Can i just disable DFCO? It will only affect my engine braking right?

 

That and you'll get 0.00001 mpg worse gas mileage.

 

that's funny... 0.00001 mpg, funny because it's true and it sounds stupid. Only thing that ever bothered me without DCFCU is I ended up using brakes ALOT more and that got annoying on the Highway or in trqffic when your coasting cause traffic is slowing down and your thinking man sweet I dont have to use my brakes cause my DCFCU is slowing me down.. sweet...

I put a little work into it and got it just right. I was having a somewhat strong re-light I think becuase with 83lb injectors the min puslwidth of 1.0ms was just a little too much fuel for a spikeless return to ignition but I cured that by pulling a huge amount of DCFCU blend timing.. or whatever that was called - it seemed to pull timing during re-light and made it just about unnoticable.

 

can one or both you guys, engineermike and/or dookie454 send me your latest file?

Now that I actually have a turbo that spools, I've noticed the 14.4:1 AFR to 10.8:1 AFR switch at partial throttle...it's like someone put a VTEC in my engine when I wasn't looking because of the instant pick up in power, but then I look in the mirror and I realize it's just a high revving deisel and I should have a stack going through the passenger t-top to direct the cloud of black smoke.

email mkent93@yahoo.com

 

<-- saw that in another post...

Switching from 14.5 to 10.8AFR isnt good by any means, so spending $20 to run full 2bar control sure seems optimal to me.

If you think about the LT1 PCM.. it's plently good using a $20 2bar sensor. If I were building a project from scratch I might buy an LSx PCM however if your car runs with the LTx pcm and your under 7000rpm and ~15psi your good to go.

I would think anything over ~15psi if the 2bar maxes you could add some PE Enrichment and be fine since it's such small amount to carry you safely to ~18psi.

 

I've just switched mine back to gasoline from E85 (would like to run gas until I go to the track anyways and now here in michigan were back to E70 for the winter). With this 2 Bar setup I just scaled my injector Flow Rate by 1.30 to remove 30% of the fuel I was using on E85 and took some timing out under boost. Car started Is running great and only needed one tweak of the VE tables to get the AFR back into shape. I'm still looking for issues and have not found any that cant be fixed....I'm still only running 9lbs of boost though because my clutch wont hold in 4th gear.

 

I am seriously impressed with this thread, a serious congratulations to the guys who hit the send button and began the journey!!!

I went with DFI 4 years ago on my turbo LTx project because I was scared to death of hurting my motor with the turbo from poor PE enrichment tuning.

I always wondered if the maps could be scaled. You guys are basically doing the same thing I do in DFI by rescaling the maps to suit? or when you rescale them do the axis value remain linearly interpolate from smallest to largest? meaning can you add resolution to one portion and take away from another for part throttle tuning.

so from my reading it basically takes having tunercats which i do and a $20 2 bar map sensor to get to 15psi and 7000RPM worth of tuning parameter.. simply great work guys!!!!!!


Chris

 

Made blue comments above

 

the buick world has what is called scanmaster which is a little black box they put on there dash and it connects to the computer.. it reads O2 millivolts, knock retard degrees, iat's, and a sleuth of other good to have information at the push of a button in red led lettering.. it may be something to look into as I am sure a simple splice in to the correct wires in the harness is all it would require since knock sensors, IAT sensor tps voltage is all relatively still the same.. may be something to look into!

Chris

 

There is an LT1 version of the Scanmaster.

 

Scanmaster is ok, either they they seem hard to find or they are too much $? Dont remember why I never got one. Seems like there'd be an easy way to output the same signal the Laptop is allready seeing.. forward it thru serial port to trigger a bright Light on the dash is all I'd like.

I have this tablet PC thing, small size of a bible... logs at 10pts/sec just wish I could get that outputting the Knock Retard signal to a light or something.

 

By the time you have something that will process the retard signal and control an external light you are 90% of the way to something like the Scanmaster...

sounds like its time to organize a group buy....

 

Well we're into the warming stage of winter and Im getting many requests to get a copy of the file so Im posting a link to it here, I thought it was on here somewhere but I cant find it (thought it would be easy to find, sorry about that). I also attached the datamaster log of this LT1_Edit file. Keep in mind all my previous posts were at ~7psi @ 6200rpm and this is the first run since switching to a stock size crank pulley (from undersized) and I expect to have 10psi at 6200rpm, in the one WOT run where I actually had enough traction and held 100% TPS it shows 80kpa at 5200rpm, never made it to 6200rpm.

Anyway this is one of my latest and might be what I have installed, runs good, only been to around 7psi with my 82lb injectors, AFR was around 11.8 around 7psi @ WOT, I max around 6200 rpm.

Idles good, open loop no problems however Im trying to figure out where I picked up some injector shut off (Decel Fuel Cutoff) type symptoms if you are in neutral free-reving around 1600-1900rpm it tends to happen, dont feel it when driving so I havent needed to look into it, but I think the same thing happens at idle just slightly... you problably wont even notice it, it might be something to do with the min pulswidth being slightly too low since the AFR spikes UP when it happens.

Just have to say use at your own risk, take it easy, dont just assume it will work for you, some of my specs are as follows:
1) Siemens 83lb injectors
2) No MAF (SD), never been tested so I have no idea what would happen with one aside from maxing at 5000rpm (pointless)
3) GM 2 bar MAP from an old school 1990? Turbo Sunbird or similar! haha haha
4) decent sized cam (definatly not stock)
5) No 02's since my cam messes them up and leans out idle/low RPM cruise
6) Timing is good for me with 92 octane, 7psi cooler weather havent checked it on hot summer day since last year
7) 3.23 gears for speedo on a Stock 1998 T56 retrofitted to 1996 type bellhousing
8) No EGR, etc

LT1_Edit File:
http://www.mediafire.com/file/12j2qr...8_OpenLoop.lt1 - This runs good but has warm start delay and "exploding to life cold start"
http://www.mediafire.com/file/zo3zwg...6_OpenLoop.lt1 - This one has warm start delay fixed and "exploding to life start" reduced to normal (reducing fuel in Crank AFR vs.... and Prime Pulse tables)

Datamaster Log (I just changed to stock sized blower crank pulley (from undersized) and expecting ~10psi at 6200rpm, this combo is showing ~80kpa at 5200rpm that's all I tested so far: ALSO KEEP IN MIND SINCE THIS IS 2 BAR ON STOCK 100KPA TABLES, WHAT YOU SEE IN THE BARO KPa is ATMOSPHERE, so anything over that in MAP KPa is BOOST! (if BARO shows 53.9KPa that means atmosphere pressure on this new scale is 53.9, anything over 53.9 is BOOST, so 100KPA in the MAP would be approx 14psi-ish, same goes for the LT1_Edit VE tables.. same scale, same values = simple tuning).
http://www.mediafire.com/file/iiddtxd1mjd/Dan_148.uni
.

My 3 WOT runs start around REC# 12402, none are full RPM due to 40% wheelspin and 60% me keeping car safe on a 2 lane road waiting for tires to heat up, but what worries me is at REC# 12692 there is a jump in RPM but not a matching jump in MPH, then RPM comes down just a bit with MPH still climbing a bit, makes me hope it's just sensor error and not clutch slipping (McLeod street twin on an aluminum flywheel), I know RPM error varies quite a bit but also slipping clutches mimick this behavior, as they slip they heat up and grab, just like tires.
.
.

 

To resolve the warm start delay I asked Tunercats about the following tables since I feel the last item to iron out is weak initial "light" during crank when warm. Adjusting tables below (#1 or 2) to increase "initial fuel during first crank" should speed up warm start drastically. I actually think cold "initial light" is so fierce that I may actually lean cold initial fueling just a bit and richen it up in the warm coolant temp tables. Seriously, cold crank ignites on what appears to be under 1/2 second of cranking and it jumps to about 1300rpm then back to 1100rpm idle.. pretty strong ignite in my opinion.

Previously I only adjusted #2, which I think helps but still it has to actually crank before it adds fuel.. I think #1 is exactly what I need to adjust to speed up intial start.. I would assume this goes for all 1995 and newer PCM's including LS1's since they want to make sure the engine is cranking good before adding fuel.

Seems like as cars get newer the more actual cranking you hear before the engine starts.. it appears these settings are 100% responsible for the delay.


Hi Dan,

1. 1st Prime Pulse Width Vs. Coolant Temp. table controls the injector pulse width of the first prime fuel pulse during cranking as a function of engine coolant temperature. Similarly the 2nd Prime Pulse Width Vs. Coolant Temp. table controls the injector pulse width of the second prime fuel pulse during cranking as a function of engine coolant temperature. These tables were in the '96/97 LT1 calibrations. In the '94/95 LT1 calibrations these two tables are combined into a single table (Prime Pulse Width Vs. Coolant Temp.).

2. The 'Crank AFR Vs. Distrib. Refer. Pulse Vs. Cool. Temp.' table sets the target AFR during cranking as a function of coolant temperature and the number of distributor reference pulses.

3. If the engine is still cranking after the time specified by the 'Added Prime Pulse Enable Crank Time Vs. Cool. Temp.' table then another prime pulse is output and the pulse width of this added pulse is specified by the 'Added Prime Pulse Width Vs. Coolant Temp.' table.

4. As soon as the PCM declares that the engine is running the fuel is temporarily enriched as specified by the 'Initial Startup AFR Enrichment Vs. Coolant Temp.' table. This enrichment is then gradually removed.


Best regards,

TC

 

My warm start delay annoyance problem is all fixed!! Starts right up warm like it did when stock FINALLY!

To fix it I had to actually LEAN out WARM CRANK FUEL by doing this:
1) Prime Pulse Width Vs. Coolant Temp
2) Crank AFR Vs. Distrib. Refer. Pulse Vs. Cool. Temp

Initially I thought it was too lean so I was adding fuel and this only made warm start worse, so I went back to stock then removed about 1/2 the values from stock and sure enough when warm starts right up cleanly everytime! No more tapping the throttle to get it to start. Bout time

Cold start also seemed to "jump to life" fiercly so I leaned out a little fuel there too now cold start seems normal as well. Makes sense since I had to pull about 1/2 fuel out of all the other fuel tables at some point.

Now there's nothing left to improve I guess unless I decide to go with a smaller cam so I can turn on closed loop. NAH, it runs too good this way.

Maybe now it's time to move on and concentrate on upping boost?