To transmission or not ?

[projet1]

I am looking for some opinions ! I am using a T53-L-1 in a full size pick up truck. Can't decide if I should use a transmission for two forward gearz, or just go one to one with a reverser. I'm an old school piston guy and used to having two or three forward gear selections.
Would appriciate any insite !
My progress is on www.t53ss.com
THANKS

[turbochris]

My nimbus powered van hauls ass with direct drive. I'm geared for about 130 mph tops, you're gearing it higher and a low gear may help with your setup. Personally I would go with a powerglide driven directly off N2 without a converter. I would have huge ass wheel brakes and a huge ass N2 brake. if you drive on the street you'll be driving into the brakes all the time to make up for spool time. You absolutely have to drive the hydraulic pump for the trans off N1 so it spins all the time. Trying to use a converter and the pump built into the trans will just result in fried converters and clutches.

A pro mod powerglide builder is a good friend, I'll help you set it all up if you want. We've been planning something like this for a while and have some great inexpensive ideas for external transmission pumps.

Use the stock clutch pedal to work the N2 brake and you can use both feet if you need to haul it down fast.

The reverser you plan on using, is it a lenco? You could always stack a few underdrives behind it if you feel the need for some gears down the road. Will the reverser you plan on using have a neutral? it's not that important if you have no neutral. This would not require an external pump like a glide but it could be expensive.

Also, consider a way to lock it down. I would put microlocks on all hydraulic brake lines, if anything happens, hit the microlock, stomp all the brake pedals hard and get the hell out. With a free turbine, you really cant just throw it in neutral if it gets away unless you don't mind an overspeed.

Powerglide w no converter, N1 driven trans pump, huge N2 brake right in the bellhousing activated by the clutch pedal, huge wheel brakes- do this and you'll get a woody every time you get in the thing.

Maybe if you get that N2 brake big enough, you could use it to launch like a transbrake.

The old turbine Granatelli vette had a TH400.... no converter, pump driven off N1. Worked perfect and he was in your horsepower range.

Don't even think of starting it without wheelie bars!

call if you need help!

Chris

[turbochris]

C'Mon guys, John? Anders? This guy wants opinions. Tell him I'm close or tell me I'm full of shit! I don't care! I just need to see this pickup run! This man called me a few days ago, he had this project on the shelf to redo his workshop. Now its back to the project!

[Johansson]

This kind of engineering is way above my head so I´ll just keep my piehole shut and assume that you just unloaded a huge pile of bullshit on the poor guy. =)

No seriously, that sounded like a good way of doing it.

[turbochris]

I usually unload before I get on the forums, right after the morning coffee. Have to have a clear head with all this technology....

[projet1]

Well guys.. What I have found is that a reverser will not disengage with a load on it. So if I'm on a hill or incline, and the N2 is dead stopped. I won't be able to get it in to neutral or reverse. So this means that I will have to have some way to disconnect the N2 from the reverser. I have found a Lenco coupler that the drag boat guys use I'm told. It would give me a way to un-couple when shifting.
Doin more research !
STAY TUNED

[turbochris]

if you're on a hill just give it a little power, when you move forward a little hit the free turbine brake and it will unload.

[ernie wrenn]

Your talking about a whirl-away. It is the same sprag setup that is used in lenco type transmissions. As long as power is applied they will stay locked in, only when input power is removed will they free wheel.

This was originally designed to keep the Nitro motors being pulled down during shutoff. BIG BOOM! Been there seen it...

We are going to set up a Walther 601 to a double under drive Bruno/lenco with reverser and a Carlile reverse direction gear box with quick change gear assembly.

ernie

[turbochris]

either way, no manual gearbox will co-operate while there's a load on it. Try to pull a standard trans out of gear while the power is applied, not happening, you burn the shift fork up before you move the slider. Now just yank N2 down with a nice N2 brake and that will unload everything nicely.

This is the issue- use a transmission that requires "unloading" to shift, or use a trans that's designed to change gears while loaded, like a powerglide or TH400. Keep in mind we're talking about the ability to go from neutral to forward to reverse in a reasonable manner, having more than one forward gear is really a moot point as it boils down to if you can go from first to second or neutral to reverse or anything with the trans torque loaded. If we use a trans that requires "unloading" to operate, there's 2 ways to unload it. 1 is to put a clutch in the system, 2 is an N2 brake. While it may not seem clear, the N2 brake can solve all the problems. While a clutch may seem like a simple solution, all I can say is the last thing you want to do is "let go" of a free turbine. Most free turbines have a governor but they're pretty much scheduled to control a free turbine with a known mass attached to the output shaft. Using a clutch on the output shaft will reduce that mass with the push of a clutch pedal.

A properly built automatic transmission could negate the need for an N2 brake by simply making the forward clutch engagement really smooth. Put it in gear, N2 drops down smoothly and you're good to go.

I never understood why trans builders make a trans go into gear hard. Shifting hard under load is a good thing but going into gear from neutral at idle, do we really need to chirp the tires? ha ha their shift kit is shimming the pressure regulator with stacks of nickels!

[projet1]

Well I guess my concern is the RPM that the N2 will go down to at idle. I was told the T53 will still exert a considerable amount of torque even when at ground idle. So if the powerglide is a good pick, I would think that an N2 brake is still needed so you can pull the N2 down before shifting to drive or reverse.
I understand the issue with "unloading" the N2 under power. Guess I look at it as you wouldn't push in the clutch in a stick car while your foot is to the floor on the gas. Seems like when on the turbine, same thing is gonna be true!
Having some issue finding a brake rotor that can spin 6600 rpm (max rpm on the T53) for the N2 brake also ... Hmmmmm
NOT giving up ! Thanks every one !

[projet1]

A local trans guy asked ? If you use the powerglide, and shift from drive to neutral under power (which could happen .. high gear and neutral are next to each other) ..... wouldn't that be the same as pushing in the clutch ? Same damage could happen either way ?

[turbochris]

Mark Nye used a front brake rotor off a bike, you'll need something w more mass. I'm sure any quality rotor will be fine at 6600. Just look at those huge cast flywheels they put behind small block chevys and they take the rpm. About shifting into neutral under power- Now your in the right mindset, don't unload the turbine! Use a neutral lockout on your shifter. We may be able to modify the N2 governor to pull the fuel out faster near 100% N2. We're not trying to regulate rotor head speed and we could tighten up the fuel schedule, this would make it more effective/safer in a lost load situation. You're doing great, just a few more dots to connect!