Air Filter Box to Hood Cutout Alignment

[pickles]

I know this is going to be a source of contention and debate, and has probably been debated many times, but here goes...

 

On both my previous 360 and my current 620 ... the alignment of the airbox/filter intake does not match the hood cutout.

 

On My 360 I replaced the whole airbox with a K&N cylinder filter, at the same time I replaced the Cat with a straight through connector ... It must have added at least 100HP ... obviously I jest! It did not, but it sounded like it did; the intake was throaty, and exhaust sounded like a whaling banshee! 

 

So now I come my 620 ... it too has a similar mis-alignment :-

 

Now I could spend time correcting and adjusting the airbox to match the hood opening, so here's the question(s) ...

 

• is it worth it?
• Is there some other configuration I should be looking at?

 

Feel free to beat me up on a subject that probably has already been ... beaten to death! 

 

Cheers

Pickles

 

[CBuff]

I have the same issue in my 420r. It likely doesn’t affect performance. But sends my ocd into overdrive.  Interested to hear people’s thoughts / solutions to this 

[Croc]

This subject has not been addressed and is remarkably common although most owners ignore it.  

 

So your somewhat stock 620 under bonnet configuration will look like this:

 

 

The cold air intake is the silver looking pipe that heads down and curves to the left to a black box then the rubber grommet that sits between the intake and the inside of the bonnet.

 

To rule out the bleeding obvious by those unfamiliar with the 620 engine - it has a supercharger.  The traditional upgrade path for regular Caterham Duratec engine owners of Caterham roller barrel throttle bodies is not a viable option.

 

Not a lot of room to work with either - and the photo is an SV.

 

Knowing that, lets see what you can suggest for Pickles.     

[pickles]

OK don't laugh, this is version 0.1(beta) 

 

Got rid of existing piece of rubber on the air-box, which was really not doing much. I went to Home Depot and got 1in. x 6ft Rubber Self-Seal Pipe Wrap.

Grabbed a few cable-ties, and this what I got.

 

Is it perfect, not yet! But is a better than previously? I would argue yes.

 

It does make putting the hood back on a little more difficult but not by much.

 

I think for version 0.2(beta) I will enlarge the 3 screw holes in the bottom of the air box where it attaches to the car, install some rubber grommets. May also play with some extra rubber washes to change the height/angle the box sites out for a better fit. (Plus, I have another 5ft of rubber tube to play with )

 

Pickles

Edited December 3, 2025 by pickles

[Croc]

I think that works well for a version 1 edition.  I suspect it will give a better cold air seal too.  Probably no extra hp though!

[pickles]

10 hours ago, Croc said:

I think that works well for a version 1 edition.  I suspect it will give a better cold air seal too.  Probably no extra hp though!

What are you saying!! I figure at least 0.25 HP extra