Xtrac huh, wow this truly is a best of the best build!

 

Drivetrain is Xtrac front diff which shuts off in corners and locks up under acceleration. Capable of handling 100% of power and torque up front.

Shaft is 300M

Tranny:
All six gears ratios changed and gears are the wider RSR square cut type.
All syncros are steel
Rifle drilled shafts for internal oiler for upper gears
All gears cryo treated and friction coated
Large external tranny cooler
Porsche RSR billet LSD
Tranny mounts delrin material
Tranny and LSD set up by Brian Copan

Clutch Tilton three disc with LFW.

Axles and CV joints custom and very light.

 

What about the viscous coupling? Will it have the ability to shuffle more power forward than the factory one?

 

It is almost as strong as the rear diff and has the ability to hook up almost 100% of the available power, however in all probability it won't be used for much more than 40% of available power.

It combines the best features of viscous, and ramp limited slip differentials, in one highly compact unit.

As well as offering speed and torque sensing characteristic, the unit is also fully adjustable. Torque sensing is carried out by a conventional symmetrical ramp arrangement with many options available. Speed sensing is achieved using a Visco-Lok shear pump unit. The Visco-Lok's unit is fitted with a valve that controls the speed at which the pump will start to lock the differential. This can be used to keep the differential open in cornering, but locking when a wheel spins up.

This unit offers the proven reliability of Xtrac's high quality components, combined with the unit's adjustability to give a truly competitive edge.

 

Amazing build! But a few questions. Besides the desire to build the ultimate p-car what is the intended use for this car going to be? Does it fit into any race classes? Will it be a driven on the street? Just curious. Thanks

 

KA will be responsibly enjoyed as a very limited use street car. A few DE's and AC's. Maybe some rallies and tours.

KA if raced would be in the open or unlimited class. Although she has plenty of power and an outstanding drivetrain and suspension, her weight of 3000 pounds would preclude her from being a serious contender on the track or strip.

 

Simon,

I can remember when I first ordered this car ....... for my wife. It took so long to get, she lost interest and bought something else. I had the car delivered to a tuner in Florida sight unseen. Took delivery six months later with 460 hp and didn't like it. It was then sent to TRG and eight months later got a 510 hp car. Although, it was near the top as far as turbo's went my AC Cobra was making more ..... a month later I sent it to S Car Go Racing where in late 2003 they were extracting about 650 rwhp and 620 rwt. S Car Go made some more changes and the car was tested by Dave Colman from Excellence. It cleaned house in an Autocross (TTD) and came very close to setting a record at Thunderhill for it's class. On a 104 degree day she went 11:40 in the quarter with a 60 foot time of 1.5 plus seconds. Soon after she bent all six rods and at the time of the Excellence article I set my sights on 1000 hp. At the time Gemballa had a car making about 800 hp. Needless to say our build was slow and others did hit the 1000 hp number. 1000 hp is fairly achievable now so I changed my goal to the most power the 996tt case would be capable of developing and stay in one piece.

Yes, along the way many things have been learned and shared. If it also wasn't for the efforts of others, we would not be where we are today. I can remember very well all the so called brick walls we hit and went through with the development of this motor..... boost, heads, cams, etc. etc.

I still find it amazing that it was only about ten years ago when the GT1 won LeMans with 600 hp. The giant CAN AM Porsche motors could make 1500 hp. Now we have exceeded both.

 

Interesting build up.. Some serious patience is needed for a 7 year build up.. WOW..

Mike

 

It's not the destination ........... it's the journey.

We are very close ..... in my way of thinking. Then again, others could probably build rebuild their motor in that amount of time. I am looking forward to having it by June 16th.

 

Mike,

I'm going to give you a honest answer as to why it took us so long. It came down to the rod stroke ratio. I wanted to run the largest stroke the case would physically handle. That's easy after a lot of mocking up ..... 82.4 mm. A person who wants to take the safe route would not go larger than 80.4 mm. Why ....... because the longest rod you can use after raising the wrist pin up in the piston as far as you can possibly go and reduce the wrist pin size by 1 mm (while engineering it to withstand the loads) will allow a 129.25 mm rod length. That is unless you go into the extreme costs of raising the deck height (along with it's assorted issues like the timing chain, etc.) Offset the wrist pin from center of the piston to true center and you gain another .50 mm for a virtual rod length of 129.75 mm. This renders a 1.575-1 rod to stroke ratio with the 82.4 mm crank. The 80.4 mm crank and the same size rods would render a ratio just over 1.6-1 which is safe.

These short rod motors can produce a hellacious bottom end torque, however any short rod ratio below 1.6-1 produces a rod angle that can drive the pistons through a liner and produces mountains of stress on the crank, rods, liners and pistons. This in turn required specially designed crank, rods, liners and pistons as well as an extremely efficient oil system.

As it was explained to me:

Longer rods give the pistons more "dwell," the brief periods of time the piston is at top dead center and bottom dead center. A longer dwell allows for better flow of intake and exhaust gases since the piston moves slower between up- and downstrokes.

Longer dwell also offers more time to fill the cylinders during the intake stroke and more time to scavenge during overlap. And since the piston hangs out at or near TDC longer, the combustion stroke has more time to deliver a thorough release of energy on to the piston.

In a stroked motor, the piston ultimately reaches greater speeds to cover the additional stroke. The speed makes intake, compression and exhaust strokes more turbulent and, consequently, more powerful. It also comes with its price in component wear, something to consider when looking into parts that increase stroke.

With a short stroke and a long rod, however, the piston accelerates more gently from TDC. It picks up its greatest speed further down the bore, at the point where the crank pin relative to the rod angle reaches 90 degrees. Since the pistons move from TDC slower, the entire bottom end absorbs less mechanical stress.

Even the short-stroke/long-rod combo has its limits. To accommodate extra rod length, some builders will move the piston pin higher into the slug, or opt for a deck plate. Either method requires an experienced wrench with access to a lot of custom parts.

Longer rods in a stroked motor can act to offset any increase in rod angle, but also requires a shorter piston. The deeper you dig into a piston to shorten it, the greater your odds of cutting into the oil ring groove and wreaking havoc with oil consumption. Most piston companies in the sport compact market engineer pistons with tighter ring packs and bridge rings to help avoid this problem.

Regardless of whether you take the stroker route or just run longer rods, you reach a point where you can no longer shorten a piston any further without compromising dependability.

Most engine builders believe longer rods are better, but a fringe of enthusiasts (like myself) still dig the low-rpm torque that shorter rods can make. Builders who want a ratio of less than 1.6:1 need to use the strongest aftermarket rods they can find, given the angle along with aftermarket sleeves to better fend off the lateral stress created by the rod angle.

Our tests were developing power and torque that was off the charts. We were afraid the case was going to come apart. This was the reason for ethanol and a pulsed CD system. Gas ignites with a big bang, ethanol needs a high voltage spark to ignite, however unlike gas it needs a pulsed ignition because it burns all the way down the bore. Presto, a fuel designed for a short rod stroker.

In addition, short rod strokers greatly benefit from a balanced/tuned plenum runner. Thus all the design and work with our very special system.

Thus, the reason for six years was a lot of stress load design followed by the custom manufacture of parts to our specs to bring out the best on a very special low rod length to stroke ratio motor.

 

Due to increase liner pressure and 105.4 mm bores the liners required a unique design incorporating a varying wall thickness and unique steel.

 

Update:

The research on the plenum is finished. There has been a silly amount of time and money thrown at this intake project. Tomorrow I will post a video which shows the differences discovered on different shapes/sizes of plenums (without visually showing the plenums) and how they effect response and power. The differences are very real.

For the time being I will not show pictures of the shapes because once seen certain people will pirate this work with knock offs. I know we don't know people like this.

When you see the proof of what has been discovered you will see these motors are on the edge of another nice leap in performance and power.

I was told I will have the video's tomorrow. As soon as I have them I will post.

 

Would you agree that when paying, for example, $900.00 for a plenum for a 911 is mostly for development and research and not the part itself and materials.

 

I believe a lot has to do with how many "units" one anticipates to sell. Regarding one offs, my guess would be maybe 80% research, development, CAD, original mock up, molds, final mock up and testing. The more that can be sold the more the price can come down. This must be balanced against the higher the price, the fewer that will be sold.

You can understand, without patents pending, some companies just copy designs and go along their merry way making money with an original thought of their own or the associated costs of development.

The $900.00 you listed above may be the current price of a splitter, however it doesn't come close to the actual direct costs of the parts currently included from the throttle body to where you connect to the heads. These parts would be TB's, splitter, plenums, injector manifolds, injectors, linkage, servo motors, linkage and fuel rails. Understand this is the area being developed and modified. Some of these arts were done away with, some combined and incorporated and others were added to.

In the past, for the most part, we have given away the development costs as many of our ideas were free for the taking. The few exceptions were the ones with real costly development. The costs of this plenum are not unlike the development costs associated with the 996tt intake cams. Prior to our venturing into the intake cams issue we were aware of no one who offered anything but exhaust cam variations ....... and for good reason at the time.

 

Sorry, I have received the drawings (which I can't post) but not the video's. Will post video as soon as I receive.