Cobb AccessPORT Discussion
#1726
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Jeff will most likely email you FI maps based on your turbo. I don't know for sure though, I think I heard him mention some kind of subscription service at one point.
Either way; you'll be taken care of by Jeff and it'll be worth every penny.
Either way; you'll be taken care of by Jeff and it'll be worth every penny.
#1727
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I'm starting a test on stage 1 with 89 octane gas. This tank is a 93/89 octane mix. I doubt I'll have a problem seeing:
a) I hit mid 15's at WOT without pinging on 93 octane
b) use to run my CZ tuned to a bit over 13.0 afr with a bit of ignition advance on 89 octane
But you never know what will happen... i'll keep my ears open and AP watching the knock retard. My car always gets much better fuel mileage on 89 octane for whatever reason so thats why i'm giving it a shot. Perhaps it is the weak ignition system or i'm low on compression which leads the car liking a more easily igniteable fuel... no idea
a) I hit mid 15's at WOT without pinging on 93 octane
b) use to run my CZ tuned to a bit over 13.0 afr with a bit of ignition advance on 89 octane
But you never know what will happen... i'll keep my ears open and AP watching the knock retard. My car always gets much better fuel mileage on 89 octane for whatever reason so thats why i'm giving it a shot. Perhaps it is the weak ignition system or i'm low on compression which leads the car liking a more easily igniteable fuel... no idea
#1729
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yes, that would be why some high performance engines ping with lower octanes. Ping is detonation which means the fuel combusted before it was suppose to because of the temperature in the cylinder. So essentially, the higher the octane the more work the ignition system has to do in some respects.
#1730
Power!!
The basic premise of octane.
The higher the octane the more adverse to autoignition and the slower it burns. So you can compress higher octane gas more with less chance of autoignition and it burns slower so you can run more ignition advance.
The higher the octane the more adverse to autoignition and the slower it burns. So you can compress higher octane gas more with less chance of autoignition and it burns slower so you can run more ignition advance.
#1734
Illudium Q-36 Space Moderator
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Off topic - but hey.
Flame Speed of Gasoline depends on the chemical makeup of the gasoline itself - and has nothing to do with Octane. Think big nasty chemical equation breaking gasoline compounds and oxygen to form new compounds.
Octane refers to what we call sensitivity in the explosives world; which is the initiation of the chemical reaction all by itself (auto-ignition). Once you have a sensitivity rating / octane - does not refer to the power of the reaction - only the amount of initial energy required to initiate it. So a higher sensitivity/octane means it takes XYZ more energy to start the breakdown. That is why you can advance ignition et al - because the heat from the compression of the mixture is less likely to be high enough to initiate the explosion.
That is why we can run around with military dynamite in a backpack; but you can't do that with civilian dynamite - but they are both the same explosive force.
Flame Speed of Gasoline depends on the chemical makeup of the gasoline itself - and has nothing to do with Octane. Think big nasty chemical equation breaking gasoline compounds and oxygen to form new compounds.
Octane refers to what we call sensitivity in the explosives world; which is the initiation of the chemical reaction all by itself (auto-ignition). Once you have a sensitivity rating / octane - does not refer to the power of the reaction - only the amount of initial energy required to initiate it. So a higher sensitivity/octane means it takes XYZ more energy to start the breakdown. That is why you can advance ignition et al - because the heat from the compression of the mixture is less likely to be high enough to initiate the explosion.
That is why we can run around with military dynamite in a backpack; but you can't do that with civilian dynamite - but they are both the same explosive force.
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#1738
Illudium Q-36 Space Moderator
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Really lean and really retarded would be the hottest combo for the cat (I think). Short story long; the cat is supposed to be good up to 1600 degrees or more (per Jeff); and boosted I have only seen 1500 (wot; high boost 10 second run uphill).
#1739
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but when you are boosted, some of that heat is lost in spooling the turbo, so it may be hotter for N/A
i know too much advance would be stupid and could be really detremental.
i know too much advance would be stupid and could be really detremental.
#1740
Illudium Q-36 Space Moderator
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If you wanted to be that ragged edge; at this point I would go:
1 - Get spark plugs with pressure sensors built in; log for max pressure as close to 12-15 ATDC.
2 - Get a pyrometer wired - or use the built in cat temp sensor.
3 - Strap it to a dyno and advance ignition as far as you can; then start leaning out the mixture until a) you ping or b) the cat temp exceeds the specs from Mazda.
THAT would be a ragged edge tune.
1 - Get spark plugs with pressure sensors built in; log for max pressure as close to 12-15 ATDC.
2 - Get a pyrometer wired - or use the built in cat temp sensor.
3 - Strap it to a dyno and advance ignition as far as you can; then start leaning out the mixture until a) you ping or b) the cat temp exceeds the specs from Mazda.
THAT would be a ragged edge tune.
#1744
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I'm starting a test on stage 1 with 89 octane gas. This tank is a 93/89 octane mix. I doubt I'll have a problem seeing:
a) I hit mid 15's at WOT without pinging on 93 octane
b) use to run my CZ tuned to a bit over 13.0 afr with a bit of ignition advance on 89 octane
But you never know what will happen... i'll keep my ears open and AP watching the knock retard. My car always gets much better fuel mileage on 89 octane for whatever reason so thats why i'm giving it a shot. Perhaps it is the weak ignition system or i'm low on compression which leads the car liking a more easily igniteable fuel... no idea
a) I hit mid 15's at WOT without pinging on 93 octane
b) use to run my CZ tuned to a bit over 13.0 afr with a bit of ignition advance on 89 octane
But you never know what will happen... i'll keep my ears open and AP watching the knock retard. My car always gets much better fuel mileage on 89 octane for whatever reason so thats why i'm giving it a shot. Perhaps it is the weak ignition system or i'm low on compression which leads the car liking a more easily igniteable fuel... no idea
If you hit mid 15's at WOT on 93, isn't it dangerous to run that same map on 89? What Fuel Trim do you get at WOT on 93? If the trim is already adding more fuel, it could mean trouble.
I wonder if Cobb's economy mode will safely run 89 octane during summer time.
#1745
For those of you with NA 8s and an AP. What is your intake air temp? Also at what temprature was it when you took your reading?
I have been seeing between 110 and 120 in 50 degree weather. Not sure if this is good or bad?
I have been seeing between 110 and 120 in 50 degree weather. Not sure if this is good or bad?
#1747
Bigus Rotus
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From around 50 degree F outside, can't really remember
Last edited by Nemesis8; 04-17-2008 at 12:11 PM.
#1748
the AIT depends on ambient, but also your traffic conditions (how fast you are traveling). Pulling up to a traffic light can make the temps go up to insane numbers.