De-stroking Motor

[22crazy]

was i reading through some pages and i seen sum dude in sweden that has a golf de-stroked from a 2.3 to a 2.1....he did this because it gave him more rpms. Could u do the same with a h22, or a b20/b18/vtec. Thanx

 

[xj0hnx]

Yes,I've read of a couple people doing it.

 

[22crazy]

ya but what are the effects....advantages, disadvantage...is it good for boost....how do they do it?(like what is involved theorically)

 

[xj0hnx]

Originally posted by 22crazy@Jan 27 2003, 10:37 PM
ya but what are the effects....advantages, disadvantage...is it good for boost....how do they do it?(like what is involved theorically)

I'm not as mechanically inclined as some on the site,so I'm not going to feed you a bunch of bs about how to.But you got the theory right.

 

[22crazy]

im asking how it is done, i dont no the theory that is what im asking...as well as everything i asked b4

 

[RENR]

no replacement for displacement fellas!!! who cares about higher rpms if it isnt gona help and wear out your motor faster.

 

[xj0hnx]

Do you want me to feed you possible bs?here goes,destroking it helps it achieve higher rpms because the new r/s will be closer to perfect,and shorter there by putting less strain on the springs and valves due to rotational force being lessened,as in the case of the b16,which is a high revving low displacment engine.To do it you would need the proper rods,pistons,and crank.I don't know how much of this is accurate.So please someone fix it.

 

[Domeskilla]

Originally posted by 22crazy@Jan 27 2003, 04:48 PM
im asking how it is done, i dont no the theory that is what im asking...as well as everything i asked b4

You take a bigger block and sticking a smaller crank in it.

I will use a domestic since i know more about them.

A 350 with a 400 crank = 383 stroker. The bigger crank revs faster, making more low end tq.

A 400 with a 350 crank = 377 destroker. It has a smaller crank in it. It makes its powerband start higher up in the rpm range. That is why you hear NASCAR cars rev to like 5-6k before they drop the clutch in the pits. A 377 is what the NASCAR guys who run Chevy's use, b/c it lets them rev at 8-9k all day long.

 

[dohcvtec_accord]

Also, you'd need cams that could make power at the higher rpm's. It won't do you any good to raise the revlimit if the entire valvetrain (not just springs and valves) can't support the higher rev's or can't make power up there.

RENR, why would you say it wouldn't help? If you didn't do any of the above mods, you'd be right. But if the head were built correctly to accept the higher revs, it could only be good.

 

[lsvtec]

There is no reason to destroke any of the engines that you listed. All of their respective R/S ratios are good enough to take street driving (meaning I would trust my LSVTEC to 9000 or 9500 with the right parts but no way would I want to go 10,000 or 11,000). Why sacrifice the extra displacement?

 

[dohcvtec_accord]

Honda engineers must have had some reason to create the F20B, which is more or less a destroked H22.

 

[lsvtec]

Maybe for the same reason the Civic Si has a K20, but not the cool K20. They didn't want it to compete with another car already in production (Prelude Type S).

 

[dohcvtec_accord]

I suppose. But it still outputs 200hp to the flywheel. They could have just dumped an H22A in there. Seems like an awfully long length to go to (engineering a new engine) just to mess with power outputs.

Ehhh, I should just stop trying to understand their decisions, especially after looking at the new Civic Si.

 

[lsvtec]

If what I have been told about the F20B is true they didn't design a new engine, they just destroked the H22A. Just like The B17 is a B16 with a larger stroke.
The Civic is having an identity crisis. "Am I a hatch or am I a mini van???"

 

[dohcvtec_accord]

I've heard differing opinions on just what happened with the F20B. So I'm not even sure.

Civic Si: The product of a drunk Focus and a rapist Odyssey.