Brain fart - supercharging a 2.8Ltr diesel hilux

[boxh34d]

Ok, I've been thinking (if you can call it that) of whether there would be any point of using a PD blower to supercharge my LN106 Gutlux. Now, obviously the turbo route is far more common, with many aftermarket kits available for my engine, but I can't help but wonder if the blower option would be worthwhile. A few good points I can think of are:
Low rev nature of engine means blower speeds are more easily managable; No throttlebody present to limit airflow, so I assume a bypass valve system is not needed for low speed running; The engines airflow stays reletively linear like the naturally aspirated motor, so tuning of the mechanical fuel pump should be fairly easy compared with a turboed system, which really should have a boost compensator to be effective.
The main bad point I can think of immediately is the drag of the blower. Due to the low power nature of a diesel engine, if it takes 15HP to drive a blower on an engine that is only going to make 20HP over standard, then it is hardly a good option.

As for sizing of the blower, I'm a bit stumped. I don't really have any idea on how to work out how much air I'd need at what sort of pressure, to make any more power.

The engine in question is the 'mighty' Toyota 3L diesel, a 2.8litre 4 pot, which commonly make around (I can here the laughing already) 50 odd HP at the tyres. Of course this varies hugely with things like tyres size and diff ratios (can vary a lot with 4WD's), but I guess I'm just looking for something relative.
Looking at it very simply, diesels are commonly said to have a VE of around 90%. So, 1.4L of air pre rev * 0.90 VE * 4000RPM = 5004Litres of air per minute, or about 175CFM.
If we say that it takes 5000 L/min to make 50ish HP, can it be assumed that it will take 7000 L/min to make 70ish HP?? Is it that simple to get a ball park kind of figure, or is there a whole lot of shit that needs to be taken into account?

Looking for any comments or guidance.
Thanks in advance.

[Harreh]

You're already putting way to much thought into this.

This is toymods and you're discussing superchargers. The obviously solution here is an SC12. Dont think just do it. Then if it works you get an SC14 that goes in your garage that you forever talk about installing.

In all seriousness I think an SC12 should go alright

[Duk]

I would highly recommend a decent intercooler because the supercharger will always be compressing the air regardless of what how you're driving, it will always be heating the air.

[mattysshop]

my bro in law up north QLD (mining town) has but a dirty little 2L into his hilux... and strapped an SC12 to it.. hasn't finished it off yet as he had the SC piping the wrong way around lol.... but he has spoken to a few deisel tuners up there and all they are saying is "yeh mate weve done somthing similar, just turn the injector pump screw half a turn and she'll be right" but he has got a piro meter in the headers so he can keep an eye on the ex temp to make sure on that.. but thats pretty much it..

the insane torque that a deisel makes at low RPM you would probly find that the drag of a SC won't affect it too much... power is a mere calculation of torque and RPM... RPM is what a deisel does not have.. but has bucket loads of torque... boosting increases the torque dramatically which is what you will feel straight up!!

[Billzilla]

Looking at it very simply, diesels are commonly said to have a VE of around 90%.

FWIW we've got a boost gauge on our turbo diesel Pajero (I call it The Squid, 'cause when it takes off it leaves a big black cloud behind it) and it's very different to a petrol-engined car.
Naturally it sits on zero with the engine off, but when you start it, it still sits on zero because of having no throttle butterfly. Then as you accelerate the boost starts to come in, with more throttle giving a bit more boost. At 60 km/h constant speed it shows about 2 - 3 psi boost and at 100 km/h it shows 7 psi. The odd thing is that when you get off the throttle completely from 100 km/h and let it slow, it initially shows 2 psi still and that gradually tapers off back to zero again as the engine revs drop off. I can even get a little boost in neutral by revving it.

[TTV8RA23]

Will be interesting to see this go my mate got a kit 90% made for his 5L diesel extra tensioners and all sorts blower mounts and everything for an SC14 but then changed plans and ended up putting a VVTI 1UZ and 6 speed nissan 350z box. Im pretty sure all the bits are still lying round in his shed. I would have thought you would go SC14 straight off the bat wouldnt you? I mean a SC12 is made for a 1600cc motor and we are talking 2800cc i know its a diesel motor though does it make that much difference?
Cheers
Simon

[Hiro]

Will be interesting to see this go my mate got a kit 90% made for his 5L diesel extra tensioners and all sorts blower mounts and everything for an SC14 but then changed plans and ended up putting a VVTI 1UZ and 6 speed nissan 350z box. Im pretty sure all the bits are still lying round in his shed. I would have thought you would go SC14 straight off the bat wouldnt you? I mean a SC12 is made for a 1600cc motor and we are talking 2800cc i know its a diesel motor though does it make that much difference?
Cheers
Simon

A 1600cc engine yes, but one that is revving to almost 8000rpm...your diesel will probably be sitting at half those revs if not less. The SC14 was used on 2.4L petrol Taragos, which is a good comparison to the higher-revving but smaller capacity 2.0L 1GGZE which also used the SC14...

[Supra967]

i know its a diesel motor though does it make that much difference?
Cheers
Simon

Think power when comparing turbo/sc. Diesels are usually lower power output- the 4.5L turbo landcruiser would give a 7MGE a run for its money on a dyno. Because they are low power, you can use small chargers without running out of breath, and small chargers means early spool. Above diesel makes full torque from 1200rpm to its peak of 3400.

I wonder if there'd be much comparison between a supercharged and turbo charged diesel?

[boxh34d]

Harreh: see posts below.

Duk: Really depends on blower size and pressure. They can actually run quite cool at low pressure, but I will be looking at this depending on what size blower, and how it is going to have to run in such a setup. Definately on the cards if its needed.

mattysshop: I'd love to see a couple of pics of the mounted setup to see how the brackets and pulleys have been done.

billzilla: Certainly not disputing that turbos are the way to go, as the response available is nothing comparable to a turboed petrol. However, without the boost aneroid (sp?), tuning accurately is almost impossible. Without it they generally either run rich at no load, and correct at load making good power, or nice at low load, and lean at load making no power.

TTV8RA23: I don't suppose said mate would be interested in offloading these parts?
I had thought that the SC14 would be a good match, as like has has been said, 1400cc per rev, on a motor that revs to 8000rpm, compared with my 2.8, which NA uses less than 1400cc air per rev, and only revs to 4000rpm should do it quite easily. I'd love to know some details on delta T and power across the map of one, though I can't seem to find that kind of info.

Hiro: see above.

Supra 967: How do you mean? As in same airflow and pressure using either the turbo vs a blower? At low boost, I would think they could be quite close, but as soon as boost starts getting up higher, the turbo would most likely streak away, as this is when blowers usually start to chew big power to drive.
Take a look at capa's site, and have a look at the graphs of the eaton blowers. Look at the increased power consumption and heat output at 5 psi vs 10 psi for a very small increase in actual airflow.
http://www.capa.com.au/eaton_m90data.htm

Wow, that turned out to be a long reply.
Thanks for the input so far everyone, keep the discussion coming.

[TTV8RA23]

Hey mate i will try get hold of him today. He now lives over the ditch with you guys but should be able to raid his olds shed and find the bits for you. Shipping would be expensive though and im not that keen to send it cos it is alot of mucking around but for the right price im sure we can sort something.
Cheers
Simon

[Supra967]

Supra 967: How do you mean? As in same airflow and pressure using either the turbo vs a blower?

Me being clear as mud again?

I meant just generally, not comparing turbo TO sc. Power is a result of the flow rate of air given by the charger.

[boxh34d]

Hey mate i will try get hold of him today. He now lives over the ditch with you guys but should be able to raid his olds shed and find the bits for you. Shipping would be expensive though and im not that keen to send it cos it is alot of mucking around but for the right price im sure we can sort something.
Cheers
Simon

That would be good if you could find out, no great hurry though. I just looked at your location, could indeed be a problem. On a side note, I thought it was a nice spot Whakatane, was there for a couple of days in May.

[love ke70]

mate, in all honesty, theres a reason everyone turbos diesels, the hassles in fitting the supercharger are not worth the efforts.

there are people in the know on outerlimits that have done both and say turbo is the way.one that comes to mind is a guy that owns a supercharged 4.2 patrol and a turbod 4.2 patrol, and at the same boost, says the turbo flogs it across the board, apart from a few seconds off the line.

my patrol sits on 9 psi just cruising on the highway, boost compensation for fuel is overrated, theyre always on boost, and they run at any given AFR so who cares if its a bit rich down low, you wont break it. i can get 2-3 psi free revving the motor, with hte right sized turbo lag does not exist.

[mattysshop]

i tend to agree with Love.....

we've had some through the workshop for cooler/dump/ex/intake setups... and they just wind in the boost (round 20psi)... power increases a fair bit (from like 80 to 150hp at the wheels on a 3L hilux hahaha) BUT there is enough torque to 'chatter' 33x10.5's when it comes on boost in 4th...usually leaving a mack style deisel cloud behind...

[love ke70]

before i put a tonne of gear on the back of mine, it would turn 35s in second, and try in third.

if you want less lag, more power and no black smoke, look into lpg injection too. D-GAS is what im running, or go diesel-gas technologies, just dont ask which is better, theres been too many arguments already none of them are ideal