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Old 12-30-2017, 10:13 PM   #1 (permalink)
Phoenix'97
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Location: NY
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White Steed - '97 Pontiac Firebird Trans Am WS6
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Lightbulb How to build a muscle car for better fuel economy?





In the not too distant future, I plan on modifying my car's second-generation LT1 motor to make it a better daily driver with emphasis on shifting it's stock torque curve down to lower RPM range, where the car spends most of it's time in city traffic. Now, I don't race this car and I have no plans on taking it to a track, I even drive this car in the heart of the winter in decently deep snow! So, this is where I have to balance power production with fuel economy, which I would prefer to maintain with the given EPA estimates. The automotive performance forums are only so helpful since those guys specialize in building race cars and not the opposite side of the spectrum where I am at.

So, as a starting point for my build goals with my LT1 motor, I am very set on modifying a Tuned Port Injection intake manifold to fit on my LT1 heads, to use AS&M big runners and to have the plenum, runners, and manifold bottom port matched, gasket matched, and extrude honed. I plan on using 180cc DART heads since they emphasize port velocity, which is great for low end torque production and in my mind, helps in overall fuel economy. I also plan to use long tube headers designed to emphasize low end torque which are customized to work with my emissions devices and will use catalytic converters. Also, for the sake of better efficiency, using Iso-butanol fuel to allow for a higher compression ratio of up to 12, equipping my motor with smaller low friction bearings, piston skirt/bearing/valve stem/valve spring/crankshaft low friction coating, low friction crankshaft seals, and a true roller timing chain.

The last modification deals with the camshaft. After some research I found that the widest lobe separation is the most optimal for fuel economy, and such a lobe separation at 117 is what I have for my stock camshaft. I am left wondering if there is anything I can possibly do to improve upon the stock camshaft profile, increasing the lift for any marginal performance gain without sacrificing fuel economy. I do think the stock camshaft should be advanced to help improve the lower end torque that my car really needs, but again, I only have so much help using other forums that don't specialize in what I wish to achieve with my muscle car and daily driver.

So, what do you any of you think about these ideas to modify my second-generation LT1 motor for better fuel economy and a good enough increase in the "seat of the pants" performance.

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Last edited by MetroMPG; 12-27-2018 at 12:32 PM.. Reason: (added image for posterity)
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