TraviZ

iTrader: (2)

I am getting conflicting results from my research as to what is safe and what is not for pump gas. I think the confusion comes from whether or not people are refering to their dynamic compression ratio with or without their boosted pressure influenced on it.
I have calculated my dynamic compression ratio at 8.1:1 and with every bit of information available using the wallace racing calculator I got 12.6:1

What octane is this safe to run on and should I rely on a meth/water injection to be safe or would it be just additional protection?

Sales@Tick

iTrader: (3)

I don't calculate it with boost normally as I have enough data to know what different compressor wheels will do to cylinder pressure.

I like 7.5:1 or less for 93 pump gas.

TraviZ

iTrader: (2)

Yes without the boost calculated in, my dynamic is terribly weak at 6.45:1

Sales@Tick

iTrader: (3)

That is plenty safe for pump gas.

TraviZ

iTrader: (2)

Even on 14psi?

ayousef

how did you calculate this? are you using seat to seat intake valve closing event values?

Give us some details, bore, stroke, rod length, SCR, altitude, and intake valve closing ABDC (mention if .050" values or what).

TraviZ

iTrader: (2)

Yes sir, ayousef.

bore:4.03"
stroke: 3.75"
rod length: 6.0"
SCR:8.162
altitude:100 feet
ABDC: 66 (http://www.compcams.com/Company/CC/c...?csid=204&sb=2)


the two calculators I used for dynamic.

http://www.wallaceracing.com/dynamic-cr.php
http://www.rbracing-rsr.com/comprAdvHD.htm

the SCR I used.

http://www.uempistons.com/calc.php?action=comp

Sales@Tick

iTrader: (3)

Yes.

I have customers running anywhere between 6.8-7.4:1 right now with 93 octane up to 22psi. Boost pressure is also not a good measure of cylinder pressure. Torque/horsepower is.