Speed density tuning questions
Thread Starter
Joined: Jun 2005
Posts: 2,265
Likes: 671
From: Oskaloosa, Iowa
Speed density tuning questions 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.
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.
On The Tree
Joined: Nov 2016
Posts: 129
Likes: 2
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.
Thread Starter
Joined: Jun 2005
Posts: 2,265
Likes: 671
From: Oskaloosa, Iowa
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.
I've got a little bit of work to do, but getting close. Snow put a delay to my tuning. I need to relocate my iat because during long idle periods in cold weather it will get heat soaked causing me to go lean at idle/slow cruise. Currently it's in the intake filter per procharger instructions, but I'm moving it to right in front of the throttle body. I also get some knock retard when rolling into the throttle from slow cruising speeds. If I get on it hard it doesn't do it. Also if I roll into it and get kr a little more throttle makes it come out of it. I pulled timing in those areas, but I think it actually needs a little more fuel in those areas. Other than that I'm close.
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.
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.
Thread Starter
Joined: Jun 2005
Posts: 2,265
Likes: 671
From: Oskaloosa, Iowa
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.
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.
So basically it's just personal taste as far as what you prefer? I need to work on the little kr I get on throttle tip in and double check everything when warmer weather gets here then I should be good to go. I may try just staying in open loop with stft enabled and stick with that.
TECH Senior Member
Joined: Jun 2016
Posts: 22,291
Likes: 3,616
From: Central Cal.
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...
Trending Topics
Thread Starter
Joined: Jun 2005
Posts: 2,265
Likes: 671
From: Oskaloosa, Iowa
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.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo 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.
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.
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
If this doesnt help play with transient. Ive never really had to mess with transient tho
Thread Starter
Joined: Jun 2005
Posts: 2,265
Likes: 671
From: Oskaloosa, Iowa
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.
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...
11 Second Club
Joined: Dec 2016
Posts: 665
Likes: 5
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.
TECH Senior Member
Joined: Jun 2016
Posts: 22,291
Likes: 3,616
From: Central Cal.
Thread Starter
Joined: Jun 2005
Posts: 2,265
Likes: 671
From: Oskaloosa, Iowa
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.
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.
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
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.
TECH Senior Member
Joined: Jun 2016
Posts: 22,291
Likes: 3,616
From: Central Cal.
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.