im runnin 11.5:1 CR on my rex and i was wondering if 92 (premium) fuel was good enuff. my friend said its not but im not sure. the RSX type-s is 11.0:1 so its not that much different...

 

yes

 

Yes 92 octane is fine. Just think about this the toyota celica gts compression is 11.5.1 stock and people put shitty 87 octane in those cars all the time. Even though the toyota engineers are aware of how cheap Americans are so they run rich from the factory, a lot of car manufactures do it you would be surprised. Even the porsche carrera S or one of them I can't remember at the moment has a compression ratio of 11.8.1. Its the porsche with 355hp NA.

 

I believe the reason the Celica and Carrera's can run 87-91 octane[all we get here in Cali] is because of tuning. I've seen a 13.3 CR B16B run fine with Uberdata and some good tuning. JMO - Darrell

 

My JDM ITR motor (11:1) seems to run fine on 91 octane. So I would think 11.5:1 should be fine on 92 octane.

 

i guess i take for granted that here in florida we get 93 octane anywhere. you can even come across 100 octane unleaded near the speedway

 

how high CR can i go w/o having to retard the ignition at all?

 

Its all about tuning. If you are spending the time and money to build a motor with compression that high then spend the extra cash to get it tuned to run on street gas. Retarding and advancing your ignition is not going to fix the problem. Maybe temporarily to limp it to the dyno for some tuning but not to daily drive around on... at least get some type of base map.

 

Also keep in mind that when deciding on a compression ratio, you will have more power if you run a lower compression ratio that requires no timing retard than if you run a higher compression ratio, but have to retard timing. So don't go for more than available pump gas can support unless you plan to use nothing but race gas.