Octane booster Question

[rn240sx]

Ok, here is my question and concerns:I currently run a turbonetics T3/T04E, 370cc inj, jwt ecu and stock maf. Im only running 8 psi due to fuel limitations.I wana push it up to 10 psi, but the only way i see this happening is to either upgrade my fuel system, OR, Put in some higher octane.Here locally the highest avail is 93 octane. I was thinking of filling up the tank with the usuall 93 octane and then adding some octane booster which is like 108 or something, which i can find at my local auto parts store. If i were to add a bottle or 2 of this octane booster to my full tank of 93 octane, what should my octane rating increase to..?? Of course im not looking for an EXACT # but an guestimation...I was told it should bring it up to at least 100 octane...

Hell, I hit 10 psi one time to race a 400hp camaro and the motor held fine.. BUT i did notice that it started to lean out as the rpm's were climbing in 4th gear... OR the timming was getting thrown off to trick the EGT probe....

What do u guys think..?? Im safe right..??

ThanksRobert

[MarkEmark]

2 bottles of 108 won't come close to making your effective octane 100. 108 octane an those boosters will boost octane eight points , so you'd have like 93.8 octane.

If you want a real octane boost, go to a paint store like sherwin williams and use Toluene....there's a bunch of info about it on the web concerning how much you should use an what the effective increase in octane is, but I'm too lazy to search for them myself.

[cow]

Mark is right, that stuff won't do you any good. Off the shelf "Sport Compact Octane Boosterz!!@#$ Import t00ner JDM!!!" are a complete waste of money. Toluene is the bomb, and most people don't seem to know about it.

It's pretty easy to figure out your octane rating..just divide the number of total gallons of 93 and those with toluene by your total gallons. Does that make any sense? heh

So say you have 13 gallons of 93 and 1 gallon of toluene:

((13*93)+(114))/14=94.5 octane

For 100 octane you'd need about 35% toluene. S14's have a 14(?) gallon tank so say 9 and 5:

((9*93)+(5*114))/14=100.5

You can also find race gas at some gas stations. I know a couple places around here have 110. :o

[cow]

Oh yeah, ha, I just re read your post.. if you are maxing out your injectors it won't matter what octane you're running, you won't make any power and you'll still risk blowing the motor.

On a T04 I'd imagine you will be pushing your luck at 10 lbs.. 8 or 9 is usually the limit on 370's.

[WDRacing]

Try using 5 gal toluene for every 10 gal of 93...should yield about 108 octane.

[DriFt3r]

I've found some 110 octane race gases at the local station, but it seems that the 110 gas was LEADED. Can we use leaded gas in our unleaded engines?

[C-Kwik]

not with a catalytic converter. lead destroys a cat very quickly.

[rn240sx]

To COW:You wrote: Oh yeah, ha, I just re read your post.. if you are maxing out your injectors it won't matter what octane you're running, you won't make any power and you'll still risk blowing the motor.

On a T04 I'd imagine you will be pushing your luck at 10 lbs.. 8 or 9 is usually the limit on 370's

To be honest, I purchased my turbo from Turbonetics exactly one year ago. This was the turbo that was being used on the Fmax stage 1 turbo kit for our 240sx...If I recall looking back on "fmax's" actual site when they were still running as Fmax. their page said T3/T4... When I go to Turbo kits.com it shows a T3/T04E and he claims this "T3/T04E" has always been the turbo that they used for the 240sx turbo kit. Now my contact was Adrian at fmax but he is no longer there. I have called back 4 times and spoke to several "techs" and they seem to have no recall of what size turbo they USED or what size they are USING for the 240sx...I can tell you that its a .48 a/r with a stage 3 exhaust wheel. Thats the exact spec Adrian gave me when I called him the 1st time to ask about the turbo they used for the 240sx.. But i didnt ask him about the compressor size..

If there is anyone out there that has purchased this fmax kit last year in March or so and can VOUCH for what size turbo they have providing that they didnt get an upgrade... This might help me out here. Im running 370cc inj and i may or may not be maxing them out at 8 psi...

Another thing, even if the injectors WERE maxed out at 8 psi, and i went up to 10, im still dumping higher than usuall octane in the cylinder, so that alone should hold compensate for the extra 2 psi of air im adding....Correct me if im wrong...

ThanksRobert

[Jeff240sx]

Another thing, even if the injectors WERE maxed out at 8 psi, and i went up to 10, im still dumping higher than usuall octane in the cylinder, so that alone should hold compensate for the extra 2 psi of air im adding....Correct me if im wrong...

ThanksRobert

You're wrong, like so many people have stated before. Octane resists detonation that is caused by heat, timing, compression, ect. Your lack of fuel will not be compensated by octane. Race gas and octane aren't the miracle workers. You hear people saying "I run 20psi normally, and 25-26psi on race gas" because although they have the fuel (usually 72# injectors), thier setup will cause detonation at 25psi, but is good on 20. So they fill up with race gas, which resists the detonation, and they can run more virtual compression (boost), and cope with the additional heat and keep the same timing. Octane simply makes gas harder to ignite. It won't act like more fuel, or prevent you from blowing when you don't have the needed fuel.-Jeff

[rn240sx]

I kinda see your point there..!! But its still a little coudy..

We had a local guy here with a fully built ka-t was pushing 21 psi fine on pump gas... BUT when he went to 25 or more he started to detonate and blow head gaskets left and right. SO he had to use race gas to hit 25+psi...

But it seems funny how lots of turbo shops will say if ur maxed out on the injectors, just run higher octane 100+, then your allowed to add a couple more pounds..... simply because of the higher octane, that it will prevent the detonation...

[cow]

Quote »But it seems funny how lots of turbo shops will say if ur maxed out on the injectors, just run higher octane 100+[/quote]If a "turbo shop" is telling you that I would stay far away from them for any sort of engine tuning advice.

It's simple: you HAVE to have sufficient fuel for a given amount of air. If your injectors are maxed out at 100% duty cycle, the only way you will get any more out of them is by raising the fuel pressure significantly, and this won't get you much further. Raising octane will not give you any more fuel for the extra air you are adding, period.

If you do in fact have a .48 a/r turbine, you might be ok to 9 lbs. Maybe even 10 lbs.. but why push it? The little gained power is not worth the risk of blowing your motor. Get some sort of computer that can monitor your injector duty cycle and find out where you are at redline at 8 lbs. That will give you a definite idea of how much room you have for error.

[rn240sx]

Well I just got an email back from a buddy of mine who has the opposite theory...1: well, octane burns slower2: so you can run it leaner without the gas detonating3: you can go leaner because with 100 you can run like 14-1 A/F ratio's4: where as normally you should be at like 12-15: so that means for the same amount of fuel you can pump in more air

That was a quick explanation of what he gave me.

Im not saying your wrong cause i am obviously not an expert here. And im not here to offend you in any way. But you are the ONLY person to tell me that i cannot substitute higher octane if i have no way of adding more fuel...

Its really not that important cause im upgrading my fuel system in 2 months anyway, i was just curious...Im gonna go ahead and end this discussion here, cause it will probably just continue with what u said vs what they tell me...I appreciate your input and i do understand your point..!!

Take care..

[Jeff240sx]

Well I just got an email back from a buddy of mine who has the opposite theory...1: well, octane burns slower2: so you can run it leaner without the gas detonating3: you can go leaner because with 100 you can run like 14-1 A/F ratio's4: where as normally you should be at like 12-15: so that means for the same amount of fuel you can pump in more air

He's right.. to a point. There is no way to tell, without dyno results, to say that "100 octane will let me run 10psi." And I really think that the ammount of boost you could actually add would be virtually nothing. As I said before, when people have 72# injectors, they have enough fuel (using the BSFC formula) for 450hp. For 450hp, a KA-T would need 25psi or so. The thing is.. with a smaller turbo, you run out of efficiency up there, so you create more heat per extra psi you squeeze out. Then the FMIC can only cool so much air at a certain efficiency. This is where race gas comes in. The injectors can handle the boost at 25psi, and the hp, but the air is super compressed in the cylinder, and the heat from the compression, and running out of efficiency on the turbo will make the gasoline detonate before you want it to. Race gas prevents the detonation. It's not that it allowed for more power directly (it is not acting like more gas). It simply prevented detonation, which in turn allows more boost. The injectors comfortably handle that power... it's the gas that didn't.Race gas you can turn the timing up some (our ECU retards the timing when using lower octane, or making boost enough to cause a knock.) Leaving all else alone, advancing the timing from race gas will allow more power. Also, you can lean it out and create more power.370cc injectors (35#) are good to 260-280hp, depending on tuning. If you are making 260hp at 8psi, you'd make 280-290hp at 10psi. Without great tuning, you won't be able to handle this power for prolonged periods.. because you are causing detonation. Not from heat or compression, but due to lack of fuel. A pound of boost is really alot of air to add fuel to, and alot of power (10hp, or more in some setups). So while race gas may handle 5-10hp (as I said, usually from timing advancements), it won't handle the 20hp+ from more boost that you'd need while lacking the fuel for it. So yea, it'll help, but there isn't a way to precisely determine how much more boost or power you can run simply by adding 100 octane, without a dyno. Cliffs Notes: Race gas helps. You can't tell how much without a trip to the dyno. I wouldn't try upping 2psi of boost on race gas without an accurate A/F reading (GReddy a/f gauge, wideband, dyno), because you are at the limit of power 370cc injectors can handle. -Jeff

[rn240sx]

Well, your entire story there completely explained it to me and makes so much more sense. Well, i was going to upgrade my fuel system anyway... I was just curious to know if that rumor was true and if it IS or ISNT recommended...

I guess i will have to throw it on the dyno and see what the actual a/f is to see if i have room for more boost...Suppositly the jwt ecu runs very rich so i may be lucky to squeeze in 1-2 pounds more...

Thanks for all u guys that replied...!!!

Robert

[burnin240sx]

just curious on how much your jwt retune cost.

[Jeff240sx]

JWT ecu programming list price is $595. JWT list for a retune is $125.If you search around, you can save like $5 on the retune and $30 or so on the initial program.-Jeff

[burnin240sx]

so u have to have get a jct ecu and then the future retures are 125?

[WDRacing]

That is basicly correct...