I have a 99 6spd targa car, and I am wondering about octane boosters. All I have done is a blackwing filter, Tune, Plugs and wires(stock heat range ACDelco iridium plugs), corsa catback, and a ported t-body. I live in texas and I hooked up a scanmaster that I bought to my car and am getting 950millivolt O2 reading and 3-4 degree's of timing taken out of the car. The t-body was put on after the tune and it is not tune for that mod. I was wondering if an octane booster would take away some of the detination or what ever is causing the retard in the timing. What do they really do and will they help. thanks.

 

I'd choose another gas station. Low grade fuel can cause retard timing. IMO octane boosters are a waste of money.

 

They raise your octane by about 0.1 Octane per can,,,
If you want to boost pump octane use Xylen. It has an octane rating of 117.

To determine how much it impacts octane you need to calculate ethe weighted average

weighted ocatne # = # gallons Octane 1 + # gallons Octane 2 / gallons#1 + gallons #2

1( 117) + 16 ( 93)/ 17 =94.4

 

Toluene and Xylen will KILL 02 sensors in a hurry. Or atleast this is MY experience in other vehicles.

What do you mean your getting 950mv 02 sensor readings? Is this on all 4 sensors ?

 

I was told by the maufacturer that the O2's at wide open throttle should be around 850-950 and that is the lowest average on all 4 sensors combined.

 

I think you're comparing apples to oranges here .....

The output from the 02 sensors is used by the PCM to determine wether the Air/Fuel (A/F) ratio currently being used is rich or lean, and it then adjusts the pulse width of the fuel injectors to bring the measured 02 output within a pre-programmed range.

The feedback from the 02 sensors has NOTHING to do with fuel octane. The PCM cannot determine fuel octane from the 02 sensors.

The only way the PCM can "sense" octane is from the KR sensors. If the octane is to "low" the KR sensors report the vibration caused by detonation and the PCM adjusts spark timing accordingly.

BTW ... if your "average" of all 4 sensors is 950 mv ... you are running WAY rich. Even if that measurement is at WOT ... you are probably loosing power running over rich like that. You either need to tune for that T-Body or put the stock one back on.

 

i appreciate all the help I am a novice to all of this so any help is really appreciated and Black ZO6 you have explained alot thank you. So when the scanmaster is telling me I am getting 3-4 degree's of retard is that the same as knock retard. and could weather be a factor in the retard or does it all have to do with fuel? sorry to be asking some dumb questions but it is better to ask then just be stupid. Because the days I was getting more retard were mid 90 to high 80 degree days and the car was tuned in the early spring or late winter around feb. on a mid 60 degree day.

 

There are no dumb questions ... sometimes the answers may be .. though

Spark timing is a complex issue ... the PCM takes numerous "inputs" into account to determine the spark timing .... some of the sensors it uses are ..

* Manifold Absolute pressure - MAP sensor
* Engine coolant temperature - ECT sensor
* Intake air temperature - IAT sensor
* Crankshaft position sensor (also gives RPM) - CKP sensor
* Knock - KR sensors
* Mass of Intake Air - MAF sensor
* Throttle position - TP sensor
* Vehicle speed - VSS sensor

So, as an example, at high RPM, all else being equal, the PCM will ADVANCE the spark timing more than at low RPM. Another example, at start up of a cold engine, the spark will be ADVANCED, again all else been equal, as compared to an engine at "normal" operating temperature. Guess what, on a hot day (high IAT reading), if the ECT is showing a "hot" engine, the PCM will RETARD the spark to lessen the chance of detonation.

So, weather can certainly be a factor, as can altitude, as can many other factors, in determining spark timing.

So, using an octane booster (even assuming they actually "boost" octane) would have no effect on spark timing if the RETARD is caused by factors such as hot weather and a hot engine. The ONLY way a highr octane MIGHT make a difference is if the ONLY reason for the RETARD was because the KR sensors were reporting detonantion vibrations.

HTH

 

Here in Calif we have crappy 91 octane, it is correct that the "over the counter, Pep Boys, etc" octane boosters do not work, HOWEVER, "real boosters" like Torco and a couple others do work!

I have a blown C5 and can attest first hand that Torco stopped KR on my car!

Search the Forced induction section for member jbsblownc5 (Joel) send him a PM, he is a Torco Disti and hook you up with good pricing.

RTR

 

I will enlighten people to the EASIEST, and safest way to bypass this whole damn mess.

I've been there and done: Octane Boosters. Be it: Xylene, Toluene, "over the counters", etc.

The simplest, and MOST reliable/safe is to simply fill up about 4-5 gallons of 100 octane, then top off with 91. That will get you close enough to the "93" the use in the midwest.

One must remember the "tune" in a PCM is a "best all around". Meaning 91 octane isnt exactly what it is meant for, but "close enough".

Try a blend of 100/91 and see what happens.

 

again thank you I am learning alot I appreciate it and black ZO6 thanks alot you are very knowledgable I will be hitting you up once I look at the scanmaster again.

 

This is what I do when I take the car to the track.

Here are a couple of links to help in locating sources for 100 octane UNLEADED fuel ....

http://www.rockettbrand.com/

http://www.sunocoinc.com/site/Consum...T100Locations/

 

Whoops. I left that part out. Indeed UNLEADED is important.

 

Took the words out my mouth. To be exact, for an 18.5 gal tank, you need 4.11 gal of 100 octane topping off the remainder of the tank with 91 octane to get 18.5 gal of 93 octane. Had to pull out the dusty algebra book on that one. Thats assuming the gas pump is accurate (which it aint). 100 octane over here costs $5.59/gal. It's worth every penny Good stuff

 

Don't cut corners and use shelf octane boosters. They are basically worthless for the money you dish out. Blend down racing gas in bulk and be happy as can be. 1-2 gallons of 116 octane with 12 gals of 91 will do just fine for most street cars (I use 116 straight in my Pontiac street car but its over 13:1 compression).

I just ran some Torco through the octane engines and even their claims are BS claiming to raise 91 octane to well over 100 with just 1 qt of their product. See this thread on that testing after I was looking for some to buy and use, but after testing forget it! http://forums.corvetteforum.com/show....php?t=1801944

 

briann510,

I agree with all you say about all of the "octane boosters" .... they're snake oil.

Question, the 116 octane you're mixing .... is it UNLEADED ??? Kinda doubt it, so how long do your cats survive running leaded fuel through them??

Thanks,

Steve

 

The 116 octane is leaded for my Pontiac which has no cats.

 

This doesn't compute since gasoline already contains both of these chemicals. It's like saying gasoline killed my O2 sensors...

 

Depends on the % that's mixed in.........

 

Not really, since you couldn't make use of the octane number that would be produced by an excessive mixture. Up to 30% is fine.