All these posts are completely false statements and are common rumors. I run 10:1 compression on 93oct with my 2.4LR i built w/o any issues, all you need is a good tuner. Sure I'm not making the 700+whp on that tune due to boost turned down to 26psi and pulled some spark advanced timing, but it drives strong w/o any knock. I even built a inergra type r a few years back running 11:1 compression w/ 35r that was daily driven on 93oct that Norris tuned and it still runs flawlessly. Again, you can run higher compression on premium gas all that's needed is a great tuner, lower boost, and some timing or spark pulled back.

Ps: I don't have any dunno numbers yet from my current build but I would guess I'm in the high 500s on 93oct comparing it to my last setup on the stock block.

 

same here on my second 10.1 motor most good tuners are not having a problem running 30lbs on pump gas with 10.1 as long as the ignition is up to par and you have a good tuner shouldent be any problems mason any info on this Torco fuel accelerator ?

 

http://torcoracefuel.net/pro-accelerator.html

http://torcoracefuel.net/2-docs/acce...r-ratio-93.gif

1 quart which is about $25 if you just buy it by the quart will raise an EVO tank of 93 octane up to 100+octane.1 quart will raise 10gallons to 104octane.you can also buy a 5 gallon bucket for like $300 shipped which is 20 quarts.the stuff works as advertised.i have tried it.

you missed the entire point.fact is that you could run 29-30psi with the same timing on your car if you were at 9:1 instead.the extra 2-3psi of boost you can run with lower timing will outrun the gains you got off going from 9:1 to 10:1.fact is 2-3 psi of boost is good for 60+hp on that GT35 and going from 9:1 to 10:1 increase in SCR is good for maybe 25hp.

if you can run the same boost on 93 at 9:1 as you can on 10:1 then by all means go with the 10:1,thing is most cars can't.fact of the matter is there is a point where rasing SCR will hurt you on 93 octane,if you don't believe it then you can't be helped at this point.

 

A high CR also increases the risk of detonation with low octane fuel. Regardless of tune, the risk is still there.

 

I agree 100%
8/1 would be my choice for low octane

 

No more than 9:1 for a dual purpose engine, E85 and low boost on pump then 10:1 but based on my experience 20-21psi is really the safe limit on 92. A straight pump motor I would still probably leave it at 9:1 as the 8:1 and 8.5:1 motors just dont seem to have the snap I prefer and really seem to run out of octane at the same point, least on 92.

FWIW I made 648/477 at 29psi on 92 octane without additives.

 

Hey john will there be big power diff if I ran 9:1 compared room 10:1 on e85? I feel like the pump e85 is inconsistent.I have 93 over here don't know what I can get out of that with 6266 thanks

 

John,what was the SCR of that motor that made 648 on pump,9:1?

if you can make 29-30psi with a 9:1 SCR,shouldn't you be able to go a little higher than 22psi on a 10:1 motor.i figured only a few pounds of boost per SCR point?

 

My question is will 10:1 motor on e85 make more power then 10:1

? Bboth same modd besides compression

 

if you meant will 10:1 make more than 9:1 on E-85,then the answer is yes.you will probably gain 3-4% power overall.

on pump gas(93 octane)i would say that 9:1 would make a little more power in the upper rpm range than 10:1,just because you can make more boost.boost=power

 

3-4% max but for the most part it seems they make the same power depending on boost. The thing to keep in mind on an 800whp car 3% is 24whp, not really the end of the world if it keeps cylinder pressure in check.

That was a 9:1 motor that made that power. It seems odd but thats how it tunes out with 10:1. I am basing this on knock voltage and then when the random knock spikes start to occur. You might be able to run a little more but it would be on the edge of issues so I feel confident saying 22psi. Obviously cams and if its a MIVEC car will go a long way to contribute how much you can run. Keeping the DCR in check with cam timing is an easy way to run more.

I prefer to run 9:1 motors just so I can go back and forth easier and still make good power on either.

Aaron