High horsepower built 996tt owners ...chime in!!
#46
07-13-2010, 12:07 AM
yeah ....... your little bird is Koro out of Germany. www.koro.de Been there and done that. 
The 996tt and 997tt are basically the same. I have discussed and examined Koro. They claim a 112 mm bucket and 84 mm crank to get 5L. There isn't enough room for 112 mm liners unless you siamese the liners. Sort of that you have to lengthen the case and the heads. Regarding the crank, we could not get a crank in a Porsche case any larger than 82.4 mm because of case wall and oil pump clearance problems. Then again changing the case dimensions will work.
Finally, a stock Porsche has a rod to piston ratio of about 1.64-1. It starts to get on the outer limits with a ratio below 1.60-1. KA has a ratio of about 1.58-1 ......... this is a result of rods with a length of approx. 130 mm. I believe stock is approx. 126 mm. I would have liked to had 132-134 mm. The only way to raise the ratio and reduce piston speed is to lengthen the rod length. Surprise ...... to get to 130 mm required offsetting piston center on each bank, raising the wrist pin into the oil ring and reducing the diameter on the wrist pin. There is no more room for any longer rod length. Now imagine the rod length required for a 84.0 mm crank.
You go too much below the 1.6 ratio, your pistons will travel too fast, you drastically lower your red line and you motor has a tendency to go boom. On the plus side your torque will be in never never land.
Short of raising the deck height you can't gain any more rod length.
Now we looked at raising the deck height with spacers or billet custom case but alias you have issues with the timing chain. Talk about throwing money into a deep dark hole.
Finally Koro has built large displacement 996 motors up to 5L, however they are normally aspirated. I don't believe you will presently find a turbo 996/997 motor larger than 4.3 or 4.4L.
This is as I know things today. You have to remember in 2001, 450/500 hp was king on the street and a little bit earlier Porsche won LeMans with a staggering 600 hp. Everything may change tomorrow. Hell, throw enough money at it and it can be done, however be laying down when you get the bill.
The 996tt and 997tt are basically the same. I have discussed and examined Koro. They claim a 112 mm bucket and 84 mm crank to get 5L. There isn't enough room for 112 mm liners unless you siamese the liners. Sort of that you have to lengthen the case and the heads. Regarding the crank, we could not get a crank in a Porsche case any larger than 82.4 mm because of case wall and oil pump clearance problems. Then again changing the case dimensions will work.
Finally, a stock Porsche has a rod to piston ratio of about 1.64-1. It starts to get on the outer limits with a ratio below 1.60-1. KA has a ratio of about 1.58-1 ......... this is a result of rods with a length of approx. 130 mm. I believe stock is approx. 126 mm. I would have liked to had 132-134 mm. The only way to raise the ratio and reduce piston speed is to lengthen the rod length. Surprise ...... to get to 130 mm required offsetting piston center on each bank, raising the wrist pin into the oil ring and reducing the diameter on the wrist pin. There is no more room for any longer rod length. Now imagine the rod length required for a 84.0 mm crank.
You go too much below the 1.6 ratio, your pistons will travel too fast, you drastically lower your red line and you motor has a tendency to go boom. On the plus side your torque will be in never never land.
Short of raising the deck height you can't gain any more rod length.
Now we looked at raising the deck height with spacers or billet custom case but alias you have issues with the timing chain. Talk about throwing money into a deep dark hole. Finally Koro has built large displacement 996 motors up to 5L, however they are normally aspirated. I don't believe you will presently find a turbo 996/997 motor larger than 4.3 or 4.4L.
This is as I know things today. You have to remember in 2001, 450/500 hp was king on the street and a little bit earlier Porsche won LeMans with a staggering 600 hp. Everything may change tomorrow. Hell, throw enough money at it and it can be done, however be laying down when you get the bill.
#47
07-13-2010, 01:26 PM
Jags,
Are you going to take the car to the track soon? I noticed you're local and I'd love to see that thing make a pass then watch them say, "excuse me sir you cannot come back until you have an nhra full cage."
Erik
Are you going to take the car to the track soon? I noticed you're local and I'd love to see that thing make a pass then watch them say, "excuse me sir you cannot come back until you have an nhra full cage."
Erik
#52
07-16-2010, 12:01 PM
The "Monster" left my garage a while back, it has been very tough for me. Appreciate all the kind words.
-Art
-Art
#55
07-17-2010, 10:10 AM
As you know my car made 1109AWHP....I get her back tomorrow with a pump file and we will have those numbers tomorrow am (she made 757RWHP on the prior setup). I will have the race file in Mid August when Todd Z come down. I can probably answer your question in 6 months. I dont feel comfortable saying reliable now for obvious reasons.
Where is Joe and Bryant?
Jag
Where is Joe and Bryant?
Jag
Who is your tuner if I may ask?
~SC
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