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IS this true???

 
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Dave  
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PostPosted: Wed Aug 08, 2001 1:50 am    Post subject: Reply with quote

I read some where that for every 10 degrees the air temp falls you gain 5hp. IS this true. Is this the idea of intercoolers???
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924RACR  



Joined: 29 Jul 2001
Posts: 8102
Location: Royal Oak, MI, USA

PostPosted: Wed Aug 08, 2001 2:03 am    Post subject: Reply with quote

I think it's more like 2%, not a fixed output. That's part of the idea behind intercoolers, the other half being to reduce the tendency for detonation.

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Dave  
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PostPosted: Thu Aug 09, 2001 2:22 am    Post subject: Reply with quote

So there would be a benifit from cold air induction?
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MAS  
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PostPosted: Thu Aug 09, 2001 2:23 am    Post subject: Reply with quote

Yes there would be.

-MAS
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Rick MacLaren  
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PostPosted: Thu Aug 09, 2001 2:46 am    Post subject: Reply with quote

If you can figure out how to get colder air into the system I think everyone would be interested in that...either for NA or turbo applications. You might try asking Ed Moore about that one...he rigged up a cold air system to his race car. It might save reinventing the wheel.
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AppleBit  



Joined: 16 Nov 2002
Posts: 1516
Location: Minneapolis, MN

PostPosted: Mon Aug 13, 2001 11:24 am    Post subject: Reply with quote

Look at my website... it takes cold air from outside the engine bay...

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larso  
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PostPosted: Tue Aug 14, 2001 8:56 am    Post subject: Reply with quote

Here is the formula for figuring it out, but even being the more accurate equation it is, bigger engines react worse to cold air than smaller engines. Bigger engines are way more sensitive because amount of air and fuel you are mixing is much greater. In short, the bigger the engine, (we are talkin NA here, since turbos run hotter and are different in many ways), the more the cold air will f!ck other things up in the process, especially with carbs because of the fuel getting balled up from condensation on the intake tubes, and causing blasts of way to rich mixtures when you open teh throttle butterfly all of a sudden. With smaller engines it is more beneficial, especially with short tubed carbs and Fuel injection. Likewise, with smaller engines, spark plugs and ignitions will not improve HP NEARLy as much as on a big engine.
Here is the formula, and we use degrees celsius or kalvin, not ferenheight, for you american d!ckweeds that are stuck in old times and sometimes get mixed up.

Getting on to the formula....

The square root of (Existing temp VS proposed temp) times current HP.

which is: square root of (ET over PT) times your current HP.

Bottom line is, smaller engines, colder air rules.

Now the 944s IMO have big engines for the amount of cylinders they have...were not talking about the overall engine size actually, its the amount each clinder is displacing that is important...on a v-12 ferrari they have small cyls, on a 2 litre 944 its fairly big. think about it, each cyl in a 944 2.5 litre is the same as a mustang 5 litre.

So on a 3 litre v-12 ferrari...compared to a 944 3 litre 4 cyl...well you get the idea, the ferrari is going to benefit more.

Race cars with bigger engines actaully heated up the air and fuel and manifolds to get better use of power FYI.


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Dave  
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PostPosted: Tue Aug 14, 2001 2:37 pm    Post subject: Reply with quote

What about making a RAM air system???? Would there be any benifit form that???
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Peter_in_AU  



Joined: 29 Jul 2001
Posts: 2740
Location: Sydney, Australia

PostPosted: Tue Aug 14, 2001 6:59 pm    Post subject: Reply with quote

for some hard evidence on a ram/quad body intake have a look at http://www.autospeed.com/A_0163/page1.html

The article is about mods to a 4cyl 2litre SOHC (sound familiar?) actually a Ford Pinto motor.

Anyway, they measured an extra 12kW (say 16hp) on the dyno by just adjusting the runner lengths on the throttle bodies.
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