Well I just bought Flashscan/tune I have logged using EFIlive since ver.5 and done a few little changes with LS1edit other than that I am new to this game. First off I should give a picture of what I am working with.

99 F-Body
A4
3:73 gears

427 stroker
11.3.1 Compression
244/244 .618 112LSA
Long Tube headers
All the bolt ons.

I was running ok on previous tune but during dyno sessions discovered the shop that built the engine had screwed me on the heads and I was running out of air at about 5600rpm. (no more shops for me)

I changed the heads to TEA Stage 3.5 2.10 x 1.65

This moved the RPM range way up and I was logging some KR and a bit lean. A tuner had me make some VE changes and the car was running pretty good but I felt I needed to get more air into it so I went with the FAST LSX90mm intake (port matched by TEA) and the 90mm FAST TB, along with a 85mm MAF and Lid.

I changed the MAF table to match a 85mm table from LS1tech.com and fired the car up. Needless to say the car runs like crap

LTFTs are +25% both sides max out unless I snap the throttle and then it will fall for a sec then start climbing back up till it maxs out again.

Idle is all over the place, throttle response is also. I did not want to damage any thing so I pretty much slow cruised it home and headed here for advise.

I looked at my VE with the new Flashscan and it looked VERY bad so I played with the smoothing/blending and it made the table look better, (not as good as the Backup table but better. I have not tried it on the car yet.


Where should I start to try to get a handle on this?

Thanks for the help.

Maybe someday I will have something to add to this forum for the other nuts that had to have a 427 in an F-body

 

Make sure this 85mm MAF, is a virgin Delphi and not some
bastard SLP / Pace (or worse yet, Granatelli). Any of those
would be way lean relative to a Z06 or truck cal.

 

Well its one I got about a year ago but it says Delphi on it.


Here is what I went with.

Here is the stock 85mm Delphi/Holden MAF table:
1.57 1.85 2.17 2.55 2.98 3.45 3.95 4.48 5.07 5.73 6.43 7.2 8.02 8.91 9.84 10.84 11.9 13.05 14.27 15.59 16.99 18.52 20.14 21.86 23.66 25.57 27.58 29.71 31.93 34.26 36.69 39.25 41.96 44.87 47.91 51.12 54.41 57.95 61.59 65.38 69.38 73.48 77.78 82.24 86.81 91.66 96.63 101.77 107.16 112.67 118.43 124.38 130.46 136.84 143.34 150.02 156.95 164.02 171.38 178.95 186.66 194.8 203.1 211.66 220.54 229.6 239.02 248.68 258.52 268.77 279.23 289.98 301.16 312.55 324.4 336.62 349.08 362.22 375.66 389.52 404.04 418.89 434.44 450.55 467.05

 

Well, that looks roughly proper but the question is, whether the
MAF is what you think it is. SLP MAF is a Delphi with a resistor,
so is Pace. Just no reason for a stock MAF to be that far off.

I have a SLP MAF in a box around here somewhere. After the
puffy SLP sticker fell off, it said Delphi.

Of course in the lower RPM the MAF is not the whole story. The
pumping characteristics have to be way changed by the new
heads & mondo cam. Have you been into the VE table at all?

If you have +25 trims at idle that's more about VE (though the
MAF is probably whacked down there too). Look to something like
FTC 6, 7, 10, 11 for an idea of how good the MAF based air
reading is. If -those- are +25 then the MAF (or its table) is not
right.

 

Well the lower FTC 6-11 are the ones giving me grief, 17 and 22 look fine. I think I need to look for a known good starting point for the MAF. Also it looks like the Fast 90mm TB is having a problem returning to 0% TP. Guess I will start looking for a MAF and get on FAST about the TB.

 

Anyone know where to get the right 85mm MAF (new) and what the cost is?


Thanks

 

Look for a 6.0L truck MAF used, it's the same part as the ZO6 unit.

BTW - How does that cam idle and run with an A4?

 

Cam use to idle ok in a sick kinda way, never died even with AC on but people just stare at the car with their mouth open. Everything is crap at the moment. I am going to get a known good MAf to start with and I guess I need to start at square 1 and work on figuring out the proper tune for this thing... And to think I have a complete Nitrous kit to put on once I get this mess setup right.

 

Your Ltrims are going to +25 at idle due to so much positive valve overlap with that big cam.

If your Ltrims are ok around 1,500 RPMS and higher, I woundn't be to worried.