Whats the benifit of a "squared" motor?
Whats the benifit of a "squared" motor? Title says it all.
From what I understand a squared motor is when the bore equals the stroke. Beyond that, I'm a little stuck for info. One example would be a 6L block and lunati crank... 4" bore with a 4" stroke, 402ci if I had my figures right.
Now, what makes this so special?
Thanks,
From what I understand a squared motor is when the bore equals the stroke. Beyond that, I'm a little stuck for info. One example would be a 6L block and lunati crank... 4" bore with a 4" stroke, 402ci if I had my figures right.
Now, what makes this so special?
Thanks,
Re: Whats the benifit of a "squared" motor? It's not really that special... I am running a slightly oversquare 4.035" bore with 4" stroke and pull it to 7500RPM all the time. It is true there will be less piston side loading if you keep the bore/stroke ratio as high as possible. Also the larger bore will allow you to unshroud and/or use larger valves for better airflow potential.
One other critical area to look at is lightening the recipricating assembly.
I would say rod/stroke ratio is probably more important. You don't want to go too wild on stroke since your piston speeds and side loading will increase as the rod/stroke ratio decreases.
Shane
<small>[ August 23, 2002, 03:49 PM: Message edited by: XtraCajunSS ]</small>
One other critical area to look at is lightening the recipricating assembly.
I would say rod/stroke ratio is probably more important. You don't want to go too wild on stroke since your piston speeds and side loading will increase as the rod/stroke ratio decreases.
Shane
<small>[ August 23, 2002, 03:49 PM: Message edited by: XtraCajunSS ]</small>
On The Tree
Joined: Jan 2002
Posts: 164
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From: Carrollton, TX
Re: Whats the benifit of a "squared" motor? The "Squared" motor allowed Ford to market a motor that did not have enough bore for the stroke ( the 4.6L ). Thats all.
Bore has no relation to stroke, more stroke than bore is obviously backward for a motor seeking RPM and power. The 5.4L ford is this.
Bore has no relation to stroke, more stroke than bore is obviously backward for a motor seeking RPM and power. The 5.4L ford is this.
Re: Whats the benifit of a "squared" motor? Like the others have said, there is nothing magical about a square motor. Essentially, what it boils down to is where you want your power.
If you want more low speed torque, stroke it.
If you want more high speed pull, bore it.
Some time back I read an article in one of the Chevy rags where they compared similarly equipped SBC's in 383 inch form (4.030" bore, 3.75" stroke) and 377 inch form (4.155" bore, 3.48" stroke). These motors had the same heads, same cam, same intake, carb, headers, all the bullshit. The 383 made more low speed power (because its longer stroke gave the piston more leverage against the flywheel), while the 377 came alive above @5kRPM and ended up laying down more peak power (obviously at a higher RPM).
Something to think about when you're looking into building a stroked or bored LS1.
If you want more low speed torque, stroke it.
If you want more high speed pull, bore it.
Some time back I read an article in one of the Chevy rags where they compared similarly equipped SBC's in 383 inch form (4.030" bore, 3.75" stroke) and 377 inch form (4.155" bore, 3.48" stroke). These motors had the same heads, same cam, same intake, carb, headers, all the bullshit. The 383 made more low speed power (because its longer stroke gave the piston more leverage against the flywheel), while the 377 came alive above @5kRPM and ended up laying down more peak power (obviously at a higher RPM).
Something to think about when you're looking into building a stroked or bored LS1.
On The Tree
Joined: Aug 2002
Posts: 165
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From: St. Louis, MO
Re: Whats the benifit of a "squared" motor? There are many factors that figure in to this, including bore/stroke ratio, piston acceleration/deceleration, rod angles, piston suface area, and many more, but basically...a "square" motor means it will make a good balance between low RPM torque and high RPM horsepower. If your stroke is longer than your bore dia. you will increase low speed torque and lose some high speed horsepower. If your bore dia. is larger than your stroke, you increase high speed horsepower, but lose some of your low end torque.
What your engine needs depends on how it will be used. For a street only engine you want to increase the low end torque. But if you plan on going Indy style, open wheel, 15,000 RPM, oval track racing, you want a much larger bore than stroke.
What your engine needs depends on how it will be used. For a street only engine you want to increase the low end torque. But if you plan on going Indy style, open wheel, 15,000 RPM, oval track racing, you want a much larger bore than stroke.
