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Established in 2002 our reputation has been built on the innovative design and production of high performance exhaust systems. As a supplier to various race teams including bac mono and cga race engineering, our systems withstand the most extreme conditions whilst providing the highest performance gains.

The Alunox customer base has grown due to its specialist use exotic materials such as Inconel, Titanium and various grades of stainless steel such as 321. This combination of ground breaking flow designs with the highest standards of welding and fabrication has made Alunox the first choice for race teams and enthusiasts alike.

Alunox has become an established supplier of uprated aftermarket systems to Aston Martin, Noble, TVR and many others, including Lotus.

Alunox have a promotion on the Uprated Esprit Charge Cooler , it active on the LEF (March 2014)
At present the charge cooler for a one off is in the region of £825.00 + VAT and the front rad to be costed out,

Again Look on the Lotus forums for an active group buy for an offer price. If your interested sign up to the forum which is free or mail Leon with your details and you will be added to the list.

Special Promotion price of £550 + VAT for Group Buy of 10, currently running on forum
Alunox have a promotion on the giugiaro-stevens-esprit-turbo-321-stainless-steel-manifold-group-buy, it active on the LEF (June 2016)
£900 + VAT for the Stevens Car
£1250 + VAT for the Giugiaro Car


Lotus Esprit Turbo Products

Stainless Steel 321 Manifold

Alunox are now able to provide manifolds for both cars and due to advances in CNC technology they share components. The 321 Stainless Steel manifolds are upgrades for both Giugiaro and Peters Stevens 4 cylinder Esprit’s. For those of you who haven’t seen this upgrade before, a recap on the history of the company and the product:

Alunox are an established engineering company that supply the motorsport industry with tailor made high end exhaust systems, made of exotic materials such as Inconel, titanium and 321 Stainless Steel etc. They also supply BAC cars with a full light weight for their current production car the Mono.

Alunox took on the job of redesigning the original cast manifold for the Esprit due to its high failure rate and short life cycle. They are direct replacements for the existing cast items.

The manifolds are made from 321 Stainless Steel, precision TIG welded in dedicated jigs giving a fracture proof construction. The flanges are now CNC machined cut out of Stainless Steel to give an accurate fit, the collector uses burns double slip joints to allow movement during the heat cycle whilst being protected against shock loading by the pivoting brace mounted at the back of the head.

Giugiaro Full System

The wastegate is a Turbosmart compgate 40 mounted on V-Bands which is included in the manifold kit

Stevens manifold

The downpipes are all equal length mandrel bent tubes which increase the pulse tuning effect greatly over the standard non equal length log cast configuration of the original unit. In addition to this flow is also maximized due to the smooth internal surfaces arranged to fit within the space available unlike the rough flaking internal bores of the original. The collector is now a CNC machined single piece for maximum durability and strength. It also offers an option for the Stevens Cars to run an external wastegate.

The manifold has been proven to withstand all the temperatures and conditions produced by the Esprit due to the 321 Stainless steel properties. Even at normal driving speeds the exhaust gas temperatures are typically 750 to 850 °C and greater during track use. The manifold is lighter than the original cast unit weighing only 6 Kg.  All these attributes produce a durable high quality product with proven gains in both power, torque and turbo lag reduction.

It has been dyno tested as seen in the video below on a highly modified Esprit running at 424 BHP and 409 lb ft torque. Further gains have been made since the video was made.

Further in-depth technical info on this can be found on Dave Changes thread  

It has also been track tested and driven hard without fail. Look for feedback on TheLotusForums.com about performance gains.

The kit also includes all gaskets, stainless steel nuts and brace. The turbo flange can be changed to accommodate different turbos, as can the collector be made to order. These adjustments are at extra cost and can be discussed with Leon at Alunox.

The prices are different for each manifold kit due to the extra work / component parts of the G car set-up. Every manifold comes with one year’s warranty.

The kit now uses the proven stainless steel K nut design for the manifold head studs as standard. This is an improvement over the Lotus locking tab washers which are no longer required.

The brace is mounted from the rear of the cam carriers with the heatshield and uses a fully adjustable turnbuckle for easy fitting.

Steven’s Car

The normal one off price is £1150 + VAT.

The kit includes
1 manifold
4 Head flange gaskets
1 Turbo flange gaskets
1 Brace with rear mounting bracket plate
12 m8 stud k nuts
4 Turbo flange nuts

Giugiaro Car

The normal one off price is £1500 + VAT.

The kit includes
1 manifold
1 External Wastegate – Turbo Smart Hypergate 40
1 return pipe (Manifold to rear system)
4 Head flange gaskets
1 Turbo flange gaskets
1 Brace with rear mounting bracket plate
12 m8 stud k nuts
4 Turbo flange nuts

Uprated Charge Cooler

The charge cooler was introduced to the Esprit for the SE model in 1989, mechanical changes over the Giugiaro 910S (HC) turbo 2.2-litre were comparatively confined, yet horsepower grew by 14 per cent and torque by 17 per cent. With the standard Lotus charge Cooler, the engine is capable of holding a transient 280bhp for periods of up to 30 seconds.

So by holding the temperature of the charge to as close to the ambient as possible, will result in a more dense fuel air charge. This will increase the volumetric efficiency creating more power and torque.  So we come on to the new uprated charge cooler from Alunox.

Description: http://www.lotusespritworld.com/images/adverts/Alunox/ChargeCooler_01.jpg
The core volume has been increased by 3 times. Now we have a greater cooling effect on the air and have a bigger bank of air to supply the plenum chamber.

The bigger the better and the Alunox Cooler is about as big as we can get into the available space, it’s mounted on two rubber mounting bolts with new brackets. The unit is has a curved inlet and outlet design to aid flow.

Installation is very easy with all the hose connections being in the same position as the original unit.
Larger diameter hose connections for the water feed is optional and can be specified when ordering.

Description: http://www.lotusespritworld.com/images/adverts/Alunox/ChargeCooler_02.jpg

Driving experience
We can only comment from the driving experience at the moment. Also this was only tested with the standard pump and radiator. You can still feel better torque on boost which doesn’t drop as fast at as the revs climb.

After driving hard, the charge cooler feels cool to the touch when putting your hand on the top surface.

The unit works well with the other modifications and enhances the Alunox manifold further.

Alunox are also looking to produce a high quality aluminium front radiator to match the thermal dynamics   of the charge cooler as part of a kit. This will be updated here.

At present the charge cooler for a one off is in the region of £825.00 + VAT and the front rad to be costed out,

Again Look on the Lotus forums for an active group buy for an offer price. If your interested sign up to the forum which is free or mail Leon with your details and you will be added to the list.

Stainless Steel sports exhaust with cat by pass.

This section completes the exhaust from the turbo back. It has been designed for balance and flow as well as offering a number of selectable characteristics to suit. 

The system is constructed of high quality stainless steel with a flexible coupling to eliminate vibration and resonance. The downpipe section is removable mounted on a pair of V band clamps unique to Alunox which allow for a quick interchange with a catalytic converter if required.

The size of the rear silencers can be chosen when ordering to set the noise level. The system is also available in 3” diameter tube for high powered cars.

And finally the tail pipe style is also optional.

Fitting is straight forward using the rubber mounts as per the standard system. Ask about options when ordering.
The one off price for this system is £625 + VAT

As before Look on the Lotus forums for an active group buy for an offer price. If your interested sign up to the forum which is free or mail Leon with your details and you will be added to the list.

Alunox  High Flow 3’ Stainless Steel Motorsport rear system

Alunox have developed two 3 ‘ rear systems to provide extra flow for high powered cars. Both constructed from high quality 304 stainless steel and fabricated in dedicated jigs. They use flexible couplings to eliminate vibration and resonance. Both systems will maximise the gains of the Alunox manifold.

Side Exit

Description: E:\Lotus\Rear 3 Inch Side Exit\IMG_6246.JPG
The silencers are larger due to the 3’ bore size in order to maintain track legal noise limits. They are designed to motorsport standards packed with high temperature silicone glass material. All tubes are mandrel bent providing smooth internal services and so maximising flow. Optional tail pipes styles are available and can be chosen when ordering. The system fits to the standard mounts of the Esprit.
One off Prices
2.5 ‘ System      - £550 + VAT
3’ System Price - £700 + VAT

Alunox  High Flow 3’ Stainless Steel Motorsport Centre Exit Rear System

Description: E:\Lotus\Rear 3 Inch centre exit System\IMG_6156.JPG
Again the silencers are larger due to the 3’ tube size. The silencers are designed to  motorsport standards packed high temperature silicone glass material. All tubes are mandrel bent providing smooth internal services and so maximising flow.
The system fits to the standard mounts of the Esprit. The system has been designed to maximise flow giving a power increase whilst improving throttle response. Again track legal
One off Price

Price £870 + VAT

Upgraded Alloy motorsport  radiator set for Esprit Turbo and V8 by Alunox

The standard set of radiators for the Esprit is dated in design and inefficient compared to modern aluminium cores. These original cores were replaced about 6 years ago and already showing a high degree of fatigue.

On close inspection it can be seen that the metal frame and cores are degraded pretty badly.

In this state the cooling capacity of the core has been reduced and potentially could fail allowing  temperatures to rise outside of the operating boundaries and lead to overheating.

The new aluminium set has been designed in line with modern standards and state of the art tube and fin configuration to deliver more efficient cooling for all systems on the Esprit. The radiators are an all alloy construction of motorsport grade, using fully welded and vacuum braised techniques. With the Esprit being mid engined the cooling systems have a lot of work to do to maintain Engine, Oil, Charge Cooler temperatures. 

A lot of us modify our cars for increased performance and don’t consider the extra demand on the cooling system. Modified cars require an uprated cooling system to help dissipate the extra heat generated and so allow the ECU optimise power output at stable engine temperatures.

Upgraded Main Core

The Main core has been upgraded to a modern design and increased in size. Alunox estimate that the core design change alone will give 35% more efficiency, but in addition to the core depth has been increased to 68mm from 50mm. To allow space for this increase the core has been set further back into the tray using a stepped design in the frame and end cap.

 This resulted in new stainless steel mounting brackets at the rear of the tray bolting to the existing fixings on the front of the chassis.
The new frame is constructed out of stainless steel and has rubberised mounts to reduce any sudden impacts and so aiding longevity. It also contains mounting brackets for modern fan units.

The fan system has upgraded to pull more air through the triple stack. The old fans have been replaced with curved blade high efficient units.

Upgraded Condenser Core

The new Condenser core is a radical change from the old pipe and copper fin design which gives far superior gas cooling for the refrigerant. It’s compliant with the new and old gases. All pipe connecters have been maintained to allow direct replacement. It also has rubberised mounts to allow it to fit in front of the main radiator and maintain its structural gaps.

Upgraded Charge Cooler Core

This new core has again been upgraded in both core design and size, maximising the space available. This gives the Esprit a performance gain by providing more cooling capacity to the charge cooler.  All new pipe work and brackets are supplied in the kit taking the existing diameter of the pipe work up to 19mm as oppose to the exiting 16mm. Pipe reducers allow connection to the existing runs, giving the option change later.

To maximise the performance gain of this you should also consider replacing the mechanic pump with an electric one and running the larger diameter pipes to the rear of the car.

This radiator complements the uprated Alunox Charge Cooler and will maintain the intake charge temperature as close to ambient as possible.

Upgraded Oil Cooler Cores

The new oil coolers have been redesigned taking the depth up to 80mm and now have their own cooling fans. The Esprit normally struggles to bring down its oil temp after standing in traffic, with the new oil cooler this will be improved.

The Complete set for the ultimate cooling system

All fittings remain the same, just slight modifications required to the oil cooler ducting to allow for larger core.

The frame is made of stainless steel with mounts for fan units, which combined with the Aluminium cores gives a very durable product that will way out last the original.

The set fits both the 4 cylinder model and V8. A new pair of charge coolers for the V8 is on the drawing board at the moment which could then be fed from the charge cooler Radiator in this set.

All the cores have been pressure tested as part of quality control. The new set also gives a weight saving over the original being 10kg lighter.

At this stage the set is a prototype, the price is governed by order volume on two accounts, the first being the core supplier who has to set-up for these bespoke sizes and second, Alunox has to tool up for their production run. Alunox are offering a 1 year workmanship warrantee on the set.

Alunox want to sell this as a full set and the price will reflect that, however I think the power of a group buy will give this a kick start for the production run.

The kit will contain:
1 off main rad with stainless steel frame
1 off Air conditioning condenser rad
1 off Charge Cooler rad
2 off Oil Cooler with pipe work
2 off Stainless Steel mounted brackets

Before you dismiss this when was the last time you had your radiators checked or even visually inspected the copper cores yourself? A coolant leak could cause further damage in the engine department if not detected early enough.

Whether your spending time on the track, use your vehicle in a warm climate or simply want to reduce those high temperatures when caught in traffic, this has to be a worthwhile purchase.

The standard Lotus set currently cost
Main Rad                                   £560
Condenser/Charge cooler         £325
Oil Cooler each                         £160
Total £1205 + VAT


After talking with Leon at Alunox we are looking at £1200 + VAT for the full kit without fans for a Group Buy of 20 or more. If you are interested in this product look on the Lotus forums as below


You can sign up to the forum which is free or mail Leon with your details and you will be added to the list.

Track Day Run
with Alunox performance products

I took the Esprit to Castle Combe this year to test all the Alunox components under track conditions. I’ve put together this video to help demonstrate the performance increases and reliability of the upgraded parts from Alunox.

The weather did give us a mixture of conditions to contend with, drying out as the sessions went on. I’ve shot it full HD1080p so you can adjust your playback setting if your broadband will support it.

The Alunox full system passed noise testing at 96 dBA, the limit at the Castle Combe circuit is 100dBA.

I’ve trained a small camera on the manifold shown in my last track session 9 minutes and 25 seconds into this video. I’m not sure about how the camera has translated the colour of the manifold as its glowing, but you get the idea

You can see the manifold cooling as I easy off the gas, demonstrating the extra induction cooling effect from the upgraded charge cooler.

The upgraded radiator set maintained engine temperature throughout the sessions. The upgraded charge cooler kept induction temperatures down and as a result I found no drop of performance throughout the sessions.

The overall driving experience is greatly enhanced with a turbo lag reduction and faster spool up giving a bigger punch in power delivery and more torque. What was also noticeable was the accuracy in throttle response giving me better control of over steer when exiting the chicanes.

Contact Leon on 01978 851100. e-mail  leon@alunox.co.uk
Or  visit website www.alunox.co.uk    

If you try this, feel free to e-mail us with your Verdict at admin@lotusespritworld.com


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