jdm65's JDM-inspired Gen3 Coupe Build

[jdm65]

Lets gooooooo engine is in, all brake lines are ran and mounted, caliper setup is complete, pedalbox is welded in, in theory I could roll the car down a hill and it would stop and steer!




Why I decided to build a Factory Five, and who am I?

My interest has always been with JDM stuff, but sometime in highschool, one of my best friend's father built a Factory Five '33 Hot Rod with a Gen1 Coyote. That car was SO cool, that I started to dive really deep into the super rich American car culture. My first time seeing the Coupe was actually on Factory Five's website - I didn't even know anything about Cobras! Over the next few years dipping in and out of school and life, my dream Factory Five flipped from the 818C, to the GTM, back to a Cobra, but ultimately I settled on the Coupe. Fastfoward to today, sometime in December of 2020, I decided that, if there was any time to build the car, it would be now.

I'm a freelance artist running a vinyl shop - so I'll probably end up drawing my Coupe at some point... but I've decided to save that for AFTER I finish the car hahah


So, what am I building?

As an artist by trade and a JDM guy at heart, my plan for the car mostly revolves around the aesthetics of the car rather than the performance - which isn't to say it'll be slow, I don't think ANY Factory Five can be slow considering the usual powerplant offerings and the sheer minimal weight of EVERY F5 car haha... That being said... this is my first experience with anything American, and I wanted something special. So whatever results from this project will hopefully reflect my experiences building Japanese cars and a new interest in stuff from this side of the pond!

At first when I pulled the trigger on the kit back in December, I just wanted to experience something American for the first time - so I had pretty simple plans for the car. I wanted a Coyote-powered coupe, and some cool Japanese wheels, but aside from that I didn't have a lot of other plans.

But I guess in the months in between I kinda let my mind run wild with the car and here we are haha!

Around the beginning of the 1980s in Japan, tuning culture, especially top speed racing, was exploding in popularity in Japan. The best drivers and the most well-known tuners would drive what's known as the Tomei Expressway in everything from Datsun Z cars to imported Panteras. It's actually a really interesting history to what is essentially the beginning of the Japanese car tuning craze - lots of the drivers and tuners went on to open some of the best-known tuning companies today out of Japan like Trust, HKS, and Top Secret.

Here's an awesome photo of Trust founder Mr Okawa in his '71 Trans Am racing a privateer's Pantera at the Yatabe High Speed Test Track!



So, what am I building? A JDM inspired Coupe! A Coupe that would look perfectly in place alongside those Japanese-tuned American cars of the 80s and 90s.


Here's the shortlist...

Gen 3 IRS Complete Kit
3.73 Torsen diff
Gen1 F150 Coyote with custom BMW ITBs, Boss 302 Cams, managed by a Link G4+ Thunder
Tremec TKX
Cadillac ATS 4-piston Brembos, stock S550 PP1 rear brakes (vented!)
Volk Racing TE37V Mark II, 18x11 -7 front, 18x11 -33 rear


A few custom things that are a little less traditional...

Air cup suspension (retains regular spring+shock for regular driving, but can be raised 2-3" when needed)
BRIDE Zieg III Bucket Seats
STACK digital instrument cluster
Assisted electric power steering, controlled via the Link G4+ to only be active under 15 kph.
Full 10-step traction control
Again, the ITB'd Coyote, with velocity stacks off an AE86 Corolla

Body wise, I'm not planning to do anything radical with the Coupe shape, I honestly think it's one of the prettiest shapes to come out of the 60's and 70's. But I do want to add my personality to it, so the current plan is solid color, no stripes, and a shakotan-style slit spoiler under the cam tail. I'd like to do some kind of airdam as well, but I'm going to focus on getting the car together so I don't get caught up on lengthy custom projects. I could have gotten the Coupe-R airdam, but I don't think I actually can due to the ride height of my car haha.


The Drivetrain

Early on into the build I had MUCH more budget oriented plans which revolved around an SBC with quad webers (I'm so sorry!!) but thankfully a friend talked some sense into me, and with the fortunate timing of a low mileage Gen1 F150 Coyote showing up on FB Marketplace, I pulled the trigger to the correct side!

I know some people are looking into the F150 swap as it's much cheaper, so I'd like to share what I've found:

The main differences are as follows:

Intake

The intake is different than on the Mustang Coyotes across all three generations. It's got longer runners which are optimized for better bottom end torque. No problem, either run it or swap for a very cheap 2018+ intake.

Firing Order

The Gen1 F150 Coyote and Mustang Coyote use the same firing order, however, the Gen2 and Gen3 F150 Coyotes use a different firing order.

Oil Pump

The F150 Coyote uses a smaller oil pump. It's not possible to just replace the gears (afaik) as the housing is different, so a complete Mustang pump is needed! I've been told the F150 timing cover will fit over the mustang pump fine (it's different) but I haven't confirmed this yet. I'm just gonna do it and find out, haha

Compression

This is slightly more significant to me, the Gen1 F150 Coyote has a 10.5:1 compression compared to the Mustangs 11:1. This has been changed with the Gen2 and Gen3, and both the F150 Coyote and Mustang coyote are now 12:1 comp

Cams

The F150 uses a different intake cam, not sure if the exhaust is different, but probably!

Other Differences

The F150 tune is optimized for towing and low end torque, whereas the Mustang is optimized for performance. Also the F150 Coyote has an oil cooler that apparently will not clear on the Gen3 Coupe.


What I've done to mitigate these differences:
So seeing as the Coyote's weakest point is apparently the powdered metal oil pump, I've decided to just replace the whole F150 oil pump with a billet gear replaced unit from Boundary Racing Pumps. As for the cams, I've got a set of Boss 302 cams I'll be using instead, and the entire intake I've replaced with my custom BMW ITB setup. The differences in the tune are also irrelevant to me, as I'm using a standalone ECU. I'm leaving the compression as is, and I don't have to mess with the firing order as I have a Gen1 Coyote. As for the front timing cover, I cannot recall which builder documented this, but he just used the F150 timing cover and alternator and called it a day, which is what I'm also planning to do.

All in, I'm rolling into this setup at around $9k CAD (around $6500 USD), which is under what a crate Coyote goes for. I should match, or exceed the performance of a crate motor from Ford! The majority of that is in the very custom ITB setup and ECU setup, so you could do this for far cheaper simply by using a 2018+ Mustang manifold or similar.

Here's how that $9k breaks down:

$3000CAD: 113k kms Gen1 F150 Coyote
$500CAD: Donor ITBs from a BMW M5
$2000CAD: Custom ITB setup using aforementioned ITBs
$500CAD: Boundary Racing Pumps billet oil pump
$300CAD: Used Boss 302 Cams
$2000CAD: Link G4+ Thunder+custom modified harness


I'll need some miscellaneous stuff like my custom fuel rails and BMW throttle actuators (which are fairly cheap used at around ~$200 a set), so for sure, absolutely, under 10k CAD all said and done for the motor setup.

Disregarding the custom ITB setup which can be swapped for any other Coyote intake manifold, for essentially half the price, I have a Mustang Coyote with .5 less compression. Or, a better way to look at it, for a little less than what a crate Coyote goes for, I have a standalone ECU and custom ITBs!

If you really wanted to work on a budget - you could easily score a higher mileage Gen1 for under $1500USD, and completely disregard the internals, only changing the intake. That would get you a Coyote powerplant for quite a budget!

Also as a final note: The gen1 engines don't have the plasma'd cylinder sleeves. I'm scared of touching that kinda tech (hopefully I never have to), so I'm happy I have a regularly sleeved engine. Haha.


Are you gonna slam it?

Yes, I'm sorry ��



If you've made it this far, thank you! I'm looking forward to feedback and criticism from this community - and I'll accept all of it in earnest!