Rotrex Supercharger thread - Rennlist - Porsche Discussion Forums

Notices
928 Forum
Sponsored by:
Sponsored by: 928 Specialists

Rotrex Supercharger thread

 
Old 09-21-2012, 12:42 PM
  #1  
SeanR
Running up the Odo'
Rennlist Member
Thread Starter
 
SeanR's Avatar
 
Join Date: Apr 2006
Location: DFW Texas
Posts: 34,325
Default Rotrex Supercharger thread

Just so we can have several different threads on this discussion.

Discuss.
SeanR is offline  
Old 09-21-2012, 01:03 PM
  #2  
auzivision
Super User
 
auzivision's Avatar
 
Join Date: Jun 2006
Location: Indianapolis Area
Posts: 2,593
Default

Rotrex suck and Vortechs blow… or is it the other way around.

Who knows, it’s all ball bearing nowadays!

Name:  Ball bearings.jpg
Views: 9332
Size:  58.0 KB
auzivision is offline  
Old 09-21-2012, 01:39 PM
  #3  
rgs944
Super User
 
rgs944's Avatar
 
Join Date: Jan 2010
Location: Nebraska
Posts: 3,306
Default

I will maybe be upgrading my clutch disk sometime in the next few years and going to the smaller pulley. Not sure aobut intercooling but maybe. For right now the car feels great to keep me satisfied. The thing I always tell people is that the boost seems to kick in early with the Rotrex. I know some of the complaints with some other SC kits is that people say you need to be in the upper rev ranges to usel the extra power. That does not seem to be so with this kit. It just makes it so much more drivable through traffic, like someone is just giving you a little nudge from behind as you barely press the pedal past 3000rpm.
rgs944 is offline  
Old 09-21-2012, 02:59 PM
  #4  
SeanR
Running up the Odo'
Rennlist Member
Thread Starter
 
SeanR's Avatar
 
Join Date: Apr 2006
Location: DFW Texas
Posts: 34,325
Default

I started this one because Victor said he wasn't going to post in the other thread. Not sure why, but here it is.
SeanR is offline  
Old 09-21-2012, 03:07 PM
  #5  
Jherriott
Addict
Rennlist Member
 
Jherriott's Avatar
 
Join Date: Mar 2010
Location: Toronto, Ontario
Posts: 654
Default

Isn't the boost constant with a supercharger as it is belt driven right off the crank? Shouldn't it feel like a NA motor with more displacement? Whereas a turbo has boost and lag issues because the time required to spin the turbo up only begins when you start to accelerate and gain positive manifold pressure?
Jherriott is offline  
Old 09-21-2012, 03:20 PM
  #6  
Cosmo Kramer
Addict
Rennlist Member
 
Cosmo Kramer's Avatar
 
Join Date: Jan 2009
Location: On boost
Posts: 4,225
Default

Originally Posted by Jherriott View Post
Isn't the boost constant with a supercharger as it is belt driven right off the crank? Shouldn't it feel like a NA motor with more displacement? Whereas a turbo has boost and lag issues because the time required to spin the turbo up only begins when you start to accelerate and gain positive manifold pressure?
A centrifugal supercharger is like a belt driven turbo, the faster they spin the more boost you get (Rotrex and Vortech). A Roots or twin screw supercharger moves a higher volume of air at low RPM and will give more consistent boost throughout the RPM range. However, they tend to have less peak, high rpm power than the centrifugal superchargers. Its all a trade off.
Cosmo Kramer is offline  
Old 09-21-2012, 05:10 PM
  #7  
SeanR
Running up the Odo'
Rennlist Member
Thread Starter
 
SeanR's Avatar
 
Join Date: Apr 2006
Location: DFW Texas
Posts: 34,325
Default

As I said in the other thread, the reason I picked this kit over other options was ease of install and price. Mine is my daily driver so it made the most sense if I needed to take it off in quick manner and put the car back to pre-boost conditions. I keep my current fans, no cutting or any other serious modifications needed. With just a small bit of tuning this thing pulls great and at this time, is just what I need in additional power. With the option of a significant increase when I feel like playing around with it.
SeanR is offline  
Old 09-21-2012, 05:24 PM
  #8  
Cosmo Kramer
Addict
Rennlist Member
 
Cosmo Kramer's Avatar
 
Join Date: Jan 2009
Location: On boost
Posts: 4,225
Default

Victor: What psi do the various pullies produce on your installs?
Cosmo Kramer is offline  
Old 09-21-2012, 06:33 PM
  #9  
victor25
Addict
Rennlist Member
 
victor25's Avatar
 
Join Date: Oct 2009
Location: Michigan... Grand Rapids
Posts: 718
Default

Basically 80mm is 6+, 75mm is 8+, and the 70mm is 10+
I have not graphed the 70mm though... I have a feeling it may be more, as Jeff was getting some serious boost to his intercooler and MAF boot with his 70mm pulley and things kept coming apart. He even broke a weld on a clamp.
victor25 is offline  
Old 09-21-2012, 06:52 PM
  #10  
Jon B.
User
 
Jon B.'s Avatar
 
Join Date: Feb 2005
Location: Linden, NC
Posts: 1,368
Default

What headunit is being used?
Jon B. is offline  
Old 09-21-2012, 06:56 PM
  #11  
anonymousagain
Addict
Rennlist Member
 
anonymousagain's Avatar
 
Join Date: Nov 2005
Location: NorCal - Bay Area
Posts: 861
Default

so the dyno graph matches your sig for stage1 and stage1 is 6psi?

Stage1 Rotrex supercharged
481 RWHP and 426 torque
anonymousagain is offline  
Old 09-21-2012, 07:15 PM
  #12  
Cosmo Kramer
Addict
Rennlist Member
 
Cosmo Kramer's Avatar
 
Join Date: Jan 2009
Location: On boost
Posts: 4,225
Default

Originally Posted by victor25 View Post
Basically 80mm is 6+, 75mm is 8+, and the 70mm is 10+
I have not graphed the 70mm though... I have a feeling it may be more, as Jeff was getting some serious boost to his intercooler and MAF boot with his 70mm pulley and things kept coming apart. He even broke a weld on a clamp.
Did you have the 80mm pulley installed on your dyno pull? You said in the other thread that you let it go past 6 psi, how far past? Just curious to see what the Rotrex is putting down per psi vs us Vortech guys. I am sure it is more, but that 155 hp gain points to a minimum of 8 psi.
Cosmo Kramer is offline  
Old 09-21-2012, 08:20 PM
  #13  
rgs944
Super User
 
rgs944's Avatar
 
Join Date: Jan 2010
Location: Nebraska
Posts: 3,306
Default

Another thing I really like about Victors kit is the SC bracket. I know there were some issues in the past about twisiting over time on some other kits. Obviously time will be the true test but seeing this bracket set up it looks very solid for the long term. I think the build qaulity and engineering of the bracket is up to the standard a 928 should have.
rgs944 is offline  
Old 09-21-2012, 08:35 PM
  #14  
victor25
Addict
Rennlist Member
 
victor25's Avatar
 
Join Date: Oct 2009
Location: Michigan... Grand Rapids
Posts: 718
Default

Originally Posted by Jon B. View Post
What headunit is being used?
c38-91

What you guys need to understand, is that I have made many many dyno pulls, and their have been many changes to the setup over the year, or years, in trying to create an inexspensive, easy to install, powerful, and versital setup. I started with a 100 mm pulley and custom fuel rails... then added an idler pulley to deal with belt slip. Then went to 70mm, but still not much boost until I realized the belt was stretching, so I removed the idler and installed a tensioner, and bang huge boost! So I went back to the 100mm, added the 36lb injectors, and started shark tuning. I have tons of logs with everything from 4lbs boost to 11lbs. With different injectors, with custom and now stock rails, with and without an intercooler, etc etc ect... Huge time has gone into developing this, and the last piece of the puzzle, which was supposed to be done weeks ago and is the intakes for the filters is almost finished.
Simply put, we are supplying a kit that you can use as a daily driver, or create you own HP monster with. So keep it simple and safe or go crazy, its up to you!! I have intercoolers built and ready to go for pep's that want to go crazy. Hey put a custom 60mm pulley on there and go crazy with 20psi and a chiller setup... I don't care, it's your car.

I am looking forward to seeing what kind of dynos people will post.
victor25 is offline  
Old 09-21-2012, 08:40 PM
  #15  
daveo90s4
User
 
Join Date: Feb 2006
Location: Australia
Posts: 598
Default

Victor how do I find out more about this kit? Technical information. Installation issues. Whether it will fit on a RHD car (brake booster on RH side, etc. whether there is an IC option. Whether there is a lesser 5 psi pulley / boost option. How the air cleaner system works. What is done to prevent the maf boot coming off under boost. Whether a rrfp regulator is needed. That sort of stuff and more. Thanks Dave
daveo90s4 is offline  

Thread Tools
Search this Thread
Quick Reply: Rotrex Supercharger thread


Contact Us About Us Advertising Cookie Policy Privacy Statement Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: