today.

[cAlvis165]

So your going with IRS? What is it from?

Chad

[aussiejohn]

Updates, please?????

Regards from Down Under.

aussiejohn

[Zoomin]

Hey man, sorry to hear about all that. Hope you get things turned around soon.

[67ChevyRedneck]

Probably be hard to find, but mustang Cobras came with IRS from 99-04. Supposedly the 03/04's are the best to use, would that work for you? Don't know if that would help or not...

[sparkydog]

Originally Posted by 67ChevyRedneck

Probably be hard to find, but mustang Cobras came with IRS from 99-04. Supposedly the 03/04's are the best to use, would that work for you? Don't know if that would help or not...

Yes good suggestion. The Cobra IRS or the Cobra straight axle would work very well for me. But the ones I have seen on Ebay and Craigslist are $1500-ish. For me that is big money. They are also a little too wide for the 944 body unless I was wanting to do some body mods. The 94-98 V8 rear was the perfect thing for me but I screwed the pooch and bought a V6 instead. The V8 would have had an 8.8 and now that I know how to read the damn tag on the diff I could have easily figured out if it was posi or not.

[sparkydog]

Oh yeah... Sparky's back in the ring to take another swing.

Welded some support into the Mustang's engine bay and then...
Whamo the Mustang lost it's nose. Guess I crossed the point of no return again!

[sparkydog]

Next I had to lower the 944 back down and get it on the dolly so I could spin it around. Then back up in the air. Then leveling it all up. Put "Righty" and "Lefty" the wheel locator gauges back on the sides of the 944. Then I tucked the Mustang's donor metal up under the Porsche and sat back for awhile (OK I sat back for a long while) and studied the situation.

[sparkydog]

Good news:
If all I had was 2D to fit the Mustang engine bay into the 944 I would be a lucky guy. From a bird's eye POV the graft will go well. The 944 and Mustang firewalls are almost at the exact same location. The Mustang inner fenders and strut towers give me more motor clearance yet fit inside the envelope of the 944's hood footprint. The Mustang and 944 floors are almost exactly the same height relative to the wheel CL.

More good news:
Even in 3D I have most of the issues going my way. As mentioned the floor heights are almost the same. The Mustang frame horns are approximately the same height as the 944. I think I am going to be able to keep enough of the 944 firewall and trans tunnel so that I may be able to re-use the 944's HVAC module. I think I will keep some of the 944 firewall and use the mouth of the 944's bell housing section of the fire wall but mod/replace the section just aft of the mouth so that there is more room for the GM tranny.

Bad news:
The Mustang strut towers are 3.5" taller (at stock ride height) than the 944. I was hoping to shoot the moon and do about a 1" body drop while I was at it so if I tried this too then the strut towers are 4-5" too tall to clear the 944 hood.

After 3 hrs of staring and schemeifications I have some ideas but before I belch them out - does anybody have suggestions on how I can get 4" out of the Mustang's strut length?

[sparkydog]

I also went back to the 6 X 944 guy's house and got my 944's rear suspension and brought it back to my chop shop. In my spare time I will study, measure and probably even render it in 3D CAD to see if there is a somewhat simple way to mate the Ford IRS spindles/brakes/axles/diff into the 944's swing arms. Here's a shot of the two rear ends trying to make nice with one another. (The Porsche engineers are probably rolling over in their graves.)

[hgs_notes]

While you're sitting there pondering, did you change to a fresh blade on the sawzall? Cause you're not done yet.

[hgs_notes]

Can you use the porsche strut in the mustang tower? It was made for a similar ride height but has shorter towers. Or are there other fords with shorter struts, like the focus or even other brands of car that have shorter struts? Just modify the mounting point on the towers to match the shorter strut style.

[sparkydog]

Originally Posted by hgs_notes

Can you use the porsche strut in the mustang tower? It was made for a similar ride height but has shorter towers. Or are there other fords with shorter struts, like the focus or even other brands of car that have shorter struts? Just modify the mounting point on the towers to match the shorter strut style.

Yes I am headed in a similar direction to what you said. The main choices I have are 1) shorter strut units that just bolt in, 2) modify a strut to change the location of its bracket on its body, 3) aftermarket drop spindles or 4) a combo of 2 or more of the other choices.

4" drop spindles would solve everything but I do not believe they exist for my model and if they do then the old economics thing comes up (they are expensive). I have been doing a little web research and I may be able to get most if not all of the 3-4" I want simply with another PN strut unit. I for sure can get 4" if I do a combo of using a different PN along with some slight mod to the strut mounting bracket. If I go this route I will first get a set of the new PN out of the wrecking yard and make sure it will really work, then buy a new set.

I will be proceeding with the graft of the Mustang engine bay metal over to the 944 bay. The stock Mustang struts and towers will come along and will initially be tacked into the 944 at correct ride height which will reveal the exact amount the struts are too tall. Once I have a workable solution to shorter struts I will figure out how to section (lower) the strut towers without messing up the suspension geometry.

[sparkydog]

First picture is what the stock Mustang strut looks like and has a catalog body length of 12.375".

Second picture is of a similar strut (not quite the same bracket) that I think I can make work. A version of this was used on the front of 2000+ Impala and Monte Carlos. It is approx 2" shorter and I can just shave off the coil perch. Another version of this is used on the front of early 2XXX LeSabre and DeVilles. It is even shorter and might give me a total of 4".

[67ChevyRedneck]

Does anyone sell a dropped one to lower the car (mustang)? Maybe for a racing application? 3.5" is a lot though... but it would be extra cool to include some GM parts instead

[sparkydog]

Originally Posted by 67ChevyRedneck

Does anyone sell a dropped one to lower the car (mustang)? Maybe for a racing application? 3.5" is a lot though... but it would be extra cool to include some GM parts instead

From the little bit of time I've spent on this the answer is yes there are 2" drop spindles in the aftermarket but they are for use with upper A arms not for the strut style like what I have. They are also about $800-$1000 for the pair.

[sparkydog]

Continuing to prep for engine bay surgery. The Mustang donor bay is a little leaner now. I drilled out the firewall panel spot welds and popped it off and have shaved off the upper fender "horns". This is about as much trimming as I will do for now.

The 944 can't be cut on until I can reinforce the nose and floorboard area so that it can survive the trauma of losing the firewall and most of the bay.

So I created an "exoskeleton" to help keep the fenders and grille area stationary. It is my sincere hope that this effort was total overkill and that I didn't need to do it. However should I accidentally kick or nudge the Porsche over the next few weeks I hope my weird cage will keep it all aligned. How do you like my high tech design drawings?

[hgs_notes]

Because of the geometry and strut mounting points I don't know how much shorter the strut would have to be. Such as a 2" shorter strut giving a drop of 3", similar to what you see by cutting front coils on our trucks. It's probably not a 1 to 1 ratio but you probably already considered this. You may be able to get what you want with a slightly shorter strut and by nipping the spring a bit or swapping the coils to a shorter stiffer set.

[sparkydog]

The top of the strut housing or tower or whatever you want to call the thing on the body that the strut bolts to is what needs to go lower by 3-4" in order for the Porsche hood to close. So I could hillbilly my solution by just sectioning the strut tower and dropping it and re-welding it. However the next problem would be that the (stock) strut would bottom out either at ride height or slightly compressed because the rod would be 3-4" deeper in it's travel.

Ride height is determined by the coil springs on a Mustang and the strut does two other things - dampen the springs and function as the upper pivot point of the spindles during turning. The location of the strut attach point also plays a part in the roll center and a bunch of other geometry stuff I barely understand. I would start out using the stock Mustang coil springs and cut coils or change springs as needed once the GM V8 is in. I would then buy a different PN strut so that it still has the correct travel in both directions but will fit into a tower that I shorten by 3-4". I will then have to carefully cut and re-weld the top of the strut tower (where the strut bolts to) so that it not only is lower in the engine bay but is also still on the same travel axis that it was before I cut it out. This should preserve the geometry. If I dork it up then caster, camber and roll center will all be screwed.

[hgs_notes]

Well done. One of those things you do "just in case" because it's much harder to go back and undo somethings.

I'm getting antsy to see that porsche firewall and engine bay cut out now.

[Jonboy]

Originally Posted by hgs_notes

Well done. One of those things you do "just in case" because it's much harder to go back and undo somethings.

I'm getting antsy to see that porsche firewall and engine bay cut out now.

The car looks scared of it with the headlights up, too.

[sparkydog]

Originally Posted by Zoomin

That's either very cool or very creepy.

Agreed! Even more creepy because the parts weren't for the 944 they were for other stuff. But either Google or the NSA probably owns Rock Auto by now.

Originally Posted by Jonboy

The car looks scared of it with the headlights up, too.

Now that's funny! I'll try to remember to put the 944 to sleep before I start cutting. When it wakes back up the bad stuff will be all over.

[sparkydog]

The final steps before surgery were to weld in some reinforcement to take the weight of the car and transfer it into my support stands without deforming the floor, or even worse - deforming the A pillars. Then it was on to marking out where my cuts would go. On the dirty sections where I was not able to use tape or a sharpie I used spray paint.

[sparkydog]

The surgery went well. The 944 was a little groggy afterwards.