Airbox Derestrict

[chris.100]

I have a question about derestricting of the Z20LET airbox with regards to the small cone piece inside the box.

This type of cone is called a Bellmouth Intake, and is used on gas turbine engines, usually helicopters, as the shape of the intake actually speeds up the flow of air.

It is also used on high performance engines.

This is the only pic I could find really

http://www.velocity-of-sound.com/velocity_of_sound/images/cobravs2.jpg

wondering if anyone can shed more light on this subject, as reming it could possible reduce the efficiency of the intake

[dannysport18]

just take out and stick it the bin mate :)

[GeordieBandit]

dont worry about scientific theories here - its a tried n tested method within the Vauxhall community and a mod that is proven to work over years of experience.....

upto u of course - ur car - ur choice

if u think it'll reduce the efficiency then do a comparison before and after and let us all know the results

[chris.100]

unfortunately i got rid of my coupe, looking at another one now though, just got to convince our lass.

just got me thinking cos i did a gas turbine course in november last yr and the instructor, a very experienced gas turbine engineer and owner of big engined jag's, said that is why they are installed in the first place.

found another pic

http://www.classicjaguar.com/jctl701.jpg

[chris.100]

come on guys. someone else must have an opinion on this topic

[buckle]

I ripped it out, with the turbo sucking air in, wouldn't it be able to suck in more without a pipe getting in the way?

[marcus_valver]

I done the mod (on coupe turbo) but didnt add the veccy c pipe right away, it wasnt until i added the veccy c pipe did i notice any improvment but its certainly worth doing

[dannysport18]

unfortunately i got rid of my coupe, looking at another one now though, just got to convince our lass.

just got me thinking cos i did a gas turbine course in november last yr and the instructor, a very experienced gas turbine engineer and owner of big engined jag's, said that is why they are installed in the first place.

found another pic

http://www.classicjaguar.com/jctl701.jpg

yes but that will be covered by a big air filter/airbox mate

[chris.100]

I ripped it out, with the turbo sucking air in, wouldn't it be able to suck in more without a pipe getting in the way?

A little turbo found in the engine bay of a car will not 'suck' anywhere near the amount of air as a jet engine geezer. Its the principle of gas flow through a pipe here, not just removing pipes, just by removing some of the pipework doesnt mean more air will flow.

i cant quote the science for definate but this type of intake increases the flow of a fluid

[dirtyrider]

hi
i am thinking about getting mine done with the veccy c pipe simply because larger pipe or less of, might allow more air into the turbo quicker. i dont see the relevance of posting pics of throttle bodies as there is nothing too restrictive such as pipework and box restricting them. as already stated if you wish to do the mod then great, people on here give advice as best they can trying to improve performance and its only through trial and error this can be done in most cases. nothing is gospel but you read the reviews and comments and make up your own mind. trying to relate jet engines too a 2.0 litre turbo is a bit of a stretch and i do realise in fundamental basics such as the wheel they are similar.
also when this modification is done there is a bit more noise so it may be possible it was also there to keep noise down. i hope you find the answer you are looking for but most of the guys are car modifiers and not designers.
good luck geezer!!

[chris.100]

I appreciate your reply mate but I didnt bring this topic up to annoy or argue with anyone. When I had my coupe I did this mod myself (including removal of said pipe). Regards to the pipework, I agree that the new intake pipe will increase the airflow, but it is the small cone shaped pipe in the airbox i am talking about.
The design of the intake system will have a sound reducing property, no doubt, I am just wondering whether there is any advantage removing this pipe.

As for the pic of throttle bodies, I am simply pointing out that a high perfomance system uses these "bellmouth" intake tubes.

As for the comparison of a Jet engine to a turbo, they are basically one and the same, a compressor driven by a turbine, its gas theory which is the issue here.

[dazerc]

I've heard before that leaving the bottom pipe in the air box gives you more torque.
The only way you to see if it makes a difference to the flow of the air is to test it somehow. i'm not an expert but there must be a way to test which way the air flows the best.

[the polisher]

Also take a look at an air filter that hasnt had the air box mod. You'll see that half of it is very dirty whereas the other half is clean. When the air filter is new this isnt a problem, but after a couple of thousand miles surley the mucky part of the filter will restrict airflow? By removing the pipe the whole filter is used and thereby giving longer lasting perfromance.

[chris.100]

I've heard before that leaving the bottom pipe in the air box gives you more torque.
The only way you to see if it makes a difference to the flow of the air is to test it somehow. i'm not an expert but there must be a way to test which way the air flows the best.


the pipe im talking about is the exit from the airbox fella. Im sure all airboxes will have this type of pipe in