Boost vs. Compression.
Boost vs. Compression. Is it better to build an engine with 8.0:1 compression with 15lbs of boost, or 9.0:1 with 10lbs, or 10.0:1 with 5lbs? I think you guys get what I am trying to say. Which one will make the most power? I would think that one pound of boost would be worth more than one point of compression. I am going for the most power I can make on pump gas basicly and was wondering if I should shoot for the low compression and more boost or the other way around. I was planing on going with a twin intercooled Procharger D1sc or D1X.
12 Second Truck Club
Joined: Feb 2002
Posts: 5,574
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From: Sacramento, CA
Generally speaking it is better to have lower compression and higher boost. You'll net better results per pound of boost than you will per point of compression. If i remember correctly you usually wont see more than 15-20hp more per point of compression but you'll be able to run 2+psi more per compression point loss so you can easily double what you would have gained in compression by upping the boost.
None of my #s are exact but that is the general idea.
None of my #s are exact but that is the general idea.
TECH Enthusiast
Joined: Nov 2003
Posts: 689
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People say you lose all this low end power by going to low compression, but are you really going to notice that 20 HP you might lose on the low end of the spectrum? Do you think that extra 20 HP off idle is worth the maybe 80 RWHP you can't make up top because you're limited by how much boost you can run on pump gas? I run 7.5:1 compression in my car, low end and driveability is FINE.
If you are going to be using a D1 supercharger to make you power, then I would keep the compression around a 9:1. With that supercharger, it will be in your best interest to try and keep the boost as low as possible. Once you start belting it up for the higehr flows, many people run into severe slippage problems.
Now, if you are going turbo, I would put the compression somewhere in the 8's and crank up the boost.
Now, if you are going turbo, I would put the compression somewhere in the 8's and crank up the boost.
