Airbox restriction 1hz turbo

[crunk81us]

Hi all

Starting turbo install soon (waiting on hoses) I am wondering what people have been using instead of standard airbox (which looks super restrictive to me) I will be wanting a snorkel soon too. Am thinking 4 inch snorkel to airbox then 3 inch to turbo?

Using a gt2860rs and a large front mount cooler

I dont want to spend mega dollars something simple would be nice.

EDIT: Its a hzj105r

[Turoa]

I use the standard air filter box and running 15psi, it makes no difference whether I run it with no airbox to having the box on (noticeable difference anyway). I do have the turbo box though, not sure if they are different to the non turb ones?

[Kitika]

I made up an airbox and put a pod filter in it and hooked my 4inch snorkel to it. It made a huge difference to my rig. Theres a bloke on offroad80s that put a 3 inch podfilter into the standard airbox(not using the top hat just a pod through the side of the airbox) and got big gains on his turboed rig from the big drop in egts. Put it on a dyno and disconnect the airbox and you'll notice a difference.

[Z()LTAN]

I built my own all 4" into the turbo, with a massive uni filter

[crunk81us]

Hi Zoltan, read thru ur build thread the other day.. kickass 70! I liked the look of urs, but that is outside my capabilities.. maybe see if i can find someone who'l' fab it up for me..

I definately want a better flowing box.. will stick a 3 inch pod on turbo to start, but i like water so I will need something better quickly

[fumduk3]

have a disco potato on my 80 series 1hz and i have maxed the pump out. im running 12psi and seems to go great with next to no smoke on acceleration or loaded up/lugging cos it boosts so fast. i put a pod on to the front of the turbo to see iff it would make a huge difference and only noticed a slight improvement and got a induction noise similar to 1 million bats or demons screaming out of the gates of hell coming to kill me.......it was louder than my exhaust,engine noise and cd player and slightly embarrassing so i put it back to stock when i got home. maybe if you go pod definitely put it in a custom box enclosed then to a 4 inch snorkel to quieten it i was surprised at how loud it was.

[crunk81us]

will do a 3 inch pod to start with.. (because i have one..) then hafta figure out a proper airbox... I don't want it to be LOUD!
(loud is ok... just not LOUD!!!) lol

[bj on roids]

3" is more than sufficient with that motor.

[Z()LTAN]

Dont be so sure mate, mine didnt like the 3" pod i had on it.

[Kitika]

Biggest is best.

[crankycruiser]

I modded my airbox so that i have 4" in and also modded the lid so thats 4" out..

was pretty easy to do and now gets plenty of air with the 4" snorkel

[bj on roids]

Dont be so sure mate, mine didnt like the 3" pod i had on it.

This may have been due to another factor, such as pod quality. Quite often they are rubbish.

There is some websites on fluid dynamics. Your flow rate will likely be in the vicinity of 300 cubic feet per minute, at full noise, running arounf 10 pounds of boost, for a 6 cylinder diesel. My motor is nearly 4 times that at full noise.

There is no equation, formula or relationship that will calculate the "maximum flow allowed" in a pipe.

For a given fluid, given pipe diameter, given pipe length and given flow, there is a specific pressure drop. Then it becomes a matter of:

Can your system tolerate that pressure drop? If not, then you need a larger diameter.

Good charts for comparison:

http://www.engineersedge.com/pipe_flow_capacity.htm" onclick="window.open(this.href);return false;

I agree the bigger the better, and 4" does look cool, BUT... 2-2.5" is probably sufficient for most diesels. (3" is the minimum I would use on a landcruiser)

[Z()LTAN]

Yeah thats pretty much what i had, but when building my intake i took into account the fact that i was going to see 4500-5000 rpm in bursts with the idea of running around 25psi boost.

Last thing i wanted was to spend time building something 'just' good enough and find down the track that it was no good.

Another thing to think about is responce time, when under heavy acceleration all that air is going from slow to very fast in a split second, you get alot of air pulsing in all directions as all the air molecules try to align in a stream. An intake that flows ok at revs may not always flow well in that instance.

I know this effect is almost un measurabe but when one is trying to get a wide high power range out of their engine you dont want to go cutting corners.

[crunk81us]

I like your snorkel crankcruiser! where did you get that made?
I also like your 4 inch mod for the airbox, that is exactly the type of simple low cost idea I was after
What filter do you run in there? unifilter or something?
I bought a 4 inch snorkel head, so I guess I'm definately going 4 inch now

[crankycruiser]

I like your snorkel crankcruiser! where did you get that made?
I also like your 4 inch mod for the airbox, that is exactly the type of simple low cost idea I was after
What filter do you run in there? unifilter or something?
I bought a 4 inch snorkel head, so I guess I'm definately going 4 inch now

thanks man a mate tigged it up for me, I run a K&N filter, have done for about the last 8 years and never had a problem with it.

I didnt know u could get a 4" head!? I probably would of gone that way if they look and good?

[bj on roids]

I like your snorkel crankcruiser! where did you get that made?
I also like your 4 inch mod for the airbox, that is exactly the type of simple low cost idea I was after
What filter do you run in there? unifilter or something?
I bought a 4 inch snorkel head, so I guess I'm definately going 4 inch now

thanks man a mate tigged it up for me, I run a K&N filter, have done for about the last 8 years and never had a problem with it.

I didnt know u could get a 4" head!? I probably would of gone that way if they look and good?

They are only like $80!!

I bought a few of them!

[biegetroopy]

very interesting thread ive just finished my turbo project [gt2876r] the turbo has 4" inlet ive reduced this to 3"then its down to 2 3/4" on the airbox i disconnected it last night from the airbox so straight 3" and it didnt seem to make a lot of difference,still needs to be run up on a dyno seems to run out off puff at about 120k,s anyway still a work in progress i guess

[bj on roids]

Yeah thats pretty much what i had, but when building my intake i took into account the fact that i was going to see 4500-5000 rpm in bursts with the idea of running around 25psi boost.

Last thing i wanted was to spend time building something 'just' good enough and find down the track that it was no good.

Another thing to think about is responce time, when under heavy acceleration all that air is going from slow to very fast in a split second, you get alot of air pulsing in all directions as all the air molecules try to align in a stream. An intake that flows ok at revs may not always flow well in that instance.

I know this effect is almost un measurabe but when one is trying to get a wide high power range out of their engine you dont want to go cutting corners.

25psi
4.2L
Single Turbo,
2 Valves per cylinder
5000rpm redline.

284 cubic feet per minute.
0.155 cubic metres per second.

Im moving nearly 4 times that amount of air, through 4" and having no restriction problems??

Yep, you would have been fine with the stock intake.

If you want me to work out the exact numbers give me your a/f ratio, and work out your intercooler losses, my best guess has it somewhere around 220-320cfm. Still well within the range of a well setup 3" intake.

Keep in mind, intake length and amount of corners is pretty important too.

Most importantly is to have a short and straight run as possible of course..

[bj on roids]

very interesting thread ive just finished my turbo project [gt2876r] the turbo has 4" inlet ive reduced this to 3"then its down to 2 3/4" on the airbox i disconnected it last night from the airbox so straight 3" and it didnt seem to make a lot of difference,still needs to be run up on a dyno seems to run out off puff at about 120k,s anyway still a work in progress i guess

You would probably find that a Bellmouth straight onto the turbo inlet, with a fan pushing into it on a dyno will make a difference.

But dont panic, about the step downs.. If you want more power, just run another half a psi, that will cover off on any restrictions.

[Kitika]

Yeah thats pretty much what i had, but when building my intake i took into account the fact that i was going to see 4500-5000 rpm in bursts with the idea of running around 25psi boost.

Last thing i wanted was to spend time building something 'just' good enough and find down the track that it was no good.

Another thing to think about is responce time, when under heavy acceleration all that air is going from slow to very fast in a split second, you get alot of air pulsing in all directions as all the air molecules try to align in a stream. An intake that flows ok at revs may not always flow well in that instance.

I know this effect is almost un measurabe but when one is trying to get a wide high power range out of their engine you dont want to go cutting corners.

25psi
4.2L
Single Turbo,
2 Valves per cylinder
5000rpm redline.

284 cubic feet per minute.
0.155 cubic metres per second.

Im moving nearly 4 times that amount of air, through 4" and having no restriction problems??

Yep, you would have been fine with the stock intake.

If you want me to work out the exact numbers give me your a/f ratio, and work out your intercooler losses, my best guess has it somewhere around 220-320cfm. Still well within the range of a well setup 3" intake.

Keep in mind, intake length and amount of corners is pretty important too.

Most importantly is to have a short and straight run as possible of course..

I think your calculations are a little off going by this calculator.
http://www.lovehorsepower.com/CFM1.htm" onclick="window.open(this.href);return false;

[crunk81us]

4 inch snorkel head $36 @ local truck parts store. looks just like a huge safari one, plastic seems a little thin compared to the 3 inch ones I've seen.

[Z()LTAN]

Yeah thats pretty much what i had, but when building my intake i took into account the fact that i was going to see 4500-5000 rpm in bursts with the idea of running around 25psi boost.

Last thing i wanted was to spend time building something 'just' good enough and find down the track that it was no good.

Another thing to think about is responce time, when under heavy acceleration all that air is going from slow to very fast in a split second, you get alot of air pulsing in all directions as all the air molecules try to align in a stream. An intake that flows ok at revs may not always flow well in that instance.

I know this effect is almost un measurabe but when one is trying to get a wide high power range out of their engine you dont want to go cutting corners.

25psi
4.2L
Single Turbo,
2 Valves per cylinder
5000rpm redline.

284 cubic feet per minute.
0.155 cubic metres per second.

Im moving nearly 4 times that amount of air, through 4" and having no restriction problems??

Yep, you would have been fine with the stock intake.

If you want me to work out the exact numbers give me your a/f ratio, and work out your intercooler losses, my best guess has it somewhere around 220-320cfm. Still well within the range of a well setup 3" intake.

Keep in mind, intake length and amount of corners is pretty important too.

Most importantly is to have a short and straight run as possible of course..

I think your calculations are a little off going by this calculator.
http://www.lovehorsepower.com/CFM1.htm" onclick="window.open(this.href);return false;

That calc gives me 850 cfm @ 5000 over 600 @ the beginning of redline. Im glad i went 4" lol

[bj on roids]

Yeah thats pretty much what i had, but when building my intake i took into account the fact that i was going to see 4500-5000 rpm in bursts with the idea of running around 25psi boost.

Last thing i wanted was to spend time building something 'just' good enough and find down the track that it was no good.

Another thing to think about is responce time, when under heavy acceleration all that air is going from slow to very fast in a split second, you get alot of air pulsing in all directions as all the air molecules try to align in a stream. An intake that flows ok at revs may not always flow well in that instance.

I know this effect is almost un measurabe but when one is trying to get a wide high power range out of their engine you dont want to go cutting corners.

25psi
4.2L
Single Turbo,
2 Valves per cylinder
5000rpm redline.

284 cubic feet per minute.
0.155 cubic metres per second.

Im moving nearly 4 times that amount of air, through 4" and having no restriction problems??

Yep, you would have been fine with the stock intake.

If you want me to work out the exact numbers give me your a/f ratio, and work out your intercooler losses, my best guess has it somewhere around 220-320cfm. Still well within the range of a well setup 3" intake.

Keep in mind, intake length and amount of corners is pretty important too.

Most importantly is to have a short and straight run as possible of course..

I think your calculations are a little off going by this calculator.
http://www.lovehorsepower.com/CFM1.htm" onclick="window.open(this.href);return false;

That calc gives me 850 cfm @ 5000 over 600 @ the beginning of redline. Im glad i went 4" lol

With no fuel input numbers, no horsepower calculation, no mixtures???

I would say it leaves a bit to be desired.

[bj on roids]

How much power you making by the way?

What fuel mixture?

[Z()LTAN]

no idea lol.

It was 108kw @ wheels @12psi

[Kitika]

Why would fuel mixture etc affect the cfm? A 4.2 litre diesel engine is going to suck in a certain amount of air at a given rpm regardless of what amount of fuel your injecting into the cylinders and then force 25psi of extra air in and it is going to be drawing in huge amounts of air.