Turbo Charged 4.0L BII Build

[nate12346]

Well I have some bad bad news....
I was crawling around in a empty house lot last weekend and rolled my truck!...
Mechanically it is perfect. I busted out all the windows except the front windshield and driver side window. With a bunch of body damage. The roof held up a lot better than i thought.

So my Christmas break is going to consist of chopping my top and replacing doors/fenders...... instead of finishing the turbo

 

[RacinNdrummin]

An intercooler is used to stop detonation. It nets you no power. A 5-psi system with an intercooler will produce the same power as a 5-psi system without an intercooler. Now, if you wanted to dial up to 10-psi and experienced detonation, you'd install an intercooler. The intercooler would keep the air being forced into the cylinder cool, and therefore decrease the likelyhood of early detonation.

Cooling the air between the turbo and the engine still yields the same amount of air.

From Superchargersonline: "Essentially, run an intercooler when only when running peak boost (i.e. any more boost would cause detonation) for the octane of fuel you use."

This is just simply wrong.

5-psi of boost at 300* is far less air than 5-psi at 100*.

Less air= Less fuel= Less power.

So even at 5-psi, an intercooler will make more power on any given engine.

And regardless of how restrictive the IC is, if your WG is referenced at the intake, and your getting the boost levels your after at the intake, it doesnt matter how restrictive the IC is, what you need to be concerned about is IC efficiency, and how much it can lower your intake temp.

 

[turbo cat]

depending on the setup you IATs woulnt be that high on only 5 psi. This is why a intercooler isnt truly necesary. The other issue is a intercooler will slow response depending on how restrictive the intercooler is (theres many different designs. cooler air does=denser air. It all depends on how badly the compressor is heating the air charge. Another method of intercooling can be running E85 which has abotu a 105 octane and has intercooling abilities.

 

[Evan]

5-psi of boost at 300* is far less air than 5-psi at 100*.

Less air= Less fuel= Less power.

I get that. You're missing the point.

 

[RacinNdrummin]

How am I missing the point? Your obviously missing the point and have no idea how turbocharging works.

I just explained it as bare bones as can be.

5psi non-intercooled air, is less air, than 5psi intercooled air.

Less Air= Less Power.

Now, how much less is the real question, but I gaurantee it will be less.

 

[88ranger2.95sp]

5psi non-intercooled air, is less air, than 5psi intercooled air.

Umm.. since when does the intercooler add air to the system? Does a radiator add coolant to the system? Capacity, but not pressure.

Rob

 

[turbo cat]

It dosent add air the air is denser. Coolar air =denser air. The collder the Air charge more power can be built from the same amount of pressure. it often depends on the compressor/turbocharger design on how much the compressing will heat the air charge. On cold days my 4.0 comsumin 5 psi is just fine but on 90+ degree days it does get heat soaked and performance falls off a little. If the IAts are too high it can also cause detonation and elevated EGTs. There are also other meotods of intercooling like meth injecton and E85 can be used as a intercooling agent. The fuel has high octance and is cold to the touch.

 

[RacinNdrummin]

Umm.. since when does the intercooler add air to the system? Does a radiator add coolant to the system? Capacity, but not pressure.

Rob

When you cool air, it makes the air more dense. How do you make air more dense (i.e. Volume stays the same, but mass increases) without adding more air? You are packing more air molecules into the same amount of space.

Water is a liquid and cant be compressed, like a gas, therefore your radiator analogy is wrong. Plus liquids arent as sensitive to temp changes as gases are.

 

[RacinNdrummin]

It dosent add air the air is denser. Coolar air =denser air. The collder the Air charge more power can be built from the same amount of pressure. it often depends on the compressor/turbocharger design on how much the compressing will heat the air charge. On cold days my 4.0 comsumin 5 psi is just fine but on 90+ degree days it does get heat soaked and performance falls off a little. If the IAts are too high it can also cause detonation and elevated EGTs. There are also other meotods of intercooling like meth injecton and E85 can be used as a intercooling agent. The fuel has high octance and is cold to the touch.

Yes but even E85 and other fuels with low evaporation temps can benefit from intercooling even further.

And yes you are right it does have a lot to do with compressor efficiency, but it also has a lot with how well your compressor is matched with the pumping characteristics of the engine as well.

 

[turbo cat]

From wikapedia

An intercooler, or charge air cooler, is an air-to-air or air-to-liquid heat exchange device used on turbocharged and supercharged (forced induction) internal combustion engines to improve their volumetric efficiency by increasing intake air charge density through isochoric cooling. A decrease in air intake temperature provides a denser intake charge to the engine and allows more air and fuel to be combusted per engine cycle, increasing the output of the engine.

 

[turbo cat]

An intercooler, or charge air cooler, is an air-to-air or air-to-liquid heat exchange device used on turbocharged and supercharged (forced induction) internal combustion engines to improve their volumetric efficiency by increasing intake air charge density through isochoric cooling. A decrease in air intake temperature provides a denser intake charge to the engine and allows more air and fuel to be combusted per engine cycle, increasing the output of the engine.



Now heres the deal as air heats up it expands (thermal expansion) and it cools down the molecules pack together (denser air).

 

[RacinNdrummin]

From wikapedia

An intercooler, or charge air cooler, is an air-to-air or air-to-liquid heat exchange device used on turbocharged and supercharged (forced induction) internal combustion engines to improve their volumetric efficiency by increasing intake air charge density through isochoric cooling. A decrease in air intake temperature provides a denser intake charge to the engine and allows more air and fuel to be combusted per engine cycle, increasing the output of the engine.

More air......

Yup...

Even though I wouldnt quote dikapedia for crap.

 

[RacinNdrummin]

...



Now heres the deal as air heats up it expands (thermal expansion) and it cools down the molecules pack together (denser air).

But you have the same volume, therefore, a denser charge means more air.

 

[Digital Squirrel]

I relies I have no credit yet on this site as this is my second post but turbo cat is right. Now I also think at such a low psi that unless you live south of the equator it’s not worth the money for an air-to-air intercooler. You just wont see that much of an improvement but, you will see one! Now if your going to up the boost some time, live south of the equator or get a water to air intercooler I’d say you will see a big differents. Now if you just want a quick boot on a hot day every so often I would get a nitrous bottle with a hand spray attachment and hit the intake manifold when needed. Cheep and easy!

 

[RacinNdrummin]

Dont matter if your north or south of the equator dude, same principle. And the argument wasnt based upon whether it was worth it or not, it was if it works or not, and you agree with me not him, well maybe him as well...

 

[Digital Squirrel]

Dont matter if your north or south of the equator dude, same principle. And the argument wasnt based upon whether it was worth it or not, it was if it works or not, and you agree with me not him, well maybe him as well...

Ahh sorry didn't read the entire thread... then yes it will work.:icon_rofl:

 

[BlackBII]

Density = mass per unit of volume...so If the 'air' is more dense, then it has more mass for that given amount of volume.

And adding a charge cooler will always help.

 

[turbo cat]

it can help but also wit hthe bigger volume and restriction of the intercooler the response time is slower. But yes it will always air that is blown by densifying the air cahrge which means more air molecules per volume. its a balancing act. if your only pushing 5 psi of boost and depending on the blower design, it may only heat the IAT by only small increase in temps. Then if you add an intercooler you can still gain but the loss of response may outweigh the loss of power with the warmer air charger

 

[CopyKat]

Well I have some bad bad news....
I was crawling around in a empty house lot last weekend and rolled my truck!...
Mechanically it is perfect. I busted out all the windows except the front windshield and driver side window. With a bunch of body damage. The roof held up a lot better than i thought.

So my Christmas break is going to consist of chopping my top and replacing doors/fenders...... instead of finishing the turbo

Since your putting it on hold I'll continue this project.......:icon_thumby:

 

[RacinNdrummin]

Density = mass per unit of volume...so If the 'air' is more dense, then it has more mass for that given amount of volume.

And adding a charge cooler will always help.

Exactly.

When you add more mass, you are adding more of something.

Adding more air mass, is adding more air, period.

it can help but also wit hthe bigger volume and restriction of the intercooler the response time is slower. But yes it will always air that is blown by densifying the air cahrge which means more air molecules per volume. its a balancing act. if your only pushing 5 psi of boost and depending on the blower design, it may only heat the IAT by only small increase in temps. Then if you add an intercooler you can still gain but the loss of response may outweigh the loss of power with the warmer air charger

If anything more volume in a boosted application is better, and the increase in spool-up time is unnoticeable. If it was such a problem, rear mount turbos would take forevvvvvvvvvver to spool up and create boost, and they dont.

The only time an intercooler becomes a problem is when it is a highly restrictive design, like a volvo FMIC or something of that sort, and those really arent that thermally efficient anyway. With that being said, Id still take a volvo IC over no IC, even at 5psi.

In a boosted application you want the charge air to be as close to if not lower than the ambient temp.

Sometimes its easier to not have an intercooler, such as in an explorer with limited space and piping concerns, but your still not going to make the same amount of power, let alone have the timing capability, of an intercooled setup.