Stuff to do to a sr20det

[Jeff240sx]

I'm not too sure about how to make a conjunction between revs and torque, but I think it is to have the bore = stroke.
So.  How would the JUN stroker kit help anything, as it is already a square bore/stroke ratio?
And how would boreing it to accept 300zx pistons not make it lose revs or torque?
So.. then to even things out, wouldn't you want to do both, bore and stroke it?  And if you did, the numbers still wouldn't be equal, would they?
And if anyone reading this knows, why are the s15 sr20det motor's redline 300 rpms less than other engines?
-Jeff

[William]

if the stroke is greater than the bore, the engine will tend to be more torquey than one where the stroke was less than the bore.  An engine with a shorter stroke than bore means more reving capabilitly.  This is why all (or most) bikes have a short stroke.  The point of stroker kits is to increase the displacement of an engine.  If you bore an engine over too much, the sleeves get too thin.  Stroking is the best way to increase displacement.

[crazycuban]

Any increase in displacement adds torque.  Increasing the bore is ideal, as it doesn't detract from revability, but it still gives you more torque...like William said though, you can't bore most engines very much.  The most I've seen an SR bored to is 87mm...although I seem to remember seeing 88mm somewhere.  Stroking an engine increases torque, but decreases revability.  That's why people sometimes destroke engines - to make it rev higher.  Stroke and revability aren't necessarily at odds, though - Honda B series engines all have bores of 79mm (right?), but stroke will vary up to 91mm...these are the engines so famous for their rev-happy nature, though.  The Jun stroker won't turn your engine into a V8, and it won't bring your redline down, but it will add torque.

[thich]

um??? &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/eh.gif" border="0" valign="absmiddle" alt=':eh:'>
wow. interesting......

[wherezmytofu]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (William @ Mar. 09 2002,11:55)</td></tr><tr><td id="QUOTE">if the stroke is greater than the bore, the engine will tend to be more torquey than one where the stroke was less than the bore. An engine with a shorter stroke than bore means more reving capabilitly. This is why all (or most) bikes have a short stroke. The point of stroker kits is to increase the displacement of an engine. If you bore an engine over too much, the sleeves get too thin. Stroking is the best way to increase displacement.</td></tr></table><span id='postcolor'>
i hate it when people give bad information! <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/mad.gif" border="0" valign="absmiddle" alt=':angry:'>

...any ways....stroking ass a crazy amount of stress to the engine, by making the combustion camber much smaller... u talk n mm off!....it also changes valve reveal angles, thats why stroke > bore = lower rpms....the changes of the piston hitting hte valves i increase crazy because the piston is going that much higher......this is why f1 goes destroke and bore...boring is the much safer way to get cc's.....boring thins out the walls but usually u use reinforces sleeves.....resleeve the block so, they give u a gareente like 85mm 40psi.....

....sorry i had 2 fix this

[William]

wow, that's a lot of incorrect info for me to tackle in one post, not to mention the bad grammar. &nbsp;Stroking makes the combustion chamber smaller? &nbsp;What? &nbsp;The point of stroking is to INCREASE the displacement of the engine, thus making the combustion chamber LARGER! &nbsp;And about changing "vlave reveal angles" &nbsp;I assume you mean valve relief angles. &nbsp;And yes, it would, which is one of the reasons you can't use the same pistons as you did before anyways. &nbsp;The other big reason being you would completely fuck up the piston to wall clearances and get extreme blow-by. &nbsp;"piston is going that much hgher" &nbsp;A stroker kit uses a different crank and resized rods, so you are wrong. &nbsp;"this is why f1 goes destroke and bore" &nbsp;F1 engines utilize a shorter stroke so they can rev more reliably to 18,000rpm. &nbsp;the worst thing stroking does is fuck up a rod ratio, making it smaller (it's probably too small already). &nbsp;Any questions? &nbsp;Please don't insult my intelligence, then spread incorrect information, and use 7th grade grammar. &nbsp;Class dismissed.

[wherezmytofu]

ok bad grammer....fuck that im not even american...sorry <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/sneaky.gif" border="0" valign="absmiddle" alt=':pissed:'>

now about it increasing the combusion chamber you are wrong, herez why:
1. to stroke u add length to the crank and connection rods, the cc, of the cylinders is increase because the piston downs down lower, making the cylinder longer, but this also pushes the piston higher into the combusion chamer, the cc's ina the combusion chamer is not calculated into the cc's of an engine

2. when i said valve relieve i was completely wrong, &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/confused.gif" border="0" valign="absmiddle" alt='???'> ....i ment it changes the valve angles...and not in a good way

3. in not trying to insult ur intellagence....i just u havent caught on about all the old members having the title as "newbie"..and me saying stfu newbie...so if u didnt get that joke <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/inlove.gif" border="0" valign="absmiddle" alt=':love:'> ....

4. boring is much safer then stroking, strokeing adds tremendious pressure to the block, unlike boring which is like a stock block, the cylinder wals can be thined to an extent and still by super safe

5. if my grammer and spelling is off....sorry...hope u can read it

6. stfu newbie <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/hmmm.gif" border="0" valign="absmiddle" alt=':hmmm:'>

[William]

okay, let's try this again

1) I think you have the wrong information here. &nbsp;Just because the piston goes further down into the bore doesn't mean it goes higher up too. &nbsp;The goal of stroking is to bring the piston down further on the 1st and 3rd stroke without making it go any higher on the 2nd and 4th. &nbsp;Piston to valve clearances are already tight as it is. &nbsp;If stroking actually brought the piston closer to the valves, they would hit. &nbsp;And since this simply doesn't occur on stroked engines, I have to say you're wrong.

2) I disagree again. &nbsp;Stroking attempt to change what occurs in the lower half of the combustion chamber without changing what happens in the top, and it works.

3) I have no idea what you just said, but that's cool anyways, it's hard to offend me.

4) Boring is more popular because it's easier and less expensive. &nbsp;But you don't hear people going around talking about how much they increased displacement by boring the block. &nbsp;You can do a little, but too much and it get's dangerous. &nbsp;Can you please explain why stroking adds tremendous pressure to the block?

5) Sorry, didn't know I was insulting the grammar of someone who knows english as a second language, I apologize.

6) I still have no idea what that means :) &nbsp;:)

[AceInHole]

When you just change the rod length of an engine... you're not increasing or decreasing displacement. &nbsp;It's the crank that will make changes. &nbsp;Really, if you keep the same piston slugs, you'll need a shorter rod. &nbsp;Ideally, you want as long a rod possible to keep the rod angle as small as possible, which will translate into more torque in a literal sense. &nbsp;(The rod being closer to perpendicular to the crank at 90 deg equates to a more direct force on the crank). &nbsp;
Stroking will increase piston speed, which is why it could possibly detract from revability. &nbsp;Boring an engine out will need larger piston slugs, which weigh more. &nbsp;In both scenarios, it will take more force to actually move the piston, as F = m*a, and increasing m or the a(cceleration necessary to reach piston speeds) will require more force, and will thus "add to wear on the engine". &nbsp;
Piston speed isn't necessarily a bad thing, however. &nbsp;Work is a product of force* distance. &nbsp;The piston on a stroked engine has more speed to travel a greater distance (hence it's stroked) in the same amount of time. &nbsp;The same amount of work applied to both engines... the stroked engine yeilds more force.

Boring is obviously the easier way to get more displacement. &nbsp;Less parts are required to be changed in order to bore an engine out. &nbsp;However, not only are the block walls thinned (which is the worst thing you'd want as far as strength and reliability goes) but the crank and pistons fight a tougher load, in addition to requiring a larger ring surface which may affect compression.
Stroking is harder to do (that sounds funny) since it requires more parts and more involvment with digging into the engine. &nbsp;It won't necessarily change the combustion chamber, but ithen you'll get higher compression (the difference in chamber size from TDB vs. TDC is definitely affected). &nbsp;That said... wouldn't you say similar compression would require a LARGER combustion chamber?? Remember, the piston travels further down now... it's travel being relatively larger will then call for a proportionately larger combustion chamber, so an argument on wear in this sense is unfounded. &nbsp;IMO, the longer stroke is more reliable and is more efficient.
Yes... the KA has an advantage over the SR in this manner, not a disadvantage (this is opinionated however... &nbsp;and in this same opinion, the KA's lesser rev limit is not due to it's longer stroke, but it's half counterweighted crank).
Having a square borex stroke isn't too bad or too good, from the way I see it. &nbsp;It's simply the best mathematical compromise.

Anyways, if I got anything wrong (running off the top of my head) let me know.

[William]

I agree with everything you just said, so if you were posting something in argument to what I said, it was miscommunication on my part. &nbsp;by TDB, you meant BDC (bottom dead center), right? &nbsp;Yes, if the same pistons were used when stroking an engine, a shorter rod but "longer" crank would be needed.

[AceInHole]

sheesh... why does everyone think i'm arguing?? LoL

yeah... TDB is BDC. &nbsp;
I was just elaborating, that's all.

[luey02]

It's ok to argue.. &nbsp;

You talked about wear is related to force moving the piston? &nbsp;Nah, wear only depends on speed, lubrication, and friction.. coeff. of friction that is. &nbsp;

I just wanna argue so you dont get a big head.. &nbsp;lol.. &nbsp;

willian, no you did not tell him Class Dismissed! lol.. &nbsp;I fell off my chair there..

tofo, good point on longer rods woud also decrease combustion phase volume.. &nbsp;that what I would've thought... new wife?? what happened to the last one?

[240racr]

I agree with Luey, it's ok to argue. The one good thing about it is that others get to hear a lot of different views and most of the time the correct answer comes out in the end and everyone gets to learn from it.