BCNUL8R

iTrader: (2)

Car is a 2004 gto p59 ecu.

When I'm done tuning the VE table should I enable the stft under open loop?

Re-enable closed loop or stay in open loop?

What about dfco?

Im just going over the things I disabled for speed density tuning and want to know the advantages and disadvantages of staying in open loop vs re-enabling some of these things.

Jim Cuff

I am in the same boat. still full OLSD, except adaptive idle. I havent driven much just getting idle and part throttle going. I am surprised how well OL runs. My temps have changed a lot and the car seems to respond well. I am thinking DFCO,STFT and a pro tune and I will be good.

BCNUL8R

iTrader: (2)

brandon6.0

iTrader: (32)

I run the tbss in open loop. Been ran like tht for a yr. Throttle responce feels better to me. Only thing is the tune can change up some with weather changes and altitude.

If you feel the tune is done. Go back and enable dfco, short terms if u want closed loop. The stft open loop is a nice feature as well. Try tht if u like open loop.

BCNUL8R

iTrader: (2)

brandon6.0

iTrader: (32)

Yea if u like how it runs in open loop thin leave it. U can even set up a lean cruise as well.

G Atsma

Doesn't running in open-loop, speed density sorta defeat the purpose of having a computer-controlled engine? This way the computer has NO CLUE as to what the engine is taking in or putting out, exhaust-wise. Yeah, the response is pretty good MOST of the time, but efficiency has hit the bricks, except for some times... Might as well run a carb...

BCNUL8R

iTrader: (2)

It runs pretty darn good except the throttle tip in kr. I think I was on the wrong track trying to compensate for it on the VE table and need to look at transient fueling instead. Other than that and relocating the iat sensor it's doing well. I just want to know if there was a correct way or if it was a matter of preference on staying open loop or going to closed loop.

brandon6.0

iTrader: (32)

Well large cams, headers, etc mess with o2 readings. Most big time racers run full open loop. Like i said i run the tbss in open loop. Havnt seen any issues with it. Ive ran it in closed loop but fueling is always moving around.

With open loop i can set it up to idle leaner for a better lope at idle, lean cruise in the high 15s afr. Also can control my fueling to what i want without it changing.

brandon6.0

iTrader: (32)

To the OP try disabling burst knock completely! If that doesnt help try messing with PE enrichment rate. Try bringing pe in faster. If its a lean spike on tip in.

If this doesnt help play with transient. Ive never really had to mess with transient tho

BCNUL8R

iTrader: (2)

Ok, under burst knock I raised the enable delta cyl air to 6 at all rpm's. It was 2.

I already lowered the boost enrichment from 110 to 105 kpa and increased the ramp in so I no longer get a lean spike or any KR in that area.

The only KR I get now is from a lean cruise rolling into it, but not enough to get into PE. I have an auto and I was rolling into it, but trying not to give it enough to down shift. I went ahead and added a little to the VE table in those areas and pulled some timing as well. I'm usually cruising at around 15.2 AFR. Idle in park/neutral is 15.2 as well while Idle in gear stopped is 14.7. It seems to like that. Just rolling into it in certain circumstances I get some KR.

Now I just need some warmer weather and dry roads to see if what I did makes a difference.

brandon6.0

iTrader: (32)

I zero out the burst knock timing advance table. It is basicly a predicted knock table. Not needed! Another one of those stupid gm tables lol. Do away with it completely.

gametech

iTrader: (1)

I would disagree wholeheartedly with your sentiment. The computer only has to correct for imperfections in the tune. If properly tuned, EFI can run better without closed loop. The big question is whether you have tuned under ALL possible driving conditions, including eventually deteriorating components, both mechanical and electrical. This is rarely the case, hence closed loop corrections. In the case of enthusiasts who tune for themselves, the car is much more likely to be properly tuned for any condition that it will normally be driven in, and is more likely to have the tune regularly checked for any changes that may be caused by component wear. That being said, a properly tuned carb can run pretty damn good.

qweedqwag

I agree mine runs pretty damn good.

G Atsma

For only ONE set of circumstances. ANY other time, gotta retune....
But I DO agree with the rest of your post. As long as one stays on top of the tune, Open loop/speed density CAN do well.

brandon6.0

iTrader: (32)

narrow bands can make a bad tune seem decent!
OL can make a good tune look even better!

BCNUL8R

iTrader: (2)

Since this is my first time using SD and my tuning was done between 45 to 55 degrees how much of a change can I expect in 80 degree weather? Are we talking a minor VE table adjustment and maybe a base idle airflow adjustment?

On the subject of tip in knock out of curiosity I looked at stock tune files from both a 2002 Camaro and a 2004 zo6 to compare. The knock settings were setup way more sensitive on the gto then the Camaro and the zo6 was setup even less sensitive than the Camaro.

With street tuning I can't really get accurate plug readings for AFR, but the porcelain is perfectly white with no specs at all so I'm really doubting that there is any real knock.

I did go ahead and raise the VE numbers in a couple areas and take a little timing out of the area anyway. If I'm still seeing kr there I'll try getting some race gas, but unleaded race gas is no where to be found near me. Trying to avoid xylene as well, but I really want to be 100 percent sure it's not real knock before I change the sensitivity of the sensors.

brandon6.0

iTrader: (32)

The gto are way over sensitive from factory. Just double the decay rate from from 2-8krpm. If its really knocking u will still know. Gen4 have sensitive knock sensors. On side of block instead of under intake

gametech

iTrader: (1)

Typically, you can get most of your weather correction handled with the IAT vs ECT bias tables with SD. That is, however, assuming you have correct values for injector flow and your VE is fairly close. This brings up the one glaring deficiency with OLSD. There is always the possibility of heat soak while sitting in traffic screwing with your IAT readings. With any movement or just wind giving you some airflow around the vehicle this problem goes away.

G Atsma

This is what I was driving at in my post above. There are too many environmental variables to depend on an OLSD setup to run consistently. The engine is operating under the constraints of programming, instead of real-world conditions. MAF's and O2 sensors are very dependable, and for street use there is not much reason not to use them if you have them anyway.