race gas question?

[pclear9061]

i just found out it is 4 bucks a gallon at the raceway if i wanted to get 100 octane and 6 bucks a gallon for 110.

what do yall think we can run up to and where do yall think it would stop helping? (octane level)

also im prob gonna be getting the 3" pulley and spark plugs not from psifi tho and will this help, not effect or what?

ya know what im getting at?

[dam718]

It may very well benefit you none at all...

You may see no benefit from 93 octane...

If you do a few google searches on octane ratings you can find some interesting articles relating to octane ratings and what it really means regarding performance.

The higher the octane rating, the slower the fuel burns off, creating a simulated increase in compression because the gasses do not ignite until the piston has compressed the gas a bit more creating a higher temp, etc... Do you NEED higher octane? Most likely not unless you experiencing bad knock, then ramp up the octane a bit...

I'm not too educated on the subject, but that's the basic jist of it.

There are a few engines out there that are extremely built up (higher valve lift cam lobes / stiffer valve springs / bored over cylinders / etc...) that really do NEED higher octane fuel, but we do not... Not yet anyway

[mailmars]

Originally Posted by dam718

It may very well benefit you none at all...

You may see no benefit from 93 octane...

If you do a few google searches on octane ratings you can find some interesting articles relating to octane ratings and what it really means regarding performance.

The higher the octane rating, the slower the fuel burns off, creating a simulated increase in compression because the gasses do not ignite until the piston has compressed the gas a bit more creating a higher temp, etc... Do you NEED higher octane? Most likely not unless you experiencing bad knock, then ramp up the octane a bit...

I'm not too educated on the subject, but that's the basic jist of it.

There are a few engines out there that are extremely built up (higher valve lift cam lobes / stiffer valve springs / bored over cylinders / etc...) that really do NEED higher octane fuel, but we do not... Not yet anyway

I think Sp00ner (or maybe Goofy) looked into this and stated that the PCM does pull timing with 87 octane because of knock detection. I believe he said that it appears the tune is for somewhere around 89 octane....

Mark

[dam718]

And regarding the plugs... Read this article from NGK on "reading" plugs.

http://www.ngksparkplugs.com/techinf...200&country=US

Don't forget to click the link to examples of common problems effecting the firing end of the plug.

Also, check out this, also on the NGK site which is a tech tip on exactly what the function of a spark plug is. I reccomend this to everyone.

http://www.ngksparkplugs.com/techinf...000&country=US

Do not just "willy nilly" change anything about your plugs without knowing what they do, and how to check and see if you're having problems.

Being able to "read" a spark plug can save your engine, and in turn save your wallet...

There is a ton of other good stuff on the NGK site as well under "Tech Info" regarding spark plugs... I know I have learned quite a bit from there...

[Aeain]

Here in Ohio Sunoco sells 94. I'm switching to it over the winter and see if it helps with winter performance. I need to fill up a few more times and see what happens. Right now it's just running a little bit richer, and that's with Half a tank of BP 93 and Half a tank of 94.

[dam718]

Originally Posted by mailmars

I think Sp00ner (or maybe Goofy) looked into this and stated that the PCM does pull timing with 87 octane because of knock detection. I believe he said that it appears the tune is for somewhere around 89 octane....

Mark

If that's true that the knock sensor is picking up ping with 87 and retarding the timing to compensate then 89 / 93 is probably the way to go... Keep in mind, however, that there is no performance difference when you go higher than you need.

The amount that you "need" is commensurate to the amount the knock sensor retards the timing based on noticable ping. If you get no ping with 89, then there is no reason to go higher. An engine only gives a shit about octane when you don't give it enough. Higher than it needs makes no difference at all and neither helps or decreases performance.

FOr those that have the Interceptors or any other ODBII scanner that can actively monitor the knock sensor and engine timing retard / advance, I'd be interested to see if 89 is all we need... Gas is getting pretty expensive... I've been running 93 since I bought the car just to play it safe...

[Blu_Redline]

I run BP 93 all of the time. Every once and a while I will get some Sunoco 94 and put it in if I am going to the drags. Truthfully, I see & feel no difference. The interceptor shows no knock at all with 93 in the system. I have to put the car in 3rd and stomp on it at 20 MPH to get a momentary knock and then the ECU immediately retards the timing to get rid of it. I tried SUNOCO 100 unleaded race gas once at $6.00 a gallon. No different times than the 94, but it smelled real good!!!!! High/Low octane will show up on a high speed run. with 87 in the tank, my ECU cut the engine off @ 127 mph while 93 octane allowed me to get to 140+. ( I backed off, could have gone higher) High octane race gas isn't really needed until you have a static compression of 11.5:1 and higher, or a 9.5:1 static engine running lots of boost (over 20 psi)

[SilverBulletRL]

I put 110 in mine at the track last time we were there... the car LOVED it.

[yianco465]

So does running 87 or maybe 89 will get you less HP than 93 or does it just affect top speed limit. I've read from different manufactures that they quote some minimal loss in HP when running regular in a car designed to run on premium

[Blu_Redline]

Originally Posted by dam718

FOr those that have the Interceptors or any other ODBII scanner that can actively monitor the knock sensor and engine timing retard / advance, I'd be interested to see if 89 is all we need... Gas is getting pretty expensive... I've been running 93 since I bought the car just to play it safe...

The car will not knock to speak of, the ECU immediately retards the timing to get rid of the knock. You only lose performance (just like the manual says) by running regular unleaded. I can be cruising along with 35° of timing and hit the gas pedal and it will drop to 20° of timing to eliminate any spark knock. Then as the load decreases, the ECU increases the degree of timing advance.

Modern engines are not at all like the old static timed ones of yesterday.
My 55 chevy had a 302 that ran 38° with an ACCEL LAZER ignition and in no way did it ever get as low as 20° of timing. Of course, when I put a load on the engine at low speeds, it knocked like a coffee can full of marbles. Times are different and computer controlled engines are great. My ION red line runs as fast in the 1/4 as that 55 Chevy did with a 302 Z/28 engine, 4 speed & 411 gears. (14.50s) and gets 29 MPG, where the 55 was lucky to get 12 mpg at best.