TXsilverado

iTrader: (18)

here is my sheet. it's showing 3rd gear locked the entire run. it is also a motor pass on this sheet through 29" tires on 18" wheels (probably makes no difference) i am currently running a circle d 3,600 that was built for 4.10 gears, but i have switched to 4.30 gears.

race weight: 4,400 or so
4l60e and 4.30 gears
bogarts with 28x10.5x15 mickey t tires.

i have 2 stages of nitrous with as much as i can hook out of the hole, and plan to hit the rest as soon as 2nd gear hits. most likely 125 to 150 out of the hole...and im wanting to work my way up to a 250 shot in the end. looking at my sheet, i was thinking about 4,000 to 4500 which would probably work great for all motor, but i dont know exactly how to spec a converter for nitrous use. can any of you guru's make a recomendation, and explain why so i can learn. Thanks oh, i already have a 3 disk circle D that i plan to restall so i dont need a brand recomendation, just a size.

ryarbrough

iTrader: (18)

What does the converter flash to now on the motor? What size is the converter (diameter, not stall speed).

I'd say that 3600 is probably pretty close if you're going to spray it.... That's where mine is. It could probably stand to be a little looser, but not much.

dnkynrbk

iTrader: (34)

For one thing I think your gear is to low. You may need to go to a 3:73 or 3:90. Have you ran this car in the 1/4. I run a 28x10.5 and a 3;73 gear. I used to run a 4l60e. A i did try a 4:11 and I was bouncing off the limiter at the qtr.

Have you ran the car in the qtr?
What rpm are you crossing the line?
What does your cam spin to?

dnkynrbk

iTrader: (34)

Plus the more spray you throw at it the more you eat up the rpms.

TXsilverado

iTrader: (18)

not a car...it's a 4,400 lb extended cab silverado so the gear was based on that. on a 125 shot it trapped at 118 mph in texas heat...and im hoping with some of my recent mods and the bigger shot it will hit 126 which is my dyno peak. also, you can see where my cam pulls to in the dyno graph...maybe im not understanding your question correctly. peak is 6,400 and i shift at 6,800.

it's a 9.5" circle d tripple disk converter.

TXsilverado

iTrader: (18)

9.5. with the 4.10 gear it was flashing 3500 rpm dead hooking on motor. i havent sprayed this converter on the track yet. as i understand, going from the 4.10 to the 4.30 will actually lower my flash point a little due to it being easier to get the weight rolling.

ryarbrough

iTrader: (18)

Wow. Can't believe I missed the 4.30 thing... That does need to change if it's a 1/4 mile car... If you're only running the 1/8 it'll be fine. Still curious as to if you have any numbers on where the converter flashes on motor/nitrous now.

TXsilverado

iTrader: (18)

lol TRUCK! 4,500 LBS...this is not too much gear. im pushing roughly 1,000 more weight than you guys and have zero aerodynamics so my MPH is nowhere near as impressive as a light weight aerodynamic camaro.. im looking to trap 126 mph which is peak HP....i can go past peak just a little and make 130mph.

in my last post before i mentioned the flash points.

TRUCK!:

dnkynrbk

iTrader: (34)

I would spray it on that converter first and see where you are at before you pick another stall. Im curious to.

ryarbrough

iTrader: (18)

With that small 9.5" converter I'd be a little worried about it blowing through the converter when you spray the big shot. I'd bet it'll flash to 4200 or better now with the small shot. How efficient is the converter up top on the motor? I'd give it a shot as it sits and see how it leaves, and how efficient it is up top...

Good looking truck by the way!

TXsilverado

iTrader: (18)

it seems pretty efficient up top. it feels pretty damn tight to be honest. ive driven a ss3600 that feels WAY looser. i will be locking the converter on the dope so i guess it will be pretty damn efficient lol.

so even though my peak torque is at about 4800 i dont actually want it to flash there on the nitrous? thanks for the props on the truck. here is a better picture. thats just the first one i could find lol.

dnkynrbk

iTrader: (34)

Sweet truck man. Get some juice passes and let us know how it does.

ryarbrough

iTrader: (18)

My estimate was just a guess. There's no harm in giving it a shot and seeing what it does. Try and get a log of the pass so we can see what it's doing! If it were mine that's exactly what I'd do.

What does Circle D say about locking the converter up top? Where do you plan to lock it? I'm a little concerned about that...

TXsilverado

iTrader: (18)

circle d "dares you to break it"...i will probably lock it just past peak and let it run up to peak again.. most likely ill just lock it wherever it puts down the best times....or leave it unlocked if it does best that way.

Patrick G

iTrader: (14)

If you choose the right converter, you will leave it unlocked at WOT. Adding a triple disc lockup clutch adds unnecessary weight to the combo slowing your acceleration. Go with a 258mm single disc converter. The larger pump/turbine will have more holding capacity on the spray. Chris can fix you up on this.

ryarbrough

iTrader: (18)

Agreed... I'd be really nervous about locking the converter...

TXsilverado

iTrader: (18)

what about this scenario....im trying to be the first to launch consistant 1.5 60' times in a 2wd extended cab silverado. to do that i need converter and gears. i was thinking with my weight i could gear it down to get out of the hole quicker, then when i make it to peak rpm in 3rd, lock it and run it back up to peak again so i dont run out of mph....at the cost of a little extra weight from the 3 disk setup. im putting more into my 60' at this point than anything. once i get it nailed down, the rest of the run should fall into place.

ryarbrough

iTrader: (18)

That sounds like the logic from the old "variable stall" converters.

Doing that kind of thing is hard on lockup clutches. No matter how well they're built. Just makes me uneasy.

Patrick G

iTrader: (14)

You'll never gain the ET lost from the extra weight of the heavy triple clutches. Light weight and high efficiency rules with torque converters. Chris will hook you up. Just stay away from the triple clutches. You're putting yourself at a 1 tenth disadvantage that you'll never make up.