Letting the Lotus Exige V6 S3 Breath!
The OEM air box of the Lotus Exige V6 S3 is surprisingly clunky, its a mix of pipe work and boxing which when removed you wonder why the hell did Lotus need to shoe horn soo much complexity into the engine bay.
You then start to contemplate the weight and the barriers all the pipe work and boxing actually creates in delivering a nice flow of air into the supercharger.
So I decided to make it better and based the design around four core objectives:
- Simplify: Remove the complexity of the OEM air box. Develop a simple solution that removes weight and removes all the boxing which prevents air to circulating and aiding cooling in the already cramped engine bay.
- Bolt On: A solution which is an easy bolt on which can be done by most owners with simple tools without hours of labour or the need for an ECU remap.
- Noise! The enclosed design of the OEM air box just doesn't allow you to hear the supercharger howl. This needed to change!
- Throttle Response: Simplified design would mean a straighter and higher rate of air flow into the charger. The aim being primarily to sharpen the throttle response vs chase big power numbers.
To say designing the intake has been easy would be a lie. Challenges with getting the right MAF flange, intake pipe, and filter have resulted in testing numerous variations before finding the right mix.
In the end machining two different MAF flanges, tested three different pipes, and tried three different air filters. In the region of eighteen possible variations!
Getting the right protrusion of the MAF was a nightmare to get right to ensure the design matched as close to OEM as possible. This was important to ensure the MAF could work without hinderance and allow the ECU to re-learn without an error code and need for a re-map.
MAF flange and pipe size (material thickness changes) actually made a frustrating difference to protrusion. Off the shelf MAF flanges just didn't work, in the end I had to machine my own.
In terms of the actual air intake I decided to go with ITG as a class leader supplying F1 teams, BTCC drivers, Manufacturers Championships and the Japanese Super GT Champion.
I first tried an enclosed unit but even though they're big in total size the actual internal filter was often quite small. A few tests and I just didn’t feel happy, the throttle response wasn’t great and no real improvement to sound.
I then went for a larger enclosed unit to get a bigger internal filter, but this meant pushing the unit back into the engine bay and closer to the heat of the engine. To try and get the most out of the design I also added a ‘ram air’ input, but all in all no noticeable difference in testing.
Going back to basics with an open air filter, positioned right on top of the side intake duct and being soo far out of reach from the engine bay the hope was to reduce the risk of heat soak.
Again back to testing filters and the first filter even though rated to 400bhp had the noise but no noticeable difference in throttle response. Unfortunately just going one size up didn’t really work with overall dimensions of intake pipe and room to play with so I bite the bullet and commissioned a custom design which met my dimensions and rated to up to 470bhp.
Out for testing…
The car felt great, for the first time in all the variations of testing, an immediate feeling of improvement to throttle response, power came on faster, the howl was loud and the car just felt alive!
Measurement of AFRs in third and fourth gear across the rev range showed a healthy operating range between 11-12.
Knowing the risk of heat soak could be a problem on track, initial testing was done at Castle Combe circuit on a very hot day!
Followed by an evening at Donington Park to fully test and ensure the intake didn't breach any drive by noise limits at full on hot lap mode!
Looking at offline data shows the car consistently performed lap on lap with no perceived degradation of power leading from heat soak, as a standard practise I do open the rear hatch when back in the pits to help with cool down post each session.
To conclude the intake continues to impress, meeting its original objectives, and proving to keep its performance levels consistent even on very hot track days lap after lap.
So what's in the box... A little video walking through what you get in the box when purchasing the ALIAS23 air intake kit with a few tips on installation.