Home  |  Forums  |  914 Info  |  Blogs
 
914World.com - The fastest growing online 914 community!
 
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.
 

Welcome Guest ( Log In | Register )

 
Reply to this topicStart new topic
> RPM limits for transmission?
smontanaro
post Apr 25 2010, 06:57 PM
Post #1


Senior Member
***

Group: Members
Posts: 1,190
Joined: 3-June 05
From: Evanston, IL
Member No.: 4,197
Region Association: Upper MidWest



In the 914 EV conversion world a number of people have reported vibration problems with their conversions. Here's the latest example: Peter's Blog (see the April 6 post). While the author is thinking the flywheel needs balancing, I suspect it's more likely to be an issue with the transmission. Scrolling through his old blog posts I see the transmission was rebuilt during the conversion process, so maybe the flywheel is the problem (especially if it had been balanced with the crank at one time). What were 901 & 915 transmissions designed for as far as input rpm? Is it possible that even with the rebuild it just can't tolerate input rpms in the 5k range on a regular basis? What sort of time does a racing engine spend about 5k?

Skip
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
sean_v8_914
post Apr 25 2010, 07:21 PM
Post #2


Chingon 601
****

Group: Members
Posts: 4,011
Joined: 1-February 05
From: San Diego
Member No.: 3,541



we know why Peter's EV 914 vibrates:
1. the EV conversion motor is solid mounted to the engine bar
2. engine bar is solid mounted to chassis
3. clutch and flywheel was not balanced
4. EV motor hub was not balanced
5. solid mounts of any kind are the handywork of Satan himself
6. harmonics are a bitch
7. 10 year old tires dont help much either
8. clutch package designed for WAY different operating parameters (inertia, mass...)

the 10jereen's 901 lives mostly over 5000rpm
many of my six customers have hot track-rat motors that rarely dip below 5000 rpm
I have run 901 in teh 8000 range and they live just fine
...it aint the box.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Chris Pincetich
post Apr 26 2010, 11:15 AM
Post #3


B-)
****

Group: Members
Posts: 2,082
Joined: 3-October 05
From: Point Reyes Station, CA
Member No.: 4,907
Region Association: Northern California



(IMG:style_emoticons/default/agree.gif)
Race 901s are in the 5-8k RPM range all the time. It is likely other rotating components that are out of balance.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post

Reply to this topicStart new topic
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:

 



- Lo-Fi Version Time is now: 16th May 2024 - 12:32 PM