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The "Project"

FABRICATOR

Well-Known Member
Are you using the trans to power hydraulics for the rear so called axle.

Just a guess, I think I read somewhere that your trans was putting out alot of pressure. Plus that would explain why theres not a shifter.

I have seen something similar on a street sweeper. It connects directly to the ring and pinion. I have thought about this for a rock crawler to eliminate driveshafts, but didn't think I could get the speed needed.

Enjoyed the read.
Sorry for the delay, and thanks. I’ve been reflecting over the question, not ignoring it. Hydraulic drives have much to offer and could be in the future, but there are many design obstacles to overcome for dezert racing. In every sense of the word, this race car has a transaxle. I can only get into some of what makes it work, some of what it can do, and some of what it doesn’t have. IMHO, a transaxle can be the ‘seed crystal’ to the design of the entire rest of the car.





There is a shifter for this transaxle. It's just not where you would normally find it, and it can be operated with your hands on the wheel. Except for the torque converter, the power flow path from the crankshaft to the rear tires is all mechanical. There is no new or weird science involved; all of it is well proven in large numbers and brutal environments around the world. The whole thing is as basic and overkill as the steering shaft a few posts back, and likewise, built to take B1K’s in stride. It uses some GM Hydra-Matic ‘Turbo-400’ type internals and a torque converter drive. It has no shift forks, shafts, dogs, detents, synchronizers, or drums. There is no clutch, pedal, or linkage. Gear housing stress is low to moderate during even the harshest shifts or vehicle landings, and you can do what ever your heart desires in reverse gear. The very robust A356-T6 aluminum casting was done by Astro Foundry (now defunct) in Burbank, CA, makers of head/cylinder units for full-size aircraft engines. The molds are still around. The oversized 4340/300m shafts and high-nickel gears were produced by an East Coast maker of racing transmissions. Weight wise, the unit is a beast, but it is competitively compact.





Like any dezert racing transaxle, this one too is a singular mechanical unit that bolts directly to the engine, with no V-drive, no U-joints, and no inter-section shafts or couplings. There is nothing to align, clock, grease, vibrate, bind, fall apart, or adjust. It cannot strip or break a ring and pinion the way other transaxles do. This unit is specifically designed for high reversing torque loads, high reliability, optimized physical dimensions, and very minimal maintenance. There is a valve body, of sorts, so shifting is carried out through a simple push-pull cable. Shifting is naturally sequential, takes virtually zero time even under full throttle, and can be upgraded to occur automatically. There are 2 separate filtered and cooled lube oil circuits. One runs through a water/oil heat exchanger, the other through an air/oil cooler. Allison (GM) style residual pressure valves at the returns keep the cooling circuits full at all times. There is a closable line pressure fluid accumulator for the clutch application circuits. Unlike most race cars, which have indirect cooling of some or all gear sections; all gearing in this transaxle is cooled by circulating, direct-contact lube oil.









The final drive employs no stress multipliers such as a spool, solidly coupled back-to-back CV joints, bevel spider gears, roller clutches, tooth count ratios greater than 4:1, or other problematic methods. Every effort was made to avoid having any gears that go out of mesh, slide on shafts, or have excessively high contact pressure. The differential is a full-blown, straight-cut, planetary gear system similar to F1 racing. It is bulldozer simple and reliable, with no squiggly gears, and no side or end thrusts of any kind. The differential unit and all rotating parts run on oversized anti-friction bearings. Other than the torque converter and tires, there are no friction-driven traction devices of any kind. Though not anticipated necessary, there is a driver controlled positive differential lock. Drive ratios are changeable and currently range from 2.72:1 to 5.42 to 1. The design final ratio is a comparatively high (low numerical) ratio of 3.91 to 1. The gearing will work well with the high torque engine, low-stall converter, and low vehicle weight.





IMHO, the simple and straightforward design of this transaxle was, and still is, capable of providing unparalleled performance in the areas of power capacity, reliability, longevity, and packaging. It will do this with comparatively high efficiency, and low costs. In this application, it will help give the driver better than average control of rear bite, good fuel mileage, unmatched cruise capability, and very easy operation. It will provide any top speed the driver wants for any length of time. The throttle is to be a major player in performance and handling of this truck. 4,500 RPM is ~125 MPH.
 

FABRICATOR

Well-Known Member

I thought I would post up my idea of an engine for a TT, especially this one :). It’s nothing exotic; in fact, it’s just the opposite and very simple. It’s a venerable Mark IV Big-Block Chevrolet, with a displacement of 496 cubic inches (8.1L). (It has nothing to do with the later, long-stroke GEN VII 496). This engine is built to provide a true meaning of flat torque curve, strong throttle response from just above idle, and be able to run for hundreds of race hours. The displacement may seem big compared to present TT's, but in reality, the others are disproportionately undersized. In mild tune, the engine puts this truck at under 6.5 LB/HP and 8.5 LB/CI. With a responsive yet progressive intake system and a very low-stall torque converter, there is to be no waiting for things to spool up and grab while going for a holeshot, exiting a turn, or any other situation. Traction is by throttle, now. The engine is mid-mounted, which makes it continuously favorable to ride, traction, handling, and the laying out of other components. Despite its size, there really are no compromises to vehicle performance, weight, balance, packaging, efficiency, or cost. Unlike forward placed big-blocks, this one doles no brutality to the suspension. Though the engine is strongly and thoroughly mounted within the chassis, there is no structure added for it. As for fuel consumption and drive train stress; peak torque won’t much exceed that of the top, pro-built TT small-blocks. The effective RPM operating range will be wider and at least 1,000 RPM lower. There is no need for any driveline segment to be under-driven or over-driven.







With ~10.5:1 compression, the engine can run on good pump gas. In comparison to the big displacement small-blocks found in most TT’s, the larger 4.440 bore (by 4.00 stroke) not only makes room for larger valves, but provides a major unshrouding of them as well. The better breathing is further enhanced by the RAT motor’s splayed valve design. Cylinder heads are AFR 305cc “as cast” with CNC’d chambers. But even these humble stump pullers, by just .500” lift, will outflow most any small-block style head at any lift. The relatively mild cam timing, valve lift, and RPM, along with some other simplifications, significantly raise reliability, raise longevity, and lower costs. An innovative but simple off-shore wet-sump oil system, and high volume marine type pump and aluminum oil pan, are used to greatly reduce clutter around the chassis, raise reliability, and again, lower costs. This is not a Chevelle or Silverado engine begging for nice treatment and lots of luck. It is 100% from *companies like World Products, AFR, Callies, Childs & Albert, Crower, JE, Jesel, ARP, etc. (*Not endorsements and may change at any time!) It also is not just 50 to 80 cubic inches more of the same overextended thing. This unit is capable of generating an honest and reliable 500 ft/lbs torque by ~2,000 RPM, and 600+ ft/lbs torque from ~3,100 to 6,700 RPM. With shifting pretty much when ever you get to it, and revs limited to ~7,000 RPM, the driver’s attention can be focused elsewhere and opportunity for error minimized.





A 1:1 belt driven high volume/high pressure water pump, front mounted radiator, dual thermostats, and oversized high-mounted purge tank, make up a cooling system that is much like that of a big-rig truck. A pair of contorted, but otherwise typical 2” equal length headers, make up the exhaust. The latest plan… called for a multi-port, long runner EFI, with a progressive opening 2-shaft, 2-barrel 1,000cfm throttle-body. Also in the plan is a short detachable "snorkel" to quietly bring in (did someone say ram?) cooler, cleaner air from just above the cab roof, or perhaps, from openings in the leading edge of the large roof/wing, with air flowing back within the wing. From there, air feeds to a neatly tucked away, very long range, centrifugal truck type air cleaner. The block, heads, intake, motor plates, oil pan, water pump, valve covers, and timing cover, are aluminum. The Advance Marine valve covers trim some overall width even while stretching over shaft rockers, but make her look like a dang BBF. The engine is like your typical Trophy-Truck unit but with some extra strength, an easier life, and a never-ending blast of nitrous at lower RPM’s.:) I don’t know of any other type of gasoline engine that can provide as much usable power, reliability, or longevity. Regardless of the budget, point standing, or seriousness; if it didn't over heat, run low on oil, or breath lots of dust, it won’t need a tear down after every race. Approximate cost NEW w/basic EFI system: ~$20k. Minimal prep & pump gas: priceless :)

 

FABRICATOR

Well-Known Member
The Fuel Cell is nothing special, but it does hold more fuel than most and sits where few TT’s have them sit (except the PPI Toyota). Its capacity is ~79 gallons after the foam, and it sits directly on the floor near the middle of the chassis. This all helps to provide good range, low polar moment of inertia, and low center of gravity. Helping to push that CG as low as possible is a cell footprint on the floor of roughly 1,122 square inches. No part of the cell resides under or between the seats. Though it is strongly and thoroughly supported, there is no structure added for the cell. Unlike the PPI Toyota’s center mounted cell, this one is not a structural part of the chassis. Regardless of the fuel level, its mid-mounted location is continuously favorable to ride, handling, and the layout of other components.

The firewall forward of cell is aluminum. The firewall, engine and exhaust shielding aft of the cell, are all stainless or other robust, higher temperature metal. Fuel inlets include a dry-break on one side of the cab, and a 3” cap on the other. To avoid a fueling disaster, or splashing fuel where it shouldn't go, each fill is located in a large capacity all-metal spillway that directs misplaced product to the ground. To reduce clutter and improve safety, there is a triple in-tank pump arrangement, each with its own power source. The design is similar to the one pictured but is ‘militarized’. The assembly fits into a fuel maze/trap arrangement and is surrounded by a fine-screen pre-filter. It uses an OEM style, 2-step return system. Pump power is disabled if the cell is other than right side up.

The cell may seem oversized for such a light vehicle, but it fit in with no significant compromise to safety, performance, weight, balance, packaging, maintenance, or cost. It adds flexibility to when and where you fuel, which is something that can win or loose races. When combined with comparatively low vehicle weight, a drive train with exceptional cruise capability, a low stall torque converter, and EFI; fuel range is expected to be ~300 race miles.
 

Dumfast

Well-Known Member
Very cool!..Thanks for the new info..What does that motor weigh?..Would a 572 be a good choice also?
 

scottm

Well-Known Member
Wow, nice. That trans is awesome. How does the power turn 90° without a ring and pinion? 45° bevel gears? I like your engine philosophy, especially the wet sump. How often have you seen a ds engine lose the belt and grenade? With some drainback enhancements, a good pan with some custom baffling, and an accusump accumulator, my oil pressure warning light has never once flashed, and that includes a million flights over the 100+ foot tabletop at speedworld.
 

FABRICATOR

Well-Known Member
Thank you, sir. Look forward to more.
You are welcome. I'll see what I can dig up.

Very cool!..Thanks for the new info..What does that motor weigh?..Would a 572 be a good choice also?
Serious race blocks and heavy duty heads keep the weight savings from being anything spectacular, so the overall savings is only about 200 pounds less than an all iron BBC. I haven't ever weighed it but I'm sure it tops 500 pounds with the oil system. There are limitless size and gearing combinations that could work. If you build a BBC for torque (unbuild?) and tailor the drive train to use that torque, there is more than enough power available even from a 427 inch setup. The breathing is that much better. IMHO, when you go much over 500 cubic inches with 10.5:1 or higher compression, the torque will become more difficult to use and more likely to cause damage. A small block would move this car faster than any other car, the BBC is just to save money. :)

Wow, nice. That trans is awesome. How does the power turn 90° without a ring and pinion? 45° bevel gears? I like your engine philosophy, especially the wet sump. How often have you seen a ds engine lose the belt and grenade? With some drainback enhancements, a good pan with some custom baffling, and an accusump accumulator, my oil pressure warning light has never once flashed, and that includes a million flights over the 100+ foot tabletop at speedworld.
Thank you. I can't discuss specifics, and not saying it's the same thing, but there is another transaxle/differential on this forum that does not use an R&P for the final reduction. Good to hear on your oil system. This one is nothing complex and very reliable.
 
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Dumfast

Well-Known Member
Is the wheelbase 125" or is it longer?....Is it SCORE legal with the bigger tubing requirements?
 

FABRICATOR

Well-Known Member
Is the wheelbase 125" or is it longer?....Is it SCORE legal with the bigger tubing requirements?
That's a good question. I haven't really kept up with every rule change. However, I do know that it can beat the 4k threshold by using a small block and a couple other 'omissions'. So unless something has changed again, the answer would be, 'it depends'. The wheelbase is 125".
 

FABRICATOR

Well-Known Member

Devin J

Well-Known Member
Why are all you guys swinging from his nuts? I don't get it?
Do you really have to act out like that? What's the point?

My reason for the "swinging" is, I'm interested about the project, and I want to see more of it. If someone shows interest in someone else's work, it could be seen as motivation for the guy doing the work.

Kinda like if someone built a duece and a half, and did all sorts of things to make it better, isn't it nice to hear "hey, great job! let's see some more!"......
 
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