Thread: Britpart/Wolf RAI on 4BD1-T

Tell me if I'm getting too much off topic here, but if you take that 500CFM and look for a suitable airfilter housing for it you get something like a Donaldson B120470 with 8"H2O restriction at 555CFM and 6" at 475CFM.
But its HUGE, 13" diameter and nearly 2' long with inlet/outlet of 6" and 4" respectively.
http://www.donaldson.com/en/catalogs/engine/061524.pdf
Obviously not practical unless you're Roothy and want to mount it on the roof or front guard.

I think the rating of the restriction indicator on my filter housing is 10"H2O, but that never triggers if I run without the snorkel.
Filter housing is a Fleetguard AH19066 which is rated at 254CFM at 10"H2O restriction, so I deduce that my engine isn't using that much, so nowhere near what in theory it could use. I've got standard governor RPM, T25G turbo and max EGT's of around 700C.

So unless I've stuffed up somewhere (which is highly likely ) something doesn't correspond between the theory and practical.

EDIT: Yup, I stuffed up. I should probably stick to drinking coffee and eating donuts - I usually get that right.....
My restriction indicator is actually 25"H2O (not 10"). A rough extrapolation of the Fleetguard graph gives about 500CFM at that restriction so I'm using less air than that (as I'd expect with no intercooler and not particularly much extra fuel).

Steve

Originally Posted by inside

It doesn't matter what the vehicle is doing it's all about the engine and how it is working. I guess 3500 rpm was chosen as the maximum rev limit for a 4BD1.

FWIW I would not use one of those snorkels either. Way too small.

I think it will be relegated back to the Series with the Rover six cyl.

But the air flow discussion is interesting.

Onto the filter housing, I thought a part of the calc was to get a high enough air flow speed so that the cyclonic effect worked. If the pipework is too large dia the airflow speed is low and so is the cyclonic effect reducing the centrifugal forces on the particulate matter.

Originally Posted by Lotz-A-Landies

...Why are you using the RPM at 3.5K? Is that the max RPM of the engine? (My calc had the engine RPM less than 3K in 5th at 100KPH.)

Worst case scenario (redline). If you design to that you will reduce restriction across the board [whole rev range]. You can convert the equation to metric/SI easily, however all the lookup tables are in CFM and "H2O.

Originally Posted by steveG

Tell me if I'm getting too much off topic here, but if you take that 500CFM and look for a suitable airfilter housing for it you get something like a Donaldson B120470 with 8"H2O restriction at 555CFM and 6" at 475CFM.
But its HUGE, 13" diameter and nearly 2' long with inlet/outlet of 6" and 4" respectively.
http://www.donaldson.com/en/catalogs/engine/061524.pdf
Obviously not practical unless you're Roothy and want to mount it on the roof or front guard.

I think the rating of the restriction indicator on my filter housing is 10"H2O, but that never triggers if I run without the snorkel.
Filter housing is a Fleetguard AH19066 which is rated at 254CFM at 10"H2O restriction, so I deduce that my engine isn't using that much, so nowhere near what in theory it could use. I've got standard governor RPM, T25G turbo and max EGT's of around 700C.

So unless I've stuffed up somewhere (which is highly likely ) something doesn't correspond between the theory and practical.

Steve

Everything is a compromise Steve - even OEM. While it is hard to fit a larger filter assembly, it is easy to minimise pressure drop in the ducting and snorkel. The OEM filter options have a 3" inlet, so it makes sense to keep the snorkel at least at that size - with smooth transitions/bends.

Originally Posted by steveG

I think the rating of the restriction indicator on my filter housing is 10"H2O, but that never triggers if I run without the snorkel.

So when you connect a snorkel it triggers? I think the air filter and flow is often over looked here when people do their turbo conversions. Trouble is there's not a whole lot of room to fit a bigger filter under the bonnet.

I've edited that post as the restriction indicator is actually 25"H2O so makes more sense now.
But yes, it only triggers when its hooked up to the snorkel.
I should get around to ditching the corrugated duct and replacing with another mandrel bent tube section and some nice silicon joiners. Be interesting to see the difference.

Steve

Probably thinking too much now, but what might be useful is to have some actual pressure drop readings from the different intake setups that people have.
At least then we'd have some benchmarks for what a reasonable setup is.

Anyone actually done it?
Maybe I should get myself a $42 digital manometer from evilbay.....

Steve

Thanks Ben for the maths on this...
I wonder if safari come out with ratings on there snorkels or if we need to figure it out ourselves ? ATM it's a toss up for me between a safari or a 4" stainless one...

Originally Posted by isuzurover

The Wolfs are TD5s aren't they???

[snip]

Nope, 300Tdi's.