Can someone explain displacement to me? - Page 2 - LS1TECH - Camaro and Firebird Forum Discussion



Can someone explain displacement to me?

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Old 03-03-2017, 06:00 PM   #21
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Originally Posted by TheUrbz View Post
i honestly could have said HP following the TQ line, thats just what i typed first.

so although the "power" is the same, the ability to lay it down is what the advantage is for stroking. so witha 350 and a 383 having the same HP, they will have the same top end, but the 383 will get to it faster, right?
Having more stroke typically makes the torque curve flatter and longer (more low end torque).
But yes to basically what you are saying.
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Old 03-03-2017, 06:20 PM   #22
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Originally Posted by JD_AMG View Post
Having more stroke typically makes the torque curve flatter and longer (more low end torque).
But yes to basically what you are saying.
thank you. for the life of me i couldnt get anyone to answer my hypothesis in person. from my toddler perspective, you stroke a 350 to extend your power range when youve done all you could, to get what you could, out of a 350 so i just couldnt understand that if you can make the same power out of a beefed up 350 (from reading on here) then why would you bother stroking it. but to the layman, HP is god and if your number is higher than the next guy, then that means you'll lose.

I knew that was all wrong from the get go cause you have to factor in all sorts of other variables, and torque seems to be the one least understood for importance to the john everyman...i mean...i knew it was important but thats because again, my douche friends drive trucks blah blah pull this and mud that cause of muh tork.
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Old 03-03-2017, 09:55 PM   #23
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Originally Posted by NewOrleansLT1 View Post
But 350 vs 383 giving all things are the same the 383 should make roughly 30hp more.. I don't have any proof.. Just going off word of mouth..
I had a 383 once upon a time in life. It made decent gains over my 346 but the real noticeable jump was in torque.
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Old 03-05-2017, 03:33 PM   #24
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Old 03-05-2017, 05:39 PM   #25
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that's the exact video I watched that made me ask "then why the hell is it so damn important to just gain all that tq but only 8 hp." Now I'm learn-ned.
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Old 03-05-2017, 07:46 PM   #26
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that's the exact video I watched that made me ask "then why the hell is it so damn important to just gain all that tq but only 8 hp." Now I'm learn-ned.
As you see in the video the heads was chocking the 410ci motor.. If it would have had bigger heads it would have sored pass the 367ci engine..
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Old 03-05-2017, 08:05 PM   #27
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As you see in the video the heads was chocking the 410ci motor.. If it would have had bigger heads it would have sored pass the 367ci engine..
right. I understood if they had better heads on it it would have flown but they were kinda comparing apples to apples, showing the difference in the torque you gain if you didn't change anything else. My only limiting factor is to keep mine NA hence why I was researching 383s. When I ran across that video they didn't go much into what that increase does in regards to a vehicles performance so it didn't help my limited understanding of the importance of torque.
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Old 03-05-2017, 09:43 PM   #28
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This seems appropriate
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Old 03-06-2017, 05:55 AM   #29
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With the same heads and same cam, only going from a 350 to a 383, you move the HP peak to the left (earlier). Since HP = TQ * RPM / 5250, you are getting your peak torque earlier, because you do have slightly more cylinder vacuum pulling the air through the heads, it pulls in the air sooner (earlier) but is still restricted by the tiny air path. On a 350, it has to get to a higher RPM to suck in the full breath, the 383 gets a full breath earlier. I'm trying to break it down very simply, not taking into account scavenging, momentum, swirl, and port velocity, there are a ton of other little things going on that account for power. Part of it is basically terminal velocity of the air coming into the motor, if the air can only enter the head at X mph, you are going to hit that limit at a lower RPM on a bigger cube engine than a smaller one with the same heads because the 383 takes in more air per breath. The 383 will make more power, not a ton though, it comes down to HP/$, if you are building a motor, you will get more power from a $3000 good heads and cam, than spending that $3000 on more cubes and not touching the heads and cam.
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Old 03-07-2017, 09:12 AM   #30
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Power under the curve also comes into play with these strokers.
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Old 08-07-2017, 10:01 PM   #31
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Originally Posted by TheUrbz View Post
thats partly what im missing. yea if you stroke an engine but not change a damn thing else youre wasting your time. but as you say, if you built them equally, your gain might be 30 more horses. the hells the point then. the point im told is tq and the difference in powerband. fantastic. again, why would that be important. you take a 350, mod the hell out of it, then rev it up higher than the national debt and you got lots and lots of power. Stroked engines dont rev high. i have seen exceptions but in general, there not for reving. so i dont know why going through all that work to have POTENTIAL but you can get the same out of a 350.
Well you can only rev a 350 so high... Then the drivability goes out the window at cruising speeds because your power band is soooo high that you have no guts down low.. But if you stroke the 350 to let's say a 383 you bring the power band down some getting your drivability back WITH the potential to make even more power (with bigger heads, cam, etc).. And the process goes on and on the bigger the engine gets...
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