Speed Density & Open Loop

If you're modifying or tuning General Motors vehicles then you have heard the terms speed density, open-loop tuning, and standalone harness. In this #TechTuesday, our GM Instructor Steve Morgan​ joins Brett McClelland to give you the 101 of what speed density & open-loop tuning are and which method you should be using.
How to Properly Understand Your O2 Sensors: Vehicle Oxygen Sensors & Their Role with Fuel Trims:
• How to Properly Unders...
Fuel Trims & The Tuning Process:
• Fuel Trims & The Tunin...
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[@Christdeliverme]

I hear a new Ferris movie is underway and you're apparently playing lead role! Congratulations! :D

[@TheTuningSchool]

Lol. Nah, tuning is our thing. And we have a pretty high buyout price.

[@notsure7874]

When you mentioned people deleting 02 sensors, my first thought was "at that point, just get a carb intake and a spark box" and then you said it :D :D I personally have deleted MAF and the after cat O2's on my swap - but that's not because it's a swap, or because it's a standalone harness at all. It's because it's just beyond the capability of a MAF, and it's a track only car. So I'm not worried about drivability. I'm worried more or less about WOT only. Speed density is "the way" ... for ME. To be a "standalone" you don't have to delete ANY sensors. Matter of fact, the easiest way to swap is to NOT delete any sensors. All you really have to do is remove vehicle wiring from the harness, and do a 3 wire hookup. With all the sensors it had to begin with. Oh, and turn off VATS and maybe some DTC's for after cat O2's. But you don't have to delete those either! Exactly 0 other tuning required.

[@lsxtuner6126]

I tune my own car in open loop, but I will not tune someone else's car and leave it in open loop. The iat and ect still effect fueling so you can use the bias to help keep low speed fueling more consistent. I like to setup a leaner than stoich idle as well as a leaner cruise for highway speeds so open loop works well for me on an aggressive cammed/boosted motor. With an accurate iat and tuned iat/ect bias you can keep low speed fueling changes due to weather to a minimum non consequential difference. Excellent explanation and I agree open loop wouldn't be recommended in the vast majority of cases, but for the person with an aggressive setup and the ability to tune themselves then it can be desire able for some setups.

[@TheTuningSchool]

Hey, thanks for your feedback and input! We appreciate you watching and commenting on this video.

[@Calvotuned]

This guy knows what he’s talking about. 110% agree!!!

[@notsure7874]

I can see how that'd work really well - never thought of it like that ... I take back my "might as well run a carb at that point" comment! :D So I'm curious though - what benefit do you gain by removing the upstream O2's?

[@fasnuf]

Spot on explanation!

[@TheTuningSchool]

Hey, thanks for watching!

[@PS-pd1uf]

who sees ferris bueller?

[@TheTuningSchool]

No relation, lol.

[@CompoundKodiak4x4]

Have you guys done a video about narrow band O2 placement with modified exhaust or say a truck single turbo setup? Where is the best O2 placement for them when drivers side bank feeds passenger bank and passenger bank O2 see's both banks. Best tuning strategy?

[@OhMar1210]

Thank you 😀

[@TheTuningSchool]

No problem!

[@miguelvillarreal5188]

what’s is the best tune option for bracket racing i need to be consistent?

[@jeyanthitherce7274]

Thanks sir turning tablet calendar so much

[@frsguy5347]

Not all factory systems need to be deleted, just tuned for your driving style, good vid....

[@TheTuningSchool]

We appreciate you watching. Thanks!

[@exhaustsauce]

Brett for President! 2020

[@TheTuningSchool]

Yay! Our vote will be pending up until he reaches the age requirement.

[@exhaustsauce]

@@TheTuningSchool and height requirement.

[@edmundu]

How about a car that has factory wide band o2 sensors like coyote platform? Don't they have closed loop fueling adjustments because of widebands?

[@vonvoyage14]

Great explanation! I just have a question if I want to delete my o2 sensors, does the o2 functions on WOT? I have them disconnected and seems have idle issues only

[@garlandjones7709]

The computer doesnt use them for WOT. The still send readings, but the pcm will not make adjustments based off of those readings when under WOT

[@diduck6878]

Front 2 are for air/fuel mixture

[@jamest.5001]

I don't understand why disable O2 sensors? For anything Street, I'm planning a swap of a 4.8/5.3 in a 96 S-truck, I was thinking 3rd gen, but considering gen4, id like to get a 6L80, I'm looking for about 600hp Street turboed, swap nearly the whole harness, and piggyback what's needed for factors gauges in the truck ,allow the LS/vortex ecm control only the engine and trans, I may end up with a 4L60, if so I guess I'll eventually get a 4L80, but a 6L80 or 8L90 would be nice! Don't know if it's in the budget!

[@TheTuningSchool]

We don’t understand why anyone would disable the O2’s either. The build sounds like fun! Good luck!

[@snivesz32]

Do you tune VE in open loop or closed loop then?

[@SpeedDemonCBR]

I feel called out on the tuning on the way to work comment lol

[@TheMoody876]

My e38 when in open loop the commanded eq ratio slowly rises can not figure out why. Starts at 1.000 after 10 minutes of driving it gets upto 1.07

[@hassanabas1549]

Some one answer me if I want to tune my chevy caprice v8 that only have bolt ons on hp tuners I will only go to engine speed density and tune the ve map(maniflod air pressure) tables after loging it and I should be fine right someone answer me please

[@kurtperdew5601]

Do O2s influence VE tables then? If your running speed density with no MAF sensor then why would you even have an O2(assuming they don't correct VE table...)

[@TheTuningSchool]

The O2 will correct the fueling regardless of what airflow model the ECU is using to calculate the initial fuel input. “Speed Density” (VE only with no MAF sensor) is not the same thing as “Open Loop” (having no O2 sensors). This is a misconception. Thanks for your question! It's the reason we made this video.

[@kurtperdew5601]

@@TheTuningSchool Thanks for the reply. That makes perfect sense now.

[@TheTuningSchool]

@@kurtperdew5601 Not a problem. We try to keep up with the comments as much as possible, thanks for noticing!

[@byronboost]

bi heee cool

[@TheTuningSchool]

Fir shure!

[@MRHIM-cc7uh]

Do you guy have a contact information????

[@davidcunningham00]

so I need to upgrade to a ls7 maf

[@TheTuningSchool]

It's up to you! "Need" sounds so obligatory, lol

[@davidcunningham00]

@@TheTuningSchool well iam thinking about doing alittle something something to my Lq4 in my Chevy 2500 4x4 pickup with 33 mud tires

[@brookematthews616]

Anything on the gen 2 coyote it’s not the same

[@juanmangerita]

This is only for GM ? Change the title

[@TheTuningSchool]

Steve is our GM Instructor. However, that doesn't mean it only applies to GM vehicles. Thanks for noticing!