Drag racing with L/U??

[1chance]

I was just wanting to know, i have a L/U converter, and i put a switch on it to cut it on, and off. When im racing do i cut it on before i launch the car, or cut it on after i get going. Do i run it at all when im racing? Will it kill trans sooner?

 

[Boost231]

you will want to lock the converter in 3rd gear. now where in third is what you will have to find out what works best for you. some 85 some 95 just play with it and see what your car likes

 

[1chance]

Thx, so dont launch with it! I was thinking the chip would do that, but im not sure if it does, it's a TT chip.

 

[jpratt]

I have launched with it on. A lot safer looking for the switch and flipping it before stagging than at 90 MPH and accelerating like a bat outta the hot place.

 

[GNVYUS 1]

Do it via the TT chip, so you might need to send it back to Eric to update it for 85mph lock up.

 

[Grumpy]

it may not work locking it up on the line .. when ya hit 2nd it may drag the car down to much . We do it in third .. really depends what your puttin out for power

 

[Sweet6]

My car likes 70 MPH. But like others said you need to see what your car likes.

 

[TurboDave]

Locking it on the line will definately cause issues, as mentioned. The extreme bog when it locks as second gear hits among other things.

That and the fact that if you're running a single disc converter, you wont be doing WOT lock ups for very long, maybe one racing season, before start seeing extreme degridation in the clutch performance.

The only way to do WOT lockups and still have a converter live for many years is a multi disc unit ($$$$$).

 

[Sweet6]

Locking it on the line will definately cause issues, as mentioned. The extreme bog when it locks as second gear hits among other things.

That and the fact that if you're running a single disc converter, you wont be doing WOT lock ups for very long, maybe one racing season, before start seeing extreme degridation in the clutch performance.

The only way to do WOT lockups and still have a converter live for many years is a multi disc unit ($$$$$).

X2 You probably will not see much of a gain with a single disc Vig. The 5 disc is the way to go if you want to lock at WOT. I get about 1.5 tenths and 4-5 MPH locking the 5 discs at 70 MPH. I am not sure how other brands LUs work. But I have had great luck with the 5 disc.

 

[TurboDave]

X2 You probably will not see much of a gain with a single disc Vig. The 5 disc is the way to go if you want to lock at WOT. I get about 1.5 tenths and 4-5 MPH locking the 5 discs at 70 MPH. I am not sure how other brands LUs work. But I have had great luck with the 5 disc.

Imagine how much better a 7 disc would be. Wanna trade?

 

[Sweet6]

I had a 7 disc. it locked up on me. But my new 5 disc has less than 1% slip when locked. if it ain't broke don't fix it. :biggrin:

 

[300kGN]

I'm running similar stall and switch to L/U after the burnout. There is some bog when I hit second but the time slips are best when its locked from 2nd on. Try it any way you want, see what works for you. I know mine doesn't pull as hard unlocked due to a lack of top end HP

 

[wickedtt]

I have launched with it on. A lot safer looking for the switch and flipping it before stagging than at 90 MPH and accelerating like a bat outta the hot place.

Do you have any billet parts in the tranny? Do you need them or will it hold up for a while locking the converter at wot?

 

[jpratt]

Do you have any billet parts in the tranny? Do you need them or will it hold up for a while locking the converter at wot?

My tranny is full roller and lots of billet stuff.

 

[Grumpy]

I had a 7 disc. it locked up on me.

I had 4 or 5 of them here that did the same thing and to think.. Precision told me nobody else was having problems with them I do know 3 in the 9s (V8 cars) that have the 3 disc and they work fine locking them up on the line

 

[Sweet6]

Precision told my trans guy they never saw one lock up like mine.

 

[Grumpy]

Precision told my trans guy they never saw one lock up like mine.

hahahaha.. matter of fact I still have one here.. has less than 300 miles on it one of these days its goin back and goin with a 3 clutch.. throwing it in the Mazda and see how it works .

 

[TurboDave]

Precision told my trans guy they never saw one lock up like mine.

Thankfully mine hasen't yet after almost 8 years of abuse!! (fingers crossed)
It does have one annoying habit. When cold, and shifting from Park/Neutral into a gear it kills the engine. A little feathering on the throttle solves that though.
I'd love to get into one of their 3 or 5 disc models, but budgets being what they are and all, I'm stuck with what I have.

Can't complain about it's performance otherwise though. Got tired of replacing my stocker every season. This one's held up now for 8+ years and still is as perfect as the day it was new (except for the above mentioned quirk).

 

[Sweet6]

My 7 disc lasted about 6 years maybe 6,000 miles. My new 5 disc is great. No rattles and very rarely stalls when I put it in gear cold. I paid $375 for the new 5 disc with the broken 7 disc trade in. So it was not that bad of a deal.

 

[Lee Thompson]

remember

A torque convertor can not multiply torque when locked. IMO, locking @ the top of 3rd--5800 in my case yields the best results. I seem to remember that @ the top of 3rd is easier on parts.