Highway8

iTrader: (11)

Wow you agreed with me. I saw you posted after me and I was gettign ready for an argument, JK LOL. Its all good.

nmarz77

Hey, just because we don't agree on one thing doesn't mean we can't on another.

Now, who did you vote for............

Highway8

iTrader: (11)

HAHA. I never got a chance to vote. My absentee ballet ws thrown away by my wife.

As far as the other topic, I earased it because it was pointed out that we both injected some poor and irrelevent information. I had posted a link to a very good artical, not sure if you got to read it or not.

http://www.sportcompactcarweb.com/te...t_1/index.html

It covers everything about automotive aerodynamics. I still think it would help but thats my opinion.

nmarz77

lol....I thought I had a dream about that whole thing. When I came on the next day it had vanished. Ok I will read it after I'm done screwing around on here. One website at a time....I'm an old man.

kartweb

Ding, ding, ding...we have a winner.

Also try mixing about 20% E85. Some people will shudder but I've been running that for the last 22,000 miles and no problems. That will raise the octane of 87 to 92-94.

tsxmidship

The premium shortage hes referring to was when Hurricane Ike hit. Most of the metro atlanta(as well as other metro areas in the southeast) was completely out of gas for about a week. When gas started to flow again, it was regular 87 octane for the first week or so, then mid-grade and premium started to flow in slowly afterwards. So it was about 2+ weeks where it was impossible to find premium.

chickenwafer

iTrader: (9)

You do know the stock knock sensor on the RX-8 does absolutely nothing, right? It's virtually inaudible to knock.
Not to mention one or two "major" detonation events and it's all over.

I do remember a while back in Import Tuner magazine Power Pages (where they have a scientific way of dyno testing products) they found out some octane boosters DO infact raise the octane of your fuel. The best was actually the NAWWWS brand, I believe.

It's better to source some 100 or 110 octane and mix in a gallon with a tank to provide some extra knock resistance, especially if experimenting with a new tune.

This is extra true in places like California and Arizona where we only have 91 cat ****.

04RX8man

yeah when they say it raises it a point that's not 89 to 90 it's 89 to 89.1 so 5-10 dollars a bottle to raise from 89 or 93 up .2 is not worth it at all might as well just run straight 89 or whatever

champi0n

iTrader: (1)

Kind of an old thread but i've been researching Toluene for boosting octane.

The best I can get here is 91 and I can't get rid of detonation above 5k rpm (during the summer). Winter it's not so bad, and sometimes in the winter I can run 89. (But of course, change in driving habbits during winter as well).

And I also can't put aside that carbon buildup could be contributing to increased compression.

Now it seems that anything under 40% mixture of Toluene (or probably better put, toluene "properties") should be safe for particular fuel line components, o-rings, lines, etc.. Which I would personally translate down to adding no more then 17-20% toluene per tank to compensate for existing "properties" in the existing fuel and any residual toluene left in the last few liters or last gallon of fuel from the last fill up.

So once I find a supplier for pure toluene at a decent price, I will be calculating what octane will work best in my situation to get rid of detonation. I'm thinking of starting around 94 and working my way down (if of course 94 gets rid of the detonation).

Typically you can source toluene from paint supply stores but tends to be a little expensive. (Though still substantially less expensive then over the counter octane boosters, and will yield better results).

Toluene costs anywhere from $3-$10/gallon (maybe 0.90 - 2.70/L)

Mixing 2.5 gallons (about 9.5L) of Toluene with 12.5gallons 91 octane premium should yield 94.5 octane.
2 gallons toluene (7.5L) with 14 gallons of 91 will get you 93.87
1 gallon toluene (3.78L) with 15 gallons of 91will get you 92.44

Potentially costing an extra $6-20 per fillup. (Hopefully more in the $6 range which would be what some people pay for the small bottles of "octane booster" getting only 0.2 - 0.3 boost). And we would be well within the safe limits of the amount of toluene added to the tank.

And in addition to the "octane doesn't add more power"... well.. yes and no. It's one of those lost in translation type of sayings. It adds power to engines suffering from detonation (causing timing retard) which is resulting in less power. (so higher octane gives you more power if you're engine doesn't run well on lower octane fuel). Because it's now allowing your engine to run the way it was tuned to.

But if your engine is running in tip top condition and fuel is burning properly, then octane isn't going to do anything in terms of power.

Octane just makes the fuel more stable, not more explosive.

Highway8

iTrader: (11)

Are you driving an RX8 with a rotary engine? Because if so and you are in fact getting detonation, then your motor would be toast.

Rote8

I use the CD2 lead substitute additive for the "lead" premix, my vacuum goes up about 2 inches for several tanks after I run one tank with CD2 through.
CD2 lead substitute is marketed as an octane booster.
/Catless and supercharged.

I go from 24 inches of vacuum when decelerating to 28 inches decelerating when using the CD2 premix, or for a couple of tanks after using the stuff.

Rote8

Wrong, it cuts the throttle when it senses detonation.

/If you say it does nothing, why remove it?

Highway8

iTrader: (11)

Wrong, it retards the timing, not cuts throttle. Retarding the timing will effect power but not significatly.

On a piston engine it detects minor detonation and retards the timing to prevent any major detonation that could cause engine failure.


With a rotary any detonation usually means your motor is done. So while it may do something, its too late. Thats why the knock sensor is worthless on our cars. And yes there are many people with the knock sensor disconacted, it sometimes has a false reading, retards timing and reduces the power a few HP. My motor keep going full power detonation and all.

Run the octane your car is tunned for and a little buffer to be safe. Any higher and it will cost you power, MPG and money.

champi0n

iTrader: (1)

Can someone please confirm that detonation is 100% fatal to a rotary engine, because if it was, the rotary would have died off years and years ago, and never been used in production cars.

Detonation isn't "good" because the fuel is combusting before the spark plugs were to ignite it, but it's not condition that always leads to engine failure.

I would say detonation has more wear and tear in a piston engine because its counteracting forces. (Piston still in it's upward stroke while the combustion is trying to force the downard stroke before TDC). Detonation in a rotary is not optimal, but likely not as counteractive to the rotating inertia.

And since my car still runs great in lower air temps, and hasn't "blown up"... pre-detonation in turn is not fatal. Maybe if I were to continue blasting my car at high rpm's for extended periods with detonation you could expect something to eventually give.

Huey52

iTrader: (2)

May as well add my two cents to this silly thread.

Using any higher octane then is needed to prevent pre-ignition (aka pre-detonation, knock, ping, dieseling), in your particular application, is a total waste of money. Period

champi0n

iTrader: (1)

as quoted from above.

champi0n

iTrader: (1)

interesting.

Obteene

How prone is this engine to detonation? Under what circumstances? and why did Highway8 contraDICK himself?

Gr8Bullet

iTrader: (5)

this reminds me of the time some guy put noz energy drink in his bike and thought it was octane booster

Highway8

iTrader: (11)

If your tune is bad, it will detonate and blow your motor, but with a proper tune and in NA form, it should not have any detonation. Most tunners will build some cushin into the tune, either a richer AFR or more concervitive timing.

How did I controdict myself?

I said that the knock sensor does not cut throttle and is worthless. Then I said when my motor blew, it was continued at full power dentonation and all. KNOCK SENSOR DOES NOT HELP WITH A ROTARY IN 99% of circumstances. If you run lean, or have the timing wrong or get low octane fuel, it can have detonation and almost certinly blow the motor, if you are lucky it wil be very minor and the knock sensor will retard the timing and keep it from getting worse and blowing the motor. Again if you are lucky, not likly though.

So why is the rotary still being used even with this inherent problem? Because it is tunned in such away to prevent detonation and mazda tells us to use premium fuel, even though if you run 89 or 87 you will get better MPG and more power. Basicly our engine are tunned for 87 octane but we run higher to be safe.

PhantomRX-8

iTrader: (1)

I use this:
http://torcoracefuel.net/pro-accelerator.html

Its racing fuel concentrate that actually does add octane to premium fuel. I used it in my Saturn Redline blended to 97 octane and the car loved it. I ran 32* total timing on a supercharged engine with 19lbs of boost. I will be running this in the 8 when I get the car fully running again. Stuff is amazing, highly recommend it.