Which Intercooler? Recommendations

[madkel]

Ok, time to make the investment to keep the 1993 K2500 pulling strong. The heavier trailer is taking a toll when climbing the grades. Here are the specs of the truck:

1993 K2500 Ex Cab. 165K. 4.10 gears. NV4500. New IP(+10%). Upgrades = 3" exhaust turbo back. Crossover pipe. K&N. Snorkel gone. Turbo boost lever,
285-75-16s. 180 T stat. Gages.

In the past the boost gage went to 10 -12 PSI when running empty, but then it was time to shift so the boost dropped.

Now with the bigger trailer when climbing the grade to the desert the pressure goes to almost 15 PSI and then the EGTs climb to 950F (post turbo in the elbow). Then I down shift and at 2500 rpm the boost is still is going to 15 PSI. I know that this is too hot for the engine so I want to cool the intake down with an intercooler.

My question to all who read this is:

Which intercooler is the best to buy?

I am leaning towards a kit rather than putting one together myself. I think it will be easier to install. I am not the most technical guy out there, but I did install the entire power-up kit (Exhaust, Gauges boost lever) in my driveway. I know there was an article published on the Page about a $400 DIY intercooler kit so if that is easy and the best way to go, then I will do that, but I am looking for input.

One last thing, I have a tow hitch on the front of the truck (To push the trailer around). It looks like there will be enough room to fit an intercooler there, and the hitch will provide a little bit of protection also so if you have an intercooler and know the size of it if you can pass it along that would be great also.

Many thanks

[Billman]

Most people have been fabricating their own set-up with an intercooler that fits where they want to put it, then put together piping to plumb it. Mainly because they don't want to pay the price or put it where it was designed to mount. The downside, in my opinion is not the neatest install. Pipes begin to make there way through fenderwells near tires. Rarely will you see a neat, clean install.

I'm no Professional Engineer or Fabricator, but I have done my share of Custom Projects. Fabricating an Intercooler set-up was not something I wanted to tackle. Didn't have the time or the ambition. Most importantly, I couldn't Fab a nicer set-up than the one I purchased.

If you can fit & afford it, the Kennedy/Spearco has worked nothing but flawless for me for 5 years...

[Slim shady]

Do a search on the forum and you will find a lot of variations on what you are asking about.

Here is a link to the pictures of my set-up: it has three inch piping. I think it is as professional as any of the kits offered. The whole thing cost less than $400.00 including my time.

http://www.thedieselpageforums.com/photopost/showgallery.php?cat=2

There are others that look as well as some of the kits out there. :cool:

[DennisG01]

I recently bought the Kennedy kit for some of the reasons you mentioned. I feel capable of making my own, but when it comes down to it, I really didn't want the hassle. This is a tried and true kit - it works and works well.

[DA BIG ONE]

Consider, a unit that flows 650+cfm and match to your existing intake size bigger pipes w/o more flow will cause more even too much pressure loss across IC.

[DmaxMaverick]

Actually, pressure loss is a good thing (as long as we aren't talking about a leak). More pressure loss is more dense, cooler air. That's why we want an IC. If you reach a point the loss is great enough to drop power, it's the turbo that isn't keeping up or the IC us underrated. Once spooled, the turbo will fill the void in a hurry (milliseconds). The lag off idle (or off no-load) can be slightly greater, but once spooled, it's insignificant. The greater pressure drop allows for a greater amount of dense air at the plenum. The more dense and lower pressure air means more O2 available for combustion. If the IC flow rating and heat transfer ability is above your needs, the pressure drop is not an issue, but a benefit. Higher pressure at the plenum is not necessarily a good thing if the O2 content is low, such as with hot air w/o an IC. Lower pressure air that is cooler and more dense is the reason we install IC's in the first place, which allows more fuel to be burned (more power), and lower pressure is less stress on the engine (also a reason for lowering the CR).

[Slim shady]

Consider, a unit that flows 650+cfm and match to your existing intake size bigger pipes w/o more flow will cause more even too much pressure loss across IC.

Actually to expand on the previous post if I had wanted to make the system even more efficient in theory I would have used 2.5 inch pipe to the inter cooler and then went to three inch after the inter cooler.

The physics behind it are similar to air conditioning. When a compressed gas expands it sheds heat. Similar to compressing gas which produces heat, so three inch is better in that respect and three inch flows more air than a 2 and a half inch pipe, the turbo can match the pipe size with no problem.

All of the above events happens in milliseconds so there is no lag from using three inch pipe over 2.5 inch pipe.

Using my inter cooler I usually ran no more than ten degrees max over ambient temp even in the summer.

Now with a turbo that flows more air than the GM -* and more efficiently I have ambient air temps most of the time and under 14 to 15 psi boost I don't see more than ambient temps on the cool side of the inter cooler except in 90 to 100 degree days. So works WELLLL , manufactured kits came from someone's innovative idea and that innovative idea was only one of many ways to address the same problem.

[DmaxMaverick]

Realistically, or in theory, it won't work that way. The heat shed would have been created somewhere. In the case of your scenario, that heat would have been generated by the restriction prior to the expansion, so it's counterproductive. In the case of an A/C system, the heat shed at the evaporator restriction (orifice or expansion valve) was created by the compressor, which, in turn, created pressure via the restriction of the orifice or valve. Take away one, and you lose the other. Using a restriction (for the purpose of heat loss during expansion) in a turbo/IC system would be counterproductive. You'd be creating heat via compressor outlet restriction, only to shed it later at the expansion. While all this is going on, additional heat is created because of all the friction happening in the system, from the air itself and mechanical components having more load on them due to the additional restriction. The end result is more heat, and more airway load, which translates to more engine load (less power). In the case of an A/C system, the purpose is to remove heat from one place to dump it in another place (cab to outside). The IC would be removing heat from the outside, and dumping it to the outside, which only adds a complicated process with no gain. The IC will transfer heat to ambient air, after that heat was created elsewhere. Picking something up only to put it back where you got it takes energy, with no return.

For the purpose of function, an IC system would be more effective with larger inlet and smaller outlet plumbing. Hot, less dense air occupies more volume than cooler more dense air. That means there should be a need for more volume prior to the IC core than after.

[Slim shady]

I meant that already heated air from the turbo going into an expanded chamber or pipe in theory will shed heat. (pressure differential) Air density wasn't part of it. I know it is relevant to the whole picture, but temp differentials and air density where not what I was trying to explain.

Expanding gas absorbs heat, compressing gas generates heat,

I may not have been or still have not explained what I mean clearly.

[DmaxMaverick]

I understand what you are saying, and the theory is correct. Problem is, you don't get anything for free, and in this case, the cost is energy. The cooled gas (air) entering the expansion chamber would have to be restricted/compressed again before hitting the intake runners, negating any cooling gain from the expansion. The only cooling advantage possible would be the surface area of the expansion chamber, provided the delta T of the internal vs. external is beneficial. If it is under the hood, it's likely to soak more heat than shed.

[Slim shady]

I see your point: the air would be re compressed again on the intake side after the inter cooler negating any net gain.

Still if you measure pressure and temp at the compressor outlet it would be greater in temperature and pressure, than the engine intake at a lower temperature and pressure. the drop in pressure and energy exchange being across the inter cooler.

Though it wouldn't be enough to measure or make a difference, not really relevant in this application. Point taken