Parts Catalog Accessories Catalog Tech Info Tech Forums
 
  Search our site:    
 Cart  | Project List | Order Status | Help    



Go Back   Pelican Parts Technical BBS > 1- Porsche Technical Forums > 911 / 930 Turbo & Super Charging Forum

Reply
 
LinkBack Thread Tools Rate Thread
Author
Thread Post New Thread    Reply
Twins are more fun!
 
JMA-RUF's Avatar
 
Join Date: Dec 2005
Posts: 639
Question Top end rebuild?

If I do a top-end rebuild on my 3.2 Carrera, do you guys recommend replacing the 9.5:1 pistons and slipping in some JE Turbo pistons?

I want to be able to run 1.2+ bar of boost later, but don't want to go with the half finned 930 cylinders. I like the fully finned Carrera cylinders. I can't afford to bore them out, so I want to stick to 3.2L, but use proper forged turbo pistons.

Any recommendation on compression ratio? Car will be mainly street but see some track time, so it will see sustained high boost for long periods. I'm wondering if 7.0:1 would be good, especially since I intend to run around 1.2bar later on?
__________________
James
Carrera TT

(3.3, Protomotive MAP ECU, EFI, GT2 EVO CAMs, Twin Plugged, Twin Turbo's)
Old 01-31-2007, 02:16 PM
  Pelican Parts Technical Article Directory    Reply With Quote #1 (permalink)
Registered User
 
Porschefile's Avatar
 
Join Date: Jun 2004
Location: Austin, TX
Posts: 150
If you want to run ~1.2bar of boost then you definitely want to go with different pistons for lower than 9.5:1 CR, unless you want to run around on $10+/gal race gas all the time. Are you still using the Motronic? If so, I'd tend to think something around ~8.0:1 or 8.5:1 would be good. Much lower than 8.0:1 and you'll start to loose a decent amount of response and low-end power. Hopefully someone with more experience will chime in but, those are my personal opinions. I believe my Carrera is either 7.0:1 or 7.5:1 (Mahle low CR pistons) and I'll say this much, the car is laggy and has crappy low-end performance considering the displacement though I plan on big boost so I'm sticking with it.
Old 01-31-2007, 05:30 PM
  Pelican Parts Technical Article Directory    Reply With Quote #2 (permalink)
Twins are more fun!
 
JMA-RUF's Avatar
 
Join Date: Dec 2005
Posts: 639
I guess the effect of "lag" can be combatted by using decent headers and a properly matched turbo though, right?

I'd gladly sacrifice a bit of low end response for an extra .2bar of boost. An extra 3psi has the potential for ~50-60 extra HP. I doubt a 1/2 point increase in compression ratio will give you that?

Just throwing thoughts up in the air... please keep the advice coming
__________________
James
Carrera TT

(3.3, Protomotive MAP ECU, EFI, GT2 EVO CAMs, Twin Plugged, Twin Turbo's)
Old 01-31-2007, 05:53 PM
  Pelican Parts Technical Article Directory    Reply With Quote #3 (permalink)
Reply

Thread Tools
Rate This Thread
Rate This Thread:

 


All times are GMT -8. The time now is 12:46 PM.


 
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2016, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2016 Pelican Parts - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page
 

DTO Garage Plus vBulletin Plugins by Drive Thru Online, Inc.