KOZ RACING
New member
Looking for suggesting on going big bore or stroker. 1/12 mile bullring which set up would be better. Thanks
Big bore or stroker
- Thread starter KOZ RACING
- Start date
rotaryicon42
Member
big bore. more low in power. on a little track you need torque
astrowrench
Member
Stroke is what gives you TORQUE duh
65ShelbyClone
Member
It is of little consequence when the displacement remains constant.
With a big bore, the cylinder pressure has more piston area to push against (= more force on the crank throw), but it pushes against a shorter "arm" (stroke).
With a long stroke, the cylinder pressure pushes on a smaller area (=less force), but it has more mechanical advantage (longer stroke).
When the displacement doesn't change, the swept volume doesn't change which means air speed through the head doesn't really change and ultimately the power delivery doesn't change.
With a big bore, the cylinder pressure has more piston area to push against (= more force on the crank throw), but it pushes against a shorter "arm" (stroke).
With a long stroke, the cylinder pressure pushes on a smaller area (=less force), but it has more mechanical advantage (longer stroke).
When the displacement doesn't change, the swept volume doesn't change which means air speed through the head doesn't really change and ultimately the power delivery doesn't change.
astrowrench
Member
Possibly in your book; But In the real world take 1950 Chrysler straight 8 327c.i. Flathead vs 327 chev.327.c.i. OHV & Speak to me about Torque been there done it (327 the correct way in a row)
65ShelbyClone
Member
How are those two engines even remotely similar? Flathead I-8 vs OHV V8? Come on.
jsstump#70
Member
The old oversquare, squared, undersquar debate. Olds, Buick, and Pontiac 455 guys have debated this since the early seventies. All could be made to run. Never really settled or proven to be a clear winner when truly equally compared. In this case I would pick the stroker. It can be a real pain to get some of the bigger bores to seal. Not much area to work with. O-rings and raised sleeves are about the only semi-reliable way. Good luck.
metalmagic
New member
Stroke gets u out of the corner... While bore gets u to the end of a long straight with rpm.... So on a small track go stroke all day
Id agree with this. Or possibly go with a .010 or .020 overbore and stroke it as well, and do some work to the head to help get a little more power out of it. On a small track, you want as much low end torque as you can get, because your constantly in the midrange of the power curve and are in and out of the throttle. I would also work the carb to get the best throttle response you can get, that will also help alot on a small track where throttle response helps.
I am old and familiar with engines.
Your previous reply with the Duh was rude and unnecessary.
I do not know your point in the comparison.
Your 1950 straight 8 is a 323ci not 327(irrelevant), but it had a bore of 3.25" and stroke of 4.8" producing a massive 270 lb/ft of torque.
Chevs V8 327ci bore of 4" stroke of 3.25" with a 4 barrel carb produced over 350 lb/ft
Yes stroke is advantageous to produce torque, but you didn't choose example very well. You cannot compare a straight 8 flathead to a OHV V8.
That is like comparing a stock Briggs flathead to a stock clone.
flattop1
Dawg 89
Personaly I vote stroke. On the ease of assembly issue. also with out doing any math typically you will gain more cc with stroke increases than with bore increases. Assuming your not talking about using a max stroke crank, which will yeild minimal increases in cc's.
again assuming a modified engine, not a stock legal blueprinted akra / wka type.
again assuming a modified engine, not a stock legal blueprinted akra / wka type.
sneaks12303
Member
Why not do both ?...Until the 60363 Predators my fastest motors were 2.77" Wiseco long rod with the NR .060" stroker crank...
Freezeman
Site Supporter
How is the displacement not going to change with either a longer stroke or bigger bore 65Shelbyclone?
youngengines
Member
I think he means either stroke , or bore..as long as the change in displacement is the same...power will be the same. Now I believe that to a degree, but what I have seen, longer stroke will make the peak power at a lower rpm than the shorter stroke, bigger bore. Geared correctly I would wager there would be very little on track difference. JMO
sneaks12303
Member
A 3" piston big bore OR an Arc .175 stroker are NOT easy builds. Both have their challenges and are expensive . But a 212cc (2.75") Predator 60363 short block and a smaller stroker crank like .060" and your favorite head...Best of both worlds that anybody can build.... SWEEEET, and cheap...
astrowrench
Member
What was the clutch engagement torque on the sb.chev? and overall width of the torque band? My Point was simply speaking stroke produces more constant and a broader torque band starting at a much lower rpm and remains smooth and progressive as rpm increases;with out a doubt the V8 would produce more ultimate torque,but look at the torque and horsepower curves, the long stroke Flathead is much more consistent I assumed wrongly that this would be understood, my bad.
Minidragbike
Member
A stroker, or big bore would give you both TQ and HP.
Minidragbike
Member
The big bore helps more than stroke. Simply because it makes more CC than the stroker crank. And it also improves head flow.
Getting more dynamic compression in from flow, and compressing more with the added CC making a higher static compression makes the most power.
Getting more dynamic compression in from flow, and compressing more with the added CC making a higher static compression makes the most power.
KOZ RACING
New member
Thanks to all this is great to get all these different outlooks. I now have more to think about lol. Thanks again guys