Custom OS/AutoTune Question

[VortechC5]

I will (finally) be starting to use AutoTune this week. I had been planning on doing AutoTune using my stock OS and then converting to a custom OS using the .tun file that I created using AutoTune.

I have a pretty good tune right now. It there any reason not to just convert to the custom OS now and run AutoTune on that?

Can I convert back to the stock OS if for some reason the custom OS won't work for me? I am currently still using my MAF and the custom OS will of course require me to go MAFless. My only concern is going MAFless at my high altitude of 7000+ feet.

[dfe1]

Switching to a custom OS does NOT require you to run MAFless. MAFless operation is an option, not a requirement. I've been experimenting with both a MAF and a MAFless calibration on my 01 C5, both using a custom OS. Once you have converted to a custom OS and added a calibration file, you can switch calibration files back and forth between MAF and MAFless with no problems. If you want to revert to a stock OS, you'll obviously have to do a complete reflash. Also note that if you convert to MAFless, you'll have to do some considerable rework to the predicted airflow table. If you don't and actual air flow exceeds predicted, the system will go into reduced power mode. No big deal, and easy to clear, but the throttle will have no effect until you clear the codes. My suggestion is to convert to the custom OS and retain the MAF. Do whatever tuning is required to get the car running the way you want. Then try building a MAFless tune. If it doesn't work out, you can always revert to the MAF cal.

[GMPX]

One of the main reasons for getting rid of the MAF is for boosted applications, well, you have to really if you want to run any sort of decent boost.

Cheers,
Ross

[VortechC5]

I think that I will try your suggestion to do a tune with the MAF and then progress to one without the MAF. Is predicted airflow the p1514 related table? I had to tweak that one when I put the Vortech on to keep it out of Reduced Power mode.


Switching to a custom OS does NOT require you to run MAFless. MAFless operation is an option, not a requirement. I've been experimenting with both a MAF and a MAFless calibration on my 01 C5, both using a custom OS. Once you have converted to a custom OS and added a calibration file, you can switch calibration files back and forth between MAF and MAFless with no problems. If you want to revert to a stock OS, you'll obviously have to do a complete reflash. Also note that if you convert to MAFless, you'll have to do some considerable rework to the predicted airflow table. If you don't and actual air flow exceeds predicted, the system will go into reduced power mode. No big deal, and easy to clear, but the throttle will have no effect until you clear the codes. My suggestion is to convert to the custom OS and retain the MAF. Do whatever tuning is required to get the car running the way you want. Then try building a MAFless tune. If it doesn't work out, you can always revert to the MAF cal.

[VortechC5]

That is one of the reasons that I want to go MAFless. I logged data on Saturday and my MAF frequency hit 11855 hz which is getting close to the max out value. Given a nice cool day with dense air and it may well max out. The only thing that keeps it from maxing out now is the lack of air density here.

Mark


One of the main reasons for getting rid of the MAF is for boosted applications, well, you have to really if you want to run any sort of decent boost.

Cheers,
Ross

[lplott]

Mark,

Are you going to complete a tune with the MAF, then tune with the MAF turned off or removed?

In-laws hit town today, will be lucky if I get to put the first coat of Zanio on the new paint this weekend.. :lol:

Lonnie

[VortechC5]

Lonnie,

I think that I will be sticking to my original 3-step plan. That is to finish developing a tune for the stock OS with MAF, then convert to the custom OS 01 version and go MAFless, and finally convert to the custom OS 03 version with 2 bar.

I am trying to find time to AutoTune but the new house thing is consuming much of my free time right now...

Mark

[dfe1]

I think that I will try your suggestion to do a tune with the MAF and then progress to one without the MAF. Is predicted airflow the p1514 related table? I had to tweak that one when I put the Vortech on to keep it out of Reduced Power mode.



The table is C6101. For your C5, I'd experiment a bit, rather than changing all the cells to max value. This will give you some protection in the event of an actual ETC failure. The C6101 table goes to 8000 rpm, so at the very least, leave the entries as they are, at any rpm higher than you plan to run the engine. I'd also stay on the conservative side at and just above idle for the same reason. With a blower, you're probably going to see actual air flows that are higher than the MAF can register, (even at 7,000 feet) which is one of the reasons for eliminating it. Once you adjust the C6101 table appropriately, you shouldn't have to worry about a 1514 code being set.

[lplott]

Mark,

What are you going to replace the MAF, a silicone coupler?

Lonnie

[VortechC5]

I'll probably just remove the MAF and hook my air filter directly to my intake tube. My setup uses a cone type K&N filter that is mounted in the driver's side of the nose of the car, under the headlight.

If you remove your MAF don't forget that you will need to install a separate IAT sensor. Our cars have the IAT built into the MAF. I have already done this. I got an IAT sensor and gromet for a 2000 Vette and installed it in the output side of my aftercooler. Then it is just a matter of rerouting the 2 wires for the MAF IAT from the MAF to the new sensor.



Mark,

What are you going to replace the MAF, a silicone coupler?

Lonnie

[lplott]

Yea, I think that actually removing the MAF will be last on my list of AutoTune mods. Think I will start with the MAF disabled using the IAT in the MAF.

After this is all done, think I will take it down and see if it will pass SMOG :?:

Lonnie

[VortechC5]

Didn't you remove your cats? If so your car will fail the visual inspection...



Yea, I think that actually removing the MAF will be last on my list of AutoTune mods. Think I will start with the MAF disabled using the IAT in the MAF.

After this is all done, think I will take it down and see if it will pass SMOG :?:

Lonnie

[lplott]

Yes, I had them removed. But Wanda got tired of the smell and I got tired of the complaining so I re-installed them.

Small price to pay considering all she has let me do to the Vette... :P

Lonnie

[caver]

Normally after the cat removal I install some dogs that normally takes care of any problems :lol:

[dfe1]

I hear that's all the rage in south Africa-- dogalytic converters. I've been wondering about importing them. do you have any sources?

[VortechC5]

I want to make sure that I understand what the various versions of the custom operating systems do?

01 version allows for running MAFless with dual spark maps. This makes me believe that the stock OS when run MAFless looses one of the spark maps. True? Does the 01 version have any other features.

02 version is the same as the 01 version but adds valet mode.

03 version allows for dual spark maps,also, allows for (requires?) 2/3 bar MAP sensors, and allows for semi-open loop tuning. Can someone please explain the theory of operation for boost enrichment when running this OS? Is it still PE or is it tied into the boost VE table? Any other features available? Can I upgrade to this OS now using my stock MAP sensor, reatain my current PE based boost enrichment, and then add the 2 bar later?

Mark

[mistermike]

03 Version doesn't mandate 2-3 bar sensors, but that's the one to use if you're going 2 bar. If you don't scale the MAP, it works like normal. The nice feature you pick up is the MAP/RPM/AFR table. This can be viewed as a PE replacement with much more flexibility, even in a N/A application. The technique of applying PE only at higher boost levels seems to be the way to go. Some folks prefer to do it with VE exclusively and leave PE alone altogether.

[VortechC5]

I just logged my first AutoVE session. It worked like a charm the first time that I tried it. :D

It is really hard not to get into boost while doing this especially at the higher rpms and higher manifold pressures.

I drove for almost an hour logging data and still did not hit all of the cells. It is really hard for me hit all of the cells because of the lack of air density here. For instance my MAP reads a little bit over 23 in/hg with the car off. At sea level that would be closer to 29 in/hg (I really need to train myself to think in kPa...)

FYI, the +15% that the tutorial has you add to the VE table made my car way rich.

[caver]

I drove for almost an hour logging data and still did not hit all of the cells

Its almost impossible to get a decent cell count at the high rpm light throttle cells.

I do below 4k and full throttle on the road and the rest on the dyno.

I dont like doing all of them on the dyno as the cars build up heat quickly at the higher rpms.

Normally do 2 KPa ranges at a time up to about 70 kpa and from there I blend it into 85kpa.

Thats atmospheric where I am.

[VortechC5]

caver,

I was curious what atmospheric here is after reading that yours is 85kpa. I checked mine a little while ago and it is 79kpa here.

Mark

[BowlingSS]

caver,

I was curious what atmospheric here is after reading that yours is 85kpa. I checked mine a little while ago and it is 79kpa here.

Mark

Here in GA I am around 98kpa.

Bill