SladeX

I've worked on my MAF and SD tune to get it ideal as possible. -3 to -5 around the cruise areas.

I've played with the O2 crossover voltages, running pseudo lean cruise settings under the Closed loop tab.

I haven't gotten to pushing the timings up more in the cruise ranges, since I'm currently testing the pseudo lean cruise.

So far I'm treading on 26-27 mpg. I want to bring back EGR into play but need more research to get it working without the EGR being there.

We all love big power numbers, but what are some of your tricks to get more gas mileage via hp tuners?

redtan

iTrader: (5)

Get the engine in open loop and command significantly lean AFR numbers at cruise and part throttle. Somewhere in the 16s or 17s seems to be the most beneficial.

I've also found that playing with injector timing (if you have a good sized set) also helps cleanup emissions and nets some improvement in MPG. It's called end of injector timing or EIOT and there are several threads on the HPT forums about it.

Rise of the Phoenix

iTrader: (27)

Open Loop is no MAF and no o2 sensors, correct? My tune has neither MAF or o2 and my around town and highway cruising afr is in the 16.5 to 17+ range. WOT is around 13.5 and 14.5.

SladeX

I prefer to run with MAF and MAP enabled so closed loop tuning it is.

I played with EIOT and immediately noticed a smoother idle and some more "pep" off the throttle. Did some data logging and noticed no real ill effects on the logs. It's behaving more and more like a stock LS1 car in all situations.

Now do I have to change both tables for EIOT to get the full effect?

redtan

iTrader: (5)

Open loop is no o2 sensors, whether it be MAF or not. The lack of MAF makes it an SD tune, but that has nothing to do with open or closed loops since that's in the oxygen sensors. Cruising AFR is good, but that WOT AFR is insane and I'm surprised you haven't melted anything yet. You should be under 13.0 or right around it...not 14.5 at WOT

MAF or MAP has nothing to do with closed loop, it's what the o2 sensors do. And if you want ultimate control of cruising AFRs and thus mileage you're going to have to disable the o2 sensors and lean out the fueling there. Otherwise, you're not going to get the most mileage out of your setup if the o2 sensors keep bringing back fueling to around 14.7.

Not sure how it is on Gen III tuning, but I think just one is required. Check out the huge EIOT discussions on the HPT forums, there are some good explanations. I only read the Gen IV stuff so at least that part I understand, and I know the Gen III is a little bit different.

So basically that's about it for fuel mileage increase in your tune unless you take it out of closed loop like I mentioned. Injector timing and spark timing are about as far as you can go to increase MPGs without messing with the actual AFR at cruise. Even getting the trims close to 0 is not that big of a deal as regardless of where those are you still are running 14.7 AFR anyway, just with less swings.

Rise of the Phoenix

iTrader: (27)

Thanks redtan. I'm going to get the tune touched up. Those were the readings I was getting when I did a 4th gear pull. I let out once the AFR got in the 14's. It was hard to see exactly what was because I was trying to drive and look at the AFR gauge.

SladeX

I disagree with bypassing O2 to go open loop. Simply put, the sensors can make adjustments for all weather conditions. An open loop tune assumes too much to make it viable over long term variable driving conditions.

Next, I'm already hitting 27 mpg, possibly more now with the pseudo lean cruise. I know this platform can be efficient at cruise without having to be too conservative with your driving style. You just need to know where to look and the EIOT pointer is huge in my books for pushing that extra bit of mileage out. Basically eliminate fuel being wasted due to mistimed valve events. If I can bring back EGR into the mix, I think 30 mpg highway and 16-18 city is quite viable.

redtan

iTrader: (5)

You may disagree, but it's a sureway of getting more mileage. And that's what you asked for right? Tips on getting more mileage? If you don't want tips they why did you ask?

Plenty of people have done OLMAF or OLSD tunes just fine if you know what you're doing. And FYI, o2 sensors don't make adjustments for weather conditions, they make adjustments based on the amount of oxygen in the exhaust stream.

MAF, MAP, IAT and other sensors are the ones that can make adjustments for various weather conditions. If you have those working properly and a wideband to monitor AFR then you can run without o2 sensors and be just fine.

And open loop assumes nothing, it still uses real world data from sensors mentioned above to adjust fueling accordingly. You're confusing it with a speed density tune which is the one that assumes stuff.

SladeX

I'm not running with a wideband. I'm using O2 sensors as indicated in my first post. This means I'm using my O2 sensors and that means I'm using them as intended.

With that said, I asked for tips based on the setup I was using, not for a different direction. My first post describes what I was doing quite well and it asked for other tips along those guidelines. I know full well what MAF, MAP, and IAT do, and clearly indicated I had my MAF and MAP tuning bang on for street.

truckdoug

iTrader: (26)

sorry for the threadjack

@redtan how are you forcing open loop? I tried dropping the narrowband o2's crossover voltages in airflow vs closed loop -didn't help. actually didn't see any change in afr's on my wideband at all

redtan

iTrader: (5)

Pretty simple, you just set the o2 sensor enable ECT to an unattainable value. Thus, they never turn on and you're left with open loop all the time.

Some people have been able to mess with PE enable timing to force the car in open loop at certain points but that's not always reliable.

And depending on the car/PCM using o2 voltages will or will not work. I know on the E38 PCM it doesn't, earlier ones you could.

truckdoug

iTrader: (26)

gotcha. thanks, i will mess around with it. i think my rig is just not aero enough to see much of a gain.

mbray01

if I'm not mistaken on the holdens when they go into lean cruise they go open loop in order to obtain the higher mpgs by ignoring the o2's

SladeX

I just found a huge part throttle/city driving gas mileage improvement. FIX THE DFCO!

After camming the engine, odds are DFCO will not trigger due to the MAP entry range never being hit.

I followed the thread on DFCO on the HP Tuners side and tweaked things according to recommendations. My "combined" today resembled my stock LS1 days... Will take a few more days of tweaking but noticing some improvements in performance. I'm getting improved engine braking now (ie you can feel DFCO cut in).

gofastwclass

iTrader: (2)

I've seen this but when I searched I came up with a bunch of stuff that didn't seem related or maybe it was buried in another topic, do you have a link to the thread?

SladeX

-This has an example modified DFCO
http://www.hptuners.com/forum/showth...-improved-DFCO

-has some of the ideas behind it, Russ K has a lot of ideas on DFCO in many different threads, couldn't find the one I was reading yesterday which said do this to get it working but the above has the settings he said to use.
http://www.hptuners.com/forum/showth...on-C5-Corvette

I did a lot of reading on different DFCO threads to come up with some ideas.

RussK's values for everything for the most part work great.

The only things I modified to fit my car was the kpa entry/exit.

In 2 threads I read conflicting ideas on entry/exit kpa. One was to base off idle kpa and the other your logged deceleration kpa (-5 from lowest for entry, +5kpa of your highest for exit).

My testing has found that deceleration kpa is the better to use. Too low (like stock) and you never really get into DFCO when cammed. Too high and it feels like there is a "delay" when switching back from DFCO to throttle.

My reasoning for any RPM tweaks is based off my cam profile (6.5 degrees overlap + larger throttle body) means the entry kpa will be different than other cars. In my case, the lowest number I hit on decel is 25kpa.

The entry/exit RPM is also a bit different for me as you want to be able to trigger whenever you are cruising and want to slow down BUT don't want it to trigger say when in a parking lot or trying to go bumper to bumper traffic. This means picking something that matches more your drive style and rear end gears and even for m6 cars, what gears you crawl in!

gofastwclass

iTrader: (2)

I'll have to give that a read, I'm always up to learn something new. Thanks.