RSR crankcase breather
09-10-2005, 02:06 PM
#1
RSR crankcase breather
A while back a member, I think Wulf posted something about a rsr crankcase breather.
"Crankcase valve is reported to give you 5 - 10 hp. Costs about $100. I will post part number in a couple of days when I get home. It works by creating a lower pressure in the crankcase. On the Mk 1 you have to machine one end to make it fit but any good shop can do it.
The problem is that you need to pull the gearbox out to get to it. No problem for all you blokes revved up to install a SMF.
Has anyone tried this on their MKII GT3 and does this work or is it even worth doing?
R
"Crankcase valve is reported to give you 5 - 10 hp. Costs about $100. I will post part number in a couple of days when I get home. It works by creating a lower pressure in the crankcase. On the Mk 1 you have to machine one end to make it fit but any good shop can do it.
The problem is that you need to pull the gearbox out to get to it. No problem for all you blokes revved up to install a SMF.
Has anyone tried this on their MKII GT3 and does this work or is it even worth doing?
R
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10-01-2005, 02:21 PM
#8
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you should also use the Front main seal from the RS/RSR 996.102.264.92 advailable via PMSNA
(BTW this seal also fits the 964 cup & 993 Cup/RS/RSR series cars)
Mine will go when i install my custom Crank case breather
(BTW this seal also fits the 964 cup & 993 Cup/RS/RSR series cars)
Mine will go when i install my custom Crank case breather
10-02-2005, 11:10 PM
#9
Burning Brakes
Is it safe to say, this is not an easy diys job and can't be done without dropping the gear box. Glen mentioned removing the throttle body to get to it? If so, can it be reached from the top?
10-03-2005, 06:20 AM
#10
Instructor
When I emailed Gert about this he said it was easy to change.There does seem to alot of confusion about the ease with which this mod can be carried out.
A definative answer would be useful.
Shane
A definative answer would be useful.
Shane
10-03-2005, 10:11 AM
#12
Burning Brakes
I, for one, would be very grateful for someone with actual experience to chime in and take some of the mystery from this topic. Is it easy after the gear box is out? Or can it be accessed realistically without messing with the gear box?
Also the rationale for the change would be of great interest, how do you get 10 hp out of the crank case? Anything to do with windage?
Also the rationale for the change would be of great interest, how do you get 10 hp out of the crank case? Anything to do with windage?
10-03-2005, 12:08 PM
#13
My entire sum of wisdom on the subject:
First off, no sane mechanic will want to do this without dropping the tranny-- save it for a RMS job or LWF mod. How does it work? It changes the relative pressure inside the crankcase, that's all I know, as it vents. It's a Cupcar thing. The mod is good for a real 8 h.p., which most people won't notice on a given lap, so don't make yourself crazy over it. Appearance: The part looks like a standard-issue black hexagonal fitting-- I had a few fab'd up because Motorsport was back-ordered for months after some Rennlisters got overly excited over Wulfie's first post
Lee in D.C.
'04 RS Clone
First off, no sane mechanic will want to do this without dropping the tranny-- save it for a RMS job or LWF mod. How does it work? It changes the relative pressure inside the crankcase, that's all I know, as it vents. It's a Cupcar thing. The mod is good for a real 8 h.p., which most people won't notice on a given lap, so don't make yourself crazy over it. Appearance: The part looks like a standard-issue black hexagonal fitting-- I had a few fab'd up because Motorsport was back-ordered for months after some Rennlisters got overly excited over Wulfie's first post
Lee in D.C.
'04 RS Clone
10-05-2005, 03:10 AM
#14
Technical Guru
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On earlier models (964, 993) you need to modify the engine sealing system before you can install a one-way crankcase breather, does the same apply to the regular GT3? (and is the additional sealing anything more than using the RSR RMS or the front pulley seal?)
Here's the motorsport's piece
Here's the motorsport's piece
Originally Posted by Robert Linton
with a dry sump boxer type engine in particular, a one-way check valve with certain resistance characteristics prohibits air from flowing from the oil tank into the crankcase thereby creating a vacuum in the crankcase which, in turn, permits the pistons to move more freely as air resistance is dissipated thereby producing additional horsepower. Depending upon which oil pump is used (as increased oil pump suction capacity increases vacuum), this might be in the range of 7 HP to 10 HP in race cars. As to street cars, after considerable dyno testing, it was determined to be appropriately 5 horsepower.
Last edited by JasonAndreas; 10-05-2005 at 03:37 AM.