Exige V6 air intake - pinched from another site.

Anyone read this?

<LINK_TEXT text=“https://www.thelotusforums.com/forums/t … ke-system/”>Exige V6 Air Intake System - Engine & Ancillaries/Gearbox - The Lotus Forums - Official Lotus Community Partner</LINK_TEXT>

Excerpt below :

where do I start, we’ll back in January I realised my CupR intake system was pretty poor at filtration, I also noticed the internal surface of the carbon piping was also starting to look a little worse for wear. The filtration in particular worried me as I remember reading back in the day how bad those iconic mushrooms actually where at filtration.

I returned back to OEM as a starting position in order to get a benchmark of what my standard power output actually was before starting with my own design. Lets just say it was somewhat frustrating returning the car back to standard and re-installing all this stuff!

On returning back to OEM the car did feel a little sedate, throttle response a bit dull and for sure a massive reduction in noise and supercharger howl!

I decided to go to Litchfield Motors for the dyno run, they have in my opinion one of the best dyno machines in the UK, their reputation is first class, they have no bias as they were not selling something to me, nor competing with any other tuner as they don’t specialise in Lotus. In essence good guys, knowledgeable, do things right, and an honest run.

Standard power from factory is claimed to be 345bhp and 295lb ft of torque.

Let’s just say on first look the 326bhp recording was somewhat disappointing! However, after speaking to a number of other owners it became apparent this result was quite common for a standard Exige V6.

With a standard benchmark now recorded, I started to think about the new intake design, the primary objective being to develop something which was a simple ‘bolt on’ solution, improved throttle response, didn’t need an ECU re-map, and brought back that wonderful howl of the supercharger. In a perfect world a slight improvement in power to get anywhere closer to the claimed 345bhp would be a blessing.

To say designing the intake has been easy would be a lie, I’ve machined two different MAF flanges, tested three different pipes, and tried three different air filters. In the region of eighteen possible variations!

The first design I found the pipe too small, then too big, then just right! The MAF flange needed a tweak to ensure the right protrusion as close to standard OEM as possible to ensure the MAF could work without hinderance. MAF flange and pipe size (material thickness changes) actually made a frustrating difference to protrusion but eventually got there!

In terms of the actual air intake I decided to go with ITG. I first tried an enclosed unit but even though their big in total unit 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.

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.

I decided to go back to basics with an open air filter, the position would be right on top of the side intake duct and being soo far out of reach from the engine bay shouldn’t be too much affected by heat soak. Again back to testing filters and the first filter even though rated to 400bhp had the noise but not a 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 bite the bullet and commissioned a custom design which met my dimension needs and rated to up to 470bhp.

Out for testing… https://youtu.be/zNJXvqxR2ns

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! I came back home very very ‘chuffed’ but knowing that sometimes these things are just in ones head I decided to call Litchfields again and get booked in for a dyno run :slight_smile:

Fast forward to today…

The car ran perfectly, same dyno, same fuel (99 Tesco Octane), standard ECU, standard exhaust, but with the new intake design.

Now before we get to the run results I have to say, the results are going to cause a number of questions, but the runs where done on the same machine, same operator, and if anything at slightly higher air temperatures.

YES those figures are REAL – 391bhp and 327lb ft

Compared to my first standard run the difference in numbers is somewhat questionable, so we ran three further runs getting to an average power reading of 386bhp and 323lb ft.

We had three of the Litchfield senior techs review the data, the car setup, which gear used, anything which could distort the figures and we came back to the same answer … the numbers are real and correct. AFRs also reviewed and everything showing nice and safe even at the top end of revs.

Now when you remove the thought of my original standard run, and instead see the improvement being from 345bhp to 386bhp, everything feels more sensible.

Regardless I’m a very happy boy today, all the hard work, effort, and cost (£600 in dyno runs alone!) has been worth it for today’s run!

A BIG THANKS to everyone whose been involved in this project and supported me, especially when I went through that ‘sod it I can’t be arsed phase’

To conclude, I wont be packaging this upgrade as ‘the’ 380bhp kit, but for sure it ticks all the boxes in which I sought out this project – Simple, No ECU Re-Map needed, Improvement to throttle response, Improvement to sound… oh and I guess the big surprise a nice Improvement to power and delivery :slight_smile:

I have read it and been watching Imran closely (Friend of mine)

I wonder if its something as simple as long term fuel trims have been tweaked. Would be great to see Imran on here!

It seems like the ‘before’ graph is the most suspect one, something like a small boost leak or a configuration issue on the dyno.

Even if the ‘before’ graph showed the ~350bhp that was expected, it’s still a bloody good increase to make the ~390 afterwards.

I dunno how significant it is in dyno terms, but the ‘before’ run was revved out to 7215rpm and ‘after’ run only 6630rpm. I just googled it and v6 rev limit is apparently 7k? Does that suggest a calibration issue on the first run?

Rev limit is 7200rpm on the V6S


I’d love some supercharger noise and RELIABLE extra power which is enduring and readily serviceable.

But not yet convinced by independent stats and proven over time. In my heart, I really want this to be very good indeed, but I don’t want to risk my car when driving under load e.g. on a track day.
All I want is a proven supplier of extra power and great (even better) sound…but do I need to go Exige 430 to get it?