Sounds like an exhaust leak...

 

how bad do you think a stage 2 cobalt would run on 101 octane with a gm stage 2 tune

 

i agree..

but seeing how people want more power and all i see is people going smaller on pulleys.. then people need to stop going for cheap fixes...

like these diamond pistons with 10.5:1 compression which is higher then us stock??!!? are you ******* kidding me.. drop the compression not up it

 

Good post! That stuff does work, and so does Turbo108 in the big metal can, and Turbo108 is cheaper by a couple bucks.

I think you will see a great reduction in knock if you made a dualpass intercooler plate and ported out the blower opening (The big triangle part), no to mention you will get a lot more CFM through that blower, but be sure to retune your MAf and VE after that. No doubt your knock is coming from heat, so try and eliminate that and it will pay off in the end, no need for the octane boosters all the time.

agreed, my exhaust manifold leaks too and it ticks like crazy, either try tightening the bolts, or your cracked the manifold or blew the gasket.

 

Oh i completely agree. but im talking more about people who are not "ZOMG I NEED MORE PAWAHHH" and just have a few light mods....dont know a whole lot about internals....maybe have a tiny bit of knock.

for those people, a bit of octane and some cold plugs are ideal.

 

Well the article that HOT ROD magizine did a few years ago said that even the best octaine booster stuff on the market only gave you at most 1 to maybe 2 points raise. Their expert engine builders were all saying the stuff is a bandaid fix for a more serious issue. Sorry guys but I'll take my engine building advice from someone whos been around since the 50's before that of local tuner buddies. All engines work the same regardless of old school or the highest tech ones.

The "bandaid" label wasn't ment as a knock agaisnt his car its just that somethings not exactly right and he should concentrait on fixing the problem rather then look for a quick fix.

Not trying to sound like an ass hat guys really I'm not. I've had boosted cars before, I've delt with spark knock and I've seen what happens to the engines when its not fixed correctly. I had to replace several pistons cause I thought octaine booster was working and I ignored the advice of experts even after I sought their help with the knock. Just be careful is all I'm saying.

BTW I was running 25 pounds of boost into my V-8 turbo Trans-Am back 20 plus years ago so I know a little about how it works.

Good luck.

 

Jackalope- Can you please explain to me how your pistons are being "hurt" if you have no knock. I mean its not a cover up it actually is not having knock anymore, I mean in all reality I could have my tuner come back up here and turn timing down some, but I would rather save the 75.00 for him and 100.00 for a dyno and just put a bottle in whenever I am ready to run. Also the gm stage 3 kit allows for 100 octane on stock pistons so I'm not sure how the pistons are being hurt here. Like you said not trying to argue, but I would like to know how you figure the pistons would go bad?

 

jsut got back from tag and did some street tuning with mase,
he bumped the timing a tad in 4th and it knocked ever so slightly around 5 grand then dropped, we will complete the street tuning when i get my areoforce gauges and lc1 so we can add or take some fuel where need bee, thinking about trying this product

 

I have used another brand of octane booster, I think it also helped with eliminating knock during nitrous dyno pulls...

 

And one more to add to the list of fixed cars.

 

octane booster IS a bandaid...


if you have knock on a particular pulley... either your tune isnt right... or the pulley is too small.


for the particular mods on the car... the KR should be at 0. If not... octane booster is ONLY A BANDAID, since it should be running no KR.. or stoich.

 

My god this was a painful read. engine knock. here is what it is....

timing is everything for proper engine performance. the engine has a air fuel charge that is to start burning with the spark of the spark plug. this has to be timed perfectly for max power. how do you get max power?

the charge has to be ignited to go off "Like a bomb" (controlled ignition) to fire the piston down. It must be done when the piston is just over TDC (top dead center) which is the point of the piston is done traveling up and just before coming down. if the charge is fired too long after TDC then you will lack power.

IF THE CHARGE IS IGNITED BEFORE TDC YOU GET KNOCK. this is the confusing part. Fuel is ignited in two ways. a spark (spark plug) or compression. Have you owned a car that would "diesel" after you shut it off. that is because the car is igniting fuel with just a hot motor and compression of the air fuel charge. no spark needed. so heat plays a role too.

lets review - timing, compression, and heat cause the fuel charge to ignite. Knock is when the air/fuel charge ignition occurs before the piston reachs past TDC.

Timing - at a said RPM timing maybe good at a 1 degree. meaning fire the plug +1 degree before TDC. the air fuel charge takes time to burn to have our controlled explosion. but as the engine rpms increase the fuel charge to burn does not increase. to counter act this advance the timing to +10 ignites the air fuel charge sooner to allow the burn to happen at optimum time, just past TDC.

so what could screw this up? Timing - do much timing or advance timing. Fuel - octane allows fuel to be more stable and refuse to burn under pressure and heat. Compression - as boost increases so does compression of the gasses. Heat - heat generated from the supercharger and not being cooled off will cause premature ignition as well.

what can fix it? safety mechanism in the motor - Knock retard - senses knock and retards the timing so it is not igniting the air fuel charge before the piston has time to get past TDC. Octane - resists heat and compression ignition. Compression - limit boost to be safe with fuels not high in compression. Heat - provide proper cooling to keep intake temps down. use heat exchanger, dual pass intercooler mode, Water/meth.

bottom line what does this all mean. Use what ever means to allow proper timing of the air fuel charge to be ignited. that may need to be a combination of methods but Octane maybe the last resort IMO. but there is no real wrong way to deal with it, just better ways.

Hope that helps clear up some discussions.

Bottom line - have cool intake temps and timing spot on first. Boost is to increase power levels so you will need to have a plan to balance that out with cooling air temps. Octane is not wrong, just maynot be necessary.

Good luck all.

 

Sure, no problem. The octain booster does not mix uniformly with your tank of gas also its NOT the same stuff oil refiners use while they mix the gas its llike you said an aditive.
HOT ROD's test showed that thee best you could get was 1 to 2 points worth of increase which isn't a whole lot. All your doing is quieting the spark knock down to a level that its not as aparent but its still there. Boosted cars are very finicky when it comes to A/F ratio and where throwing in higher octain fuel does help the problem it does not eliminate it. All
it does is slow down the burn rate of the fuel in the cylinder reducing the knock. The only way to get rid of the knock is with a proper tune which addresses A/F ratios and spark timing. You could probly eliminate all your need for this booster stuff by just pulling a couple degrees of timing out. Now true more timing = more HP but thats up until the knock starts THEN the HP drops like a brick in a bath tub. You need to find that happy medium where you make lots of power without the knock.

 

^^^ hit it on the head.

 

Hmmmm...... I guess that is why it is called timing..... spark at the right time.... not late and not to early..... LOL. this solidfies my point that Octane is the last thing to do before anything else. As for how Octane booster mixes in the gas tank and Hot Rod's test I was not aware of that info. thanks. and it makes sense. Great!!

 

^ ^ ^ You guys are absolutly more then welcome! I've been building cars and engine and yes even serious race engines for almost 20 years now heck I've even done a few boats too, had 2 cars in HOT ROD magizine and helped design the swap kit for installing small block Chevy engines into Fox body Mustangs and Capri's. I've blown up more engines then most of you have even ever seen LOL! Hell I even had Joe Mondelo (The Oldsmobile guy) as a friend for a little bit years ago. I was an ASE certified master tech in automotive and heavy trucks so I do actualy know a little about cars, no I'm not trying to brag I'm just trying to let you know that I'm not just some guy talking out of his pooper!
LMAO!! Seriously guys the main reason I come on these different chat roms is to help out those who ask for it, he asked so I tried to help. OK maybe he didn't ask right now but his engine is, and in a few months to a years time when his engine does die then he would be too, I'm just trying to head that off at the pass is all.

 

no You sound like a some guy who knows something about cars that is talking out of his pooper!!!! Really I am just kidding. Your help is appreciated by me. I have learned some things on this thread. I have raced motorcycles and have apprenticed as a mechanic plus my certificate in auto/diesel so when someone talks engines and transmissions I can learn easier than the next guy cause I have some education and experience on the subject at least. you can't know all the tricks of the trade. I am sure your still learning about mechanics. why else would we be involved. that makes it fun.

 

All right if I'm going to get my tuner back up here for this I am running 16-17 degrees of timing causing about 3-5 degrees of knock retard how much should I be running and what is a good a/f ratio? 11.5 or more towards 12?

 

Saddly for this you need someone whos tuned one of these guys to answer you. I may know some stuff but when I'm out of my league I'll admit it.

But if you need something to at least try then I'd bump up the fuel a tad and pull out a few degrees of timing and see what happens. I can't give you exact #'s man, sorry.

LMAO!!! Thanks! But no I never said I know everything about engines, I just know enough to keep me out of trouble and to try to help those who are getting into some.

 

Either way you just made my buddy list cause your a good ****! sounds like you maybe close to my age too! lol not that I am an old fart but I am not young,dumb,and full of cumm anymore. I am older, dumb, and sucked dry.....LOL

 

At what RPM during 3rd, 4th are you experiencing knock? is it during WOT? What kind of fuel do you have available in your area? 16-17 timing advance should not be creating knock, especially running 60lb injectors. Do you have a dyno sheet with an A/F read-out? Also what is your tuner using to tune your ride? HPT? If so, post the .bin file and I'll take a look at it. Also, do you know what your IAT's are at WOT?

 

i get a hair of knock in 4th at 5 grand then drops, but sill in the process of street tuning with mase,and making fine adjustments on the road, running 19 degrees timing if i remember correctly running 94 octane gas.

 

Follow TOFU, he'll know what to do.

Oh, should elevation be considered as well. I would think so.

 

Yes, good catch. Elevation is needed as well due to the adverse affects it has on air density.

 

which is why making adjustments on the street is key.