Whos running open loop all the time?

[thebrickbandit]

anyone running open loop 100% of the time? i like the idea of me telling the car the AFR i want all the time vs relying on the o2 sensors... its kind of old school thinking i know.... anyone here running open loop all the time? driving on the street and at the strip?

[N2speed]

If you think you can do better then a computer go for it. let us know the long term results in all weather conditions and various loads.

[LilSick]

lol

we never had all this fancy stuff in the 70's

or the 80's

for that matter, even well into the 1990's, we were building not just race cars, but daily driver pick up trucks, using mechanical fuel injection

i bought a brand new dodge in 1998 that had mechanical injection from the factory

is mechanical as efficient??

nope

is it as good with emissions?

nope

if you can tune, mechanical injection works great for racing tho : )

[DodgeBoy_8HP]

I guess it would be not a good idea long term… I agree with N2speed

[LilSick]

tuners do it all the time with other platforms

with my ducati 1199R (street bike) my moto gp buddy had hooked me up with his old ti system for next to nothing

i removed the narrowband sensors, turned off closed loop, tuned it, and rode that thing all over so cal

til some lady going south turned in front of me when i was heading north

3 months in the hospital - 3 months in a recliner - still have a surgery or two to go

twice they told me they were gonna cut my leg off

said not with my consent yer not...

you can stay in open loop if you want to - will make zero difference at the track.

[dodgeboy]

Why not put a carb. and distributor on it then?

[PurpleRam]

Depending on local legality.... and how militant the local emissions are , you could if you wanted to, cold weather starting is a P.I.A. , Two of my 70s Dodge?s are G3 Hemi Swapped , 1st is 75 Ramchager 4x2 with mostly stock 06 5.7 & TKO600 , cam however is a custom copy of the old 108 LSA version of the ?509 purple shaft? sometimes I run an 05NGC PCM with the Holley single plane and a 85MM TB sometimes it?s the MSD Hemi-6 box and a Holley 650 vac, mileage is better with the NGC, but with the carb/MSD setup, Idle is WAYYYYYYYYYYYY more Chop-Chop traditional ?509? sound , and it?s a crisper ride not sure how else to describe it, , I don?t drive it as much as I would like to, When I?m in the US , I do like to take it to local cruise nights, it starts easier with the NGC set up but the carb/MSD responds better to down shift and full Throttle type driving. The 2nd is a 78 D150 4x2 with a BGE 392 with a T56 in it that runs on a GPEC2 PCM , don?t care what the temp outside is, I hit the key it starts , None of that , 5-10 sec engine spinning over till it starts up.
I tune an 06SRT Magnum for a friend who lives in Munich Germany , that 449ci 6.1 (darton sleeve 4.165X 4.125 winberg crank) has been running a Drag pack intake and Holley 950 since the DP intake was released ,at 1st we used Diablo for timing , he/we did have a distributor set up on it for a while(PreFix racing) because the auto club he joined had mandated it for the ?track days?, they have since changed that ?rule? , Now we use a MSD hemi-6 box for timing ,used HP tuners for the NAG1 but Now it?s has a Tremec TR-6070 7 speed in it?.Soooo it?s just a Hemi-6 box now.
Some of the Dirt track and Truck pull guys I build for need to use a carb & distributor set up do to rules.
The 09 Challenger I do work for, (only engine and trans work, I?ve never had a chance to tune it) , he runs PA hill climb races(street not dirt) over the years he?s had many a ?pro internet tuners? FRP, Hemi Fever, Rick Trapp, OST , and a few more lesser guys do ?race tunes? for him, but in the end all of his best runs have been with a Prefix single plane/Holley 850/MSD box set up, same for when he does Drift competitions .
You will make more Peak HP with a Carb, but Tq average/HP average will always be better with computer set up, cold weather driving , extreme heat driving and towing , the Modern PCM set is just soooooo much better.


Meant to quote Dodgeboy's Carb comment post

[PurpleRam]

anyone running open loop 100% of the time? i like the idea of me telling the car the AFR i want all the time vs relying on the o2 sensors... its kind of old school thinking i know.... anyone here running open loop all the time? driving on the street and at the strip?

My 05 High mileage Yellow Bee(5.7l) Engine is 99% stock, only a 180 t-stat stock cast iron exhaust manifolds , stock Y-pipe and cats, 3.5in from the Y-pipe out to the side , has been running open loop since an hour after I rolled it off the trailer in 2020. It doesn?t start up as quickly as closed loop, but then again, all of the VE modifiers are either 0 or 1 , gets 16MPG around town and 20mpg on those few high way trips( with the 5.13s rear gear). Bought the truck with 288k on it , low 303k on it now.
My Black 05 bee with the 426 & TF727(or RH36 for you born after 1999)in it , is open loop, it?s never seen a Cl tune since I bought it as driveline less basket case.
My Yellow 05 bee with the 448&T56 is open loop. , the 448 has never seen a CL tune, when it still had the 398CI 5.7/Burnt up 545 combo that was in it when I bought the truck, the tune was your typical FRP ?hot street? type tune with some SCT trans tuning.
The 2019 1320 challenger I had, I ran it both open and closed loop, did CL only in the winter , drove that car for about 3 years I think I put 18k on it in that time frame , , Fuel Mileage was better in CL, the guy who owns it now (sold it in Oct 2022) has been driving it open loop since he bought it, he?s put almost 30k miles on it, he?s one of those every red light is a race type guys fuel millage is not even close to being on his mind.
if the end used is a 90/10 track type OL is the way to go , , if they are a 90/10 street type , go CL , Closed is better for the daily crowd ,if it?s a dedicated racer go open, don?t waste your time trying to get it to run in Closed loop , Cl = losing power.
let?s face it, if someone hits the track & races more than 6-10 times a month & drives the car/truck less than 3 times a week , they?re not interested in Fuel milage, , it?s easier to tune larger cams in OL.
I do a lot of Open loop tunes, and I?d say about 70% of them are daily drivers.
With Gpec and NGC4 Fuel milage is always better in Closed loop ?Period?.. no denying it, and when you can get a good tune for NN in the GPEC PCM?s, it?s night and day difference.
NGC3 from my experience Fuel milage can be better in Open loop, with the right tune, but ?.I?ve seen some OL tunes that have burnt up some expensive stuff.

[PurpleRam]

One thing that I?ve experienced in Closed loop that I?ve never had happen in Open loop,

When ECT is below 140 and Ambient air temp is 70F to about 75F when stopping abruptly, RPMs dip below 500 and snap back to say 700-800 idle range, I?ve had a few of these? jump ? like you just released a trans brake? I have a 02 ram here that I bought back in Dec 2024, it has a BGE 392/RFE65 with a Texas Speed Chopburcabra( I don?t care how it?s spelled) swapped into it, , the PCM is from an 09 Ram, Tuned by a Florida tuner who posts here a few times (no not N2Speed) and I?m not criticizing the tuner here , The tune it?s self is a good tune , truck made 550RWHP, and how that RFE65 hasn?t crapped it?s self all over the highway is beyond me?? but point is if everything is just right(or wrong) , this thing will jump across an intersection like a 2k hp Twin turbo 481X powered fox body if you?re not hard on the brake, I?ve had this happen a few times with NGC controllers, both stock and Heavily modified vehicles always in Closed loop, 1 I tuned , and few that others have done?.again not saying anything was wrong with the tunes, I?ve never had this happen in a open loop tuned vehicle.

[Chubby Racer]

anyone running open loop 100% of the time? i like the idea of me telling the car the AFR i want all the time vs relying on the o2 sensors... its kind of old school thinking i know.... anyone here running open loop all the time? driving on the street and at the strip?

I'm not sure what you think closed loop fueling is. You "tell the car what AFR to run" and then it uses the oxygen sensors to make sure it's actually HITTING that AFR and adjusts itself to do so. Open looped fueling is no better than a carb where if the weather is foggy or if you go up 2k feet in altitude, your state of tune SHOULD change...but can't. Closed loop can self-correct. Unless you have a nasty, nasty NA race-only setup, there's kinda no reason not to run closed loop at part throttle.

[PurpleRam]

I'm not sure a lot of people understand how to get to 100% OL, it's not just setting rear 02's to max temp.

[LilSick]

wow