downside for extra stroke
FormerVendor
Joined: Nov 2001
Posts: 3,065
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From: Houston, Tx.
Originally Posted by Old SStroker
Ah yes, the new "389" for the GTO. 
The new "428" (LS7) would be my preference.
How about an LS7 with a 3.27 (83mm) stroke from the 4.8L LR4 engine for ~350 cubes? Oh, maybe they already did that for the first CTSV-R.
How about an LS1 with basically stock bore and a ~3.18 stroke for a 5.0L? Think Daytona Prototype. Even with a mandated 7100 rev limit, that's only about 3760 ft/min. piston speed. To use a 3.00 crank they'd have to go past the max alowed bore or sacrifice about 17 cubes and maybe 25+ hp. They could go smaller bore and more stroke, but I don't recall anyone doing that.
The new "428" (LS7) would be my preference.How about an LS7 with a 3.27 (83mm) stroke from the 4.8L LR4 engine for ~350 cubes? Oh, maybe they already did that for the first CTSV-R.
How about an LS1 with basically stock bore and a ~3.18 stroke for a 5.0L? Think Daytona Prototype. Even with a mandated 7100 rev limit, that's only about 3760 ft/min. piston speed. To use a 3.00 crank they'd have to go past the max alowed bore or sacrifice about 17 cubes and maybe 25+ hp. They could go smaller bore and more stroke, but I don't recall anyone doing that.
Also unless the heads are designed for it when you run too small a bore they start really dropping off and most of these classes do not allow you to radically change valve spacing etc. for either larger or smaller bores so there's more to what they select than the bore/stroke ratio thing big time most often.
Originally Posted by racer7088
Louie83, this isn't particularly addressed to you but I see it coming up over and over and then people actually build these silly engines and they are always slower and less reliable and efficient and then they are confused by what they have done and don't understand.
You don't have more power when you make an engine smaller and then try and turn it more rpm. That's why we have displacement limits in racing. The bigger engines are always faster whether they turn lower rpm or the same.
Maximum displacement limits are in effect in ALL forms of racing. There is no racing where you can run as large an engine as you might want but yet not less than some lower limit on displacement. With the thousands of santioning bodies out there and tons of smart people this should give almost anyone a clue.
Now as far as the Supra well they are a joke when you look at them in anything other than turbo form. You put a big turbo on a big stroke american engine and that Supra is history.
You don't have more power when you make an engine smaller and then try and turn it more rpm. That's why we have displacement limits in racing. The bigger engines are always faster whether they turn lower rpm or the same.
Maximum displacement limits are in effect in ALL forms of racing. There is no racing where you can run as large an engine as you might want but yet not less than some lower limit on displacement. With the thousands of santioning bodies out there and tons of smart people this should give almost anyone a clue.
Now as far as the Supra well they are a joke when you look at them in anything other than turbo form. You put a big turbo on a big stroke american engine and that Supra is history.
I was not making the point that smaller engines were more powerful, but that smaller engines will make more horsepower per liter due to RPM's. If only retarded ricers knew this, then they wouldn't be bragging so much.
Staging Lane
Joined: Apr 2006
Posts: 50
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From: Chicago, IL
Originally Posted by Louie83
I was not making the point that smaller engines were more powerful, but that smaller engines will make more horsepower per liter due to RPM's. If only retarded ricers knew this, then they wouldn't be bragging so much.
hp/L is a dumb discussion anyways, just trying to figure out what he meant.
Originally Posted by njn63
i don't get what you're trying to prove there. Are you throwing out excuses why a bigger engine can't make a certain amount of hp/L?
hp/L is a dumb discussion anyways, just trying to figure out what he meant.
hp/L is a dumb discussion anyways, just trying to figure out what he meant.
Excuses? It's simple physics - do a little research.
Horsepower = (Torque * RPM) / 5252
That is the equation for horsepower, there is nothing to argue here, that is what it is.
Now, when looking at that equation, do you not agree that more RPM's will yield more HP? Obviously it will, it's gradeschool math.
Now what is going to be easier to get higher RPM's out of, a big engine with a long stroke and larger pistons, or a smaller engine with a shorter stroke and smaller pistons? Once again, the answer is obvious. Now you can see why tiny motorcycle engines can effectively make 200 HP/L.
So no one is making any excuses, it's simple physics that idiot ricers who brag about HP/L know nothing about.
FormerVendor
Joined: Nov 2001
Posts: 3,065
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From: Houston, Tx.
Louie,
What people don't seem to be understanding is that HP/L is not efficiency. It's called specific output. HP/inch or HP/L on it's own won't make you go any faster ever on it's own. If it's the same SIZE engine turining more rpm then you have more power and will go faster hence the bigger bore stuff at the same engine size.
What dumb people do is to destroke their engines! This is not adding power via a larger bore size but rather taking away power and torque by reducing engine size while NOT making the bore larger which is the only reason the bigger bore engine might make more power at all in the first place. You will have more HP/L this way but you will also have less TOTAL POWER! The best is the big bore AND the big stroke!
HORSEPOWER is what makes you go fast and that's it along with the WEIGHT of the car and how well you can hook the power up. If you put a silly *** japanese motor with WAY more HP/L into a real car that isn't 1500 pounds it will be SLOWER not faster.
That's all we are saying. It's way easier to make power with a LARGER engine including stroke than with rpm plus with good heads the big stroke engine can still usually turn just as high. I know you are already agreeing with me anyway but I think this topic confuses people all the time.
HP/Lb wins races not HP/L! You are right that HP/L is mostly based on power adders and/or rpm though. The higher the rpm the more HP/L but still the larger stroke engine will make more total power everytime and accelerate faster in the same car.
What people don't seem to be understanding is that HP/L is not efficiency. It's called specific output. HP/inch or HP/L on it's own won't make you go any faster ever on it's own. If it's the same SIZE engine turining more rpm then you have more power and will go faster hence the bigger bore stuff at the same engine size.
What dumb people do is to destroke their engines! This is not adding power via a larger bore size but rather taking away power and torque by reducing engine size while NOT making the bore larger which is the only reason the bigger bore engine might make more power at all in the first place. You will have more HP/L this way but you will also have less TOTAL POWER! The best is the big bore AND the big stroke!
HORSEPOWER is what makes you go fast and that's it along with the WEIGHT of the car and how well you can hook the power up. If you put a silly *** japanese motor with WAY more HP/L into a real car that isn't 1500 pounds it will be SLOWER not faster.
That's all we are saying. It's way easier to make power with a LARGER engine including stroke than with rpm plus with good heads the big stroke engine can still usually turn just as high. I know you are already agreeing with me anyway but I think this topic confuses people all the time.
HP/Lb wins races not HP/L! You are right that HP/L is mostly based on power adders and/or rpm though. The higher the rpm the more HP/L but still the larger stroke engine will make more total power everytime and accelerate faster in the same car.
Originally Posted by Louie83
Excuses? It's simple physics - do a little research.
Horsepower = (Torque * RPM) / 5252
That is the equation for horsepower, there is nothing to argue here, that is what it is.
Now, when looking at that equation, do you not agree that more RPM's will yield more HP? Obviously it will, it's gradeschool math.
Now what is going to be easier to get higher RPM's out of, a big engine with a long stroke and larger pistons, or a smaller engine with a shorter stroke and smaller pistons? Once again, the answer is obvious. Now you can see why tiny motorcycle engines can effectively make 200 HP/L.
So no one is making any excuses, it's simple physics that idiot ricers who brag about HP/L know nothing about.
Horsepower = (Torque * RPM) / 5252
That is the equation for horsepower, there is nothing to argue here, that is what it is.
Now, when looking at that equation, do you not agree that more RPM's will yield more HP? Obviously it will, it's gradeschool math.
Now what is going to be easier to get higher RPM's out of, a big engine with a long stroke and larger pistons, or a smaller engine with a shorter stroke and smaller pistons? Once again, the answer is obvious. Now you can see why tiny motorcycle engines can effectively make 200 HP/L.
So no one is making any excuses, it's simple physics that idiot ricers who brag about HP/L know nothing about.
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Originally Posted by joecar
If you want to mathematically compare the piston speeds of various strokes and rod lengths,
use the following formulas with math/graphical software (search web, I use DPlot):
position
= x
= r.cos(A) + sqrt(l² - r².sin²(A))
velocity
= v
= dx/dt
= dx/dA.dA/dt
= -r.sin(A).(1 + r.cos(A)/sqrt(l² - r².sin²(A))).w
acceleration
= a
= d²x/dt²
= d²x/dA².(dA/dt)²
= (-r.cos(A).(1 + r.cos(A)/sqrt(l² - r².sin²(A))) + r².sin²(A)/sqrt(l² - r².sin²(A)).(1 - r².cos²(A)/(l² - r².sin²(A)))).w²
w = dA/dt = 2.pi.RPM/60 = constant
where:
l = rod length (distance between piston pin and crank pin)
r = crank radius (distance between crank pin and crank center, 1/2 x stroke)
A = crank throw angle (from cylinder bore centerline at TDC)
x = piston pin position (from crank center along cylinder bore centerline)
v = piston pin velocity (upward from crank center along cylinder bore centerline)
a = piston pin acceleration (upward from crank center along cylinder bore centerline)
w = crank angular velocity in rad/s
You can put in the formula for v without multiplying by w
(w just scales the velocity for different RPMs),
and plot for 0° to 360° or 0 to 2.pi radians.
Keep all units consistent (convert in/s to ft/min at the end).
use the following formulas with math/graphical software (search web, I use DPlot):
position
= x
= r.cos(A) + sqrt(l² - r².sin²(A))
velocity
= v
= dx/dt
= dx/dA.dA/dt
= -r.sin(A).(1 + r.cos(A)/sqrt(l² - r².sin²(A))).w
acceleration
= a
= d²x/dt²
= d²x/dA².(dA/dt)²
= (-r.cos(A).(1 + r.cos(A)/sqrt(l² - r².sin²(A))) + r².sin²(A)/sqrt(l² - r².sin²(A)).(1 - r².cos²(A)/(l² - r².sin²(A)))).w²
w = dA/dt = 2.pi.RPM/60 = constant
where:
l = rod length (distance between piston pin and crank pin)
r = crank radius (distance between crank pin and crank center, 1/2 x stroke)
A = crank throw angle (from cylinder bore centerline at TDC)
x = piston pin position (from crank center along cylinder bore centerline)
v = piston pin velocity (upward from crank center along cylinder bore centerline)
a = piston pin acceleration (upward from crank center along cylinder bore centerline)
w = crank angular velocity in rad/s
You can put in the formula for v without multiplying by w
(w just scales the velocity for different RPMs),
and plot for 0° to 360° or 0 to 2.pi radians.
Keep all units consistent (convert in/s to ft/min at the end).
Originally Posted by racer7088
Louie,
What people don't seem to be understanding is that HP/L is not efficiency. It's called specific output. HP/inch or HP/L on it's own won't make you go any faster ever on it's own. If it's the same SIZE engine turining more rpm then you have more power and will go faster hence the bigger bore stuff at the same engine size.
What dumb people do is to destroke their engines! This is not adding power via a larger bore size but rather taking away power and torque by reducing engine size while NOT making the bore larger which is the only reason the bigger bore engine might make more power at all in the first place. You will have more HP/L this way but you will also have less TOTAL POWER! The best is the big bore AND the big stroke!
HORSEPOWER is what makes you go fast and that's it along with the WEIGHT of the car and how well you can hook the power up. If you put a silly *** japanese motor with WAY more HP/L into a real car that isn't 1500 pounds it will be SLOWER not faster.
That's all we are saying. It's way easier to make power with a LARGER engine including stroke than with rpm plus with good heads the big stroke engine can still usually turn just as high. I know you are already agreeing with me anyway but I think this topic confuses people all the time.
HP/Lb wins races not HP/L! You are right that HP/L is mostly based on power adders and/or rpm though. The higher the rpm the more HP/L but still the larger stroke engine will make more total power everytime and accelerate faster in the same car.
What people don't seem to be understanding is that HP/L is not efficiency. It's called specific output. HP/inch or HP/L on it's own won't make you go any faster ever on it's own. If it's the same SIZE engine turining more rpm then you have more power and will go faster hence the bigger bore stuff at the same engine size.
What dumb people do is to destroke their engines! This is not adding power via a larger bore size but rather taking away power and torque by reducing engine size while NOT making the bore larger which is the only reason the bigger bore engine might make more power at all in the first place. You will have more HP/L this way but you will also have less TOTAL POWER! The best is the big bore AND the big stroke!
HORSEPOWER is what makes you go fast and that's it along with the WEIGHT of the car and how well you can hook the power up. If you put a silly *** japanese motor with WAY more HP/L into a real car that isn't 1500 pounds it will be SLOWER not faster.
That's all we are saying. It's way easier to make power with a LARGER engine including stroke than with rpm plus with good heads the big stroke engine can still usually turn just as high. I know you are already agreeing with me anyway but I think this topic confuses people all the time.
HP/Lb wins races not HP/L! You are right that HP/L is mostly based on power adders and/or rpm though. The higher the rpm the more HP/L but still the larger stroke engine will make more total power everytime and accelerate faster in the same car.
Not sure why you think I don't.....
I was merely explaining why smaller cube engines make more HP/L, I was in no way saying that they were better or would make more total power than a larger cubed engine.
FormerVendor
Joined: Nov 2001
Posts: 3,065
Likes: 6
From: Houston, Tx.
OK that's what I thought and you are right that with less inches and the same heads you will lose power at a slower rate than you are losing inches. Thus you will increase HP/inch values while actually losing total power. If you're in Comp Eliminator though and they reward you with less weight for your smaller and only a little less powerful engine you will still go faster. In the real world with no weight breaks for the mini mee engine you would just go slower of course.
Originally Posted by Louie83
I agree.....
Not sure why you think I don't.....
I was merely explaining why smaller cube engines make more HP/L, I was in no way saying that they were better or would make more total power than a larger cubed engine.
Not sure why you think I don't.....
I was merely explaining why smaller cube engines make more HP/L, I was in no way saying that they were better or would make more total power than a larger cubed engine.
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From: So.Cal.
Originally Posted by THE LAST Z
Jesus Christ!
there's more (equations have been rearranged to look simpler
):https://ls1tech.com/forums/showpost....7&postcount=11
https://ls1tech.com/forums/showthrea...hreadid=501303
6600 rpm clutch dump of death Administrator
Joined: Dec 2001
Posts: 4,983
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From: Texas
Very interesting. I've been looking around for those formulas to illustrate valve opening based on highest velocity. Thanks for the info.
BTW, Erik has it right (as he always does). First off Hp/L is ricer math, and is pretty much useless.
You want as much bore as the motor will take to unshroud valves. More bore simply means more frictional losses. And, there is no replacement for displacement. Unless you are class limited, go as big as you can reasonably go....
Supra motors are basically an inline 6 truck motors that happen to take boost really well. Its not magic.
Also, a huge peak number with a usuable range of 1000 RPM and a graph like a skit jump doesn't mean anything except at a dyno shootout.
Some folks like lots of RPM on high boost motors to keep cylinder pressure more sane and keep from lifting ring lands...
BTW, Erik has it right (as he always does). First off Hp/L is ricer math, and is pretty much useless.
You want as much bore as the motor will take to unshroud valves. More bore simply means more frictional losses. And, there is no replacement for displacement. Unless you are class limited, go as big as you can reasonably go....
Supra motors are basically an inline 6 truck motors that happen to take boost really well. Its not magic.
Also, a huge peak number with a usuable range of 1000 RPM and a graph like a skit jump doesn't mean anything except at a dyno shootout.
Some folks like lots of RPM on high boost motors to keep cylinder pressure more sane and keep from lifting ring lands...
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From: So.Cal.
Originally Posted by J-Rod
Very interesting. I've been looking around for those formulas to illustrate valve opening based on highest velocity. Thanks for the info.
The link in post #49 has a simpler form of these equations.
Last edited by joecar; May 8, 2006 at 06:18 PM.
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From: Upstate NY
Originally Posted by J-Rod
Very interesting. I've been looking around for those formulas to illustrate valve opening based on highest velocity. Thanks for the info.
BTW, Erik has it right (as he always does). First off Hp/L is ricer math, and is pretty much useless.
You want as much bore as the motor will take to unshroud valves. More bore simply means more frictional losses. And, there is no replacement for displacement. Unless you are class limited, go as big as you can reasonably go....
Supra motors are basically an inline 6 truck motors that happen to take boost really well. Its not magic.
Also, a huge peak number with a usuable range of 1000 RPM and a graph like a skit jump doesn't mean anything except at a dyno shootout.
Some folks like lots of RPM on high boost motors to keep cylinder pressure more sane and keep from lifting ring lands...
BTW, Erik has it right (as he always does). First off Hp/L is ricer math, and is pretty much useless.
You want as much bore as the motor will take to unshroud valves. More bore simply means more frictional losses. And, there is no replacement for displacement. Unless you are class limited, go as big as you can reasonably go....
Supra motors are basically an inline 6 truck motors that happen to take boost really well. Its not magic.
Also, a huge peak number with a usuable range of 1000 RPM and a graph like a skit jump doesn't mean anything except at a dyno shootout.
Some folks like lots of RPM on high boost motors to keep cylinder pressure more sane and keep from lifting ring lands...
Stroke increases piston friction more than bore, and not just because of more piston speed for the same rpm. Figure the area of the cylinder wall a ring scrapes on a big bore/short stroke engine and a small bore/long stroke engine of the same displacement. The extra PS of the long stroke version makes the friction losses even worse.
Hp/L usually comes with revs. It's not a reasonable way to rate very different rpm engines. However, torque/L (or torque per cubic inch) at hp peak rpm is a fine way to compare engines. Multiply the torque/L by a constant and you get BMEP @ power peak rpm. Highest end race engines have very similar BMEPs @ power peak, regardless of displacement per cylinder or rpm. It's surprising which have the highest BMEP.
Of course go as big as the rules allow, but in much racing displacement IS limited, so how you get there is the challenge.
Staging Lane
Joined: Jan 2005
Posts: 75
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From: Boise, Idaho
Short Stroke Fan With the talk of this thread being mostly about stroking your motor I am still a fan of short stroke motor Because of the net speed of the car. 0-100-0 world record motor is short stroked. 377 Dart Alluminum Block engine. 10.8 compression, 18 deg Chapman 246 cly heads, titanium valves, comp cs254/260 R108 roller cam, .026/.028 valve lash, 93 octane, Penzoil 15w-40 mineral oil, Accel 416 plugs .040 gap, 1 7/8 headers, 750 Holley Carb. 668.3 Hp GTR. That would be my first choice if I had no budget like the owner of this Ultima GTR.
see link
http://www.ultimasports.co.uk/record.html
see link
http://www.ultimasports.co.uk/record.html
FormerVendor
Joined: Nov 2001
Posts: 3,065
Likes: 6
From: Houston, Tx.
Karlo,
That car would be faster with a better engine for sure. If it's that fast with a 377 it would be faster with a 400+ inch mill.
That car would be faster with a better engine for sure. If it's that fast with a 377 it would be faster with a 400+ inch mill.
Originally Posted by Karlo
With the talk of this thread being mostly about stroking your motor I am still a fan of short stroke motor Because of the net speed of the car. 0-100-0 world record motor is short stroked. 377 Dart Alluminum Block engine. 10.8 compression, 18 deg Chapman 246 cly heads, titanium valves, comp cs254/260 R108 roller cam, .026/.028 valve lash, 93 octane, Penzoil 15w-40 mineral oil, Accel 416 plugs .040 gap, 1 7/8 headers, 750 Holley Carb. 668.3 Hp GTR. That would be my first choice if I had no budget like the owner of this Ultima GTR.
see link
http://www.ultimasports.co.uk/record.html
see link
http://www.ultimasports.co.uk/record.html
Thread Starter
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So simply put:
If your not gonna spend any time past 6k rpm, it makes sense to stroke the engine.
If your looking to make power past 6k rpm like an N/A set up, Bigger bore & shorter stroke would be better???
If your not gonna spend any time past 6k rpm, it makes sense to stroke the engine.
If your looking to make power past 6k rpm like an N/A set up, Bigger bore & shorter stroke would be better???
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From: Upstate NY
Originally Posted by THE LAST Z
So simply put:
If your not gonna spend any time past 6k rpm, it makes sense to stroke the engine.
If your looking to make power past 6k rpm like an N/A set up, Bigger bore & shorter stroke would be better???
If your not gonna spend any time past 6k rpm, it makes sense to stroke the engine.
If your looking to make power past 6k rpm like an N/A set up, Bigger bore & shorter stroke would be better???
How about this, simply put:
"In your quest for power, go as big on displacement as you can (rules or $) by increasing the bore to what ever limits it's size (rules or bore spacing), then add stroke to get the max cubes you can. Make sure you have enough $ left to feed it the air it needs." ---The Old One
FormerVendor
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From: Houston, Tx.
If you don't need the bore for extra airflow it is rarely a benefit at all. The idea of a big bore short stroke engine having much less friction at all is mostly an idea and is not often realized at all in real tests.
David Freiberger just did the test of the two big block chevrolets in Hot Rod and as usual the bigger bore shorter stroke version did not make more power at all even at higher rpms. In fact the smaller bore seemed to pull ahead at higher rpms.
If the heads aren't really better then the big bore short stroke is usually moot. If it were true the bigger bore BBC would have had more power at all rpms from the friction reduction alone and yet this was not the case.
MANY tests have been run like that and thats why you don't see the 4.8 chevy trucks with a 4.125 bore. Remember the awful big bore GMCs. Very large bores and not too much efficiency at all. They're dead now.
Extremely big bores are good for power and not good for almost anything else. They're bad for economy and bad for emissions especially. Again even though we have F1 you still see absolutely nothing like this on the streets and nothing like this in an engine that lives and dies by it's efficiency and longevity like a truck engine.
Just think of the low piston speeds at the same low rpms if big trucks and diesels had 1.5 inch strokes! They would be so "good" and "efficient!" How about 10 inch bores and 1 inch strokes! I can tell you that this big bore short stroke engine would be a pig and make horrible tq and power and mileage.
Big Bore Short Stroke (BBSS) is not a cure all for just about anything especially efficiency (maybe breathing efficiency but not real efficiency) but it will give you good specific output or HP/Inch and that's about it and that's still providing the bore isn't too big and the stroke isn't too small of your compression becomes impossible.
David Freiberger just did the test of the two big block chevrolets in Hot Rod and as usual the bigger bore shorter stroke version did not make more power at all even at higher rpms. In fact the smaller bore seemed to pull ahead at higher rpms.
If the heads aren't really better then the big bore short stroke is usually moot. If it were true the bigger bore BBC would have had more power at all rpms from the friction reduction alone and yet this was not the case.
MANY tests have been run like that and thats why you don't see the 4.8 chevy trucks with a 4.125 bore. Remember the awful big bore GMCs. Very large bores and not too much efficiency at all. They're dead now.
Extremely big bores are good for power and not good for almost anything else. They're bad for economy and bad for emissions especially. Again even though we have F1 you still see absolutely nothing like this on the streets and nothing like this in an engine that lives and dies by it's efficiency and longevity like a truck engine.
Just think of the low piston speeds at the same low rpms if big trucks and diesels had 1.5 inch strokes! They would be so "good" and "efficient!" How about 10 inch bores and 1 inch strokes! I can tell you that this big bore short stroke engine would be a pig and make horrible tq and power and mileage.
Big Bore Short Stroke (BBSS) is not a cure all for just about anything especially efficiency (maybe breathing efficiency but not real efficiency) but it will give you good specific output or HP/Inch and that's about it and that's still providing the bore isn't too big and the stroke isn't too small of your compression becomes impossible.
FormerVendor
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From: Houston, Tx.
Take apart the idea of the BBSS for a sec.
Within reason bigger bores are enablers for better cylinder heads and this is what makes more power.
Shorter strokes only hurt power and tq numbers in real engines.
BBSS only makes sense if you have rules or want less power but at a higher rpm?
Who wants less power from a performance or any engine for that matter?
SO if you want LESS power and tq than destroke.
If you want more power and tq then add stroke.
If you want a lot more power go bigger bore and bigger stroke!
Within reason bigger bores are enablers for better cylinder heads and this is what makes more power.
Shorter strokes only hurt power and tq numbers in real engines.
BBSS only makes sense if you have rules or want less power but at a higher rpm?
Who wants less power from a performance or any engine for that matter?
SO if you want LESS power and tq than destroke.
If you want more power and tq then add stroke.
If you want a lot more power go bigger bore and bigger stroke!
This topic comes at a good time for me. I'm thinking about a stroker motor and I'm slightly worried about a sleeved LS1 {4.100 bore} with a 4.100 stroke. Will the piston have plenty of support when it's at the bottom of it's stroke? I'm worried that the piston skirts will actually be coming out of the cylinders at the bottom causing problems with piston rocking??? No idea, any opinions?
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From: Upstate NY
Originally Posted by racer7088
"Within reason bigger bores are enablers for better cylinder heads and this is what makes more power."
"If you want a lot more power go bigger bore and bigger stroke!"
"Extremely big bores are good for power and not good for almost anything else."
"If it's the same SIZE engine turining more rpm then you have more power and will go faster hence the bigger bore stuff at the same engine size."
"Maximum displacement limits are in effect in ALL forms of racing."
Well said.
