pkincy

iTrader: (1)

Well the LS2 402 is in and fired up and now it must be tuned. I will post my progress so that hopefully others can shortcut their process by not repeating my mistakes.

The old tune was for a 401 rwhp, fully emissions controlled H/C/LT car sporting Stage II 5.3 TEA heads, Jet Hots, catted YPipe, LS6 intake, TR 224 on a 114. It idled and ran like a dream (after 39 iterations over months of tuning and tweaking).

My initial tune for the 402 (Stg III TEA 6.0L heads, SDPC 402, TSP 233/233 on a 112 cam and the LS6 manifold) was simply scalling for the change from stock 98 injectors to the Lucas 42s in their now.

The scaling worked beautifully (simple ratio and 1.70 scale) as the car cruises at part throttle with about 4-6 % positive LTFTs. Certainly within the range of a first approximation tune.

Where I missed badly was on idle tuning. The old motor (cam on a 114) idled at 42 kPa and 8 g/cyl. The new motor (cam on a 112) idles roughly (very roughly) at 65 kPa and 9 g/cyl. So my idle tuning is for a way different part of the tables. As a result my LTFTs in closed loop are way positive (15%)

My second iteration (using v 1.5 of LS1Edit) was to drop idle (new spot on the VE table to correspond to the lower vacuum idle) VE 10%, decreased open loop F/A by 10% from 50-75 kPa, and added 2-4 deg of timing in the idle ranges on the timing table. I also did the TPS open to 3% and reset it to zero (see sticky thread in this forum) to get more idle airflow in. Those 2 steps were a minor help.

When I used to tune cars with big cams the first thing I would do for idle tuning is add timing at idle to gain back some cylinder pressure lost due to the big cam and stabilize the idle vacuum as much as possible.

That will be iteration 3 tonite.

I will keep you posted. Also any folks with experience in this process please chime in.

Perry

pkincy

iTrader: (1)

Well nothing I did helped the idle. So I started doing some routine trouble shooting and voila! found that the hose from the passenger valve cover to the TB had been left off allowing massive amounts of air in the TB.

Fixed that and did the TB relearn and cut another 10% off the VE around idle and further evened out the timing around the idle rpm and map values so that any hunting would produce a relatively steady timing/airflow rate.

Good idle now right at 850 on an M6.

Did another iteration with 110% scalar on the idle air tables and found that was the wrong way to go to cure the cruise control effect.

So spent some time doing some clean up on several of the tables around idle and went 85% scale on the idle air tables from the above iteration.

Will load that tonite and report tomorrow. So far the key has been to get the TB set properly and get some timing (I am now at 28 deg at all timing idle cells) at idle. The idle is good but not great (could be the cam).

Now I will attack the cruise control effect.

Perry

pkincy

iTrader: (1)

Ended up with my Throttle Follower Decay table in neutal at 50% of stock and in gear is about 25% of stock and that seems to be in the ball park.

Also bumped my idle from 850 hot to 950. That smoothed things out a lot. Got the IAC tables purring (IAC park at 20 in all temps that count) and idle air in gear at 9.0 for normal temps. Crank VE was multiplied by 85%.

Perry

Blktie8

iTrader: (1)

Following !

pkincy

iTrader: (1)

Car running great (excepting an "open" intermittent in the pcm wiring that I am chasing but that is an install problem not a tuning problem).

Got it smogged today (OBD2 I/M). So that is done.

Now to put in a wide band.....actually 2. I borrowed a new widebank Commander to go with my build your own wide band. Will use both and do some full throttle/power tuning and that think about a dyno.

Perry

Bink

Congrats on the smog, Perry!!

Fun thread ................................

Steve Bryant

iTrader: (1)

If you're putting in a wideband (or two) the first thing that I would do would be to disable closed loop and disable the MAF and get the Main VE table values right for this engine. Then re-enable the MAF and sync it to the volumetric efficiency, then re-enable closed loop. Then you can work on power enrichment and the spark tables. That should make your car very streetable from idle to WOT.

Just a suggestion.

All my best,

Steve

Bink

OR, leave the MAF on and formulate a new VE table as descibed in the thread -> https://ls1tech.com/forums/showthrea...t=ve%2A+tuning . EFILive/ FlashScan outputs VE% and VE PCM (LS1 Edit) - using the same equation in the "Fuel Trim" thread. Then you can fine tune with your WB O2.
FWIW.

pkincy

iTrader: (1)

Thanks for the thread Bink and the suggestion Steve. I will follow both.

I have been looking at NoGo's idle tuning thread (now stickyed on LS1Tuning.com) and used it as a starting point.

However I have had to get the throttle decay in neutral and in gear tables way less than he suggested to kill the hangin idle. That idea came at dinner last nite with an FBud who is an accomplished LT1 tuner, when he said, "My 69 Vette doesn't have that table and it idles just fine." So I took the table down about 50% and the hanging idle is gone. I still have some 2 nd gear 1500 rpm surge however. I will adjust timing and VE to get that out.

But the idea of VE tuning first and than plugging in the MAF is very intriguing. Has anyone ported Joe Georger's VEMaster program to the LS1???? With it you just drove forever and plugged in your .bin file and it would correct the VE tables automatically. Tre Cool.

I own 3 93s, 2 with 383s, so am very used to SD, VE tuning. Right now the car is running very well for only a couple of weeknites and part of a Sat tuning.

Got the PE reset today. Was about 13.2 at WOT across the board on the street. Probably about perfect since those are load conditions, but with it being a new motor and all I dialed it in to 12.3-12.5 just for safety while I am playing with the closed loop settings.

Thanks for the 2 good insights.

Perry

WS6snake-eater

ttt. intersted in how you handled the KS issues????????????

HumpinSS

iTrader: (1)

Hope i didnt miss this but did you change the cylinder volume parameter(stock is .708). This will also help iron out a few issues and at the same time you may be stuck re-tuning the engine

WS6snake-eater

dohh!!!! I sure hope he did too. It sure would make things a lot easier on him.

pkincy

iTrader: (1)

Sure did.

I had borrowed a TB from Bo White while Jantzer took his 2 months to redo mine. So I went back to my TB today. So that will set me back a day or so redoing the idle tuning.

Right now I am about 95% of the way to a good tune. Thanks to the info on this site.

Perry

Blktie8

iTrader: (1)

Hows it feel power wise
ttt

89FormulaLS2

iTrader: (1)

ttt for an update.

pkincy

iTrader: (1)

Sorry about the delay folks.

But the CamaroMustangChallenge season opened March 12 and 13 at California Speedway and I spent 3 days over there....ran 4 and 3 in the big races on Sat and Sun and ran 6th in the inverted race (had to start from the near back row due to the earlier 4th). So that season is starting well with a 3rd overall pts placing after 1 of 8 race weekends.

Also we have been chasing a pcm problem that has kept me from really ragging on the car. Found that. The 110 position ground wires were all there when I first checked, but after further looking the wires to that ground location had broken. So I was running a pcm with an intermittent ground.

The car has also been down for a Racetronix fuel system. That is now in, so I will have a chance to get way more serious this weekend on the final tuning, a recheck of the AFR at PE and than I can give a way better idea of what the power really feels like.

Right now my iteration #14 tune is feeling way good. I got some much needed help form Jeff "Milkman" Creech in NCarolina Land on the cam surge problem. I will report more this weekend.

Perry

pkincy

iTrader: (1)

Came back from Cal Speedway and put the car back in Combination Motorsports for installation of the Racetronix PlugnPlay fuel pump, a couple of guages and to fix the short in the puter ground.

Got the car back and first rule:::::ON'T TRY AND TUNE AROUND A MECHANICAL PROBLEM.

Sorry about the shouting but it is important. I had terrible positive LTrims at idle and low load. Tried my normal; extra timing at idle loads and rpms, less VE at idle, playing with the IAC and throttle cracker tables and really wasn't making any headway. So failing all else I did a good visual on the engine compartment and sure enough the connection from the air pump had come off and I had a rather massive vacuum leak. Actually this was the second mechanical problem that has confounded me as I have been tuning the car. The first was also a loose hose going into the TB. So please observe tuning rule No 1: Don't tune around a mechanical problem, cause it won't work.

Fixed that and the LTrims are all slightly negative, the car idles purring like a kitten and "the beast" can be unleashed anytime now.

I am now on tune iteration number 20 in the last 2 weeks and have not been on a wide band but once. I feel that first is the idle tuning. 2nd is the part throttle tuning. 3rd is the high load, high rpm part throttle tuning. Once all that is completely dialed in than the wot tuning can begin.

I dialed in an extra 3% PE v rpm just for safety this am, but I think I went to far. I will get a wide band on it in a couple of days and get that right on.

I love the motor by the way. What is different is the stroker motor gives you power whenever you want it. You don't need to wait til the rpms are up to go. You hit the accelerator and you move right now!

Perry