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So why would GM spend all the money in developing a Swirl Port head.
It was not in their ads, nothing like our new swirl ports give you more power and MPG...and then after the years of making these extra costly head make a newer version of it. And make them for a number of years??
I think GM had a Good reason to make them and then to make them again, and it is not a sales point.
I think that at low below say 4000 the work.
I put my trust in a Multibillion Dollar Car company over a racer shop with it comes to testing how their parts work for a everyday engine.
Here is a good article by Car Craft and their chart...I like how the flat the torque curve is stock...is only 32 Ft PH from 2K to 3.5.
I have read how the peak at 2800/3000 BUT that is were the stock cam peaked as well.
The testing on a computer dyno show a great torque curve for my build.
My engine will LOVE 1500RPMs.
So by the numbers, a TPI is said to improve by 20 to 30% Torque, HP and MPG...BY themselves alone, so 14 X .20 = 2.8 14X .30 = 4.0 More MPG...so we are at 16.8 to a full 19MPG.
I have done a 16.5 A/F ratio in a 4.6 Ford and gained 4 to 5MPG, so now I am at 21.8 to 24MPG.
I had to build an engine, so I did one I feel had a best chance of making good MPG at 75/80MPH. What the hell, if it works I win, if it doesn't I still win as I will have a good drive line.
On the other hand there are a few more tricks I can add like water injection, so it might work great...either way I win.
Rich
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