few octane questions

[kingkill83]

Ok, here we go. a few questions

check my mods below for further intel (in my sig)

got msd finally, the coils, and plugs, running accel plugs.

gapped slightlly hotter.

straight piped, minus muffler.

now to the questions. when cat was eliminated, rear 02 sensor code triggered check engine. to eliminate i got mil eliminator coming my way. now, with this code, does it cause the pcm to make the engine run limp/lean. what improvements am i looking at for the mil eliminator?

will this cause me to be able to get passed my 120 top speed once more? before i eliminated the cat i could go about 140 easily, and now im limited at 120. is it due to the rear code causing me to run limp, or is it due to my bodykit catching wind?

also, with the msd system, i notice gains slightly running 93 octane on fill up, with 110 octane (usually 1 or two gallons).

however, im wondering how much the engine can take of 110?

honestlly, its fun as hell, i pull on my buddies 87 monte ss when second gear hits. its funny watchign his face as i pass him. before flaming starts, he is running slightly rich, and has 20's on his car rim wise. lol. its not built but he is claiming 305 whp, i wonder what his limits are whp wise with those on there?

i know the msd helps it burn better, as i end up with spark knock running les then 93 octane now. >.<

i mean i love the msd but its more expensive to run the set up now.

anyhow, on to answers. look forward to them, as i cannot for the love of all that is holy find anywhere how high octane our engines can handle. whats the max without issues?

[Jchiasson]

running accel plugs.ACDelcos are recommended.

gapped slightlly hotter. You cannot gap a plug to be hotter. Not to mention the fact that when putting mods in to a vehicle, and you want to change the "temp" of the plugs you should go colder. Hotter plugs are for old ladies who never get up to operating temps in the engines. Helps burn the fuel more completely.
straight piped, minus muffler.
So your running straight pipr from manifolds to bumper?
with this code, does it cause the pcm to make the engine run limp/lean. what improvements am i looking at for the mil eliminator?.No it does not make the engine run limp/lean, you will see no improvements. The rear O2 sensor simply tells the computer wether your CAT is doing it's job or not.

will this cause me to be able to get passed my 120 top speed once more? No and not sure why your governer has dropped, possible that the lack of back pressure the vehicle thinks it's doing 140 (just a guess)
however, im wondering how much the engine can take of 110? You'll know when something goes wrong.

[kingkill83]

Q.-ish ACDelcos are recommended.

A.yes, but accel is a better plug by far when upgrading the ignition systems. only other thing i would think of would be to run ac plat plus, and those are way too much for what they do- which is the same as accel. the reason i gapped them hotter is to burn up all the fuel better running the 110 and the premium, as well as to get the full ignite capabilities out of the coils, and the actual voltage produced by them and the 8.5 mm wires. not to mention to help burn up carbon before it hits exhaust with no cat. ^.^

Q.So your running straight pipe from manifolds to bumper?

A.thats correct. however, i was told that check engine light is signalling a lack of the amp range from the rear 02 sensor and when it goes, it causes the engine to run in limp mode because of emission laws? so i heard wrong?

more: well, the theory was the governor hasnt dropped as rpm range is still well there, i think its the air catching the rear bumper. i only have the front and rears on, and they are wider, and not painted. so when i go excess of 110, my buddy behind me says the rear bumper edges are flapping like wings. im thinking after i get the side skirts on and painted, with the rest of the kit it will
a. harden the body kit from flapping as it is polyurethane mixed with fiberglass
and
b. cause the aire to not catch as much in the rear due to the side skirts also sitting out a little bit wider as well.

thats jsut my bodykit theory. especially in theroy stronger if it isnt running limp?

so the mil eliminator will do nothign but cause my check engine light not to come on?

[Jchiasson]

the reason i gapped them hotter You can not gap a plug hotter! Gapping a plug does nothing more than make your coils need more or less energy to jump the gap.
http://www.dansmc.com/sparkplugs1.htm
The heat range of a spark plug is controled by the length of the center electrode. A longer one is hotter because it takes longer for the heat to flow through it to the cylinder head. As you might think the cooler plug has a short center electrode. The plug must keep a temperature of, between 752 and 1652 degrees Fahrenheit. If it gets too hot it can fire off the air/fuel mixture at the wrong time. This can cause detonation and/or pinging which will put a hole in your piston... not good. If it gets too cold it will not burn off the carbon and fuel deposits on it's tip and the plug will foul out (stop working) not good either.

is to burn up all the fuel betterSPark plugs merely ignite the fuel, they do not burn the fuel. Characteristics of how fuel is burned is strictly governed by the fuel used, and the air/fuel ratio.
amp range from the rear 02 sensor and when it goes, it causes the engine to run in limp mode because of emission laws? so i heard wrong? What the hec is amp range of an O2 sensor? You heard wrong. At least for our GAs.
thats jsut my bodykit theory. Definitly get that tightened up!
so the mil eliminator will do nothign but cause my check engine light not to come on?Correct.

[Ralph]

Platinum Plus plugs are what came in our car and has been proven many times out perform most other plugs by far spend the extra 2 bucks or so a plug and do it right.

[kingkill83]

well its good to know i was being fed bullshit by the info on plugs....

as far as the 02 sensor goes however, it has an output voltage that is read to it by the exhaust mixture in the cat from what i was told, and when it trips its because the air is going through faster and causes it to have a different voltage output signal back to the pcm.

well atleast it was only 14 bucks for one to get rid of that gay ass check engine light hehe.

on the rear 02,
OBDII cars have two oxygen sensors to measure the amount of oxygen contained in the exhaust gas. The first sensor is located on the manifold or header and measures O2 content of the exhaust as it escapes from the cylinders. This sensor is used by the PCM/ECM to calculate fuel trims and look for combustion problems. The second oxygen sensor is located after the catalytic converter and is used only to measure catalytic?converter efficiency. The PCM/ECM does NOT use any data from the secondary O2 sensor for engine management. The PCM will set an CEL(check engine light)/SES (service engine soon) / MIL(Malfunction Indicator Lamp) light?if the catalytic converter is removed, the sensor is removed, or the sensor goes bad.

so it is correct and will only reset the check engine light. still lack of annoying light, well worth it imo.


yea i need to turn around and get the kit painted but beign in lawschool and only working at autozone puts a dampener on funds hehe.

[kingkill83]

now that the 02 sensor issue and the spark issue is understood, does anyone know the max octance rating our engines can handle before we start burning out our seals and piston rings? i still cannot find this information anywhere, and i would like to know. does anyone have any link to gm powertrain?

[gt00]

now that the 02 sensor issue and the spark issue is understood, does anyone know the max octance rating our engines can handle before we start burning out our seals and piston rings? i still cannot find this information anywhere, and i would like to know.Higher octane will not give you any extra power on it's own . Using an octane rating higher than your engine needs is just a wast of money $$

Octane (http://en.wikipedia.org/wiki/Octane_rating)