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Am liking the fit of that one a little better.. :)

Re your warranty question.. I reckon its still good.. :)
 

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Discussion Starter #82
I wanted to get some measurements for the rear axle angles and things to see what I'd be dealing with from a 'stock' IRS setup and what I may have to do. I put on a wheel and tire from my WRX's summer setup even though I know the wheels I eventually use will be much wider and about 1" larger in diameter.
For the record, I've run gunmetal Advan RS wheels a long time before Factory Five put them on the Coupe R (over 5 years). Just sayin' ;)


Anyway... on to real matters at hand.
It seems the flanges on the frame or the A-arm spacing is off on my car too. I'm not sure if anyone else has it this bad, but for me it's just a small nuisance since I plan to make new A-arms, but I can see it being an issue otherwise. Hopefully this is something Factory Five is working on since I've seen other comments about it recently. I took out the forward bushing to make things fit for the mockup. You can see how far forward the arm is in the clevis:


For the axles, I wanted to see the stock angle and the angle they'd be if I ran with the diff raised up to meet the necessary transfer case height.
Here's a picture with roughly a 4" ride height (very slight axle pitch up):


And here's a picture with the wheel moved down to simulate the same ride height but the differential moved to match the transfer case flange (axle pitch down noticeably with the provided axles):

In reality, the upper A-arm was hitting the frame so I couldn't simulate the full angle

So... since I wanted to be wider in the rear anyway, I compared the Factory Five provided axles (bottom) with the stock 2015 Mustang GT axles (top). It's a 5" difference on each side.
 

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Discussion Starter #83
In transfer case to differential mounting news, I picked up a 30 spline pinion flange made for U-joints from a 03-04 Cobra that I'm going to see if it fits on the Super 8.8 pinion flange and in the 2015+ IRS case. In hindsight, I should have looked for a 2015+ F-150 pinion flange but I still may have to do that.


Here's how I plan to couple the transfer case output flange to the differential. The silver pinion flange will hopefully replace the stock IRS-to-CV-style-driveshaft pinion flange (black) used on the Mustang GT to let me move the transfer case further aft.
 

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Discussion Starter #84
Some progress and setbacks.

I was able to remove the 2015+ IRS differential pinion flange with the help of the Factory Five provided pinion flange to driveshaft adapter and a ratchet strap to keep it from spinning on my. I followed the instructions pulled from dhuff's Mustang GT repair manual. First I tried to measure the free spin torque of the flange which is under 20 in*lbs and then I removed the nut and flange itself with a puller. Not too difficult, but the procedure Ford uses is to punch the nut and stake it into a recess in the pinion gear. Great for holding it place from spinning, not so great to undo.


Next, I tried installing the 03-04 Cobra flange on the new Super 8.8 differential and found it's a no-go from stock part to stock part. Can you see the reason?




Ok, neither could I. After measuring with some calipers, I found the spline diameter is just about .030" smaller on the Cobra flange even though both are 30 spline 8.8" pinion flanges. Dang it!

I put out a request to Nitro Gear and they won't do a Cobra flange with a 2015+ Mustang GT spline even though they have the tooling to do both. I've also got a request in at a local company to see if they can modify the splines. I really would prefer not to have to modify the splines myself.

Any ideas of places I can contact to make the correct splines even if I have to turn my own flange on a lathe? Even better, a company that might be willing to modify the existing splines?
 

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You might try the Dutchman out of Portland, OR. Dutchmanaxles.com. When I was big into wheeling (rock crawling) he made some custom axles for me. You might check him out.

Sent from my SM-G950U using Tapatalk
 

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Discussion Starter #86
@TMScrogins, thanks for the info! You'll see below I made a new discovery, but I was looking for a place that would do custom axles so that solves a future problem.


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Well, you know what you say about the internet... you can't believe everything you read!

I realize these last few posts are a sidebar or tangent from the usual build, but what I'm finding is interesting nonetheless. Who knew that so many places list different spline counts for the same differentials? Or that the 2015+ Mustang GT and 2015+ F150 ring and pinions are interchangeable if you don't have any towing package that bumps the axle up to a 9.75" ring and pinion? Or that even truck guys on forums don't know what size differential they actually have because they only think of the number of bolts matters (now some realize that was an easy identifier in the past)?

Anyway, I stopped by a local spline and gear manufacturing business that turns out splines and hobs some Boeing parts. They confirmed that the spline pattern should be a standard 24/48 involute profile which got me thinking. What kept bugging me was that with a given diametrical pitch and pressure angle, you can't just increase the diameter without increasing the spline count. Well, that made me recount the splines on the Mustang GT stock pinion and flange. I thought I mis-counted because I read 30 spline everywhere, but there are 31 splines now!
Long story short, I ordered a 2015+ F150, 31 spline flange that seems to fit both the Super 8.8" and 9.75" differentials. Once that arrives, I can confirm.

 

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Discussion Starter #87
More silly transfer case and differential info below. You've been warned.

Good news! The 2015+ F150 flange for the 8.8 and 9.75" diff has the same spline count, same spline diameter and outer diameter (to match the oil seal), and same depth that's inserted. I was able to put the new flange on but didn't tighten it down all the way to get the correct preload. I'm going to pull it back off and check to see if the pinion nut sits at the same height because the white dust shield didn't fully seat when the nut torque started getting high. Worse case I add a washer under the nut to get everything to fully seat.

Even though the new flange pushes back the mating surface by almost 2", the pinion threads and nut stick out to eat up about an inch of that difference. Note to anyone who needs a longer driveshaft due to transmission choices or driveline angle issues and is ok ditching the Factory Five provided flange adapter, this could buy something like 2.5".



I cut the bottom X bracing in the Coupe's frame to drop the transfer case forward output flange right to the bottom of the frame line to get it as far down as possible without hanging down to get hit. With the new flange on the rear differential, I put the seat back in to get an idea of the new position. While not optimal yet, it is noticeably better than before. You can also see how high all of the driveline will sit relative to my seat. This will get reinforced frame members around it for sure so I don't break my hip if anything ever went wrong.



The final two pictures show the height difference again but also show that the seat belt bracket for the driver's right side lower tab will need moved or the other flange on the transfer case cut off. My guess is both.





Anyone want to sponsor the car so I can fund the transmission purchase in the near future and keep forging on, or get some wide wheels in a square setup, or rear Wilwood brake kit, or other necessary build parts? Pretty please? ;)
 

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Discussion Starter #88
Pretty pictures and charts time (because I don't get enough of that at work haha)

On a topic that can have infinite discussion with no resolution (also an aspect of work at times), I've decided to try to pin down what I want to do with the transmission gear ratios and final drive ratios. I chose a front differential to match the 3.73 of the Mustang GT performance pack to minimize upfront costs and I would like a fairly good spread of ratios, a 1st gear I can crawl in traffic with (Seattle to Everett), and a top gear I can cruise if the highways are open or take a run further away should I actually start traveling again.

I cropped all the captures the same so anyone should be able to save the charts to your computer and tab back and forth to see the changes more easily.

Baseline: 2016 Mustang GT, stock wheels and tires, performance pack


Second: Gen 3 Coupe, T-56/TR-6060, 3.73 rear, with 2.97 1st, .63 6th, square 295/35/18

Not too bad at all. I'm also trying to keep in mind that I want my engine to rev to 8000+

Third: Comparison to my WRX with a 07 STI 6-speed, stock tire size for chart

You can see 4th to 5th is a small change, 60mph already spins the engine at 2200rpm, and at 75mph I sit at 2750rpm.

Search for all available differential gears that match both the Super 8.8 and the 7.562" front differential I'm starting with to keep the size down...4.56:1's are available!
Fourth: Gen 3 Coupe, T-56/TR-6060 with 4.56 rear, 2.97 1st, .63 6th, square 295/35/18

Surprisingly, this is nearly identical to the crank to mph gearing of the STI I'm used to. Crazy, huh?

Finally, fifth: A fun thought should I change out 5th and 6th to .74 and .50 with the 4.56 differentials, square 295/35/18

I can crawl in stop and go traffic, shift similarly to my 390+hp WRX, and still cruise at 60mph like a stock Mustang GT at 1800rpm. Seems like that's full of hypothetical win!
 

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Beyond the choice between acceleration and top speed, isnt the real issue with gearing the balance between available power and traction for V max, or 1/4 mile time or 0-60.. etc.

That said 3.73 does get these cars to boogy very nicely off the line.. :) Into the 4's for final drive gearing is definitely not required with the power / weight and in your case.. 4wd traction... unless you primary goal is 0-60.

I picked 3.55 with an LSD for a street to track set up with softer springs and adjustable QA1's to compensate as required. Given the option again, as these cars cant really be made into a GT, I would have gone 3.73.

Loving your work, look forward to your updates and a sponsor coming onboard.. :)

Cheers

Chris
 

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Discussion Starter #90
As I wrote on the other forum... a sponsor would be awesome, I just have to figure out how to find one and then convince them the ideas in my head are worth their money or products. Sooo... until I have a great finished car, I'm guessing I'll be completely self funded haha!

I created what's below based on your comments about power vs. traction vs. speed, etc. It got me thinking (in a good way) about what all the differences would be. All that figured out based on my current logging and road dyno for the WRX and I have a bigger turbo ready to go on once I have this driveable.

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In other news, I half convinced myself I need the 4.56 gears. I know the Coupe is going to be lighter than my WRX, but I created a graph of it's current wheel torque vs speed and compared it to the natural aspirated build I'm doing. I can see why the WRX/STI/Evo all feel so fast from the get-go since they're usually not traction limited and the gearing is so low. With my current turbo and tune, it's got a pretty noticeable peak starting from a 5mph roll, but once it gets going, boy does it move quick. The 3.73 gearing of the Coupe, since I also hope not to be traction limited, would be great after 40 but seem slower on the butt-dyno until then just due to the gearing.

Here's the chart, based on wheel torques of my WRX vs. the wheel torque of a stock Mustang GT which I should exceed easily with my tuning, the better heads, non-restrictive exhaust, etc.


While waiting on building funds for the transmission, I'll start working on the updated rear suspension design. I'll post as I get that started to be sorted out.
 

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IMHO, I always thought the higher the HP, and lighter the vehicle, the less gear (lower numerically) you need. Also the less gears you need to attain higher speeds. Multiple gears are mainly for fuel economy.
Example 2000+hp Racecars user 2 gear powerglides with numerically low gears, and 10,000hp dragsters have no gears, direct drive slip.

Heavy vehicles with low horsepower need higher gear ratios and many gears to multiply the torque and get moving.
Example 18 wheelers, dump trucks etc.
 

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Discussion Starter #92
I realize it's been a long time without an update, but I've also been trying to clear out things in the garage and wrap up other projects at the same time.

I did a spur of the moment search on Craigslist for the tire size I wanted and a set popped up from someone with a drift car who couldn't fit the tires in the wheel wells. Worked out for me, because I got all four 295/40/18 Nitto NT555 G2's for less than the cost of two.
I also made use of eBay's recent pre-spring 20% off code for a purchase from a US company to get some wheels. Turns out one vendor was also having a sale at the same time and the cost of the wheels dropped dramatically with the stacked discounts. Add in that they upgraded to a nicer set when their inventory list had an error and I ended up a happy camper! 18x10.5 ET22, square setup in anticipation of the AWD working out.



As a result, this also means that I expect to sell the 18" Halibrand style set I got when I placed my order for the Coupe. With AWD, trying to match front and rear tire diameters with different widths and not being able to rotate them means it's unlikely I'll ever use them. If anyone is interested, let me know or I'll be posting it up in the classified section at some point.
 

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Discussion Starter #93
Figured I was past due for an update. I'm working on a mix of the theoretical and the practical by focusing on the rear suspension changes required to lift the rear differential up to a height that matches the transfer case output flange and have everything above the bottom of the frame.

First up was 'compensating' for the height increase by trying out the Mustang GT axles (which I showed earlier being 5" longer each side). I figured if I'm to re-do some of the suspension that I might as well lower the CV angles and one easy way to do that is widen the rear track. Who said we'd need spacers to get rid of the wheel gap? ;)



This also means I'll get to try out some fiberglass molding again. Weee!
Here's a side view that also includes the front differential I had to open up to verify the internals. For anyone who cares, the Ford Explorer and Ranger in the early 2000's used Dana 35 internals with a Ford requested case. Many places report the smaller Dana 30 only. Anyway, the body will need to be a bit wider when all is done.


Finally, I've been contemplating ideas on how to grab all the dimensions I want from the rear spindles as well as possible ones I want to use in the front. After chatting with some coworkers, one strong front runner (that didn't include using a laser scanner or FaroArm which require permission and a business case at work) was to use a center finder combined with a DRO on my mill. Since I don't have a DRO and I wanted to get started right away, a much lower tech solution filled in to get rough dimensions.
Check out my overturned book shelf and a combination square ruler!


I'll pull some dimensions from the existing frame and A-arms to get the nominal caster / camber / effective spring and wheel rates as a baseline and then design new geometry with those in mind. I'm still debating the 'easy' direct coil-over setup or a pushrod and bellcrank design. Hopefully more on that on or before next weekend.
 

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Discussion Starter #95
Thanks John! There are tons of awesome builds on here but I'm going far enough astray few things are relevant to most builds. Unless you mean another standard of crazy :)

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I made some really good progress doing a few coordinate transformations to get the spindles in the correct locations and match up with the 'baseline' Coupe rear suspension. Everything is at least really close without disassembling all the components to verify individually.

The top is the as-designed-by-Factory-Five layout.
The middle is the wider version using the Mustang GT axles, raising the diff to match the rest of the custom drivetrain, and using the same chassis mounting locations for the a-arms by effectively extending their span. I also assumed using the upper spring mounting location for a bellcrank to make things easier. Easier always being relative...
Bottom is the overlay of the two.


Initial findings:
1/2. I have an error on the spindle face location for my setup, it needs pulled inboard some (too wide of track)
1. The axle angle shouldn't be an issue
2. The angles between the a-arms and the axles is going to cause the axle CV's to probably bottom out because as the car compresses in height (bumps, any aero, cornering, etc), the arms and axles are not close to parallel.
3. The upper spring mounting locations may actually work well for a good rising-rate spring setup and if I get fully adjustable dampers they can up and easy to access without crawling under the car
4. I haven't looked at wheel rates, stock suspension travel estimates, or anything else yet.

Fun times ahead!
 

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Discussion Starter #96
Big milestone started/accomplished today: I placed the order for the transmission which is the last major component necessary!

I don't remember if I mentioned it earlier, but this will be a Corvette based T56 case with upgraded TR6060 internals, blueprinted assembly, and an adapter to bolt to the transfer case. It has to be a forward shift location instead of a mid-shift or tail shift. George Kreppein from Rockland Standard Gear will be building the unit for me and also works on the Tranzilla version of the T56.



Once everything is built, shipped, and delivered, I'll be able to get to work on finalizing the powertrain and make some real progress!!
 

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Discussion Starter #97 (Edited)
While the transmission is still a work in progress and RS Gear is waiting for Tremec to send them some additional gearsets to give the ratios I requested, I went looking to see what I might do for the interior and alternatives to the Kirkey seats that might still allow the even more restrictive space of the wider tunnel and fit my tall and skinny frame.

I lucked out an found a discounted, yet brand new and genuine Bride Gias II seat. I point out genuine because there are replicas all over the place with varying quality standards in the fabrics and stitching and unknown internals. From my reading, some are fine to sit in, some wear out quickly, some look poor on arrival, and none are crash tested. You can get a pair of replicas for half the cost of a single genuine seat. It may be the 'sport' model aka least expensive model of that line, but the only difference is the internal frame is heavier and the back is a metallic painted fiberglass instead of the usual but more expensive Kevlar. It's based on a FIA certified model but has a recline ability. The 'Low Max' setup puts the top of the cushion only about 1.5" off of the very bottom of the seat.

Here it is in the car testing out the recline:


Here is the side by side comparison to the Factory Five option of the Kirkey high-back seats:
 

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Those are really nice seats. I looked at them too, but unfortunately with the gen 2 coupe I didn't think they would fit.
Did you only get the one?

John
 

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Discussion Starter #99
Those are really nice seats. I looked at them too, but unfortunately with the gen 2 coupe I didn't think they would fit.
Did you only get the one?

John
I only bought one to start due to the expense and being unable to sit in it and fit it in the car beforehand. I didn't want to have to find a way to sell two in case they didn't fit because I was worried I'd lose out on a bunch of money finding someone that wanted a pair for $$$.

I might get a fixed bucket Bride seat like the Vios or Zieg for the passenger side since I should be able to find a matching one that is both wider and less expensive.
 
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