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Intercooler question

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Old Dec 21, 2007 | 12:23 PM
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Question Intercooler question

I bought myself a 13BT series 4 engine for my VW bug conversion and have a noob question regarding the intercooler.
I understand that the intercooler cools down the compressed air coming from the turbo before it enters the engine thus making it denser and thus increasing the amount of fuel that can be burned in the combustion cycle.

However I'm looking at the intercooler sitting on top of the engine and I can't figure out how it actually cools anything without any air passing through the fins.
Is there a fan or something on the RX-7 that forces air through the intercooler?
If not then how does a "radiator" with static air sitting between the fins actually cool anything?

Thanks
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Old Dec 21, 2007 | 12:28 PM
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The air still goes through. The bottom plate on the IC doesn't seal the IC. At higher speeds the hood opening allows air to be shoved in. What car is this motor going into?
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Old Dec 21, 2007 | 12:50 PM
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he is asking "how does the intercooler cool the air going through it when there is no outside air passing over or thru the intercooler?" like in the back end of an older VW Bug.
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Old Dec 21, 2007 | 12:55 PM
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Originally Posted by phoenix7
The air still goes through. The bottom plate on the IC doesn't seal the IC. At higher speeds the hood opening allows air to be shoved in.
Hmmm ... so it basically has little to no effect at low vehicle speeds.

What car is this motor going into?
It's going into a 1974 VW Beetle which means that no air will be forced through it.
I'll have to make a plan to get some air flowing through the fins and then maybe use a water based intercooler later.
Thanks for the reply.
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Old Dec 21, 2007 | 01:02 PM
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your turbo shouldn't be pushing hot air when it's not boosting. Boosting = higher speeds = hotter temps.

https://www.rx7club.com/showthread.p...ight=Bug+turbo
https://www.rx7club.com/showthread.p...ight=Bug+turbo
https://www.rx7club.com/showthread.p...ight=turbo+bug
https://www.rx7club.com/showthread.p...ight=turbo+bug
https://www.rx7club.com/showthread.p...ight=turbo+bug

Searched the forum for turbo bug. Find out how the turbo bug guys are mounting their things.

Last edited by phoenix7; Dec 21, 2007 at 01:09 PM.
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Old Dec 21, 2007 | 01:20 PM
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I always wondered about those air cooled VWs. I'm sure you can get an aftermarket custom unit to work. Myabe mounting it parallel to the ground with it's own air supply from under the car or something. Kinda like the oil cooler setups Mazda Competion used that I'm always talking about.
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Old Dec 21, 2007 | 01:31 PM
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I removed my intercooler in preperation for replacing it with water/alcohol injection after seeing a thread in the AI section of the forum. I have been lightly driving the car around dataloging (haltech e8) and have come to the conclusion that an intercooler isn't needed on stock turbo cars running 8psi boost or less. I am using stock 13b-rew twin turbos, currently non seq, (no boost controller, wastegate control only) and after sustaining 8 psi for 30 seconds the intake temps never climb above 40 degrees over the ambiant temp.

The ambient temp at the time was 65 deg F and the max temp was a little over 100 F. As read from the haltech temp sensor.

8 psi is well within the efficiency range of the turbo, so I'm sure it will get much hotter with more boost, but perhaps you should consider water/alcohol injection instead of an intercooler. It can be done for nicely for less money, and there is the added bonus of a much better throotle response and slightly faster spool.
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Old Dec 21, 2007 | 02:04 PM
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i would custom an intercooler setup. im not sure how much space you have but if i were you id build a duct from the bottom of the car and use a fan to suck air and blow it through the core. can you post some pictures, these projects are always fun to look at.
good luck
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Old Dec 21, 2007 | 03:05 PM
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there is a guy with a 13B-T porsche 911. I'm sure he had the same issues with his car. I don't know his name so you'll have to search.
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Old Dec 21, 2007 | 04:03 PM
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just make an intake system like mr2's and nsx's
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Old Dec 21, 2007 | 04:06 PM
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old bug with rotary turbo having fun!! sick bug!!


Last edited by phoenix7; Dec 21, 2007 at 04:11 PM.
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Old Dec 21, 2007 | 07:21 PM
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Originally Posted by Surge
Hmmm ... so it basically has little to no effect at low vehicle speeds.
No air-to-air intercooler will, no matter where it's located.

It's going into a 1974 VW Beetle which means that no air will be forced through it.
I'll have to make a plan to get some air flowing through the fins and then maybe use a water based intercooler later.
I would concentrate on that now instead of wasting time with a stock IC. If aftermarket W/A intercoolers are out of your budget, you could jacket the stock IC like this. There's lots of interesting info on custom and DIY W/A systems all over the internet.
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Old Dec 21, 2007 | 07:54 PM
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i remember that thread. I wanna say 88integraLS but that's just a wild *** guess.

Just search for it
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Old Dec 21, 2007 | 08:06 PM
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id imagine you would need an intake scoop like you see on Mister Two's
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Old Dec 21, 2007 | 08:08 PM
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pics or ban.
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