Quote:
Originally Posted by beatr911
Just increasing the stroke will yield a bigger displacement engine with an increase in torque, yes, but won't do anything for mileage unless you need more torque than you already have. Increased output from an engine means it uses more fuel (you knew that). Increased efficiency is usually when the engine is operating at it's maximum output for a specific RPM, wide open throttle eliminates the massive restriction of the throttle plate.
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Yep, its a dance between fuel econnomy and power.
Quote:
Originally Posted by beatr911
Of course for any significant stroke increase you'll need to change rods and pistons to accomodate the block it's in. Compression ratio could then be whatever you want.
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I'm looking at going to 9:1 from 8:1, not much stroke difference, even the stroke that I am looking at going to I am wondering if its going to be worth the money.
Quote:
Originally Posted by beatr911
Optimizing the engine for low speed operation and low maximum power output to what you'll routinely use can be done more efficiently with cam timing and intake and exhaust header length. Increased compression ratio will also help by milling the head or decking the block, or by pistons. Low tension rings help, single ring pistons help. Cam profile changes minimizing overlap will help. Potent ignition systems help. Optimized ignition timing helps. Very accurate carburetion settings or ultra fine injector spray patterns help.
Hope this helps!
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It does, It helps confirm that some of the modifications I am wanting to do will do more than just increase the low RPM torque.
The planned mods inclued
Long tube header,
cam with low to no overlap,
increased compression to 9:1,
smoothing the intake and exhaust ports
smoothing the cylender head chamber
the head off of a 4.0 (already have)
fuel injection (already have from the 4.0, just missing the ECM)
edit: distributorless ignition (from the 4.0)
The head and fuel injection alone should get me a 30-50% increase in mileage, as well as more available power, and cleaner emissions.
Mods being considered (debating the cost/benifit)
slightly longer stroke
piston and head coating
roller cam
roller rockers
paying someone to do the more advanced work for me
