Installing Charge Air Cooler 8v92T

[Scott & Heather]

So, I scoured the thread on installing a CAC on our new 102C3's 8v92 turbo. I won't be doing this immediately but I'm slowly gathering the parts and knowledge needed. What all do I need besides the cooler itself, the plumbing, and the deflector? I know I need to pull the aftercooler out and plug the water ports. Cliff, you mentioned needing to replace the turbo. Is this necessary? What turbo would be a good replacement if this is necessary? I am wanting to gain a little power (coach runs like a banshee when it's cool outside) and keep engine temps cooler too. Cliff just gave me great advice on my first purchase lol:


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[bevans6]

here is a question I've been pondering - how do you size a CAC for a given engine?  I ask because I have a friend storing some stuff at my place and he has a brand new paired CAC and radiator from something - probably around a 150 hp generator engine - that I could probably get for free.  Do you size by HP, CFM, core size?

Brian

[Scott & Heather]

From what I understand Brian, it's mainly CFM. I'm no expert, but I know the 8V92 needs a lot of air...something like 1600 CFM for a CAC. 5" inlet tubes and at least 1600 CFM are recommended...again, I'm just regurgitating what I've learned and read, not my own experience. This will be my first time utilizing a CAC. But after feeling how my bus runs on cool air (50's) and feeling how it runs when it's hot out, I can tell you it's worth it. 

[luvrbus]

They size the CAC on the engines intake CFM at the highest HP,I have a friend in Tulsa that builds the CAC I think he built TomC's for Don Fairchild the 8v71 or 8v92 will need 1500 cfm+ 10% The more surface sq inches the better they work

[Scott & Heather]

Cliff, can I use my stock turbo?


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[luvrbus]

  No it has to be changed

[HB of CJ]

I was also told the bigger the better, if everything is in harmony and works well together.  Also I was told that under some conditions, the actual charge air cooler or air to air inter cooler will work well enough just by itself that large power increases are possible. HB

[Scott & Heather]

Which turbo does it need to work with? I guess I'm missing something. Smaller or larger?


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[daddyoften]

I'm thinking of doing the same thing. I have a 4107 with a 77' 8v71T and also have a intercooler from a Volvo loader that had a 9 liter engine in it. I'm fairly confidant the CFM will be close but I to am confused about why a different turbo is needed. Please explain.
Thank you,
Eric

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[luvrbus]

The A/R (air ratio) is different example the after cooler engine use a ratio of say .97 to 1.39 the CAC engines depending on the injectors are a 2.59 to a 2.95 A/R a lot of the time you just the change the hot housing.

You can get by with the smaller A/R turbo and notice the difference but the boost is going to be low,you need to make up for all the piping and CAC someplace and you do that with more pressure and volume

Daddyoften Donaldson has the cfm rating on engines on their site it takes the guess work out of play    

[TomC]

Yes the guy in Tulsa, OK made the custom CAC for me, as Cliff said. I told him the engine and the size. It came perfectly made. With the combination of the 7G75 injectors, bypass blower, 12.7 liter Series 60 turbo with waste gate, fuel modulator, when pulling the Grape Vine southbound, I went from 32mph to and easy 45mph with NO visible smoke coming out of the exhaust stack (the AMGeneral has a built in roof stack on the driver's side that I can see through my mirrors). Turboing with CAC really wakes up the 8V-71.
If I had rebuilt the engine to turbo specs, with 17:1 pistons, smaller port liners, changed the timing and cams, I could have run 7G80 injectors for 400hp and 1200lb/ft torque. With that setup with a CAC, I could see using 7G90 injectors and getting into 8V-92TA horsepower range. Good Luck, TomC