Adding an intercooler to an old truck?

[MattyF]

Only if you up the boost on the turbo though.... I've Seen plenty of engines with big intercoolers fitted on dynos making less power because of faulty actuators or the owner scared of running more boost, theoretically you would get more lag = less power

[treequip]

 

the intercooler just means you can run more psi =boost on your turbo keeping the charge temps low so the engine does not prematurely detonate.

More turbo boost = more power.

Nope, most of that is wrong. Adding an intercooler wont mean you can run more PSI. The pressure the turbo makes is a function of its geometry, its a usually fixed constant. The intercooler simply means the air getting to the cylinders will be cooler (hence the name), dense air holds relatively more oxygen than warm air and more oxygen just means a cleaner burn, unless you start messing about with the pump. Don't do this if you don't want to be picking bits of con rod out of the gutter.

 

 

You can adjust the actuator to keep the waste gate to stay open longer adding more psi............

 

Closed, you want the waste gate to stay closed, open waste gates make for slow engines.

 

Again, you cant add pressure but tinkering with the waste gate may give turbo pressure for a second or two longer on lift but it is a second you don't actually need because you lifted.

 

The waste gate is there to regulate turbo pressure and primarily to relieve it when needed. An open waste gate is the nice whooshing sound performance cars make on throttle lift. When you lift, fuel stops and there is temporarily no need for all that nice cold air so the waste gate opens and "wastes" it to atmosphere, get back in the pedal and the gate closes and restores the max air flow. "Wasting" it stops the turbo blowing hoses off the air system.

[MattyF]

Aye that's what i mean keep the waste gate closed longer... been down the pub after a fishing session so wondering if any of that made sense... which it clearly does not ! I will argue though the Benefit of the intercooler is to keep the temps down so you can run more boost.

[Ferguson system]

+1 treequip.

 

Cold air = cleaner burn and more power.

[openspaceman]

You can add more fuel by playing around I have no idea how but with turbos the power is all in how much boost the engine can handle ,the intercooler just means you can run more psi =boost on your turbo keeping the charge temps low so the engine does not prematurely detonate..

 

Matty are you talking of spark ignition engines?

 

 

Detonation is when a premixed fuel air mixture spontaneously ignites before the flame front initiated by the spark reaches the unburnt mixture.

 

It's why for a given octane rating the cylinder pressure must be limited. So with a fixed compression ratio if you up the inlet manifold pressure to cram more air in the pressure at TDC becomes too high.

 

A diesel is different in that the fuel is injected into an already hot mass of air and the rise in pressure is controlled by the rate at which it is injected, this is why diesels run much higher compression ratios than SI engines and because the pressure from which you can expand (i.e. push the piston down) the gases is a direct relationship with power diesels are better at getting motion out of the expanding gases, with a couple of caveats one being that diesels never run at stoichiometric rations, and two because the combustion is slower some of the fuel is less effective as the volume above the piston is already increasing as the fuel enters. Both these last points are partially addressed by common rail and electronic injectors.

[Logit]

One thing to watch out for on an older vehicle is the radiator. If you plan to put the intercooler in front of the radiator, the intercooler will heat up the air going into the radiator. I added an intercooler and then had to put in a new radiator since the old radiator was clogged up and couldn't cool the engine down enough when heavy towing. The fuel pump was adjusted as part of the installation (more fuel). The biggest difference was a significant boost in low down torque and it made towing a lot easier. It didn't appear to use any more fuel when driving sensibly. This was on a 300TDI engine with approx 100K miles on the clock.

[TimberCutterDartmoor]

diesels never run at stoichiometric ratio's

 

Certainly not rich of it (Lambda 1).

[njm]

The old Iveco six diesels were a fairly robust engine , intercooler and fine tuning of the pump should give you a nice engine , personally i would not raise the boost on an engine with this mileage or your likely to end up with a runaway when the turbo spits its guts , caution also as too much fuel will also lead to a thermal runaway condition , seen plenty of high boost actuator rod bodges over the years , screwing the rod in until the waste gate only opens 2 mm is not the wisest of ideas .

[openspaceman]

Certainly not rich of it (Lambda 1).

 

You changed my ration to ratios but put in a grocer's apostrophe:001_rolleyes:

 

Yes there is always spare oxygen in the exhaust of a diesel but I wonder how much the excess air is reduced by higher (and constant) pressure injection via a common rail?

 

The original concept of a diesel was that combustion took place at constant pressure rather than the constant volume of a SI engine. Now with the variable air mass provided by the turbocharger and quicker combustion the volume-pressure diagram must have moved toward the constant volume.

 

A diesel still remains a source of black smoke if fuelling for maximum power because of the nature of the diffuse combustion of the fuel droplets. They burn in two stages, firstly the hydro carbon is stripped of its hydrogen and later the carbon particles are burned (or not if over fuelled).

 

Whereas a premixed petrol:air mix has all the oxygen necessary for the complete combustion of the hydrocarbon molecule intimately next to each other, hence the blue flame, if over rich some carbon particles glow in the heat, just like a candle flame.

 

The old bunsen burners in the chemistry lab were a good demonstration of varying between diffuse and premixed flames.

[TimberCutterDartmoor]

You changed my ration to ratios but put in a grocer's apostrophe:001_rolleyes:

 

Yes there is always spare oxygen in the exhaust of a diesel but I wonder how much the excess air is reduced by higher (and constant) pressure injection via a common rail?

 

The original concept of a diesel was that combustion took place at constant pressure rather than the constant volume of a SI engine. Now with the variable air mass provided by the turbocharger and quicker combustion the volume-pressure diagram must have moved toward the constant volume.

 

A diesel still remains a source of black smoke if fuelling for maximum power because of the nature of the diffuse combustion of the fuel droplets. They burn in two stages, firstly the hydro carbon is stripped of its hydrogen and later the carbon particles are burned (or not if over fuelled).

 

Whereas a premixed petrol:air mix has all the oxygen necessary for the complete combustion of the hydrocarbon molecule intimately next to each other, hence the blue flame, if over rich some carbon particles glow in the heat, just like a candle flame.

 

The old bunsen burners in the chemistry lab were a good demonstration of varying between diffuse and premixed flames.

 

You are right about constant volume (SI) vs constant pressure (CI). Pure adiabatic compression to serve the carnot cycle; that is what RD was concerned with. Akroyd Stuart was the sparkless ignition man.

 

However, the system of injection build up and subsequent multiple injections, somewhat irrespective of pressure (altho that is needed - the term is "injection hardness" - particularly in a DI) is designed to maintain that constant pressure, hence greater torque outputs without higher bmep. So no, greater oxygen density isn't designed purely to decrease flame propogation time and a reduced CR will permit this. The idea of higher Inj pressure is merely to reduce droplet size and therefore improve mixing.

 

Re SI having all the oxygen neccessary for a complete burn - not at all; they might have been pushing lean burn for years but probe a SI engine exhaust (vs a CI) and you'll observe considerably higher UHC and even ultrafines. CI PM derives from fuel ash content; C as a survivor from the fuel would be be termed UHC in the vapour phase, not PM phase. This is pre-aftertreatment of course.