Went and did an after STS dyno run today and above 5000 rpm my A/F climbs from 11.9 at 5000 to 13.5 at 6000. That was at 9 psi with methanol. It made 347hp at 5400 and 369 ft-lbs at 4700. I am sure the 22" wheels didn't help the numbers either. I also still have the stock injectors. The turbo is a GT-35.
Since I don't have a scanner I will hand type in the dyno chart
first column is rpm, second HP, third TQ, fourth Air/Fuel

4000 268.4 352.4 12.5
4100 270.4 346.4 11.9
4200 278.1 347.7 11.3
4300 287.6 351.2 10.6
4400 297.6 355.2 10.1
4500 308.2 359.7 10.2
4600 317.8 362.9 10.6
4700 330.2 369.0 11.0
4800 330.3 361.5 11.4
4900 339.2 363.3 11.6
5000 340.4 357.6 11.9
5100 341.8 352.0 12.1
5200 342.8 345.9 12.4
5300 343.5 340.4 12.6
5400 346.6 337.1 12.9
5500 335.5 320.3 13.1
5600 329.7 309.3 13.3
5700 318.2 293.2 13.4
5800 293.1 265.4 13.4
5900 296.7 264.1 13.4
6000 310.4 271.7 13.4
6100 308.9 265.9 13.6

 

you are gonna blow that thing up...on a dynojet with that heavy truck...get it at 10.0-11.1 and you SHOULD be good on the street

 

I have never tuned an forced induction car higher then 11.5:1 at WOT.
You should taper it off (richer) as you reach WOT for engine longevity/safety sakes.

Get some new injectors, and a better fuel pump!!!!

 

stock injectors will never work. Get some 40lb+ injectors. I might now of a set that will be avalible soon.

 

damn...what they said for shure.....

 

Did your fuel pressure drop off at all? Did it increase with boost? Either way 13.x:1 is dangerous. Also with meth I've heard you need to keep the AFR even richer due to the signal the burnt meth sends the o2 sensor.

 

How do you monitor fuel pressure? Does the Diablosport Predator have that value on it? I think I see injectors and a walbro pump in my very near future. When I look at my Predator doing WOT runs my O2 milivolts are all 900-940 at 6 psi and 880-920 at 9psi with no knock retard at all. I know the factory 02's aren't that accurate by with me getting no knock retard I thought I was ok. Also since my wastegate vents to atmosphere I am losing that exhaust out before the tailpipe where they are sensing the air fuel, would that cause it to look lean?

 

12.5 is pretty high for a FI motor, anything above that is Boom time. I was running at 12.5 on 9#s boost @5600rpm and destroyed #7 piston a couple of week ago. Get it re-tuned and stay below 12 all the way. Some even say 11.5 to 11.7, that is where I plan on keeping mine when I get the new motor in.

 

I think I know what your problem is. When your meth. comes on its telling your o2's your running really rich so it backs off your fuel supply. Your o2 will read 900mv but meth reads alot higher than fuel so your cpu thanks your at the right a fuel ratio while your really running way lean. The only way to get it tuned right is to use a wideband or at the dyno. Oh yeah you also need some 42 lb. injectors

 

Even at 6psi with no methanol it still reached 13.2 A/F. Guess I will buy some injectors and get it tuned next payday. My local dyno shop quoted me 600-700 to dyno tune it with either LS1 edit or HP tuner. Is this a ok price? I already have it modified with a predator tune, will I have to return it to stock before they start using LS1 edit? I guess my Predator will turn into an overpriced code reader.