An exercise in overthinking - Junits15's street build

[junits15]

Hey all,

I've had my 2019 Mustang GT for a little over 6 months and 12k miles and I've decided to start a build thread. The factory bumper-to-bumper warranty has just gone up, and I've got the itch to mod again.

The car is pictured below and is a 2019 Mustang GT PP1 manual. Was purchased with 2500 miles on the clock in 2022 from a dealer in CT. This car was someone's garage queen, never driven and definitely babied. The transmission wasn't even fully broken in when I got it.

Previously I had built a Focus ST, you can read through that whole debacle here: The Engineer's ST That build was the first time I ever modded anything, or did any work on a car outside of regularly scheduled and required maintenance and repairs. In that thread you can basically watch me learn how to mod a car in real time lmao. That car was traded for this mustang when the trade in value was at it's peak, before I un-modded the car it was making ~370WHP and ~350WTQ on a 30% ethanol blend. For those that don't know that car makes about 220 WHP 260 WTQ stock. The thing was a rocket ship but was completely let down by its drive layout.

This car is my daily (even in the winter yes), so huge power numbers (blowers and nitrous) are not on the menu until I get a beater. Goals for the car are as follows:

• A mild power increase (450 WHP N/A)
• handling upgrades
• cosmetic upgrades

Unlike the ST, the GT is a much better starting point, many of the issues that drove me crazy on the stock ST are not present on the mustang. Working with a RWD platform, the ceiling is much higher, and the modding community is in general more familiar with how to make this car eperfect.

My philosophy with modding is not to go as hog wild as possible but instead to take a logical approach to part upgrades. I am an engineer by education and profession, and in my line of work we don't make decisions without evidence to back them up. As it stands, the evidence right now indicates that this car has two major flaws, which I will tackle first.

1. The car's power output is octane limited from the factory
   1. An octane increase should be enough to allow the car to make good power, and can be achieved in many different ways. I have a plan in action for this item, but it's not quite ready to share. Overcoming the octane limitation of the stock car on pump gas represents an interesting challenge that I'm excited to tackle! The method I'm planning is certainly unique for an N/A American V8 and I believe will yield great results
2. The car's chassis and overall dynamic performance leaves something to be desired.
   1. Chassis improvements are a bit more straightforward, I'm considering a kit from steeda or similar, but right now I'm still feeling out the car and learning what it's limits are. More to come on this front.
   2. I believe a re-gear is in order, 4.56 or 4.88 depending on how I feel and what I am able to see others achieve. I've been reading up on this and it seems there is some limitation in the BCM on this. Either way I know it can be done and its in the cards. The major issue with this is that gearing up the rear end will completely decimate this car's abilities in the snow. So this will absolutely have to wait until I have a winter beater for messy days.

I'm going to be self tuning this car, unless I hit a major roadblock. I'm using an MPVI3, and so far its been super fun to learn how this works. While it would be easy to just go to a tuner and get a custom tune made, it's less money for me in the long run to do all of the adjustments myself. Frankly I have confidence that I'll do just as good of a job. Since the car is N/A and will be for a while, all I'm doing is WOT tuning. The control system in the Gen3 Coyote ECM is not for the faint of heart, but I'm slowly breaking it down and making progress. I have a working octane booster tune, and I think that's great progress.

Additionally, I'll be keeping a close record of every dollar I spend on this car, because apparently I like to feel bad about myself I'll also be keeping detailed buy-sheets, so if you or anyone you know wants to replicate anything I've done you'll have a detailed list of every part I used and where I got it from.

Buysheets
Google Drive - WMI buysheet

Thanks for checking in! More updates will follow!

Sponsored

 

[junits15]

As many of us know, there are a lot of opinions on this any many other forums regarding the most appropriate way to extract extra power from this motor. In stock form a Gen3 coyote with quality Premium fuel can put down just a touch under 400WHP. Opinions regarding intake manifolds, headers, exhausts, intake tubes, throttle bodies, air filters and countless other mods at times contradict each other and become confusing.

In general with natural aspiration the only angles we can play are:

• Reduce airflow restrictions
• increase ignition timing

Airflow restrictions (or lack thereof):
We've heard time and time again that a motor is an air pump, what is typically left out of that definition is that a motor is a pulsed air pump. Air enters the motor in pulses, and exhaust exists the motor in pulses. This is a critical parameter to understand in a naturally aspirated application.

What does this mean? This means that things like the diameter of the intake runners, the length of the intake runners, the diameter of the exhaust headers, and the length of the exhaust headers all play a role in when the motor makes its power. These things effect the resonant points of the system, which is to say these items effect when the system will operate with the least losses and in turn create the most crank torque. This is where a lot of confusion begins to appear. The stock headers and intake manifold do not restrict airflow to the motor. See the plot below:

The light blue graph shows the data coming off the mass airflow sensor. This pull was done on a particularly cold day with nice dense air, as a result we are seeing just shy of 50 lb/min of airflow. This airflow mass is enough to theoretically support horsepower in the high 400's, if we used our general rule of thumb we would (wrongly) assume that this car is making 490hp with proper fuel. We know in practice that this is not true. A more realistic airflow mass (on a warmer day) is more like 47 lbs/min.

The takeaway is that we're flowing enough air through the motor on stock hardware to make significantly more power than the stock motor makes. The setup used during this pull is a fully stock Gen3 coyote with a K&N panel filter.

The stock intake manifold and exhaust headers are tuned in such a way that they provide good performance over the entire rev-range. When we do things like switch to longtubes, or ported manifolds, we are not removing a restriction, rather we are changing the resonant point of the system to be at a higher RPM. This allows us to make more power at the top of the rev-range, but is often at the expense of low RPM fuel consumption or power. The IMRC in the OEM manifold gives the stock setup two resonant points, one at low RPM and one at high RPM. A feature that's been in German cars since the early 2000's and attempts to get the best of both worlds.

With all of this said, I will not be doing any airflow mods, I find those parts to be exceedingly expensive for the gains they provide. I want this car to remain emissions compliant as well, which puts all header upgrades out of the questions. Given the ability of the stock car to flow 500HP worth of air, I do not believe that switching these items is worth it for me. This is why my first order of business will be to tackle the octane limitation of the stock engine.

Increase ignition timing:
A little background, for gasoline engines, when we increase ignition timing we make more power. As we increase ignition timing at some point we will either knock or actually start to make less power.

The maximum timing we can run before we make less power is called MBT (maximum brake torque) timing. This value is baked into the stock tune. There is question on weather or not the Ford factory values for MBT are real or if they are artificially low. For my purposes I will assume they are real, I would need several hours on a dyno to prove otherwise.

Ford uses borderline timing as well, this is a starting point several degrees below MBT that the car runs. The knock feedback loop adds to this value (up to MBT) or subtracts from this value as needed to protect the motor.

The graph below shows a pull on 93 octane, we see the programmed in MBT timing curve (blue), the actual timing curve (pink), and the stock borderline timing curve (gold).

The name of the game is to get that pink curve slammed up against the blue curve at all times, like this:

That's 24* of timing at redline, an additional 4* over stock 93 octane. This pull was done with VP Octanium in the tank. The stuff works great, but I dislike the way it works and the buildup it leaves in the engine. Additionally, the gold curve is fairly far away form the blue curve, so we're relying on a lot of knock advance to get us to MBT. Which is why there is a considerable amount of time where the pink curve is not at MBT.

^ not at MBT, this is torque left on the table. This is easily fixed with some adjustments to the borderline tables, but I thought I'd point it out.


So with some octane, and a little tuning we can max out the stock motor timing, the question is how to reliably do this. Most people do ethanol, I don't have any ethanol nearby, so I'm going to do water/methanol injection.

Don't do WMI on stock cats lol

 

[junits15]

WMI hardware:

im not using a kit I’m pricing this setup together myself. Here is what I have so far:

devils own 2.25gal meth tank with -6AN bulkhead

BV2000TRN075A turbine flow meter from Omega ($100 for this sensor alone )

eBay special throttle body spacer with 2 ports

 

[junits15]

here is a snapshot of the whole buysheet with costs, suppliers part numbers and quantities:

This is not at all a cheap build its very much a money-no-object setup.

It will be based around the Syvecs WMI controller:
https://www.syvecs.com/product/syvecs-wmi/
This unit is by far the most well featured and configurable WMI controller on the market and can be used for any car with OBD2. Not cheap, but perfect.

A general overview of the system plan is as follows:
- 10GPH of nozzles (2x 5GPH nozzles)
- a flow sensor (pump lowside)
- a pressure sensor (pump highside)
- solenoid valve (needed since I'll be injecting into vacuum)
- 2.25 Gallon race tank
- standard AEM WMI pump
- Syvecs WMI controller (CAN data triggered)
- entirely plumbed with -6 and -4AN teflon lines.


Everything else is just support, this weekend I'll be running some high current lines from the battery junction box to the rear of the car and installing an aux fuse box. One 10AWG wire for the WMI and a 6AWG for an eventual sub amp.

I learned from my last car that the thing that makes WMI hard to install is mostly the wiring, there are a lot of signals to keep track of and they all need to be routed nicely for reliability's sake.

 

[junits15]

Initital wiring is 95% complete, I need to extend the main wires in the engine a bit more.

First, jack up ya cah

Found this connector under the passenger side wheel liner, for magneride I assume?

Wires go through this hole

and then down through an unused port on the main grommet. I also threaded 4 18 AWG wires, which can be used for sensors, triggers, and the solenoid. I only really needed one for the solenoid but it never hurts to have extra, and If I need to do this again I'll probably jump off a bridge. I hate running wires through the firewall.

I bundled up the smaller wires for now. The plan is to mount the solenoid behind the wheel liner, somewhere in this area. I may use the extra two for a pressure sensor, or they might become trigger wires. I haven't decided yet.

The 4 small wires, 6AWG, and 10 AWG wire travel along the body at the bottom of the door frame with the main harness and then pop out next to the factory subwoofer in the trunk. I wrapped the loom in tessa tape to protect it and give it a factory look.

the Thick 6 AWG wire is left unconnected for now it will eventually go to a sub amp, I wanted to run it because I didn't want to spend all this effort and time putting wiring primary wires only to have to do it again.

the 10 AWG wire was terminated and attached to this auxiliary fuse box. This supports 6 30A circuits (Though I wouldn't recommend going near that limit) and has LED's to indicate a blown fuse. I used 3M VHB to stick it to the back wall of the spare tire well. The ground goes to a factory ground lug in the trunk. Its just an amazon special and its meant for a boat, but it looks pretty slick and it should make my life much simpler.

The last thing I need to do is connect the wires to the main fuze box at the front, unfortunately I made my life complicated and accidentally cut the wires too short. So that will be an update that will come later.

 

[COVID19]

Beautiful car!
Good luck with your build.

 

[junits15]

Procuring the special connector for the Syvecs WMI controller:

The Syvecs WMI controller uses an off the shelf connector from TE connectivity, and while their choice is perfect from an engineering and reliability standpoint, it is awful for a regular person to get ahold of. There are not many places that you can buy this connector and these pins from, and of the ones that do have this part in stock, about half have a really high minimum order quantity.

A quick check revealed that the connector housing, and 2 of 3 types of available pins are 0 stock from digikey and have a 4 month lead time These parts were both in stock last week. This got me spooked so I'm ordering them now before all the distributors sell out even though the project is still months out.

The pins are available in a -5, a -4 and a -3 variant, for 22AWG, 20AWG and 18AWG respectively, my preference was for the -3, but its only available in full reels of 7000...

I was able to snag a housing direct from the manufacturer, but unfortunately I was forced to buy the 22AWG pin variant. I think this will be fine, most pins on the housing are redundant so I don't expect voltage drop the be a big issue.

Also TE required me to indicate the final use case and if it will be exported. I gotta say I'm not used to having to sign what is essentially an itar agreement for a plastic connector, but here we are.

These connectors require a crimping tool, this wont work with just pliers or a normal crimper, I have an old one I bought off eBay some years ago, if anyone is looking to duplicate this you'll need a tool like this. A real crimper will be >$500 so I just deal with the ebay one and visually inspect and test each crimp, if you're careful you'll have no issues. You can also add solder to the joints after they are crimped but you need to be careful. Too much solder will foul the connector and not allow it to mate.

And one last thing, if you're ever looking to buy electrical components, industrial widgets, or other related items I always recommend www.octopart.com you enter in the manufacturer part number of the item you want to buy and it lists all the distributors that have it in stock at the point in time, as well as cost, and cost breakdown. really useful!

 

[junits15]

more parts ordered:

Prices are great at beefcake, much less than summit. I want to get the line run and the solenoid mounted. Then all of what I consider the annoying parts of this install will be done. Which is to say I'll be done crawling around under and in the car.

 

[junits15]

Updates updates updates

power is fully wired in. Main fuse box is mounted in the small area next to the battery box. I used the Christmas tree there to locate the fuse holder and some 3M VHB to lock it in place. It’s very sturdy.

I used about a foot of 4AWG wire to jump from the battery to the fuse box. I attached it to the positive thermal in the same way as shown here:
https://www.mustang6g.com/forums/th...at-install-long-post-heavy-pic-warning.78694/


I disassembled the positive terminal and threaded the clamping parts through the terminal lug. When you crank down the bolt it pulls the lug tight onto the terminal. Nice install method and works very well. I wish they had used the same method as they did on the negative terminal and given us an easy place to attach to.

I’ll be adding an AGU fuse holder inside the battery box to protect the entire thing. With the cover on the battery box this install is invisible.

 

[junits15]

I also ordered the main event…

stupid money for this thing but I guess it is what it is, I’m adamant that this is the best on the market. Hell I think this could even be repurposed to control nitrous if you wanted.

 

[junits15]

Harness made for testing and firmware development. A perk of my job is that I have full use of this professional rework station. Made very light work of this task.

The paperwork all calls for this 34 way connector but the pictures show the 26 way version. I hope it was just changed at some point and it’s not an error, I guess I’ll find out when it shows up.

CAN bus wires must be twisted or else it won’t work. Also you cannot make this harness without a crimp tool. Look how small these pins are.

 

[junits15]

good news!

I ordered the entire buysheet! Ended up buying a mix from summit and amazon. I did hold off on the final 2 -4AN hoses that go from the solenoid to the nozzles, just because I can't really predict how long they need to be. I opted to buy pre-made crimped AN lines instead of making my own, just for peace of mind that they wont leak. Also because I don't like making AN lines lol.

The total spent on this project is just shy of $2k. That includes all shipping, taxes, consumables, and every single last item needed to do this. This weekend I'll be running the meth line up to the passenger side front wheel well. Pictures will follow!

 

[Duece McCracken]

good news!

I ordered the entire buysheet! Ended up buying a mix from summit and amazon. I did hold off on the final 2 -4AN hoses that go from the solenoid to the nozzles, just because I can't really predict how long they need to be. I opted to buy pre-made crimped AN lines instead of making my own, just for peace of mind that they wont leak. Also because I don't like making AN lines lol.

The total spent on this project is just shy of $2k. This weekend I'll be running the meth line up to the passenger side front wheel well. Pictures will follow!

Twisted pairs, lol

2k? Wowee!

Glad I have ethanol around!

 

[junits15]

Twisted pairs, lol

2k? Wowee!

Glad I have ethanol around!

Dude I'd give anything to have ethanol nearby, but its just not here.

It's basically nonexistent near me, there are 4 stations in my entire state, and the closest one is 40 minutes each way. Don't have a garage, so can't store a huge drum, and even if I did it would still be awful.

I get 17 MPG now, ethanol will be at least 30% worse call it 10MPG for error. That's 20 gallons per week, which means a 55 gallon drum of ethanol will literally only last me about 2.5 weeks of driving to work. It would take me nearly 5 weeks to burn that much 93. Its absolutely mental, and I can't do it. The only way I could run e85 24/7 in the mustang is if I literally had like 150 gallons on hand at any given time, on an automatic refill from a distributor.

Also the shit is well over $4/gallon near me because its trucked halfway across the country to get here.

LT's and a manifold aren't what I want on a street car, too loud, inspection issues, bleh. Octane booster says right on the can that its not recommended for long term use in a catted vehicle except for very low doses. Nitrous does work but good luck finding someone to fill it.

That's how I landed on meth, the reason the install is 2k is because I'm using the Syvecs Standalone WMI controller and all braided stainless AN line. If I wanted to be cheap I could have done this for under $1k, but I want the system to last and be reliable so I didn't cut corners. Syvec's really went the extra mile with their controller.

 

[junits15]

here's the buy-sheet:

Sponsored