Pelican Parts
Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help



Go Back   Pelican Parts Forums > Porsche Forums > 911 / 930 Turbo & Super Charging Forum


Reply
 
LinkBack Thread Tools Rate Thread
Author
Thread Post New Thread    Reply
Manassas, VA
 
lucittm's Avatar
 
Join Date: Apr 2007
Posts: 1,211
Garage
Intercooler Wiring Modification

Fellow Enthusiasts,
During a routine intercooler clean and inspect (my first one), I noticed that someone had spliced the two wires together that lead to the Boost Pressure Switch (white) and the Boost Pressure Transmitter (brown).
Has anyone else seen this? What would be the motivation to do this? I disconnected the offending and unauthorized splice modification and have noticed no difference. Of course, I don't have the proper tachometer, so I cannot monitor boost pressure.

Anyone have a spare 1991-1994 turbo tach with on-board computer (OBC)?
__________________
1991 964 Polar Silver Metallic Turbo Coupe
Old 06-29-2007, 08:01 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #1 (permalink)
E-85 sippin drunk
 
turbobrat930's Avatar
 
Join Date: Jan 2002
Location: Warner Robins, GA
Posts: 1,506
Instead of getting an OEM tach with the boost guage inside, why not get the mechanical boost guage that replaces the clock?? Them you dont have to rely on an electronical sending unit. You can have a hose that connects the boost guage directly to the I/C, so you know exactly how much boost you are running....

here, follow the link: http://www.nhspeedometer.com/911/custom_design/1.htm
__________________
Brad...930 gt-1 racecar, increased displacement to 3.6L, JB racing Cylinders, JE 8 to1 pistons, stroked crank, Carrillo rods, extrudehoned 3.2L intake, full bay Bell I/C, GT-2 EVO cams, Rarly8 headers, GTX-35RS turbo, twin plug, P&P heads, Link G4 EFi system, G-50/50 with LTD slip and oil squirters/oil cooler, zork tube, full race coilover system, with carbon fiber body, full cage, E-85 sippin drunk
Old 06-29-2007, 08:53 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #2 (permalink)
Manassas, VA
 
lucittm's Avatar
 
Join Date: Apr 2007
Posts: 1,211
Garage
North Hollywood Speedometer

Brad,
Thanks for that link, I was looking for it earlier to call them about the mod to the oil temp gauge that provides the numbers instead of just the lines.
__________________
1991 964 Polar Silver Metallic Turbo Coupe
Old 06-29-2007, 09:41 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #3 (permalink)
E-85 sippin drunk
 
turbobrat930's Avatar
 
Join Date: Jan 2002
Location: Warner Robins, GA
Posts: 1,506
no problem. I had them redo all of my gauges in my car, including raising my speedo to 200MPH, offseting my tach, custom colors and new glass and bezels. I also had several more VDO gauges, and they do those to match as well. Excellent quality.... highly recommended!!
__________________
Brad...930 gt-1 racecar, increased displacement to 3.6L, JB racing Cylinders, JE 8 to1 pistons, stroked crank, Carrillo rods, extrudehoned 3.2L intake, full bay Bell I/C, GT-2 EVO cams, Rarly8 headers, GTX-35RS turbo, twin plug, P&P heads, Link G4 EFi system, G-50/50 with LTD slip and oil squirters/oil cooler, zork tube, full race coilover system, with carbon fiber body, full cage, E-85 sippin drunk
Old 06-30-2007, 03:19 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #4 (permalink)
Manassas, VA
 
lucittm's Avatar
 
Join Date: Apr 2007
Posts: 1,211
Garage
Lightbulb Myster Solved

I think I answered my own question. A few days ago I was really standing on it and the car shut down like it hit a brick wall when I got to about 6000 RPMs. I read in the PEC that the function of the boost pressure switch is to remove the ground from the fuel pumps if the switch detects an over boost condition.

I have extra springs in my waste gate, so I probably was over 1.1 bar. The shocker though, was the dramatic reduction in acceleration. It came on so fast I was literally thrown forward and both hands nearly came off the wheel. Foolishly, I tested it once more and it was the same as the first time.

I guess the PO had this experience and crossed the wires to prevent the switch from opening and removing the ground signal (it is normally closed). I would not think the wire to the pressure transmitter (for the OBC boost guage) would be enough of a ground, but I guess it is.

Too bad the boost pressure switch is not adjustable. I will leave the modification off the car, but what fun is 1.1+ bar of boost if you can't use it?

Mark
__________________
1991 964 Polar Silver Metallic Turbo Coupe
Old 07-06-2007, 06:56 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #5 (permalink)
OFF THE BOOST PIPE NOW...
 
A930Rocket's Avatar
 
Join Date: Oct 2003
Location: Mount Pleasant, South Carolina
Posts: 7,368
You only have to ground the overboost wire. Not sure why he did both, but you found your answer.
Old 07-08-2007, 05:19 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #6 (permalink)
Manassas, VA
 
lucittm's Avatar
 
Join Date: Apr 2007
Posts: 1,211
Garage
930Rocket,
That is the funny part. The PO did NOT ground the boost pressure switch or the boost pressure transmitter, he simply wired them together. Imagine the letter X , that's what the pair of wires looked like.

Weird huh?

Mark
__________________
1991 964 Polar Silver Metallic Turbo Coupe
Old 07-09-2007, 07:41 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #7 (permalink)
Reply

Thread Tools
Rate This Thread
Rate This Thread:

 


All times are GMT -8. The time now is 01:04 PM.


 
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - 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.