Thread: Let's talk Big Bore/Short Stroke vs. Small Bore/Long Stroke Boosted

Besides the obvious torque vs. horsepower differences. I'd like to hear how everyone feels about this and maybe a little factual evidence.

I know that bigger bores tend to lift heads easier due to the surface area. I also know that longer strokes aren't as sensitive to timing. I'm debating on going with a longer stroke on the next build and I'm curious on everyone's thoughts. I've been driving a lot of the bigger 2.4 srt's, 2AZ's etc. lately and I'm very impressed with the power they're making even though they're only rev'ing out to 6500-7k. I know top fuel run long strokes with small pistons but of course we are talking nitro-meth that behaves totally different.

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Did you read Mike K info regarding long stroke engines?? Preferably that is the route I would take as for high cylinder pressure applications, I would prefer to keep the bore thickness intact and gain torque spread from stroking the engine.

does-length-matter-part-deux - by Khiem Dinh

and

Building-the-Long-Rod-Nissan-SR20VE-Engine - By Mike K and Chuck Johnson

At some point, piston speeds become an issue with stroking an engine out. As, Boostlee was kind enough to post about r/s ratio, the closer you get to 1.7 to 1.8:1 ratio of rod length vs stroke, that is the sweet spot for making an engine very happy.

For boost, I dunno as long as it is safe in the tune, it should be fine, right?

Longer stroke typically means slower engine movement which gives more time for forced cylinder filling. Another thing to think about.

Has anyone on the forums played with the longer stroke and boost?? I think it's time for a trial run. Thanks for the links @Boostlee I haven't read those yet.

I think that nobody on here has reached the limits of a 2.0 setup so why move on and spend the extra money on a strokes setup when you can make 1000hp on a 2.0.

I'd say bore all day. Your going to retain the ability to rev high. Your actually going to increase the flow of the head by having the larger diameter, putting the valves further from the cylinder walls.

Cory all your facts are true and great things to apply to a turbo motor but then again you have the prob of seeling a lot of cylinder pressure with not so much area.

With the larger studs and step deck head there should be absolutely no sealing issues. Not to mention the fact that with the extra bore you'll be making more power with lower boost pressures ......