Blazin4x4

I have a 355 with 10:1, 670 cfm tbi, L-79 blueprint hydraulic cam (.447 lift, .222 dur) afterburn flowtech headers, camel hump heads, k and n, holley fuel pump, 3 inch single exhuast, holley projection manifold, with a pro prominator and the 7747 computer.


I am starting with the .amur bin but I can't get my rig( 88 k5) to run long enough to log data. I cut the injector bias in half to compensate for the larger injectors... they are 80 something pph, stock are about 2 times less(anybody know the stock injector size). I also moved up(leaning out right?) some of the "Squares" on the VE fl1 map. (what does the second VE map do)

Does this sound right?

I need some serious advice... I'm about lost.

Thanks in advance.

michal_larson

ok man first of all, let me congradulate you on your cam, heads and ecu man its awsome that 60's stuff aint it

RednGold86Z

iTrader: (1)

Injector Bias is not the thing to change for larger injectors. That is only a very very small part of the fuel pulse width calculation. That is mainly a compensation to the speed of opening and closing of the injector, although small, can make a slight difference to the calculation of air fuel ratio changes.

Base Pulse width on 7747 is what I think you need to change (others need to step in now, my 7747 experience is a few years old, and only 1 car on it).

michal_larson

stock 350 injectors are #62 for 350's, some of the 80 lbs injector fuel regulators had higher pressure springs in them around 18 PSI, you would want to use a 305 or a 350 spring they are orange with 8 turns, the high pressure springs are shorter and stouter "7 turns" .personally this is what id do before messing with that (and ive done it to) is stick with the "AMUR) bin and use the "VE as of % (FL1)" and (VE as of % (FL2) from "ANTZ8364" bin as thats the bin for those injectors, you will notice that the fuel map is flatter near where you engine vacuum would be, might be easier to tune. moving the VE% in the fuel maps means more gas. the second VE% fuel map is just a global ajustment at a given RPM over the entire swing of your map sensor, in other words, lowering VE% in table 2 @ 3200 rpms would lean the engine @ 3200 across the map range. c? as for WOT air/fuel thats ajusted with PE AFR. man this is fun. running flat timing across 400, 600, and 800 rpms around 25 degrees across the spark map stailized my idle. man i was just thinkin, my chip would run in your car lol. as far as your injector bias, id stick with 274 Usec as that is what the bin for those injectors is. here is what id change......BPW Constant
Cylinder volume and injector flow rate are combined in this calibration value. A typical value for a 5.7 liter V8 is 135.

Cylinder volume is 5.7/8 or 0.7125L

Injector flow rate is 7.48 grams/sec, (61.22#/hr/injector)

Using the formula BPW = 1461.5 x (cyl vol / inj flow rate )

= 1461.5 x (0.7125/ 7.71 )

= 135

This constant should be changed if injector size or cylinder volume is changed.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++


your formula should look like this

=======================================================
Cylinder volume is 5.7/8 or 0.7125L

Injector flow rate is 10.07 grams/sec, (80#/hr flow rate)

= 1461.5 x (0.7125/ 10.07)

BPW (BPW constant for EGR off) = 103

=======================================================

thats what id change first before injector bias

michal_larson

man, im kinda proud of myself for that.

Blazin4x4

wow... I was WAY off... sorry for the late response I don't have internet right now... I'll give it a shot and see if that helps. I know you guys frown on .bin begging but I am way lost and my rig has had a new motor for a year and hasn't moved under its own power... mostly because of money and parts but the tuning is a lot more complex then I expected.

Thanks

Fast355

iTrader: (2)

Check out the thread in the TBI board, it is titled Come in for a free tune.

Check your PM.