GTC's folder-Looking for gtc for 427 SB Ford

[94GT427]

I was wondering if anyone has a similar setup to mine (below) that has a good street tune with the XFI. I've been having some issues trying to get a good final tune for the street, I repeat street. It would be nice to compare what I have to a good street tune.

It goes pretty good, 450hp & 476 ft-lbs at the rear (91 octane (with 10% ethanol) and am at 7,000' in elevation, decent idle, pretty smooth pulls through the RPM range, 30+mpg at 75mph cruise, but I know some things just aren't really right, ie choppy VE & Spark tables (not too smooth).

It would be nice to see an area that would have a bunch of GTC's just for comparisons. Thanks

Some of the 94 Mustang/engine is setup as follows:
427 sb Ford-Dart block NA
Cam: Bennett 3018F-3288R 112
Intake lobe 242 @ .050 .366 LL
Exhaust lobe 252 @ .050 .366 LL
Lobe separation 112
305009 FAST DualSync Billet Dist. w/ comp. gear
MSD 6AL
42lb injectors @ 50 psi from Aeromotive A1000 & regulated
90mm Accufab TB
TrickFlow Twisted wedge heads/Trickflow R intake
1 7/8" Kook headers/3" exhaust with x-pipe
Rear gear 3:55 w/ Detroit TrueTrac 8.8 diff
Trans: D & D Perf. BA2 T56
Gear ratios 1-6, 2.66, 1.78, 1.30,1.00, .73, .50

[TurboNova]

Lok at the 350 42# tune in the GCT file folder. It should be close to what you are looking at.

The problem with comparing tunes with someone else is it will not be right for you. Every engine is different not matter what. Even two completely twin engines will have a little different tune sometimes.

Use the interpolate function and try to keep your VE numbers within two of the number before.

[Webby]

Turbonova
I am unable to pm or email you due to low post count on here.
I have some basic questions on bank to bank EFI that I would like to ask you. I am UK based so telephone is not cheap. If you don't mind could you pm me with an email address? If you do mind then I understand completely. rgds Webby

[bluzman2004]

450 HP and 30+ MPG... I would say you got in the ball park.

I would think for the street, if you just do like TurboNova said to smooth the transitions out a little, the live correction will go a long way. Just make sure you have some decent a/f targets and you should be fine.

[TurboNova]

my e-mail brian@brianmacy.com

[94GT427]

Lok at the 350 42# tune in the GCT file folder. It should be close to what you are looking at.

The problem with comparing tunes with someone else is it will not be right for you. Every engine is different not matter what. Even two completely twin engines will have a little different tune sometimes.

Use the interpolate function and try to keep your VE numbers within two of the number before.

Thanks Brian,
I have looked at the 350 42# tune as well as all of the others, and yeah I have the understanding that all engines are unique unto themselves. Mine is so different, the following are some basic differences:

First I had to change the scale on the MAP at the low end down to 5, 12, 18. 24, 30, etc. just to tune an exhaust/decel. backfire and downhill cruise/coast drive train jerking out. It's a really good are day if my MAP maxs. out at 78 kPa.

I had to "dig a VE hole" and low Spark area to get the thing to idle at 1000 rpm.

Then someone trashed the decel. area of the Spark table, I just about have that back to good working order now. They did clean up the downhill cruise/coast area timing. I just need to blend the two areas back into each other.

To stop it here, the VE and Spark table graph are interesting (to say the least) at this point and I have not seen anything like mine anywhere. I just wondering if I have gone haywire here.

Thanks for the VE table tip.

Thank you too Bluzman,
I am not even using the closed loop mode anymore. Unfortunately, I did not stress the point of needing a street tune from the engine dyno guys. My a/f table came 13.5:1 across the board and have realized through a little dyno time that my engine needs to go from 12:1 to beyond the limits of the O2 sensor, idle only and I'm assuming it's the open exhaust causing the high reading, any more fuel and the plugs foul really quick.

I am watching my a/f ratio closely though. I'm running anywhere from 12.5:1 to 13.5:1 under an excelleration load normal driving (for an old man, just to 5000-5500 rpm, maybe 6k plus sometimes )

[TurboNova]

1. To start this thing sounds like a mess. From your cam and intake info, this engine will run very well on the 350 42# tune in the GCT folder if it is switched to your firing order, cubic inches ect.. The acutal VE and other stuff should be really close.

2. If you are had someone engine dyno you a tune it will only be good at WOT and not cruise ect. You can't do that on an engine dyno.

3. What is your exhaust setup? How far past the 02 do you have exhaust? I have an idea it is short and at idle you are getting exhaust pulses in and out of the headers showing leaner on the O2 than you really are.

4, If you are running a 6 speed you will have to always run closed loop because the load changes every gear and the 02 will have to adjust for the amount of fuel you need. You will have to pick a gear like 3rd and tune for that at different throttle positions until you get as close to 0% correction you can. Then the rest of the gears will add or subtract fuel as needed by the O2 sensor.

5. You should not have to change any of the map KPA numbers on the left of the VE table with the intake and cam you have. Instead you need to change the VE numbers to reflect what you want. If you have popping out the exhaust it is either just the exhaust or usually an overly rich condition on decel that needs to be tuned out. With short exhaust this can also be skewed.

6. It sounds from your post the O2 sensor isn't getting a good reading because it is too close from the end of the pipe.

Send me your tune and a log and I will see if I can point you in the right direction.
brian@brianmacy.com

[94GT427]

Thanks, I'll send you a *.GTC, but I won't be able to get a log for a couple days, less than 10 degrees here today and my laptop battery hates the cold. What sensors would you like to see in a log and driving conditions/gear(s). I can drop or rise 2000' in elevation within 15 min. of where the car is parked.

1. "sounds like a mess", agreed!
2. Ok.
3. Exhaust: Modified Kooks 1 7/8" primaries to 3" collector, the O2 sensor is about 4" from the tail end of the collector and mounted about 40 degrees radial above horizontal. I have 3" pipe from there back about 26" to an X-pipe, then MagnaFlow 14239, (perforated stainless tube, 14" case, oval) and dumps after the mufflers, dumps are right in front of the rear axle.
The O2 sensors are about 6'-2" from their bung to the dumps.
4.Oh, new info. here.
5.I'll let you see what I did. It was the only way I could get down to "the overly rich condition on decel" so as to tune out the area that was causing the backfire.
6. Maybe
Thanks again

[TurboNova]

Send your GCT for now, don't worry about an elevation change you are not close enough yet to worry about it,

If you have full exhaust already then do you have any exhaust leaks before the O2 sensor?
Are the headers slip on collectors or are they welded on.

The tune you started with came from one the engine builder did on the engine dyno? Have you verified the timing to make sure the crank matches the Fast program?

You could take me a log just warmed up at idle sitting there and that will help to start.
I can change some things based on that from the sounds of it.

[94GT427]

I do have some minor exhaust leaks right after the collectors and yes they are slip on collectors.
The original tune came from the engine builder and I have verified the distributor is phased correctly and the timing matches the FAST program.
Not sure about cam timing Bennett set up, but was told to be sure that the timing read 36 degrees on the timing light, as well as the original spark table was almost all 36 degrees. Started just fine, didn't run well at that point.
Also, this is a 10.5:1 compression engine,