The car gets super lean when I put VP racing fuel in... is it the O2 sensors that get contaminated with lead or is it that the density is difference and hence it gets leaner for it...

Why is it? and why does the car run so much better leaner with VP? It also lights up my Check engine light with DTC 64 which is right O2 lean.. on my pops Z06 I have seen the same thing...

Let me know your experiences.. Thanks

 

TTT

 

Nobody knows???

After using VP my car has been running LEAN all the time.. even after O2 installation.. could it be that there is still some more VP left on the tank?

LMK

THanks

 

I answered this on Advanced Tech. You mentioned using C-16. That fuel contains 6 grams/gallon of lead. You have probably destroyed the O2 sensors. C-16 is a high density leaded fuel for big turbo boost and big nitrous hits. Although it has a high density when compared to most other leaded racing fuels, it is probably less dense than the typical unleaded pump gas, or even 100 octane unleaded racing fuel. Since the injector delivers a fixed "volume" per given pulse width, using a fuel that is less dense means you get less # of fuel for each pulse width, and it will lean out, since A/F ratio is # of air/# of fuel. The O2 sensors would handle the correction pretty easilly, at least if they didn't have to contend with the lead contamination.

What are you running that you need 117 motor octane fuel, costing $7.50/gallon?????

 

Well... I made a mistake with the leaded and the O2 as i know the lead is very good for the valvetrain... anyways.. I replaced the O2 sensors and I tried to use up all the VP fuel before fillup..

I am not running heavy boost I was just trying to tune with better timing to get more power out of the setup...

Next time I will use very little of unleaded. As I see there is not that much advantage for now or for that type of fuel...

I hope that with the residues I haven't destroyed my new O2 sensors.. Anyways..

I changed the right one yesterday and today I changed the left one.. Now the numbers seem prettier... THey were where they should as before I poured 4 gallons of VP C16. But after a few sprints the Sensors are back again reading extreemely lean again


the car hessitates and it has trouble since there is too much fuel, specially at idle..

I wanted to run more timing safely on the track since I was going to use ice to help out even more since running less retard on the BTM netted 5mph increase...

The advance tech post was more of a question of the benefits and disadvantages and touches this problem.. but this one is directly to my problem...

Let me know what you think.. I hope I haven't destroyed this new set... They just "touched" this fuel... since I tried to use up all the racing fuel before filling it up again and changing the O2s

 

Running 4 gallons of leaded fuel shouldn't destroy the O2 sensors.... only extended use. I believe the stock sensors can handle 50 hours of leaded use. I run C-16 all the time at the track, and even though I no longer use the O2 sensors for feedback to the PCM, they are still hooked up, and I can read them with my ScanMaster. One of them seems to be fairly accurate, but the other one reads way leaner, even though a wide-band check showed both banks running the same.

I don't know the SG of the fuel you normally run and had the car tuned for, but if we assume you went from 0.78 SG pump gas to the 0.73 SG C-16, the fuel system was delivering 6.5% less mass of fuel, and that would be equivalent to leaning the A/F ratio out from 12.0:1 to 12.8:1. But that isn't enough to throw things so far out that it couldn't be easilly accomodated by the long term fuel corrections. It shouldn't show up as a "lean" in closed loop, which is where the code is set. But it could lean things out in power enrichment mode, where the O2 feedback is ignored.

 

I dont know.. but the BLMs where in the 160 and Ints where in the 190 range...

I dont understand why...

Anyways....

What would be your recommendation for track use??? I am in the vecinity of 600rwhp...