I am curious to see what compression you all are daily driving your cars on, i was thinking no more then 12.5.1 would be practical on pump due to the amount of timing you would have to pull after that compression to still run pump would defeat the purpose past that point. so how long have you been driving the car and whats your compression?

 

+1, I'm interested in this too

 

You're about right. For B-series engines about 12.5:1 compression is the limit for 93 octane gas. Not sure about the 91 "water" that a few states have to deal with. As you stated, even those running this compression on 91 water have to reduce timing in a manner that it defeats the purpose of even being at that compression ratio.

The number of years of use for "daily driven" is irrelevant if you don't factor in the correct build of the engine and the tune associated with it.

 

in CA we run 91 octane as our premium and most people dont go over 11.5:1 using this gasoline. but there are folks using up to 12:1 on this shitty premium gas we are stuck with.

 

11.5:1 is considered by many tuners to be the "ideal" compression for the street as it allows you to run pump gas without issues and an aggressive amount of timing which will help make power. Compression isn't everything when it comes to making power....balance and good part selection are far more important.

 

Im running 12:1 in my B16 on 94 pump gas, we here in Canada are lucky enough to get it

Car runs great as a daily sees 9k everyday. Motor has just over 10,000 kms on it now and will be going back to the dyno soon for some more tuning. We can get a little aggressive with the timing but nothing too nuts

 

Not all parts of Canada unfortunately...lol 91 is most here in the East.

How did you calculate your compression ratio out to be 12:1, just curious.

 

i should be somewhere around 10.9:1-11:1 or at the very least 10.7:1

 

Yes ofcourse Im refering to an excellent tune, paired with a good build when i mention this topic.

 

What about 13.1:1 CR DD b20V on e85...?

 

Let's keep this on topic, were talking pump gas here.

 

That sucks, didnt know you guys dont get 94 over there.

11.5:1 Mahle pistons, flat faced valves and slight head milling, puts me at 12:1 C/R and 270psi in each cylinder during a compression test

 

12.2:1 here, I don't daily drive it anymore though. When I did drive it, it never had a problem.

 

im runing 12.5 at 85mm on 91 oct. in my DD with AC. no problems
but it was tuned on 91. gsr block and gsr head...

 

Keep em coming guys

 

You love it when guys keep on cumin homo

 

on 85mm bores if you start with a flatter piston style you could run up to 13.1~4ish :1 if you weld your chambers or mill the hell out the head to make your chambers real small.

 

i can drive down the road and pump e85, so how is it "off topic"?

 

ran 12.3:1 for 70k miles on my sohc vtec before i parted it out...several years, but i can't remember the exact number. tuned by jeff evans with an apexi power fc. bkr7e-11 plugs. this was during the time when 94 octane was available at sunoco. after that disappeared i stuck with shell 93.

 

I'm on pump gas with 13.0CR....it is on topic..

You can run 11.5 CR on 89 oct gas.. its in the tune.. stay on topic.


On a 13.0CR ls/vtec you really wouldn't have to pull timing.. you can run stock p30 ign maps(which are the most aggressive stock ign maps) and be fine.
The "ONLY" reason i pulled a few degrees out on the low end of my motor is because its still stock sleeved..b20 sleeves are only known to crack sololy based upon low end/high load knock.
I pulled out about 2.5 degrees between 1500-3000 in the area in which it knocked, it wasn't max mbar but it was around the 4th from last column...I'm pretty aggressive throughout the rest entire map.

I just tuned a car running 13.5 on pump gas, i wouldn't recommend me to anyone going above 13.0 on pump gas, hell i wouldn't recommend anything above 12.5CR on pump gas.. however.. its been proven and safely proven you can run high compression on pump gas if your tune is done correctly..


EI and i learned this a few months back and its pretty hard hit.. stations that sell gasoline with E10 or 10% ethenol have shown to have anywhere from a 2-4 point drop in octane rating, this is only if it has a water seperation phase.

 

12.7 ctr piston in b16b with gsr rods and crank, no problems

run 93 octane with ngk 7s.

timing is slightly lower than i would like, but i run race gas at the track and switch maps

 

Go to 8's, run .035 and run the more aggressive ign.

 

wonder what our honda b,k,h vtecs would run like on natural gas,the civic gx series make the same power as any d series by bumping comp as natural gas allows that.

I wonder if a b16 with 14 comp on natural gas would be worth it at all? this is what happens when you pay over 6 bucks a gallon for fuel here in Germany,you start looking for alternatives.

 

really? explain, im curious to know

I didnt even run 8s in my setup listed

 

Run it and throw that hoe on e85