GMR Supercharger Kits
It's something we've wanted for years and it's finally happening. Powerful, reliable, and attainable supercharger kits for the V8 Vantage.
That’s right. GMR’s supercharger kits are finally coming to America.
I first drove the company’s development car during a trip to England last year. I loved the thing and wanted to bring the company’s products to the US. They’re understandably very protective of their products and have only allowed them to be installed on cars when they check the cars and install the kits themselves. That’s often a non-starter for potential customers an ocean away, so GMR doesn’t have much reach beyond England and Europe.
Even so, I wanted the product not just for my own car, but also to offer through Redpants. GMR knew I was serious when I returned to England for another meeting with them, this time bringing a videographer along. Not only did I want to sell their products, but I’m so eager to do so that I was investing a lot of my time and money into helping promote them as well. Customers will rarely shell out large sums of money for a product that they don’t know much about, so I wanted to make everything as clear as possible. The video was a way to get that started, and the rest of this article will help clarify the rest.
GMR's supercharger kits raise the 4.3L V8's engine output from 380 bhp to 573 bph. That's more than a V12 Vantage S. Meanwhile, torque is increased from 302 lb/ft at 5000 rpm to 445 lb/ft at 3500 rpm. That's not only a huge increase in torque, it also reaches peak torque a whopping 1500 rpm sooner than the standard engine. Horsepower is a linear climb all the way to the 7300 rpm redline and the torque curve is flat from peak to redline. The supercharger kit is also available for the 4.7L V8 engine, and produces even more peak power due to the larger engine size.
All those numbers means the car can go from 0-60 mph in under 4 seconds and it’ll pull hard all the way to the car’s top speed. One driver had reported back after a test session that he hit the rev limiter in 6th gear. It had almost surprised him because the car was pulling so hard all the way until redline in 6th, at which point he realized he was out of gears to climb through.
Despite the relentlessness of it, power delivery is smooth and predictable. The V8's characteristics stay the same, but there's so much more power when you want it. There's no sudden rush of power like you'd get from a large turbo. You don't have to worry about the car flying out of control. Torque comes on like a solid wave as you put your foot down and the huge sweep of horsepower rushes you all the way to redline. It’s the same wonderful V8 engine Aston Martin put in the car, but there’s so much more of it.
Something many people don't realize is that the supercharged engine is actually easier to control than the factory naturally-aspirated engine in some ways. The extra power lets you drive the car without having to rev the engine so much to get the power that you want. In normal driving around town, you’d never know the car is supercharged. It feels completely natural. But when you get on it… the thing flies.
The scariest thing about getting all this power out of our engines is not knowing what it's doing to our engines. In general, the more power an engine puts out, the more stressed it is. The more stressed the engine is, the shorter its life will be.
GMR knows this is a huge concern and they've done literally years of testing to ensure reliability is still maintained. Their development car had its supercharger installed when the car had only 9500 miles on it. It now has around 125,000 miles on the clock. That's well over 100k supercharged miles, which is more than most completely unmodified V8 Vantages have. They've done massive amounts of research and development to ensure their hardware is solid and their tuning is flawless.
The engine doesn't get much stress with the supercharger kit. Boost is only ~6 psi and peak cylinder pressures are only increased by 10%. Even the redline is kept at the factory-specified 7300 rpm as an added safety measure.
I have the redline in my grey V8 Vantage raised to 7700 rpm - a special request I made to VelocityAP because I kept hitting the factory rev limiter during track days and wanted the extra bit of wiggle room for those rare but key moments when I'd need to stretch my engine a little further. I’ve been incredibly happy with the result, and my 4.3L V8 engine now has both the muscle and flexibility to perform beautifully on the track.
I asked Graham, GMR's chief engineer, why they don’t raise redline when tuning for the supercharger.
"There's no reason to," he said. The supercharged engine has so much power and torque on tap that raising redline isn't needed. Doing so would only add more stress to the engine and present an unnecessary risk.
In fact, in normal driving the engine is less stressed with the supercharger because you don't have to rev it so much to get it to do what you want. An added bonus to that is improved fuel economy. And, bonus, GMR's supercharger kit results in drastically lower emissions compared to an unmodified factory-spec car.
For the first time ever, GMR’s supercharger kits are coming to America. They’ll be available soon through Redpants! The kits will include everything that’s needed for installation, and we’ll even have guides showing how to do it. Professional installation is required. There are certain things that must be done a certain way, and making mistakes when supercharging an Aston Martin engine can be extremely costly.
The kits will include the supercharger, intake manifold, water tank, lines, belt, crank pulley, tuning module, and everything else needed. Once installed, the tuning module will be used to send tune files back and forth between the customer and GMR.
The price will vary depending on which year V8 Vantage you have. For example, newer cars that have catalysts in the headers (MY10.5 and up) will need new headers as the factory ones have catalysts that won’t survived the supercharged exhaust flow.
GMR also require their own catalytic converters be used. They can’t guarantee cats from other brands will be able to manage the exhaust flow of the supercharged engines, and they’ve encountered failures of non-GMR cats in testing. Their cats are made specifically to handle their supercharger kits. Even on their own, their cats have been tested and show a 25 hp increase in power compared to the factory cats, so they’re definitely worthwhile to get regardless.
An upgraded clutch is HIGHLY recommended. I doubt the factory single-plate clutch will survive long when subjected to the greatly-increased torque that the supercharger provides, so you should upgrade your clutch at the same time as installing the supercharger. I recommend the clutch package from VelocityAP, which uses the clutch from a V12. Since it’s made for the V12, the clutch will be very well suited to the supercharged V8’s power output. The clutch package also includes a lightweight flywheel, which will improve throttle response.
Professional installation in required and expect it to take 3-4 days.
Use and maintenance
The only routine maintenance needed for the supercharger kit is filling up the water tank. Water is used at a rate dependent upon your driving style - the more you flog the car, the more you drain the water tank. In general, one tank of water will last through two tanks of fuel.
Want to know more about water injection? Check out this video.
An indicator light is included with the supercharger kit. The light is mounted inside the cabin of the car and turns on to warn the driver when the water tank gets low. If the water runs out, the supercharger will disengage. You’ll basically be driving a naturally aspirated (non-supercharged) V8 Vantage again. Once you fill the tank back up, the supercharger will reengage and you’re back to normal.
The water injection system includes a pair of water filters that ensure the water going into the engine is as clean as possible. These need to be replaced once per year - just add it to your routine maintenance schedule and swap them out when you do your annual oil change.
The supercharger belt will need to be examined and replaced if necessary every 24,000 miles or 3 years, whichever comes first.
Additionally, the oil within the supercharger itself needs to be replaced…. every 250,000 miles… yeah, it’ll last a quarter of a million miles. Not too shabby for maintenance, is it?
Lots more info including pricing, package contents, and installation guides coming soon!!
Is the supercharger kit safe and reliable?
Yes. GMR have put years of testing and development into their products. Their own development car has been supercharged for 115,000 miles and counting.
Does the supercharger kit include an intercooler? How is the intake charge cooled?
No, this kit does not use an intercooler. Rather, it uses water injection to cool the intake charge. An added benefit of water injection is that it helps keep the engine’s internals clean.
What happens if the water tank runs dry?
There’s a level sensor inside the water tank. If it gets too low, an indicator light will warn the driver. When the water tank is empty, the supercharger will disengage and the engine will act as a naturally aspirated engine so you can carry on driving. Once the water tank is refilled, the supercharger will reengage.
What kind of water should i use?
The water injection system uses a pair of water filters to ensure the water is clean before being injected into the engine, so you can use normal tap water if you want. However, I recommend using distilled water to help prolong the life of the filters and ensure the water going into your engine is as clean as possible.
What maintenance is required?
Consistently: Add water to the water tank as needed. A single tank of water will generally last around two tanks of fuel, but best practice is to check the level and top it off as needed to ensure it never runs dry.
Every 1 year or 10,000 miles: Replace the water filters.
Every 3 years or 24,000 miles: Examine the supercharger belt and replace if necessary.
Every 250,000 miles: Replace the supercharger’s internal oil.
Will the supercharger kit change the way my car sounds?
No. The supercharger is part of the intake system, so it has no effect on the sound of the exhaust. The “whine” that many superchargers have is not found in this one, so the intake sound is not changed, either.
Are these supercharger kits C.A.R.B. compliant?
The two primary concerns of CARB testing are exhaust emissions and fuel economy. MOT* testing has shown a drastic reduction in emissions, and real-world testing shows greatly-improved fuel economy (in general, a 20% increase in MPGs). Although I’d expect GMR’s supercharger kits to pass CARB testing with flying colors, that is an expensive and time-consuming process. We aren’t ruling out having it done in the future, but we do not have any immediately plans for CARB certification.
*MOT is the Ministry of Transportation, the British version of the US’s Department of Transportation (DOT).