7427 upgrade tuning help understanding

[Fast355]

Attached are more spreadsheet screen shots from the same combined data logs previously posted.

Injector Duty Cycle should increase with engine load / engine rpm.

BLM's and WBO2 data are not aligned. Closed Loop WBO2 tuning will have better overall performance!

For a daily driver 16197427, I like tuning with stock injectors, stock spring, with stock injector parameters. Perhaps, using higher flowing 16197427 7.4 liter injectors, stock spring, with 7.4 liter injector parameters is an option to think about?

Spark Advance is challenging, perhaps an experiment with minimum temperature for Knock Retard set to 151 Celsius will provide valuable data?

dave w

Anything with a 7.4 and the 7427 used a 46 lb/hr injector @ 28 psi. Barely enough fuel to support a stock 5.7 Vortec much less anything making any power at all.

I use 14.1 stoich on our E10 here. The fuel trims always seem to fall into line more easily as do the WOT air/fuel. 12:1 around peak torque and lean out to about 12.6:1 at higher rpm.

[typhoonss92]

Thanks for all the info, guess there is no spring for the 20-26 range, there used to be a gold one that would do 16-26 from what I read but have not seen one. So I guess my options are the big block injector that is 80-85# with a stock spring at about 15-16psi from the excel spread sheets calculations or get an external vfpr. I have the blockoff for the fpr and the special adaptors for the tbi so I can use 6-an fittings. If I go the route of external I have heard multiple different setups, keep your fpr but add the external in the return line, not sure how this allows more fpr if it has to go thru the stock one first. Second was blockoff then external, but I have also read that there is issues with not regulating the fuel correctly something to do with the little hangy thing in the diaphram not being there. Anyone have an external and how they set it up.

I looked thru the perameters on the injectors and really only see the volume, the 2 injector flow rates. there is bpw sync and async. The rest seems to do with the o2 which I think I may need to make changes to because I have mid tube headers and the o2 is about 12-14 in downstream of where the stock one was. It is 3 wire and heated.

One other thought is I have a 50mm bored sb tbi. I have also read there may be tuning needed for this because of the extra air but nothing on what is needed to be changed, should I just look at a bigblock bin and see what is different for flow characteristics, there are probably only a few that need changed if anyone knows what they are that would be awesome. gonna get a bin now and see.

I was thinking this motor was aproxx 350hp & 400-415 tq but after reading a few setups with dyno results of very similar basically all the same but cam and cam is maybe .01 to .04 higher lift I am seeing 380-420hp. again none were the same and just est of what I think I have. So with what they place I bought the injectors says the injector flow is possibly being off and possibly having a little more power than I thought this could be why I still do not have enough fuel pressure and why the VE table is going beyond 100 in the spreadsheet.

[dave w]

Thanks for all the info, guess there is no spring for the 20-26 range, there used to be a gold one that would do 16-26 from what I read but have not seen one. So I guess my options are the big block injector that is 80-85# with a stock spring at about 15-16psi from the excel spread sheets calculations or get an external vfpr. I have the blockoff for the fpr and the special adaptors for the tbi so I can use 6-an fittings. If I go the route of external I have heard multiple different setups, keep your fpr but add the external in the return line, not sure how this allows more fpr if it has to go thru the stock one first. Second was blockoff then external, but I have also read that there is issues with not regulating the fuel correctly something to do with the little hangy thing in the diaphram not being there. Anyone have an external and how they set it up.

I looked thru the perameters on the injectors and really only see the volume, the 2 injector flow rates. there is bpw sync and async. The rest seems to do with the o2 which I think I may need to make changes to because I have mid tube headers and the o2 is about 12-14 in downstream of where the stock one was. It is 3 wire and heated.

One other thought is I have a 50mm bored sb tbi. I have also read there may be tuning needed for this because of the extra air but nothing on what is needed to be changed, should I just look at a bigblock bin and see what is different for flow characteristics, there are probably only a few that need changed if anyone knows what they are that would be awesome. gonna get a bin now and see.

I was thinking this motor was aproxx 350hp & 400-415 tq but after reading a few setups with dyno results of very similar basically all the same but cam and cam is maybe .01 to .04 higher lift I am seeing 380-420hp. again none were the same and just est of what I think I have. So with what they place I bought the injectors says the injector flow is possibly being off and possibly having a little more power than I thought this could be why I still do not have enough fuel pressure and why the VE table is going beyond 100 in the spreadsheet.

Attached is the PE Active AFR's for a 16197427 Daily Driver.

It would be awesome to compare AFR's screen shots from other tuner members. I think posts with data are the most helpful for everyone wanting to learn tuning.

dave w

[typhoonss92]

daily driver in my case. Well my truck see's maybe 5-6000 miles a year. 90% is highway miles and the motor is 2yrs old. ultimately this will be a toy almost at that point maybe 1 more year. Then a saturday fun driver and the track. only see's 93 octane since I built this motor and usually see 13-15mpg depends if I go past 50% throttle.
I am looking on the site and around the web is there a 7.4L bin for $0D so I can do a compare with my bin just for the throttle body air difference between the stock and the 50mm bored one I have. I have seen a few but $0E so can't use the compare function.

[dave w]

daily driver in my case. Well my truck see's maybe 5-6000 miles a year. 90% is highway miles and the motor is 2yrs old. ultimately this will be a toy almost at that point maybe 1 more year. Then a saturday fun driver and the track. only see's 93 octane since I built this motor and usually see 13-15mpg depends if I go past 50% throttle.
I am looking on the site and around the web is there a 7.4L bin for $0D so I can do a compare with my bin just for the throttle body air difference between the stock and the 50mm bored one I have. I have seen a few but $0E so can't use the compare function.

$OD is for the 4L60E, $OE is for the 4L80E

The factory did not use the 4L60E with the 7.4 liter.

Using two instances of TunerPro (side by side) is required to compare a $OD .bin file vs. $OE .bin file. Parameters from a $OE .bin file can be copied / pasted into a $OD .bin file.

dave w

[typhoonss92]

so after reading about tbi injectors and their vast difference in flow rates for the same injector size and thinking about the 65# injectors I have. even though the place I bought them said the flow is 73 @ 12.5, I rethought this and tried 70@13psi with the bump up to 21psi is about 88. I put that in the injector flow in the chip and it makes a huge difference, I also now get 75dc% at max rpm over 60dc% I was getting. I still think I need a little more fuel pressure but debating on how I will go about that since there is no spring between 23-27psi range, bigger injectors or external vfpr. The only thing I see kinda odd is idle map at 50-60 maxes out the ve table, actually above but it wont go that high. The other thing I am working on now is dfco. It seems to surge off throttle in deaccell. Is there any advice on the closed throttle timing table or should it be the saame as the open throttle table.

[brian617]

I still think I need a little more fuel pressure but debating on how I will go about that since there is no spring between 23-27psi range, bigger injectors or external vfpr. .

I'm running the 94-95 big block spring @ 22 psi with the matching pump in the tank.

[dave w]

Anything with a 7.4 and the 7427 used a 46 lb/hr injector @ 28 psi. Barely enough fuel to support a stock 5.7 Vortec much less anything making any power at all.

I use 14.1 stoich on our E10 here. The fuel trims always seem to fall into line more easily as do the WOT air/fuel. 12:1 around peak torque and lean out to about 12.6:1 at higher rpm.

The link to gearhead-efi TBI injector flow rates: http://www.gearhead-efi.com/Fuel-Inj...d-part-numbers

17104288 - Pink / Purple - 46pph @13psi - 7.4L / 454 - 94-95 *NOTE: Came with 30 PSI regulator used @ 26-32psi for 67-72pph

17084304 - Black / Blue - 74pph - 7.4L / 454 - 91-93

Daily Driver ... hmmm what does that really mean???

dave w