Bonneville Salt Flats in Utah, USA, are used to high speed

visitors. In 1914 Teddy Tezlaff drove a Blitzen Benz at 141.73mph

to set an unofficial record and the Salt Flats achieved

international fame in the Thirties through the efforts of Salt

Lake City racer Ab Jenkins, who set a number of endurance

records in his Mormon Meteor. Tales of the firmness of the

surface attracted legendary land speed record breaker Sir

Malcolm Campbell who, on 3 September 1935, became the first

man to exceed 300mph with a speed of 301.129mph in his

Bluebird. Campbell was succeeded later that decade by fellow

Britons George Eyston and John Cobb and, in the mid-sixties,

American Craig Breedlove became the first man to break the

400, 500, and 600mph barriers there.

However, the Flats had never seen anything like JCB DIESELMAX

which, in August 2006, set and then broke a series of records to

become the first diesel-powered vehicle to achieve a stunning

350mph (563kph).

JCB DIESELMAX was the brainchild of JCB Chairman Sir Anthony

Bamford, born of his desire to showcase the extreme

performance of the JCB444 diesel engine, which normally

powers the company's backhoe loaders and Loadall telescopic

handlers. With a drag coefficient of only 0.174Cd, JCB

DIESELMAX is fitted with two JCB444 common rail diesel

injection engines, bored out to 5000cc and fitted with specially

modified twin compound Garrett turbochargers that use

lightweight housings, since weight is a crucial issue. Power

output is 2 x 750bhp @ 3800rpm and the engines deliver 1105

lb ft of torque at 2500rpm. Even with two six-speed manual

gearboxes, the car weighs only 2700kg including fuel, oil, ice

and water coolant and driver.

The driver was Andy Green, who set the World Land Speed

Record in 1997 when driving ThrustSSC, with which he became

BTN Turbo Limited, BTN House, Arundel Road, Uxbridge Trading Estate, Uxbridge, Middlesex UB8 2RP, England

Telephone:+44 (0)1895 466666 . www.btnturbo.com

the first and only man ever to drive at supersonic speeds when

he averaged 763.035 mph on the Black Rock Desert in Nevada.

Running soon after daybreak on 23rd August he recorded

365.779mph (588.664kph) on his first run and 335.695mph

(540.248kph) on his return, giving the average of 350.092mph

(563.418kph).

As he celebrated with his jubilant crew, Green said: “I am so

pleased that we have got the car to 350mph, which was always

our ultimate goal, and that was with a slow start to the second

run. There is so much more to come as the car is pulling like a

train and we still haven’t used sixth gear!

“Today’s record proves the potential we have always believed

JCB DIESELMAX to possess. This is another great result for a

wonderful team and a testament to British engineering. What

we have is basically a digger engine that has been made into the

most powerful diesel car engine in the world.”

"To have built the world's fastest diesel in such a short timescale

is a wonderful achievement for the JCB DIESELMAX team,” said

Dr Tim Leverton, Project Director.

“What is even more

impressive is to set three

records – 317.021mph,

328.767mph (526.027 kph)

and 350.092mph (563.418kph)

in only six days.”

VNT™ is a registered trademark of Honeywell International. VGT™ and Holset Command Valve™ are registered trademarks of Cummins Turbo Technologies

BTN MAG Rev4 M2.qxp 27/11/06 15:12 Page 1

Welcome to Revolution

Mark’s remarks

4Another year is nearly over and what a remarkable year it’s been for the turbocharged internal combustion engine,

as Audi wins Le Mans (and everything else) with a diesel powered car and a tractor company reaches 350mph with a

diesel engine!

I hope you’ll find this issue of Revolution as interesting and informative as previous copies. Our Sales and Marketing Director,

Mark Dickinson, has started a new column by looking back at the industry in a year that sees us celebrating the turbo’s

100th birthday; our technical people have given us an explanation of how modern turbochargers can vary throughput to

maximise efficiency and power; and you can see how a successful racing team is marketing an upgrade kit that takes an

Audi TT to 350 bhp.

It’s been another good year for BTN Turbo, too. Our initiatives, including turbo recognition from the VIN, the ‘new for old’

replacement policy on an increasing number of units and our ‘12 month no quibble’ warranty on commercial vehicle turbos

have enabled us to maintain our market leading position. For more information on our services, including fault finding, build

sheets and our complete catalogue, please go to www.btnturbo.com where you'll also find we've added a 'Spin Doctor' section.

By the time you read this Christmas will be nearly upon us. On behalf of everyone at BTN Turbo I’d like to wish you an

enjoyable festive season and a happy, prosperous New Year.

Rachel BirchEditor

In this edition you can see that the turbocharger has just

celebrated its 100th birthday. Yet it wasn’t until the sixties that it

was used on an American production car and it didn’t take off in

European passenger cars until the seventies. Now consider that

BTN Turbo was founded in 1974; that means we’ve been around

for about a third of the turbo’s lifetime and we were there at the

start of the revolution on this side of the Atlantic.

In 1974 petrol was 11.4p per litre and fuel consumption was only

just becoming an issue because that year there had been a fuel

crisis, which kick-started the drive for economy. Turbos were

used to boost power on already powerful vehicles. Diesel engines

were noisy lumps used mainly in trucks and agricultural vehicles.

And our business was 100% remanufacturing.

Today, nearly 50% of all cars sold are diesel powered, and most

of them use a turbo. Diesel engines are quiet and smooth, and

the turbocharger has become a sophisticated, essential part

of the powertrain in the drive for greater efficiency and

lower emissions.

BTN’s business has developed from the remanufacturing days to

the point where we have become the largest independent turbo

distributors in the world, with nearly £2.5 million invested in

new stock at our Uxbridge warehouse. We do still service, repair

and remanufacture units, but times are changing, and brand

new, OEM turbos now account for 80% of our business.

Two more awards for BTN Turbo

We don’t want to sound smug, but when we receive awards you’ll

excuse us for being proud!

At the recent Automechanika show in Frankfurt, Germany, we were awarded

the Garrett Performance of the Year Award for 2004 and BorgWarner’s Distributor

of the Year Award for 2005.

In our 32 years of trading we’ve won 22 such awards, which recognise the levels of service and expertise that have made BTN Turbo

the leading independent distributor of turbochargers in the world. It’s good news for us; good news for our customers; and just a

little more polishing for our cleaners!

How times have changed!There are two reasons for this. The first is that, frankly, some

units aren’t worth repairing. By the time we’ve stripped it,

obtained the parts, cleaned it, reassembled it and calibrated it,

the costs add up to more than buying a new one off the shelf.

That’s why we’ve rationalised the range of turbos that we

remanufacture.

The other reason is the complexity of variable turbine units, such

as Holset’s VGT™ and Garrett’s VNT™ models. They require such

sophisticated setting-up that any work other than light

servicing is beyond the capabilities of even the most skilled

technicians. That’s why we’ll always supply ‘new for old’ when

you need a variable turbine unit.

I can see that remanufacture will get even more difficult as

future technology, such as the electronic controls that we’re

beginning to see, comes on board. For our customers' benefit,

we’ll keep on top of the latest developments, but we won’t

compromise on quality, safety or economy. It probably means

the balance will shift even further towards new units and you

know you can rely on BTN Turbo to supply what you need, when

you need it.

The turbocharger has come a long way in 100 years.

We’ve come a long way in the last 32 years. Personally,

I’m looking forward to the developments and challenges

of the next decade or so!

Just three days after the Pakistan captain Inzamam-ul-Haq was charged with ball tampering during the fourth Test, he and the

rest of his team were due to entertain BTN and our guests by playing Middlesex in a one day test.

Unfortunately, torrential rain soaked the ground the night before the match. After a long discussion on the pitch, the outfield

was declared unsafe and the game was called off.

But rain did not stop play for the BTN Dealer Day. The lunch, which was attended by seven

of our top dealers and representatives from Garrett, Cummins (Holset) and BorgWarner,

went ahead with delicious Indian cuisine. During the meal Ed Goodwin, Garrett's Director of

Independent Aftermarket announced he had just become a grandfather for the first time.

As soon as lunch was over, everyone headed for the tenpin bowling alley near Heathrow.

The change of venue was quickly arranged following a suggestion from BTN Sales and

Marketing Director Mark Dickinson.

It may come as no surprise, therefore, that the winner of the bowling challenge was the very

same Mark Dickinson! As Trevor Cass, Garrett Product Support Engineer said afterwards,

“Despite the cricket being cancelled, the day was great - it is all about the people you are with

and they were a great bunch as usual.”

BTN’s Dealer Day plays on... despite the rain

Industry comment from Mark Dickinson,

Sales & Marketing Director of BTN Turbo

BTN MAG Rev4 M2.qxp 27/11/06 15:12 Page 3

Ask little boys what they want to be when they grow up and many

will say “fireman” or “racing driver”. Milton Keynes-based turbo

dealer Mark Hosken has achieved both – and he’s still only 35!

Scorching up the track

“It all started with motorcycles,” he told us, “though, being a

safety-conscious person, it wasn’t possible to enjoy the speed on

the roads, so I turned to the race track where I could explore the

full potential of some magnificent machines.“

Mark then turned to four wheels. “ I raced the superb Formula

Honda Single Seater made by Jedi for two successful seasons,

reaching second place in the scholarship class in both years. In

2002, whilst testing cars for a TV programme, I came across the

awesome Ariel Atom 2 and, by 2004, we had successfully turned

this fast road car into a race winning machine.”

Audi TT bosted to 350bhp

His next project was the car you see on these pages: an Audi TT

that displays all of Mark’s expertise in race car preparation. The

4WD Audi has the chassis Mark was looking for, and an engine

that has proved itself as the prototype for a turbo upgrade kit that

pushes the output to 350bhp!

Since preparing the Audi, Mark has achieved several podium

finishes including an outright first at Silverstone.

Full-time in automotive and motorsport

This year, Mark resigned from the Fire Service to concentrate

full-time on his career in motorsport and turbo distribution.

The company name – Backdraft Motorsport – pays homage to

his firefighting background and covers four principal activities.

As Mark puts it, “We are a motorsport company. We specialise in

developing and producing complete turbo upgrade kits. We sell

OE and upgrade turbos to the motor trade and retail. We build

and prepare race vehicles and we prepare and race our own race

car.” With the support of BTN Turbo, Backdraft

Motorsport offers a next-

day service for all

replacement turbos.

The first turbo

upgrade kit is

for the

Volkswagen,

Audi and Seat 1.8T

engine, as developed

Top quality components fit the engine bay perfectly

Race-proven turbo upgrade kit is a winner

Tristan tears up

the track!

The winner of our free draw in Issue No 2 of

Revolution took to the track recently,

spending a fabulous day at Silverstone.

Tristan Seal, a Director of independent

motor factor APD Cotswold Ltd in

Gloucester, spent the day with his wife,

Leanne, driving a variety of vehicles both on

the track and off-road.

It was an action-packed day but some early

rain meant that they had to be careful,

particularly with the Formula cars.

Thankfully, it cleared up for the afternoon

and Tristan went on to win two events.

He told Revolution, “The instructors pushed

us beyond what we both thought we were

capable of and the amount of grip some of

these cars have is just phenomenal. We

started the day spinning doughnuts in a

Lotus Seven and I went on to win the Lotus

Extreme challenge - three laps around the

main circuit, which was great! The one event

that neither of us was really looking forward

to was the pit stop challenge where, as a

team, we had to change the wheels and

driver on a Formula 2000 car. This turned

out to be a real scream and we pulled

together as a team and won it: in fact, we

set a time that was almost eight seconds

faster than any team that our instructors

had ever seen before."

Tristan recommends that anyone interested

in performance cars should save up and

treat themselves to the Silverstone Track and

Rally Experience, saying, “The day was

fantastic - the only drawback was that it

was all over too soon.”

Mark Hosken’s 350bhp Audi TT in action

for the Audi TT race car. It adds an average 120bhp over the

standard output and is supplied complete with a Garrett

GT2860RS turbo, coupled to a cast manifold for durability and

reliable performance. The kit includes beautifully crafted, TIG

welded and polished stainless steel charge, inlet and down

pipes, together with colour co-ordinated silicone hoses with

Hi Grip hose clips.

Remarkably, the kit costs less than £3,000 (installation and

remapping not included) and can be installed in a couple of

days, either at Backdraft Motorsport, a fitting centre or by any

workshop with a good working knowledge of turbocharging.

Mark is in the process of establishing a network of approved

fitting centres, so if you’re interested please give him a call on

01908 676140.

Safety first

It might be down to Mark’s firefighting background, but he is

unique in that his after sales service includes safety precautions

for his customers. “Fitting a turbo upgrade can turn a car into a bit

of a beast”, he says. “If you’re not prepared for it, you can go wrong

on the first bend. I like to spend time with my customers, showing

them how to handle the car in a way that is fun and safe."

BTN MAG Rev4 M2.qxp 27/11/06 15:12 Page 5

Cummins Turbo Technologies are the world leaders in the design and manufacture of commercial

turbochargers. Its range of Holset® turbochargers can be found breathing life into an ever larger number of

the world’s diesel engines.

The ‘Holset’ success story began in 1948, in Huddersfield, when W C Holmes became interested in

manufacturing the flexible couplings designed by Louis Croset. In 1952, with a name created from the HOL

of Holmes and the SET of Croset, Holset Engineering Company Limited was established with Paul Croset,

OBE as Managing Director. In 1973 the company became part of Cummins Inc, a $9.9 billion corporation

of complementary business units that design, manufacture, distribute and service engines and related

technologies, including fuel systems, controls, air handling, filtration, emission solutions and electrical

power generation systems. In May 2006, as part of Cummins’ new branding strategy, Holset Engineering

Co Ltd was renamed Cummins Turbo Technologies Ltd. However, the company will continue to brand its

products with the internationally renowned ‘Holset’ name.

From the start, the company focused solely on medium to heavy-duty diesel engine technology, and

continues to do so to this day. Its key strategies are product development and partnership: Cummins Turbo

Technologies has an impressive track record of being first to market with many air handling technologies

and works closely with its customers to integrate those technologies into their engine developments.

Technology for today: Holset VGT®

One of Cummins Turbo Technologies’ key innovations is its Holset VGT® technology. The patented sliding

vanes vary the area of the nozzle and thus control the flow through the turbine to give good transient

response; better fuel economy; increased useful engine operating speed range;

enhanced compression brake capability; reduced engine swept volume and

package size for a given rating; and higher pressure ratio compressors.

(See Spin Doctor in this issue.)

Cast titanium compressors

In 1997, Cummins Turbo Technologies was the first turbocharger

producer to offer cast titanium compressor technology, which provides

enhanced levels of mechanical strength without compromising the

sophisticated blade geometry.

Cummins Turbo Technologiesworld leaders in turbochargers for commercial vehicles.

The semi-electricage is upon us

The current trend is towards the hybrid car -

that is, a vehicle that combines a petrol or

diesel engine with an electric motor,

charged by a generator that is active during

deceleration and the otherwise unused

kinetic energy generated by braking. At

start-up and low speeds, the electric motor

powers the car. The carbon fuelled engine

kicks in under acceleration and, at mid-

range speeds, both motors work together to

maximise efficiency.

Virtually every mass car maker is working

on the technology. Toyota, Honda and Lexus

already have hybrid models on the market;

Volkswagen and Audi are co-operating

with Porsche to develop a range of petrol-

electric hybrid engines; Ford has launched

the Escape hybrid SUV in America; and

DaimlerChrysler, Nissan, Peugeot, BMW,

Land Rover and General Motors among

others have all shown hybrid concept cars.

General Motors, DaimlerChrysler and the

BMW Group have formed a cooperative

effort called the Global Hybrid Cooperation,

which is actively developing the next

generation hybrid powertrain system.

Hybrid cars inFormula 1?

The president of the FIA has announced that

he would like to make a form of hybrid

engine mandatory in Formula 1 from 2010.

The technology would be similar in principle

to current hybrids but is not aimed at making

F1 cars cruise around circuits more sedately

and fuel-efficiently. It will require the energy

generated by the car’s braking system to be

stored to provide brief bursts of ‘free’ extra

power. On the basis of current technological

knowledge, the system would provide about

60 extra horsepower for about nine seconds

in each lap, which could help eradicate F1’s

much-criticised lack of overtaking.

It is argued that teams are spending

hundreds of millions of pounds on ‘sterile’

development of extra power from current

conventional engines, when F1 should be

showing a technological lead to make future

road cars more environmentally friendly.

Heavy duty diesel turbocompounding

Cummins Turbo Technologies pioneered the introduction of turbocompounding

on production diesel engines, in partnership with Scania, as long ago as 1993.

The concept was tried in the 1940s on aircraft engines, but the promise of low

fuel consumption for transport aircraft was overtaken by the development of

gas turbine and turboprop engines.

The principle introduces a power turbine downstream of the turbocharger, which

generates more work by re-using the exhaust gases that have passed through

the turbo. This work is fed back into the engine crankshaft through a

sophisticated transmission. The main benefit is increased overall thermal

efficiency, providing more power and using less fuel.

Holset Command Valve™

Pulse Width Modulated (PWM) wastegate technology is well established on small,

passenger car petrol engines. However, for accurate control of the air-fuel ratio,

external control of gas flow through precise regulation of the wastegate is essential.

Cummins Turbo Technologies and its partners faced a number of challenges in

developing their PWM hardware known as Holset Command Valve™ for the medium

and heavy diesel market. It had to maintain durability over a service life of up to

1,000,000 miles and withstand sustained temperatures well above those experienced

in light vehicle turbocharger environments. In addition, customer input showed that

ease of installation and reliability as well as cost were prime considerations.

After an extensive test programme, the chosen solution was a metal bodied

valve mounted directly into a boss on the compressor cover by a single large

thread, sealed by three O-rings.

Electronic integration

Cummins Turbo Technologies was one of the first turbocharger companies to

offer electronic inputs from the turbocharger to the engine ECU to ensure the

extraction of maximum product performance without jeopardising durability or

reliability. Electronic sensing of turbocharger speed was originally developed for

the Holset VGT™ and further development has enabled the company to offer

this capability in any Holset turbocharger using induction probe technology.

Further inputs, including compressor inlet air temperature measurement and

pre-turbine pressure measurement, can also be offered.

The company will

continue to brand

its products with

the internationally

renowned ‘Holset’

name

Advanced production facilities for commercial vehicle turbochargers Turbocompounding introduces a power turbine behind the main turbo

BTN MAG Rev4 M2.qxp 27/11/06 15:12 Page 7

Garry Jones

Next up is Garry Jones, who has overseen Commercial Operations for BTN for 15 years.

He’s a real family man who likes nothing better than playing in the park with his children;

he sees BTN as ‘family’ too and loves the fact that it is a close-knit, friendly team.

He recalls an enquiry he received last year for a turbo for a coach. “What year is it?” he

asked. “2005 – you should know that!” came the reply. “No, what year is the bus?” he

queried, to be told, “I don’t know, but it’s a 57 seater!”

Lisa Holah and Mark McKervey

Those of you who contact BTN regularly may already have spoken to Customer Services

Executive Lisa, who joined the team in August of this year. She is very familiar with the

automotive environment, having spent most of her life in the company of mechanics,

including a spell running a garage in Portugal with her ex-husband. A keen dancer and

reader, she also likes the friendly atmosphere at BTN and enjoys dealing with customers

and sorting out their queries.

Mark is another Customer Services Executive, who arrived in October. He knew what to

expect, as his cousin already works for BTN. Mark’s interests include supporting Liverpool

FC and reading, especially military books; he is an Army Cadet Instructor in his spare

time and was recently promoted to Sergeant.

In this issue of Revolution, we’d like to introduce you to two men called Garry, and

two of our newest members of staff.

Garry Podmore

Our first Garry is Operations Director Garry Podmore, often known simply as

‘Poddy’. He is responsible for all operations, infrastructure and production at

Uxbridge – a wide-ranging brief that reflects his experience in the turbo industry

and his eleven years at BTN.

He’s known Sales and Marketing Director Mark Dickinson for many years, having

worked with him at Lucas Turbocentre where he was Factory Manager in the early

nineties. With his extensive background in remanufacturing and production, Garry

was the obvious person to approach when BTN needed a Production Manager to

work with Ken Tilsed (the ‘T’ of BTN).

Garry’s attitude of ‘Always do your best, with no half measures’ saw him rise to the

board and he still gets a lot of satisfaction from helping the Sales team to resolve

issues and leave customers with a smile.

A former footballer (two broken legs, fortunately not at the same time, told him

when it was time to retire), he now plays golf with a passion and a handicap of 22.

He is particularly keen to let everyone know about his hole in one!

The first

'PROPER' motorcar

It’s official – the automobile is 120 years

old. Controversy has raged over who

fitted the first engine to a set of wheels,

but it was in 1886 that Karl Benz applied

for a patent for his motorised vehicle.

With the German Reich Patent No.

37435a, granted in November of the

same year, his Patent Motor Car, as this

three-wheeled vehicle has since been

known, received official recognition as

the world’s first automobile.

It was the individualised technology that

secured the Benz Patent Motor Car this

status. Unlike other inventors, Benz did

not merely install an internal combustion

engine into an existing coach chassis,

thereby making it capable of autonomous

motion (Greek ‘auto’, Latin ‘mobil’). His

design extended to the entire car, because

he appreciated that a vehicle powered by

an internal combustion engine was

subject to engineering principles quite

different from those applying to a horse-

drawn carriage.

Benz created innovative technology with

classic engineering methods: a small

horizontal, single-cylinder four-stroke

engine running on gasoline, electric

ignition, carburettor, water-cooled

radiator, steering and a tubular frame.

So next time the question “Who invented

the motor car?” comes up in a pub quiz,

remember to quote Benz’s patent number!

Happy 100th birthday to

the turbochargerA century ago, just twenty years after the invention of the automobile

(see left), Swiss engineer Alfred Buchi was studying steam turbines when

inspiration struck: why not spin the wheel with exhaust from an internal

combustion engine and use the recovered energy to force-feed the intake

side? It was a brilliant concept, since roughly a third of the energy in fuel

is normally squandered out the tailpipe.

The first applications were for aeroplanes, and the results were promising. In an

early experiment conducted after World War I, General Electric engineer Sanford

Moss fitted a turbo to a Liberty V-12 aircraft engine and conducted high-altitude

testing. Without the turbo, the V-12's 354 hp at sea level dropped to 230 hp at

altitude. Boosted by a ten-inch-diameter turbo, the blown Liberty cranked out

377 hp at 14,000 feet.

GE's timing was late for the First World War

but perfect for the next global conflict. Vastly

improved turbochargers gave Allied bombers

and fighters major range and altitude

advantages throughout World War II. More

than 300,000 turbocharged aero engines were

manufactured by GE and Ford.

Diesel ship and locomotive applications began in the 1920s. Turbo-diesels are an ideal

marriage, because there's no throttle to stall the air delivered by the compressor. Turbo-

chargers hit the road in diesel trucks beginning in Europe in 1949. A year later, Cummins

added turbos designed by Buchi - then in his seventies - to American-made diesels.

Cummins also sponsored turbocharging's racing debut. In 1952, a turbo-diesel roadster

driven by Fred Agabashian qualified on the Indy 500 pole and led for 100 miles before

dropping out when tyre debris clogged the turbo.

Oldsmobile offered the world's first turbocharged production automobile, the 1962

F-85 Jetfire V-8. The F-85 arrived just ahead of Chevrolet's Corvair Monza Spyder (later

Corsa), but the Corvair demonstrated more staying power. Nearly 50,000 turbo Corvairs

were sold during five model years versus fewer than 10,000 Jetfires delivered in its two-

year run.

The Turbo Offy first ran at Indy in 1966 and started winning two years later. At its peak

in 1973, it generated 1000+ hp for qualifying. Concurrently, Porsche was leading the

Can Am series with its 1100hp 917/30. Turbos dominated Le Mans beginning in 1976

and one year later invaded Formula 1.

Inevitably, success on the track triggered the modern era of turbocharged production

models. BMW launched a 2002 Turbo for Europe in 1973. Porsche presented the first

911 Turbo at the 1974 Paris Motor Show. Buick joined the throng in 1977, Mercedes-

Benz (diesel) and Saab in 1978, followed by Pontiac in 1980 and Volvo in 1981.

During the last quarter-century, the list of car manufacturers offering turbocharged

models is longer than the tally of those who don't. From backyard tuners to luxury

limousine manufacturers, they've all relied on Buchi's turbocharger, the most efficient

horsepower helper ever invented.Liberty V-12 aero engine with ten-inch-diemeter turbo

Garry Podmore

Garry Jones

Lisa Holah

Mark McKervey

Putting a face to the name....

BTN MAG Rev4 M2.qxp 27/11/06 15:12 Page 9

Producing a turbocharger for an engine that only runs at one speed and load would be easy. However, vehicle

engines are constantly changing speed and, when a turbocharger is fitted, it has to do its best to deliver the

best possible response under ever-varying conditions.

In the last issue of Revolution we looked at wastegates: valves that allow some of the exhaust to flow around

the turbine instead of through it. This limits the turbine power at high speed when more exhaust energy is

available than is needed to drive the compressor and allows the use of a smaller turbine, sized to generate boost

at low engine speed (i.e. when the wastegate is closed) without overboosting at high speed.

This system offers smooth and simple control, but still does not deliver the perfect solution. The exhaust energy

bypassed around the turbine is wasted (hence the name wastegate). At high speed a turbine with a larger

nozzle could use all the exhaust flow and generate power with less exhaust backpressure.

Turbocharger manufacturers realised that the ideal system would have an adjustable turbine nozzle that acted

like a small turbine for fast response at low speeds and a large turbine for maximum power and efficiency at

high speeds. It should also be possible to open it fully to minimise backpressure when boost is not needed. This

led to the development of turbochargers with movable vanes, the two most popular being Holset’s Variable

Geometry Turbocharger, or VGT™, and Garrett’s Variable Nozzle Turbine, or VNT™.

In both of these technologies, the vanes rotate by sliding or pivoting to change the area of the nozzle, or throat,

that the exhaust gases pass through. The smaller the nozzle, the faster the gas velocity, providing more turbine

power and more boost. The vanes then gradually open as exhaust flow increases, to minimise exhaust back

pressure, control boost pressure, improve fuel economy and increase horsepower. In effect, it does act as a small

turbo as low rpm and a large turbo at high rpm.

The throat section modulation can be controlled directly by the compressor pressure through the use of a pressure

In the next issue

of Revolution

Oil - it's vital to

keep your turbo

turning

Varying throughput for better response and economy

Peugeot unveils Garrett-

boosted diesel Le Mans

contender

Following the phenomenal success of Audi’s diesel-powered

R8 and R10 sports cars – the R8 won the Le Mans 24 Hour

race five times between 2000 and 2005 and the R10

triumphed in every race it entered this year - Peugeot has

revealed a challenger. The Peugeot 908 that will compete at

Le Mans and in the ‘Le Mans Series’ in 2007 will be powered

by a V12 HDi diesel engine with a capacity of 5.5 litres - the

maximum capacity permitted by the regulations.

The choice of a 12 cylinder engine helps keep the cylinder

bore diameter very close to that of a production series engine.

In doing so, Peugeot can call on its extensive knowledge of

diesel combustion and also ensure the engine has a

reasonable piston stroke. The V12 architecture, well known for

its good balance, also reduces engine vibrations to a

minimum and the 100° V angle makes it possible to lower the

height of the engine's centre of gravity without affecting the

engine's torsional rigidity.

The two exhaust systems are kept as short as possible. On

each side a six-into-one exhaust manifold is connected to a

Garrett turbocharger, then to a very compact diesel

particulate filter, before ending in a side exhaust pipe located

in front of the rear wheel.

Peugeot expects power output to exceed 700 bhp and torque

in excess of 885 lb ft. This should make the 2007 season a

nailbiter between the Germans and the French but, whoever

wins, Garrett will be sharing the podium!

actuator, or by the engine management system using a

pneumatic actuator that harnesses air pressure from the

vehicle’s braking system.

VGT™ and VNT™ turbos therefore provide improved transient

response (i.e. reduced ‘turbo lag’); better fuel economy;

increased useful engine operating speed range and torque,

improving drivability and response; reduced emissions; and

they allow manufacturers to build engines with a smaller

capacity and package size for a given rating.

The drawback is that these turbochargers are complex bits of

machinery that require immense knowledge and facilities to

build and maintain. For that reason, they are beyond the

remanufacture capabilities of even the most advanced turbo

specialist except for light servicing, and the manufacturers do

not release spare parts. That is why BTN Turbo, as an official

aftermarket distributor for Garrett and Holset, now only

supplies brand new VGT™ and VNT™ turbochargers (on a new

or exchange basis) instead of remanufactured units.

This is not only the most cost-effective solution: it means that

our customers have peace of mind, knowing that the

replacement turbo is identical to the original – it’s exactly the

same turbo that you would receive from the OEM.

SPIN DOCTORSPIN DOCTOR

VGT pneumatic actuator

Compressor housing

Speed sensor

Turbine wheel

VGT actuating yoke

VGT push rod

VGT nozzle ring

VGT shroud plateTurbine housing

Speed sensor connector

BTN MAG Rev4 M2.qxp 27/11/06 15:12 Page 11