I have a 2020 XLT 4x4 crew cab 5.0 with 3.31 gears. Truck is bone stock. I'm having an issue with consistency at the drag strip. It's not uncommon to have a swing of 7 tenths of a second from quickest to slowest passes in a day. I make it a point to keep everything I do consistent.

Every pass I shut off the advance trac, switch driving mode to sport, drive around the waterbox, get the truck straight then shift to 4 HI. I leave from an idle and let the trans shift itself. Coolant temp is always between 190 and 200 and trans temp is between 180 and 190.

The MPH is always between 95 and 96 MPH. ETs swing between 14.30s and 14.90s. This make racing successfully a pain. Forced to sandbag during eliminations to have any chance of going rounds.


Anyone else having this kind of inconsistent performance? What did you do to improve it? I see guys on youtube making passes that are fairly consistent but all those trucks have at least a tune. Would prefer to do something that wouldnt cost as much. Pull a fuse, etc. Any tips?

 

What are your 60 ft time differences when you run a 14.30 and 14.90?

 

60ft. 2.161. 2.113
330 6.274. 6.053
1/8. 9.607. 9.252
Mph. 74.04. 77.16
1000. 12.469. 12.004
1/4. 14.876. 14.326
Mph. 93.71. 96.78

I guess I was off a bit on the mph difference. Didnt have my slips in front of me.

 

Very difficult to say without data logs. Being a 5.0 the factory logic sends the blade wide open at full throttle, unlike ecoboost. Without any more data, my best guess is that false knock got it in the slower runs. Sometimes when knock retard hits early in the run, like on the launch, the slow advance rate is activated and you don’t get your timing back for the entire run. The 5.0 can be pretty bad about this and sometimes I’ve had to limit knock retard at low rpm to limit the effects.

 

Is this something that could be either eliminated or decreased with a tune?

 

Do you use the same octane fuel all the time?

 

It can be tuned to fix that but most tuners won’t for various reasons. I wouldn’t trust them anyway. The first thing would be to confirm that’s the issue through logging. Then you’d have to identify the mapped point, load, and speed where it’s happening. If you’re wanting to run low octane sometimes, you’d reduce the borderline table at that load/speed/mapped point, then reduce the knock retard limit by that same amount at the same load and speed. If you run 93 all the time then you could probably leave the borderline table alone or even add a little to it.

Switching from global to per cyl might also help if it isn’t like that already.

 

Launch off idle with the auto hold or whatever it's called engaged. I tested this to knock off at least 2 10th off the 0-60 time consistently when my truck was stock. I would datalog. These trucks heat soak when idled for awhile which is likely to happen in the lanes before running. It can induce knock What gas are you running again?

 

to keep times & operating temps consistent... even when stock wouldn't a high cfm blower plugged into a suitcase type generator quell the heat soak? Well if the lanes are typical T&T capacity. Roughly 15-30 mins between runs??
Ive seen a few street guys with a full electric tow rigs/rolling podium tool stands so the vehicle can be moved in the lanes w/o starting.

 

Running E85.

Went racing yesterday and kept the temps lower, engine in the 180s and trans in the 160s. Still wasn't consistent but on had a swing of 4 tenths as opposed to 7. Haven't done any data logging yet. On the good side it did run a new personal best. 14.04 at 99mph