Vorshlag 2015 Mustang GT Road Race Build #TRIGGER

Vorshlag-Fair

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That is A LOT of spam...
Really? Did you read that post?

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Most of the things I pictured, weighed, and showed in that series of posts are things we don't even sell. Clutches, water pumps, door lightening tricks, radiator mounting, upper tire bar, drivetrain weights, intake manifolds, front end conversions...

What do I get financially from talking about these issues - I mean to be "SPAM" would imply that of the 60K characters I wrote in that last update they would all generate some sort of sales for us. PLEASE TELL ME, so I can "cash in" on my tech tips.

tech-tip-L.jpg


Literally 90% of that massive post - which I spent 25+ hours photographing, writing, and editing - had to do with step by step tips that show how to help save time, money, and hassles. For products we do not and will not ever sell. This section above about saving money on commonly damaged headlights. Or the RockAuto trick for saving money on the radiator support piece - which is very often broken on wrecked S550s.

What do I get from this "SPAM"? I'd love to know. My wife, who hounds me for working late writing up these build thread updates after the employees have gone or on the weekends, would love to see that "forum build thread" money. ;)

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In the very first part of that post I openly showed this screenshot which linked to the LS550 swap items we are hoping to sell from this build. From that entire post, those 7 pieces are what we are trying to sell, and I don't hide that fact. I am running a business and have to sell things to keep the doors open, to keep my employees paid, to have a reason to do all of this.

Hopefully my "tech vs spam" ratio is better than other people here. Please, point to any active sponsoring vendor here that is sharing more pictures, tech tips, and buying tips. That has build detailed threads and a history of sharing this type of thing going back 30+ years, all the way back to "pre-forum" days of email lists, where I did the same thing.

Just give me one example, because I'd love to meet them and share stories of haters and hacks who nit pick anything they write, too. :)

Cheers,
 

AHaze

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Honest question: Is there a good reason for someone starting from scratch to build an LS powered S550 track car rather than starting with a 5th gen Camaro SS? I mean strictly from the perspective of wanting to be competitive, not just because 5th gen Camaros are kinda goofy looking.
I have to think starting with an LS powered car would reduce the complexity and cost of the project significantly and I can't see where the S550 chassis offers any major advantages over the Chevy.
I've never turned a lap on a road course so I'm not trying to flex my racing knowledge here. I'm genuinely interested in your thoughts on this.
 

tjm73

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Honest question: Is there a good reason for someone starting from scratch to build an LS powered S550 track car rather than starting with a 5th gen Camaro SS? I mean strictly from the perspective of wanting to be competitive, not just because 5th gen Camaros are kinda goofy looking.
I have to think starting with an LS powered car would reduce the complexity and cost of the project significantly and I can't see where the S550 chassis offers any major advantages over the Chevy.
I've never turned a lap on a road course so I'm not trying to flex my racing knowledge here. I'm genuinely interested in your thoughts on this.

Interesting question. I'm replying so I can remember to see the answer.
 

frank s

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Honest question: Is there a good reason for someone starting from scratch to build an LS powered S550 track car rather than starting with a 5th gen Camaro SS? I mean strictly from the perspective of wanting to be competitive, not just because 5th gen Camaros are kinda goofy looking.
I have to think starting with an LS powered car would reduce the complexity and cost of the project significantly and I can't see where the S550 chassis offers any major advantages over the Chevy.
I've never turned a lap on a road course so I'm not trying to flex my racing knowledge here. I'm genuinely interested in your thoughts on this.

I believe that at a certain level of building a racing car of any sort, the original chassis is of as little importance as what color the car will be. It gets stripped down to below bare bones and reassembled with whatever components are most familiar and accessible to the builder. Just a matter of preference by then, and to begin with, actually.
 

modernbeat

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Honest question: Is there a good reason for someone starting from scratch to build an LS powered S550 track car rather than starting with a 5th gen Camaro SS? I mean strictly from the perspective of wanting to be competitive, not just because 5th gen Camaros are kinda goofy looking...

Well, that's a yes and no.

The Mustang has a number of things going for it, and the Camaro has some things going for it.
My #1 beef with the Camaro (5th or 6th gen) is the poor ABS, and the #1 benefit of the Mustang is it's excellent ABS programming for track use.
Beyond that, I like the Mustang suspension more than the Camaro. I really like the Mustang Super 8.8 differential. And I like that the Mustang is still stamped steel and doesn't have cast strut towers. I also like the EPAS (electronic power steering) that comes in these Mustangs. What I don't like is the MT82 transmission (it got better for 2018, but it's still no Tremec) and the limits the Coyote engine has for track use.

For a not-quite-full-effort build, starting with the Mustang makes sense.

For a low-effort build, you can deal with the Camaro ABS (it's at least better than C6 Corvette ABS), the engine has great potential, and you get a decent Tremec, though it isn't a direct shift like the aftermarket Tremecs.

For a true full-effort build, that would be a tubeframe car, or a tubeframe with a floorpan and partial firewall grafted in for rules reasons. But the labor to build that car is just too much, and the additional gains beyond what we should get with this Mustang are just too small for us to pursue.

Terry and I talked a lot about it and decided that for what we wanted, which was a very high powered car building on our previous development, the swap makes sense. This first iteration will have a mid powered engine that makes similar power to the original Coyote, but has some weight taken out. So the first round of results should show off what happens when you lighten the car. The next round of results will show off the rest of our development.
 

Sky Render

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I think one of the points of this build is if you have an S-550 that's already prepped, blow up a motor, and can't afford a built Coyote, you could maybe put a cheap LS in instead.
 

Pentalab

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Jason, are you saying the LS engine is lighter than the coyote ? Where is this weight reduction coming from ?
 

Vorshlag-Fair

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Project Update for September 3rd, 2021: Yikes, 13 months passed without an update on this build thread! There were a million reasons why we haven't updated this thread, and why we had an 8 month hiatus from work on it. Mostly we got SUPER busy with parts sales during the pandemic, and then 6 customer owned car builds that had priority over my personal car. We completed a decent chunk of work after my July 2020 post before this car got "put on ice" for 8 months, which we will cover now.



In the Spring of 2021 we had a 800 sf metal barn built (below right), and this S550 Mustang, my all carbon C6 Z06 chassis, my tractor, and my 1/2 ton truck all got moved into there - which opened up a lot more working room in the main shop (below left). Since then several customer cars in the shop have gotten to finish points (and one went to "paint jail"), so the LS550 Mustang is back in here again and work has resumed (August 2021).



We are once gain working to finish the "Phase 1" aspect of this Mustang LS swapped build. Let's start out this update with July to December 2020 work, then we can jump ahead to August 2021 tasks.

PLASTIC DISTRACTION + FIRST HOLLEY EFI COMPLETION

In this 8 month hiatus of LS550 work we did buy this 2006 Corvette (below) for my wife Amy in May 2021, and worked on that a bit. That car was purchased to use for C6 product development and testing, plus as an excuse to get to the track more often in a "pretty good car" in stock form. I have performed 4 track tests in this plastic turd to try to get a good "baseline lap" to build upon, but it has not gone smoothly. Long story, which you can read about in that C6 development thread (Project New Balance).



Also during the past couple of months we got our 1st Holley EFI converted LS customer car started up and it works great. This Cadillac CTS-V endurance race car (build thread here) has a virtual clone of the engine in my LS550 - its also a stroker 383" LS1 cathedral port engine built by HorsePower Research, also has a Fast 102 intake, similar cam, and a Holley Terminator X-Max (vs the Holley Dominator EFI on my Mustang). It sounds rowdy and we should have dyno numbers on that car soon. Seeing that car get to this final stage really fired me up to finish mine!



After working with it first hand now I can say that the Holley software is very pretty to work with, and we learned a lot on this first Holley EFI install. We have 3 other Holley EFI equipped builds in process (our E46 LS swapped endurance race car, a customer's 1967 LS7 swapped Mustang track car, and my 2015 LS swapped Mustang), so seeing this first one fire up was a huge boost.



This CTS-V also got a PowerTune 7" LCD digital dash, which is their first one with a Holley CAN interface (and we might use this dash on our LS550 build). Also of note is the stand-alone Mk60 ABS we swapped onto this car (not our first), which replaced a "Cadillac Racing" ABS unit that didn't work (funny enough - it was a factory C6 Corvette unit!)

PRODUCTION DRIVESHAFT INSTALLED

We've seen a couple of "one off" LS swaps on the S550 but not any comprehensive "kit" that has engine mounts, trans crossmember, long tube headers, driveshaft, and transmission solutions. We made a decision early on to attack the Road Race customer first, and they don't want a Powerglide or other automatic, they want a manual transmission. The T56 Magnum XL is THE best option for road course use under $20K, and the bellhousing-to-shifter length is perfect for the S197 and S550 chassis Mustangs, so that is what we built our "Stage 0" kit around.



This makes for a much shorter driveshaft than the long 2-piece OEM unit that came on any S550 - because the direct shift T56 Magnum transmission is much longer than the remote shifted Getrag MT-82 6 speed in the 5.0L Mustangs or the Tremec TR-3160 6 speed from the Shelby GT350. Since this Tremec T56 is so different from any OEM transmission in this chassis, there is no way of adapting the stock prop shaft - we needed an all new design.



The T56 front slip yoke is unique to that transmission and has a standard U-joint. Out back also uses a U-joint, but as we have learned the hard way (see our 2018 Mustang build thread) there are TWO different sized rear differential flanges in the S550. Our driveshaft supplier makes a universal rear flange that works on both diameters, using a second set of holes and a spacer shim that goes inside the flange.



Once all of the OEM bolts and binary washers arrived we were ready to install our production driveshaft in late July 2020. The stock binary washers (which we sourced from Ford) needed to be shaved down a hair when we used the radial shim to adapt for the smaller S550 flange inside the rear axle flange cup. You won't need to do this slight modification if you have a rear axle flange cup that has the smaller diameter - as you won't need the adapter ring.



Other than that slight tweak (we will have these modified binary washers laser cut and offer those + the OEM bolts for our driveshaft kit) the driveshaft install was a breeze, and the large diameter unit looks plenty beefy. Shouldn't be an issue with our 550 hp engine, but the more powerful "Phase 2 engine" might get a carbon shaft. We will run the numbers and see.

4 PORT STEAM VENT KIT

Most LS engines that come in cars have a 2-port steam vent, like the LS7 crate engine shown below at left. This merges one steam port on each cylinder head across the front, then this tube is plumbed to the coolant reservoir. We would rather use a 4 port steam vent system on LS engines, for more even cooling & steam venting.



The 4 port is used on the trucks and on our E46 LS endurance car we modified a truck unit to fit with the LS2 Dorman intake, or that we re-used on my truck's built 5.7L LS (above right). When we want a 4-port and the steel OEM truck LS unit won't fit, we look at the aftermarket. Normally we will spend around $200 to buy the TFS branded 2- or 4-port steam vent kit for an LS. These come with billet fittings that bolt to the heads at both ends, plus the braided lines to attach them to a single port. This is then tied into the top of the radiator or into the remote coolant reservoir.



We bought the TFS 4-port kit for use with this FAST LSXR 102 intake, but the FAST intake is pretty bulky and the TFS steam port adapters were hitting the body of the manifold. Instead of grinding on the $1000 intake manifold, we went with the only 4-port kit that was known to fit the FAST LSXR 102 - a unit from Nitrous Outlet. It is 4 billet adapters for the ports with one that has a "tree". The tree has inlets from 3 other ports and one outlet to go to the radiator or reservoir.



This kit is built specifically for this FAST LSXR 102 on a cathedral headed LS engine manifold and installation went pretty smoothly. The head gaskets utilized by HPR were setup for 2 port front vents only, but the rear ports in the heads are there - you just have to drill out a rivet that covers that hole up - which we did. Evan used his 90 deg / right angle drill to take the head off the rivets, with the intake ports on the heads taped up to avoid any debris (if we had told this to HPR they would have pre-drilled the head gaskets before they were installed). Once the rivet head was drilled off, Evan used a pick to dig out the lower portion of the rivet, opening up the head gaskets' rear ports. On the CTS-V (above right) we used the exact same kit and tied the line into the remote reservoir - which we will do on the LS550 as well.


continued below
 

Vorshlag-Fair

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CUSTOM RADIATOR, ROLL MOUNT, & MODS


We have plans for much more power than this 385" stroker will make, as well as significant aero mods down the road. To "future proof" this build, and give us more cooling than we need with the Phase 1 engine, I wanted a much larger radiator than the stock S550 mounting position would allow for.



Rolling the radiator is something we do on virtually every road course build that goes through our shop. This forward tilt allows for a larger radiator core frontal area to fit within the same space, so the radiator is larger than the grill opening. It can also allow for room ABOVE the radiator to cleanly route a cold air tube, to feed the radiator from the lower grill only, or for hood venting.



Rolling the radiator forward a radical amount (normally involving a custom tube front bumper pushed forward to the bumper cover skin, like we have done on the LS550) also opens up a LOT of room in front of the engine. The two cars above (86 LS swap above left, E46 LS swap above right) have gained this room, which makes working on them easier



A steep radiator roll also lines up the "exhaust" from the radiator to more easily point upwards to some waiting hood vents. If you get really creative (69 Camaro tube frame car, above) you can duct the heat exchangers to a sweeping set of hood vents, and this makes for a lot of good airflow, which aids both downforce and cooling with a splitter. That's what they call a win-win.



Now we're not getting as crazy on the LS550 as we did on the 69 Camaro - which again, was a tube frame build with the engine (and driver) shoved back two feet - but we're rolling this radiator more than we typically do. Yes, we pushed the bumper beam way forward to gain some additional fore-aft room for this heat exchanger.



We ordered this custom built Howe (circle track) radiator in March of 2020 and started mocking it up in the Mustang as we installed the plastic and steel upper radiator support - which is now really just a front bumper cover bracket. The roll we were able to get was 34 degrees down from vertical and the top of this massive 28.75" x 20" x 3" radiator almost touches the front factory grill plastics.



I ordered this one as a dual pass design, with the radiator inlet and outlet on the same (right) side, which lines up nicely with our engine's LS7 water pump - which I talked about in a previous forum update.



With the massive radiator in place you can stand in front of the LS engine and work on it, and have plenty of room to move around. This is because we maximized engine setback (without cutting the firewall) and moved the radiator out of the way. Think of the radiator duct box we could squeeze in there! Well.... maybe down the road in Phase 2.



To make modified "pin" mounts Brad machined some aluminum bar on the lathe, made lower corner brackets, and Myles TIG welded the tubes onto those and then welded those onto the bottom end tanks. The radiator cap "neck" was cut off, to later be patched with a welded plate (the cap will be in the high mounted remote coolant reservoir).



With the pins in place at the matching 34 degree angle the lower radiator was mounted into the stock bushings set into the lower subframe.



The upper radiator mount is a simple, temporary bracket that was slipped in on top and bolted to the factory hood latch holes (we have added Aerocatch latch pins and latches already). I will show more of the radiator ducting and hoses in the next update.

BRAKE LINES

This salvage car was pretty stripped when I bought it in Georgia so we had to hit the salvage yards to buy an ABS hydraulic unit, but for a new master cylinder and booster from Motorcraft (which I showed previously).



For the main engine bay hard brake lines it is fairly inexpensive to buy brand new ones from Ford. We got Motorcraft rear flex lines as well, until we make some braided lines for the back of an S550 (the front lines are braided lines we had built for the Powerbrake 6 piston kit).



Double checking the metric thread pitch on the master and lines, all good. The mangled stock lines were removed and the all new engine bay hard lines went in, no sweat.



The rear flex lines are well made and have multiple brackets to hold them out of the way of the wheel and tire. Again, these worked great on our 2018 GT for 2 seasons of track abuse, and we will look towards making a stainless braided version of these in the future. But for now - we have a complete brake hydraulic system!

EFI SENSORS, INJECTORS, TB, & INTAKE INSTALLED

When installing an aftermarket Electronic Fuel Injection (EFI) system you will want to follow their directions when it comes to sensor use. Holley likes to use higher end 0-100 psi sensors for pressure (fuel and oil), and they want to sell them to you at a pretty high price. Luckily the DIY crowd has tested a much more cost effective version that is $20 vs $149, and we bought these for our LS550 build (and have verified they work properly on another Holley EFI install with secondary gauges). The other one will go on the fuel pressure regulator, which has a spare 1/8" NPT port.



These pressure sensors are all 1/8" NPT male, so we had to get an adapter for the back of the block, where an OEM oil pressure sensor for an LS resides. What you need as a 16mm Male to 1/8-27 NPT Female Thread Adapter, with an O-Ring (ORB). We got a brass adapter on this car but found a proper Fragola aluminum adapter on the Cadillac build.



With that sensor & adapter in place, and the 4-port NOS Outlet steam vent kit installed, we could finally install the FAST intake, FAST fuel rail, and injectors.



We went with a set of Fuel Injector Clinic 50lb/hr (@ 3 Bar) / 525cc/min Injectors, with an EV6 Connector, LS2 Height (53mm), part number IS302-0525H - which I bought from my tuner Jon Simpson. My advice is TRUST your tuner on injectors and just use what he likes, so that the flow characteristics are correct for his tuning methods. For the throttle body, since we were limited to a 102 mm opening on the intake we went with eBay's finest 102 DBW throttle body. They make all of the high end electronic TBs in China, too, except they charge like $1000-1500. We'll see how that gamble worked (it has worked on the Caddy).

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Vorshlag-Fair

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Before the intake went on "for good" Brad found this vacuum hose with a built in 90 deg bend, with the Dorman part number shown in the image above. The second picture above shows how much room we have with the standard deck height LS engine installed into the S550 with our mounts, up to the flat Anderson Composites carbon hood. For reasons we might utilize later.



When all of that was buttoned up, the FAST intake had the injectors and fuel rails installed, then the throttle body, then it went onto the engine for the last time - no more mockup! We will make the fuel rail crossover hose when we plumb the fuel system.

MORE SALVAGE YARD HELP!

Many things on this salvaged S550 chassis were missing, and when we bought the used fuel tank all of the internal bits were long gone. So I reached out to my buddy Paul @ Tri-State Auto Parts, just outside of Memphis. He has helped us track down a lot of long lost items for this build and others!



Paul likes my memes so he sent the box marked as such! He helped us source some fuel pump parts/sump, used ABS units, various wiring pigtails, and more.



Having nothing of the stock harness makes for a lot of extra work, but I was in a rush when I picked the car up in a made 38 hour straight road trip, and missed this very obvious issue (missing harness). Again, starting with an utterly stripped car likely cost us 6 months of time and many thousands of dollars in extra parts / chasing. Live and learn.

IGNITION COIL BRANDS (DON'T MATTER!)

One thing I did not have laying around was a set of ignition coils, and an LS engine needs eight of them. GM coils come in 3 basic shapes and types, but they all function virtually the same way. You just have to make sure the coil harness has the right style plugs to drive the coils.



Since all LS engines have one coil per cylinder, these are not heavily taxed - even up to around 1500 hp. One thing I've learned in 2 decades of LS swaps - the ignition coil brand and cost does not matter. Not one bit. They want you to buy the $80-125/each units, and will flash them up with different colors or features, but the simple fact is, it is just a dumb transformer. It converts 12 volts to tens of thousands of volts, to drive the spark. That's it.



To prove that coils don't matter on an engine with 8 of them I bought 8 of the cheapest coils I could find on Rock Auto for a C6 Corvette LS7. If there is a tuning issue of course we will change them out, to rule them out. But I suspect they will work fine (hint: I've used cheap coils in the past and NEVER had a failure!)

IN PROCESS WEIGHT CHECK - 9/29/20

We do these periodic weight checks during all of our builds, just to see where we are and to hopefully get an idea of where the project will end up on weight, with a little extrapolation. We did this one in late September 2020....



This weight worries me a bit, as I have bet a steak dinner with a buddy that this will be "under 3000 pounds" in our first track outing, sans driver. With a weight of 2920 lbs here - and no fluids, exhaust, or oil coolers - I might come up short. If I have to cheat I will toss the carbon doors on, which are another 80 pounds lighter than these gutted steel doors. I want that free steak dinner, and I REALLY want this pig to be 600 pounds lighter than my 2018 GT!

HOLLEY EFI & CHASSIS WIRING WORK

When we stopped working on this project in December 2020, we were buried with customer car work. I had forgotten how far we had gotten on the wiring and EFI upgrade on this build until I started researching the photo gallery for this build to write this update. We're pretty close!



We are using the Holley Dominator for this build, unlike the 3 Holley Terminator X-Max swaps we are doing elsewhere in the shop. The Dominator is very similar to the Terminator, except it has a lot more inputs, outputs, and potentially a better traction control functionality. We might not use all of this I/O on the Phase 1 build, but we are trying to future proof this work for additional power (and needs) down the road.



The Dominator doesn't come with a complete engine harness like the Terminator does, and it costs about 3x as much. So Brad had to piece together wiring harness modules and sub-harnesses. A bit more work, and we bought a 2015 Mustang wiring diagram book from Ford to help with some of the limited integration we will be doing with chassis-side items (some light circuits, some switches, etc).


We sourced a 21 circuit "hot rod" wiring harness from Painless Wiring (10102) - which is made across town, right here in the USA. We have used this harness on a dozen cars and it is more than enough for a race car, with plenty of circuits. "But why not a PDM!" Well why not a $25K re-wire of a car? Because the time clocks don't care how much you spent on wiring. This doesn't make your car faster, and we haven't seen failures, so why waste the time/money?



We weighed this harness at 7.6 pounds, which matches the manufacturer's 7.54 pound claim. Again, we have used this exact same harness and part number on numerous cars with success, and it didn't cost twenty grand. If we were building an F1 car of course we would do something much more elaborate, but for a ratty salvage titled and wrecked 2015 Mustang, this fits the build.



Brad started looking at the routing and layout of this chassis harness, and we tested a number of places to mount the main fuse / relay block. We narrowed it down to two places - surface mounted in a panel under the radio or hidden inside the glove box.



Ultimately I decided to mount the fuse box inside the glove box area, along with the Holley Dominator ECU. Brad made this cardboard template then built this 2 piece bracket assembly, above.



This bracket holds the Holley engine computer and the fuse box portion of the Painless Wiring chassis harness. This can always be accessed quickly when needed, but out of sight when it is working fine. If we ever do an Optima OUSCI event in this car, it would at least be worth some D&E points, ha!



I am happy with this install, and gives this build a bit of "is this OEM?" look while hiding the real bits out of sight. This is not made to be a show car, and not made to show off flashy bits, with some of these hidden things.

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Vorshlag-Fair

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continued from above



Brad worked on both the Painless chassis harness as well as building the Holley EFI harness. The ECM harness has to be built, pinned, etc. A lot more work than the Holley Terminator work we have done, that's for sure.



Brad was working on this until the first week of December, when we ran out of time and put the project on hold. But we are a lot closer than I remember, with most of the harness built, the firewall grommets added, lighting bits wired in, and even the timing pointer added to the engine. More on this soon!



FRONT TOW HOOK ADDED

I have fallen in love with our weld-on tow hooks on a couple of customer builds. We are adding 4 of these to all of our shop cars that get tube bumpers, as it makes loading and strapping down a race car a BREEZE inside an enclosed trailer. No more fishing straps under splitters or diffuser, or snaking them through wheels.



We have had to winch this car into the shop already, so before we did I asked Myles to plasma cut a tow hook - which he then TIG welded in place.



I cannot emphasize how handy these are to have for hauling, strapping down to dynos, and for straps inside a trailer! We will add 3 more to this car very soon.



PP1 UNDERTRAY INSTALL

When we got this car it had no front bumper cover and a smooshed hood... so it was a good time to update the front end to the 2018-21 GT front cover, which we've already covered.



I found the 2018 bumper cover at a local salvage yard, but it was a floppy noodle. With some wheelin and dealin I got the correct 2018 GT upper and lower grills, which really firmed up the nose. Then we bought the correct radiator support to mount it along the top. The 2018 fenders tied into the nose and we had the base 2018 GT lower lip leftover from my 2018 to firm up the bottom. But there was still some wobbliness in the bumper cover due to the lack of a lower undertray...



For a variety of reasons I did not want to do the first track test with a custom front splitter - I want this to be as close to the final spec of my red 2018 Mustang as possible. We'll have the same wheels, tires, brakes, suspension, seats, and approx the same power as the red car on the LS550 - just less weight (which will be a good data point - how much does weight effect lap times?). So instead of jumping ahead to aero, we needed a factory PP1 undertray...



This car came without any of these plastics, and so I bought the full PP1 kit above. Which we talk about in detail here (it is the basis of the "PP2 conversion kit", just without the $400 extended PP2 lip). Why not run without any of these lower plastics? Well two reasons. 1) the brake cooling deflectors we have installed won't work for crap without the ducted tunnels built into the PP1 undertray. 2) Running with no undertray at all is akin to driving with the hood off - it will absolutely WRECK the airflow under the car, through the coolers, and add tremendous drag. The PP1 bits are fairly inexpensive, and I'm sure we can sell these when we go to make a REAL splitter for this car later....



The images above are a tease - that's a custom dual-layer, bonded aluminum splitter with tunnels we built for another customer's race car (S197), but what is shown there is similar to what we will likely do in Phase 2 of this LS550 build. But like I said, we're trying not to get too far ahead on prep of where my red 2018 GT was on the LS550's first track test, so we will be going with stock aero and the basic PP1 undertray.



Technically my red 2018 GT (above) had the PP1 undertray and the PP2 "splitter" (see above), which was just a $400 lower lip extension + the PP1 bits. We have done an extensive write-up of the part numbers and costs associated with the PP1 + PP2 bits, located here. Since this will be a temporary setup on the LS550, we left the PP2 splitter extension off and just ran the PP1.



This PP1 undertray + bracket + center cover will give the LS550 the same thing as any 2018-up PP1 came without without the pricey $400 extended PP2 lip. This is needed to feed the front brake deflectors properly for the first few (??) track tests we will perform before we start to throw some aero bits at the car.



The install was a bit tricky, but we're getting better at this now that we have have done a few of these. Brad did the hardware the same way as he did this on my 2018 GT upgrade over the base model undertray it came with.

UNUSUALLY LARGE EXHAUST PLANS

So I am a bit of a nut when it comes to exhaust systems. Having built a lot of lighter, higher flow exhaust systems on a lot of cars over the past 35 years I have outgrown the LOUD AF systems. When I was in high school and college I had the Flowmaster stuff with dumps on a variety of 1st gen Mustangs to Fox Mustangs, but I can't deal with that noise anymore.



Honestly, a lot of event sites are tired of that nonsense as well, and more and more have put into place noise restrictions. Many have a 103 db limit, which we have been able to hit with some of our customized exhausts. The off-the-shelf Magnaflow install on my 2018 GT was SUPER loud (above left), but the upgraded version (above right) would regularly measure between 90-97 dB - which is a LOT quieter than needed to squeak under 103 dB tracks like NCM.



The thing that we have found that reduces NOISE while keeping the same or increasing FLOW is to go with a larger diameter tubing on the exhaust and a MASSIVE increase in the muffler case VOLUME. We have done this on a lot of cars and it usually INCREASES horsepower while DECREASING noise levels (measured with proper sound metering devices and SAE procedures).



Big mufflers are always harder to package... so the exhaust companies don't even make "kits" like this. Which is a shame, because this really WORKS. Unlike the S197 above (which has a custom 4 muffler 3" mandrel bent system) the routing on the S550 does not leave as much room out back for a large muffler case - and with the power level we are going for in Phase 2 we need the biggest mufflers money can buy.

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Vorshlag-Fair

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continued from above

PICKING TWO MASSIVE MAGNAFLOW MUFFLERS

The solution we have used many times to counter noisy exhaust notes on rowdy engines is to use a larger case muffler. The biggest muffler we have ever used on a car is this Magnaflow stainless 5 x 11 x 22" case beast, shown below.



We have installed one of these onto #TruckNorriSS, my 2000 Silverado with long tube headers and an HPR built engine. This truck used to have two smaller volume, chambered Magnaflow mufflers and it was pretty damned loud. The change in sound levels after we installed this SINGLE muffler was immense. This was a dual 3" into single 3" merge into this Magnaflow 12589 muffler. It did not lose any power, just got a LOT quieter.



Right after this truck exhaust change I new what the LS550 needed - two of these! Sure, they are eighteen whopping pounds apiece, but the peace and quiet of having a quiet Mustang would be worth it.

I laid out a scaled drawing of the mufflers onto a picture of the S550 trunk very early in this build, sent this to Magnaflow in an email, and asked them to sponsor a pair of these for our LS550 build in late 2019 - and they agreed. Later in 2020 when I checked up on the sponsored mufflers, they had to stop their sponsor program due to Covid, which was totally understandable. That's when I just bought two of the 12909 mufflers in the 3.5" inlet/outlet sizes I wanted to use (the 14900 versions shown are just polished vs raw stainless).



In a strange twist of fate the pair of sponsored mufflers eventually showed up in 2021, so Amy's LS swapped FRS and our LS swapped E46 BMW will get the extra mufflers (one each) that I had hurriedly paid for. Thanks, Magnaflow!

TRUNK CUT OUT

To make room for these two absolutely massive mufflers we cut the trunk floor out of the Mustang, which we do on a lot of race cars that will be getting a diffuser anyway (this one will get a diffuser, eventually). In December of 2020 we mapped out and marked out the "line of death" and Brad got to cutting...



We planned to take the cuts up to the edge of the main structural frame members and main lateral structure member in the back of the car, with a 1/2" flange left to attach to later. We would lose the ability to carry a full sized spare, which was a non-issue.



After some careful cutting the spare tire section was cut out, which totaled 8.9 pounds. More importantly it gave us room for these big mufflers.



"So much room for activities!"

RETURN TO THE SHOP - AUGUST 2021!

After many months of barn storage the Mustang came back into the shop. I had to wash the filth off of it first, as it was stuck under a tree for a few days back when the barn got foam insulation sprayed.



This car was NASTY but cleaned up quite well, since Brad had waxed it before it went out to storage. Washing this car was very cathartic.



Seeing it cleaned up and getting it back into the shop was a huge boost for me, mentally. I've been away from Time Trial competition for TWO YEARS now and it has made me grumpy AF. This car is what I will drive next on track in that format, so getting this going again is a way to shorten that gap in my track addiction.

FINAL HEADER COLLECTOR MODS + CERAMIC COATING

The production LS550 swap headers had been in the car for some time, but to fit the 3.5" exhaust we'd have to steer the collectors around some items, for a better aim at some open spaces in the floor pan, aft of the headers.



Our newest fabricator Zach stepped up and mapped out the curves with 3" mandrel bends, cut them to fit, tack welded them together, then added 3" V-band flange to the ends.



These collector bends were finish TIG welded, the welds inside were sanded smooth, and these were then welded to the ends of the collectors.



With the headers reinstalled one last time to check fit they were removed, and I took them to be ceramic coated along with the re-used headers from the CTS-V.



The difference was amazing! The old Caddy headers look brand new, and even the new "raw stainless" LS550 prototypes look like a million bucks. The entire exhaust is getting coated when it is complete. We might still DEI heat wrap some areas of the exhaust that are close to things we don't want to get hot, but for the most part this coating will drop lower underhood temps all on their own - while looking very sharp. This coating is very durable (we've used this place / this coating on exhausts before) and if it gets covered in oil it can be shined up again with a Scotch-Brite pad or steel wool.

FITTING THE MUFFLERS

This step shows how Zach fitted these mufflers to the rear of the car, starting in August 2021. Sadly the two types of muffler mount bushings were SUPER delayed in getting here and this pair of mufflers isn't 100% mounted yet - just held in place by straps. Which is holding up the rest of the exhaust, but within days of me writing this these delayed parts will arrive...



Zach understood where and how I wanted these mufflers mounted and he pushed through the obstructions to make it happen. The initial opening in the rear trunk wall (above left) was done with a 4" hole saw, leaving an air gap around the 3.5" tubing diameter. The second hole (above right) was on a weird slope and angle, but was cut the same way - just with a lot more effort.



These two cuts allowed the back of the muffler to tuck up close to the back wall of the trunk, and then the tips can make it all the way through...

EXHAUST TIP SURROUND

Now I will admit this part is seems a little "showy", but it was necessary to make the exhaust tips exit high in the chassis, next to the license plate frame. There is also a practical reason for this.



We have done unusual muffler tip placements before, in order to squeeze the biggest mufflers under a car - like on this C5 above. We ditched the normal double 90 deg bends the C5 uses and added Magnaflow mufflers 2x as large as the OEM units by taking this unusual path (and removed two 90 deg bends and added one 45 deg on each side). This routing necessitated side exit tips, and these stainless steel heat shields (which are brushed finished, and easily cleaned when they get a coating of exhaust soot). One of the best sounding C5s I have ever heard, and quiet. Picked up 25 whp with this exhaust change, too!



On the LS550, to get the even larger 5 x 11 x 22" case Magnaflows to fit between the rear axle the bumper cover AND be above the future rear diffuser top plane, they need to start low and angle upwards (we will cut the back of the bumper cover at the trim line below the license plate frame).

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