Posts By: Eric Hsu

Ken sent me a link to some cool videos from 1981 on the Cosworth DFV Formula engine. These are pretty interesting:
That piston forge you see in the beginning of this video is still in use today at Cosworth UK. I think this was when the DFV was still trying to hold off the turbos.


This video has a pretty good explanation of spring surge and valve float. It illustrates what can happen when somebody tries to save a buck and uses a stock valve spring with a high lift cam and high RPMs. The DFV was before the days of race engine leasing so sometimes teams would try to hot rod the DFV and fail as illustrated with the cylinder head in the video. What was used to visualize the explanation? A Slinky of course. At the 3:00 mark is the late Keith Duckworth (the WORTH in COSWORTH), the master himself.

 For more info on this beautiful Aston, visit www.one-77.com.

Aston Martin Reveals Spectacular One-77 Technical Showcase

Gaydon, Warwickshire - Tuesday 3 March - Aston Martin will present a One-77 technical showcase at the Geneva Auto Salon on 3 March 2009. Chassis no.1 will be on display as an expose throughout the show detailing the quintessence of Aston Martin engineering and design expertise.

The One-77 is Aston Martin's definitive sports car, one that epitomises everything Aston Martin from technology, the hand-craftsmanship of the hand rolled aluminium panels to the attention to detail. A culmination of all the marque's know-how, the One-77 delivers effortless beauty guaranteed to stir the senses with performance potential eclipsing any previous Aston Martin.

With the performance and durability phase of the One-77's intensive development programme soon to commence, the 79th Geneva Auto Salon provides the perfect stage on which to reveal the remarkable engineering, advanced technology and exotic materials that lie beneath the One-77's extraordinary exterior.

For Aston Martin's Chief Executive, Dr Ulrich Bez, revealing the One-77's secrets is a proud moment: "Right from the very beginning of the project the vision for One-77 was very simple: It had to combine high-technology with hand-built craftsmanship, and demonstrate the unique capabilities and passion of our designers, engineers and technical partners.

"Quite simply it had to be the ultimate expression of Aston Martin. As you can now see, we have achieved that goal in magnificent style."

Chris Porritt, One-77 Programme Manager continued: "We wanted to create something that wows you as much when you see what's under the skin as the exterior styling itself. We started by identifying the most technologically exciting front-engined, rear-wheel drive cars in the world: those from the DTM race series. We then applied the principles and technology that feature heavily in their design and translated it to a road car application."

Consequently the One-77's structural core is a lightweight and immensely rigid carbon fibre monocoque. Conceived and designed at Aston Martin's Gaydon HQ, the monocoque, or 'tub', has been built in partnership with Multimatic (MTC). As world leaders in carbon composite technology, advanced vehicle analysis and dynamic simulation, MTC brings unrivalled specialist capabilities to the exacting challenge of the One-77 programme.

Employing the classic formula of double wishbones at each corner, the One-77 features inboard suspension front and rear, with pushrods employed to transfer vertical suspension movements to the horizontally mounted spring/damper units. A practice taken directly from racing car design, the main advantages of inboard suspension are a reduction in unsprung weight and the ability to package the suspension components more effectively.

The dampers are fully adjustable and feature advanced Dynamic Suspension Spool Valve (DSSV) technology; a world-first for a road car application. These special valves are state-of-the-art even at the highest levels of motorsport, and use high-precision machined components to enable the shock-absorbing characteristics of the damper to be changed without having to remove them from the car, as is the norm.

Underlining the truly bespoke nature of the One-77, once delivered to its owner, the car's suspension characteristics will be precisely set-up by Aston Martin engineers to suit their exact requirements, from settings suitable for the ultimate long-distance GT, to a machine capable of conquering the Nurburgring Nordschleife.

While functionality and efficiency are paramount in the design and construction of the One-77', so too is aesthetic beauty. To this end every single component has been crafted from the finest materials with absolute attention to detail. From the mesmerising weave of the glossy carbon fibre tub and the abstract, sculptural beauty of the dry sump's oil reservoir, to the unerring precision of the billet machined aluminium suspension mounts, the One-77's rolling chassis is an automotive masterpiece.

Of course the irony is that the vast majority of these exquisite components will be hidden from view in the finished car, yet each and every piece is a work of art in its own right. It's this extraordinary workmanship and money-no-object commitment to quality that makes the One-77 unique.

Naturally, such a spectacular chassis demands - and gets - an equally exceptional drivetrain. It comes in the form of an immensely potent 7.3-litre, naturally aspirated V12 engine. Thanks to the adoption of a dry-sump oil system the engine is mounted 100mm lower than in any previous V12-engined Aston Martin road car, which helps keep the One-77's centre-of-gravity as low as possible. To further aid agility and endow the One-77 with progressive handling and stable, predictable on-limit behaviour, the engine is also mounted 257mm aft relative to the front wheel centreline. In so doing the front-midengined layout shared by all of Aston Martin's current road car range has been taken to a new level.

The One-77's magnificent power unit is an extreme evolution of the 6.0-litre V12 engines fitted to the DBS, DB9 and new V12 Vantage models. Like the collaboration with MTC for the build of the chassis, Aston Martin has chosen a world-leading partner with which to develop the motor: legendary engine builders, Cosworth. It has proved to be the perfect collaboration, as Chris Porritt explains.

"Our brief to the engine team was for them to take the 6.0-litre V12 as far as it could go,both in terms of output and weight reduction. The targets were a power output of no less than 700bhp with a 10 per cent reduction in engine mass. Incredibly, the Aston Martin and Cosworth engineers achieved a mass reduction of some 25 per cent, and although we've yet to complete the final engine calibration work, I'm confident we'll see in excess of 700bhp. It's an awesome accomplishment, but one that's typical of the One-77 project, for it has consistently brought out the very best in everyone involved."

Wearing Pirelli P Zero Corsa tyres (255/35 ZR20 front, 335/30 ZR20 rear) developed specifically for the One-77, all 700+bhp is transmitted to the road through the rear wheels via a new six-speed gearbox. Controlled via column-mounted paddles behind the steering wheel, this robotised sequential manual is a new generation of Aston Martin's familiar transmission. Though it is made specifically for the One-77 and features specially strengthened internals to cope with the tremendous power and torque, the lessons learned in its development will ultimately find their way into the company's series production models.

It's a mark of the inherent capabilities of Aston Martin's acclaimed lightweight Carbon Ceramic Matrix brake technology that it has been used as the basis for the One-77's braking system. The internals of the calipers have been re-engineered to transmit less heat from the brake pads into the brake fluid, while the discs themselves have been developed to ensure the maximum possible contact area between the face of the disc and the brake pads for improved stopping power. Due to the One-77's increased performance, special attention has also been paid to brake cooling, as the brakes have less time to cool between bursts of acceleration.

With a projected weight of 1,500kg the One-77 will occupy the very highest echelons of road car performance. Top speed is confidently predicted to be in excess of 200mph, with a 0-60mph time in approximately 3.5sec. Perhaps more importantly, thanks to the purity of a front-engined, rear-drive layout, the responsiveness and immense tractability of a naturally aspirated V12 and the low mass, high-rigidity properties of a carbon fibre chassis, the One-77 promises a driving experience of unrivalled intensity and excitement while representing the world's most desirable automotive art form.

Coming the first quarter of 2009 will be the first of a series of ECUs from Cosworth. The EC Pro ECUs are being manufactured by Pectel which is a division of Pi Research. Pi is a sister company of Cosworth and is part of the Race Power Group. Much like how Cosworth is at the forefront of engineering and motorsports, Pi and Pectel are at the forefront of engine control and data acquisition system for many different industries and motorsports including F1, WRC, Aerospace, Marine, Touring Cars, Military, etc.

While Cosworth is not necessarily known for electronics, we have been designing our own engine controls for many years now. The DFV F1 engines used a mechanical injection system of our own design. The move from mechanical injection to electronic fuel injection prompted the need for Cosworth to design their own engine controls. When this transition occurred in the early 1980s, Cosworth assembled an electronics section to engineer, manufacture, and service their own ECUs. Sometime in the early 2000s, Cosworth started to team up with Pi Research to develop ECUs for race engines. This partnership lasts even today with the Mazda MZR Formula Atlantic engines.

When the Cosworth Performance Parts division discovered a need for a high performance ECU, it was only natural for Cosworth to team up with Pectel once again. The first offering will be for the 2008 Subaru Impreza STi with the twin AVCS EJ257B engine. This ECU will only work on STis sold on the North American continent. Here's a list of features:

Cosworth by Pectel EC PRO ECU:
Designed for full OEM harness and system integration: Plug and Perform. Base calibration supplied to run a stock engine including all ancilliaries and external functions including air conditioning. 100% Ready to dyno tune for your engine specifications after installation. There is no need for replacement of OEM wiring harness or sensors and will will function in both air flow and speed density modes. Makes use of OEM dash and diff controller.

56Mhz processor: Higher performance timing accuracy and control
Ethernet comms: Fast data offload and high quality data viewing on PC
Internal logging memory pre configured: Logging essential channels at correct rates for performance analysis by your dealer
Internal logging for user: Additional logging for monitoring & development
Knock monitoring: OEM MIL lamp indication of Detonation levels (with user defined levels based on RPM and Boost)
Calibration select (e.g. Fuel save, Test, Race): Use of the OEM SI Drive switch for selection of 3 alternate calibrations (calibration selectable for boost, fueling, ignition, rev limit, ALS setting, VCAM target, Fly-By-Wire pedal mapping, and overrun fueling cut-off individually selectable for Intelligent, Sports, and Sports-Sharp).
Pectel ALS (Anti lag system): OEM switch used for ALS mode select
Standard Motorsport design: Machined Aluminum case and professional motorsport specification electronics.
External wideband supported: Compatible with most popular brands
Internal wideband supported:WBL kit: Requires Cosworth by Pectel NTK sensor, requires 3 extra populations and 2 pin relocating
Thermocouple support : TC Kit can be fitted for monitoring or control strategy e.g. exhaust over temp enrichment, auto ALS disable. Requires two blank pins on OEM harness populating.
Variable CAM: Fully programmable pre-configured full quad camshaft support
External Comms support: Optional Motorsport dash
Designed for off road use only: No OBDII monitoring

This ECU will be sold by select Cosworth dealers only on the North American continent. These same dealers will also be trained to handle tech support of the EC PRO. While the ECU will be user programmable (e.g. fuel, igntion, boost, config tables), full access is only given to these same authorized select Cosworth dealers. Target pricing should be under $3500.

Here is an ECU and  CDI box from the 1991 version of the DFS CART engine.

That's quite a few RPMs isn't it?

Here's a more recent Cosworth ECU that was used from 1999-2006 seasons of the Champ Car/CART Cosworth XFE engines.

In the 2007 Champ Car season, Cosworth switched over to the more modern Pectel SQ6M ECU to control the XFE engine. Similar technology is used in the Cosworth by Pi EC Pro ECU (sans mil spec connectors of course).

This is the Cosworth EC Pro ECU. It's coming soon! While you may believe that Cosworth is a "new kid on the block" with ECUs, we have in fact been creating, designing, and engineering ECUs far longer than the rest. You can bet that all of our and Pectel's motosports experience is right inside the EC Pro.

Somebody sent me a link to this video. This video is very obviously not a Cosworth production so it's not a web marketing sneak attack or anything. Anyhow, its great to see real world performance improvements of a product you had a hand in:

Recently there has been quite a bit of VQ35 work going on in the build shop here. The VQ35 has a lot of untapped potential from the factory. Simply bolting on a set of Cosworth CNC big valve cylinder heads, Cosworth camshafts (available end of summer), Cosworth Twin Plenum intake manifold, a set of headers, and a good remapping can increase horsepower from the factory 287bhp to 363bhp. That's an increase of 76bhp with just bolt on components!

Walking through the machine shop one day, I saw that Colin was balancing a factory VQ crankshaft for a special project. It turns out that the Cosworth piston, piston ring, rod, and bearing combination is approximately 110 grams lighter per cylinder. With this being the case, it was critical that the crankshaft gets rebalanced with the lighter component weights. Nearly 100 grams needed to be removed (48 grams front and 44 grams rear).  Any crankshaft that is not a flat plane design requires rebalancing with bob weights. If you do the math, that's 110g x 6 (6 cylinders of components) + 100g (crank) = 760g total weight savings.  That's 1.676 pounds or 26.81 oz. in weight reduction! It may not sound like a lot, but it is the weight reduction and the increased strength of the components that will allow an engine to last longer and spin to higher revolutions while doing so. The Cosworth rods and pistons are forged and the bearings are tri-metal so all of the Cosworth components are superior in strength. Every off the shelf Nissan VQ35DE short block built at Cosworth already has these same components


Bob weights are attached to simulate the weight of the components.


If a clutch and flywheel assembly is to be used, then it should also be balanced with the crank and indexed to the crankshaft. If your clutch and flywheel is already balanced, then it is not a major issue to balance the crank by itself. Most high performance or racing clutches are balanced from the factory.


Here the crank is almost balanced at 0.55 grams. We balance cranks to within 0.5 grams, but Colin is about to make the final adjustments. Precision is everything if you want excellent results.

During our extensive Subaru engine development program, the one thing we noticed is that the factory Subaru engine block's cylinder bore dimensions are very inconsistent right out of the box. This is fine with a factory cast piston because there is very minimal expansion in a cast piston. However, this can be a huge problem with forged pistons that are designed to expand when hot. If a forged piston is designed to have .003" of piston to cylinder wall clearance, what happens when the bore is oval by .002"? If you were to drop in a forged piston without honing the EJ257 cylinder block, the result is an eventual catastrophe.

First off, understand that the EJ257 cylinder block is more of a "case" than it is a block. Because it is virually hollow and its walls are quite thin, it is subject to severe distortion when head and block fasteners are torqued. Here are some tips for honing a Subaru engine block:

1. 1. Torque the case halves together with the fasteners you will assemble the engine with.



2. 2. Always bore and hone the cylinders with a torque plate and dowels in place. You should always use a head gasket (used ok) of the same make and model as your new gasket and also use the studs or bolts that you will be using in your final assembly. Steps one and two will allow the cylinders to be honed while "distorted" in its final assembled state.



3. 3. Always follow the piston manufacturer's recommendation for piston to cylinder wall clearance. If in doubt or if the engine will be used for severe duty, add .0005-.001" to the recommendation. It is generally safer to have more clearance than less with forged pistons.



4. 4. Always follow the piston ring suppliers recommendations for bore finish and crosshatch angle. Same with the piston ring end gaps.



5. 5. While a cylinder bore's perfection comes from the machinist's experience with your particular engine block, it is good practice to let the cylinder block cool before finish honing if there was a lot of material removed from the bore.

Follow these 5 simple tips and you should have a good running EJ257 if the engine is assembled correctly. If you haven't picked it up already, you should know that a "drop in" forged piston just will not last very long in a Subaru engine block without custom boring or honing from an experienced machinist.


Here is a factory EJ257 block straight out of Subaru's packaging with a custom designed Cosworth deck plate (available winter 2008) with the new Cosworth H-11 tool steel head studs.


Here is a measurement of the cylinder on axis with the crankshaft. You can see that it is .0011" from zero (the dial bore gauge was "zeroed" using the guage point on the piston).


Here is the thrust side of the cylinder bore measuring in at .0012" from zero. The cylinder bore is oval by .0023"! A "drop in" forged piston that called for a .003" piston to cylinder wall clearance definitely would not last very long in this cylinder block.

We are working on the new EJ257B from the 2008 Subaru Impreza STi and have one on the engine dyno at the moment. Some components we are planning on testing and developing are the dry sump oil system, CNC ported cylinder heads, valve train, camshafts, intake manifold, and a couple other goodies.

It is a long hard road to design components that work. This engine dyno installation took us nearly 200 hours to design, manufacture, install. The test engine is using a Garrett GT35R turbocharger, TiAL 44mm wastegate, and Cosworth/Pi ECU. Our engine dyno cells are complete with 18" thick walls, climate control (temp, humidity), barometric control, and are complete with many, many channels of data acquisition. I'll post a tour of a dyno cell in the near future. For now, the next time you purchase a Cosworth product, you can be confident that your Cosworth component has been tested thoroughly for reliability and horsepower.


2008 EJ257B dual AVCS custom dyno install with custom header.


Dry sump oil system in action. Also notice the huge intercooler in the background to the right.

The engineering department is hard at work finishing up the final prototype pieces of the Subaru EJ20/25 dry sump system. Many of our EJ25 engine customers are now winning in the various classes of Time Attacks and club racing events so we thought the next logical step would be a dry sump oil system. The EJ engine suffers tremendously from oil starvation due to high G turns and will pump out a significant amount of engine oil through the valve covers due to crankcase pressure (oil starvation + low oil level = disaster). While the Cosworth oil pan, oil control baffle, and high volume/high pressure oil pumps make great strides in oil control with a wet sump system, the absolute fastest cars at the track with sticky tires really should be using a dry sump oiling system for ultimate reliability.

A dry sump oil system not only eliminates oil starvation, but also produces a vacuum in the crankcase so that excessive crankcase pressure no longer becomes an issue. Also, there are small horsepower gains from vacuum being present in the crankcase since the laws of aerodynamics do not apply in a vacuum.

The Cosworth dry sump system is still in the prototype stage and will still go through several stages of testing. For this reason, there are no details regarding what the system will include or it's exact cost. Please wait until the end of summer before bombarding us with questions we have no answers for at the moment. I just wanted to share one of the more interesting things going on here in the building.


Here are the prototype parts fitted to an EJ25. The belt drive is designed to work with the factory dampener, but should also work with many aftermarket dampeners/pulleys with minimal hassle. The billet pump bracket is extremely strong and is designed to keep pump alignment perfect under any circumstance.


The pan will be machined from solid by CNC. This piece is still in the prototyping stage, but should be done soon. The best apart about product development is validation. I think I'll be offering my test driving services at the track!

The Cosworth NC Miata supercharger is now in the final stages of development. Soon we will be submitting a car to an EPA lab for CARB testing since our goal is to make this supercharger system 50 state legal. I got the chance to drive it around last Thursday and take some notes to refine the engine calibration. I was in boost just about the whole night and I can say that the supercharger system has given the Miata MX-5 a much needed boost in horsepower and torque. It feels like it has a nice broad, flat torque curve from about 2800-6500 rpm.

In its current configuration with a completely stock engine and exhaust, our car is currently making 210hp at the wheels which roughly translates in to 235-240bhp. The stock Miata made only 130hp at the wheels. With an increase of 70hp at the wheels, you can imagine how much quicker the car feels. That's a 53% increase in horsepower!

Please don't pick up the phone and call us just yet. The intercooled supercharger system is NOT available to the public yet. We are aiming for the end of summer as a release date. Calling us now would be a futile effort.



A clean OEM look was our goal from the very beginning. Some of the hoses here are not in their final routing positions as this is a first article installation.

Hello all. My name is Eric Hsu and I have been with Cosworth for almost two years now. I was hired to manage product development for the Performance Parts department. I work closely with the sales and engineering departments to ensure we supply the highest quality components for high end club racing and time attack vehicles.Our quest to supply the highest quality components and engine assemblies falls right in line with Cosworth's illustrious 50 year history of supplying the highest quality race engines and engineering consulting.

Check back regularly as I will be posting about random Cosworth related subjects. My posts will be mostly about product development, product testing, dyno sessions, component design, tech tips, etc. Whatever I post about, I hope you'll find it interesting. Thanks for reading!