Designing Airbox

[Spiky 37]

ok, i need to quiet down my ITB's, so want to create a airbox i can bolt on for tracks that are more strict.

 

my question is, can do i make it equal infront of each trumpet? (basically the same as my current filter) then have a large intake on the one side

 

how much infront of the trumpet would i need to give, to get best air flow?

 

my next question is what filter to put on the end?

 

here are some pics to show what i currently have and the idea i want

 

what i currently have

 

 

 

what i'm thinking about making

 

Edited February 24, 2010 by Spiky

[swordfish210 20]

Trumpet spacing should be about 15mm, same as an airfilter. You need to work out how much air is being sucked in to the engine (use a syncrometer) then find a diameter for the end of the airbox that won't restrict the flow too much.

[Cameron 16]

I don't know if this is right, but with 45mm throttle bodies you should need a minimum airbox inlet diameter of 90mm.

 

That's based on the throttle area x 4.

Edited February 24, 2010 by Cameron

[Rippthrough 98]

I don't know if this is right, but with 45mm throttle bodies you should need a minimum airbox inlet diameter of 90mm.

 

That's based on the throttle area x 4.

 

Nah, they're not all breathing at the same time....something around 60-70mm would be fine.

Edited February 24, 2010 by Rippthrough

[Cameron 16]

Cool, I'll be using that info for mine then.

 

I'm yet to find some solid information on airbox volume, half what I've read says one thing and the other half says something completely different, but that's what you get for relying on the internet for information - misinformation.

Edited February 24, 2010 by Cameron

[John_B 11]

I'll be interested to see what you do, I want to do the same myself....

 

 

What about the Pipercross airbox? It is a hell of a price though.

 

Pipercross 600

[Spiky 37]

thats exactly what i need,

 

i dred to think of the price,

 

the lotus one i have a picture of is £465 which is a damm site more than i want to pay,

 

i'd rath go back to std inlet and pocket £1500 than spend another 500 on the intake, it's just not worth it.

[Spiky 37]

£212

 

http://cgi.ebay.co.uk/PIPERCROSS-C6100LH-P...=item51902eed74

[peakrevs 0]

ok, i need to quiet down my ITB's, so want to create a airbox i can bolt on for tracks that are more strict.

 

my question is, can do i make it equal infront of each trumpet? (basically the same as my current filter) then have a large intake on the one side

 

how much infront of the trumpet would i need to give, to get best air flow?

 

my next question is what filter to put on the end?

 

here are some pics to show what i currently have and the idea i want

 

what i currently have

 

 

 

what i'm thinking about making

 

 

 

 

 

The one in the picture looks very straightforward to fabricate particularly if you used 1mm thick steel sheet. Polished aluminium would look better but depends if you have TIG welding available.

 

The steel option would cost no more than a tenner for material and a bit of your time (which is free) for folding and MIG welding. Apart from the cost saving there's a great amount of satisfaction in making something.

 

This trailer for David Gardiner's tuition DVD is inspirational and shows what can be done with just normal hand tools that we have around us.

 

[Spiky 37]

i am going to attempt to make one like that in alloy, i have a local welder who i think is up to the job, well he makes bikes, so i'm sure this will be fine.

 

will pop up and have a chat to him

 

wil post pics on my progress

[Spiky 37]

also that guy, is seriously talented

[peakrevs 0]

i am going to attempt to make one like that in alloy, i have a local welder who i think is up to the job, well he makes bikes, so i'm sure this will be fine.

 

will pop up and have a chat to him

 

wil post pics on my progress

 

 

Great news; look forward to seeing your pictures.

 

If you are going for aluminium, I'd use 1.5mm grade 1050A or NS3. It is easy to work and easy to weld.

[Spiky 37]

really? 1.5mm would 1mm be a little flimsy then?

 

** just to add, genuiely not sure the answer, as i'm not an expert in this area **

[peakrevs 0]

really? 1.5mm would 1mm be a little flimsy then?

 

** just to add, genuiely not sure the answer, as i'm not an expert in this area **

 

1mm aluminium is very thin to weld but ask your friend what he would recommend as he's the guy who's going to do the welding. As I said, I'd go for the thicker material which is not only easier to weld but the finished job will be much more robust as well.

[Spiky 37]

sounds like a better plan then

 

thanks for the input.

 

glady put up pic's, only so my haters can have another moan at me ....pmsl

 

it's all trial and error, but it's fun trying

[peakrevs 0]

sounds like a better plan then

 

thanks for the input.

 

glady put up pic's, only so my haters can have another moan at me ....pmsl

 

it's all trial and error, but it's fun trying

 

 

You are absolutely right. There is nothing so satifying than having a go and eventually succeeding. One of the challenges I set myself once I was 60 was to learn to gas weld aluminium. I never thought I would be able to master it but in the end I did and it was so satisfying. I have also taught myself metal shaping and used the trials special as a project to improve my skills. I'll never reach David's level but it's good to have a target!

 

A couple of pictures of the front wings made from, you've guessed it, 1.5mm ally just to show what a geriatric can do.

[Spiky 37]

WOW pretty impressive that

[Cameron 16]

PSSSSST.. Have you thought about resonance? If you make your airbox out of thin sheet ally then it'll probably resonate louder than your throttle bodies were! You'd have to either make it out of thicker material or have some sort of strengthening ribs inside.

 

That's something I've been thinking about for mine, and I reckon it's probably going to be best to make it out of GRP. That way it's easy to shape, and you can use a core material to add strength and thickness without much extra weight.

[Spiky 37]

trial and error really, i'm going to try the alloy route and see what happens

[Cameron 16]

Fair enough, worst case is you can use it as a mould.

[Spiky 37]

exactly, maybe get someone like X-Sport to make it from GRP or carbon fibre, depending on price

[Spiky 37]

just asked someone about your concerns

 

I suspect you will struggle to get much resonance out of such a flimsy structure even if you were trying TBH, but it would be easily stopped with a couple of squares of dynamat on the outside of the box if you did find it happening, no big deal at all.

[Spiky 37]

nice link here

 

http://www.auto-teknix.co.uk/Airbox.html

[Cameron 16]

It's the fact that it's flimsy that causes all the problems, because the unsupported sides will vibrate in time with the pressure pulses. Play a bass guitar next to a snare drum and you'll see what I mean.

 

Actually our FS car has an aluminium airbox and that resonates almost as loud as the exhaust. If you look at the box when you blip the throttle you can see the sides suck in!

[Rippthrough 98]

Actually our FS car has an aluminium airbox and that resonates almost as loud as the exhaust. If you look at the box when you blip the throttle you can see the sides suck in!

 

If they've done it right it should be helping though