Convert 2000 F-Body OS to a Flex Fuel OS?

[98 tigershark]

I thought this is an RX7 LS1 Race Car, WOT no LTFTs! What you say is true eventualy and if the LTFTs arent disabled. This is with a WBO2 AFR gauge from the WBO2 directly, also!!

1.) But if you have a new tank of fuel (I would love to say gas but those days are gone) You will get an AFR reading on the WBO2 sensor that is approx +6% out on E10 if the AFR is set to 14.63 for gas for around 10 -20 minutes until the LTFTs adjust, That is right I think. But you can tell what is in your tank by the WBO2 AFR gauge for a short period it would seem and let you know also especially if the trims are way out. So with V2 you just carry a tune or two for the E%. It is not a flex fuel setup for sure but it is not to bad I think for a setup you already own so you dont have to buy a sensor for $400.00

2.) In the case of this thread and the RX7 LS1 race car it will be under WOT mostly, so no LTFTs. It is already E70-98 about 20-25% difference and the AFR gauge should show this w/out ltfts and . Then w/RR you change that (B3601) on the fly w/RR when you start the car up after it is warmed, right? How hard is that? I must be missing something here, I have not used RR but that is my understanding. No need to reflash and change on the fly and would be a great setup for this application as apposed to a flex fuel setup that is questionable?. Again not a flex fuel but this will work right w/RR. You have one and I dont so is that correct no need to reflash and change on the fly? The main idea here is the AFR gauge and what it says and then change b3601 on the fly. If what I have said is correct that is pretty close to a flex fuel setup as we can get I think?
Let me know,
98 tigershark

Without the sensor you won't know exactly what E% you have.
I don't see how AFR will tell you, if LTFTs are being used they will get you to
B3601 regardless of what is in the tank.

If WBO2 reads lean or rich the RR will multiply BEN to VE or MAF to get to commanded,
but with our OS commanded AFR won't change on it's own.
You can set up the RR many different ways this is just one example.

Obviously you won't use the RR with LTFTs but in OL with B3605 or B3616(filtered).
B3605 is in EQ only and will/would change if you had the sensor and FF OS.

[mr.prick]

1: OL is not dependable IAT&ECT ect. will have an impact on VE/MAF.
If you command xx.xAFR and you have the RR configured to adjust with BEN
then it (RR) will continuously adjust to get AFR to match commanded "on the fly" VE/MAF up, VE/MAF down.
AFR will be as closed to perfect all the time,
but if you change E% in the tank without the ability of the PCM to change EQ1 on it's own then you still need to change B3601 manually which in turn will change B3605 and B3616 ect.

2. I don't know if simply changing fuel in the tank will directly affect AFR
because I have no way of knowing what exactly is in the tank.
With VE/MAF being tuned before hand,
I imagine that AFR would be the same with gas as it would with E% thus the need to change B3601.
This may not be the case in OL but in CL LTFTs/STFTs will keep you @ EQ1
they won't change EQ1.

I could be wrong but I don't think you should use AFR difference to determine what's in the tank,
though I don't know from experience whether or not
simply changing/adding E will change AFR.

For OL the RR will keep AFR perfect, provided it is configure properly.
If you want to run straight off WBO2 for VE/MAF it is the only way to go.

In the case of the OP adding the sensor and FF OS is not a problem with a hybrid build, for you and I it's gas or E or find a way to integrate the sensor and OS.

[98 tigershark]

I am a thick headed Norwegian, but I think i finally got it. And yes,OL,WBO2 with RR with AFR VE and Maf is What I wiuld like to do this winter.
Thanks, its just frustrating w/E10 here, it could be anything.
Thanks
98 tigershark

[coctostan]

I've been away for a bit. I haven't made any progress on this as the car is still getting sorted. It was recently tuned on the 2002 F-Body OS. That is step one. The next step will be to transfer that tune to one of the flex-fuel OSs with the flex fuel sensor disabled. This way I will be able to see if it needs repinning (my research says it doesn't, but you know how that goes).

If I am able to get it running gasoline on a flex fuel OS without the sensor, I will buy a sensor, hook it up and start tuning for increasing amounts of ethanol.

To address the discussion from the past few days, I will say that I'm only interested in true mixture compensation. I don't want separate tunes for E98, E85/70 and 93 octane gas. I also want the tune tailored to the actual mixture, not a guess. The flex fuel OS can alter fuel/timing according to the mixture. Pretty slick.

I can get a sensor for about $350. If it works, that isn't all that bad.

The reason I want to run Ethanol in a N/A road race car is because it will run much cooler and potentially with more power. I have access to E98 and there is much E85 around here. Unfortunately, sometimes I will be in an area where there is no access to ethanol and I will end up with a mixture of gasoline and ethanol. It could be 50/50.

[mr.prick]

I am in full agreement with your reason for doing this now,
at first I said use one or the other but this "swap" is going to be awesome.
It would be nice to have a COS that would incorporate the FF tables to
an F/Ybody OS, I bet it would be easy for Ross to do.

From what I have read the old FF sensor is more accurate
than the newer "virtual" setup.

Good luck with your project.