V6 Airbox restrictor?

[JCERB]

Morning All,

Just joined here after 6 months of owning such a great car! I have just replaced the old air filter for the TRD and noticed a secondary filter inside the lid? What is that all about? Never seen this before.

Many Thanks.

[Bibs]

Hi and welcome Joe. 

I can't see a 2nd filter in the parts diagram? 

[JCERB]

Hi Bibs, cheers!

 

Indeed nothing there on the diagram. It's plastic riveted into part no.2 so you can't see the actual plastic from the inside, just a meshed filter that effectively sits on top of the replacement filter. It looks factory fitted my car is a 2015. I wondered if it was for noise restrictions...It must stop a lot of air flow.

 

Cheers

[Bibs]

I just called one of the engineers at Lotus for you and they recommended it stay in place. It may had a role in the air flow to the MAF which sits right above it and they ECU's are quite particular about the MAF readings, you'll probably end up with a light on the dash if it's gone.

[JCERB]

Thank you very much for that, most helpful and really good of you. That would make sense for MAF readings. I wonder if it was just on the later V6's. I just thought it was odd when I saw it. I guess a Komo-Tec filter would sort that. I wonder if anyone has one of these on a standard exhaust, as I imagine it must sound awesome. Probably still not quite as good as a CSL air airbox.

[chumaxa]

Aftermarket exhaust does no make much more noise, I have a carbon one, just release a lot of bhp with the right map .. Standard box is so restrictive indeed ... 

[Bravo73]

3 hours ago, JCERB said:

Morning All,

Just joined here after 6 months of owning such a great car! I have just replaced the old air filter for the TRD and noticed a secondary filter inside the lid? What is that all about? Never seen this before.

Many Thanks.

It’s a carbon filter, required for the US market. 

I removed it from my OEM Evora S airbox (same as the V6S) and had no ill effects. It is downstream from the main, paper filter. 

 

[JCERB]

Hi Jonny,

So do they all the V6 Evoras/Exiges have it, or is it a left over US part they used maybe? Did it improve sound/response when removed? How did you remove it?

Thanks a lot.

[Bravo73]

I don’t know if all Evoras have it. It probably only came in after the Evora was ‘federalized’ so some of the earlier NAs might not have it. However, I suspect that all V6Ss would have it. 

It’s very easy to remove. Just carefully drill out the plastic rivers/fixings. Et voila! Out it comes.

Did it make a difference? Theoretically, yes it must (because the airflow should be slightly less restricted). Could I feel or hear any difference? Hell no! 

 

If you’re happy modifying your airbox, there is a vacuum actuated flap (in the lower portion of the airbox) which can also be safety removed.

 

[Kristof Thys]

It also acts as an air straightener decreasing turbulent air over the MAF. On a car with a real time afr gauge you can clearly see the afr's jumping around at idle without such air straightener. 

Edited June 21, 2018 by Kristof Thys

[JCERB]

Interesting stuff indeed. I just saw it and thought WTF! Maybe I'll leave it for now, but the flap sounds a good idea. Why would they have done that? It would be nice if the car had a throatier roar.

Thanks a lot guys for all your help here, it's really appreciated.

[Hangar 111]

23 minutes ago, Kristof Thys said:

It also acts as an air straightener decreasing turbulent air over the MAF. On a car with a real time afr gauge you can clearly see the afr's jumping around at idle without such air straightener. 

This.  It is a diffuser for the MAF, which is quite close to it.

The flap is deleted on later cars - if you disable or remove it, you will need to retain the solenoid actuator (else MIL), and ensure you don't introduce any vacuum air leaks.

Dave

[JCERB]

I see, so the flap must be located between parts 3 - 7 from the diagram posted by Bibs? Any noticeable benefits to doing this mod? Later cars being the 350? An onboard clip of your Komo-Tec filter would be good to hear, it looks a quality bit of kit.

Cheers

[Bravo73]

Yes, the flap is in the tube at the base of part 3. It is now removed at the factory with a pair of tin snips! (I found that secateurs work just as well). 

It is held open by vacuum pressure. On long straights at WOT, the vacuum pressure might decrease sufficiently that the flap closes, hence restricting airflow to just the smaller tube (part 6). 

It is definitely removed on the 400. I don’t know about the 350, I’m afraid (but it is easy enough to find out). 

[Hangar 111]

59 minutes ago, JCERB said:

I see, so the flap must be located between parts 3 - 7 from the diagram posted by Bibs? Any noticeable benefits to doing this mod? Later cars being the 350? An onboard clip of your Komo-Tec filter would be good to hear, it looks a quality bit of kit.

Cheers

Yes where 7 joins on to 3, you can see the vacuum actuator which flips the flap.  Taking the whole thing out of the car isn't too difficult providing the bolts holding part 3 to the bracket haven't seized.

We are edging nearer to having our Exige demo car finished, at which point can do some video of the SC whine

Dave

[JCERB]

Good old tin snips! I see so quite restrictive, potentially.

Maybe when it comes out I may go for the komo-tec filter. Is the installation fairly straight forward? Can the ECU reflash be sent? It would be nice to put it back to standard easily too.

[jackettc]

Looking at that diagram, isn't that an awful design for airflow??

Other than the overpriced Komo-Tec cold air intake (£1,500 with remap!), does anyone know of an alternative to get rid of, or modify this thing?

And have Lotus changed this on any of the later cars like the 410, 430's, etc ?

 

 

[Bravo73]

Yep to the airflow - but I guess that it made sense on the RAV4 (where it comes from originally). 

There are some aftermarket alternatives:

BOE (USA)

ES Motorsports (UK)

Lir Racing (France)

Komotec/H111 (Germany)

They all work on the same principle of a larger paper or foam cone filter.

 

All OEM Lotus V6 cars still have the same RAV4 intake. 

[jackettc]

Many thanks, contacted BOE for more information

[Bravo73]

I see that you’re in the UK, Chris. Once you factor in delivery & taxes etc, the BOE option will turn out to be very expensive (especially considering that the filters are actually manufactured in Coventry!)

You will be better off (pricewise) with one of the other options.