Engine Stroking, Long Connecting Rods, Short Connecting Rods

GoreMaker

Member
Joined
May 7, 2021
Erm, no. I already stated a couple days ago that I'm leaning towards stroking to increase low RPM grunt and get the turbo spooled up faster. I just thought your observation that the increase in low-end torque is mainly caused by the increase in displacement as opposed to the longer stroke length was misleading. I could sleeve the block, run a smaller piston, stroke it to maintain the original displacement and still have increased low-RPM torque due solely to the higher piston and exhaust velocity. The available stroker kits barely add any displacement at all. We're talking what, less than 200cc?
 

GoreMaker

Member
Joined
May 7, 2021
At no point did I ever imply that de-stroking would be a solution to my search for low end torque. You're either misreading my comments or misinterpreting them because I was replying to someone else's questions. In fact I initially questioned the wisdom of de-stroking for my goals, and that hasn't changed. I'm not sure where the misunderstanding is coming from, here.
 

GoreMaker

Member
Joined
May 7, 2021
At what rpm?
Over 425 ft-lb from 2000 to 3200 rpm, with a very rapid drop-off past 4000 rpm. Peak was around 2200 rpm, though I don't have the sheet handy for reference right now. HP peaked just above 245. This was on a hub dyno (only AWD dyno available locally)
 

Ttype6

Well-Known Member
Joined
Aug 17, 2004
I just thought your observation that the increase in low-end torque is mainly caused by the increase in displacement as opposed to the longer stroke length was misleading.
The 1970 buick 455 cu. in. Stage 1 engine produced 510 lb/ft of torque at 2,800 rpm and it had a stroke of 3.9"
The 1970 455 cu. in. Oldsmobile W30 engine produced 500 lb/ft at 3,600 rpm and it had a stroke of 4.250"
These are two engines of equal displacement.
 

GoreMaker

Member
Joined
May 7, 2021
I don't dispute that, though the cam characteristics and ports/combustion chamber shapes and volumes likely had more to do with it than the stroke. Especially if we're talking otherwise-similar engines. Historically and conventionally, more stroke = more low-end torque, all other factors being equal. This is why my Pontiac 400 stroked to 463 put out substantially more low-RPM torque than a similar 455 with identical heads, cam and carb. We could quote random exceptions all day, but what I'm stating is neither radical or uninformed. It's just the commonly accepted norm.
 

~JM~

Wrinkled Member
Joined
Oct 31, 2007
Consider Leverage.

Also consider the relationship between centrifugal force, RPM & the effect of distance from the centerline.
 

Ttype6

Well-Known Member
Joined
Aug 17, 2004
Thank you. These interactions are very useful when getting used to a new forum for figuring out whose advice to take seriously in the future.
Yes, it's obvious that you came here to teach us the truth not to get advice.
 
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