KA - In Memory of my Mom (Vincee) and best friend Michael J. Maring
#3601
09-14-2010, 09:34 PM
Yeah, the rally car racing world uses it, but they replace stuff daily in those motors. Dumping raw fuel into your exhaust manifold is destructive to a 40k engine. Ferrari had their own system for a while which seemed better. It used a bypass valve from the intake manifold to the exhaust manifold. When you let off the gas the bypass valve open and compressed air from the intake was let into the exhaust system, and with the combination of slightly retarded timing for excess fuel, ignition occurred and bam boost. The difference was that instead of retarding timing 20-40 degrees they could do it far less, basically just enough for excess fuel to mix with the new air. Much safer but I am sure it still took it's toll on the system. Another way was to add an extra fuel injector to the exhaust pre-turbine to get the same effect without retarding timing. all of these are bad for the engine, turbos, cats. I had another idea but who knows if it will ever work.
I guess if you have a 5k motor it's no big deal to do this stuff.
I guess if you have a 5k motor it's no big deal to do this stuff.
After looking at the different options for getting the power to the road I am convinced eliminating the viscous coupling and replacing the stock front differential with an electronic controlled multi clutch LSD differential capable of harnessing 400 to 500 of the motors available hp/torque would be ground breaking all the way around for the 996tt platform. I believe existing performance records will be shattered.
The fact is the stock front differential is useless and short of top speed power levels above 700-800 hp buy little with much power never seeing the road. Removing the front differential doesn't really make significant gains as power is till wasted. The bad news is there isn't a differential currently on the market that is electronic controlled through ECU, fit in our available space and handle our power specifications. The good news is it appears there is a manufacturer who will work with us to design and build what we specify.
Should have a time frame for this differential's production shortly.
Last edited by cjv; 09-14-2010 at 09:41 PM.
#3603
09-18-2010, 03:23 PM
We are assembling the fuel system. We will be utilizing a total of five fuel pumps. There will be two #10 supply lines each being fed by two pumps. The return line will be a #8. There will be one pump supplying a #8 line for the nitrous.
#3604
09-18-2010, 03:58 PM
We are looking into the Getrag 630 Top front electronic differential. It is rated for 400 Nm or 295.0248 lb-ft torque. This unit would allow us to eliminate the viscous coupling. This unit would fit in our space allowance. It is about 100 lb-ft torque shy of what we were looking for.
Currently checking with Getrag to see if the torque rating could be ungraded.
Currently checking with Getrag to see if the torque rating could be ungraded.
Last edited by cjv; 09-18-2010 at 07:56 PM.
#3605
09-18-2010, 08:02 PM
Here is a good description I found regarding the stock 996tt front differential. It was not designed for traction but rather stability and balanced steering in the bends. At the most, without loss of traction it handles 20 hp/torque.
The multiple plate viscous coupling is housed in the front axle transmission, conveying drive forces to the front wheels and compensating any difference in speed between the front and rear axles. Like a multiple plate differential, the coupling is made up of inner and outer plates, the former connected to the hub, the latter to the housing. Silicon fluid in the sealed area in between them serves to convey power to the front axle by means of the shear forces between the fluid and the plates whenever there is a difference in speed.
One of the advantages of this four wheel drive technology is that the car does not "push" hard over the front wheels in a bend and thus remains neutral on winding roads and quite generally under all conditions. A further advantage, particularly for a sports car, is the low weight, the entire four wheel drive system weighing in at 121 lb.
The multiple plate viscous coupling is housed in the front axle transmission, conveying drive forces to the front wheels and compensating any difference in speed between the front and rear axles. Like a multiple plate differential, the coupling is made up of inner and outer plates, the former connected to the hub, the latter to the housing. Silicon fluid in the sealed area in between them serves to convey power to the front axle by means of the shear forces between the fluid and the plates whenever there is a difference in speed.
One of the advantages of this four wheel drive technology is that the car does not "push" hard over the front wheels in a bend and thus remains neutral on winding roads and quite generally under all conditions. A further advantage, particularly for a sports car, is the low weight, the entire four wheel drive system weighing in at 121 lb.
Last edited by cjv; 09-18-2010 at 08:54 PM.
#3607
09-20-2010, 07:51 PM
#3608
09-20-2010, 08:30 PM
I never thought a front differential and housing could be so complex. 
The electronic units don't seem to be able to handle the power. The aftermarket units seem to have a fitment issue. No one appears to have what we want or need. We could have one designed and made from scratch ...... that would be more expensive that a 996tt motor.
After many hours of conversing with some of the best minds in the industry I realized we could remove our stock differential housing, send it somewhere
and have all the guts removed and build our own adjustable LSD with larger splines/axles.
All this for a lot less money than doing it from scratch.
If all goes well I will be giving a go ahead to produce in about a week. I believe we have another first on the horizon.
The electronic units don't seem to be able to handle the power. The aftermarket units seem to have a fitment issue. No one appears to have what we want or need. We could have one designed and made from scratch ...... that would be more expensive that a 996tt motor.
After many hours of conversing with some of the best minds in the industry I realized we could remove our stock differential housing, send it somewhere
and have all the guts removed and build our own adjustable LSD with larger splines/axles. All this for a lot less money than doing it from scratch.
If all goes well I will be giving a go ahead to produce in about a week. I believe we have another first on the horizon.
Last edited by cjv; 09-20-2010 at 08:32 PM.
#3610
09-21-2010, 06:26 PM
This will be a one off project as gear manufacturers generally want 20 set minimums.What is going to occur is we are going to buy a front case/differential from a dismantler and ship it to a certain company which will be announced later. This manufacturer wants X amount of dollars and four months to build what we agree on.
What is basically going to happen is we will utilize the case and gut out everything else. The viscous coupling will go bye bye and a certain type adjustable LSD will be made and installed along with all required upgraded bearings.
In other words 50% of the power will go to the rear tires and 50% will be directed to the front tires. When tires lose traction the LSD's will lock the fronts and/or rears based on the adjustable ratio we dial in.
I have been explained this set up would be difficult to handle in some turns if the motor does not have the ability to break traction in a particular turn. KA will have zero issues with it's ability to break traction at will so this set up should work well.
It also appears the axle diameters ...... although small by comparison can be upgraded metal wise to accomplish the task of the smaller front tires. If not, custom larger diameter front axles can be made.
It will be a few more weeks before I have some real good information.
Last edited by cjv; 09-21-2010 at 06:30 PM.
#3611
09-21-2010, 06:33 PM
I am no expert but would not that power distribution introduce power on understeer? With the significant rear weight bias, maybe a slight rear bias would be a good thing? What are your thoughts on it?
#3612
09-21-2010, 07:07 PM
I intend to put some hours on just such a type of set up before fully committing. I'll let you know then.
germeezy1, the following is an excellent read regarding your question ....... make sure you read both pages.
http://www.rallycars.com/Cars/4wd_turbo_cars.html
Hope it helps.
Last edited by cjv; 09-21-2010 at 09:06 PM.
#3613
09-22-2010, 07:19 PM
The fuel system was given a go ahead today.
I about fell over when I saw the price of the Goodridge 10 AN/FT 811 Teflon fuel hose ....... $43.10 per foot.
One additional thing I learned about the four main fuel pumps. Two will be in constant operation. The other two main fuel pumps will come online automatically at a certain boost.
The fuel system will take about fifty hours to install.
I about fell over when I saw the price of the Goodridge 10 AN/FT 811 Teflon fuel hose ....... $43.10 per foot.
One additional thing I learned about the four main fuel pumps. Two will be in constant operation. The other two main fuel pumps will come online automatically at a certain boost.
The fuel system will take about fifty hours to install.
#3615
09-24-2010, 03:12 PM
The fuel system was given a go ahead today.
I about fell over when I saw the price of the Goodridge 10 AN/FT 811 Teflon fuel hose ....... $43.10 per foot.
One additional thing I learned about the four main fuel pumps. Two will be in constant operation. The other two main fuel pumps will come online automatically at a certain boost.
The fuel system will take about fifty hours to install.
I about fell over when I saw the price of the Goodridge 10 AN/FT 811 Teflon fuel hose ....... $43.10 per foot.
One additional thing I learned about the four main fuel pumps. Two will be in constant operation. The other two main fuel pumps will come online automatically at a certain boost.
The fuel system will take about fifty hours to install.