Joe Lynch

ABACO won't have their GM meter ready for a couple of months. Granatelli looks like stock range only, frequency convertor for the Ford MAFs not ready yet.

Does anyone know where can I get a GM style MAF with 50% more range than a stock one for an '05/'06 blower car that is pegging out the stock MAF?

Joe

0foff667

The maf really isn't the problem, its the hardcoded limit in the pcm, GM got wise & upped the limit for 08' LS3's.

-Bill

Joe Lynch

Bill--

Then can we do it like we do on the Fords? Scale the MAF to span the available range (512g/sec) and ratio the injector slopes to compensate, why wouldn't that work?

On '03 - '04 Ford cars, we do this all the time. You have to make sure that everything else gets scaled that needs it as well, but hard-coded flow limits shouldn't necessarily stop us from putting in a larger MAF.

0foff667

You can read some more info about it here http://www.hptuners.com/forum/showth...ight=hardcoded however with our new custom operating system having to do that will be a thing of the past or by lesser Tuning software packages

http://www.hptuners.com/forum/showth...hlight=devtest we should have at least one corvette cal in beta in the next few days, all of the Australian calibrations are complete.

Joe Lynch

OK, I can use a standard MAF and extend the upper limits on the MAF Hz using the new operating system? That would work on this car, since it is just tagging the upper end. At least at this altitude. The car will run lean on a cool day at sea level the way it is.

I am just going to lower his rev limiter until you guys come out with something I can use. (He has a centrifugal blower.)

Joe Lynch

I'm going to use this meter for now. The car owner has already changed the pully on this car without letting me get him some more range first.
http://www.powrmax.com/PowrMAF%20100.html

5 Liter Eater

Thats a nice MAF but as Bill said it probably won't help much if at all. The larger MAF will hit the 512 g/sec limit at a lower frequency. If you artifically lower the IFR that will necessitate lowering the MAF table to compensate which will buy you more room but you will then bump up against the 12200 Hz frequency limit.

If it's an '05 you can use the custom 2 bar speed density OS. If not then until the custom OS comes out to extend the MAF table (s) all you can do is see what RPM he maxes out the MAF frequency (12200 Hz) or flow (512 g/sec) (whichever comes first). Then start increasing the PE linearly at that RPM to add more and more fuel until redline. When it gets colder though he will be making more boost and the tune will be lean.

Joe Lynch

This meter will only output about about 9000 Hz at the mass air rate that the current meter shows 12,200 Hz. I should be able to scale the MAF curve and the IFR to get to 11.5-12.0 AFR and have plenty of room left on the meter at sea level and cold ambient. I will post the datalogs when I am done.

We do this on the Fords all the time that have a 64 lb/min hardware limitation.

Joe

5 Liter Eater

Please do. Looking forward to the results.

0foff667

Just to let you guys know we now offer that custom operating system for the newest 2007 Corvette calibration in the newest public version.

5 Liter Eater

Joe,

I'm not a fan of the VE tuning on the gen 4's (especially the E40's). I'd much rather run a MAF, so whatever I can do to retain it I'm for. I ran some numbers and am more interested in your experiment with the MAF than ever. I don't have any 4th gear pull dyno data logs but the few street logs I've taken show a peak frequency of 11800 Hz and 462 g/sec at 7.5# of boost (I'm logging boost with my 2 bar sensor and a custom PID). So clearly I'll run out of frequency before I run out of flow. Technically I could run a MAF right now but any more mods or some cooler weather and I'm hosed.

As we know we can artifically lowerer the IFR to artifically lower the MAF flow/frequency but this doesn't get around the frequncy limit because the real flow is the same. By increasing the MAF size the there should be more "real" flow per frequency. The PowerMax MAF reads 512 g/s at 10625 Hz whereas the stock ('05) MAF table reads 512 g/s at 12200 Hz. That ~1500 Hz will go a long way with the exponential nature of the MAF curve and if you hit the 512 g/s limit again you can just lower the IFR some more.

So let us know how it goes!

Joe Lynch

Bill--thanks for the note. The car I am tuning just barely pegs the stock MAF at 12200 Hz in a blow-through arrangement. All that matters to me is to get a meter on the car that won't hit 12,200Hz. Once that is done, the rest is math. This 103mm housing with the new sensor should give this car enough range. If not, I will fabricate a larger tube and use it with this new sensor. I have built several Ford meters using a similar slot style sensor (but with 0-5v output) in a custom tube. You can get any range you want simply by adjusting the cross sectional area of the meter tube. This is easy to do with the slot meter. I have sources for both steel and alum sensor bosses to put on any size tube I want. I use the PMAS HPX sensors on the Fords but they don't have their frequency output sensors finished yet.

The sensor signal on the Ford type is very clean even in a blow through arrangement. I hope this Hitachi frequency type works as well.

Should have the parts for this car next week. Here is a picture of the fabricated air tube on my turbo Mustang, placed to give just the right range.
http://pages.suddenlink.net/joelynch..._installed.jpg


Joe

Joe Lynch

Here are some pictures of the HallTech 103 mm housing with the Hitachi LS7 sensor. To the left is a Ford replacement PMAS model HPX sensor that the Ford tuners typically use in blow-through location on blower cars.

http://joelynch.smugmug.com/gallery/...31110566_J6DU6

I was pleasantly surprised to see how similar the two sensors are, yet the output signals are different.

The output signal for the Ford meter is 0-5vdc but the two meters are interchangeable in the housings. The connectors are different as well. The adapter shown allows us to build a tube any diameter we need to get the range needed for a given car. The PMAS HPX sensor is ranged to work in the 3-3.5 inch intercooler discharge tube common to many supercharger kits. This is what we need for the GM cars, then just weld in the adapter to the kit tubing and wire it up.

I've installed 5 of these PMAS sensors on Ford blower cars, with appropriate MAF curve generation from scratch and modifications to IFR and timing tables.

I get the C6 blower car back on Wednesday to install the meter in the photographs.

Joe

5 Liter Eater

Thats a nice piece. Right now for me it's easier to just get the whole new housing and sensor. I went ahead and sprung for a PowrMAF today.

Joe Lynch

I should have some feedback for you on how the meter works on the Procharged car on Thursday. I am putting the complete HallTech housing and meter on the C6. I would only need the metal adapter in the photos for a sensor scaled to work in a 3.5" tube.

I am just going to move the GM harness pins over to the connector for the HallTech meter just like shown on the website. Will probably use the couplers that are currently on the car. I hope. If not, there will be a little delay.

Joe Lynch

foff667--

OK, now I am confused. I have 2.22 and looked at the '05 tune file under the OS tab and it gives me the options of the 2bar sd tune and also the 15000 Hz extension.

It appears that I can use the extension simply by flashing (entire) the car with the 15000 option selected and then downloading it again to see that the option has been installed, is this correct?

Then the 2 bar SD tune option is a separate option requiring an SD license? How many credits?

But I don't really need the sd option of the 15000 Hz change to the OS gives me the head room?

I was thinking, possibly in error, that I had to wait for the 2.5 bar OS to get the 15000 Hz option so that is why I was going to go with the meter now. Was I wrong?

5 Liter Eater

Joe, are you talking about the MAF Freq Patch? If so the 15k Hz it references is misleading. There is a bug where the MAF actually maxes out at 11,500. The patch just allows you to use the entire MAF table which still maxes out at 12,200 on the E40's. On other vehicles the patch appplies to the MAF table may go up to 15k Hz, so it is misleading.

http://www.hptuners.com/forum/showth...maf+freq+patch

see5

The 08 E-38 OS has a much wider scale for the MAF in anticipation of the LS9. The 08 LS3/7s also use the GM 15865791 sensor which is supplied with the PowrMAF 100.
Unfortunately the os can not be applied to earlier E-38s.

LABELS MAF Frequency Conversion (Grams/Sec)
Hz Value
0 0.389765
150 0.389765
300 0.389765
450 0.389765
600 0.389765
750 0.389765
900 1.025958
1050 1.700490
1200 3.494886
1350 3.890867
1500 4.438219
1650 5.136941
1800 5.987034
1950 6.988497
2100 8.141331
2250 9.445535
2400 10.920454
2550 12.579458
2700 14.414942
2850 16.469835
3000 18.748518
3150 21.245575
3300 23.970362
3450 26.917643
3600 30.087465
3750 33.482204
3900 37.100533
4050 40.958755
4200 45.120026
4350 49.549770
4500 54.247997
4650 59.214699
4800 64.640617
4950 70.448959
5100 76.611755
5250 83.143051
5400 90.055779
5550 97.338379
5700 104.984428
5850 112.992119
6000 121.397011
6150 130.430023
6300 139.983246
6450 150.056656
6600 160.645737
6750 171.664383
6900 183.166779
7050 195.152908
7200 207.590057
7350 220.468414
7500 233.803955
7650 247.782623
7800 262.518555
7950 277.900299
8100 293.844818
8250 310.371948
8400 327.387024
8550 344.738281
8700 362.599182
8850 381.681396
9000 401.485687
9150 422.261963
9300 445.866180
9450 467.670868
9600 490.191864
9750 513.441040
9900 537.430359
10050 562.171631
10200 587.676819
10350 613.957764
10500 641.026428
10650 668.894592
10800 697.574280
10950 727.077271
11100 757.415588
11250 788.601013
11400 820.645447
11550 853.560852
11700 887.359070
11850 922.052002
12000 957.651611
12150 994.169678
12300 1031.618164
12450 1070.008911
12600 1109.353882
12750 1149.665039
12900 1190.954102
13050 1233.233032
13200 1276.513672
13350 1320.808105
13500 1366.127930
13650 1412.485352
13800 1459.892090
13950 1508.360107
14100 1557.901123
14250 1608.527344
14400 1660.250366
14550 1713.082275
14700 1767.034912
14850 1822.120117
15000 1878.349731

RWTD

And, unfortunately, GM didn't give the '08 Z06 calibration the extended range of the LS3.

I just submitted an '09 Z06 factory calibration to Chris and Bill at HPT, so hopefully GM did such for it (fingers crossed), but right now I tend to believe not.

RWTD

BINGO! Joe, make absolutely sure you apply the MAF patch for that '05, otherwise you'll find out real quick like what it's like to revert back to the 1st cell of the low MAF range while under WOT and heavy boost. It's not pretty!