Compression ratio questions.

[DSMjunkieNH]

So I currently am building a 2.0 forged short block. question is, I live in New Hampshire and e-85 is not an option for me as its a few hours away. We have 93 oct here so I am worried about running an 8:1 compression on 93. I will be switching to race fuel when I bring it to the track but for street driving which it will be a daily, what are my options and again i know this is a touchy subject most people have a set preference but just some input would be awesome. I know how the ratio works lower compression high boost, high compression low boost. Shoot your inputs would love to hear!

 

[Talyn]

Are you asking what ratio you should run, or what you can do to run high comp and or high boost on pump gas? 8:1 is a fairly low ratio to start with.

 

[jery1234]

My cr is 10.5 & i run on 94 oct + meth injection @42 psi dd . With out meth i can safely run 28 psi on the hottest day .[DOUBLEPOST=1417883752][/DOUBLEPOST]I whould go 9.0 cr

 

[DSMjunkieNH]

yeah 8:1 is fairly low but been reading a lot about it and trying to decide what to run with the gas I have availabe here the car will be somewhere along the lines of 450-640whp on an hx40 mostly daily driven to work and shows. but a lot of people have been saying and again its my own build, but lots of well known dsmers are telling me that 9:1 for 93-94 oct is what I want but again im ganna be over 30+ psi and I want something that can handle that on hot and cold days. Granted there are a lot of other variables like headgasket, intake, all of that.

 

[keltalon]

Just go in the middle and run 9:5 to 1. I am running 10:0 to 1, My car is also my daily driver when running 93 octane I can safely run 26psi, when running E-85 I can turn the boost up to 40psi. I recently ditched my kenne bell boost a pump and install -6 fuel line from tank to filter and from filter to rail with the addition of a inline walbro ws392 255 high pressure fuel pump. when I refuel with E-85 I am going to push the limits and see what she nets!

 

[bastarddsm]

If this is your first time going big, I'd err to the side of caution. 8:1 You gain about 1.5-2% power per point of compression in this region if you can keep the timing up, however you don't gain shit if you have to back the timing way off to keep it from knocking.
Runing 25+psi on pump with 10:1 compression isn't gonna be worth a shit if you need 0* of timing to keep it from knocking.

Don't forget, low compression also pays big on VE if you have drive pressure lower than boost pressure.