yeah thats a big one. not too big though.
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yeah thats a big one. not too big though.
Oregon Sand Dunes tires!
I've been doing more assessment work on the 454 Suburban. The timing is set to 10 degrees BTDC with the ESC connector unplugged. The injectors are 17104288 with about 30 PSI. Looks to be factory 1994 ~ 1995 454 Throttle Body that is on the engine.
My current plan is to set the timing to 4 BTDC and program a near stock fuel and timing table. The data log and see what changes.
I'm thinking about using some 305 injectors, but I've never run 305 injectors at 30 PSI. I'm concerned that maybe there is a potential problem with 305 injectors at 30 PSI?
dave why use 305 injectors, a set of early 454 injectors will support a lot more fuel. I plan on a set of 5285231 injectors for my 355.
The early 454 injectors were supplied with ~12 PSI or so. I think starting in 1993 maybe 1992, the 454 injectors were supplied with ~30 PSI or so. My thinking is the later 454 injectors would flow about 45 lb / hr with about 12 PSI, and about 78 lb / hr with 30 PSI. My thinking is to use 305 injectors, which flow about 50 lb / hr with about 12 PSI, so with 305 injectors at 30 PSI I'm guessing the flow would be close to 88 lb / hr.Quote:
Originally Posted by jim_in_dorris
I'm thinking the injector number you posted is actually 5235231, which are early 454 injectors that flow about 85 lb / hr or there about with 12 PSI.
dave w
An update on 305 injectors, 5235279 are rated at 40 lb / hr not the 50 lb / hr I was thinking. I might try some 55 lb 5.7 liter.
dave w
yeah, 5235231 after I looked closer with a magnifier. OLD EYES LOL!!! The table I have show 90 # at 12 PSI for the older BB injectors. At 28 PSI, they will support 500 HP according to my spreadsheet. To support 400 hp with 55# 350 injectors, you need 48.5 psi according to my spreadsheet.
Your supporting WOT with correct AFR now. Why change?
I'll be handicapped here for awhile as my laptop died yesterday... close to burning final chip for a tune in my garage...
But thoughts were any specs needed for those injectors would be in 94-95 bin, I'd guess calculate BPW from 4.3L injectors at 12.5 PSI to 30PSI for that as it won't be in $0D-$0E but any other change would be so that part is done.
I think I'll install a set of early 454 80 lb. / hr. injectors with stock spring, and see what that does. I have a 15 lb. spring if needed. I'm not sure the fuel pump is rated for a steady diet of 30PSI? I think it makes sense, for the vehicle owner, to have injectors that are for the correct make / model / year / engine size.
dave w
I agree, those injectors are known to be good with those pressures and the ECM system. It's the route I would go. Proven is always a good route...
Never have done hands on with the newer smaller higher pressure injectors? But since they came that way from factory should be a good route as well for close to stock engine. Don't know how thery would react with more pressure or how much?
You going to fix the knock circuit?
"Mystery" bin is ASDU with small changes. Basic stuff... injector constant, max BPW, main spark, main fuel, PE AFR and target idle speed. 317 bytes total.
Edit: As Mark mentioned, cal is out of fuel early on. VE in main table has values 20% to 30% greater than stock. Cal is out of fuel but engine may not be. Injector constant is larger than any stock 7.4 cal which limits fuel. Very large difference... why? Wrong injector size during calculations? Screwed up and assumed later injector flow rated at 12 psi instead of measured 30? Engine obviously swapped in (454 + 700R4 = dead 700R4). Was 350 running on 454 TB and I briefly before larger engine put in?
High spark peak at 1k rpm and idle speeds in the 750 rpm range. Auto trans doesn't typically like high idle. Hopefully that converter is pretty loose, esp. with those tires. Tight converter and high idle plus big drivetrain means engine is constantly fighting to "drive" truck at idle. Bad combination. That would mean high spark plus high idle is just trying to keep engine idling in gear. Much harder to tune. Still doable, use IAC park/neutral adder adder to increase idle speed in drive. OTOH if loose converter then fast spark ramp is good idea. Snap hard as soon as throttle is opened to give "hit" and help get truck moving. But tailor it to match stall speed and back it down if throttle is released and MAP comes back down. "Digital throttle" effect (you know, all off or all on, no in between) is a result of too much spark too soon in too many cells.
I would not change injectors. 30 psi injector does better... better atomization, better burn. That's just me. I don't know how the truck is built but if the engine is near stock with maybe headers and mild cam, converter's loose, and truck isn't street driven very often I'd be looking forward to it as an easy job. Hardest part is connecting DVOM and scope to get "real" readings from the sensors.
Happy tuning.
Thanks for the input! I was thinking the mystery .bin was AMUR, similar to ADSU?Quote:
Originally Posted by 1project2many
There is an aftermarket fuel pump and fuel tank, not sure what the ratings are for the fuel pump inside the gas tank. I think there is a very real possibility the fuel pump might need an upgrade? I can measure pressure, but figuring flow is not something I've done. The local "Dyno Tuner" will not tune a TBI 454 unless the stock fuel pump is upgraded. I'm hoping that the 80 lb. hr. injectors, with stock 12 PSI spring will work out, according to the WBO2.
dave w
Scan ID matches ASDU. Any ID is possible but high number of similarities between ASDU and mystery .bin during file compare probably isn't coincidence.Quote:
Thanks for the input! I was thinking the mystery .bin was AMUR, similar to ADSU?
Pump flow is fairly easy depending on specs. Gallon jug plus stopwatch... turn on pump and measure time to fill specified quantity (quart works good). Extrapolate quarts/min to gallons/hr. Flow at pressure is similar but requires regulator plumbed in. More important may be deadhead pressure. Install pressure tap at filter then pinch off or close supply line before TB. PFI style pump generates 80 to 100 psi pressure. GM / Delco TBI pump generates 15, maybe 20 psi max. Dyno guy might be reminded that stock and near stock 454 is not a hp monster. A Vortec 5.7 makes more power than a stock 7.4 TBI engine. Torque peak and BSFC is higher for 7.4 but gallons / hr is not.
I thought I'd share a pic on how I'm working on / gaining access to the engine compartment on this lifted Suburban.:laugh:
dave w
An update. I've installed the 80 lb. / hr. injectors. I've installed the 15 PSI spring. The attached files are the current .bin with BPW 138. I've also attached two .xdl files, one with BPW 144 and one with the BPW 138.
dave w