Posted in the auto trans section too, but may get better feed back here

Guys that drag race, do you leave your converter unlocked at the track? Or lock them out at higher speed? This is a cam only high stall car. Just seeing what some the 10 sec heads/cam and 10 sec cam only car seem to do. We get a new converter specd for the cam only setup in my wifes car and so far it seemed to have slowed down from last year when it went 10.90's@120-121 most of the time and went 6.95-7.05@96-97mph in good weather. First outing with the fresh trans and specd looser converter was 7.10@92 but the sixty foot was the same 1.44-1.45. Just wonder if it is hitting lock up or I need to look into the tune further, or if someone whats to look at a log

 

You can go into the tune and change the converter lock-up, even disable it looking at WOT.

What is your converter rated for? When they are on the loose side, locking it up in higher gear can net you some MPH and a bit of ET. Say you went with a 4600 Yank, it might like getting locked up somewhere in 3rd gear.

My 5th gen runs 2-3 more MPH locked up at the top of 3rd @99mph and keeping it locked as it stays in 4th (6L80E). We tested this quite a bit, locking it later didn't do much and locking it too early lugged the motor.

 

It a ultimate converter they specd out 4400-4600 I think. Where is in hp tuners? Or maybe the better question where should it be set too I guess to lock up at? It is a good running cam only car with a decent sized cam with a tighter converter last it was running 10.90's-11.00. Could the looser converter be going into lock up sooner causing it to slow down?

 

Lockup is typically based on rpm, not engine speed, so a loose or tight converter wouldn’t change when it locks up.

I’m not sure what tab in HPTuners is the lock up table. I’m not sure you can lock it up WOT, or in anything other than 1:1 gear or overdrive, but it has been too many years for me to remember correctly.

Good luck with your goals.

 

My old '98 Formula picked up over 2 MPH locked when heads/cam, and a little ET as well. The ET improvement would noticeable if you are running a big converter, because in high gear depending on your gearing and combo you might drive through the converter.

 

Ended up ordering a PT400 for it, the one in it was just little to tight and would only sixty foot 1.48-1.49 since we got it refreshed with the new stator. It ended up going 11.03@121 last weekend but only 1.48 60ft, its been a 1.42 before we got the new stator.

 

What trans in in the car, 4L60E?

If the converter company reccomends locking it, I would try 100MPH to start. Then try lower and see if it slows down or picks up. When it locks up it will drag the engine down a bit so you have to play with it.

 

It was staying unlocked and its a 4L60e, after I looked at a log I noticed her o2 voltage was zero on the two passes which caused her crappy Et and mph loss, which was from the o2 extension wiring being melted lol. We got it all fixed and went 11.03@121 at event 2 weeks ago but only 1.48-1.49 sixty foot, which is ok but I was hoping to get into the 1.38-1.42 sixty foot with it at 3280lbs cam only car, on a cold day in Nov it has been 10.85@122mph. I figured Id try a different converter to see if I can get more sixty out of it, maybe go 10.90's in the heat cam only.

 

How are you leaving with the PT4000 ?

Is the front end coming off the ground ? Might be able to play with the suspension and get that 60 dialed back in ?

 

Bad 02s, could run rich.

I'd run it unlocked and then try locked. Again could be worth I'd say half a tenth and 2-3 (maybe).

 

I have a Yank pt4000 in my car and it's a single disc converter ,I don't think they are supposed to be locked under power but you could call Yank and ask

 

I just ordered the yank, it wont be here for a month they said. Suspension works well everything on it is midwest chassis stuff, its been 1.42 before I had this ultimate converter refreshed.

 

Yeah you could call and ask Yank. They might think it's okay to lock since it's only for upper end of 3rd gear, and maybe your car is kinda light.

 

Yeah my wifes car is about 300lbs lighter then mine. I just figure with the sixty foot in the 1.38-1.42 range, it would be great with the car making 417hp to run 10.70's-10.8's. Its been 10.85@122 on a 1.42 before the converter was sent out for the refresh.

 

Might want to check the rear tires, they may be going away on you or the track prep isn't what it once was. As far as locking up the converter i know they will tell you NOT to lock it up as it will burn the lockup clutch out of it . The lockup in these converters is a single disk not ment to be locked up under full power . We went from a 3600 to a 4200 which put us at a 1.43 60ft but was way loose at top end going 10.82 @ 124 mph. with the stock 323 rearend . Have since ordered a TCI 4200 bolt together with the 3 disk lockup which is supposed to make the lockup usable under full throttle,and a 9"with a 4.30 gear. Should be interesting how this combination works out . Stock LS3 crate engine and a little suspension work .

 

Step 1, confirm with the manufacturer their stall is designed to be locked at WOT. I see people pick up MPH but not very often anything significant in terms of ET, so unless it's max effort is it worth the wear and tear?

 

Already fixed put a PT4000 in it, went 10.79@123mph with a 1.44 sixty then went 6.77@99 with a 1.41 sixty at our local 1/8th mile track, other converter was just too tight.