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Quick Maf and tune question?

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Old 06-16-2010, 03:57 PM
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Default Quick Maf and tune question?

I have a Stock headed 383 stroker Ls1 12-1 compression , 240-244 602-611 in a 6 speed car with a 9 inch...it is curently tuned only on speed density and it runs like $hit! horrable gas milage, horrible drivability...and detinates over 4500 rpms...yes i know the shop that tuned it should be burnt down lol...but heres my question...im goin back to Mass air, and have herd all the 4.8-5.3-6.0 trucks use the same maf as ls2 cars? is that true? i have all ready waisted 80$ on a "Broke" ls2 mass air meter...so im wondering if i can go cheap and pick one up from a salvage yard...my second question...its a 12-1 compression motor, a buddy of mine scaned it and there are a few boxes in the timing window set at 31 degrees?! is that as crazy as i think it is?...iv been told it should tune out around 24 degrees?

Thanx for reading
Old 06-16-2010, 04:30 PM
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bump...any body?
Old 06-16-2010, 05:53 PM
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Why would you go back to the MAF? That isn't going to fix the lousy tune... Just get a good SD tune and you'll be fine. And the timing is high like that in the low gram/cyl areas of the table - so it depends on where he was looking...

Do you have the tune pulled out of the PCM with a tuning software program? If yes, which program?
Old 06-17-2010, 11:29 AM
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If you do go back to a MAF you will still have to calibrate it with a wideband...

If you stay in SD you will have to calibrate the VE with a wideband...

If you do decide to run a MAF then you will still need to calibrate the VE also.

Like BLKO2WS6 suggested, stay in SD and get the tune fixed (VE, OLFA, PE, timing...) you'll be amazed at how well it will run.
Old 06-17-2010, 12:26 PM
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lol im aware...i didnt mean i was gana slap a maf on it and nothing els...i ment throw a maf on it and get it retuned...i live in stl and from every one iv talked to, no one around here can tune SD worth a crap ...and i realy dont like that in diff weather conditions the car could run great, or crapy...here in Mo it gets super humid! and seems to bring out the worst in SD tunes ...the tune was pulled by HP tuners software, im not a tuning wiz at all...but it looked like the 31's were sporaticly placed lol
Old 06-17-2010, 12:58 PM
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Very few can tune one in speed density mode to where they do everything right. I undo that stuff all the time. Correction tables, like IAT, etc, have much more influence with the fueling in speed density mode than MAF. Hard to get the vehicle in all different conditions to do those calibrations in a single day. I would use the 85mm 5 wire truck MAF if it were my car.
Old 06-17-2010, 01:06 PM
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so the 85 mm truck maf is basicly the same as the 85 mm ls2? that was my biggest question lol i allready have the piggyback from the broken ls2 maf i bought lol
Old 06-17-2010, 01:28 PM
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Originally Posted by Stroker T/a
so the 85 mm truck maf is basicly the same as the 85 mm ls2? that was my biggest question lol i allready have the piggyback from the broken ls2 maf i bought lol
Yes sir.
Old 06-17-2010, 01:33 PM
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Originally Posted by Ed Wright
Very few can tune one in speed density mode to where they do everything right. I undo that stuff all the time. Correction tables, like IAT, etc, have much more influence with the fueling in speed density mode than MAF. Hard to get the vehicle in all different conditions to do those calibrations in a single day. I would use the 85mm 5 wire truck MAF if it were my car.
x2 I am not a fan of SD on most setups. If you are still flowing limited air, no need to convert to SD.
Old 06-17-2010, 01:40 PM
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lol its a weind intake on stock ls1 heads...flow is at best, limited lol

Thank ya much, replacing a blown head gasket at the moment...that i think was coused from the detination ....maf and a tune hopefully early next week, this car is gana be sick for having stock heads lol
Old 06-17-2010, 04:15 PM
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Originally Posted by Ed Wright
I would use the 85mm 5 wire truck MAF if it were my car.
I agree. I still run a GM 85mm MAF for my setup. Though I've been thinking about SD because I still use the 98 PCM which is maxed at 11250 hz but according to the scan tool I routinely see values much higher than that at WOT.




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