mugenblacky16

Joseph, I just thought you were adding to the timing issue. Sorry I misunderstood. After reading the last few posts I'm alittle curious about this build. I'm not trying to rev to some really high rpm with my seup. If I were to guess I would say I'm looking for a max rev between 7500 and 8000. I don't think that too much unless there's something I'm missing. If it all works out I'm going to run the GSR block with the LS crank and rods w/ p30 pistons. Between the pistons dome volume and extra displacement it should result in alittle more torque and a high, but drivable CR. Since I'm using a GSR block I will be going with GSR everything else(i.e. water pump, oil pump, etc.). What do you mean by lateral load? Why would I have a "slightly lower torque curv"? Could you fill me in alittle more on that? All in all, this should be a good build. Thanks for the input and keep it coming.

Slo_crx1

Lateral loading is directly related to rod/stroke ratio. Most engine builders will agree that a r/s ratio of 1.75:1 is considered best, as it allows for high rpm and a lower lateral load. The load is the amount of force that is applied to the cylinder walls itself, obviously if the rod has a lower r/s then the sharper the angle and the more force applied to the cylinder walls. The sharp angle of the rod is where your torque is made, say compared to a b16 (which has a 1.74:1) which has much less lateral loading, but on the downside much less torque as well. B16's rely on higher rpm's to make up for what they lack on the bottom end. This also explains why your torque curve would be moved down a bit in the rpm...LS set has a slightly lower r/s ratio, therefore it makes it's peak torque at a lower rpm level.

Racintweek

throwing R/s ratio into the mix for a OEM size engine is ------- bullshit. if it was such a bad ratio then why would honda use it?? no matter what the R/s ratio is or what engine it is V6, V8, boxer, whatever, if you rev the damn thing over what was originally intended its going to wear parts faster, PERIOD. can you push the limit and still be reliable?? hell yes you can. but you cant just slap some ---- together and rev to wherever you make decent power. why dont people use cam gears to thier fullest, and lower their powerband when building an LS/VEETACK?? you can rev an LS BOTTOM end to 8K and be safe, b16's dont rev much past that, and if you shift your powerband down you dont need to rev it like a b16 and you dont loose too many rpm

Slo_crx1

Good way of dumbing it down And most b16's won't rev past 8k mostly because of the rod bolts and valvetrain. I've seen a couple with the upgrades pull 9500-10k. Not saying that reliability is an option anymore though. Point is, if you want a rev-happy motor, you're gonna spend money...alot more money than you would spend to build a turbo setup making the same power. :P

Walter

ive seem B16s with kits jun reving more than 10ks and making power thought.. all depend what setup u use..

the fact is .. high rev = more wear out will has the engine = little by little..less reliable will be the engine ... i think

Tom-Guy

No, that is what Larry Widmer says. ---- Widmer, and ---- a bunch of TOO-loving bandwagon riders. Most of what he says has nothing to do with the reality of the situation.

Revving LS or CRV geometry bottom ends to 9500 to 10K rpms I see more valvetrain issues due to almighty V-tech not being so almighty after all. The only guy I know with egg shaped bores (1 out of 9 cars I've kept tabs on over a 10K+ mile period that rev that high) also had el redneck machine shop install a set of Darton OEM drop-ins, they have sunk twice, and you don't get that quality feeling when you see how there are gaps between stock aluminum block casting and the sleeves.

Slo_crx1

I'm just saying 1.75:1 is a good number for people who want higher rpms. Hell, most F1 cars (like Honda's B.A.R. F1 car) have 2:1 r/s ration and some maybe even higher. In all honesty, I'm not one to really talk here...I'm building an ls/vtec I plan on revving out to 9500. :P If I find any issues with the lower r/s ratio JD, I'll give you full updates on what I find.

Racintweek

gm vortec 5.3l truck engine has a 1.74:1 ratio, rev that to 9K

Slo_crx1

If properly balanced and strong enough rods and hardware were utilized, I wouldn't see why you can't. The vintage race shop I worked at for a few years had a 69 camaro rs/ss with a 301c.i.d. engine used for can-am races...8500rpm's with no problems, and probably could run it higher.

Racintweek

i think something people also forget about i4 engines is that they are one of the most unbalanced engines on the planet. why do you think most 1.8l and larger engines run balancer shafts?? i'm sure that has somethign to do with wearing out bottom ends more than r/s does. you can only balance the bottom half of the rod for rotaion because the top half of the rod is moving up and down. the best you can do is balance weights of the pistons and rods


its easier to balance a V8 bottom end to sipn that high because there is room for true counter weights on the crank. the lightweight nature of most i4's internals helps with revving high and durabilty but the inherent un balance (crank end to end) is still there no matter what and i'm sure that plays a part in distorting cylinders.



?? to V8 guys; can you put a flat-plane crank into a cross-plane motor?? (with appropriate length rods of course)