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Old 05-16-2014, 12:45 PM   #6 (permalink)
EcoModding Lurker
Join Date: Apr 2014
Location: Central OK
Posts: 24

Slow Silver - '09 Chevy Cobalt XFE Coupe
90 day: 37.56 mpg (US)

GMC pickup - '86 GMC C1500

Hephaestus - '09 Kawasaki Vulcan 900 Custom
90 day: 47.13 mpg (US)
Thanks: 1
Thanked 2 Times in 2 Posts
Originally Posted by aerohead View Post
As to the combustion air inlet behind the radiator,I'd recommend against that.
With the inlet ahead of the radiator bulkhead you have the most favorable pressure gradient for filling the combustion chambers.So your volumetric efficiency is already optimized.The restriction through the heat exchanger would aggravate pumping losses a little.And you'd have no control over charge density with that pre-heated air.Something perhaps not anticipated by closed feedback loop look-up tables.Don't know.
If I am reading this correctly;
? are you suggesting that my intake inlet be in fresh-higher pressure air rather than in the engine bay/warm air? I understand that for power performance, higher density and cooler charge is preferable for cylinder filling. But the interpretation I have from reading these forums is that warm air with low density is preferable for FE by necessitating that the TB plate open more to compensate for an otherwise richer fuel charge.

It would be wonderful if a higher pressure/cooler air charge could provide me with more power AND a better FE, because that is a much more budget friendly mod than the exhaust header I need to save for. I could do a CAI for just a few 10$
---although, looking at my past week avg compared to the same drive last week, I don't think that a cooler charge is better for my consumption as the weather was in the 90's last week and only ~70 this week for the afternoons.

For a little info about my engine set up;
2.2L I-4 , DOHC VVT , MPFI with electrically operated TB...really nothing fancy for these days.

Last edited by OKXXFE; 05-16-2014 at 12:57 PM..
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