Lotus Twincam air filter

[Dobbo]

What can the panel recommend for air filters for a Twincam with 2 x 40s.

I've sorted the silencer and now all the noise is from the induction system.

Will air filters make a substantial difference to noise levels?

Any for sale and /or a bonnet with hole cut in (bent scratched dented etc ie cheap) to play with and decide if its the way I want to go.

 

Dobbo

 

 

Edited by - dobbo on 8 Oct 2001 21:56:38

[R2D2]

It all depends on the type of front wings you have. The Twin Cam engine has the inlet tracts in exactly the same axial position as a crossflow but they are significantly longer. (You can get away with a crossflow bonnet without too much trouble.)

 

If you have clamshell wings the maximum filter depth will be 56mm to allow the bonnet to fit between the wing and the air filter, Even then you will have to modify the bonnet slightly by removing the return that fits against the chassis for the length of the filters.

 

The standard crossflow K & N s are just a little too deep but they do manufacture one which is 56mm. (I have the part no. at home if you get stuck)

 

I would also fit a set of 19mm bells into the 40's. This is the shortest standard bell that will fit and give the minimum recommended clearance to the filter plate (25mm).

 

The original Lotus 7 Twin Cam SS set up used a 25mm deep paper filter without bells to give wing to filter clearance but I have always believed the cab is better with a bell.

 

If you have cycle wings there is no problem and you can fit crossflow K&Ns or any similar filters.

 

I have tried Pipercross and ITG socks but prefer the K&N.

 

Edited by - chris flavell on 9 Oct 2001 12:51:08

[Dobbo]

Thanks Chris thats very usefull,I had not even considered that the wings could affect things, It's a S2 seven with clamshell wings.

The bonnet only has a small cutout for an air scoop fitted at the side. I don't want to cut or modify anything till I am certain its the way to go.

[R2D2]

I have a photograph of an original 7 SS I can scan if it would be of help. I can't think that an original bonnet will fit without serious mods. Isn't the air scoop onthe wrong side of the bonnet? I thought that a pre-crossflow engine had the carb on the nearside of the engine bay and the TC has the carbs on the offside.

 

Edited by - chris flavell on 9 Oct 2001 15:11:17

[deanteam]

Our S3 Lotus with Twin Cam, not an SS I'm afraid, has to run without airfilter because of the space. The bonnet is enclosed with a bulge around the carbs. Space is a problem as Chris explains, but do you want to fit the air filter for protection of the engine or to reduce noise? Air filters don't reduce the noise very much at all.

[Dobbo]

I had the chassis re skinned and ordered a plain bonnet, no holes and added the air scoop myself. Iv'e run the car with the Twincam and no air filters for 10yrs with no probs so I,m really just after trying to get it as quiet as I can without cutting holes etc. then to find its no better.