11.5 Compression Ratio on 92 Octane Pump Gas Possible?

[Black1987stang]

I'm throwing together a 357W and with the heads and pistons I got the CR should be about 11.5:1...I know technically it depends on the piston/rod combo, cam and etc but for general can I run that off 92 octane pump gas? I'll be putting in a mild or if I have time, a custom cam....Thanks

[HonkIfPartsFallOff]

With the right cam it will work great. Work with a company like comp cams to get custom grind that will work best.

[Espresso]

11.5 sould work just fine.

My AMG was 11.8:1 & most Mercedes, renault & a few others run 11:1+ CR & all require nothing more then Premium(RON 91 & up) octane pump fuel.

If it is a street driven engine. ANY premium pump gas should work. Just make sure your tune is good. I've run 13.5:1 on Sunoco Ultra 94 with absolutely no trouble & under 5 counts of knock at over 7000 RPM on a SBC

[adamsvega]

with out efi to manage the timming, watch da load and knock you will loose alot in the tune up.Aluminum heads will let the same exact combo use .5 higher compression .
you can get a custom ground cam to act as "egr" during the high load low rpm area . a car on the road is not the same as a "Magazine dyno shootout" those motors are not real world streetable.
this is what they did in the 60's inadvertently. because of bad valve springs and high mass of valve train parts they ran low lift high duration wide lobe separation cams .this kept the low rpm cyl. psi down and would allow you to cruise without detonation and still have ok top end power . it aint the best but it does work over a broad range with street gears . dont crank up the rpm and timing with out better gas .
if it was me i would get a cam to use in my rpm range and fuel it according and not crutch the cam and timing .....

[Black1987stang]

Yeah it's going to be EFI, I have a Tweecer R/T piggy back so I can adjust the timing anyhow I want according to load/rpm or whatever. I can either run new world products windsor iron heads I got that came on the motor or put some more money into a set of trickflow twisted wedge heads that now has 65cc chambers so that would drop it into a much safer range. I really just want to throw a set of heads on there without putting money into another set of heads if I didnt have to.

[kxrider52]

just junk that shit

[adamsvega]

sell the steel heads to a carbguy ,ricky racer,or ebay !!!! and roll your money in the new tfs heads, lower the compression down and cam it up !!!
nothing like flat broken ring lands and lotsa blow by to tell ya that the conservative guy was right! unless ya like grenades with the pin pulled in your pocket ........ or your hard earned greenbacks aint so hard earned ....build it right and don't cut corners unless ya like pullin and rebuilding motors alot .

[PONY GUY]

I run 93 octane in my car it has the same motor 357w that you are building I have 11.5 pistions with world windsor Jr head and I have a 780 holly DP carb. I drive it on the street no problem .When I go to the track I get most of the 93 octane out and put C-12 in it . But on the street I have no issues loading up and knocking . I dont drive like miss daisy on the street with it either

[adamsvega]

engines can run along time with mild detonation/ping . the dirtier it is run the more chance ya have of the preasure spike wave pebbling the top of the piston
these motors did not fail but was found on tear down .
if the timming is off you bounce the cyl psi to high the temp goes up and and it will scuff the skirts and fold the soft ring lands when they are hot . it progresses like this and i just knew some guy would pop up and say i have the exact same engine as you and mine runs fine . there are no two identical set ups hell i know guys turbo stock motors and see how long they last !!!!

[PONY GUY]

engines can run along time with mild detonation/ping . the dirtier it is run the more chance ya have of the preasure spike wave pebbling the top of the piston
these motors did not fail but was found on tear down .
if the timming is off you bounce the cyl psi to high the temp goes up and and it will scuff the skirts and fold the soft ring lands when they are hot . it progresses like this and i just knew some guy would pop up and say i have the exact same engine as you and mine runs fine . there are no two identical set ups hell i know guys turbo stock motors and see how long they last !!!!

I never said I had the exact same engine as him . All I know is my 357W it has Iron heads comp cam duration is 502/520 (If I remeber correctly cant find the cam card) 11.5to1 pistions. I got my timing set and I run 93 octane in it for most of the time. It dont ping or knock nothing. There are other variables like spark plugs and gap, carb or injector size to I think one has to add in as well also

[adamsvega]

I run 93 octane in my car it has the same motor 357w that you are building I have 11.5 pistions with world windsor Jr head and I have a 780 holly DP carb. I drive it on the street no problem .When I go to the track I get most of the 93 octane out and put C-12 in it . But on the street I have no issues loading up and knocking . I dont drive like miss daisy on the street with it either

sound like you should re read your post or proof read em before ya click submit!!! lmao busted!!!
i cant say much more ya'll do what ya want .. i have been down this road with world steel heads and have the scrapes to prove it ... the chamber on your winsors must be the new anti ping type ....... or your math is bad or the machine shop lied!!!
post out !!!!!!