Lengthy follow-up for anyone who cares or doesn't and are just bored lol https://store.katechengines.com/174-degree-gen-5-lt-thermostat-p729.aspx Important to note: HVAC off during all the measurements listed below. OE T-stat - 201F start to open, 232F full open (per GM directly) 45mph, steady state, 213-216F ECT, 79F amb 65mph, steady state, 213-216F ECT, 75F amb 53/54mph, steady state, 213F ECT, 107F amb 65mph, steady state, 216F ECT, 107-109F amb OE t-stat with amb temp 86-88F, ECT rose up to 228F during WOT or with steady state and lower gears/elevated RPMs Katech 174-181.2F (174F with a tolerance of +7.2 / -0) 45mph, steady state, 181-183F ECT, 64F amb 55mph, steady state, 183F ECT, 64F amb 65mph, steady state, 185-187F ECT, 64F amb 75mph, steady state, 190-194F amb, 64F amb WOT up to 65/70 ECT peaked 196F with amb temp 64F 45mph, steady state, 187F ECT, 102F amb 66mph, steady state, 198F ECT, 102F amb 70mph, steady state, 199F ECT, 102F amb 75mph, steady state, 203F ECT, 102F amb WOT up to 75mph, 215F ECT, 102F amb Question: After looking at those values, one might ask themselves...with a 174F (+7.2F) t-stat, why are we not seeing lower ECTs? (more so with the warm amb temps) Answer: Active grill shutter strategy (just my opinion based off below) I placed my go-pro on the front bumper and was monitoring the status of the active grill shutters during my drive. Grill shutters are open with vehicle speed 0mph. When accelerating, they would start to close high 20s and be closed about 30mph. When slowing, they would remain closed pretty much until stopped. Obviously, if there is no airflow…no heat exchanged. I have not had much opportunity to mess with measurements and grill shutter status with HVAC on. Wife’s vehicle, our 2nd due in about 2 weeks and coming into winter…not really a priority at the moment. During winter months I am fine with the OE grill shutter strategy, it will help retain heat for heating the passenger compartment. I will revisit the grill shutters in the spring and see what I can figure out going into summer. FWIW, talked with Lew and was hoping he could alter the shutter table (keep OE strategy in Drive and have them open with Tow/Haul engaged…there is no table for him to alter ). So for now, that's that from my side.
I referenced "instantaneous" for 2 reasons. 1. 99% of the YouTube videos (I have watched) from people complaining about AFM and talking about their product bought to disable are "using the DIC as their reference for fuel savings between V8 and V4". Visual representation. 2. I was curious if the DIC displayed value takes into account the cylinder deactivation or not when showing the "real time" economy. Hoping someone might have had an answer to that. I assume yes...but assuming vs knowing are different. This circles back a little to point 1, how it is visually represented to the driver.
How is it being unreasonable to question the "validity" that someone can claim better (or worse) fuel economy with or w/o AFM when there are to many variables to make a true and accurate assessment? Repeatability and reproducibility
I'm stating instantaneous. I'd be hard to pressed to find a compilation of people able to 100% drive the same routes representatively with AFM active vs inactive...let alone have ambient conditions be exactly the same. Too many variables IMHO.
I would like to jump in here... DIC shows really not much of change in fuel economy for me, that I have noticed - (don't frequent the page enough though to really have a solid say, so take this with salt)... I have a theory to this... V8 mode, fuel is being introduced into all cylinder - all cylinder firing. V4 mode, fuel is being delivered into 4 cylinder (2,3,5,8). Moving past all other factors ie increase in engine load working on 4 cylinders vs 8, etc... Would not someone still have the opportunity to be averaging 20mpg within those 4 cylinders as they would otherwise be in V8? You are still using less fuel getting 20mpg during 4 cylinder burn than you would otherwise be getting 20mpg burning all 8. Is this why there is a perception of no gains simply based off DIC? Does the algorithm in the DIC take this into account?
This is what I bought for my 2019 Tahoe 6L80. I wanted to have two on hand just in case, so I wouldn't have the vehicle out of commission. My personal recommendation would be to do the thermostat exchange on a "cold" vehicle, so first thing in the morning after sitting overnight. This is just my paranoid self, I would rather work on materials and deal with tightening/torque specs at amb vs elevated temps. By-Pass Valve – 48.76 - 13511136 6 speed. https://www.gmpartsdirect.com/oem-parts/gm-by-pass-valve-13511136/?c=Zz1jb29saW5nLXN5c3RlbSZzPXRyYW5zLW9pbC1jb29sZXImaT1HQzE1MTE1NSZyPTMmYT1jaGV2cm9sZXQmbz10YWhvZSZ5PTIwMTkmdD1sdCZlPTUtM2wtdjgtZmxleA%3D%3D Found it on Ebay from a local vendor for under $35 IIRC
So I have a stupid question, Can the idle RPM be changed without actually installing one of the canned tunes? From my understanding, the features built-in to the inTune can only be used when installing one of the canned tunes (making alterations to that). Is this correct? Or can I hook up the inTune and make an idle RPM change and leave the OE file/Cal ID and such in the ECM? Follow-up question, different train of thought... I was told by a few that the vehicle can be flashed back to the OE file, take it to the dealer and they would not be able to tell if it had been flashed or not...I find this to be a little odd. Diablo could not answer this question...How is this possible? Doesn't mode 9 clear/reset with a new SW file being flashed into the ECM? If so, all the dealer has to do is a systems health check, quick overview of collected data and it would otherwise shows X value erased/0 values...which in turn would bring the question of the dealer/GM network not showing a history of this from their side. I assume this would be standard practice for any and all warranty work especially powertrain related. Will they bother with this during a typical LOF, no. But I would assume they would research this depending on what warranty work would be getting completed. Anyone have info about that?
Swapped and ready for install. Might be able to get it done this weekend.
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