Acceleration, We Hardly Knew Ye

What a difference a little ring of steel can make.

The second-hand differential we had purchased ended up being one of the least costly acquisitions involved in Project Hoondy’s very expensive rear end rebuild, yet the switch to a 4.181 final drive ratio was easily the most dramatic change to the car:

There’s now a real urgency in the way Project Hoondy gains speed. First through third gears are gone in a flash; you’ll find yourself deep into fourth and well on your way to 100MPH before the strength of the acceleration even begins to let up. Third and fourth gear are now instruments of terror and even fifth gear has been upgraded from a distant also-ran to a deep well of accelerative forces.


Which isn’t to say that the short final drive’s supporting cast of fresh components aren’t a major part of the new driving experience. They simply work together so seamlessly that they all melt away, leaving only a demonic throttle pedal as any clue to the driver that they even exist at all.

That said, after living with the changes for a while the nature of at least some of the individual components have managed to stand out to us. First up after the nutty final drive ratio is easily that carbon fiber driveshaft. Before its addition, there was always a sense of delay between laying into the gas and torque being delivered to the rear wheels. You could always feel that old multi-piece driveshaft winding up, stealing away power that rightfully belonged to the long-suffering rear tires. Likewise, suddenly lifting off the gas would result in a lurching feeling as the direction of power delivery reversed

No longer! It now feels as if the engine is connected directly to the rear wheels, with no mechanical contrivances like gears or driveshafts existing between them. While this change has done much to make the car more of a ferocious performance machine, it also has had a surprisingly positive effect on ride comfort. When driving the car gently in traffic you are very light on the gas, frequently transitioning from on-power to off-power. Said transition is now absolutely seamless and buttery smooth, contributing to an unexpected sense of refinement.


In fact, despite the drastically more solid rear end the car is no more raucous than it was before (demonic throttle pedal notwithstanding). There are no intrusive clunks, grumbles, or road noise emanating from the rear of the car. We attribute this to the OEM quality of the Genesis Sedan subframe and the remaining compliance of the urethane-filled rubber mounts. Invasive of a procedure as it was, we highly recommend the Sedan subframe swap over the after-market alternatives for this reason. It’s a have-your-cake and eat it scenario where good road manners meet bomb-proof durability.


Bomb-proof hardly being an overstatement in this case. The drivetrain now feels positively indestructible. Shift as fast as you want, lay into the throttle as deep as you want, clutch-kick as hard as you want, Project Hoondy does not have one single fuck to give. This is how you build a driver’s car: a modestly potent engine connected to an indefatigable power transfer system. The driver is left to wring the car’s neck with reckless abandon, so long as you don’t crash it there’s nothing you can do to hurt this thing.

And with that satanic gas pedal, the car just eggs you on. It is difficult not to conjure up mental images of the ultimate BDSM enthusiast. No punishment is too severe, no scenario is too outlandish. Whatever perverted activity your twisted little mind can come up with, they will always answer the same way:

Give me more!

Normal performance cars just don’t feel this way, no matter how hyped-up they might be. Cars like the Mustang GT Track Pack have at least a distant sense of fragility to them. Don’t abuse them too badly or you’ll break something expensive. Their impressive engines are simply not supported by an equally impressive system of containment. It makes sense as to why: such cars are largely sold on the back of their performance metrics. While an over-built rear end like ours feels incredible from the driver’s seat, it contributes virtually nothing to the numbers game. Building a Mustang to be as resolutely solid as Project Hoondy would drastically increase its purchase price only to give near zero increase in buff-book bragging rights.


The OEM home of this philosophy is probably Porsche. When comparing their products to equally-priced offerings from other car-makers they always seem to come up short in the horsepower department. Yet, ask the Chris Harrises of the world and they’ll say they wouldn’t have it any other way. The benefits are also proved out in the giant-slaying nature of those cars. They always seem to do more with less, turning in lap times and driving experiences that are far more dramatic than the raw power output of their engines would suggest.


While Project Hoondy is not yet complete enough to be a track weapon, you no longer have to squint too hard to see the end-game. Dump the clutch, mash the gas, and it makes a truly compelling argument.

However, the car has also become imbalanced, probably the most it ever will be.

Front axle grip was never the Genesis Coupe’s strong point, and that fact has become painfully obvious after this latest modification. So long as you are on the gas the car is happy, but as soon as the weight transfers to the nose it feels significantly less sure-footed. Limited bump-travel, narrow 225 section front tires, and modest brakes all conspire to sap away the driver’s confidence when decelerating and/or turning.


So for the next set of modifications our attention will finally focus on the front of the car. Based on our early ownership of our Genesis Coupe we really thought we would get to the front sooner, but we have since learned that true high-quality modifications make a larger impact on the overall driving experience than one might assume. For example, we absolutely never expected our Cusco RS limited slip differential to change the car’s steering feel so dramatically. Such improvements have nibbled away at our dissatisfaction with the car’s front end, but there’s no getting away from it now.


First up shall be brakes. With over 106,000 miles on the clock, Project Hoondy, almost unbelievably, is still wearing its original brake pads and rotors. Yes, really. We chalk their longevity up to our habit of consistently down-shifting and engine-braking in traffic, but even as easy as we are on them their life is nearing its end. With our drastically improved acceleration, an upgrade to the larger Brembo brake calipers that were available on the Track Pack is definitely in order.

After that come front suspension arms and some kind of coil-over package. Then, finally, a go at the engine? Only time will tell, so stay tuned to Project Hoondy!

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