6E only seeing 201 g/s at WOT

Reply Subscribe

Thread Tools

Search this Thread

Sep 12, 2007 | 09:27 PM

2new2funny

Thread Starter

Member

Joined: Mar 2004

Posts: 165

Likes: 0

6E only seeing 201 g/s at WOT

Title pretty much says it all. This flow rate is in the upper 5th MAF table.
I'm running an L98, pretty much stock with the exception of a ZZ4 cam.

Any ideas of how I can get into MAF table 6? Am I right to assume that there's still performance left on the table if I'm stuck in MAF 5?

Last edited by 2new2funny; Sep 12, 2007 at 09:28 PM. Reason: detail

Sep 13, 2007 | 08:41 AM

tequilaboy

Member

Joined: Sep 2007

Posts: 350

Likes: 15

Re: 6E only seeing 201 g/s at WOT

200 gm/sec sounds about right for a near stock L98. With more mods you should see the airflow increase.

I'm flowing about 240 gm/sec now with SR/bigmouth/Comp 503/long tubes/stock 113 heads, etc.

The cam was worth about 20 gms/sec. The SR/bigmouth combination was worth another 20 gm/sec.

Sep 13, 2007 | 12:31 PM

Grim Reaper

TGO Supporter

Joined: Jul 1999

Posts: 10,907

Likes: 5

From: The Bone Yard

Car: Death Mobile

Engine: 666 c.i.

Re: 6E only seeing 201 g/s at WOT

It is possible to re-adjust the MAF Scalar Tables to set the maximum to lower than 201 g/s on the top of Table #5 and force it to go into Table 6 if you wish to cause it to go to Tabel 6.

But, you need to also adjust to address C5DF to make sure the table lookup knows to jump out of Table 5 and go into Table 6. As well, you will need to re-adjust the C5EC (the starting point in Table 6 to match the value you set in address C5DF.

Have fun

Code:

        ;----------------------------------------------
        ; MASS AIR FLOW TABLE #5
        ;
        ;  ARG = GMS/SEC  + (256/SCALAR)
        ;----------------------------------------------
LC5DF:  FCB 207     ; TABLE SCALAR
                    ;
LC5E0:  FCB 8       ; 8 + 1 LINE TABLE
        			;
					;  gms/sec    BIN      VDC     #/HR
        			;----------------------------------
LC5E1   FCB 166     ; 134.2     1280     3.66     1036
LC5E2   FCB 176     ; 142.3     1312     3.75     1098
LC5E3   FCB 186     ; 150.4     1344     3.84     1161
LC5E4   FCB 196     ; 158.5     1376     3.93     1223
LC5E5   FCB 207     ; 167.4     1408     4.02     1292
LC5E6   FCB 219     ; 177.1     1440     4.11     1367
LC5E7   FCB 230     ; 186.0     1472     4.21     1435
LC5E8   FCB 242     ; 195.7     1504     4.30     1510
LC5E9   FCB 255     ; 206.2     1536     4.39     1591
        ;----------------------------------------------


        ;----------------------------------------------
        ; MASS AIR FLOW TABLE #6
        ;
        ;  ARG = GMS/SEC  + (256/SCALAR)
        ;
        ;----------------------------------------------
        FCB  255    ; TABLE SCALAR
                    ;
LC5EB:  FCB  16     ;       16 = 1 LINES IN TABLE
        			;
					; gms/SeC    BIN      VDC     #/HR
        			;----------------------------------
 LC5EC   FCB  207   ; 206.2     1536     4.39     1591
 LC5ED   FCB  213   ; 212.2     1552     4.43     1637
 LC5EE   FCB  219   ; 218.1     1568     4.48     1684
 LC5EF   FCB  226   ; 225.1     1584     4.53     1737
 LC5F0   FCB  233   ; 232.1     1600     4.57     1791
 LC5F1   FCB  240   ; 239.1     1616     4.62     1845
 LC5F2   FCB  248   ; 247.0     1632     4.66     1906
 LC5F3   FCB  255   ; 254.0     1648     4.71     1960
 LC5F4   FCB  255   ; 254.0     1664     4.75     1960
 LC5F5   FCB  255   ; 254.0     1680     4.80     1960
 LC5F6   FCB  255   ; 254.0     1696     4.85     1960
 LC5F7   FCB  255   ; 254.0     1712     4.89     1960
 LC5F8   FCB  255   ; 254.0     1728     4.94     1960
 LC5F9   FCB  255   ; 254.0     1744     4.98     1960
 LC5FA   FCB  255   ; 254.0     1760     5.03     1960
 LC5FB   FCB  255   ; 254.0     1776     5.07     1960
 LC5FC   FCB  255   ; 254.0     1792     5.12     1960

Sep 13, 2007 | 04:16 PM

327_TPI_77_Maro

Supreme Member

iTrader: (8)

Joined: Sep 2004

Posts: 1,896

Likes: 0

From: Charles County, Maryland

Car: 2000 BMW M5

Re: 6E only seeing 201 g/s at WOT

Yeah the stock L98 w/ super restrictive intake, and probably low shift points, is probably not strong enough to max out the MAF. Sounds normal for that combo. I ran 2.02/1.6 heads on my 327, with an old school 0.480/0.480 cam, and the MAF was maxed out at 255 by about 5800 (I was shifting at 6300 so I had to bump the PE above 5500ish). This was with a Stealth Ram intake.

Sep 13, 2007 | 07:31 PM

2new2funny

Thread Starter

Member

Joined: Mar 2004

Posts: 165

Likes: 0

Re: 6E only seeing 201 g/s at WOT

Thanks for the replies.

Oddly enough I only broke the 200 mark when I richened up Table 5 by 5% to get better WOT.

Before this, I was running 187. Do I assume that the tune just wasn't quite right and the increase in the g/s reading is just a function of a better tune?

I may increase the table values another 5% and see what happens...

Sep 13, 2007 | 08:18 PM

327_TPI_77_Maro

Supreme Member

iTrader: (8)

Joined: Sep 2004

Posts: 1,896

Likes: 0

From: Charles County, Maryland

Car: 2000 BMW M5

Re: 6E only seeing 201 g/s at WOT

When you "richen" MAF tables you are basically lying to the computer about the meter's readings. The readings went up because you told them to go up. The g/sec numbers are arbitrary, and only reflecting true flow rate when calibrated vs the voltage

Sep 13, 2007 | 10:32 PM

Grim Reaper

TGO Supporter

Joined: Jul 1999

Posts: 10,907

Likes: 5

From: The Bone Yard

Car: Death Mobile

Engine: 666 c.i.

Re: 6E only seeing 201 g/s at WOT

Quote:

Originally Posted by 2new2funny

I agree with 327_TPI that fibbing to the computer (unless you are just testing something and want to see it's affect) is not a good thing. What you really need to do, is tune your engine to a WB O2 and get it to the correct mixture (approx 12.6-12.8).

And as the others have already said, a "basically" stock TPI won't max the MAF at all. That is why GM wasn't concerned about the 255 gm/sec limitation of the 3rd Gen's MAF system - none of their engines at that time were close to maxing the MAF.