Originally Posted by oldhp
ramvan2500, Everybody lives around here so altitude is same. I build engine as a package including rear gear and tire height. It all has to work together.
750 double pump, huge cam, open plenium intake, 10 to 1 compression, 3.55 gears, 28" tall tires and it won't drive good around town. Hmmmm...
210* is for emissions.
It'll be interesting when these tuners come out.
Well I don't know how the terrain is where you live, where I live the altitude ranges from sea level for about 200 above sea level... But I design precise engines, transmissions, cars. So when I solve all the equations I run everything at 1 atm. And when I figure for thermal expansion I always start with a measurement at room temp. But I'm an engineer so for thoroughness I have too. I am not that familiar with the Hemi so I didn't know what the stock thermostat is, I know for the Magnum but that's about it.
But I am glad to hear you build an engine around gearing and stuff. But tire height isn't everything you have to remember things like moments of inertia etc... But what is your definition of street manors when it comes to cars? I drive like Mario Andretti and Dick Landy combined with the shifting of Ronnie Sox. Just call me Frankie 4 Spd.
Anyways I can tell you first hand there isn't any direct way no calculus that I can do to tell you which octane runs best, that is what brake dyno's and calibration is for. I can build a 4.2L V8 that puts out 400+hp 400+ ft-lbs, 10.5:1 SCR 8.2-8.5:1 DCR (I build based on room temp engine and engine at op temp thus the 8.2-8.5) that gets 20 MPG and runs 89 octane and does have street manors relative to most drivers. But of course it runs around 5-6 grand to build and most people aren't going to drop that and I don't build those engines to sell, I actually don't build any engines to sell. I am stingy that way, I build transmissions to sell though no problem. Personally I love building transmissions more than engines, but I love to design engines. Anyways just go with the manufactures recommendations, the people who designed your engine are doctors of engineering and they have the support of a billion dollar company that has a history of engine building probably longer then your and I combined. But don't let that stop you from experimenting, that is how most of the technology we have was founded.