I am undergoing tuning my new project.
383 with 42#SVO, L92 heads, lS3 intake, and large cam.

I will be using autotap and LS1edit... because that is what I have...

Can someone point me in the direction of a excel spreadsheet to import my autotap logs into?

Thanks,
Rick

 

Sounds like a very nice project. I understand which tools are at your immediate disposal and that you would like to take advantage of them. I don't have a fast answer on LS1edit and Autotap for you but, I would like to point out some advantages of upgrading your pcm/operating system to a 99+up.

First and foremost, being able to avoid the limited capability of the backup VE table. The resolution of the backup table is halved, meaning you are going to have to interpolate-which is time consuming and not very precise. (Which I had to do with my 98 prior to converting it.)

Realtime tuning- keep the lights on so to speak, while you are in the whirlwind of getting idle tuning down pat, making small changes with the motor running cuts things to the chase real quick. Drivability, same same.

Custom Operating systems for N20 and Forced Induction can only be had with the upgrade as well.

Ok, I'm off the soap box. I wish you luck with your project and if I can be of any further assistance, let me know.

 

Thanks Doc for the reply and advice. I can actually upgrade to a 2000 PCM but was not sure if it would be worth the trouble for a NA Strip car. I have no plans for forced induction, at least not in the near future.

I have noticed what you mean about the "halved" secondary VE tables, but have no clue what you mean by "Interpolate" Could you explain.

At this time, I have my idle pretty decent when in closed loop, but I need to work on it in open loop and still have to tune every where else which is why I need the excel spread sheet so I can start logging and see where she is right now, and which way I need to go.

It has been several years since I tuned and and I am having to relearn a lot, and it seems a lot has changed since I was tuning in early 2000 - 2002.

Thanks again

 

Let me start by saying that all of what I am about to say is based on part theory, and part actual knowledge of what the manufacture has actually published in the technical manuals which is limited at best.

The theory part is based on what experience I have with GM propreitary software using aftermarket tools (EFI Live, HP Tuners, LS1 Edit) to yeild repeatble results.

That said, I will not say that my way is the only way or, the correct way.

The pcm knows what the displacement of the motor is so, the key to power and efficiency when you change the Volumetric Efficiency of the setup with go fast parts such as heads, cam, etc. is to accurately re-map the airflow calibrations.

LS1 pcms have two airflow measurement systems 1) The Mass Airflow Sensor (MAF) and the 2) Manifold Airpressure Sensor (MAP). In a stock configuration the pcm is blending measurements between the two below 4k rpms. The MAF is very accurate above 4k rpms but not so good at lower values due to reversion.

Enter the MAP, or Speed Density (VE table). Very accurate at all airflow levels.

Some folks completely ignore the MAP or VE table in lieu of just adjusting the IFR and or MAF table(s), different strokes for different folks- it's all basically a hack of a propreitary system to me so, whatever gets you results.

Now, onto your situation with the 98. If you choose to employ the method I have described by recalibrating both airflow measurement tables (MAF and MAP) you will need to isolate the base table (VE (MAP). Most folks do this by
setting the MAF diagnostic to fail prematurely.

GM never intended for you to do this and on the 97 Y and 98 Y & F bodies doing so will force the pcm to use the backup VE table which is almost halved in resolution. My theory is that the existance of this table was meant to be an insurance policy to allow you the consumer to not be stranded in the case of a real MAF failure.

With the lowered resolution you will not be able to make direct quantitative measurements with your data logging system. You will have "holes" in the data stream that you will need to employ a spreadsheet to interpolate or basically guess by averaging the surrounding data.

A brief analogy would be like this, I can send you to the store barefoot to get a six pack of beer or, I've got a brand new pair of the best NIKE running shoes you can make the same trip with. You be the judge.

Upgrading your pcm and software to a 01+up setup will allow you to avoid the lowered resolution of the dreaded backup VE table as GM discontinued the table in 01.

Once again, weather you decide to run sole SD or normal blended airflow measurements both have to be calibrated for smooth operation.

Hope this helps.

 

If I may add to the discussion, first, a quote from Wikipedia:
"A manifold absolute pressure sensor (MAP) is one of the sensors used in an internal combustion engine's electronic control system. Engines that use a MAP sensor are typically fuel injected. The manifold absolute pressure sensor provides instantaneous manifold pressure information to the engine's electronic control unit (ECU). This is necessary to calculate air density and determine the engine's air mass flow rate, which in turn is used to calculate the appropriate fuel flow. (See stoichiometry.)

An engine control system that uses manifold absolute pressure to calculate air mass uses the speed-density method. Engine speed (RPM) and air temperature are also necessary to complete the speed-density calculation. Not all fuel-injected engines use a MAP sensor to infer mass air flow; some use a MAF (mass air flow) sensor. Several makes use the MAP sensor in OBD II applications to test the EGR valve for functionality. Most notably General Motors uses this approach."

"In the mathematical subfield of numerical analysis, interpolation is a method of constructing new data points within the range of a discrete set of known data points.

In engineering and science one often has a number of data points, as obtained by sampling or experimentation, and tries to construct a function which closely fits those data points. This is called curve fitting or regression analysis. Interpolation is a specific case of curve fitting, in which the function must go exactly through the data points."
So, you would be estimating data points between known data points. Tuning your Volumetric Efficiency (VE) Table can be done; I would suggest a simple Google search to get started.
I suggest you are limited, if LS1Edit is anywhere close to LT1Edit (which I am stuck with) but it can be done. If you can find an LS1Edit user's forum, they can offer assistance.
BOL.

 

It may be time for a new software, but my biggest problem may be with the 98 PCM. But others have over come and so will I .... hopefully lol

 

We will see what we can do this weekend Richard.

 

Hell Yea!

Disregard the WOT popping I mentioned, (Plug wire/header) fixed...

 

I agree with Doc, upgrade to an '01 or '02 OS...

this requires some work re-pinning the PCM connectors, but it will save you time in the long run.

 

How did you get the L92 heads to work on a LS1 block? Is your block resleeved for bigger bore?

 

I think technically it is a 375.129" motor. Iron block with a 4.06" bore and stock 3.622" crank.[Wrong, see below.]

 

That would be the best thing, and we may do that in the future since he has access to a '00 pcm and my HP Tuners is licensed for '99 and '00. I just wish we had the 1 Bar Speed Density upgrade for the '00 pcm.
Where is all of that spare change we have laying around since our wives are both in nursing school.................

 

Resleeved LS6 block 4.10 bore

 

Ahaaa. The iron block idea got shelved.....

 

The only flies in the ointment with the 98 HPT swap are going to be the

A) The 98 VIN
B) Getting the fuel gage to work

EFI Live doesn't care about the VIN and you can swap the fuel segment as well.

 

We got it REAL damn close today using my HP Tuners to scan the narrow band O2s and then using that info to change the tune using Richard's LS1Edit. We were doing great untill the driver's front tire cam apart during the log session.

 

I told you that I didn't hit a dog.. but noooo you wouldn't believe me until we got out and looked

Not bad considering not having a front tire...lol

P.S. Thanks again Mike for the assistance, sorry for the scare though..