nightwolf_4_98

i have a motor with 10.5:1 compression and i've always ran premium in it since i got it, but where i just recently moved to doesnt have it, they only have mid grade with 10% ethonal... is this acceptable? and if not does octane booster actuly work?



maybe a stupid question but i already had to import a new motor so i'd rather not take a chance

RussellTT94

your dynamic compression is what would determine this, not the static compression.



http://www.hotrodder.com/cgi-bin/forum/YaB...;num=1103467287

nightwolf_4_98

[quote name='RussellTT94' date='Aug 23 2005, 04:06 PM']your dynamic compression is what would determine this, not the static compression.



http://www.hotrodder.com/cgi-bin/forum/YaB...;num=1103467287


[/quote]





what this apply to basicly any motor? im talkin about a 4cyl

RussellTT94

yes, it applies to any kind of piston engine. at the very least, i would retard the timing if it has been tuned for 93 and it is no longer available to you

Rob x-7

if your talking about the compression ratio of that small block in your Datsun, or any motor for that matter- just because it has 10.5:1 pistons doesnt mean it has 10.5:1 compression



the heads also determine the compression ratio, unless you have like 64cc or lower heads you dont have that compression, if you have pretty much stock heads with different valves in them then your engine has lower compression

nightwolf_4_98

[quote name='Rob x-7' date='Aug 23 2005, 06:20 PM']if your talking about the compression ratio of that small block in your Datsun, or any motor for that matter- just because it has 10.5:1 pistons doesnt mean it has 10.5:1 compression



the heads also determine the compression ratio, unless you have like 64cc or lower heads you dont have that compression, if you have pretty much stock heads with different valves in them then your engine has lower compression


[/quote]





the engine in my current DD/fun car is rated at 10.5:1 stock, i havent done any mod's to it, altho soon i'll be doing lightweight flywheel, 6puck clutch, turbo, full intake and exsaust and some valve work.. but for now im just wondering will mid grade hurt my motor or will it be alright? i have another 200 miles before i need to know but it'd be useful to know now so i could prepare..

Rob x-7

if you drive it and it pings then either retard the timing or go back to better gas,

it wont blow up on you.



how did you determine it has that compression stock anyways which would be a bit high for turbocharging in the future

nightwolf_4_98

[quote name='Rob x-7' date='Aug 24 2005, 02:59 AM']if you drive it and it pings then either retard the timing or go back to better gas,

it wont blow up on you.



how did you determine it has that compression stock anyways which would be a bit high for turbocharging in the future


[/quote]





i researched the motor before i even put it in.. i know it'll be a bit high for turbo chargeing later, but i was running 11:1 on my 510 and boosting 12 PSI with no problems.. so i think 7 PSI on this should be fine



im just being paranoid because i dont want to spend another $1200 for a motor after only a week of haveing this one up and running

Rob x-7

so you blew up the engine that came with the car?



I thought you were still on that engine

nightwolf_4_98

[quote name='Rob x-7' date='Aug 24 2005, 05:42 PM']so you blew up the engine that came with the car?



I thought you were still on that engine


[/quote]





i blew up the engine that came with the car within 3 day's of owning and maybe one day total of driveing it