At what point do you think is "too much duration?" for the ECM to deal with / be tuneable.

I was thinking of having the following custom cam ground.. But wanted to ask opinions first.. Infact, I'll list my entire (new) setup:

Hydraulic ROLLER Cam: 230/236 (@ .050), .540/.540 lift, 112lsa, 110 intake center.

Forged turbo pistons with -21.1cc troufs (8.66:1 c/r)

TrickFlow 23 degree aluminum heads 64cc chambers.

Vortech S-trim blower

Holley contender (1205 intake ports) singleplane manifold converted to EFI, with vortec 80mm throttle body.

50-55lbs injectors, high impedance.

'730 ECM running $60

-- Joe

 

Using the 60 means anything you can taylor the code to allow for.
How about a special *mode* for idle. Heavy MAP filering, and fixed timing for say <800 RPM, less then 1% TPS.

Sky's the limit when you have your own code, and imagination.

 

I see your point..

-- Joe

 

Curious to see how it all works out. Comp Cam's Tech line had suggested a cam with those specs...or close to it for my 383 stroker. Now if only if i could get the wiring sorted out so i can convert to a 730.

 

I had to flatten out the timing and fuel map in the 2-3 cells that the idle jumped around in when at idle. Worked well for me. The cam in my TBI V6 is actually listed as not for computer controlled engines.

Teeleton

 

My cam is 242/250*_.560"_ 114lsa. It's well within the limits of the ecm. Then again, it's on a 406 that pulls 20" of vacuum at idle. I don't think there is a limit to what the ecm can handle. IMO, once you go so big, open loop is better...

 

Agreed, but your not running a 2-bar map. My concern was the granularity (is that a word?) of the 2-bar map.
Suttle/dramatic changes don't seem to affect map voltage much.


-- Joe

 

Maybe the tables need some work.
With source code you can have 5 K/Pa steps, at 200 rpm intervals.

Just in rought numbers, you have 255 steps for any MAP. So in 2 bar mode, you have 128 per atmos.. With 10 K/Pa steps or 13 counts per increment of code. Take that same 128, and then use 20 steps, and you still have 6 increments per increment of code. So your still tuning in 1 K/Pa steps. How close do you want to be?. With reversion, self EGR'ing, cross feeding, etc., etc., how much granularity do you need?. If you want a chuckle look at say a GenVI DFI.

With Source code your limited by your imagination.

 

I've had some weird tuning issues with my car that I wasnt really sure what they were. some odd intermitant hesitations, bucking, etc.. Thought it was tuning related, but I'm starting to think it was mechanical.

Seems, NOTHING survived my motor. Nothing.

When #4 and #3 detonated, apparently the piston cocked sideways and mashed the wall. We had to bore the cyl out 4.040 this morning (Coulda went 4.035 or so but..).

Gonna run a 383 piston with a 5.850" rod. . Only damn thing I could find in 040 with enough dish and thick deck to run the blower.. (JE/SRP)

The only good thing is the piston is do damn tall, we won't have to deck the block much.. Height will be around 9.015"

-- Joe

-- Joe

 

What you call granularity (I think that is a word), I call sensitivity, others may call it resolution. Whatever you call it, the end result is that by upgrading from a 1 bar to a 2 bar MAP sensor, the measured volts per kPa is cut in half and at 7 lbs. of boost, you never use 1/4 of the sensor.

 

True, but i'm running 12psi.

-- Joe