[TransAmConvert]

Just looking for a little advice from anyone who has a similar setup to me, i imagine its fairly common. I need some tips on how to get it to run right, especially with my AFC settings. I just put disk 680s in and im having a tough time with them. The car is really running like a dog and it feels like im just missing one little piece. Im starting to run out of patience so i thought id throw it out there to anyone in the same boat.

Ive got:
680cc inj
2G MAS (stock)
16g (small, ported)
Supra SMIC
Hard IC piping
Crushed BOV
255 rewired
2.5" tubular o2 dump
2.5" Exhaust
MBC @ 18
ACT 2100
Revised lifters
150psi compression on all

Anyone have some tips? I want to start having some fun with this thing already!

I have the AFC now close to zero, and i think its way off, but IDK
I also have a logger, but right now im at a loss as to what to do with it until i get into the ballpark so to speak.

Also,
DSMtalk=:rockon:

 

[deem]

What do your data log reading look like when you are having a problam. Have you done a boost leak check?

You would be amazed how one little crack in your TB/ intake gaskets will effect performence.

 

[1998GSTAT]

how much bigger is 680 than 450? compensate in the air flow by the same percentage.

((680-450)/680) * 100% = 34%

Start by making your AFC values around -34% then go from there. I have 550's in and I run -19 at all my lows and -22 to -26 form my hi's

 

[Taboo]

Anyone have some tips?

Yes . Get AFPR. You won't be ever able to tune the car with the rewired Walbro 255, 680cc injectors, S-AFC - and the stock FPR.

 

[TransAmConvert]

Took the car to the track today. I pulled aout a lot of fuel and put the base timing at 2*BTDC. Taboo: Your advice was echoed by many at the track and i plan on getting a regulator and gauge asap.
My best run was a 15.47 @ 94 . Yes, i know i suck.
This is the log from that run, its very interesting. If anyone could give me some more info based on it i would appreciate it a lot.

Once again, you all rock!

LOG:
RPM Knock Timing O2 P/W DC% TPS
875 0 10 0.88 1.795 1.31 11
844 0 11 0.92 1.795 1.26 11
844 0 10 0.94 1.026 0.72 22
844 0 8 0.94 5.384 3.79 97
1813 0 24 0.96 4.615 6.97 100
3344 8 30 0.14 4.615 12.86 94
4938 38 16 0.92 7.692 31.65 100
5094 38 7 0.96 14.871 63.13 100
2906 37 -4 1 13.076 31.67 100
2125 37 -5 1 11.025 19.52 100
2875 36 -2 1 12.564 30.1 100
3688 36 1 0.98 13.589 41.76 100
4375 39 1 0.98 14.871 54.22 100
4906 39 0 0.96 15.384 62.89 100
5219 38 1 0.96 15.64 68.02 100
5406 38 -1 0.96 15.64 70.46 100
5625 38 1 0.94 15.897 74.52 90
6000 38 10 0.73 2.051 10.26 10
5188 17 35 0.86 7.436 32.15 100
4563 14 13 0.96 11.794 44.85 100
3781 15 10 0.96 12.564 39.59 100
4000 14 12 0.94 13.076 43.59 100
4406 14 12 0.96 13.333 48.95 100
4594 13 11 0.94 14.102 53.99 100
4875 13 11 0.94 14.102 57.29 100
5188 12 11 0.94 14.358 62.07 100
5344 12 12 0.94 14.358 63.94 100
5594 11 14 0.94 14.358 66.93 100
5750 11 15 0.94 14.358 68.8 100
5938 11 17 0.94 14.102 69.78 100
6063 10 17 0.94 14.102 71.25 100
6281 10 17 0.94 13.846 72.47 100
6375 10 16 0.92 13.589 72.19 100
6469 11 15 0.92 13.589 73.26 100
6594 11 14 0.92 13.333 73.26 100
6781 11 15 0.92 5.128 28.98 11
6250 3 43 0.73 2.82 14.69 58
5719 0 27 0.92 10.769 51.32 100
4531 0 17 0.92 14.102 53.25 100
4750 0 17 0.94 13.076 51.76 100
4875 0 18 0.94 13.076 53.12 100
5094 0 18 0.94 13.333 56.6 100
5188 1 17 0.94 13.333 57.64 100
5344 0 19 0.94 13.333 59.38 100
5438 0 20 0.92 13.333 60.42 100
5563 0 21 0.94 13.333 61.81 100
5656 0 21 0.92 13.333 62.84 100
5719 0 22 0.92 13.333 63.54 100
5813 0 22 0.92 13.076 63.34 100
5969 0 23 0.94 13.333 66.32 100
6000 0 23 0.92 13.333 66.67 100
6125 0 23 0.92 13.333 68.05 100
6156 0 23 0.92 13.589 69.71 100
6219 0 22 0.92 13.333 69.1 100
6406 0 21 0.92 13.589 72.54 100
6281 0 21 0.92 13.589 71.13 100
6469 0 22 0.92 13.589 73.26 100
6531 0 21 0.92 13.589 73.96 100
6594 1 21 0.92 13.589 74.67 100
6688 1 21 0.92 13.589 75.74 100
6688 0 21 0.92 13.333 74.31 100
6781 0 19 0.92 13.589 76.79 100
6875 0 19 0.92 13.333 76.39 100
6813 0 17 0.92 13.333 75.7 55
6500 0 45 0.71 2.564 13.89 11
6000 0 27 0.86 9.743 48.72 100
5219 11 16 0.92 14.871 64.68 100
5188 11 15 0.92 14.102 60.97 100
5250 10 16 0.92 13.589 59.45 100
5313 10 18 0.92 13.333 59.03 100
5313 9 18 0.92 13.589 60.17 100
5406 9 22 0.96 5.641 25.41 10
5406 0 44 0.71 2.564 11.55 11

 

[andol469]

You're getting a lot of knock in the lower gears. I may be reading it wrong b/c it's 2:30 AM here and I keep confusing the knock #s and the timing #s I would first try to tune for 0 knock, just to give you a nice, safe tune for now.

The RPMs seem to drop a little low in 2nd gear. Also looks like you're shifting at about 6000 rpm... your 16g should be able to hold boost at least to redline, I would think (I've never run a 16g.)

What was your 60' on that run? Why did you set the base timing to 2*?

If I can find it, I'll post a log from one of my high 14 low 15 runs.

Sorry if I'm reading the logs wrong, like I said, it's 2:30am But the above advice is where I would start.

 

[Taboo]

Why did you set the base timing to 2*?

Because he had to :dunno: . With all the extra fuel, he had to go so low on the S-AFC that his timing went through the roof (and produce heavy knock and consequent timing pull).

 

[diambo4life]

You definitely need an AFPR!! I bet your airflow values at WOT were in the 1200-1300HZ region, maybe even less.:dunno:

 

[TransAmConvert]

My airflow values werent quite that low, more like 1500-1600.

What i cant figure out is why 1st gear looks like such garbage, second isnt much better, but third is textbook.

I only set it to 2* because I was advised to by a couple friends, im not dead set on that by any means. Those timing values are corrected for the 2* base timing.

I know she's on the cusp of breaking a 13, because the mods are there and the motor is good, but it's still so far away

Also, I apologize for the log. I couldn't figure out how to space the columns out.

 

[diambo4life]

My airflow values werent quite that low, more like 1500-1600.

That's still low. I forgot you had a stock 2G MAS and not a hacked 1G MAS.

You are running too rich.:dunno: Just to give you a rough perspective. When I used to run my 14B last year at 17-18psi with FIC 650cc's, 255lph pump and a hacked 1G MAS, I had the AFC at almost -30 across. This was on 110 gas. My airflow values were very very low and I had very high timing. I didn't have an AFPR though either but my car was still trapping 103 consistently although it was very obvious from my logs that the high timing was killing my top end.

 

[TransAmConvert]

Im tuning her for pump gas, as its not really a race track car.

I know i have to take some more fuel out, and im going to try to do it with the AFC a little more. I think my best option is going to be to try and drop the fuel pressure to keep those airflow values up a bit.

 

[diambo4life]

Start tuning at a lower boost level. Say 15psi and work your way up. You won't believe how dropping the fuel pressure will help.