Tar Heel

Our nitrous is blowing through the converter and/or causing the transmission to slip. When I take the transmission out to have it done I need to put a tighter nitrous converter in. I called Circle D and they sell a very nice multi-disc converter that they think will work good both NA and on spray. He suggested having a toggle switch in the car that locks the converter up in each gear for when I run it on nitrous. That sounds like the best of both worlds, and would keep from having to load a NA and nitrous tune, but how in the world do you wire that? I've never heard of such a thing. Anyone have first hand experience with this?

Scott

Rob Petyo

I have a converter lock up button in my 98 also, when I tried it, all it did was lock and then unlock the converter, must have been too many passes on it for it to lock and stayed locked. Since then I've replaced the converter with a power adder series (Yank PA 3,800) that is made to take a hit of N20. If I ever drop a 200 on it, I'll post results on how it reacts.

I occasionally use the lock up button on the street (cruising) if I'm right at the rpm place where it locks/unlocks

smokinstorm

I had a converter lockup switch installed in my 2000 Camaro SS H/C/I car and locked the car put down 483 to the tires vs 459 unlocked. Locking it at the track gained right at 2 MPH in a 1/4 mile but precious little ET. I was running a PT4000 Yank converter. I did it as a performance mod, not a mod to keep it from blowing through the converter. I wanted to do the same thing on my Vette that's making double the power but Yank, RPM transmssions and Mayhem Motorsports all talked me out of it. They said to just get the right converter and let it do what it's supposed to. I've had multiple opportunities to put the lockup switch in but have resisted the temptation deferring to the experts on this. But I think I have the right converter so I don't need to mess with locking it up. PY3600 Yank. RPM Level VII 4l60e.

Tar Heel

Thank you gentlemen. Dave at Yank said for a relatively small fee he will take our SS 4000 and tighten it to a 3400 (PA IIRC) and that should solve our issues. It was the guy I talked to at Circle D that tried to talk me into a lockup switch.

Just for fun and my own knowledge I'd be curious how such a switch would be wired.

Scott

smokinstorm

I had the local transmission shop install it in my Camaro. He just grounded the lockup solenoid according to what he told me. He put it on a toggle switch which I put in the center console beside the shifter. In that low of a horsepower car, 25 was enough that you could feel. I plotted the horsepower curves both locked and unlocked by MPH and saw where the curves crossed. I locked the converter at that MPH. In the Camaro, on all the passes unlocked the whole pass I never trapped over 124 in the 1/4 mile. Locking the conveter at 102 MPH I believe is where the crossover point was, it never trapped less than 124 and hit 126.00 one time. It was like a miniature progressive shot of N2O.

Chris Stewart

You can make a manual lockup switch like this: switch to ground, red connector on the pcm in pin 42. Location is behind the passenger side front tire. It's a neat trick to have.

C5 Pete

This guy Chris is a pretty fart smucker... he's got all kinds of cool tricks.

smokinstorm

Do you do this in your car during a pass? You've got another relatively big horsepower car that I was told wouldn't make that big of a difference on so I didn't do it on our Vette. It's right about a 25 horsepower peak to peak difference but you only have that extra power a few seconds and it's not 25 extra the whole time it's locked. It just builds to that difference at the top of the RPM band. When I listen to cars going down the track, I hear a few locking the converter in Drive so I know it's still happening in some cars. I haven't plotted locked vs unlocked in the Vette but let's say the horsepower curves cross where they did in my Camaro at 102 MPH. The Vette hits 102 MPH about 4.3-4.5 seconds into the run somewhere around 400-450' out. That would give us another 4.5 second to accelerate with a little more power on average out he end. Just can't help wonder if that wouldn't add another MPH or so to the trap speed like in the Camaro. Maybe it's just me but saying you trapped 160.03 (over 160) sure sounds a lot cooler than saying you trapped 159.68 (almost 160). Forgive me it that sounds stupid.

Edit: I just watched a pass from inside your car in your vid and you definitely locked it about halfway down. What difference does that make in your car?

Chris Stewart

I don't use it much. With a multi disk converter that is capable of holding it, I was curious to make a pass with it. Threw the switch after getting into 3rd. It locked about 120mph, the result was 9.5@150 where I usually trapped 146. I'm not sure what happens if you force lockup in 2nd and then WOT shift into 3rd, never done it.

It has gearing advantages if needed, dropping about 1000rpm for me on the big end. The main reason I added the switch was after taking a drive in the mountains. Limited to 30mph and steep incline, my 3600 stall was never locked and making a ton of heat that cooked my trans. I'll be ready if we do that again.

A couple funny things with it, you have to remember to deactivate it when slowing down, or it bogs the motor just before you stop. Also if I test it cruising around, the regular lockup function completely quits until I restart the vehicle, but can still manually control it.

smokinstorm

Wow, that's a huge gain. I wish I'd asked this of you before putting my car back together when I was having all those transmission/converter issues. I'd love to pick up 3-4 MPH. Or even 1. I'm not sure a supercharged engine like I have will pick up like you did as your TT setup has mega torque vs what I have and will throw you forward like being hit from behind with a semi truck when you lock the converter. I tried locking it in 2nd gear in my Camaro but the car fell on its face on the 2-3 shift. Again, this was a small cubic inch N/A motor though. If the car was geared to only go through 2 gears in an 1/8th mile, I'm sure locking it would have shown gains.