giiventofly

iTrader: (8)

I have a 3800 stall speed converter with a 2.1str. At 25 mph (3.42s & 26in. tires) the converter is slipping 834rpms. This is through HPTuners, engine speed vs. input shaft speed. As the engine rpms go up it gets gradually tighter untill it's only slipping 275rpms right before the shift.

track times are consistently slow, but I didn't lose any mph. Trying to figure out what the issue is before I start spraying with the converter... I fear that will just make magnify my problems, especially if I am pushing through it n/a.

performabuilt

iTrader: (25)

The converter will always slip bellow stall and the further below the stall RPM the more it will. It will also slip some even at stall and above and the higher the STR the more its likley to slip. At a 1,69 str we have noted above stall the efficency aproaches 96 percent but will be lower "more slip" with a higher str.
Spraying you will in effect increase the torque and HP of the engine and therefore increase the stall flash and yes you will get more "slip" All of this is normal with a high stall converter.
No converter is 100% efficent even the stock converter never reachs a perfect 1 to 1 thus the reason for lockup to improve fuel efficency by eliminating the slip.
If your not getting the times you want your converter stall and str choice may not be ideal for your set up. What do your 60ft times look like? What times are your running ? Whats your rear ratio?

giiventofly

iTrader: (8)

3.42 gears, 255 mickey thompson drag radials, and 2.0 60' foots. Best its done n/a since the converter went in was 14.9 @90 on a 2.0 60 foot. I didn't really gain anything from the stall, I've been trying to get the 60 down lower but it seems like no matter what I change it stays consistent. great bracket racer, very slow though.

performabuilt

iTrader: (25)

Are you spinning in the 60ft?

giiventofly

iTrader: (8)

nope, tires hold good.

performabuilt

iTrader: (25)

I dont know then, You can get a harder kick in the bottom with a higher STR but on the flip side you will have more slip accross the board. A lower STR wont give you as good a 60ft but will reduce the slip and be more efficent.

giiventofly

iTrader: (8)

Yeah, I've been pretty perplexed. I've gone 3 different days now, changed how I leave, tire pressure, pulled the front sway bar and no matter what it wants to run a 14.9 or 15.0 all night. I might just try it with my nitrous and see what happens, if my times don't improve there I'll probably pull it out.