Need help designing an airbox

[touge_ae101]

Dude your design and cad skills are very impressive.

If you are able to make this product I will definately buy it. I will give my engine bay a quick measure up in the morning and you can compare it to your 4age one.

Will this design run into the problem of forcing air into the engine and possibly making it run lean?

cheers man. it won't be for a little while my welder is getting fixed atm. i'm heading back to uni next week then guna work every 2nd weekend full time so will probably be the end of march before i get a bit of free time during the week to get into something like this.

yeah as nzhorider said, it won't be enough to upset the AF ratio but if a fresh air feed is fed directly into the intake it could be enough to make the MAP or MAF sensor to get outside its limit of readings, in which case the ecu won't know what to do with itself. its unlikely but always design for the worst. one way of eliminating the risk is to not seal the pipe coming from the foglight going into the front of the airbox

@nzhorider i have yet to see a filter with 'angled' flutes if this is what you are talking about? if you know of any then that could be a possibility.

to figure out the angle at which the increased area becomes more of an advantage than the disruption of the air, it would be a lengthy test procedure as you would have to go in say 5deg intervals, keep airflow constant and measure the pressure on either side of the filter to determine it accurately. not sure if it would make too much difference in the real world cause you could already fit a filter which is much bigger than a std filter anyway.

yeah the pipercross and K&N filters are good 'inline' solutions to isolating your pod but IMO it does not get back to the advantages of having a proper airbox from my research. from analysing what makes the ARC box a good performance airbox, it is purely the volume of air closely available to the engine which gives it the advantage as the actual construction is pretty average with sharp corners everywhere and odd angles. yet it still works. these 'inline' filter isolators do a good job at keeping hot air out but don't give the engine a resoivour of filtered air readily available. if you want to see an example of this, see the design of the 'whale penis' intakes you can buy for honda engines. they work on the same principle and are known to give better response and torque.

[siren676]

So you have a 45mm pipe all the way to the throttle body?

I said pipe not throttle body. I do have quads though

Maybe the inside diameter dont know as i haven't checked, although i did need a custom adapter to fit the pod as you can see in the pic.

I now want itb's on my 5e

[touge_ae101]

I now want itb's on my 5e

oh shit that is starting to get rather serious! it would be cheaper to turbo. ha (not many times i would say that) your pipe going up to the throttle body looks to be about 60ish mm (2.5inch) and the individual runners look to be rather small maybe 40-35mm.

that runner setup looks terrible with flattened bends and not sure how it splits up the air well. might be worth looking at improving that too. not sure what other people with starlets have done.

[siren676]

Dude your design and cad skills are very impressive.

If you are able to make this product I will definately buy it. I will give my engine bay a quick measure up in the morning and you can compare it to your 4age one.

Will this design run into the problem of forcing air into the engine and possibly making it run lean?

cheers man. it won't be for a little while my welder is getting fixed atm. i'm heading back to uni next week then guna work every 2nd weekend full time so will probably be the end of march before i get a bit of free time during the week to get into something like this.

yeah as nzhorider said, it won't be enough to upset the AF ratio but if a fresh air feed is fed directly into the intake it could be enough to make the MAP or MAF sensor to get outside its limit of readings, in which case the ecu won't know what to do with itself. its unlikely but always design for the worst. one way of eliminating the risk is to not seal the pipe coming from the foglight going into the front of the airbox

...

Im happy to wait till march/april to have this started, it'll give me some time to get some money together and put the new engine in.
The new engine is only 25mm taller but throttle is still in the same place and shouldnt affect the design.

Ill have to read up on which sensor my car uses to detect flow/pressure (or one of the starlet guys will know)

[RomanV]

I disagree about the angle of the panel filter having any affect on airflow direction, if you look at the path that the air needs to take to get through the filter, it's in no way straight anyway.

Remember that (for example) a 2 litre engine with 100% volumetric efficiency, at 6000rpm full throttle sucks in 6000 litres of air per minute.

Cant really simulate this with blowing an air compressor gun to get a feel of what's happening.

Air swirls around a hell of a lot anyway, it's all fancy like.

If you want to get nazi / OCD / perfectionisnt about air intake, I would do the following:

1. Take apart the front of your car, and ensure that there's no way for air to get into your engine bay, except for into the inlet for the air intake (which you're about to enlarge considerably) and the radiator. blank off every single hole, make sure that the rubber trim on the underside of the bonnet is still there.

2. find an appropriate place to make a big hole for your air intake. If the whole front of your front radiator panel is sealed up, there should be a worthwhile pressure increase in front of the radiator panel. Buy a big (say 4") bellmouth from tweakit.net for the inlet to your air filter box.

3. Have this pipe leading to an air filter box, housing a big STANDARD air filter from a car with a big engine. In my opinion, better off replacing cheaper air filters more often, than trying to squeeze milage out of a fancy one, or reoiling one that will now most likely be getting damaged by rocks etc over time, because of your bigger air inlet.

4. Have the space AFTER your air filter as big as possible in your airbox, and buy an appropriate sized bellmouth from tweakit.net for the pipe leading to your throttle body.

5. Throw away the shitty pipe with the accoridian style bends in it that leads to your throttle body, and replace it with smooth aluminium bend pipe instead.

6. Realise that you've just done shit tonnes of work on an economy oriented engine for next to no gain, and that the major bottle neck to shoving any decent amount of air into the engine is the engine itself and/or lack of turbo charger.
Back peddle and justify your effort spent by saying "it was more of a project than anything, I wasnt really expecting any gains" As per every other single person who's done the same.

7. Buy some ear muffs to drown out the "I told you so"s and "shoulda just turboed it already" comments.

8. Admit defeat and get a turbo like everyone else.

9. No profit, but more fun/fasts.

10. Kinda serious up to point 5.

[siren676]

I now want itb's on my 5e

oh shit that is starting to get rather serious! it would be cheaper to turbo. ha (not many times i would say that) your pipe going up to the throttle body looks to be about 60ish mm (2.5inch) and the individual runners look to be rather small maybe 40-35mm.

that runner setup looks terrible with flattened bends and not sure how it splits up the air well. might be worth looking at improving that too. not sure what other people with starlets have done.

The new motor has an acis manifold 4 long skinny runners and 4 short fat runners which are used to switch where torque is produced. It is far more efficient than the useless design of the current manifold.
It will definately be cheaper and easier to turbo than go itb's

[siren676]

...

8. Admit defeat and get a turbo like everyone else.

9. No profit, but more fun/fasts.

10. Kinda serious up to point 5.

Would start here but i have just struggled to convince my dad into letting me put in a bigger engine. I have no show in hell of putting in a 1500 turbo to replace a 1300 nana spec engine.

[RomanV]

Fair enough man!

Good way to learn some new skills.

It's kinda better than just spending your youth blowing your money on beer.

Kinda.

In other news, every starlet that I've owned (KP60 and EP70) has been a rediculous amount of fun to drive, the absolute lack of power is part of the fun.

It's kinda fun having a car where you can floor it everywhere and still not get in trouble.

[siren676]

1 step at a time and i should be able to handle the power increases.

I dont buy beer, just take it from dad when he's not looking

I know what you mean with the lack of power, although mine has a bit louder than stock exhaust and I get a bit of attention from the police if flooring it. Although what it lacks in the straights it makes up in the corners.

[soopachargen]

I would look at spending the money you are going to spend on the engine on putting the entire whiteline catalogue under the car, handling gains are the ones that you are going to notice.
Once your dad isn't a limit to what you do to the car then you can turbo it.

[siren676]

I've already got the engine just waiting to get it put in. I already have a few handling mods. A whiteline adjustable rear swaybar and an ultra racing front strut brace. I am trying to find a front swaybar and mounts as mine didnt come with one.

I should be able to put a ct9 on the 5e once dads happy that i will be able to handle it. Hopefully be about 6 months or so.

[touge_ae101]

great thing with a airbox like what i have drawn - if its made from alloy then it would be rather easy to modify to take a water to air intercooler core it would provide nice short piping and heaps of volume. don't know if this i a good thing though might make it laggy? i don't know enough about turbos really.

[gt4dude]

factory intakes are shit, you can prove it on a turbocharged engine by noting the 2 - 4 psi maximum boost increase by using a pod filter, would be closer to 6psi increase with a cold air pod filter.

On another note you can spend around $500 doing a cold air intake, which doesn't really sound like good gains per dollar spent..

Sound ridiculous? Well add up the cost of 2 gauge wire, battery box, terminals, pipes, bends, couplers and clamps before you get to the actual air box construction and you're already $300 into it and haven't made a single gain yet.

Don't let that deter you though, you can buy things bit by bit until you've finally achieved your goal and its one of the easiest and most satisfying modifications you can do yourself without major tools or jacking up the car.

[Bling]

factory intakes are shit, you can prove it on a turbocharged engine by noting the 2 - 4 psi maximum boost increase by using a pod filter, would be closer to 6psi increase with a cold air pod filter.

Show us the proof then And how the intake on a turbo car relates to one on a NA car.

[DUGDUG]

Just out of interest, has anyone tried a venturi type intake pipe.

I'm getting one made up for my BT BZ Touring - basically consists of 3" pipe from plenum to 5" chamber down to 3" again and HKS pod filter at the end. Theory being air into filter going to 5" chamber = low pressure/slow/calm then to 3" = high pressure/fast to the intake plenum. The filter is going to sit directly behind the headlight where I'll try and box it off with cold air ducting.

Got the idea from a Honda whale penis intake pipe. Not gona cost me much so thought why not.

[Nuty|Mike]

Maybe the simple option could be the best ?

This looks good (sorry kiwicorolla for stealling your pic)

Engine bay looks close to the same

[gt4dude]

factory intakes are shit, you can prove it on a turbocharged engine by noting the 2 - 4 psi maximum boost increase by using a pod filter, would be closer to 6psi increase with a cold air pod filter.

Show us the proof then And how the intake on a turbo car relates to one on a NA car.

Before I had a downpipe and boost controller installed, i used the factory air box with a high flow element during winter to cure overboost, and use the k&n in the summer.

I used that to come to a conclusion that factory air boxes are restrictive hence shit and that this relates to NA cars also because the NA version of my car shares the same bottom half and fender plumbing as the Turbo version.

[wde_bdy]

Be very careful with that type of setup, wouldn't be ther first time a low mounted filter has hit a puddle and hydrauliced a motor.

Callum

[levinguy]

would be closer to 6psi increase with a cold air pod filter.

lol.

[sergei]

factory intakes are shit, you can prove it on a turbocharged engine by noting the 2 - 4 psi maximum boost increase by using a pod filter, would be closer to 6psi increase with a cold air pod filter.

What you are talking here is inability of factory wastegate of controlling boost. Yes using different intake system affects your boost, but that is secondary effect from changing of flow characteristics of whole system and does not mean you are actually gaining anything.


Better control would be is to fix boost control issue (CT20b is a very terrible at it, especially when you deviate from factory intake and exhaust system) and compare both intake system at same boost levels on same day on dyno.

People install exhaust and think that since they getting boost increase they flow better. Well wastegate is set at certain pressure and if you are getting boost increase with a modification, it means that you are changing flow characteristics in such way that wastegate becomes inefficient.