Blown06

iTrader: (32)

Well it turned out to be a shitty day.
I ran twice...
Run 1: 12.96 @ 110, 2.234 60'
Run 2: 12.95 @ 111, 2.221 60'

Granted it was very hot (track temp was 141*), I still don't understand why my truck has absolutely zero power below 5000 rpm.

I data logged with HPTuners and it showed that I launched at 2350 rpm's each time. Thats as much as the converter will let me get, I had it floored waiting to take off. I had absolutely zero tire spin, even with the stupid track temps. My cousin video taped it from the starting line and the truck just sort of rolls off the line like a stocker until about 100 feet out and then it starts pulling pretty good. I don't understand if it is something in my tune or is my motor that weak down low. After looking around on here there are guys with mild N/A set-ups 60 footing better even with stock converters. I'm lost right now, and a little discouraged.

Second problem, I got like 6* of KR in second gear and for a reason I can't find. My IAT's were around 80* and it has never knocked before. Maybe the knock sensors need to be desensitized somemore. ???

I'll start a thread in the tuning section and post my tune and scan. I'm going to call Allen Nelson tomorrow and see what he has to say, but I'll bet you guys can offer some words of wisdom as well.

trever1t

iTrader: (14)

Interesting. Your 60's are where I was NA but your trap speed is better than best run's of 109.5 Seems like you are sriously making up for lost time at the top.

Blown06

iTrader: (32)

Hell, it ran 115 mph about two and a half months ago in San Antonio in very similar weather. It pulls hard as **** once it gets over 5000 rpm.

ranwalk

iTrader: (1)

I believe its a combination of too tight of a converter and the 4L80E first gear. You need around a 3600 converter. I'm running a 3000 too at the moment and mine doesnt leave near as good as it should. The Procharger comes on stronger in the mid to top.
If you were spinning last time out and dead hooking this time that will explain some of the mph drop too. Now the knock, I dont know, get the tune checked.
Also, if this was different track, check with people that have been to it and others to compare. Some tracks net different times and mph for some reason.

ap2002

iTrader: (8)

this is exactly the first thing that came to mind..... with that 4L80e, I wouldnt be scared to go with a bigger converter to help you launch alot better...

hope you get it all squared away and go back and make a few runs.... weather sure isnt helping right now either...

ZO6Ted

Definitely get the tune checked, but you need alot more converter or the easiest thing is just add a shot to get it out of the hole and keep the one you've got for good street manners. For instance, had a '85 jimmy with a smog motor 350 that got a 1.80 60' with a stock converter and a 125 shot. Also, you may consider advancing your cam a few degrees.

Blown06

iTrader: (32)

Solution....

See Post https://www.performancetrucks.net/fo...63#post3715363

ranwalk

iTrader: (1)

The 3.73's explain alot too. I thought you had already switched to 4.10's. I dont know if I would do a transbrake, that rear end is going to grenade. You dont have to leave at 3800.....try flashing the converter and see how that works first.

ap2002

iTrader: (8)

I agree, mine flashes @ 3900-4000 with no transbrake and no problems..