math and engines dont mix. see the terrible results of turbo sizing and math i've made in the last year or so.

only to a certain degree can you put math and theory into a motor. The rest is R&D and just trying shit. Cam profiles and timing affect compression GREATLY. A 9:1 compression motor at 9psi should never ping on 93 octane right? i've driven one that did. I've also driven/tuned a car with 11:1 and 9psi on pump gas. Didnt ping a bit. Cam choice and cam timing affect when the highest cylinder pressure occurs at how many degrees ATDC. I've read/heard from the best builders that you want the highest cylinder pressure to occur 14 degrees ATDC. is there a way i can test that? not right now. until then i'll just play on the dyno with cams, cam timing, and ignition timing. And now a knock sensor is my best freind.

you are on the path to learning just open you mind a bit. i dont think 130 octane fuel exists in our racing industry. but if you have a 50 gallon drum of it from an airport your dads farm or something more power to you.

 

i still dont understand BMEP.

one thing i have noticed, my 8.5:1 15psi motor loved to max out my 550cc fuel injectors. my 11:1 15psi motor stuck them at 74% duty cycle with the same a/f ratio.

then on another motor with same interals just changed to a huge turbo, it required less duty cycle out of the same size injectors than my smaller turboed motor. we both had the same car and same setup, he just had a bigger turbo.

 

Just because you have a crx, does not mean that is the type of engine you are going to be using when doing this type of thing.... so yea it did make u sound like a dick....a lot of people do swaps in their crx's instead of building up the stock engine

 

Something I noticed on the first page he talked about "de-stroking the crank" and also "shorter rods". You're kickin yoursefl in the ass twice right there. You could do one or other, but doing both would just hurt you unless there's some magical Honda fairy that makes it work better.
Normally, people stroke their crank and use a longer rod to achieve a better rod/stroke ratio. This is from V8 land though, so, the Honda building may be different.

 

This doesn't make sense to me unless you are adding to the deck of the block. How do you use a longer stroke crank and a longer rod yet keep the ring package above the piston pin and not push the piston out of the hole?

 

With the old V8s, they're running 7.5-8.5 CR back when the emissions hits were starting to come on. So, we can stroke the crank a little and use a little more rod, and be close to zero deck and up the CR to around 10:1. The crank only get's stroker about 0.211" and the rods are about 0.750" longer. You should see how deep in the hole my pistons are with a 8.5:1 CR and a 62cc chamber.
Those numbers are just estimations, different crank stroking needs different rods.

 

Alright, I wasn't thinking of static CR's that low. It makes a little more sense now. Does the pin placement change any?

 

in certain applications, yes!

 

That would make even more sense.

 

well...say for example you want to build a 350 chevrolet motor. stock they have a 5.7 inch rod. lets say you want to use a 6 inch rod and still have a reasonable c/r. if you look in jegs or summit you will see pistons that are designed specifically for that application. hence the revised pin location. the reason for the longer rods is to slow down the piston speed and to keep the piston at top dead center longer!! make any sense???