Smokinstorm

iTrader: (5)

I'm looking for some real world numbers here from those that have locked their converter up during a pass at the track. I have a manual switch so I have the capability of locking my converter (Yank PT4000) up anytime I want. I've also been to the dyno and verified that locked my car puts down 15 more horsepower than unlocked. I've just picked up my car with a newly rebuilt transmission (one more time ) and am looking to better the times in my sig now that I've got a fully functional transmission. My butt-dyno tells me that locking up the converter at about 90 or so MPH gives a nice little increase in acceleration. Not dramatic but definitely noticeable. Any less MPH in drive and the converter pulls the motor down well off the horsepower peak. Has anyone actually tried locking their converter at some point during a pass and recorded a better time/MPH because of it? Am I just hoping for something that isn't there? Let me know your experiences with this if you don't mind. Thanks.

Coach 02 A3 Z/28

iTrader: (10)

I would try locking it and go. Then I would make another pass unlocked. See if there is any change. Good luck.

Coach

Pro Stock John

iTrader: (34)

A few of us used to run the Vig 3600 aka the #7 pump converter, and that was pretty loose.

I liked mine and the runs went like this (2000):
11.75@112, 1.57
11.76@114, 1.58 (locked it 3rd gear)

When the converter is big, you can end up having a lot of slippage in 3rd gear. So you can try locking it up. I thought we concluded it was hard on the transmission though.

IllusionalTA

iTrader: (9)

it's gonna be really hard on the lockup clutch as well.. Most HP converter's sacrifice the size for less weight,etc.. So the lockup clutches are usually not as beefy.. I know i wouldn't wanna lockup a TCS at WOT.. Oh wait.. It does that on it's own anyway.. lol.. You can give it a shot.. but doubt the gain's are going to be as beneficial for a n/a car like it would be for a Turbo car such as a GN, they do it all the time...

AFTICA

iTrader: (8)

I tried it with my little Vig and got nothing...same ET & MPH. Haven't tried it with the Yank SS4000 yet.

Smokinstorm

iTrader: (5)

I'm thinking it'll be more beneficial with a larger stall converter as well as compared to a 3400-3600 converter and especially a 2800 one. My shift extension is around 5500-5600 so the converter is slipping pretty good right after a shift. I know this works with a turbo motor with unlimited torque but I'm not so sure about a stock N/A motor with low horsepower and torque like I have. Also, I must admit that it doesn't really do the lockup mechanism any favors but in the search for better times, I'm willing to give it a go. I'm going to try to find the point at which the locked vs unlocked horsepower curves cross to maximize my gains. I've talked to a few people and their opinion was that the MPH may go up a tad but the ET would remain pretty much the same.


This is the plan Coach. I'll definitely post back my results. I'm actually going to try several passes to see at what MPH I maximize my gains (if any). I tried locking it up last year in the 1/8th mile but it was too early and bogged down the motor and actually slowed me down. My plan is to try locking it right at or just past the 1/8th mile mark. Like I mentioned, my butt dyno tells me anything before 90 MPH pulls down the RPM too far. I'll try it at 90, then 95, then 100, etc to see if it's doing anything. Now I just gotta find a 1/4 mile track that I can run at this weekend. 1/8th mile tracks are everywhere. 1/4 mile ones aren't. Weather this weekend is supposed to be around 70 which is a far cry from the <40 degree weather I ran in last Fall when the tranny died so I can't really compare now to then. Maybe I can still stay in the 7.40's at the 660' though from having the transmission actually make the 2-3 shift without hitting the rev limiter. Results to follow.

Smokinstorm

iTrader: (5)

Well, the results are in but far from conclusive. I didn't get enough clean runs in to say for sure but if you judge whether locking the converter helps by how much the car picks up out the end then I'd have to say it helps. I got in one decent pass not locking the converter and the car picked up 22.08 out the end. Two passes when I locked it the car picked up 23.27 and 23.28 out the end. It also ran more MPH at the 1320' on the locked passes at 111.31 and 111.82 respectively vs 110.96 on the unlocked pass. So you see it ran better but not 100% conclusive data here. I need to calculate the DA at the track but it had to be horrible. My car was down a couple tenths and MPH at the 1/8th compared to how I was running last time out and that was with a transmission that wouldn't make the 2-3 shift. Of course tonight the temp was around 70, it was just about to rain so the humidity was way up there and the barometric pressure had just about bottomed out. My car wouldn't even run an 11 in that air but in all fairness I never got an error free pass. Long Winter. Gotta get back in the swing of things again. I'll try again later but this is the data I got so I posted it up as promised.

edit: I calculated the DA at 1124' vs -1524' the last time out at my local 1/8th mile track. You reckon that explains why my car was so slow vs last time out?

sleeperstyle

iTrader: (4)

i've been thinking about trying this with the spray- i'd program it to lockup in the middle of 3rd gear (about 110mph or so) with hptuners and see what happens.

i DO have a 5-disk multi clutch converter from tci however, it was a prototype when kevin windstead built it about a year ago. maybe that is something you could look into for extra insurance, and if yank doesn't offer it i know tci will build one for you.

nick y (twin turbo c5, 9.9 @ 145mph) is running the same prototype verter' as me, just a lower stall speed. he locks it up somewhere in 3rd gear and i believe has had no problems with it yet.

Smokinstorm

iTrader: (5)

I really believe that FI or N20 cars with torque to spare benefit from this a lot more than NA cars. Good luck sleeperstyle and let everyone know how it works out for you. Eventually we'll get a good database for everyone to compare their combos against.

aram

iTrader: (7)

I wanted to try locking my TCI 4000 to attempt to stay in 1:1 in the 1/4 but I just don't know if it'll last unless I send the converter back to get the clutch beefed up.

ssracer8

iTrader: (5)

I'm bringing this thread back to see if anyone has additional input on locking converters. Please feel free to post up your results if you have done this.

Thanks

Reboot

iTrader: (5)

I gain about 3.5 MPH around .05 in the 1/4 when locking my Rossler TH350 lockup tranny and Circle D multi disk lockup verter on the big end (133.6 mph unlocked and 137.1 mph locked). The car also goes through the traps 800 RPM lower locked up.

That being said I'm in the process of swapping to a TH400 with a Chance 5000 stall hoping to get more out of the first 1/8th mile. I'm swapping trannys because the TH350 has a lockup input shaft and having a race converter made for it is a bitch. The 5 disk converter weighs 42lbs vs. 23lbs for the Chance....We will find out soon if my times improve. I'm guessing my trap speed won't.

Captain InsaneO

iTrader: (38)

I have a vig 3 disk that I lock up in 3rd gear at 100 mph. I think you gain more MPH than ET. I was told this would be the case by the guys at RPM transmissions. I don't think you will gain much on a NA car. In theory it's suppose to help lower trans. temps. I don't know if it really matters when you run 1320 feet.

Randy WS6

iTrader: (69)

Are you guys locking your converters before you shift in a higher gear or right after ?

XS HP

I have the same converter and spoke with yank about this multiple times. They told me that locking the converter will NOT reduce et (with the pt4000 and for NA applications at least)

kline454

iTrader: (1)

my car picked up 3mph and dropped .1 on et. locking the converter on spray but the converter only lasted 40 passes that way before i burn the lock-up clutch up. was running tci super street fighter running mid tens on 200 shot.

daniel6718

iTrader: (36)

dont lock it right as you go into 3rd...it will bog down...honetly ive seen gains of half a second and 7-9 mph locking one in the top of first before the 1-2 shift...

Bersaglieri

iTrader: (13)

Us diesel guys lock them at the track all the time, if we didn't the trucks would run at least a second slower. If my single disk converter can hold 1300 ft/lbs of TQ in a 7500lb truck a single disk Vig should hold 600 ft/lbs in a 3400lb car. Although they recommend multidisk converters for locked shifts. Only problem we've run into its snapping shafts in the trans and it's also rough on splined hard parts. Input shafts in a 47RE are necessary for locked shifts, not sure about 4L60 and 4L80's. I'll let you guys know after next season.

-Dustin-

JFM-jr

iTrader: (23)

Maybe a vendor will poke his head in here but from all I have read engauging the lockup clutch at WOT is VERY hard on that disc. Most converters (other than a multi disc) simply do not posses the square inches of plate surface needed to hold any power. These clutches are not designed to operate at WOT.



I'm interested in the setup on this car. I would think that converter was broken to achieve those results in a typical high stalled F body like ours.

daniel6718

iTrader: (36)

1slowformula on here in his bolt on car picked up noticeable gains...locking it in 1st...converter isnt as much of a worry for me as the trans it breaks trans parts easily