05 corvette
13:1 ls2
Full port 243 heads
102mm mid ram intake and throttle body
ss4 GPI cam
TSP log tube headers with x pipe, SLP loudmouth mufflers
I switched to ls3 maf due to intake size. MAF high cal flatlines at 8200hz. is there a way around this or do I need to run in SD? VE is within 4%
Last edited by 1352806038; 10-06-2022 at 05:13 PM.
What do you mean by flat lines? The MAF frequency quits rising? What size tube is the MAF in?Originally Posted by 1352806038
In MAF calibration high, at 6000 rpm, it flatlines. The MAF is in a 4" aluminum pipe.
I guess I am still not understanding the question or rather the problem you think you are seeing. MAF calibration is going to have to be changed when different MAFs are put into different sized tubes. Does the intake tube have a flow straightener screen in front of the MAF?
I have calibrated the MAF as much as i can but anything over 6000 rpm or 8200hz is maxed out. Its an open pipe between filter and tb.
The LS2 MAF table goes to 12,200hz. Looking at a 2005 LS2 MAF calibration now.
Im sorry, at 8200hz it maxes out at 4063.5 lb/h
Thats 512 gms/sec. If you are hitting that, I would look at your displacement and injector calibrations.
Please post a data log and tune file. Something is not right. My 4" MAF on a 383 making 430 RWHP does not get anywhere near the frequency/flow limits. You would have to make over 600 hp at the crank to max the 512 gm/sec of airflow out. Even then you can add/remove additional fuel with the PE multiplier on the top-end.
Gonna throw this out there:
May not apply to your model ....but did on mine
Don't you need to switch 2 or all of the wires around in the maf harness? as their positions are different between ls2 and ls3 plug (or buy the ls2 to ls3/ls7 harness adaptor).
Last edited by goodwrenchdave; 10-17-2022 at 09:59 PM.
When you get the flow screen in the 4" tube I found the 4" Lingenfelter 100mm MAF calibration charts a very good starting point. On my P01 and P59 I did have to fix the IAT calibration curve so that the IAT was accurate. After an overnight soak at ambient temp I found that the IAT, CTS and Trans Temp all read within a degree or two of each other between 40F and 100F so far. So its a good sanity check on the IATs calibration.
https://www.lingenfelter.com/categor...t_Numbers.html
Last edited by Fast4.7; 10-18-2022 at 02:04 PM.
I think you'd have a better result tuning it in speed density.
That cam is quite large and reversion at low loads/RPM will cause havoc on the MAF readings.
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The MAF is so filtered I doubt it. I have tuned absolutely huge cams with a MAF and it works well. I did a 246/254 @ 0.050 on a 110 in an OBD2 LT1 on MAF. My personal 383 had a 232/244 @ .050 on a 108 and ran great with MAF too.
I find speed density more of a pain in the butt with large cams. The VE table resolution being so reduced.
Personally I disliked speed density tunes from day one. My GM TBI was MAF.
Last edited by Fast4.7; 10-18-2022 at 07:28 PM.
You need to scale the tune. You hit the gps limit, so while the maf has plenty of headroom your tune does not. Look into scaling by half. 512 will actually be 1024 and everything will work
GLONASS limit for those running a Soviet tune.
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