|
|
|
|
| Author |
|
|
Registered
Join Date: Aug 2010
Location: NY & UK
Posts: 203
|
Urgent Help regarding PMO Brake Check Valve
I have just received a phone call from my mechanic telling me there is no Brake Servo assist with my PMO's and I am racing next week
 We have figured out that it already has space allocated for it on the left hand manifold (blocked off at the moment) and that it is some sort of Check Valve that needs installed... can anyone out there give me advice or pics on how to get around this issue. Thanks Steven |
||
05-26-2011, 02:36 AM
|
|
|
Moderator
Join Date: Dec 2001
Posts: 9,569
|
Why not ditch the servo bits and go with an unboosted master cylinder for better feel?
__________________
'66 911 #304065 Irischgruen ‘96 993 Carrera 2 Polarsilber '81 R65 Ex-'71 911 PCA C-Stock Club Racer #806 (Sold 5/15/13) Ex-'88 Carrera (Sold 3/29/02) Ex-'91 Carrera 2 Cabriolet (Sold 8/20/04) Ex-'89 944 Turbo S (Sold 8/21/20) |
||
|
05-26-2011, 05:03 AM
|
|
|
abit off center
|
You can also just go with a separate vacuum pump made just for this application. We are using one with our 2.7 running carbs and it works great.
__________________
______________________ Craig G2Performance Twinplug, head work, case savers, rockers arms, etc. |
||
|
05-26-2011, 05:18 AM
|
|
|
Registered
Join Date: Aug 2010
Location: NY & UK
Posts: 203
|
Thanks for replies... at the moment I need something super quick (reliable of course) as the car is racing next week, then I can look at better options
|
||
|
05-26-2011, 06:42 AM
|
|
|
Registered
Join Date: May 2003
Posts: 3,346
|
I don't think you need a check valve, but I also don't think vacuum from 1 cylinder will be enough for your booster. It seems to me that people who have used manifold vacuum tap into all or at least 3 cyliders. You just need to connect them all together into 1 line for the brake booster.
-Andy
__________________
72 Carrera RS replica, Spec 911 racer |
||
|
05-26-2011, 11:18 AM
|
|
|
Moderator
Join Date: Dec 2001
Posts: 9,569
|
Seriously, how many real race cars rely on vacuum boost for the brake system?
What chassis or year is the car based on?
__________________
'66 911 #304065 Irischgruen ‘96 993 Carrera 2 Polarsilber '81 R65 Ex-'71 911 PCA C-Stock Club Racer #806 (Sold 5/15/13) Ex-'88 Carrera (Sold 3/29/02) Ex-'91 Carrera 2 Cabriolet (Sold 8/20/04) Ex-'89 944 Turbo S (Sold 8/21/20) |
||
|
05-26-2011, 12:23 PM
|
|
|
|
abit off center
|
Quote:
LOL for us its not for the car but the age of the drivers  We have assist on our 74 and are still rather refreshed after 40 min..
__________________
______________________ Craig G2Performance Twinplug, head work, case savers, rockers arms, etc. |
||
|
05-26-2011, 01:08 PM
|
|
|
Registered
Join Date: Aug 2010
Location: NY & UK
Posts: 203
|
Guys, it's Racing Regulations, I can't change it!
I was told that one pipe would get me by (Left, centre manifold), I take it this is not the case then? Does PMO Manifold not have a single outlet in the centre? |
||
|
05-26-2011, 01:43 PM
|
|
|
120 HP/Liter is all I ask
|
I like cgarr's idea. Consistent vacuum with electric pump.
Here is Summit's list of them Vacuum Pumps, Street - SummitRacing.com
__________________
"It all started when I began looking around and just could not find my dream car. So I decided to build it myself” - Ferry Porsche |
||
|
05-28-2011, 07:12 PM
|
|
|
Registered
|
Hi Steven
Here is a picture of my new PMO 46's. You can see the brake vacume port coming off of the #2 intake manifold. There is also a small plastic one way valve to increase braking performance. Hope this helps. 
|
||
|
05-29-2011, 03:42 AM
|
|
|
Registered
Join Date: May 2001
Location: Peoples Republic of Long Beach, NY
Posts: 21,140
|
single line off the manifold is good for me with E-cams
more overlap may have issues?
__________________
Ronin LB '77 911s 2.7 PMO E 8.5 SSI Monty MSD JPI w x6 |
||
|
06-13-2011, 04:12 PM
|
|
1969 and 1986 Porsche Targa and Coupe 1720cc and 3
