Hard to say. The ideal to me is where the main ECM ground point is. That's not to say your setup won't work... Just that I'd go for the best possible.

 

Star point grounding is ideal.
This is a good video actually just about anything this guy teaches is great info, his name is Andy Wyatt and he was the founder of the ecu called Adaptronic, it’s long been sold to Haltech but I believe he’s still an engineer for them, if I’m not mistaken he also won awards back when he was starting off for creating the first software that not only autotuned VE but also ignition tables.

 

Those are some relatively complex electrical concepts. To be honest when I went to Purdue University for engineering, electrical engineering was the one class that was really a challenge for me.

I think I generally understand the concept of what he is saying, but it's hard to decide if I'm good how I am, or not... The current ground connection is on the metal dashboard support frame, which I believe is one piece that goes all the way across both sides of the dash, It is bolted, thus grounded to the firewall. I know I have the woven copper grounding strap from the fire wall to the back of the passenger side head. Then the heads and engine block have a couple other large sized grounding wires connected to them. Does that mean I'm good?

I see there is an O2 sensor ground on the connector schematic above, but the factory O2 sensor is a single wire and grounds through the block... What is that for? Or is that what I should be connecting my signal ground to for my WB output??? It's called out and has a wire color, but I wonder where that goes??? there are a few other grounds coming out of various connectors on the ECU, maybe I move my ground over to wherever those are connected to. Probably the same steel dash frame, just on the passenger side...

In the end I should just be able to try it how it is and test it. If the values I see coming up on the gauge match what is coming up on the data stream from the car in TP, then I'm good, right?

 

The "O2 sensor ground"... this goes to what I was saying about making sure your grounds are excellent.

The "O2 sensor signal ground" coming out of the ECM is just tied to chassis/engine ground, so it's only an "inferred" ground reference since the single wire O2 grounds itself to the exhaust manifold. It's a recipe for a ground loop if the electrical path from the O2 sensor body to the main engine ground point for the ECM isn't the greatest. The factory 1 wire sensor grounds itself through the exhaust system, so the ECM assumes that the sensor ground is the same ground as main chassis/engine ground.

So people with ground problems on the NB O2 that the ECM relies on... that can become problematic as the ECM gets an erroneous reporting out of the sensor, which causes it to make errors in the fueling corrections. Which is why I often recommend a 4-wire sensor like the AFS-75. But I also tell them to tie the sensor ground back to the main ECM ground, for the reason I described above. At that point, the "O2 sensor ground" circuit actually sees the true O2 sensor ground.

Now, the WB O2 has a sensor ground, so it isn't reliant on the sensor body, and since the ECM doesn't use this to run the engine, this won't make the engine run any different.

But the issue I'm trying to ensure you avoid is that the WB O2 gauge is going to put it's own separate 0-5V reference voltage into the ECM at what's normally a MAP sensor signal return. That hypothetical MAP sensor would have had its own sensor ground allocated to it, along with its own the 0-5V reference the ECM would have sent out, so it's a closed circuit unto itself.

So if your WB O2 gauge ground and WB O2 sensor ground are different than the ECM ground, that 0-5V reference may come in a little different, which means the ECM will interpret it differnetly, which means Tunerpro will get an erroneous reporting from the ECM, which means you'll see an inaccurate A/F ratio displayed (since you're likely going to simply input the lambda curve into TP from the WB datasheet).

 

@ULTM8Z You mentioned previously you would be able to tell me how to get TP set up to handle my WB data once we get to that point. I got everything all wired up tonight, as well as the MAT which is now an IAT sensor in the plastic intake Y pipe. I selected the AEM Linear AFR flag In the Wide Band folder in TP. I am seeing it show up on my digital dash while logging, but I do not see it in my actual data log data I output to excel... Also, what is on the Dash is not right. I have the equation to use to go from 0-5V to AFR, just not sure where to enter it. Or how to get it to show up on my excel outputs from TP.

It would also be nice to be able to convert the NB o2 sensor mV reading into AFR is that possible. Or are the NB O2 'counts' the data I should be manipulating and interpreting?

 

You might want to use my .adx file. It's already set up for an AEM.

I'm attaching it here, but you'll need to change the file extension back to .adx.

If that doesn't work by itself, I'm also attaching the .xdf file I'm using as well. Again, change extension back to .xdf

I don't think you can convert the NB to a useable AFR reading. It doesn't that kind of fidelity when it gets far away from the 450mV center voltage.

 

Great thanks I'll give those files a try.

So you're saying 450mV is 14.7? I guess that is how the rich lean indicator determines that. Maybe I'll just take the difference from that to see gauge how high or low it is, not super helpfull though...

So I'm now getting into my iterative VE tuning. At first I read you are supposed to multiply the old blue based on the BLM and the int at the same time, but I read somewhere else that it's easier to tune everything first with only blms, then work on ignition timing, then go back lock your blms so the min amd max are both 128, then fine tune only with the int values. Is that the right process to take?

 

That's a reasonable approach. Lots of people seem to have different preferences.

 

So sadly I’m no guru on the 7730 $8d ecu but ran it for years, the way I use to do it was first setup all my sensor data and out put data, like your air temp sensor and injectors, once everything is calibrated correctly or to the best of your ability (especially with injector data) I would lock it in open loop and compare WB to commanded AFR, then it’s just simple math, add to remove the percentage difference to the VE cell, oh yeah don’t forget to turn off PE also, basically you don’t want anything adding or trimming your PW while collecting data to make changes to the VE table.
One thing that I hated about tuning the 7730 was all the stop change flash retest, I eventually did the NVsram module so that I could just flash live through the ob1 connector, later moates came out with I think it was called the ostrich? You could just leave it plugged into the ecu and flash live to it then once you had the tune good you could burn the chip.

 

From post #38: Alright so I'm trying to get into the actual VE tuning, and I want to make sure I'm doing my calculations correctly before I go starting to make a bunch of changes... Does the below look right? I've seen some where you use just the BLMs and some where you also multiply by the INTs, which should I be doing, or if different at different times, when?"

From post #57: "So I'm now getting into my iterative VE tuning. At first I read you are supposed to multiply the old blue based on the BLM and the int at the same time, but I read somewhere else that it's easier to tune everything first with only blms, then work on ignition timing, then go back lock your blms so the min amd max are both 128, then fine tune only with the int values. Is that the right process to take?

Welcome to the world of "trying" tuning a performance engine with an antiquated EFI technology. Good luck!

Here's my educated opinion:

At first, yes get the BLM grossly tuned. I mean, make sure they don't peg either way. But don't try getting them obsessively to 128. 15-20% margin is ok for now.

After, It's more accurate to tune VE table based on INT averages. The INT is quicker to react and will keep bouncing from richer to leaner. It's how the INT works. Having said that, VE tuning requires lots of patience. You have to make sure you are comparing data that is consistent. That means, CT, MAT, Atmospheric Pressure, Outside Air temp, Voltage and Gasoline are of equal value from datalog to datalog. Otherwise you'll chase your tail, believe me.

The BLM's are a pain in the a**. Depending on how they are set up they can be slow to react, create inconsistency within BLM cells and mess up your OL via SAM (Stay Alive Memory). I would disable SAM, BLM and Prop Gain and tune on INT only. Having said that, the fact your O2 sensor only monitors one bank and your WB monitors the other bank is adding inaccuracy to an already inaccurate system.

Modifying O2 voltage windows can be very tricky has it's only based on MAP values. With $8D, idle 02 voltage is managed with other parameters when in idle mode. So that gives you some adjustability in CL when in idle. Remember that the ECM will constantly going from rich to lean in CL operation in somehow fast cycle. The idea is to achieve O2 windows targets and also catalytic converter efficacy. With pure gasoline it means 14.7:1. With other type of gasoline, like E10, E15 and E85, the ratios are different.

For WOT tuning, you will need to monitor both banks as the ECM is shooting in the dark. If you don't disable BLMs, at least isolate BLM Cells 12 to 15 so they can only be entered when in PE WOT. That way, BLM won't affect fuel delivery in WOT yielding consistency.

I would work on ignition timing early in the game. Again, these system can be quite inaccurate. They can be off by 4-6* from commanded SA to real SA at crank pulley. I am surprised your engine only requires 6*. One would think you'd need 10-12* initial advance. Also, the Knock Retard routine can be frustrating and inaccurate pulling timing on false knocking.

In any case, you are in for a ride. I suggest, if you have the budget, to contact @Tuned Performance . He's tuned many engines over a few decades with GM old EFI system.

Peace

 

Antiquated systems... yeah I'll say.

If it wasn't for TunerproRT, the Ostrich, and the S_AUJP files that both provides WB capability with TunerproRT as well as bringing out all of the obscure fueling parameters for AE stuff like that, Not to mention access to GM's 4th LT1 calibrations and the valuable knowledge dispensed on this forum... There's just no freaking way I would have gotten my 7730 dialed in to the extent it is now, especially with an intake as challenging to tune as the Miniram.

It basically took all of that to overcome the limitations of the 7730.

 

That says it all. I'm sure you forgot to mention the thousands of hours dedicated to it!!!!

If I'd do another restomod in today's environment. No way I would go with old EFI systems. Not worth the hassle, no support and inaccurate.

Cheers

 

Oh you have no idea.... lol...

Think about this... I put the Miniram on my ZZ4 in 2000 I believe... and after a while I got it to run "pretty good" as a result of the benefits of the 7730 support I mentioned above. I think most people would have been satisfied with it.

But if you told me even just a year ago that I'd have it running like it is now, I'd have said no way..... 25 years later!! I literally thought I had reached the limit of the 7730. It was just dogged determination.

But I agree, if I had to start from scratch, no way I'd go with this system.

Matter of fact in 2021, the ZZ4 spun a rod bearing and I had decision to make. Stay with the Gen1 SBC and go with a 383, or scrap it all and go LS. By that time I felt I was so familiar with the 7730 and rest of the car was already set up for Gen1 (and I didn't want to redo it all), I just went 383. That said, I don't regret the decision at all... it has more than enough power for what I do with the car.

And I'll admit, there's a certain level of satisfaction after having achieved it.

 

Modern EFI, old school tech such as what's on the table here or a simple (not so simple really) carburetor with a weights and springs distributor, that satisfaction is universal.
That there's a community of like minded thirdgen enthusiasts that are onboard with advice and assistance is what it's really all about.
Good luck to @raptere .

 

Oh great, you're all making me think I made the wrong decision tuning myself with the ECU and equipment I have instead of spending three grand on one of the new Holley computer systems.... I do truly appreciate all the help and support you guys are giving me as I work through this!

So, I'm using the new files so I can see my WB readings, which after correcting the equation in the ADX is working correctly. Just took a nice long drive and data log, about a half hour.

Problem now is my new data log outputs to Excel now have a Main and a Find BLM value... Which should I be using for right now. Or is it as it sounds? Use the main ones till you're close, then tune again with the fine, then finish by tuning with your INTs?

 

Honestly being that I used to make a good amount of money tuning cars for people/customers I saw the writing on the wall years ago, tuning is a thing of the past and I foresee most ecu’s being an fully autotune setup and these will handle most people setups, dyno tunes will be left for max effort cars.

That being said the 7730 is a good ecu and actually I used it for many years with great success, when I decided to twin turbo my car that’s when I decided to switch and not because it wouldn’t work but because of all the extra inputs and outputs I wanted otherwise I would have kept it.

It’s crazy people still come to me asking what ecu should I get and can you tune it for me, I’m like I don’t do that anymore so just get like a terminator with the handheld of ease of setup and autotune of like Fi-tech.

Personally I’ve never tried the Fi-tech but for the price of the tpi setup how could you beat it.

If your doing a full on race car obviously I wouldn’t be recommending a Holley,Aces or if-tech. This one is going to be controversial because some people love the terminator but to me it’s still just a budget ecu.

 

Since you have my adx file, I may as well give you my VE tuning tool... The instructions are embedded in the tool.

The BLM update rate is every 2 seconds in the factory calibration. So as long as you hit each cell several times while fully warmed up, you'll get a pretty decent. sample.

 

ULTM8Z I have a question, so I just looked at your ve tool, it reminds me of the one I did years ago on here somewhere but I did the histogram in ve not blm, won’t it be better to first start as I suggested by locking in open loop then log the different between commanded afr and actual, then go into closed loop and do the same with your tool?

I know I haven’t been in that $8d game in a long time but is there a reason why my logic is wrong?

Also your a legend for keeping up with it and helping the community.

Thank you
George

 

Thanks. Just doing what I can... I know I learned A LOT from folks who don't frequent the DIY board as much these days (and we all know about RBob sadly now)... so just trying to "pay it foward" so to speak... hopefully I can help others.

As far as your method or my method (or someone else's), I don't know that one way is wrong or right vs the other... just different ways of getting to essentially the same answer.

I'm actually kind of in between right now... "quasi-closed loop" as I call it.

https://www.thirdgen.org/forums/diy-...osed-loop.html

Once I got the BLM's dialed in, I made the changes described in the above link and then effectively locked the BLM's to 128, and let the car run on the INT. I get very much more consistent results from one day to the next.

 

Wow! I had no idea about the histogram feature in TP! I was purely using a massive excel output from the data log and spend all day sorting and manually calculating averages and copying the info over into another similar spreadsheet. But with the history histogram feature, I should be able to do this in minutes instead of hours!

One question though, should I be running the Historical average, or Running average. I ran both and do get differences of up to about 25 in a few places. The Running average seems to settle out, whereas the Historical Average seems to keep significantly changing the values all the way through the log. It's cool how you can watch it real time in the graph as it is tweaking the values. I ran it at 15x speed to save time.

Also, why is your BLM Target 126? Shouldn't it be 128???


Historical Average

Running Average (Seems Smoother, Moved less near the end of the log)

 

Running avg vs history avg...

https://www.thirdgen.org/forums/diy-...-question.html

That in the VE tool is selectable. You might make the target BLM 132-134. With a single O2 sensor, if the BLM's tend to be on the leaner side of 128, that means the ECM is adding fuel, which means the side of the engine w/o the O2 sensor is at less risk of actually running lean. For a performance engine, I'd prefer to be on the richer side of stoich.

 

So, I feel like I keep finding different discussions and threads on different tuning topics, but never have I seen a start to finish list of all the different tuning processes in the ideal order...

I'd like to attempt to do this then have you all add to the list and/or correct the order of tasks. I would also like Identify at what point you should move on to the next step. It seems like a lot of steps you can get wrapped up in striving for perfection, where it isn't possible, or frankly necessary, since a later step, will fine tune, the coarse tuning you started in a previous step.

1. Learn about methods of burning chips, order equipment, select and learn about your choice of software (Tuner Pro RT in my case) burn your first chip, just changing something simple like idle speed for proof of concept.
2. If making significant changes like I am, set all the critical engine parameters, cylinder volume, number of cylinders, injector flow rate, match spark advance base distributor setting, with actually physical setting of distributor with brown wire disconnected.
3. Start with a known tune, either a factory one that is as close as possible, or one for a more similar set up, but only from SOMEONE YOU TRUST! Using a random bin with mistakes CAN DAMAGE YOUR ENGINE!
4. Disable PE, then run long data log with varying driving style to try to cover wide range of vacuum levels and engine speeds, then interpret with your program of choice using the main BLM values and tune your VE tables. Repeat this process until all BLMs are within (120-136, +- 8 from your desired?)
5. Then what?

I know I need to tune my ignition tables, my PE, is there also a thing called AE? Then go back and fine tune my VE tables using my INT values? Then what else for fine tuning other details and parameters? Is there a logical time once you have a well tuned upper VE table, that it makes sense to expand that information onto the extended upper VE table? Do most people do this at some point? I know I need to play with my TCC settings too, because with this engine it is lugging below maybe 40 mph under light throttle, but when the TCC appears to be locked...

I'll continue to add to and update this list as I learn more or get more feedback...

 

All good stuff, years back I wanted to do the same and basically make a map or tree of where to start more for myself so I wouldn’t miss steps when tuning a car.

I’ll add my two cents, some things need to be kept in mind.
1. An engine computer is just a calculator, in the 7730 for example it’s just doing the speed density formula for fueling. The ecu takes all the inputs like iat, mat, o2 and is like plus this and minus that, spray the (outputs) injectors x amount. Knowing it’s doing math you wouldn’t want to be putting the wrong values in to calculate because the final result will be wrong. Inputs and outputs to the ecu processor are fed in digitally, so for example the tps is an analog signal that gets fed into an adc (digital to analog converter) chip on the circuit board which then get sent to the central processor to do its math, some sensors on some car/engines are already a digital signal and don’t need an adc so it goes directly to the processor.

2. Okay we know some stuff now, so this is why the input and output stuff needs to be addressed first, injector data like voltage offset values and small pulse width table, iat, mat and ect all need to represent actual temperature of whatever it’s sampling, other calibrations like iac’s and drive by wire need to be done. Don’t forget on standalone’s ignition inputs & outputs need to be setup for whatever system you are using, like tooth wheel counts and high or low output for coil/coils.

3. How I’ve always done it is once the above has been done I start with the ignition table, this takes a little experience but it’s not black magic, keep in mind that more efficient cylinder heads usually need less timing, example years back I use to tune the e36 m3 cars and I believe the engine was a m52 straight 6, those engines barely needed any timing to make max power NA, like 22-23 degrees, I’ve done LS motors that max at 26-28 these are pump gas cars, anyways setup a starter table (I’ll provide more info later) then move to VE (for sd) turn off all adders like PE (power enrichment) and AE (acceleration enrichment), for the 7730 I would log actual afr vs commanded afr, simple math just correct the difference, once the car feels and drives good like that I work on AE from there it’s PE, go back when cold and to cold start, once it starts and drives good it’s time for some dyno tuning.

This is from some tuning classes years ago from Fast efi, it’s a good place to start when trying your hand at setting up ignition tables.

 

OE’s ignition criteria is different from say tuners, performance race cars usually don’t have emissions equipment.

Different names have been used but when it comes to timing for power we go by mbt (mean best torque) or the like, basically you want the max pressure generated from the combustion event to happen in a crank angle that gives the most power, my favorite example is the bicycle, anyone that’s ever ridden one knows that there is a best spot to get the most speed from where you apply the most force on the crank, to soon and you smack your foot on the pedal (tdc), to late and you just waste energy. For a gas engine somewhere in the 12-15 degrees is best.

But you don’t always want or need max power, example I had a customer with a big inch high hp engine that he had some of the best known tuning shops here in NY tune it for him, he blew two motors and believe me we are not talking cheap, this was/is a Sonny’s big block like 50k just for the engine. When I looked at the tune file yeah the wide open tune was perfect but that shouldn’t have been hard because Sonny’s provided a dyno sheet, of course that was with there carb and dyno but you have a good place to start, anyways this thing was so hard to drive on the street because it made so much torque, by backing out the timing the torque and obviously power dropped making it more docile for street driving, the top of the map was left alone.

So my point is timing can be used as a tool but too little time and you sink a ton of heat into the exhaust, one of the ways the oe’s bring that cat up to temp faster.

 

This one is also helps for those starting out.


One thing though about idle and afr’s, some cams/engines won’t idle with say 14.7, shoot I’ve have engine that wouldn’t idle unless it as as rich as 12, this was a drag car though but my point is don’t go by the number go by what works.

 

I've been tuning on my car since 1998, and it's been a bit of a meandering process because of all the things that pop up, various changes to the engine, things that I learn along the way that I didn't know before, etc... but on the whole, if I had to boil it down to a process where, if i started today knowing everything I know now...

I guess the way I did it was to get the BLM's inline by tuning the VE tables first. Then took a first cut at the PE.

After that, I simply leveraged a lot of stuff from other factory bins of similar configuration.

For example, on the accelerator enrichment (AE) knowing my Miniram was so similar to the 4th LT1's and then finding out that the 92-93 speed density LT1's had the same AE table types and formats, I experimented by copying and pasting the values directly. To my surprise, it brought the AE in line by probably 90%. Without a doubt, it would have taken me years to iterate my way to that result. Of course, I spent a lot of time after that getting that last 10% to perfection (given the Miniram's sensitivity on AE), but I tend to obsess over things like that.

I then grabbed the spark timing map from a 93 Corvette and used that as a starting point. Then over time, finding out that the Minirams really like part throttle spark timing, added quite a bit more in the low-mid map region. The spark timing did have a minor effect on BLMs, so I then went back and adjusted.

And then these other changes affected the PE a bit, so then I went back and tweaked the PE.

Having access to the results of GM's R&D on the LT1 tuning was a HUGE benefit and time saver. As I mentioned before, that was a key thing that allowed me to keep the Miniram, otherwise I would have considered it too difficult to get right and probably taken it off. It's like you alluded to, you don't want to start from scratch where you don't have to.

 

Yeah, don't be afraid of ignition timing.

Matter of fact, if you look at the 90-92 L98 Corvettes, they run a ton of spark timing at low to mid map. I had originally thought my spark map was aggressive with the LT1 tables, but then when I saw the L98, I merged the two together... I essentially run L98 timing from 20-60 kPa, and then LT1 timing from 70-100 kPa (the LT1s were far more aggressive at higher map than the L98).

The Miniram start bin I sent over runs the LT1 spark map as-is. But as you get further along, and with your cam (and after seeing how your knock counts are) I would suggest also increasing the spark map as you'll get much better seat-of-the-pants feel with the throttle during part-throttle driving.

 

As for TCC ideally you want it to come on as soon as possible when your goal is fuel savings, but gearing, engine size, torque output and cam all play a role, if I remember correctly $8d was like 40 or 45 mph in third, this is really not a problem if you’re on a freeway and a stock tpi with relatively good torque at 1500-2000 rpm, add a huge cam and gears now your torque curve has shifted, cruising rpm has changed and she lugs, you can try to add timing to see if it bumps the torque up but you just have to move the lockup rpm higher say 50 or 55, some combos just won’t make enough torque down low.

I should also mention that the above tuning strategy is for open loop, I try to keep any adder and multipliers off. The reason for closed loop is for emission purposes, the cats need to be at temp as soon as possible and the fueling need to be at stoichiometric for the cats to do their job AND this is big there will always be an error from what’s happening in your engine to what the ecu is see, this is why it swings rich lean around stoich with short term and long term trims, the short and long help for things like sensor and cat degradation and the swing rich/lean helps for things like temp and climate change among other things.

 

I'm still working on the VE tables for the time being going to get into ignition timing soon.

I know for these data logs I need to disable the features that add additional fuel or timing so I can get an accurate idea of what the car is going. But I realize I think I'm missing a couple possibly important points.

- I currently set the required throttle for PE up to 95% to disable that, which seems to be working, or should I up it to 99% to be sure?

Otherwise, do I need to disable and if so, how would I disable:
- Deceleration enleanment
- DFCO
- Highway Fueling
- AE (Acceleration enrichment)
- SA (Spark Advance)

 

I don't know that I would disable the Decel Enlean or DFCO...

Highway fueling I think comes disabled from the factory. Otherwise, in the scalars, find the minimum speed for highway fueling and set it to like 200 mph or something.

Don't disable the AE. Instead, find the switch/flag for Reset Integrator when AE in progress and enable it. This will keep the ECM from considering AE fuel when adjusting the INT/BLM.

SA = Spark Advance. Don't disable that either.

 

So, I think I have my BLMs and fueling pretty good, at least as a good starting point. I even drove the car 25 miles to work yesterday, and it seemed to go smoothly.

I'm ready to start ignition timing. Is there a way I can use the history tables for ignition timing similarly to the way I did for the BLM tuning? It made things so much faster and easier!

I'm Seeing there is a Knock Retard Count. That just shows a zero each time, but you can count occurrences. I'm surprised though, because my dash on the laptop in the car only stated one Knock Count, why are these values different?

There is also Spark Advance vs MAP, and Spark Advance vs TPS. Would on of those work better? What value am I trying to maximize or minimize, or converge on? I have done a good amount of reading, and I do not want all out aggression, as this is a street driven car also, not just a race car, and frankly, I don't want any risk I am going to blow up my brand new engine... any time soon or in the future...

 

RE post #81

SA tuning is a bit complex to explain.

On $8D you have SA managed in idle mode and SA managed in normal mode.

SA main table is the primary table but other tables will add or remove to it.

You also have the infamous “cold SA” feature to add to the complexity.

In WOT you have a PE SA adder

In open loop, there is also some SA stuff going on.

… and so on.

The knock retard feature is a main pain in the a**. It was flawed from OE which can trigger a lot of false incident pulling up to 8*. It was not designed for performance engine with headers and stuff. Also the low octane knock retard routine has to be disabled.

On certain tune the KR won’t be activated until engine is quite warm. Could experienced knocking if engine not warm enough.

Knock count is not accurate to detect knock. You need to look at knock retard. Every time knock retard goes up it’s an incident, even if knock count doesn’t go up.

At WOT you definitely need a chassis dyno to tune SA.

Commanded SA and SA at crank pulley timing mark can be different. The issue is well explained on TGO.

Ultimately, SA can only be tuned properly with a chassis dyno at different engine load.

I could go on forever, but I have no more drive to explain all this stuff, as a volunteer, on these forums. The info is out there, you have to find it.

If you don’t want to blow up your new engine, like you say, why would you rely on bits and pieces of information that you find on these forums? Unless you can secure a solid understanding of how it all interacts together first.

Again, I suggest you consult with @Tuned Performance. He would certainly get you started in the right direction. Worth the investment.

Peace

 

Personally what I would do for the simplest approach (given your short runner intake) is start with the 4th gen LT1 spark tables and disable the PE spark adder. Then monitor knock counts and knock retard while easing into the throttle as well as listening for audible pinging.

Then just kind of work your way from there.

Like SbFormula said, absent a dyno tune it won't be optimized.

 

Regarding the post saying just to pay someone to do it, I have considered it, but when possible I prefer to learn and understand what is being done to my car. I've found once ypu educate yourself, most things aren't that hard to handle... I have a couple members I know I can go to if I throw in the towel, but if people are willing to help out and educate me, I'd like to learn and do as much myself as I can.

If going in for a dyno tune is the right way to do it, I'll definitly have that done at some point...

Any good places in the Chicago IL area to have it done???

@ULTM8Z im actually using your SA tables as a starting point. I'm using the knock retard history histogram as an indication of where I need to pull timing, or I can add a bit more timing. My plan is to take the VE tuning spread sheet and modify it to work in a similar way for SA tuning with the KR histogram.

I've read about methods using throttle % and MAP values, but I don't see a closed loop tuning logic that makes sense to me...

I've also considered looking for factory bin data from an LT4 engine which has the short runner intake and a bit bigger cam, plus I believe aluminum heads, but the bin is a different format, right? Is there a way to convert it to our format for $8D?

 

Actually the timing map you have from me is from an LT1 Vette.

What I ended up on mine was essentially LT1 Vette from about 50 kPa and up and L98 Vette from about 50 kPa and below. The L98 is actually more aggressive in the lower map region, which I found the Miniram really likes.

 

So, when you guys talk about needing a dyno tune to be perfect, is that meaning have the dyno place do the tuning, because I'm not finding any OBD1 dyno tuning places near me... Or do I just go do a dyno run, then bring the data log home and analyze something? Realistically why can't I just find a long stretch of road, shift my auto down into second, go slowly till it shifts to second, then floor it to redline while logging?

When is it considered safe enough to try full throttle pulls? I have still never gone WOT...

On the timing topic, you mention "monitor knock counts and knock retard". I understand people like to have a second person looking at the computer while driving, but I would really like to figure out a way to use that histogram, then tune in iterations like we did with the VE. Would the goal in that table I shared before to have zero values everywhere, or just values below some minimum threshold? It is also counting instances of Knock Retard, so depending on the length of the data log, you will have higher or lower values, my though was to divide all values by some percentage of the largest value, so you end up with a scaled value. Thoughts?

 

I do want to say this is a long process, that takes a lot of repetition, learning, research, and questions...

I am SO THANKFULL for all that have answered questions and provided tips.

I'm getting pretty tired of this though, and I'm seriously weighing the effort vs just paying someone to finish this tune. I feel like I'm getting close, but then all these other topics keep popping up. I really do get a big sense of satisfaction, in doing this myself, and like that I understand what is happening and why, but frankly, I don't have a ton of time to put into this as the weather improves and I'm spending more time with family activities.

I guess this is a warning to those reading this in the future, that this is a long process.

It's also a question, based on what we've discussed so far, am I getting anywhere close to completing this tune, and enjoying my new engine, or is there still a long way to go???

 

So for the time being I'm sticking to it...

I just did another long log. I happened to find another thread where they were using the averaged Knock retard like I am, but they were using the running average and not the running count, like I was. I though any instance of knock retard was bad, so counting those was beneficial in tuning timing, but in my reading the running maximum was showing where the ignition was being retarded based on knock picked up. I just re-ran my log through TP, using the running maximum, and while a lot of cells populated, but not all, they all still showed zero, not a value....

Does this mean all along I have actually not been having any knock retard actually happening? If this is the case, what are these counts I'm picking up? Another piece of into, is that tonight during the log I started the car up and as it came up to temp my knock counts on my TP dash, went up to 4. Then stayed at 4 the entire time I was driving and logging... So again, am I actually getting no knock or knock retard? Or at least not enough to pull timing for? I already pulled ~2 degrees in the highest count areas of the chart from my previous logs, on two occasions, so some areas probably have had 4 deg of timing removed. Should I go back to the timing charts from before I started this, and start working the other way, increasing all areas 2 deg at a time until I start seeing knock retard, then pull 2 deg from that SA value?


All Zeros when running Knock Retard, Running Maximum

 

I believe the ECM forces knock counts on start up to ensure the knock sensor is working, so that should be normal.

Assuming the knock sensor is installed properly and working, then yeah, you're evidently not getting any knock retard kicking in. Suggests you could potentially benefit from some additional timing.

While 0 knock retard is a notional goal, a few deg of retard every now and then isn't a problem. I've tuned mine such that I get occasional retard up to about 4 deg. Though I increased the knock retard attack rate for a bit of added protection so if pre-detonation is detected, the ECM will pull timing even faster than GM initially programmed. That's the beauty of EFI with spark timing control vs a carb... I can go super aggressive on the timing and count on the ECM to protect things. I've never ever heard audible pinging with this approach... I know what that sounds like since years ago I attempted to run 10.2:1 compression with a relatively small cam and could never get the knock under control without severely cutting back on the timing. I could hear audible pinging inside the car (which ultimately forced me to lower the compression).

Any rate... to answer your earlier question about dyno tuning and when things are good enough...

Ideally they'd tune while on the dyno so they can iterate and see the results. I ended up just tuning spark timing by seat of the pants and TP history data on knock retard... and for me it's good enough. And to be honest, with as much time I've put into it, I've gotten to the point that I can detect a performance change over just a couple of deg of timing one way or the other now... which tells me I'm extremely close to being optimized as it currently is. But also having leveraged 99% of what GM did on the L98 and LT1 Vettes, I know I'm in family with what has proven to work.

That said, where I knocked myself out looking for "perfection" was on the AE... you can see all the posts and threads I've made on the subject over the last few years... lol. Though it paid off in spades as the throttle response is to a level of sharpness I never thought I'd ever attain.

Another area you eventually may want to play around with on your setup is the target AFR during closed loop using a WB O2 gauge... and the way you do that is to change the O2 rich/lean thresholds (not the stoichiometric constant!!!). In GM"s "infinite wisdom", the factory code has the R/L thresholds going leaner with increased engine load for some reason... going from ~630mV at low load down to 520mV at high load. That always seem a$$ backwards to me.

With my WB, I've been able to target about 13.5:1 under non-PE loads.... which also makes the transition from non-PE to PE feel a little more seamless (as opposed to going from 14.7 commanded down to 12.5 in more of a step function). That's also a way I'm able to run such an aggressive spark map is because I run a little on the richer side of stoich under non-PE loading conditions.

 

Did another nice long data log ride today, local and highway, beautiful warm spring day. Even got in a pseudo 0-60 run, did not go full throttle though. 5.3 sec is a start without full tuning and full throttle.

I did check the log after and found I got up to 5 knock retard counts during start up, which if I understand correctly are forced by the ECU increasing timing until it detects knock, to verify the knock sensor is working, but then for the rest of the log, my knock retard counts never changed again. I checked the knock retard history table again, and it's just a lot of Zeros...

I did as suggested and combined the LT1 Vette table for higher Loads, and the L98 Vette table for lower loads for my SA tables. I increased small region slightly as I read it improves low throttle cruising and upped the rest of the table by 2 deg as a start to see if I started getting any knock retard, but still none. Do I keep adding 2 deg at a time until I start seeing KR? Are there specific areas where you would add more or less? Some of these numbers seem pretty high already... That said at higher throttle and engine speeds the engine sounds pretty happy, where it struggles is idle and cruise... So, I need to improve that somehow...


SA Tables From Last Data Log

 

At first glance, I think you might be getting a bit high at higher MAPs... I'd probably be down around 34. I guess you can try to lower it and see if you lose power. Maybe it likes that much timing.

But I'd probably pull the spark plugs though and look for any kind of salt and pepper appearance, which would indicate knock. If you're not registering any knock counts and you're not hearing any pinging, that's probably a good sign.

For reference, here's my spark map...

The sluggishness may be the result of AE fueling. Are you using the Miniram start bin AE?

 

I went through and adjusted my AE fueling to match yours, I also tweaked my ignition tables as you suggested to more closely match yours. I don't feel like it made a significant difference on the way into work today... Maybe a small amount. I ran the history for knock retard and still got all zeros. I will say this time I started the Log before starting the car so I could see what it did for the function test right after startup. Looks like it initiates the test about 2 seconds after startup. Green below indicates startup, red are rows with knock retard. Does this look to be correct for what you would expect from a properly working ECU and knock sensor? It's interesting that there is a forced knock column that says no knocks or Test in Process, so I guess that verifies that this knock is a result of the ECU running the test...



I came to an unfortunate realization today... I'm wondering if I just have unrealistic expectations of the drivability of this cam... I had a cam spec in mind based on my research, but since I liked the offerings from Smeding Performance where I got my short block, when they offered one a bit bigger and one a bit smaller, I of course went with the bigger one. I'm thinking I should have gone with the smaller one... The duration on this thing is 231/236 @0.050". (The smaller Smeding one was 220/224. I was looking for 224/230 and the lift was down from my desired .510" at factory rocker ratio at .495". Giving me .544" with my 1.6 roller rockers) Looking at the most similar mainstream one I can find, the Comp Cams 8-432-8 XR282HR-10, granted that one has a 110 deg lsa, mine is advertised as 111 lsa, but that cam has an advertised operating range of 2200 to 5800 RPM... my cruising engine speed is 1400 to 2000 RPM. I'm going to have to tune the best I can for now, and maybe change it out later on, but I do not want to have to do a cam swap right now, I just want to drive the car, and try to get to an autox event before the season ends...

Am I in search of the unachievable? How smooth and drivable should I be able to get this engine with enough tuning?

 

I don't know... personally that cam would be way too much for me. You probably are in fact giving up some lower end performance given you're also running a shorter runner HSR manifold.

I like to err on the side of caution with cams... I only wanted to do mine once, so I was prepared to sacrifice some upper end power in exchange with a mild-mannered setup. As a result, I'm running a cam with 215@.050 on a 114 LSA in my 383. The car is 100% a street driver with occasional spirited driving and I wanted a factory-like idle. The car has plenty of power for me above 5000 rpm (though I'm not going up that high very often). But it has an ungodly amount of torque in the low-mid range, which is what I want.

You might want to experiment with having the AE decay out a little faster by playing with the following...

Table - AE Delta MAP PW Decay Factor vs Coolant Temp => I'm into the ~60% decay rates on this.

Scalar - AE-TPS, Done if DRP Counter (location 0x530) => I have mine reduced to 8 DRP's (Distributor Reference Pulses).

Having the AE fueling decay out a little faster seemed to make the throttle response significantly more crisp. Just get enough AE to deal with the throttle transition and then get back to regular fueling ASAP.

You can also start tailoring AE fueling by RPM using the table AE Delta TPS Filter Coefficient vs RPM. Lower numbers = Richer. Higher numbers = Leaner. Maybe at the lower rpms with less volumetric efficiency it wants a little less fuel.

I find that AE fueling is crucial in how the engine follows through after the throttle transition...

 

Yea, I should have stuck to my plans of a smaller cam. It's hard to resist the sirens song of bigger and more overall hp is better, when sometimes its not... I guess at some point in the future a cam swap is still less work than building up and changing out a whole engine... I think I'll be better served one day by a cam with 224/230, or maybe even 218/224, or something like that.

For now I need to get the engine tuned the best I can so I can drive it more regularly, and try to get to an autox event!

I've decided the best way to do this is to entrust someone experienced in tuning to take over... I hate to be throwing in the towel, but it's just requires more time than I can afford right now...

I'll still try to share some periodic updates here when I can.

A BIG THANKS to everyone that has contributed so far! Hopefully there is still some good info and answers here for other new tuners struggling through the same kind of situation as I have in the future.

 

You won't find many shop that do dyno tuning on these old system. You might want to rent the dyno, that's what I did. There was a shop that offer this option near me. The shop owner operated the computer dyno part of it and I operated the car + tuning on the go with Moates Ostrich 2.0 and AFR gauge. It's not about perfect, nothing is perfect. It's about having the right timing at WOT for maximum HP/Safety ratio. Tuning SA for cruise can be done, but be ready to spend hours on the dyno.

Not surprising. No support for these old systems... except good Samaritans on TGO

Could, but boy that would be time consuming and inefficient. That's why you need an emulator to be able to modify the tune on the go. Also having your laptop with you. Dyno rental is by the hour.

And what would you accomplish? How do you know the HP output. About risk on public roads, etc...

That's when experience comes in. You need to start rich and with less SA, do a half pull and see what the AFR is, then a 3/4 pull and see, etc. With a dyno, you can control the engine load better and not have to worry about speed and traffic. You can also tune on the go.

 

Took me 16 years and thousands of hours and I am still learning. That's the issue. Everyone has to go through it. Now, I am getting older and I am not as motivated to repeat, repeat and repeat again on these forums what I have learn with thousands of hours of reading, data logging and tuning. Look at my profile, I barely asked any questions on TGO. Also, some of the pioneers are now gone from TGO and you are left with the second or even third generation of TGO's "tuners". Knowledge is eroding.

I have to chuckle at this one. I have repeated this on and on and on and on... But no one listens. Then they turn around and "warn" others lol

 

I have seen the $8D adding knock count on Start-up even with KR disabled and no actual knock sensor hooked. Don't worry about it. Look at knock retard only.

 

When tuning, you need to temporarily disable knock test

 

Just as a side note. Tuning SA intuitively based on what others have done is not the best. For instance, the common wisdom for small block chevrolet is max 34-36* at WOT. That's measured on an engine dyno with precise tools.

In reality, with this antiquated system, the commanded SA and real SA the engine experiment can have discrepancies. One way to find out is to actually visually test that SA at timing mark vs what the ECM is commanding. Here's a good thread on it: https://www.thirdgen.org/forums/diy-...ncy-table.html

Take the time to read it. By the end, there is up to date important information. Thanks to late @RBob for all is knowledge. He is missed on TGO.

Other thing is, depending on your engine and gas quality, SA can vary at WOT. Example, in my case, I can only get E10 with 91. Plus, the quality isn't the greatest. I was experiencing bad knocking with only 24ish* at WOT IIRC. Came to find out, SA latency was incorrect and real SA was more 28-30* at WOT, a +6* from commanded. Also, bad gasoline quality was a factor, which is known by tuners around my area. In the end, I had to tune SA latency and add boostane to gas. Once on dyno, from 28* to 30* at WOT we gained 7WHP. From 30* to 32* we only gained 2WHP. We dialled it down to 30*.

That's what the engine wanted at the time in those circumstances.

 

Another side note...

On a perfectly stock LB9 '89 IROC TPI M5, I ran a bunch of SA testings. I concluded that KR was a combination of false and real events. That's how accurate those systems are. I had to tune based on SA average, not immediate SA. I also detuned the Knock attack/recovery rate to help smooth things out.

Results summary:
(effective SA means SA-KR)

Before tuning with OEM tune
Best 0-60mph, 7.0s
Best 1/4 mile, 15.2s @ 90.0mph
AFR at WOT: high 9s to low 10s, (O2 voltage 924-963mv)
Ave effective SA at WOT: 28.9* (2nd), 28.4* (3rd)
Ave KR at WOT: -2.9* (2nd), -3.5*(3rd)

After tuning
Best 0-60mph, 6.7s
Best 1/4 mile, 15.0s @ 91.5mph
AFR at WOT 12.3-12.8, (O2 voltage 850-890mv)
Ave effective SA at WOT: 26.0* (2nd), 25.2* (3rd)
Ave KR at WOT: -0.6* (2nd), -1.4* (3rd)

That was on none ethanol 91. Government change regulations later and we now can only get E10 91. That threw off the tune and WOT AFR had to be readjusted as we were running lean. That's why you have to keep an eye on gas.

Again, I could only get 25-26* at WOT, not 32-34*. However, car performed as advertised by GM

If you are interested: https://www.thirdgen.org/forums/diy-...89-camaro.html