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Discussion Starter #1
i have been looking into putting an aftercooler on the f banger. i have been looking at cheap aftercoolers on ebay. the question i have is- how big is big enough ? at this point in time i plan to stick with the std turbo. i have an egt gauge to fit. i plan on turning up the pump a bit. on one post here, 1 cfm to 1 hp was mentioned. is this the go ? the cooler i reckon will fit in the front easiest is 400x220x65mm. with 3" in/outlet. any suggestions ?
 

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The sizing depends on the heat power you need to dissipate.
CFM ratings by themselves aren't much use, you need to consider the temperature which is largely boost dependent along with the flow.

IMO throw in the biggest cooler you can find and fit. The cooler you can get the charge the better. You're not racing 1/4 miles are you?
 

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Discussion Starter #3 (Edited)
no 1/4 mile action. it does drag the odd trailer about the place though, does that count ?:rasta: in all seriousness, the bigger the better ? just looked at the phot of the grunman ones, and they seem to be roughly a 600x300x40 core. how well do they work ? i can buy one roughly this size on ebay relatively cheap.
 

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IMO throw in the biggest cooler you can find and fit. The cooler you can get the charge the better. You're not racing 1/4 miles are you?
Ditto. If it is too big, it will not fit :).
 

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Discussion Starter #6
well, to get extremely technical, i am after an aftercooler. if it is between the engine and turbo, it's an aftercooler. if it is between stages on a compound setup, it's an intercooler. intercooler seems the most popular term for either though. all that said, the plan is to buy a 500x300x76 'cooler from ebay. $280 aussie pesos.
 

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well, to get extremely technical, i am after an aftercooler. if it is between the engine and turbo, it's an aftercooler. if it is between stages on a compound setup, it's an intercooler. intercooler seems the most popular term for either though. all that said, the plan is to buy a 500x300x76 'cooler from ebay. $280 aussie pesos.
Intercooler is technically correct. You are cooling between the compression of the turbo and the compression of the pistons.
IMO aftercooler is the wrong terminology.

As far as I'm aware, cummins are the only people who refer to aftercoolers as water/air and intercoolers as air/air. Everyone else calls them intercoolers and adds a water/air or air/air note as necessary.
 

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Detroit refers to an air to air between turbo and blower as an intercooler. And a water cooled one between blower and block is an aftercooler.

It's quite fuzzy, I would call it what you want and note air or water.

Grigg
 

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i have been looking into putting an aftercooler on the f banger. i have been looking at cheap aftercoolers on ebay. the question i have is- how big is big enough ? at this point in time i plan to stick with the std turbo. i have an egt gauge to fit. i plan on turning up the pump a bit. on one post here, 1 cfm to 1 hp was mentioned. is this the go ? the cooler i reckon will fit in the front easiest is 400x220x65mm. with 3" in/outlet. any suggestions ?
Isn't there some consideration about tube size to prevent pressure drop between the compressor stage and the cylinders? I seem to remember something about that from several years ago.
 

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Discussion Starter #10
i had the impression it is a bit of a fine line between big enough cores for good flow, and slowing down the air a bit to cool it. dunno. just bought a 400x220x65 'cooler anyhow. we'll see how it works.
 

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I just ran this through my pipes and came up with something, probably irrelevant.

A fluid can't, or can't easily, be compressed: hydraulics. A gas can be compressed: pneumatics.

Seems if an intercooler is oversized it could induce compressor lag. As compressor speed suddenly increases from heat the column of air will compress somewhat until pressures stabilize.

Too small an intercooler would restrict airflow, but cause more immediate throttle response until the system ran out of breath.
 

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I just ran this through my pipes and came up with something, probably irrelevant.

A fluid can't, or can't easily, be compressed: hydraulics. A gas can be compressed: pneumatics.

Seems if an intercooler is oversized it could induce compressor lag. As compressor speed suddenly increases from heat the column of air will compress somewhat until pressures stabilize.

Too small an intercooler would restrict airflow, but cause more immediate throttle response until the system ran out of breath.
Jimmy,
Not really irrelevant, but even an intercooler such as a 7.3 Powerstroke IC, or something larger, wouldn't be too large for our applications. An IC would have to be so large that it could not be practically installed in our vehicles (something 4BT compatible) to cause any appreciable turbo lag. So, really the bigger the better in this case, if you can fit it in. Lots of cooling area, and large inlets and outlets will benefit performance.
Bob B.
 

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I just ran this through my pipes and came up with something, probably irrelevant.

A fluid can't, or can't easily, be compressed: hydraulics. A gas can be compressed: pneumatics.

Seems if an intercooler is oversized it could induce compressor lag. As compressor speed suddenly increases from heat the column of air will compress somewhat until pressures stabilize.

Too small an intercooler would restrict airflow, but cause more immediate throttle response until the system ran out of breath.
Many people worry a lot about turbo lag from a big intercooler, but few stop to think about it.
The intercooler and pipes are already full of air, to pressurise them to 15psi only requires 60% of the volume and most turbos will acheive that very quickly.
The number of very fast 1/4 mile cars running big intercoolers shows how small the effect really is.

I suspect many people confuse boost threshold with lag, they drive a car with a massive turbo and a big front mount intercooler and blame the intercooler for the time it takes the engine to rev enough to spool the turbo.
 

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Thanks, guys!
 
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