woody80z28

iTrader: (2)

9.7:1 357 with Vortec heads & LT1 cam
Edlebrock Performer & "Ultimate TBI" mods
TPI pump & stock injectors @ 14psi
$0D mask

I started the tune with LT1 spark table and new cylinder volume...left VE as stock LO5 to start.

It sounds like I have some detonation, but the knock sensor is not picking it up. Any good way to test it? I think I will need to pull some timing since my Camaro is 4600lb with 33s.

The o2 is swinging quite a bit, and the ECM is pulling fuel when it feels like it should be adding it. Is this due to the spark knock? My DIY adjustable regulator would only get me to 14psi with the stock spring, so my heavier one should be here today or tomorrow to bump pressure to 21psi. According to EagleMark's excel that should be 77lbs/hr and feed 310hp.

I should have my wideband on it within a week or so to help sort it out. Just gotta pull it off my Beretta.

Thanks for any and all help. I'm excited to get this thing running better. It should be a fun combination with the 5spd, but right now it's doggy.

woody80z28

iTrader: (2)

My new FPR spring came in so I got my pressure to 20psi. I changed the injector flow rate to 75lbhr in the tune, but the id;e is way rich. From what I've read, I need to change the base injector pulse width constant...but I can't find it in the XDF for $0D. I found "Minimum Sync BPW" with a value of 396.7 uSec, but I don't think that is the correct place...because it should be about 135 according to the other threads.

Ronny

iTrader: (1)

Test the knock sensor by banging lightly somewhere on block or headers with small hammer. Should show up immediately.

the "table" might be called BPC or BPC vs MAP(VAFPR).

Can you post LT1 spark table? I hear Vortec needs less SA. I would use LO3 table but compare the two.

woody80z28

iTrader: (2)

Here is the table I was given as a baseline. Yes, it does have more spark than the stock L05 truck table.

400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2800 3200 3600 4000 4500 5000 5500 6000 6500 7000
25 KPA 18 22 26 29.0 31.0 33.0 35.0 36.0 37.0 37.0 37.0 38.0 38.0 38.0 38.0 38.0 38.0 37.0 37.0 37.0 37.0
30 KPA 21 25 29 30.5 33.0 35.0 38.0 39.0 40.0 40.0 40.0 43.0 43.0 43.0 44.0 44.0 44.0 43.0 40.0 40.0 40.0
35 KPA 22 26 30 30.5 32.5 34.0 37.0 38.5 39.5 40.0 40.0 41.0 43.0 45.0 45.0 46.0 46.0 46.0 42.0 42.0 42.0
40 KPA 21 24 26 28.0 30.0 31.0 34.0 35.5 36.5 38.0 38.5 39.0 41.0 42.0 43.5 45.0 45.0 45.0 41.0 41.0 41.0
45 KPA 20 22 23 27.0 28.0 29.0 32.0 33.5 34.5 36.5 37.0 38.0 39.5 40.5 41.5 42.5 42.5 42.5 39.0 39.0 39.0
50 KPA 19 21 22 25.5 26.0 27.5 30.0 32.0 33.5 35.0 36.0 37.0 38.5 39.5 40.0 40.5 40.5 40.5 38.0 38.0 38.0
55 KPA 17 19 21 24.0 25.0 26.0 28.5 30.0 32.0 34.0 35.5 36.5 37.5 38.5 39.0 39.5 39.5 39.5 37.0 37.0 37.0
60 KPA 15 17 21 22.0 23.5 24.5 27.0 28.5 31.0 33.5 34.5 35.5 36.5 37.5 38.0 38.5 38.5 38.5 36.0 36.0 36.0
65 KPA 12 15 19 19.5 21.0 23.0 25.0 27.0 30.0 32.5 33.5 34.5 35.5 36.5 37.0 37.5 37.5 37.5 35.0 35.0 35.0
70 KPA 9 12 16 16.5 18.0 21.0 23.0 25.5 29.0 31.5 32.5 33.5 34.5 35.5 37.0 36.5 36.5 36.5 34.0 34.0 34.0
75 KPA 6 9 13 13.5 15.5 19.0 21.0 24.0 27.5 30.0 32.0 33.0 34.0 34.5 36.0 35.5 35.5 35.5 33.0 33.0 33.0
80 KPA 3 6 9.5 10.5 13.0 17.0 19.0 22.0 25.0 28.0 30.0 32.0 33.5 34.0 35.0 34.0 35.0 35.0 32.0 32.0 32.0
85 KPA 2 2 6 7.0 11.0 14.5 17.0 20.0 22.5 25.0 27.0 29.5 31.5 31.5 33.0 32.0 34.0 34.0 31.0 30.0 30.0
90 KPA 2 -1 4 5.0 9.0 12.0 15.0 17.5 20.0 22.5 24.5 27.0 29.0 30.0 31.0 31.0 31.5 31.5 30.0 28.0 28.0
95 KPA 2 -2 2 4.0 8.0 11.0 13.5 15.5 18.5 20.5 22.5 25.5 28.0 29.0 30.0 30.0 30.5 30.5 29.0 28.0 28.0
100 KPA 2 -2 0 3.0 7.0 10.0 12.0 14.0 17.0 19.0 21.0 24.5 27.0 28.0 29.0 29.0 29.5 29.5 28.0 27.0 27.0

I tried running the stock spark table and it was very sluggish in comparison.
And when I rapped the engine mount with a hammer the ECM did pick up the knock.

woody80z28

iTrader: (2)

I don't see any BPW vs MAP tables. There are some correction multipliers vs MAP and VE vs MAP...and an "Async short BPW offset vs BPW" table that is set at 396.7 uSec for the whole thing...which is the same value as the "Minimum synchronous BPW" constant.

jahblah

awesome setup man. i always liked the 357 vortec combo

Ronny

iTrader: (1)

seems like way to much timing for Vortec heads. Search Fast355 for "spark advance". Or pm him. He is the one in the know for Vortec SA.

You may not have any. That is for VAFPR. You have a "constant" then for BPC.
What you referenced is a mod for BPC. Mods are there for almost every sensor/table like voltage, coolant temp, etc.

woody80z28

iTrader: (2)

It's more timing that the stock table, but it definitely has better throttle response. I'll search Fast355 and compare.

So the "Minimum synchronous BPW" must be my constant then I guess. I've already changed the injector flow rate from 61 to 75lbs/hr according to EagleMark's excel spreadsheet. But the BPW value of 396.7 just seems way out in left field comparing it to other threads I've read.

Ronny

iTrader: (1)

"Mod" is a modification to a setting. Modifier as in changing coolant and voltage and intake air temps are ones that come to mind.

When I ran 7747 is just asked for BPC and I plugged it in.

value 396 is not it. 396 may be minimum BPW in uSEC. Not BPC.

I have a calcuulator for BPC uses inj size and FP and CID. What is your #s?

What ECU are you running?

woody80z28

iTrader: (2)

7427 running $0D.

357ci
stock 61lb injectors
20psi

I can post up my bin and XDF for you to look at and find BPC. I don't see it anywhere.

Thanks!

Ronny

iTrader: (1)

post xdf. My company may block it however.

woody80z28

iTrader: (2)

Here it is. And the stock bin so you have something to reference.

Rename .doc to bin and .mp3 to xdf.

Ronny

iTrader: (1)

How to rename to .xdf? For sure I cannot open .bins. Prob cant do .xdf as I do not have tunerpro at office.

You can search TP for "BPC". Likewise same on search for any other term. I once misplaced one and found it with search.

1995K1500

I don't think the $OD mask has a provision for BPC. You input injector flow and cylinder volume the ECM runs the math.

woody80z28

iTrader: (2)

Well, the o2 was showing very rich and the ECM pulling some fuel with my injector flow rate at 75lb/hr so I upped it to 85 as an average with another FP calculator I found. It brought the idle down a little leaner and the BLMs are fluctuating between 115-145, but it seems to run better open loop...so I'm wondering if the o2 is a little whacky. I plan on installing my wideband this weekend.

As it sits though with the flow constant at 85lbs the light throttle seems a little better than it did at 75, but the idle can be erratic wanting to stall on one drive and idling high at 1400rpm on another drive. And getting on the throttle harder it bogs/stumbles where the 75lb constant felt better.

So the plan for now is to set the injector flow constant back to 75lb/hr and put the wideband on it and do some more logging. Maybe even disable closed loop I'm thinking...

Fast355

iTrader: (2)

Those are automatic transmission spark advance tables for the LT1, looks like a B-car. The Vortec heads are nearly identical to the LT1 cast-iron heads on the B-car, however your timing map should be more closely based on the LT1 F-car with Manual transmission. The manual transmission loads the engine differently than an automatic transmission. I would look at PE settings as well as get the engine enough TPS AE to make it responsive and enough MAP AE to smooth the transition to main fuel. If you are getting alot of tip-in knock, chances are it is lean.

Even in my heavy, tall geared G-van with 3.08 gears and a tight torque converter, I had no issue running 32* total timing all in by 3,400 wihtout knock counts.

woody80z28

iTrader: (2)

Interesting. It does feel a little sluggish just as I let the clutch out at ~1200-1500rpm.

Where should I look for a LT1/6spd spark table? Or would there be a way to find an L31/5spd table that would work?

I spent today doing a little logging before tearing it down to swap out lifters (new stock LS7 in for used L31), and when I left it idling at the landfill for a few minutes it stalled. The BLM went down to 90 and it choked out. On restart it idled at 1900 gradually coming down to 1500 (over 100 IAC steps) and then after a couple minutes driving it was fine.

Long day today, but I'll post a link to the logs tomorrow. We got pounded with snow today, so getting the wideband out of the Beretta and in the truck probably aint gonna happen tmo either. I'm curious as to why it's acting so strange. I never had this much trouble with the $A1 and the Beretta.

woody80z28

iTrader: (2)

Found an LT1/T56 table after some digging:

https://www.thirdgen.org/forums/post...04-post11.html

woody80z28

iTrader: (2)

Wow it really is rich. Idling at 10.5 - 11:1 on the wideband. Spikes to about 17:1 when you let the clutch out or get on the throttle in gear, so I'll have to add probably quite a bit of AE. I installed the wideband output to the B16 pin for the $0D xdf, so when I get my laptop on it the wideband reading should register.

I put that manual trans spark table in a new BIN, but didn't burn it yet. It is a lot more timing in most circumstances than the iron-head LT1 table I was using...so I'm a little tentative to use it. Seems like a lot of spark for a heavy truck. What I'd really like to find is an L31/5spd spark table since it's closer to my baseline. Mine has the same heads, slightly more cam, slightly more compression and the gear ratios/weight would be a lot closer than an F-body.

woody80z28

iTrader: (2)

I implemented the T56 spark table and just brought the WOT timing down to 31 and haven't picked up any knock. Hopefully it will stay that way even when towing.

I also changed my injector constant to 79lb/hr and took some VE out of the idle cells and added an extra 25% AE everywhere. The driveability is great! By far the best it has been. There is still some work to do on the VE tables, but the BLMs are staying more consistent and I've felt very little hesitation under any driving circumstances. The low end is greatly improved, which is more what I was expecting. This thing should be a torque monster down low and it was sluggish until 2000 until my last round of changes. I love this wideband, it helps so much!

trona

I have had the same problem with my 383 gm crate motor with cast iron heads. Tried pulling out all the knock and ended up with a undriveble truck. Ended up leaving the timing in and letting the knock sensor pull it out.
I table lt1.gif says it is for aluminum heads. It is my understanding that aluminum Vortecs will take a lot more timing do to heat dissipation.
I would love to get to the bottom of this though . Look forward to see what the solution is.
Toyota land cruiser with a GM 383ht crate motor, nv4500 5 speed, weight 6800lbs.
Thx Dave

woody80z28

iTrader: (2)

Didnt end up being spark knock like I thought it was. Knock sensor works, but never registers during driving, just at start up and with a hammer on the engine mount. I had a couple noisy roller lifters so I replaced them all with new.

Plan on doing some more datalogging tomorrow. Thinking about going full open loop too actually...we'll see how it goes.

Fast355

iTrader: (2)

What did you put on that rig to make it weigh 6,800 lbs. A 2500 Diesel quad cab Ram barely weighs 6,800 lbs.

As for the heads, my cast-iron vortec tunes all seem to like around 28-32* of timing above 3,400 rpm no matter what they are in. Truck, Van, Suburban, RV, doesn't seem to matter. The aluminum vortecs can tolerate a touch more compression and 30-34* of timing and run full timing on 89 octane vs 93 w ith the regular cast-iron heads. Speaking of which to run more than about 22-24* of timing on a ~9:1 or greater compression cast iron vortec head engine you MUST run 93 octane.

woody80z28

iTrader: (2)

Are you talking total WOT timing? Cause the tune on it now has 31* with 9.7:1 on 87, and the truck is almost 5000lbs with me in it.

Per your recommendation I'm running the LT1/T56 spark table (with a few degrees pulled out at WOT) and the knock sensor isn't picking anything up on 87. My quench is on the tight side at .034" which may help a little. But from your reply it sounds like I should be pinging like crazy.

morgsie

iTrader: (1)

I was hoping on running 91 octane on my 10:1 355 w/ iron vortecs... anything above 91 is hard to find up here. My builder said to run it on 87 to boot...

woody80z28

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I found a stock L31 Vortec truck spark table and the timing is very conservative...like 20* at WOT, and those engines are only 9.4:1 (although their quench is not as good as mine with their dish pistons. I went D-dish for best possible quench.

woody80z28

iTrader: (2)

Found a good graphic of a stock Vortec truck:


And here is another modified Vortec TBI truck combination with fairly conservative timing. My F-LT1/T56 table has a LOT more timing everywhere, but I've seen quite a bit of variation from 20-30* SA at WOT on other truck setups.

woody80z28

iTrader: (2)

Tried out the stock Vortec table and it's a DOG.

40ozthreat

Thats an oldie SA table. I have upped it quite a bunch, especially in the low map. Its important to remember that most people refer to total spark for vortec heads as 32-34. This means total timing around the peak of your torque with no vacuum advance and EFI that would be the 100 kpa column. That SA table had a nice shape but was lacking advance.

In one of my aggressive tunes I was running about 38 degrees actual as early as 2k (80 kpa I'm at altitude). No knock counts and she was running great. Went to get emmissions and she was a little high on Nox, pulled timing and I got the "fast pass".

Guess my point I'm trying to make here is if you know your knock sensor is picking up knock and you know how to recognize an unhappy engine, don't be scared to explore in the direction where it feels good. Being a little over zealous won't kill you. The high Nox was most likely from high temps from too much timing which was ran for over a year. The motor is still fine and I keep improving and am not unhappy with its performance. On the flip side don't go max out your high map SA right off the bat, but do small incremental increases till you notice a decline in performance or knock counts and back off a few degrees.

Fast355

iTrader: (2)

Total @ WOT and I am talking about knocking at sustained load in hot weather. It may not knock in cool weather, but strap a trailer behind it, after idling in bumper to bumper traffic with the a/c on, accelerate at heavy throttle up on an on-ramp into 3rd gear and that much timing will start rattling things nicely on 87. On 93 it will be fine though.

Fast355

iTrader: (2)

Here is what 29* @ 3,800 rpm looks and sounds like on a L31, I would post the spark map, but since I am running an 02 PCM and code in it, the spark table is based off of MAF flow and RPM instead of MAP. 1997 Express van with a 5.7, LT4 production cam, 1.6:1 rockers, and MPFI spider, along with the 02 intake ducting and 85mm MAF. Runs phenominally better than it did in 1997 with the stock L31. Has a S10 converter and stock 3.42 gears, but pulling around 6,200 lbs.

http://www.youtube.com/watch?v=7SgptElOCpY

woody80z28

iTrader: (2)

Wow, that's hustling for 6200lbs! So I take it for that much spark you run 93. Stock 9.4:1? And your cam must bleed a little more cylinder pressure than my stock LT1 cam.

This weekend I put my previous spark table in and it's much better again. All is well unloaded at ~4800lbs on 87 during fall in NY. A bit different than summer in Texas I'm sure.

I'll see how it is in the summer, but my truck is my winter beater and the drywall or car hauler in the summer time. If I need to run 93 when pulling in the summer that's fine. I wouldn't want to give up the power & efficiency of the added spark for the winter months. I'll keep my eye on it if I'm hauling something heavy this winter on 87.

morgsie

iTrader: (1)

Well that puts my mind at ease a little bit. It does get hot here, but not like down there. The car weighs 4,200 lbs and I won't be towing anything in it. I guess when I get into tuning it I can experiment with different grades of gas. I like Shell 91 octane up here because it doesn't contain ethonal unlike the other distributors.

woody80z28

iTrader: (2)

Interesting event last night...truck would not start because it was flooding out when cranking. It was about 20* out, probably the coldest it has been when trying to start it. I let it sit and then held the throttle wide open and it started and after about a minute it ran fine. This morning it was a little over 30* in the garage and lit just fine.

My idle is still a little bit rich, but I'm not sure if that would have an effect on cranking fuel or not. I'm guessing there is a table somewhere I should be pulling fuel from at low temp.

Ronny

iTrader: (1)

There are several you may want to look at.

One is the "crank" fuel, then the choke fuel, and the modifier based on coolant temp. The modifier is to open loop after choke times out.

woody80z28

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Modified the crank table and it was fine for a few days and then flooded out on a hot restart at 50* ambient temp. This time I had the laptop with me and saw the CTS was reading -40. After I tightened the ground it was fine.

Got 14.9mpg on a 180mi trip where maybe half was straight highway.

40ozthreat

Check out your other logs to see if the cts is an ittermittant issue. The CTS is critical to speed density and greatly effects timing and fueling. In general it adds fuel and timing when cold so now you may not have enough spark. I always look at the spark advance history table when i am adjusting SA and that is where you want to pay attention to the total wot timing.
Sounds like you are getting closer, just dealing with thise typical build issuew that make thus so fun. 15 mpg may be good depending on gearing and driving habits. I average about 16 have gotten up to 19 and towing at 75 have gotten as low as 9.

woody80z28

iTrader: (2)

Did it again. And the grounds at the tstat are good. Any ideas what else it could be? I was thinking maybe a broken/frayed wire? Bad connection at the sensor itself?

I would guess that a bad CTS wouldn't swing from 200 to -40 and back in a sec. Am I right? It generally stays at temp and then swings too low for 1-5min at a time. Sometimes longer. I looked through my last couple logs and sometimes it would dip to 80 or 130 instantly when it was at ~200. On flooding restarts though it's got to be giving a really cold reading.

xch3no2

WOT during crank is "clear flood" mode.

CTS normally become less sensitive with age & fail open (-40*), savvy guys keep one around. Intermittent failure is less common, but possible.

The CTS connector can develop corrosion inside where wires crimp to the pin connectors, actually a common problem in damp or salty environments.