PatS4P

Would someone in this forum, with the requisite knowledge, please explain to me why, with the proper components (i.e. strong as s_it) connecting rods etc. I would/would not be able to take my proposed F20C/F24C to 9000 rpm reliably as I routinely do now without the stroker? I am aware of loads on the rods, piston speed, etc. At this point in time I have a sleeved F20C block, am going FI, but reason why not increase displacement as well ? Not a big cost at this point in the game.

Atheist

Talk to an ME (other than me) and I am sure that they will bring lucidity. Saying that you are aware of loading and still asking the general question why not leads me to believe that your ideology is 'It's thicker, and strong, so even though Im changing the geometry which changes the forces, I don't see why it wouldn't work.

Maybe engineering has made me a nancy, but I do math first.

PatS4P

Atheist,

If you're referring to RSR, Toda Racing's 87mm x 100mm, 2.4 stroker kit has an RSR of 1.47:1, with a redline of 8200 rpm, straight out of Toda USA mouth today.
By contrast my RSR for the build would be 1.58:1. Rod angularity aside, if Toda
can get 8200 reliably, and assuming, as you implied that the geometry, not component integrity, was the limiting factor in higher rpm, then it stands to reason that increasing the RSR would reduce load factors allowing an increase in RPM?

But I'm not an engineer, just looking for some answers, correct ones

bigwhite

Being a Civil Engineer (not a mechanical one) I would not depend only on RSR for evaluation. there is a big parameter called "metalurgy".

for RSR vs Rpm discussions, take a look at the RSR of e46 m3, see the redline and the rsr, or simply look at b18c5.

the efficiency (VE) has a correlation with stroke, not a linear correlation-depending also on head flow etc, therefore the only way to decide the efficiency limit of our engines wrt changing strokes is to try and see method.

the keep the long story short, dont be a rsr oriented man (my semi-educated opinion)

s2k_dreams

Whoa, clicked on this thread and it's wayyyy over my head

Stepping away slowly now...

S2Kclemson

I wouldnt expect a motor with a R/S of 1.58 to reliably push 8200rpm as a daily driver. Considering the geometry involved, and not being a ME (but hanging out with a bunch at the formula SAE shop) and reading alot, I could only imagine that a daily driven car with that ratio would do best being limited at around 7500-7800rpm. At the same time, the low end torque gains would be much more significant, thus not being a huge disadvantage, considering that regular 2.0/2.2's make their power higher in the band. Those who replace the rear gears for taller ones are doing essentially what someone with a stroker is doing- creating more torque. The people who stroke the engine are doing it in the engine while those who replace the pinion and ring do it in the gearing (at the same time loosing alot of top speed in the process). Since you will be going FI, I wouldnt be so concerned about stroking the motor. If it is sleeved, just bore it out and increase the piston surface area. That would increase your displacement without changing your powerband. In all reality, the right CR with the right amount of psi (depending on the turbo that you have- efficency level is key) and a good tune should give you the power that you want. Hence- my advice to you- dont stroke it b/c it will probably be more trouble than it's worth

aids333

I would like to bring this thread back from dead to alive please.

Its interesting you guys are talking about R/S Ratios.

The lead engineer on the RS*R s2000, owner of Design Craft Fabrications - Gary Castillo uses an "all honda" 2.355 stroker with an RSR of 1.82.

There was a great article in Turbo magazine in Sept of 2006 where it documented at lenght Gary's all honda stroker. He used the block from an s2000 (F20c) the crank from a K24 and the pistons and rods from a prelude (H22a) Put it all together, like the lego set honda gives us, to created a reliable stroked motor.

What's more interesting is that he capped the oil squirters; I figured with piston speeds like that they might want to keep those in tact, but I don't an engineering background.

I love to know -at length- what would be the advantages(if any)/disadvantages to having such an increased RSR. If there are any mechanical engineers on the board who would like to contribute, or inline pro etc, your input would be greatly appreciated. There are certain factors that I simply cant speak to like dwell time and geometry that would be interesting to know when the time comes for the next project!