Hi!

I think I have a decent base tune. I have got it to idle open loop with a roll between 50 or so RPM (725-750rpm).

Attached is a data log. Mostly cruise with a couple short runs near 70% throttle. The first one was up hill and the second was on a straight away.

I was hoping for some for advice on fine tuning the SA, PE, and AE.

Here are some details...

• Cam: .465" / .488" flat tappet
• Pre-86 Iron Heads
• 90lb injectors - edit
  
• 15 PSI
• No VAFPR
• 12 degree base timing

 

You'll need to confirm whether 80# injectors at 15psi will be enough to feed top end with an 80-85% Duty Cycle. I'm betting not, which is why you'll ultimately need to use a VAFPR. Are the TBIs // plumbed?

 

Totally plan to go parallel in the future.

15psi with the 80lb injectors at 9.5 compression is at about the upper end of what I can do before I must go VAFPR.

I did finally get to look at (and copy) the SA table I had a professional tuner make for another EFI car I had many years ago. That car had a .450" plus cam with the same heads. Loaded it up and did some VE learns this morning.

So what does that mean? Wow- I am glad I found that old file. I am really, really happy now with the performance out of the engine!

 

Which version of XDF file are using???? V31.XDF??

Took a look at your Main SA table - It does not look right to me. You are getting 18 deg at WOT (100 kPA) at 2800 RPM - engine must feel very slow. CI heads should be able to handle 30 to 32 deg at the same point. So something is off in your setup.

Initial SA is set 11.60 deg - as long as this is correct with EST plug open there is not much that can be said about your bin file.

In the Datalog
Very conservative timing - which corresponds to BIN file.
Idle MAP values for your setup around 60 kPa - what are duration @ 0.050 and LSA values for your camshaft?

//RF

 

I would put money on that cam being an early 70s grind cam.

290/300 @ .006, 224/234 @ .050, .465/.488" lift, 107* ICL and 112* LSA

Not trying to be mean or rude, but nothing in this build indicates that it will build good power.

 

Went back through things...

SA table is better now.

 

Going through my logs, lists of parts, etc... whoops.


I'll admit it- I screwed up with the BPC values relative to the injectors.

I have TJ11 Injectors. They are 90lb injectors and not 80lb. Confirmed per manufacturer.


I've gone back and reduced all values in these three tables to the new injector flow:

AE - MAP PW
AE - TPS PW
PRP - Gain vs O2 Error

 

Few years back I played with a similar setup - 350 equipped with Howard's Cam with the following specs:
Duration at 0.050" lift 225/235deg
Lift with 1.5:1 0.465/0.488"
LSA angle 112 deg

I was not pleased with this cam selection for EFI application, but we made it run good enough. Idle was fair to OK and overall power was OK, but the power band was somewhat narrow and higher in RPM range than I wanted. Engine really wanted to have 2.02/1.60 and better flowing heads vs. what the guy had on his engine - early 70's performance heads used on LT1. We did what we could. We started with modified '90s LT1 SA profile - it mimics light springs for mechanical advance and provides around 29 deg at 2400RPM at 100kPa. This is what it looks like - bottom right corner 400RPM/100kPa should match your initial SA timing - makes for an easier start.

//RF

 

Thank you so much!

I have learned a lot over the last few months. So, I really appreciate the help.

I've gotten an idle I am happy with- not sure my frame of reference is that good- but seems okay to me.

I am working on the VE tables now through VE learns. RF Master- would you have a copy of what your VE tables looked like for that cam? I'd be curious as to what they looked like and what else you did in terms of adjustments.

Thank you in advance- I really appreciate all your time responding and helping out! This is very helpful to someone who is new at this and learning.

 

Remember that the EBL.bin has a pe adder adding timing. RF's table may have that zeroed out. Point is total timing may be more that you anticipate.

 

Yes, my PE adder table is zeroed. One of these days I'll have to play with this table and see how much performance difference can be gained...

//RF

 

Thanks guys!

I am going to experiment with zeroing out the PE adder and using the main table to handle the heavy lifting. I have looked through a lot of different BIN files and seems like that strategy is used frequently (I think I saw that 85 & 86 Vettes as an example don't have SA added during PE).

I still have my wideband yet to install... but happy so far with where things are going. Idle seems okay in drive... although it will idle kinda high (like around 1k rpm) after it has been run kinda hard and then placed into park. Not sure what is going on there. Doesn't happen all the time- but when it is around 195 degrees of coolant or so and fairly warm on the AIT.

I did notice that when I corrected the BPC values in the two tables that my VE values changed mainly on the low speed tables during the last four or so VE learns. I guess that is related to changing the way the ECM is driving the injectors now. By telling the ECM they were 80lb injectors, it seemed to skew things where there was less VE below 2600k rpm and more required above it. By correcting the BPC to reflect the injectors properly, I've noticed my VE table values have increased below 2600rpm and have also dropped a bit above that.

Interesting stuff.. again, learning a lot here!

 

I really do not recomeend Zero'ing the PE Adder table. It is there for a reason! The leaner mixtures of part-throttle, closed loop do not need as much timing as the richer mixtures and you can create a situation where your engine knocks at higher loads, non PE.

 

Oh- okay. That's good info! THANKS!

 

I'm going to wire in the TT-01 WB tomorrow. I spent some time today deciding how I was going to route it through the car.

So, we'll see how things go on the VE learns... hopefully I'll get the chance to do some tomorrow some time.