Plan to build twin turbo SBC found a intercooler originally for a Dodge 3/4 ton with Cummins. I should be able to make it fit somewhere on my 86 C10. My question is could it be too large, effecting my boost fluency?

 

bigger would have better flow and more cooling surface area ,,, not sure if a factory cummins ic would flow enough though, you would be using a lower pressure, higher volume than a 5.9l cummins

 

Only looking to push between 8-12 psi wanting a streetable setup. I guess I need to see about the flow capability, the bonus is the old ic is FREE.

 

People make 1000hp with the stock Cummins CAC. I don't see how it wouldn't provide the flow you'd need.

 

On a typical V8 equipped street car, you'll run into packaging problems long before you make the intercooler large enough to create engine problems.

 

On a diesel truck yes , on a 8 psi street car it will never flow enough to get close to that . More boost = more density. This is how you can get 1000 hp on a cummins loads of boost. Now when you look at the volume of air it doesn't change just the pressure. How much power will that cummins make if you limited the boost to 8 psi . On a v8 turning lot more rpm a second issue occur that being pressure drop after the cac meaning that to get more air in you end up with the turbo to cac boost is at 15 psi and the restriction vs the engine consumption leaves the manifold boost at 8 this is only for example purposes. You have a compressor that is generating heat at 15 psi and the cac is absorbing the heat and the 8 psi of air may not be any cooler than if you had just 8 psi and no cac at all .

 

To reply to this topic yes there is but like stated above you will run into a space issue before you get to the point of to much cac . If by chance you could get a cac to big it will only really cause lag on the bottom end and on off acceleration due to the large volume of the cac and the compressor having to pressurize a larger charge volume .

 

I don't understand on how a diesel application it'll flow enough air for a diesel spinning at 5500rpm but won't on a gasser? Are you saying that gassers require more air volume than a diesel?

 

No . The volume (amount of space or displacement )stays the same. A cummins at 5500 rpm has the same volume of air displaced at ambient pressure ( air around us as it is un boosted ) as it does at 100 psi . What is different is dinsity. 1 cfm of air at sea level has a dinsity of .0807 lbs . Now sea level pressure is 14.7 psi ambient so if you add 14.7 psi of boost your dinsity double. Now your 1cfm weigh .1614 lbs. Now 1lb of air can support rufly 1hp so you can see if a cummins at 100 psi of boost makes 1000 hp you divide your boost by adding 1 atmosphere (100 psi +14.7psi =114.7 ) by 1 atmosphere = pressure ratio (114.7/14.7 =7.8 ) so you dinsity is 7.8 times the .0807

 

That was an awesome explanation, thank you.

So the CAC from a diesel application is too much of a restriction for a gasser?

I'm feeling stupid not fully wrapping my head around this. I see tiny CAC's on cars with turbos all the tiny and it shocks me that they're even worth it at that size...

 

It's not just the width and hight but the depth of the core . Looking at it like a box of air . But if it's designed to work on a 5.9 it'll work with a gas engine of the same size and rpm just won't be able to make as much power due to less boost.

 

So for a gasser application we're really looking for something much less restrictive, something much more streamline? For lack of a better term...

 

It depends on the power goal and applications diesel cac can work good for gas application if you are looking for a mild 500 - 550 5.3-6.2 l engine to run at around 5000- 5500 rpm a 5.9 cummins cac would fit the bill. If you want more power and more rpm you should look for something like a 9400 international semi truck with a over under radiator cac configuration it's core is about 4 inch thick and ruff 30x 20 across .can be modified for inlet configuration to fit and come with 4 inch inlet outlet. There are also some freightliner application that are similar. Basically look for a cac that has the same atrubute as a performance aftermarket cac for your application. But is cheaper than a big name brand .

 

Wow this thread seen more activaty then I thought it would all good stuff. Another bonus I found the factory bracket support with rubber bushings is attached making mounting simple.
Thanks Everyone

 

One that some of the Turbo Buick guys use is the 7.3 intercooler from one ton trucks. I've got a trans cooler from the same vehicle in my V8 S10, it's HUGE,

 

If you can package it, use it.... without accurate cfm, temp, and pressure drop numbers its tough to say what it will support hp wise, but many are making 750-1k hp on a smaller Chinese core.

 

Thanks Rick forgot to mention trans cooler also attach to the inside of ic . Btw Rick seen your vega and s10 on youtube MrRickracer

 

Mnix that is exactly my thought seeing that huge ic on a stripped frame was pure gold.