Hi...lets talk/see spark advance.....

I have looked at two PROM's from two of the most known programmers.
Both proms are made for a -89 MAF car with similar setup, heads(no1 AFR, no2 ported vette heads), cam and intake, and as you can see the are NOT like specially at high loads.....

This is as I can see a good reason to do your own proms, two of the most well known in the buisness and the are so diffrent makes you wonder who makes the best ones.

Moderators: if you dont see this as a DIY prom post, delete it.....

 

Interesting tables. As it is the upper table looks like a stick car while the lower table looks to be for an automatic. Would you happen to know how the TCC/ShiftLight bit is set on each bin?

RBob.

 

This is a real interesting post. I'd like to hear from some of the DIY guru's about their thoughts on the differences in the two programs. It's also good that you didn't reveal the names of the tuners who did these programs to keep the discussion on the programs rather than the tuners.

Do you know if these were dyno tuned cars or just a call the tuner and give them your specs type of deal?

 

There are some varing thoughts about timing. The one I've gone with is min amount of timing for a given result. Others go for running ever degree possible. Using those two differences and required fueling changes generates two very different looking maps. Not to mention as Bob said, an auto vs manual.

I've played with cruise timing of between 26d and 46d on my own car, and I now know what works best. I typically run the 26d at 70 mph type, whereas other good chip guys, IMO, run 38+ and they're happy with their results too.

But, I wouldn't say 26d timing is the ultimate setting, for everyone.

 

Ok...I looking forward to some coments..........

- Both are made for an automatic...
- Both are custom order PROMS (big $$$)
- The fueling is very similar, NO changes in MAF scalar tables same as stock APYU.....
- Some minor changes are made in PE vs rpm........

In the upper one the max knock retard was set to 4 deg. in the lower one stock APYU.....


For the discussion about timing I run about 26-28 max timing (still tuning) in high load/rpm and the curve at high load is very flat through the whole rpm range......

 

I've seen some .bin files from chips that guys have spent over $500 on. And some were little different then one that you could buy at the local store. What got me into chip burning was spending 325 on a chip that was junk. And the alledged problem was that my cam at 224 at 050 was just too large. Hahaha

It can be surprising how well a engine runs will, quote un quote retarded timing.

Generally below the stall speed of the converter you don't need much timing, and then hopefully the peak torque and stall speed are close, and from there to max HP shouldn't be too much of a timing change. Again, generally doesn't mean it's universally true.

 

I'll tell u what it is :-)

Go dig up vette bins from 86-91 and compare your timing tables..

Thats what i got for my formula spending $$$ and wasting my time :-( Ran pretty pathetic too.. Then i started doing it myself, and found basically what grumpy said, if it does the same with less , why go farther than u have too

Later
Jeremy

 

Wich one, no1 or no2?

What is the vette bin's name?


How can two diffrent tuners go for so big diffrence when it comes to timing at idle and WOT?

Ps. I also spended alot of $$ on a custom chip a few years ago(-99) before I made my own.....


/N.

 

If you want to post the bins somewhere, I'd take a look, to see if there is something just not strange with one.

 

Grumpy: that ok, you dont have to, I just wanted to show some stuff I've run in to.........

I know alot of people here in sweden who had bought expensive PROMS and their cars runs very ill. Doing youre own PROMS is very rare here (for TPI cars....) I dont know any speedshop/dyno/engine builder who has the knowledge of recal. 165/730 ECM......

another one:

I having trouble with my idle surging when in P/N but its fine in D.

If I look at the IAC its within 5 steps when in D but in P/N its within 15 steps. I guess this is why my idle is not stable.

Why is it "hunting" idle in P/N and not in D?

I'm out of ideas..........

/N.

 

gta324

Are either of the .bins running any PE Spark advance?

If so post the tables.

 

Let me se............. * I just love GMEDIT* ............

No PE spark advance.

 

Is that the total value?
Or is it wondering 5 steps but meaning say 20-25?.

Sounds a bit high.
Too lean too rich too retarded, or too advanced can do that. Is it closed loop?, if so what are the BLs?

 

Grumpy:

more like 15-20 but within 5 steps, yes ( and 15 in P/N. )

its in closed loop around 800 rpm. BLM is at 126 it idles better when in open loop.

Idle timing have been tested between 16-24 degrees ........

But I have some serious trouble know 15 deg .knock retard with stock ignition curve at 5200 rpm, no PE added....... Will have to check my lifters........