What would compression change? Educate me! Help!
09-15-2010, 09:37 PM
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What would compression change? Educate me! Help! Ok well I did a build with a 408 with -10cc pistons and tfs215s milled to 61 with a gasket at .40.. After being told that I would be close to 11.1 from tsp now finding out I'm closer to 11.14-1.(guy from here did the math). Where would this put me for nitrous and what would it effect? Just trying to figure out the ups and downs to this? Help please.
09-16-2010, 11:20 AM
#2
There will be almost no difference between 11.1:1 and 11.14:1. That difference in calculation can be seen just by using different calculators. Nitrous prefers higher compression motors so if anything that works in your favor. IMO for an N/A nitrous build, the more compression you can get the better. It just leaves you with a more responsive motor.
09-16-2010, 01:41 PM
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High compression is both good and bad for a nitrous engine. If the nitrous system is properly tuned an IN CONTROL, then it's almost all good. If the nitrous system is badly tuned or steps out of line, then it's worse with higher compression (blown hg, etc).
Higher compression means higher expansion ratio. This captures more effectively the extra work done by the charge. Just like with an NA engine. It also shifts the angle at which most of the work is done ("work" in terms of physics) earlier, allowing you to open the exhaust earlier and help th extra exhaust volume get out.
h
Higher compression means higher expansion ratio. This captures more effectively the extra work done by the charge. Just like with an NA engine. It also shifts the angle at which most of the work is done ("work" in terms of physics) earlier, allowing you to open the exhaust earlier and help th extra exhaust volume get out.
h
09-16-2010, 10:48 PM
#5
that .04 difference could just be a different gasket dia, or someone accounted for the area above the ring land, etc. Unless you cc'd every chamber and piston dish, along with the exact piston to block deck height measurement, and compensated for all of it, you'll probably have more of a difference within the engine itself. AND, that difference is quite negligible.
