The tale of C4 Corvette ZR-1 and the LT5 engine

Source: Drdisque via Wikimedia Commons CC BY 2.5/Shrunk from original size

OHV history

Overhead Valve (OHV), or otherwise known as 'Pushrod', is nothing new to the automotive world. The tech where the in-cylinder block camshaft actuates the in-cylinder head valves with a pushrod has been around since 1898 thanks to a man by the name of Walter Lorenzo Marr who was building a single cylinder trike with the OHV valvetrain. After a short stint at Buick as their Chief Engineer from 1901-1902, Marr founded his own car company, Marr Auto-Car Company, in 1903 and proceeded to dish out a handful of automobiles with OHV engine before returning to Buick in 1904.

Corvette line-up anomaly; in come Lotus

Marr's creation somehow survives until the present day on some sports cars. One of the sports car that still carries Marr's OHV tech is Chevrolet's 2 door sports car, the Corvette. From the C1 Corvette to the current C7 Corvette Stingray, OHV remains as the mainstay of Corvette's engine line-up, with one exception though. The C4 Corvette ZR-1 remains the only Corvette to buck the Corvette's OHV trend.

Source: Steven N. Severinghaus via wikipedia CC BY-SA 3.0

Manufactured from 1990-1995, the car was powered by the all aluminum Lotus-designed 5.7 litre LT5 V8 with Dual Overhead Cam (DOHC) setup. Yup, it's completely unique to the rest of Corvette's engine line-up, going with 32 valves DOHC setup over the typical 16 valves OHV. This all started in 1986 when Chevy's parent company, General Motors (GM), bought Lotus, a UK-based company specialising in performance car manufacturing and engineering consulting. GM's target was to create a production sports car that will blow off the doors of the competition, or in short, the fastest production sports car. Of course, this wasn't going to be an easy start for the GM-Lotus engine project.

Tough beginning

GM discovered that the engine was rather finicky, in that it needed special assembly. This put GM on a backfoot in finding an assembly plant specific for the LT5. All hope was not lost as Mercury Marine, a specialty engine builder from Stillwater, Oklahoma, stepped in to assemble the engines and shipped it back to Bowling Green, Kentucky Corvette plant where the ZR-1 was being assembled. Thanks to Mercury Marine's generosity, the legendary LT5 was born along with the C4 ZR-1.

One heck of an engine for its time

The LT5 was based on the L98 V8 that powered the standard C4 Corvette. Owing to GM's target in creating the fastest production sports car, the L98 didn't fit the bill for the ZR-1. The 5.7 litre 250 hp 16v OHV L98 was later replaced by the more powerful and sophisticated-for-its-time LT5 V8 with the same 5.7 litre displacement, but with 32v DOHC setup.

Together with unique air management system that can shut off 8 of the 16 intake runners and fuel injectors at part throttle, the LT5 was good for a brilliant 375 hp from 1990-1992 ZR-1. ZR-1 manufactured from 1993-1995 was to enjoy a power hike to 405 hp courtesy of changes to the cam timing and more efficient engine porting.

It's all in the record

The performance of the LT5 didn't just award the C4 Corvette ZR-1 with a blistering 0-62 mph time of 4.4 seconds, but also enable it to set 3 world endurance speed records:

1. 5000 km at 282.778 kph
2. 8000 km at 279.69 kph
3. 24 Hours Endurance at 283.059 kph for 6793.453 km

Unfortunately, its existence is short-lived

Thanks to factors such as increasing production cost and dwindling sales, the C4 ZR-1, along with the LT5, had a rather short lifespan as GM pulled its plug after model year 1995. In total, 6939 C4 ZR-1 were ever produced by GM.

  

2018 Kia Stinger launched!

Source: Kia

Kia has finally taken the wraps off of their 4-door sports sedan, the 2018 Kia Stinger. It's loosely based on the Stinger GT4 concept displayed at the 2014 Detroit auto show with additional 2 doors.

Powering the Stinger are 2 choices of engine: 2 litre Theta II turbocharged 4 cylinder (255 hp at 6200 rpm and 353 Nm from 1400-4000 rpm) and the more powerful 3.3 litre Lambda II twin turbo V6 (365 hp at 6000 rpm and 510 Nm from 1300-4500 rpm). Power is sent to either the rear wheels with mechanical limited slip differential or rear-biased all wheel drive with Dynamic Torque Vectoring Control. 

If you're looking for a manual-equipped Stinger, don't read any further because the Stinger only comes with an 8 speed automatic transmission. I guess Kia only let the car do the heel toe downshift😅!   

On the handling front, the front axle will ride on MacPherson strut, while the rear axle will make do with more sophisticated multi link suspension. Also included is Kia's first Dynamic Stability Damping Control, an electronically adaptive damper. Interestingly, the chassis development is led by former BMW M man, Albert Biermann. Let's see if Kia's new sports sedan will outmuscle the BMWs around corner-galore Nordschleife (apparently Kia has been tuning the chassis around the legendary 'Green Hell'). 

As always, safety first! The Stinger is equipped with Autonomous Emergency Braking, Lane Keep Assist, Rear Cross Traffic Alert and Blind Spot Monitoring System. Tyre sizes vary depending on engine choices: V6 (225/40R19 front, 255/35R19 rear); 4 cylinder (225/45R18 all-round). Also, if you choose the V6, the braking system is courtesy of vented Brembo disc with 4 piston caliper front and 2 piston caliper rear. 

Why a hybrid Ford Mustang is inevitable?

You opened your favourite automotive news portal to feed yourself with attention-worthy news pieces. You scrolled down the long list of articles and if you happen to be a diehard fan of Ford Mustang, your jaw dropped. Your heart sank. You feel like screaming 'SACRILEGIOUS!!!' at the Blue Oval thanks to the news headlines that sounds roughly like this: Ford Mustang to join the hybrid bandwagon by 2020. 

"Gasp! A muscle car brute joining the ranks of Prius?! You gotta be kidding me!", I heard you exclaiming. Well, as much it's disheartening the Mustang is going to zap its V8 with a good dose of electric power, this isn't necessarily a bad thing and in some way, necessary. Here are reasons why:

Even high-end sports car brand is going hybrid route

Hybrid technology is no longer exclusive to run-of-the-mill, fuel conscious family wagon. Ferrari is contemplating on hybridising their entire model lineup by 2019. BMW performance arm, the BMW M, is also looking to complement their M cars with hybrid technology.

If that's not enough, Mercedes and Aston Martin are dishing out their own street-legal hybrid hypercar. 

Starting with Mercedes, their performance division, AMG, has confirmed their hybrid Mercedes AMG hypercar with F1-based (yep, it's the same engine found on Lewis Hamilton and already-retired Nico Rosberg's F1 car) 1.6 litre turbocharged V6 hybrid, though reportedly it might be larger in capacity as it's not subjected to motorsport regulation.

Joining Mercedes in producing insane street-legal hybrid hypercar, Aston Martin has team up with their partner, Red Bull Racing F1 Team, to develop their own version of the Mercedes hypercar, the AM-RB 001. This monster hypercar will get its power from a naturally aspirated V12, with extra power boost from F1-derived hybrid system.

All these leads to my next point...

Hybrid tech actually improves performance potential

Combine the internal combustion engine with electric motor and you have a recipe for a potentially tyre-shredding performance. I am going to use Ferrari LaFerrari as an example. 

The Ferrari LaFerrari's 6.3 litre naturally aspirated V12 outputs around 789 bhp. Supplemented by the 161 bhp HY-KERS electric motor, the only hybrid Ferrari production supercar generates a whooping total output of 950 bhp, good for propelling it from 0-62 mph in less than 3 seconds. Thanks to the hybrid powertrain, the LaFerrari is the most powerful  road-going Ferrari the brand from Maranello has ever produced, surpassing the F12 Berlinetta (730 bhp) and F12 tdf (770 bhp).

With LaFerrari's staggering performance figure in mind, I can't think of a reason why Ford wouldn't hybridise their iconic Mustang muscle car. If hybrid has granted LaFerrari the most powerful Ferrari road car crown, surely adopting hybrid tech is going to make the Mustang even more potent than the previous iteration of the Ford's pony car.

Of course, performance is not the only reason for going the hybrid route.

We have to go green yo! Coz tighter emission standard

This is by far the most crucial reason for sports cars to go hybrid. With emission standard getting tighter, this is becoming a necessity. More and more hybrid sports cars are hitting the roads, such as BMW i8, Koenigsegg Regera, second generation Honda NSX, out-of-production McLaren P1, Ferrari LaFerrari and Porsche 918 Spyder. These hybrid sports cars exist to give enthusiasts the performance they crave without getting under the environmentalist's skin.  

So implementing hybrid should be a win-win for the much loved Mustang. You still get a Mustang with tyre-smoking performance with lower emission to boot. Despite the benefits hybrid technology offers, there are several challenges to overcome.

The Challenges

Weight

Obviously, adding electric motor and battery pack do add weight, a complete opposite in performance enhancement. When Porsche was developing the 918 Spyder, their test driver and legendary rally champion, Walter Rohrl, was initially sceptical of it being a hybrid, as such approach will add weight (the 918 Spyder won him over eventually). 

With the current S550 Mustang weighing around 1600-1720 kg, implementing hybrid is going to make Ford's pony car weigh even more unless if they think like Koenigsegg.

Complexity

More parts, more stuff to break, higher expanses. Indeed, hybrid is one heck a complete headache-inducing piece of contraption to reap the performance and emission benefits. 

According to Mark Fitzgerald, a senior automotive analyst from a market research firm, Strategy Analytics, hybrid cars require additional components that you won't find in conventional cars such as "electric motors, electric inverters and converters, high-voltage batteries, electronic control units, semiconductors and sensors". Well, this is not entirely surprising as hybrid needs extra bits of stuff to make them function.

Conclusion

The idea of hybrid Mustang is not entirely a bad thing. Yes, there are camps that will go up in arms at the idea, but given the challenges that automakers are facing (emission being one of them), the wave of hybridisation is more or less unavoidable. All I can say is welcome to the future folks! 

         

If I were Mini, this is how I propose the third gen Mini John Cooper Works GP powertrain be

So, Autocar reported that the third generation John Cooper Works GP is in Mini's bucket list. Hurrayy!! The catch is you may have to wait a little longer, as forecasted by Autocar, "closer to the end of the decade", which might probably be around 2020. This hot hatch has been historically known to be the end-of-chapter model to its regular hatch counterpart. 

Now let's cut to the chase. Befitting this post's headline, the powertrain will be the thing I am zooming into...with my own twist.

The 2013 Mini John Cooper Works GP is motivated by a 1.6 litre turbocharged direct injected 4 cylinder mill which, thanks to a bump in compression ratio, boosts output to 218 hp. Power goes to the pair of front wheels via the sole 6 speed manual transmission. 

Now, I would like to get a bit cheeky with the powertrain layout. It's common knowledge that Mini is owned by the BMW Group. If I were in Mini's shoes, here's what I would do to spice up the third gen John Cooper Works GP. I would dispose of the current 4 cylinder engine for BMW's 3 litre turbocharged inline 6 that makes around 330 hp and channel those power to the rear wheels through a stick shift without any fancy auto rev match feature (I would heel toe myself thank you). The result? Voila! An FR Mini John Cooper Works GP, along the lines of the 2015 BMW M135i. 

Yea...I am a bit cheeky with the power figure (330 vs 322 on M135i). Not that much difference, though I would figure the John Cooper Works 1179 kg (without factoring the extra weight from the extra 2 cylinders and propshaft) vs the M135i 1520 kg is more than enough to offset the minute power difference. This should give Munich a run for its money. 

How much would my hypothetical Mini John Cooper Works GP weigh once the 6 cylinders and propshaft's weight is counted? It's anyone's guess. Maybe still lighter than the M135i? Or close to M135i's figure?

What do you think of my hypothetical Mini? Do sound off in the comment section!