parish8

iTrader: (6)

this is a 2nd gear start, i was told you can tell what the stall is somehow with a 2nd gear start. the rpms dont really move much all the way up to 40mph.

what is the rated "stall"? thanks!

samz28

could be the car is shifting gears, stall feels like the new honda battery operator hybrid with a CVT (or a audi a4) cept less efficient. I've driven both (laff) with CVT trannies' and thats how my tci SSF 3500 feels like, its shifting alright if you can hear over the headers,etc but the rpms drone at one spot until the lockup kicks in (programming) then rpm's drop considerably.

I wish they would just lock up the converter at low load points like 5-25% TPS then it would be a bit less loose

Colonel

Parish, I think you may have misunderstood something I was referring too.

Remember I said that stall speed can only be measured with the output shaft of the converter at 0 RPM and at WOT? The problem is, when you go to WOT in 1st gear, your brakes are not strong enough to keep the tires from spinning (and thus, the output shaft of the converter is no longer at 0 RPM.)

Some vehicles, like the '00 and newer F-bodys, allow you to start off in 2nd gear without the tranny downshifting into 1st gear even at WOT if you put the gear selector in 2nd gear. I don't know if your truck does this or not. If it does, you should be able to go to WOT without the tires spinning (and thus the output shaft of the converter will be at 0 RPM.) And if so, a simple observation of the tach, or better yet, a monitoring with a diagnostic scanner like Autotap, will tell the tale.

parish8

iTrader: (6)

i may have missunderstood part of what you said, this was a 2nd gear start. are you saying i should mash it but not let off on the brake and hold the truck from moving at all? i can do that too.

Colonel

Correct. Go to wide open throttle and do not allow the truck to move if at all possible (and it should be if you are truly able to stay in 2nd gear.) Look down at your tach and see where the RPMs level off. Don't worry, it won't hurt anything to do this for a few seconds. That's not time enough to build up excessive heat.

Colonel

...And ONLY do this with the expectation that the truck is going to leap forward. In other words, don't blame me if you go crashing through your garage wall!

parish8

iTrader: (6)

lol, ok, ok. i will go some where safe but i dont think i will have any problem holding it back. it took off like a yugo on 2 cylinders when i did that other test.

Colonel

I'll be curious to see what it does.

parish8

iTrader: (6)

ok Colonel, got a new chart for you, i am not sure why the mph shows me moving but i didn't move at all. truck was in 4wd and it didn't even try and move. i can get my mph to move even in park if i rev it high enuff, my last truck was like that too.


what is the stall on this converter?

sleepersilverado

iTrader: (1)

parish i believe you are correct that they missed it with this one.

Ragtop 99

iTrader: (7)

I hate trying to read these damn graphs, but it looks like over 4000 rpm if I got my colors right

Colonel

I don't trust that chart. It's telling me that you were stalling 4700 and we KNOW that's not the case, elsewise you'd have an SE of about 6000! And it's telling me that you're moving 7-10 MPH when we know that you were going ZERO. Forget the chart...

Question...when you were at WOT and the RPMs leveled out (with the tires not turning of course) what did your tach say??? There's your answer.

XLR8NSS

iTrader: (4)

Colonel - I think that 4700 reading was spraying a 150 shot with the brake on. Parish8 is a little bit crazy. N/A it was around 4000rpm according to another graph that was posted in the truck section.

https://ls1tech.com/forums/showthread.php?t=130391

parish8

iTrader: (6)

over 4500, i watched the tach. the chart showing mph is not a problem with the scan tool, i would guess it is a problem with the speed sensor. every NBS chevy i have had would read some mph(on the dash) if you reved it high in park, wouldn't suprize me if the auto equiped cars did the same thing.

lets just assume the tach is right, any ideas what would cause something like this. anything in the tranny? anything in the stall? i talked to yank today and he told me the same thing, that there is something wrong with the numbers.

i would think if the tach signal i am using was wrong it would be wrong for both cases. not high for one test and low for the other. the tranny seems tight, shifts real nice. i have had more than one sliping tranny so i kind of have a feel for that.

is there any way i have a set up that is just that much diferent than what is normal that no one knows for sure how the stall will act and that they just missed the mark. i hear you and yank both saying the comeback rpm is 1000 over stall. could it be that it is diferent for a 4l80? or diferent for a 4800lb vehicle? just tosing out some ideas here.

Black Blown 02

My truck is 4800lbs, and with the SS3800, My stall is 4000, and my shift extension is 5000. So its probably not the weight. 1st and 2nd are closer together on the 4l80e than the 60e though. Thats pretty weird.

Colonel

Parish, were you spraying or NA when you witnessed 4500 on the tach at WOT with the truck sitting still?

parish8

iTrader: (6)

4500 with a 125shot
4000 NA

Colonel

That's high. Something isn't right and it's either the tranny, converter, or the tach.