DIY PROMDo It Yourself PROM chip burning help. No PROM begging. No PROMs for sale. No commercial exchange. Not a referral service.
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hello i have few questions i got vortech supercharger 6-8 lbs boost my questions are?
how map - kpa work when there is psi on the upper end rpm theres no vacum i have map table convertion like 80 KPA=11.6 psi map and 6.4 vaccum
on Stock l98 the power band maxs out 4000 rpm? i have holly stealth ram cam 580 lift high flow heads, headers ,flow master exhaust with dumps for strip, 24lbs injectors
Were should i start ? i have chip now that was running really well i got the prom for pcm for less and his upper ve vs rpm vs map table shows low 90,s ve in the 90 100 kpa range
ANY HELP WOULD BE GREAT
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I'm going to assume you're using '730 speed density stuff -
The VE table breakpoints are only for anything that is atmospheric pressure or less (vacuum only). Boost is off the table above 100 kPa.
I'm going to be in a similar boat soon, as I too have bought a vortech s/c, and may use it on either a '730 or '165 MAF car, or possibly convert to my company's ECU.
If I'm correct about you using a '730 (and not converted to $58 or whatever), you should definitely use an FMU with a high ratio, and use a boost timing controller to pull ~1-2 degrees of advance out per psi (maybe 2-3 if no intercooler). You can fine tune the A/F ratio with PE fuel (Power Enrichment). You'll probably need to shoot for 11.4-11.8:1 if no intercooler. You should also watch for knock (and also put 0 for the ALDL spark offset), and adjust the PE spark advance down when you see knock.
Or, you could convert to a boost friendly computer, and use a 2 bar MAP sensor, but you'd need bigger injectors. I just picked up a set of 42's for a 355 AFR195s LT4 hotcam superram, and vortech V1 setup. But I'll only use them when I eventually convert to my company's ECU with quasi-sequential injection. First I'll set it up with just an FMU and boost timing retarder, and stock or 28lb injectors.
__________________ -Jeremy- EFI Calibration Engineer, Director of R&D, Software Designer (Fuel Injection Technologies - dianpen.com) - still in China since Nov '04!!!
86 Z28 - rusty, tired, and in storage - 89 GTA with plans, but - also in storage now needs paint - badly, 79 Malibu classic with 91 L98, 4L60, 3.73
Last edited by RednGold86Z; 02-11-2008 at 10:29 PM.
yes its 730 ecm i have fmu and boost controller and have 2-3 out of timing what about ve table rpmvs Map-Kpa in the upper #s like 50 and above
And any input on timing
For the high MAP (50-100kPa), use whatever makes 14.7 at those points. At 100, though, it may or may not actually be 100, because 100-150kPa will be boost on your engine, but the MAP sensor only works to 100 (or 105 or whatever, but not sensing boost).
You can tune 100 with the blower disconnected from the throttle body (don't do that with a turbo though - it might overspeed). Either disable PE and tune for 14.7 (just for tuning the VE, re-enable it when done). Or, set the commanded PE AFR to 12.5 (or whatever you want), and tune the VE until your wideband also reads the same as the commanded.
When boost is full on, with the FMU, watch the AFR and make sure it's never leaner than a safe AFR. If it is leaner, you can fudge the PE to add fuel to make it richer at each RPM breakpoint that you want more.
Watch knock counts for timing adjustments. Avoid knock if you can, but a tickle here and there is inevitable. How much timing depends on compression ratio, air temp, humidity, cam, boost, luck, chance, octane, and chamber design, and water temperature.
Water/meth (windshield washer fluid) injection would also help. Aside from cooling the charge to reduce knock, I've also heard that water molecules act like a catalyst to CO to finish the combustion to CO2 faster during the later 60% of the combustion process which can help power production. Methanol will also richen the mixture some.
VE comes first, always, but you can do it with supercharger connected (but don't tune 100 kPA when doing full throttle + boost, just do it at like 99kPA to be sure you're not using the FMU's enrichment and not in boost). Disconnecting would be the quick way to get the 100 kPA column nailed easily.
That's how I plan to do it, and should be pretty close. The blower might change the VE a tad though, not sure, but shouldn't be much at all (only change would be from the pressure upstream of the throttle, but it's minimal when using a bypass valve).
now needs paint - badly, 79 Malibu classic with 91 L98, 4L60, 3.73 
