Innercoolers are for race boats.

What determines the need for an innercooler? Reduction of intake air temps...I know that is one reason.

How about climate? All else being equal (same engine/boat) is a person more likely to need an innercooler in let's say Florida vs Michigan?

What are the other reasons if any and why?

The intercooler meerely cools down the intake charge going into the combustion chamber. Blowers compress air, and the intake charge is always under pressure. When the blower compresses the air, it creates heat, the more compression, the more heat. So, the more boost you run, the faster the blower has to spin, and the faster it spins, the more heat it generates. Now you're stuffing a hot air charge into the combustion chamber, which is already hot from engine running temps. The hotter the air charge that goes into the combustion chamber, the sooner it will ignite, that's called "preiginition" or as we all know "detonation".
Once detonation occurs, it will show up on the spark plugs first, there's little silvery specs on the plug tips, kinda like you misted it with some silver paint. Those little specs are from the piston starting to melt or dissolve. This is caused from a intake charge that is way too hot, and generally from too much boost.
With an intercooler, the air has to go through the intercooler first before it goes into the combustion chamber, thus cooling the air charge. The cooler will generally cool the air charge as much as 100-150 degrees in some cases. Therefore allowing you to run the same amount of boost without any detonation.
The smaller the blower, the harder, or should I say the "faster" it'll have to spin to let's say achieve 5 lbs. of boost. A 250 blower moves 250 cu. in. of air, a 871 moves about 425 inches just about the same as a 420 mega blower. A 10/71 moves close to 500 cu. inches of air, and is the largest blower you can run without an intercooler and still have clearance to remove your distributor without taking off the blower. So, a 10/71 will have to spin at almost half the speed as a 250 blower to achieve the same amount of boost, therefore, creating way less heat while doing it. So, you'll need to use an intercooler with a 250 if you want to make any kind of boost, way before you'll need to use one with the 10/71.
Do you need to use an intercooler??? Absolutely not, you just can't exceed a certain amount of cylinder temp while you're under boost conditions. That's why it's best to run the engine on the dyno, and then you'll have all the data of what you can, and what you can't do with it as far as boost goes amongst many other things.

The bigger blower will allow you to make more HP safely without adding an intercooler, by creating a cooler air charge into the engine, from it spinning slower. Remember, the bigger the blower the slower it has to spin to move the same amount of air. Now, does anyone still think the smaller blowers are still better??? :grinser010:

Great explanation Frank, totally makes sense.


I have the small 177 blowers. So If I was running 5lbs of boost, and went to a 250 blower, basically it would be like installing a intercooler on my 177? Cooler intake charge(if I was running same 5 lbs of boost on the 250?

When air and gas vapor are hot, they expand taking up more space in the piston. The intercooler condenses the air/gas vapors which allow more to get packed into each piston; which means more power. Engines always run better when they are cooler because of the condensing of air/gas vapor.

The only time I would not run an intercooler is because of height clearance. Cost would be a stupid reason not to get an intercooler because you have a much getter chance of blowing up the motor without one.

Thats the spirit ! ! :cool:
You do know he holds 260 gallons, right ?
It aint no Fountain holding a measly 140 or so gallons ! :drool: :D

I'm gonna buy stock in BP just so I can kinda pay myself back ! :crazy:

"It aint no Fountain holding a measly 140 or so gallons ! "

220 here...

You say "measly"?

Its Club Fountain where you keep that Gun no? Remember, your just a guest member there.:p

I think 38 and smaller Fountains all have small fuel capacity, the older ones anyway.

And ya, lots of Fountains in the warehouse, Scott Shogren is doing a great job !

Just pullin your chain...

hammer save your card for me, i know your not afraid to fill it up. Ill give ya a redbull and goose