Thread: sr20ve and best gas grade

This. Lower octane burns easier then higher octane. I'm tempted to run 87 in my VE, but I'm going to be going back to turbo soon enough thus it's not worth adding 87 to the tank that has only seen 93 for the last year.

Also this is in the turbo section since it's more relevant for boosted cars, but neverless a good read for all: http://www.sr20-forum.com/turbo/4102-what-octane-does.html





Octane boosters are useless, read the label, it barely raises the octane.

I had to do this on a couple of different occasions when I had my RR DE w/ advanced timing (18*) and had no problems. I was out in the country and the gas stations either only had 87 or had run out of the premium, I can't remember. I put two bottles of octane booster in. Two bottles will have minimal gains over 1 bottle but I did it for peace of mind. Ther have been lots of studies on octane boosters and manufacturers claims of raising the AKI levels 5-7 points. From what I remember many were tested and the worst ones did nothing or even lowered the octane rating and even the best ones only raised the level by 3 points. Some of the boosters only raised AKI levels by 1 or 2 points. These tests were done on 87 RON gas and showed fewer benefits on higher grade gasoline.

Even if you could get a good additive that could bring you up the desired 3-5 points, it wouldn't be cost effective. Plus, some of the fillers in the "boosters" which are heavy solvents can harm your car with prolonged use.

Would be cheaper all around to just use premium or whatever your car is tuned for.

And as far as using 100 octane on a stockish VE...waste of money. You will see ZERO gains with using a fuel that is rated above what the tune on your car requires. Fuel doesn't "make" power. It allows the car to be tuned to the limits of the fuel it has in it.

ok ive read the thread

ok now im confused, so what if I have 14:1 compression on an NA VE,with n1 cams what octane should I run for max power?

only fuel we have here is 93, 95, 98 and 100

I put in between 91 and 93. Me neighbor puts in 87 with dollar store octane boosters and thinks he's getting over 90 octane. I guess he likes lying to himself.

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Why is a 100 octane a waste aside from what it costs? Can't you pull more timing thus possibly increasing some more ponies on it?

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Its a slower burn and actually requires more energy to burn. If u just run a higher octane you will loose big whp. After tuning you can gain some back but from my experience over 93 is a waste.

Even on my SR 16 piston sr20 I made 1 more whp with 100 octane after completely re tuning fuel and timing maps.....

The big key is if your knock limited then yes higher octane will help. If not its a waste.

I think Cory answered it better than I ever could. But just to add, you could theoretically just keep increasing timing, but I believe that once you advance the timing too much you start to lose power, especially up top. I am no tuning expert at all but I think some of the guys on this froum have experimented with the timing in the high RPM range and discovered that they saw better results when they pulled timing from wherever they had it previously. I am sure I probably oversimplified this though. Somebody correct me if I'm wrong...

Yes once you advance to far you will loose power

I'm running 14+ CR and I'm running e85 because its at the pump and under $3 a gallon. This is around 112octane. I think 110 would also do the job well.you could probably mix regular and 110 to get something to work even better for you. But you'd have to try and test it on the dyno. The more regular you add you'll see your afrs drop.



I'd start with 100 and start adding 87 or whatever you have and keep track. Find out what works best. Or maybe even easier the other way. Start with 95 and slowly work your way up until you can add enough timing for power to level off without knock. But if your using more octane then you need to do this you'll likely be leaving some power on the table.might not be much. But still with a set up like that I'm sure your trying to get every last bit out of the car.