Timing numbers to shoot for on blown 5.3
 

Hey guys I'm going to a dyno day this weekend and want to try to tweak my tune for my TVS 1900 powered 5.3. I'm just trying to take advantage of this dyno time while it's strapped down. My AFR at WOT averages 11.5 and timing is right at 16 or so. I'm wanting to load a different tune between the 3 runs so that I can see which makes the most power, so I need to make 2 additional tunes before hand. I will also log each run to keep an eye on KR.

What would be a good number to shoot for, 19ish? This is on 93 octane, no meth.

Also what about AIT table, mine starts pulling timing at 113°F and I'm usually at about 135° at the end of a run here in south Louisiana. Can I adjust this or leave well enough alone?

Air Per Cyl Grams/Cylinder {link: E38.APCYL_DMA}
IAT °F 0.88
-40 4.000000
-31 4.000000
-22 4.000000
-13 4.000000
-4 4.000000
5 4.000000
14 4.000000
23 2.000000
32 2.000000
41 2.000000
50 1.000000
59 0.000000
68 0.000000
77 0.000000
86 0.000000
95 0.000000
104 0.000000
113 -1.500000
122 -2.500000
131 -3.500000
140 -4.500000
149 -5.500000
158 -6.500000
167 -7.000000
176 -7.500000
185 -7.500000
194 -8.000000
203 -8.500000
212 -8.500000
221 -8.500000
230 -8.500000
239 -8.500000
248 -8.500000

Thanks guys.

How much boost? I set IAT timing pull above what you would normally see and what you have tuned for... Kinda hard to do it in a rush like you are trying to do - you really need to add a little at a time till it levels off on power/torque, then drop back to the last value that gave you an increase. Also, you may very well need a different amount of timing to maximize torque than what you need to maximize power - i.e. you don't generally end up with XX degrees across the RPM/boost range...

Yeah, I realize this isn't the proper way to optimize the tune. The truck runs good for what it is at 5psi, just wanted to see if I could make a little bit more power with the 3.7 pulley. I need to get these heavy ass tires off this thing, I'm sure that'll make a huge difference as it sits right now...I got pulled by an 02 camaro on the interstate lol.

What size tires you running?

I'd pulley down, a custom spec cam, and add some meth to keep the iat down. What exhaust are you running? At 5psi I'd imagine 19* would do well. I ran 20* in my fbo procharged 6.0 with 91 and meth. Did really good. Didn't mess something up till I tuned the spark down to 13*. Lol

I've got 33x13.5" tires, they weigh in at 76lbs a piece!! They are just about worn out so I'm going to go back to a 275/70/18 or similar sized tire...I really want to upgrade to factory 20s but don't have the cash for that right now.

Lol that blows, why'd you turn the timing down so much? My ultimate plan for this truck is a fully built trans, headers, cam, meth, 12psi, just not sure I wanna go down that road with it being my DD haha. One day it'll have 500 to the ground, I've got a few buddies with pesky coal burners that I wanna demolish ;)

With 5#, I would make one pull with what you have in it - add 2* for the second pull - and add 2* more for the last pull... see how much it picks up with each pull and post back - post dyno graphs if you can...

I turned it down by the recommendations on here. I was aiming for 16*. Went altitude more than planned

That was the plan, 2* then another 2* on the 3rd run and keep an eye on KR. I'm sure the engine will be heatsoaked on the 3rd run so the IAT table will pull some of the timing anyway. I could talk tunes and theory all day I'm obsessed with this stuff lol.

Well we had a good time at the dyno today, had a few modded cobras put down over 750+ swingit. It was a pretty full schedule and I didn't have time to change tunes between runs, I only ran the baseline tune which should have been about 16* of timing. The truck made 330 to the wheels @5psi unlocked in 2nd gear with the bigger tires, and from the looks of the plot I could increase my shift rpm a couple hundred rpm for sure, the power never peaked before redline at 5800 rpm. Too bad they couldn't plot rpm vs hp and torque. My previous dyno numbers were 250 with stock tires and tune only, so I'm pretty happy with the results.

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