![]() |
|
Porsche, and the Porsche crest are registered trademarks of Dr. Ing. h.c. F. Porsche AG.
This site is not affiliated with Porsche in any way. Its only purpose is to provide an online forum for car enthusiasts. All other trademarks are property of their respective owners. |
|
![]() |
Randal |
![]()
Post
#1
|
Advanced Member ![]() ![]() ![]() ![]() Group: Members Posts: 4,446 Joined: 29-May 03 From: Los Altos, CA Member No.: 750 ![]() |
|
![]() ![]() |
sww914 |
![]()
Post
#2
|
Advanced Member ![]() ![]() ![]() ![]() Group: Members Posts: 2,439 Joined: 4-June 06 Member No.: 6,146 Region Association: None ![]() |
One of the shops at Buttonwillow has a dyno that's not too expensive.
Chris, what's the advantage of Rabbit rods? |
Chris Hamilton |
![]()
Post
#3
|
Senior Member ![]() ![]() ![]() Group: Members Posts: 611 Joined: 7-March 06 From: Berkeley, CA Member No.: 5,687 ![]() |
One of the shops at Buttonwillow has a dyno that's not too expensive. Chris, what's the advantage of Rabbit rods? That would be nice, I'm sure cliff would be up for it. The rabbit rods fix the fact that the 914 didn't come with a very good rod-length ratio. The 914 engine doesn't "breathe" very well, and the increased rod-length ratio improves that. If you want the physics explanation, you get that Work equals the dot product of the force and direction vectors. W = F • d, which simplified for a 2-dimensional scenario becomes W = F * d * cos ( theta ). If you increase the rod length you decrease the change in angle caused by the sweep of the connecting rod and minimize the potential range of theta. Steve, you've driven Cliff's car, right? This rod length change manifests itself in a bunch more bottom end power. |
grantsfo |
![]()
Post
#4
|
Arrrrhhhh! ![]() ![]() ![]() ![]() Group: Members Posts: 4,327 Joined: 16-March 03 Member No.: 433 Region Association: None ![]() |
One of the shops at Buttonwillow has a dyno that's not too expensive. Chris, what's the advantage of Rabbit rods? That would be nice, I'm sure cliff would be up for it. The rabbit rods fix the fact that the 914 didn't come with a very good rod-length ratio. The 914 engine doesn't "breathe" very well, and the increased rod-length ratio improves that. If you want the physics explanation, you get that Work equals the dot product of the force and direction vectors. W = F • d, which simplified for a 2-dimensional scenario becomes W = F * d * cos ( theta ). If you increase the rod length you decrease the change in angle caused by the sweep of the connecting rod and minimize the potential range of theta. Steve, you've driven Cliff's car, right? This rod length change manifests itself in a bunch more bottom end power. So are you increasing stroke with these rods? What size cylinders and pistons? What is stroke? Assuming you are increasing displacement and compression ratio too? It makes sense if you stroke a stock 2.0 that you would get more displacement and power. |
Chris Hamilton |
![]()
Post
#5
|
Senior Member ![]() ![]() ![]() Group: Members Posts: 611 Joined: 7-March 06 From: Berkeley, CA Member No.: 5,687 ![]() |
So are you increasing stroke with these rods? What size cylinders and pistons? What is stroke? Assuming you are increasing displacement and compression ratio too? It makes sense if you stroke a stock 2.0 that you would get more displacement and power. Nah, rod length doesn't affect stroke, the offset of the crank journals is the only factor in determining stroke. We keep the compression low so it will run on pump gas, compression is basically the same as stock. Cylinders are iron 94mm. |
grantsfo |
![]()
Post
#6
|
Arrrrhhhh! ![]() ![]() ![]() ![]() Group: Members Posts: 4,327 Joined: 16-March 03 Member No.: 433 Region Association: None ![]() |
So are you increasing stroke with these rods? What size cylinders and pistons? What is stroke? Assuming you are increasing displacement and compression ratio too? It makes sense if you stroke a stock 2.0 that you would get more displacement and power. Nah, rod length doesn't affect stroke, the offset of the crank journals is the only factor in determining stroke. We keep the compression low so it will run on pump gas, compression is basically the same as stock. Cylinders are iron 94mm. Oh assumed you were doing something differnt with crank. So just compression is being increased. What kind of compression? How long are these rods? |
![]() ![]() |
![]() |
Lo-Fi Version | Time is now: 26th June 2024 - 12:21 AM |
All rights reserved 914World.com © since 2002 |
914World.com is the fastest growing online 914 community! We have it all, classifieds, events, forums, vendors, parts, autocross, racing, technical articles, events calendar, newsletter, restoration, gallery, archives, history and more for your Porsche 914 ... |