There is some mods that I will talk to the factory about but all in all I am happy if they couldnt change anything.
The price is not an issue for me but transport even though it came down from where it started I think there is room to move.
I will let you know as things progress.
On #413's 'maiden run' with the factory standard Cummins and original Oka air filter the fuel consumption was greater than with the Perkins, as cruising speed was increased so did fuel consumption. eg. with the Perkins highway cruising gave around 16.5 l/100Km at an average 90-95 Km/hr. With the Cummins this became 19-19.5 l/100Km. At lower speeds and using 4th instead of 5th better consumption was attained ie. loafing down the Strezleki Track at 75-80 k's got around 16.5 l/100Km.
Early in the trip and sitting on 105 k's and not really paying attention to the fuel gauge I actually ran out of fuel at exactly 450 k's from a full tank. A pretty poor result. Well, that's what shakedown runs are all about I suppose. So after nearly 10,000 K's of trying various cruising speeds and gear combinations I knew pretty well what the fuel consumption was under different circumstances. Unfortunately I couldn't do much about it even though I figured early on that taking the cover off the air cleaner would be a good thing to try but as we were mainly outback off road/dirt road I wasn't game.
The proof of the pudding was the 'home run' down the Calder/Sunraysia Hwy from Mildura to Home, a run of around 720 Km via Ballarat and the Queenscliff/Sorrento ferry.
I removed the air cleaner cover after re fuelling in Mildura and headed south, I changed tanks just south of Ballarat at 500 Km and the improvement in power/driveability was noticeable from the start. We got 16.5 l/100km sitting on 93 km/hr or 1950 rpm on 325/85 R16 Michelin XML's. On the more congested run from here to home (220 Km) we got 16.8 l/100Km. IMO on the more direct Calder Hwy the consumption would have been even better. Even more so with less 'aggressive' tyres.
The point of this 'long winded' story is to point out that the restriction was obviously poor air flow especially the small snorkel diameter standard in the Oka.
I've been waiting for an Acco air cleaner to try but hopefully your solution will be a success so I watch with interest.
The point here is that the restriction in the factory snorkel setup makes a significant difference when air consumption requirements are increased and IMO the air cleaner Martyn is working with could go long way to resolving this issue.
I read somewhere that you were in Tassie, You will get better fuel consumption for a number of reasons being. you installed the turbo without changing fuel settings so this will give you a leaner mix which unlike a petrol engine a diesel engine can run lean without any detrimental effect but too lean I am not sure. Being in Tassie the air is denser and more humid also colder so in simple terms more power or the same with less pressure on the accelerator all in all better economy.
The opposite is true for the hot dry climates.
- Posts: 646
mort wrote: Hi Tony,
I read somewhere that you were in Tassie, You will get better fuel consumption for a number of reasons being. you installed the turbo without changing fuel settings so this will give you a leaner mix which unlike a petrol engine a diesel engine can run lean without any detrimental effect but too lean I am not sure.
1) a petrol can be leaned out, and the last few years in F1 that have been fuel limited, so to get a better "Brake Specific Fuel Comsumption" (BFSC) one then needs more air.
(When air restricted and not fuel restricted then adding fuel gets more power at the expense of BSFC.)
The other example is in aircraft... both require running lean of peak (LOP), and most engines are tuned to run rich of peak (ROP). Does does not want to go through the peak to get lean at wide open throttle (WOT) as that is where detonation is most common.
2) However I am not sure how the turbo alone will give a leaner mixture? How is the mixture determined? I assume mechanically, and there is more boost at lower RPM and also that the engine is running boost at cruise?
- Peter and Sandra OKA 374
- Posts: 1160
More air means more fuel can be burnt and getting the exhaust away quicker with less restriction gets rid of heat quicker.
The turbo can be changed to a different flow rate and also changed to give boost lower or higher in the rev range.
Fitting an intercooler drops intake air temps which are increased considerably when the turbo compresses the incoming air never mind the heat picked up from the turbo itself and the intake trunking.
OKA 374 LT Van, converted to camper/motorhome,
400ah Lithiums, 680w solar, diesel cooking heating and HWS,
Cummins 6BT, Allison 6 speed auto, Nissan transfer.
Yes you are correct sort of ... an F1 I cannot comment on as I have no knowledge off except that they go fast and rev at that is ridicules and at the end of each race the engine is stripped down and rebuilt.
Planes on the other hand I have some knowledge off, the idea of running rich or lean is similar to any other engine so on takeoff, climbing or landing so when power is required the pilot will manually set to rich for power but once reaching cruising altitude he will then set to a lean mix, it is based on the cylinder head temp which is the same for the Oka and the reason to install a pyro gauge. On aircraft if you run too lean you will stall and too rich you will seize either way you fall.
Using Tony's as an example we would assume it was tuned to an ideal air/fuel mix so he then installed a new turbo and did nothing else that turbo is now pushing more air in without changing the fuel hence the leaner mix, if he wanted to get max power he would need to reset injector pump.
Fuel consumption can't be measured accurately in any road test simply because the several variables can't be controlled. Terrain, altitude and direction profile, road surface, wind direction and speed, window open of closed, aircon or heater on or off, electrical load, ambient temperature, tyres, interference from other road users, driver skill and attitude and probably the main one which is how to measure fuel used.
Fuel consuption can be measured to several decimal places using a dynamometer, but of course then the complaint is that it bears little resemblance to real-world situations (the "s" being because everyone's situation will be different)
Gauge shows near to empty ==>>> Switch to the other tank ====>>>> fill the first tank and hand over the credit card. Dollar amount, litres pumped and Odometer reading all irrelevant.
Yes, might even get around to doing it one day - or just screw the adjustment in half a turn as someone suggested.
if he wanted to get max power he would need to reset injector pump.
- Posts: 646
One needs a fuel flow to fit he consumption part of fuel consumption.
For the "brake specific" part of BSFC, one needs a power measurement.
Speed and force do it but as mentioned there is tyre pressure wind load etc...
A strain gauge of a shaft or motor mount torque or some "load cell"" can give the force part.
But I agree with your posted 'tautological' conclusion of "it iis what it is", so while it would be technologically interesting who cares.
Diesels are a different beast, and the turbos run on engines with 15-20:1 compression ratios.
The thing I hear with petrol engines are that turbos get better mileage because they recover the energy in the heat.
A high compression engine running at WOT at max torque is where the lowest BSFC usually happens.
Any lowering of compresssion, or opening the exhaust value early to get more exhaust heat to spool e turbo, or retarding of the spark to avoid detonation all lower efficiency. Diesels do not work Thi sway, unless there is some gas LPG which iburns more like petrol.
I suppose people must use lambda gauges, but have no clue... I need to GTS it.
What that has to do with airfilters I do not know...
Are the new air filters better?
New air filter installed and all working as expected.
I have given the elements to a supplier to see if he has or can get the replacement elements if not they are an off the shelf item for the manufacturer so readily available ( in Europe and U.S. ) if not an off shelf item here then maybe if wanted could order say 2 elements as spares for future....wait and see.
Ok the element is/can be replaced with a Donaldson P130884, P789077, WA1028 or there is other brands that will replace the factory std so no issues.
I am now waiting for a reply to the changes and the final price which will include silicone bends from filter to turbo.
Should not be long now.
I have received from the factory confirmation of the changes which they can do except one that being the inlet at the front in line with the snorkel, the reason is the air flow inside the housing will change and affect performance so still at the back like normal but for ease of installation it is rotated to the left where there is more room.
The final price is $361.00
This is made up of Filter $181.00
Silicone fittings from filter to turbo $35.00
The filter all metal is a good price, the silicone bends x 5, I had to purchase for the filter that I just put in and 1 bend cost $40.00 in Perth. The shipping started at US$230.00 to which I told them it was a deal breaker and quoted what I was paying for turbos which are heavier but smaller so went to a number of shipping agents to get it down and its not the weight but size.
I have got a number of pre orders and although there is a minimum I dont believe that the price will change for larger orders.
If you want silicone bends for intercooler let me know and it can be added into the box.
Over the last week I have had a number of Phone calls or emails regarding ordering the filters and with a few questions as they are similar questions I thought I would put up some with my answers/comments.
Do I need to change my filter.
Short answer no but if you want to get the best performance and economy from your engine then yes.Its like when you go for a walk breathing is normal and steady but pick up the pace and you not only burn up your energy reserves but you need more air, restrict the air and you dont do too well.
Will the filter be big enough for a 6BT or similar.
Yes it was sized to suit any upgrades that has or may happen.
Is it an easy fit and install.
Yes I dont like complicated or hard, basic tools ie tape measure and pencil, tin-snips left and right hand, angle grinder, drill spanners and screw driver is about all.
If I had an old one from a truck is it ok.
Yes if it can fit in the space and is bigger than std why not.
I did go looking at the truck wreckers when I did this last turbo install and only found 1 that would have worked, it was from an ACCO and was a Donaldson so mounting brackets were similar it was a little bigger than std oka and sized for a 160 HP. They wanted $220.00 for it the biggest problem was that it only had a single filter which would be ok if staying on bitumen but the owner wanted 2 filters add the cost of cleaning and painting and new filters why bother.
There is a lot more truck wreckers in the eastern states so maybe you will have better luck finding a duel filtered one at a reasonable price that wont be too difficult to fit.
The other thing to consider is that old also means it may miss out on features and certainly one is if you look at one of the photos above you will just see some vanes/fins inside at the back this is to allow the air to spiral around and cover the entire filter but also any dust or water can be thrown to the edge away from the filter.
Is there any other advantage in having a larger filter.
Other than allowing the engine to have as much air as it needs without struggling a bigger filter means if you are in a dusty environment it will take a lot longer to clog up.
Any other questions just ask.
After upgrading to the Cummins 6BT it became quite obvious that the original Oka filter is inadequate for the larger capacity engine. The engine was not 'breathing' adequately or running as good as it should. Fuel consumption was significantly higher than it should have been.
Oka Paul provided me with the Acco filter to try and it has exceeded my expectations
The original Oka setup is a 90mm snorkel feeding air via a 'squashed' aluminium S bend (IMO an appalling piece of automotive design but beautifully engineered) necked down to 75mm into the air filter housing with restrictive baffles to generate a 'cyclone effect' to help remove dust and with a 75mm outlet to the turbo.
The 'improved' setup provides better air flow in every way, it is still a cyclone type filter but uses a plastic shroud and fins on the filter itself to 'generate' the cyclone. The only thing that stays the same is the external air inlet shroud itself which has an inlet area of approx. 95 sq cm but is now pointed forward (like the NT) to provide a 'ram air' effect, particularly at higher speeds.
The oval snorkel inlet is now 95mm X 120mm (previously 80mm X 95mm) or about 40% bigger. The replacement snorkel is 100mm vs. the old 90mm or about 25% (cross section area) larger. There is no horrible bent aluminium plenum/restriction down to 75mm but a 'full flow' 100mm pipe all the way through to the air cleaner housing for a whopping 80% improvement in size and improved air flow. The outlet to the turbo is now 90mm (was 75mm) but fed with 100mm fittings as this fits my Cummins Holset turbo which has a 100mm inlet flange, for a 45% improvement in cross section area.
I used rubber (and PVC) bends as I was not happy with using soft silicon bends on a 'suction' line. The rubber is firmer and about twice the thickness of the silicon and about half the cost. the PVC is about 1/10th the cost but a bit harder to work with.
The 10" mounting bands for the Donaldson filter have the same mounting centres as the original 9" Fleetguard bands and with 8mm inserts installed bolt straight in using the existing holes for a 'perfect' fit.
If you're not fussed about keeping a circular cutout in the coffin panel and are OK with an upside down U cutout then installation is a lot easier. ie. there's no need to trim the body mount wing (or trim the rear external flange of the air cleaner housing) or to cut and bend the mudguard flange as the filter assembly is just slid in from the front. The 'foofer' valve thingy is the same size connection on both housings. I chose to keep the original Oka circular cutout look.
It was a bit of a tight fit but very doable, the main tools needed are the odd spanner and 100mm angle grinder with a 1mm disc. When it came to cutting the the larger circle in the coffin panel I used a Dremmel with a 30mm cutting disc which I also used to enlarge the cutouts where the original snorkel saddles were re used.
I used 100mm exhaust pipe for the new snorkel and the connection between the 100mm PVC right angle fitting from the filter housing inlet to the 100mm rubber 90 degree bend that fits perfectly through the opening in the floor behind the driver to pick up the bottom of the snorkel. There is no need to cut the floor or the panel behind the drivers seat.
The 'new' air filter elements are Donaldson. P900 226 (main) and P900 228 (safety). I used the Fleetguard equivalent AF4627KM (main) which at around $50 is cheaper than the Baldwin filters I'd been buying for the original Oka air cleaner setup. A safety filter equivalent is Baldwin BAF0228.
The proof of the pudding as they say is in the eating.
Kaye and I did a 500 km test run to check out the Granny Flat camp site. From where we live in west Gippsland it is a winding and hilly run via Healesville, Kinglake, Mansfield and Jamieson to get there and our route home via Woods Point, Mt. Matlock and Warburton gave plenty of 3rd and 4th gear work plus a bit of 2nd gear. Power and drive-ability definitely improved and used 85 litres for 497 km which is 17l/100 km which I reckon is very good considering the terrain covered.
I did another run last week. Home to Moama via Calder Hwy through Melb am peak and via Heathcote etc and home via the Hume Hwy just missing pm peak but still heavy going through Melb. for a total of 614 km and 99 litres. Sitting on just over 2000 rpm or about 95 km/hr on basically main hwy and b class undulating hwy this gave approx.16.1 l/100 km which is around a 4l/100 km improvement and with better performance than with the old air cleaner setup.
IMO the original Oka air setup is at best 'barely adequate'. With the greater air requirements of a bigger capacity engine or larger turbo optimal performance will not be achieved without better air flow, this includes removing the restrictive original Oka baffled muffler and replacing it with an unbaffled type.