I Need More Power Scotty

[mr_sav]

OK,

My Isuzu needs more umph to get up the hills.

The 3.9 1985 110, could do with some more speed climbing hills, noting I tend to be towing one thing or another beit boat or heavy trailer.

What Can/Should I Do? Do I go for the Isuzu Diesel Turbo, or Aftermarket. I have been told by a local Land Rover Mechanic that the cost to performance ratio to fit the Isuzu Diesel is not worth it.

Note: My LR does not have factory Air, so I have reasonable bonnet space, and most importantly - The Vents.


The Engine (if History is correct), including what I have contributed equates to 300,000kms.

Or is it just not worth contemplating.

Regards,

[isuzu110]

Went through this dilemma myself with my Isuzu County...

For me, an injector pump overhaul and injector nozzle replacement made a marked improvement. I also have extractors but as they were already on the vehicle when I bought it, I cannot comment on effectiveness.

I have aircon and no vents so decided against the turbo but believe it yields a marked improvement. The guys who have done it will chime in real soon.

[stirlsilver]

I know on the 300tdi engines you can adjust the injector pump to increase the amount of fuel delivered to the engine, it's supposed to give you a bit more power. I don't have a clue if you can do that on the Isuzu engine tho. Just my two cents :D

[isuzurover]

(1) Check/Adjust timing - 10deg. BTDC is right I recall. Over time the pump timing will retard slightly as everything wears. Advanced timing usually gives better performance (but don't go too far as this won't help EGTs).

(2) Fuelling can be increased on an NA vehicle as well but don't go overboard. It made a noticeable difference on mine - even though performance was quite good compared to other 3.9s to start with. Even after the tweaking, my engine hardly smokes - even under hard acceleration.

(3) If the above are not enough, fit a turbo. I will be fitting one to mine soon, and plenty of others have done so and can give you tips. A 30% increase in power and a similar increase in torque is fairly easy to achieve.

[abaddonxi]

This might be the silliest suggestion, but have you thought about the LPG injection system?

http://www.dieselgas.com.au/home.htm

They talk about 10-30% performance boost, and you get the government to pay for half of it.

It would also probably be a lot easier to plumb than a turbo.

Cheers
Simon

[Nathan]

This might be the silliest suggestion, but have you thought about the LPG injection system?

http://www.dieselgas.com.au/home.htm

They talk about 10-30% performance boost, and you get the government to pay for half of it.

It would also probably be a lot easier to plumb than a turbo.

Cheers
Simon


From what I hear the best diesel/gas performance boost comes when you have a turbo AND LPG.

Nathan

[97discotdi]

The lpg does work better on turbo engines, as the introduction of the lpg requires more air to burn it. I have upped my boost by 2psi at the manifold.:angel:

[EchiDna]

well mine is a 4BD1T, but not having driven a NA 4BD1 I can't advise the difference... the turbo lag is... well.... er....um.... a long period of time to say the least, but then I'm tempted to intercool it as well - this should ensure an even longer time to kick in *sigh* a big fat exhaust will also help....

BLKnight is probably your best bet here as he deals with (and I assume drives) both motors regularly...

[justinc]

Ok Mr_sav,

Here is some info for you, I hope I don't confuse the issue....

When I bought my 4BD1 and installed it in my RR, it was ex 1988 110 and non turboed. It had about 390,000km on it, and was in excellent condition due to a religious service history. I immediately turboed and intercooled it, increased the fuelling and fitted a 2.5" free flowing exhaust.
I cannot comment on its standard performance because I hadn't driven it prior, but I have numerous NA 110's as customers and turbo ones too, and there is a huge improvement. I haven't dyno'd mine as I don't really want to see my Garrett turbo housing glowing orange just for the sake of a bit of paper, but I may in the future out of interest.

With equivalent gearing to an early 4 spd 110, and 255/85/16 BFG Mudders (33") fitted today:D,and sensible fuelling I get a max EGT of 520degC , and will hit the fuel governor at 130kmh in top gear easily. On a fuel consumption note, I get between 25 and 27 mpg without a worry, and I would ESTIMATE that I have about 30 to 40% more torque (a little lower down aswell) than standard. And very little smoke even though my injectors haven't been serviced yet. Ever.

With this fuel setting I get good economy, BUT I have had 650degC on the pyro with more fuel and boost, chirped the tyres and broken auto trans sprags with this engine in the past...

The use of piston oil jets and the like that is found in the factory turbo version is not really necessary in this application, as these engines are designed for a duty cycle on full boost ina truck with far more weight than a 110 is ever likely to drag along...And they will last 1,000,000km in a truck!!!

I would definately urge you to turbo it and you won't be disappointed.
You can Email me or call (03) 6229 1102 BH if you like for more raving and praise about these engines....:o:D

JC

[County3.9]

(1) Check/Adjust timing - 10deg. BTDC is right I recall. Over time the pump timing will retard slightly as everything wears. Advanced timing usually gives better performance (but don't go too far as this won't help EGTs).

(2) Fuelling can be increased on an NA vehicle as well but don't go overboard. It made a noticeable difference on mine - even though performance was quite good compared to other 3.9s to start with. Even after the tweaking, my engine hardly smokes - even under hard acceleration.

(3) If the above are not enough, fit a turbo. I will be fitting one to mine soon, and plenty of others have done so and can give you tips. A 30% increase in power and a similar increase in torque is fairly easy to achieve.

Ben,
Can I fiddle with this myself or do you recomend getting it done by someone who has a clue???
Col

[mr_sav]

Cheers, Justinc

I appreciate your time and Info, along with the others.

Regards.

Steve.

[isuzurover]

Ben,
Can I fiddle with this myself or do you recomend getting it done by someone who has a clue???
Col

Anyone who can use a spanner (competently) can time a 4BD1 and adjust the fuelling. I re-timed a (OZ Built) 110 county in the middle of nowhere in Guatemala using only the tools we had with us!!! So it is definitely a DIY job ;)

If adjusting the fuelling yourself, only make very small adjustments at a time, and take it for a drive in between each adjustment - and also get someone to watch how much smoke (if any) is emitted on full acceleration.


EDIT - Justin - Your rangie sounds like a beast - any pics? Will be interesting to see how much extra power I can wring out of my 110... We will have to have a race across the nullabor when mine is finished. :o ;) :)

[jakeslouw]

I don't wanna hijack this thread, BUT......

I just can't seem to find any intelligent, free source for sizing an air-to-air intercooler.

And before you all say "biggest is better", it is NOT: in fact, if you go too big, the pressure drop caused by air resistance in the IC causes a DROP in performance. Go read up on this.

So again:
if I have the proverbial Turbo Diesel, let's say a 3.9 Isuzu 4B1DT for instance, how big is the smallest and/or optimum size for an IC?

A 6 liter TD motor runs a 100cm x 64cm x 6.cm core. That's obviously a truck engine, and like our TD motors, built for sustained power output.

A typical after-market core size would be 60x30x7,5cm (24 x 12 x 3 inches for you bloody Imperialists....:p)

But what is good for a 3.9 Isuzu?

OK, let's get to airflow:

3900cc x 66 revs per sec / 4 cylinders = 3.9 cubic meters per min. (3900cc = 3.9L, 1000L = 1 cubic meter)
That is equal to 3.9 x 35.3 = 137.7 Cubic Feet per Minute.
(Conversion tables Cubic metres to cubic feet (http://convert.web-max.ca/index.php'select=16))

(Can somebody just verify my maths?)

So we can say our Isuzu at peak revs will be able to flow about 140 CFM.

Some sites state a "rule of thumb" of HP x 1.5 = target CFM.

So if our CALCULATED CFM is 140, then our ball-park HP on the Isuzu would be around 93HP.
Does that sound right for a stock 4B1DT?

OK, so now we want to run a full 1 BAR: that implies a 2 x compression.
So that means our IC must flow a minimum of 280CFM.

Now 280CFM is small bananas when it comes to ICs.

Can we then say that Garrett's web site is correct, and their smallest IC is OK?
TurboByGarrett.com - Catalog (http://www.turbobygarrett.com/turbobygarrett/catelog/Intercoolers/Intercoolers.htm)


Part Number

Hot Flow
Length (in)

No Flow
Height (in)

Cold Flow
Width (in)

Core Weight
(lbs.)

* Horsepower

Type

703521-6001

6.0

12.0

4.5

9.0

180

BP

So a 6x12x4.5 inch IC will do the trick?

Bell Intercoolers say 283 CFM is possible from a 4.2 x 6 x 3.5 inch core:

Bell Intercoolers | Air to Air Intercooler Cores (http://www.bellintercoolers.com/pages/aachart350.html)

But then I found this:
Horsepower (hp) = 0.533 * intercooler volume (cubic inches) + 50.17
So if we want to run 150HP from our 3.9, here's what happens:

150 = 0.5333 x IC Vol +50.17

that means, by substitution:

IC Vol = (150 - 50.17) / 0.533
= 187.3 CFM

So a 280CFM plus IC will work just fine.

An IC that can flow that amount of air is around 12 x 5 x 3 inches (3 inches being the standard core thickness). So 12" x 5" is L x H.

Any combination that totals 60 square inches x 3 inch thick will do the job:
- 5 x 12
- 4 x 15
- 3 x 20
- 6 x 10

In fact, that gives an internal area of 60 x 3 = 180 cubic inches. Hmmmm.

Garret = 6 x 12 x 4.5 = 324 (that's pretty big, but fits the numbers for 180HP)
Bell = 4.2 x 6 x 3.5 = 26.67 (that doesn't look right, does it?)

Then I found this:

Internal Flow Area (in3) = https://www.aulro.com/afvb/images/imported/2010/08/882.jpg


So:

Internal flow = 6 x (150) / 100
= 9 in cubed

So then the Bell figures son't look too shabby.

Now I'm just confused.

[Dougal]

A bigger intercooler has less pressure drop.

A turbo intercooled 4BD1T with 15psi boost at 3000rpm will suck about 300 cft/m.
At that point you're pushing approx 130kw with safe EGT's.

[jakeslouw]

Thanks Dougal.

So my only mistake was under-estimating the power output on the 4BD1T.

OK, so we take a 2.7 non-intercooled TD motor that currently pumps 100HP:

If I add a 6 x 12 x 4.5 inch IC, and we assume 70% volumetric efficiency, can I say that I will get a 30% increase in power without significant fuel pump adjustment?

[Dougal]

Thanks Dougal.

So my only mistake was under-estimating the power output on the 4BD1T.

OK, so we take a 2.7 non-intercooled TD motor that currently pumps 100HP:

If I add a 6 x 12 x 4.5 inch IC, and we assume 70% volumetric efficiency, can I say that I will get a 30% increase in power without significant fuel pump adjustment?

I don't think you'll get any meaningful power increase without a fuel increase. You'll get a little extra, but it's not going to be worth writing home about. The intercooler is just there to cool the boost down so more fits in each cylinder. The power still has to come from burning fuel.
The TD27's can't be running much boost stock, so an intercooler will have limited benefit. At 12psi an intercooler is optional, once you're past 15psi an intercooler is a very good idea.

Honestly, I don't see the downside to a huge intercooler. Throw in the biggest one you can fit.