The S550 (and now S650) Mustang GT are one of the most popular platforms on the road in America, and for good reason. With up to 450hp out of the box, it's not only quick but a ton of fun to race. What would make it more fun? Turning it into a 8-second drag racing street car. How? That's what Lethal Performance is here for. From exhausts to superchargers and everything in between, we'll show you what you need to get your Mustang GT hitting 8s in the quarter mile in no time.
How To Build an 8-Second Mustang | A guide from Lethal Performance
We had a 2018 Mustang GT named Project Goldmember that was a BLAST to race and drive. Not only did it cruise to work with no issues, but it also clicked off mid-8-second quarter mile passes. Jared went 8.64 @ 157mph, which was even more impressive because our 2018 Mustang GT was the first Lethal Performance car that we've had that Jared decided to get behind the wheel at the drag strip--no more hired guns here.
We used all of our product testing, dyno runs and track times from Project Goldmember to put together this "Quick Start Guide" to building your own 8-second Mustang GT. Let's f*cking go!
Sections (aka your Shopping List):
A high-performance fuel system is crucial for delivering the necessary fuel to support increased horsepower and torque. Lethal Performance offers a range of fuel system upgrades, including fuel pumps, injectors, and fuel rails, designed to maximize fuel delivery and ensure optimal engine performance under high loads.
For an 8-second build you will most likely be around 1000rwhp, which you'll need something like the Lethal Performance / DivisionX Triple Pump Return Style Fuel System to support. The system is backed by (3) high flow Walbro pumps, comes with plug & play wiring and is a complete setup including fuel rails.
Click here to find out which fuel system is right for your setup with our Lethal Performance / DivisionX Fuel System Guide.
You will also need a set of fuel injectors, especially if running on E85 which requires more fuel flow. While we ran the Injector Dynamics ID1300cc injectors in Project Goldmember, you can also go bigger with a set of ID2000 injectors or a set of 1440cc or 1650cc FIC fuel injectors.
You can order most supercharger kits as a "Complete Kit" that comes with tuning preloaded from the manufacturer, and a lot of times that tuning is great (we made over 800rwhp in our 2024 Mustang GT on a stock Whipple tune). However, when you begin to add other mods like headers, fuel system, etc. and push the boost beyond stock levels, a custom tune becomes necessary to make sure everything is in working order.
Custom tuners, like many other aspects of Mustang performance, are not ‘one size fits all.’ There is no “best supercharger” or “best exhaust”, just as there is no “best tuner.” There are, however, awesome tuners and there are crappy tuners. We offer the best of the best here at Lethal Performance via The Tune Shop. Whether it's a tune by Ken Bjonnes at Palm Beach Dyno, Lund, Jr. at Lund Racing, a Tunemaker tune from Shoemaker Performance, they will have your build running solid.
A supercharger is the heart of any high-performance build, delivering massive amounts of boost pressure to increase horsepower and torque. Lethal Performance offers a variety of supercharger kits from top brands like Whipple Superchargers and VMP Performance, allowing you to choose the perfect setup for your goals and budget.
We ran a Gen 5 3.0L Whipple Supercharger in Project Goldmember, our 2018 Mustang GT, and went mid 8s without even maxing out the supercharger (that was also using a pre-production setup!). We may be partial to Whipple Superchargers, but it's for good reason. Whipple stays at the forefront of technology, not only improving on new models but carrying those awesome innovations in cooling & horsepower down to the previous models as well so that even if you aren't working on the latest and greatest application out there, you're still getting the best bang for your buck when installing their latest generation of Whipple Supercharger.
Click here for a quick overview on our best selling supercharger brands.
Enhancing exhaust flow is key to unlocking additional horsepower and achieving a more aggressive exhaust note. Lethal Performance's selection of high-flow exhaust systems and headers improves scavenging efficiency, reduces back pressure, and adds a distinctive growl to your Mustang GT's soundtrack. This is especially true when supercharging your Mustang.
We installed and ran a set of Kooks longtube headers on our 2018 Mustang GT. Kooks are made here in the USA from high quality stainless steel and have no fitment issues whatsoever. We have also run American Racing Headers and Stainless Works in previous cars with 0 issues.
We now even offer our own set of longtube headers for your 2015-up Mustang GT made by Kooks. They are a 1 7/8" primary and include a set of competition connection pipes. Click here to check them out.
Behind the longtubes, you'll want to pick out a cat back or axle back exhaust setup. This will add a more aggressive note and open up the exhaust more (especially if you choose a cat back with a resonator delete to get rid of the stock "suitcase" resonator). We ran a Kooks axle back on our 2018 Mustang GT but all of our axle back offerings from best selling brands like Corsa Performance, AWE Tuning and more will support your horsepower and sound awesome.
Upgrading your Mustang GT's transmission is essential for handling the increased power and torque generated by high-performance modifications, whether it's a manual or an automatic. Lethal Performance offers transmission upgrades, including clutches, torque converters, and shift kits, to ensure smooth and reliable power delivery during aggressive launches and shifts.
MT-82 Manual Transmission?
The first upgrade for any manual transmission is usually a high performance clutch setup. While the stock clutch offers great drivability, chances are it's not going to survive an 8-second pass a the drag strip. For roughly 1000rwhp, a twin disc setup is the best option.
You can check out the McLeod RXT and RXTHD offerings for a ceramic compound disc setup. Another option is the LPXHD, exclusive to us here at Lethal Performance and made by McLeod, which is constructed with Kevlar discs.
Need to upgrade the entire transmission? We offer fully built MT82 transmissions from Calimer Transmissions.
10r80 Automatic Transmission?
The 10r80 automatic transmission is a fickle fellow. Some people encounter issues with their 10r80, however we were able to race with ours many times and had great success. We installed a McLeod Friction Plate & Steel kit on our 10r80 immediately, paired with a Circle D 10r80 torque converter. These two components not only help strengthen your transmission but ensure better launches and driving at the track.
Another option available now is a fully upgraded 10r80 transmission from our friends over at RSA Race Solutions, who have built some of the fastest 10r60 and 10r80 vehicles out there. Check out their 10r80 transmissions here.
Strengthening your Mustang GT's driveline components is crucial for handling the added stress of high-power applications and the force of drag racing. Lethal Performance provides upgraded driveshafts, axles, and differential components to improve traction, reduce drivetrain losses, and enhance overall durability.
Halfshafts / Axles
We managed to snap our stock half shaft the first time we ever went to the track with our 2018 Mustang GT, when it was bone stock! Since then, we've made it a point to upgrade the axles in every vehicle before we hit the drag strip. Driveshaft Shop and G-Force are the top manufacturers for halfshafts for the S550 and S650 Mustang GT, with options rated up to 2000hp.
Driveshaft
The driveshaft may not be a common broken piece, but it's one you certainly benefit from upgrading. Replacing the stock, rubber mounted 2-piece driveshaft with a new 1-piece aluminum or carbon fiber driveshaft not only sheds weight but also increases power holding ability and drivetrain response.
We offer (and have used) aluminum and carbon fiber driveshafts for both manual and automatic transmission Mustangs from Driveshaft Shop and QA1.
Achieving 8-second quarter-mile times requires more than just raw horsepower; it demands a well-tuned suspension system to maximize traction and stability. Lethal Performance offers suspension upgrades to fine-tune your Mustang GT's launching for optimal performance on the track.
There are a LOT of suspension components available for the S550 and S650 Mustang, from bushing replacements to entire suspension packages. In an IRS car like the S550 and S650, there are a couple of issues to address. The first issue is that the entire cradle assembly will move/rock. The factory cradle bushing has a small lip on the top which is a limiter. On our 2018 Mustang, when we launched it at the track, this limiter was hitting the chassis, leaving a witness mark on the body from the cradle moving (see image).
Another issue to address on the IRS is the movement of the differential itself within the cradle. The factory bushings have small metal alignment nubs built in. On a factory car, these protrusions are barely visible (or not visible at all) however on our S550, the passenger side was sticking way out and the driver's side only slightly out. This tells us that the diff moved enough to compromise the clamping force of the bolt & also stayed seated in a diagonal position. Next, we looked at the rear differential bushings & bolts. It was clear here, also, that the diff had moved as the bolt on the passenger side was sitting much higher on the bushing than it was on the driver's side.
Our favorite setup to address all of these issues, and what we used on our 8-second 2018 Mustang GT, is the Lethal Performance / BMR Suspension Bread & Butter Suspension kit. We went a 1.27 60' with that setup! Since the creation of the Bread & Butter Kit, we've also since released the updated Bread & Butter II Suspension kit. Both will get you the 60' you want.
Want more info?
Click here to learn about all the components of our BMR Suspension packages and why you need them.
Click here to check out the Bread & Butter II package components.
A high-performance set of wheels and tires is essential for putting the increased power to the ground effectively. Lethal Performance offers a wide range of lightweight wheels and high-grip tires designed to improve traction, reduce rotational mass, and enhance overall performance during high-speed runs. Your best option when chasing an 8-second time slip is what is called a "Drag Pack" which is a set of drag racing wheels, usually with skinny wheels and tires up front, and a wider set of wheels in the rear wrapped in either drag radials or slicks.
Wheels
Why drag wheels? Besides coming [usually] in smaller diameters and larger widths to accommodate meatier tires, drag wheels often offer large weight reduction. The weight reduced is unsprung weight, which is weight that is not supported by the suspension/springs. This unsprung weight is also what your suspension is forced to control so that the tires remain in contact with the surface and provide traction. The less unsprung weight, the easier it is to control. A general rule is that for every 1lb of unsprung weight you remove it is equivalent to roughly 4lbs of sprung weight.
Here at Lethal Performance we have a wide variety of lighter drag racing wheels to choose from, from our Lethal Performance LPS5 drag wheels to Forgestar Wheels to Weld Racing wheels. It is important to note that some of the 17" and smaller wheels will not fit with the larger Brembo or big brake upgrade kits that many S550 and S650 Mustangs have. We do our best to notate which wheels will & will not fit on your application. If you do have any questions, just give us a call.
Tires
Choosing a tire can be intimidating. Different compounds yield different results, not just at launch but even at the top end of the track (slicks have a certain sway to them). Most cars will do best with a good drag radial tire on the rear, with the Mickey Thompson ET Street R being one of the most popular. These tires, however, will not perform well in regular driving conditions like rain and will not last as long as a standard radial due to the softer compound. They will provide you with some awesome grip at the track, though!
To check out some of our most popular drag racing tire options here at Lethal Performance and learn about their differences, click here.
Lastly (but certainly not least), upgrading your Mustang GT's brakes is crucial for safely controlling the increased speed and power of a high-performance build. Lethal Performance provides brake kits, including rotors, calipers, pads, and brake lines, to improve stopping power, reduce brake fade, and enhance overall braking performance under extreme conditions.
On our 2018 Mustang GT, we installed a set of the Baer Drag Race 2.0 brake kits on both the front and rear. Not only do these brakes look awesome (available in a wide variety of colors) but they also save you more of that unsprung weight (discussed earlier). Performance Pack cars can save up to 86lbs with the Baer SS4+ 2.0 Drag Race Brakes! Click here for more info on the Baer SS4+ 2.0 Drag Race Brakes.
We hope this quick start guide helps you to build YOUR dream 8-second (or however fast you want to go) Mustang. If you have any questions, give us a shout! #teamlethal