5.7 tbi - larger cam tune advice needed

[CDeeZ]

Do you have a wideband?

[stew86MCSS396]

4.3, 5.0 and 5.7 all share the same throttle bore size. Some may beg to differ but you’re probably good on the air side but if you’re using the 5.0 injectors, you might want to jack up the pressure or go as far as running bbc 80# injectors. I believe ANLU is a 5.7 bin that uses an L98 cam and cop car injectors. Need to work the VE1 and VE2 to get the BLMs dialed in. Your cam is going to idle in the 50 kpa range whereas a stock cam will idle at 30 so your stock tune is gonna feed the engine using the 50 kpa range making it rich. Can you emulate? I would emulate, open a history table most recent and take fuel out of the VE in the cells it idles in. From there datalog and clean up the rest of the VE.

[Fast355]

4.3, 5.0 and 5.7 all share the same throttle bore size. Some may beg to differ but you’re probably good on the air side but if you’re using the 5.0 injectors, you might want to jack up the pressure or go as far as running bbc 80# injectors. I believe ANLU is a 5.7 bin that uses an L98 cam and cop car injectors. Need to work the VE1 and VE2 to get the BLMs dialed in. Your cam is going to idle in the 50 kpa range whereas a stock cam will idle at 30 so your stock tune is gonna feed the engine using the 50 kpa range making it rich. Can you emulate? I would emulate, open a history table most recent and take fuel out of the VE in the cells it idles in. From there datalog and clean up the rest of the VE.

That cam probably idles in the 60-70 KPA range. Probably not much more than 12-14 in/hg of vacuum compared to the stock 305s 20-22 in/hg. Stock 305 HO cam idled about 50 kpa in the 305 in my old 1983 G20. 10:1 355 with a Hotcam I recently tuned idled at about 60-65 kpa in or out of gear with a 3,000 stall in the TH400.

[stew86MCSS396]

@ fast355 hey thanx for your insight as I’m still getting my feet wet. One day I get to wear my big boy pants!

[bdads]

thanx for the help everyone,,,

I was using my snap on scanner also to see as much info while it was running---

so no- I don't have a wideband o2 -- but was reading with the scanner---

also I was trying to pull some fuel out at idle--- just didn't get it good enough yet--- idle did seem to have about 14 in/hg of vacuum ,,,

[bdads]

much thanks--- that anlu bin got me close enough for it to run,, its the best starting point I have had yet !!!!

[bdads]

how much do you suggest taking out ???? or is there a percentage to try ????

[stew86MCSS396]

Try see if this helps... http://www.gearhead-efi.com/Fuel-Inj...-data-Tutorial!

[bdads]

I got it to idle good and revs to 3500 then breaks up -- sometime pops thru the tbi--- I have the base timing set at 8 btdc ,,, could someone please look at this bin and see if something looks out of place to cause this ???? thanks-- steve anlu-2cd mod.BIN

[stew86MCSS396]

If you’re using the L03 injectors with stock fuel pressure, you’re probably going lean. Do you know which injectors you’re using and what your fuel pressure is?

[bdads]

stock injector-stock pump- will check pressure later today--- this seems to just happen at wide open throttle-- if I open it up easy part throttle it revs right up to 5000