Automatic Transmissions

[ggl205]

Well, Tom Burkland finally convinced me an automatic just ain?t the way to go. Even though the engine should be capable of pulling all six gears, the drop in RPM between shifts slows the turbo and requires it to spool up again between gears. There are ways to keep boost up between shifts but my engine management system does not have that kind of control. We have enough trouble with traction at Bonneville but to add additional wheel spin when boost comes up after every gear change, is not going in the right direction.

So, I stay with my current set up until a good used Liberty Extreme air shifted 5-speed comes along at an affordable price. That desire alone may keep me in ?G? class the rest of my life.

John

[racergeo]

   Back in 02 I started my Bonneville adventure. Built my car with a lot of compromises. SB2 NASCAR engine with all of the parts sourced from EBay. The engine has different heads on each bank, 6 cracks in the clock, a cam selected by price and a half a dozen other compromises. It made 515 wheel HP. I selected a powerglide 2 speed for cost and simplicity, no torque convertor. I ran as fast as 274mph and have a red hat. The car that beat my record a few years later used a NASCAR engine builder back east to build a similar engine to 850 crankshaft HP and has a Liberty 5 speed. It beat my record by less then 2mph. I set my record on one of the worse tracks in memory.

  My point is simply this, If you are going to take advice that is aimed at putting you at the pinnacle of land speed perfection, then I will tell you right now a Liberty 5 speed is going to have you come up short!!!! Craig Liberty himself told me that the fast TUNER cars are using 7-7-7 yes 7 speeds in the 1/8th mile. When a couple of them heard he was building a 10 speed for George Poteet they immediately ordered one. You know as well as I that a 2JZ that makes only a thousand HP is a week suck.  My advise is simple, boost your engine up a hun or two more so you can pull some more gear. Watch the YouTube video's of the in car recordings of Rick Yacoucci  shifting his 260 c.i. SB chevy that has a C4 Ford that uses a 3500 stall torque convertor. Oh and that's on his 400+mph run on gasoline. I have no idea what this saying means, "buts there is more then one way to skin a cat" 

[desotoman]

John,

Not meaning to hijack your thread really. But the fastest wheel driven car does not have a transmission and drives off the line without a push truck.  Listen to Tom Burkland.

Tom G.

[racergeo]

   Rather then race because you don't have big money???

[ggl205]

I am one of the founding member of make a dime look like a dollar. It has to be this way or I don?t race. My current circumstance in unblown G classes is good but will be limited once the engine goes back to its owner. Could be a year or more but don?t really know for sure. So, I use what I have and I have this 2JZ.

My question about Rick?s liner is what is he using for a transmission and rear end? He indeed drives off the line, something I would like to accomplish but have yet to find the answer. I would speculate Rick is using an automatic transmission but which one? My 2JZ can easily support more than 1000 hp but the car has to prove it can handle that much before moving up boost pressure. My aero is not nearly as good as Rick?s but his is a streamliner and mine a lakester. I will say, for a lakester, I have a decent Cd, good enough to achieve a theoretical 325 mph with far less than 1000 hp, at least according to tunnel data.

Burkland has a mountain of experience at Bonneville. He has helped several lakesters achieve speeds substantially over 300 mph and ultimately, that is something I would like to achieve. But to do so has to be affordable and practical. Honestly, these clutchless 5-speed gearboxes like Liberty and G-force have one flaw and that is a deal breaker. They can slip out of gear if you pedal the engine. So, here we are, still no solid solution for a compact drive away drivetrain that works with big horsepower. Any suggestions? I will listen.

John

[racergeo]

  Oops, rather then not race Lots of 2JZs run auto transmissions and a couple companies make adapters. Transmissions and converters are readably available. If it doesn't pan out many street rodders and bracket racers will buy the most popular trans. the turbo 400. Just like a nitro engine likes a load against it also a turbo spools faster under load. I was serious about bumping the boost up to make up for any extra loss thru the trans. as many 2JZs make in excess of 1500hp and some that run in the 6's at over 200mph near 2000. This response is in regard to you stating that the cost of the Liberty would keep you in G class for the rest of your life. Another thing to consider is, an auto with a converter absorbs much of the shock load on the gear change. A dog type box is instantaneous and shocks the heck out of the drive train. A clutch that can cost $2-3 k or more will cushion that, but there is little room for error. A turbo 400 is a totally proven deal and won't cost you a small fortune in trial and error. That's it, I'm out of pennies O.K. you posted will I was writing this. Rick is using a Ford C4 auto and a 3500 converter.DO IT LOL

[ggl205]

racergeo:

In the beginning, I enlist every idea regardless of cost to implement. At this stage, a different drivetrain for my lakester is investigatory so cost doesn't enter the picture except where it is obviously too expensive. I have run several different automatic transmission simulations to see if any would work. So far, only the 8L90E 8-speed from a C6 or C7 Corvette seems to work but only when I start in third gear. RPM drops look like something I can live with but just barely. I don't know how Rick manages to make the C4 trans work given severe RPM drops between gears. He would have the same problem of loosing turbo boost after each shift. Question is, is this really a problem or is he able to retain boost sufficient to continue acceleration without interruption?

I like the 8L90E C7 Corvette automatic over others because it comes with an attached posi diff and a 2.41 R&P ratio. Price for a complete, reasonably low mile gearbox can be had for between $1200-$2000.

John

[desotoman]

John,

I don't know if this will help you or not. When I was running the roadster I had a Kilgore turbo 350 that had a close ratio gear set in it. I bought a new motor for the car and called Kilgore and asked him if there was anything I needed to do to the transmission as I was now going to go from a 6000 rpm limit to a 9500 RPM red line. He advised me not to use that transmission at those high RPM's as the stock mainshaft would not last at those RPM's.

I believe that the Waters Roadster runs a blown F motor and they use a turbo 400 in it. It has run in the 260 plus range. Kilgore makes close ratio's for the turbo 400 along with other parts. Kilgore has been involved in landspeed racing for many years and a good guy.

Tom G.

[ggl205]

Tom, roots type blowers should work fine in front of an automatic trans. It are the turbos that apparently suffer if the engine has to make up too many RPM?s between gear changes.

I will give Kilgore a call and see what he thinks can be done.

John

[mc2032]

Download of a run on the turbo Sportster.  40 or 50 millisecond shift kill (airshifted) at gear change.  This really shows the drop in boost pressures.  1st, 2nd and 3rd gears last just seconds then a long pull in 4th to the 3 mile.  The five speed engine is in the works to reduce the gear ratio changes between shifts hopefully carrying more rpms into the next gear.

[desotoman]

John,

I could be wrong, but I am pretty sure they run a turbo for supercharging on that F motor in the roadster.

Someone please correct me if I am wrong.

Tom G.

[ggl205]

Tom G., that would be encouraging if Waters did use a turbo on that F motor.

John

[ggl205]

Come to think of it, Waters does use a turbo on his F motor. On a 2JZ, no less! Gotta talk to these guys.

John

[kiwi belly tank]

2Jz's aren't a peaky engine with a tight power band like your N/A 2 liter. The fastest 1/4 mile guys are running 400's & glides on them. If you fall off the turbo with a 4 speed to 300+ you did something wrong. There's so much off the shelf stuff for 2J's just like the LS you have to try pretty hard to screw it up!
  Sid.

[ggl205]

?There's so much off the shelf stuff for 2J's just like the LS you have to try pretty hard to screw it up!?

Sid, if there is anybody who could screw it up, it is me.

John