02's to high
- Thread starter donZ
- Start date
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don,
I have the same problem as you. My mods are in my signature. Basically I need to quit being lazy, and get an adjustable fuel-pressure regulator and a fuel pressure gauge. Do you have the stock (non-adjustable) regulator?? If so, I'd suggest replacing it (which I need to do). If you're running an aftermarket pump, but low boost levels (16psi or less) you're probably gonna be rich without an adj. FPR.
Or you could always just crank up the boost, and add air to the large amt. of fuel
Provided you can fend-off knock, which is always fun.
Good luck!
I have the same problem as you. My mods are in my signature. Basically I need to quit being lazy, and get an adjustable fuel-pressure regulator and a fuel pressure gauge. Do you have the stock (non-adjustable) regulator?? If so, I'd suggest replacing it (which I need to do). If you're running an aftermarket pump, but low boost levels (16psi or less) you're probably gonna be rich without an adj. FPR.
Or you could always just crank up the boost, and add air to the large amt. of fuel
Provided you can fend-off knock, which is always fun.Good luck!
charlloots
SMO-CUM
- Joined
- Aug 1, 2002
- Messages
- 712
Originally posted by donZ
how do i get my 02's down ?
they are running around 820 to 840 ?
bring your fuel presure down 2 psi at a time until your where you wanna be with your O2's 750 - 770@ wot . you will see knock with your O2's that low with street gas 820 aint that far off i think some guys run that rich on the street to be safe.find out about the chip .
I would leave it alone. Go ahead and try the 2 psi FP adjustment. If it knocks, put it back. your o2's are pretty close. I have been through this a few times and that is as low as I can get mine without knock. I also have read some threads on this that some guys don't take a lot of stock in o2's. I think it is marginally accurate for a tuning tool. Just my O2
I'm presuming pump gas. I'm also presuming you are not already detonating...
MI gets 93 octane, doesn't it? If the chip has "street" timing ~820+ is safe. If you aren't detonating at the top of third, try another 1# boost. If you lower the FP, I wouldn't take it below ~40.
:-Dean
MI gets 93 octane, doesn't it? If the chip has "street" timing ~820+ is safe. If you aren't detonating at the top of third, try another 1# boost. If you lower the FP, I wouldn't take it below ~40.
:-Dean
blackbuick87
Senior Member
- Joined
- Mar 11, 2002
- Messages
- 3,205
A stock O2 is not accurate enough to tune by the way you are interpreting it. As long as you are not getting knock or fouled plugs, slow spool, or a giant puff of black smoke out the back dont worry about it.
If it makes you feel better you cant probably drop the FP 1-2# as long as youre not getting any knock
If it makes you feel better you cant probably drop the FP 1-2# as long as youre not getting any knock
donZ - It depends on the fuel. Different fuels have different resistances to exploding, which is why higher octane gas is generally preferred. As you run leaner, you run hotter, and the heat will ignite the air/fuel mixture, so, the more resistant the fuel is to detonation, the leaner/hotter you can run.
No specific O2 value is "correct", particularly from car to car, but the O2 value can indicate trends and ranges. The NB O2 sensors we are strapped with may not be the most accurate way of tuning an engine, but since that is all we got (for most of us, for the most part), try these guidelines with a stock setup:
91 - 14psi, 18* WOT timing, ~.820-.840 O2s
93 (91/100 blend) - 17-18psi, 18-20* WOT timing, ~.800-.830 O2s
95 (91/100 blend) - 18-20psi, 18-20* WOT timing, .770-800 O2s
100 - 20psi, 22-24* WOT timing, .750-770 O2s
This is my experience and with unleaded fuel only. We have pretty crappy "premium"gas here in CA, oxygenated and rated at 91 octane. "Premium" gas in your area may be better. Also, every car is different so yours might be able to tolerate a little more boost or timing for a given fuel, netting different O2 readings. Throw in a FM, or a larger turbo, or P&P heads/intake, etc., and that all changes. Currently on my car (FM/PTE52) on 100 I run ~25psi, 22-24*, .730-740 02s, -1.0KR @ the top of third, locked.
If you have very little KR now, sounds like you are pretty much at the limit of the fuel. You could try GM Top Engine Clean to clean up the combustion chambers if there is significant carbon buildup (creating an incandescent ignitor). A cooler intake charge (relocate intake to a fresh air source) can sustain a leaner mixture as it will help keep the AF mixture from exploding.
Here's a decent writup on
Fuels, Detonation, and Preignition that explains quite a bit about fuel.
And here's one on tuning: Bruce Plecan's Tuning Tips
blackbuick87 - BINGO! Tune the car to the edge of detontion/preignition, and then back it off a tad to allow for operating environment changes. The O2 numbers will be what they will be!
:-Dean
No specific O2 value is "correct", particularly from car to car, but the O2 value can indicate trends and ranges. The NB O2 sensors we are strapped with may not be the most accurate way of tuning an engine, but since that is all we got (for most of us, for the most part), try these guidelines with a stock setup:
91 - 14psi, 18* WOT timing, ~.820-.840 O2s
93 (91/100 blend) - 17-18psi, 18-20* WOT timing, ~.800-.830 O2s
95 (91/100 blend) - 18-20psi, 18-20* WOT timing, .770-800 O2s
100 - 20psi, 22-24* WOT timing, .750-770 O2s
This is my experience and with unleaded fuel only. We have pretty crappy "premium"gas here in CA, oxygenated and rated at 91 octane. "Premium" gas in your area may be better. Also, every car is different so yours might be able to tolerate a little more boost or timing for a given fuel, netting different O2 readings. Throw in a FM, or a larger turbo, or P&P heads/intake, etc., and that all changes. Currently on my car (FM/PTE52) on 100 I run ~25psi, 22-24*, .730-740 02s, -1.0KR @ the top of third, locked.
If you have very little KR now, sounds like you are pretty much at the limit of the fuel. You could try GM Top Engine Clean to clean up the combustion chambers if there is significant carbon buildup (creating an incandescent ignitor). A cooler intake charge (relocate intake to a fresh air source) can sustain a leaner mixture as it will help keep the AF mixture from exploding.
Here's a decent writup on
Fuels, Detonation, and Preignition that explains quite a bit about fuel.
And here's one on tuning: Bruce Plecan's Tuning Tips
blackbuick87 - BINGO! Tune the car to the edge of detontion/preignition, and then back it off a tad to allow for operating environment changes. The O2 numbers will be what they will be!
:-Dean
