COS5 question for ROSS

[kbracing96]

I wanting to set my truck up to be able to run on gas or E85. I'm pretty sure I can swap it over from the CO3 I'm running now to the f-body COS5 with the switchable fuel adders and timing modifier. My question is this. The timing modifier will only pull timing and i want to add it. Can the the limit for it be changed to allow negative numbers in it, so I will actually add timing? Right now it low limits at 0.

Since I'm going to be running gas most of the time since E85 is not readily available to me, I would like to keep my normal tune for gas and just flip the switch for the E85 tune.

Can you do this Ross?

[vatman02]

I was wondering the same thing. That way if I go on a road trip I wont have keep changeing the tune when I can't find E-85.

[GMPX]

It's not so much a limit, it's the way the PCM handles that part of the calculations, it subtracts only. I would need to change it to a signed value then add it instead. Best I can do is say that when I redo the GenIII custom OS's (whenever that might be) I'll correct it to work that way.

Something else, there was one operating system in 2002 using the 512K PCM that worked with E85 fuel, but you need the special sensor in the tank.

Cheers,
Ross

[vatman02]

It's not so much a limit, it's the way the PCM handles that part of the calculations, it subtracts only. I would need to change it to a signed value then add it instead. Best I can do is say that when I redo the GenIII custom OS's (whenever that might be) I'll correct it to work that way.

Something else, there was one operating system in 2002 using the 512K PCM that worked with E85 fuel, but you need the special sensor in the tank.

Cheers,
Ross

Thanx for the info Ross. Do you think this os will work properly in a different vehicle, and be compatable with cos 5? I found the sensor for about $300, but it would have to wired to the pcm to function correctly.

[TAQuickness]

KB - could you set your base tune to support E85 then allow the COS to pull the timing for Gas?

[GMPX]

Well, the OS would work but the issue (for an F-body) would be that the calibrations were only ever set up for the trucks. If I actually had some spare time it would be a neat thing to get going for you, but I don't. I'll have a quick look next week to see what would be involved. Oh, the E85 OS is - 12216125, if you could run the F-body OS 12212156 as the base then it would make life much easier, for the trucks they should be able to run 12216125 as is. kbracing96, what OS are you running now?
Maybe TAQuickness suggestion would work well though?

Cheers,
Ross

BTW - $300 for the sensor!! ouch

[vatman02]

Thank you for the help Ross. TAQuickness has the same idea I did, but we would need to decrease fuel as well.

[kbracing96]

Well, the OS would work but the issue (for an F-body) would be that the calibrations were only ever set up for the trucks. If I actually had some spare time it would be a neat thing to get going for you, but I don't. I'll have a quick look next week to see what would be involved. Oh, the E85 OS is - 12216125, if you could run the F-body OS 12212156 as the base then it would make life much easier, for the trucks they should be able to run 12216125 as is. kbracing96, what OS are you running now?
Maybe TAQuickness suggestion would work well though?

Cheers,
Ross

BTW - $300 for the sensor!! ouch

Ross, I'm running 01270003. I just happen to have a flex fuel composition sensor laying around too.

My reason for wanting to keep the COS as my gas tune, is that for the most part E85 is not readily available to me. I have to drive about 20 miles to get to a pump as it is now, but would be worth it with the turbo, to have the better gas for boost This summer, I my be heading up to Colorado and it's all over up there.

[Slowrc]

Has anyone done this. I only have one local station with e85 so I'd like to have a switch to go back to a gas tune if need be. Anyone???

[JezzaB]

Why cant you just tune for the E85 with COS5 and make sure the N2O switch is active and it will add the extra timing {A0016} for the E85 with the custom table and set the N2O VE Multiplier {A0015} to 1.30 (for example) for 30% more fuel for the E85.