smokey GTS following cat-less X pipe install
05-19-2012, 01:18 AM
#1
Instructor
Thread Starter
smokey GTS following cat-less X pipe install
Hi friends -
I installed an X-pipe (sans cats) with RMB and am very happy with the new found torque and extra horsepower but since I did the change out my exhaust belches out a blue cloud every time I decelerate. I guess this is a function of the lower back pressure without the cats. Previously oil consumption was about 1q/1500 miles and will check again with new system.
Anybody have the same/similar experience? I'm considering installing 300 cpi cats to get a little back pressure and perhaps "convert/burn" the oil that's slippingby in my low back pressure system.
All the best from Horseshoe Bay!
Joe
1993 GTS - X-pipe, no cats, RMB
I installed an X-pipe (sans cats) with RMB and am very happy with the new found torque and extra horsepower but since I did the change out my exhaust belches out a blue cloud every time I decelerate. I guess this is a function of the lower back pressure without the cats. Previously oil consumption was about 1q/1500 miles and will check again with new system.
Anybody have the same/similar experience? I'm considering installing 300 cpi cats to get a little back pressure and perhaps "convert/burn" the oil that's slippingby in my low back pressure system.
All the best from Horseshoe Bay!
Joe
1993 GTS - X-pipe, no cats, RMB
05-19-2012, 01:42 AM
#3
Rennlist Member
It would be worth doing compression and leakdown tests to ensure all is well with the motor. There probably isn't an issue, but they're checks that are easy to do to rule out ring/bore problems. Sloppy valve guides are also a possibility.
However ... GTS's burn oil to varying degrees, even with a healthy motor, and it doesn't surprise me that you're noticing this issue a little more with better engine breathing (and no cats). Rather than continue to burn the oil, you'd be better to invest in controlling the oil ingestion.
Greg Brown has an oil control solution discussed in this thread ... https://rennlist.com/forums/928-foru...8-engines.html
I'll be adding his system to my GTS soon ... others have devised their own solutions using pro vents and their own versions of breathing plumbing.
However ... GTS's burn oil to varying degrees, even with a healthy motor, and it doesn't surprise me that you're noticing this issue a little more with better engine breathing (and no cats). Rather than continue to burn the oil, you'd be better to invest in controlling the oil ingestion.
Greg Brown has an oil control solution discussed in this thread ... https://rennlist.com/forums/928-foru...8-engines.html
I'll be adding his system to my GTS soon ... others have devised their own solutions using pro vents and their own versions of breathing plumbing.
05-19-2012, 02:28 AM
#5
Rennlist Member
However ... GTS's burn oil to varying degrees, even with a healthy motor, and it doesn't surprise me that you're noticing this issue a little more with better engine breathing (and no cats). Rather than continue to burn the oil, you'd be better to invest in controlling the oil ingestion.
Greg Brown has an oil control solution discussed in this thread ... https://rennlist.com/forums/928-foru...8-engines.html
I'll be adding his system to my GTS soon ... others have devised their own solutions using pro vents and their own versions of breathing plumbing.
Greg Brown has an oil control solution discussed in this thread ... https://rennlist.com/forums/928-foru...8-engines.html
I'll be adding his system to my GTS soon ... others have devised their own solutions using pro vents and their own versions of breathing plumbing.
05-19-2012, 10:36 AM
#6
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Same issue on my GTS and another one here in DFW. We added some breather mods in the way of a provent and the issues was resolved. About to add a new breather system designed by Herman.
Made no difference with or without cats - puff of smoke was still there after the X pipe install.
Made no difference with or without cats - puff of smoke was still there after the X pipe install.
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928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission?
George Layton March 2014928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
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05-19-2012, 10:40 PM
#8
Rennlist Member
Yup, I'm the other one in the DFW area. Dave Robert's provent system was what finally cured the problem. I don't know if Dave is still producing these, but his system is the best solution.
05-20-2012, 12:14 AM
#10
Former Sponsor
Same issue on my GTS and another one here in DFW. We added some breather mods in the way of a provent and the issues was resolved. About to add a new breather system designed by Herman.
Made no difference with or without cats - puff of smoke was still there after the X pipe install.
Made no difference with or without cats - puff of smoke was still there after the X pipe install.
I had the "prototype" for this system on an engine at last year's Sharktoberfest...many pictures were taken of this system.....I've been testing and making modifications, since then.
I had multiple goals, not just keeping the intake system free of oil...I also wanted to reduce the crankcase pressure, so that the oil drains from the heads could return the oil to the crankcase faster, in order to "get" more oil to the oil pump pick-up. The 928 32 valve models, especially the GTS version, suffer greatly from inadequate crankcase ventilation, which adds to the oil build-up in the cylinder heads.
Hermann waited patiently for me to finish my testing, but finally gave up and made his own system. I simply don't release things until I've tested them and found that they work as they should....which seems to be rather unique, in the 928 world.
05-20-2012, 02:36 AM
#11
Rennlist Member
I also have a complete breather system (without the pump that I used to return oil from the heads, that some of you have seen) all ready to distribute, which has been thoughly tested on the stroker engines. Certainly my system doesn't look anything like Hermann's (I can't bring myself to using parts meant to be used on the water system inside my house on a motor vehicle....so my stuff is all "billet" aluminum pieces) and the "venting" arrangement is different. I'm going to ship the first systems, this next week.
05-20-2012, 11:04 AM
#13
Instructor
Thread Starter
I also have a complete breather system (without the pump that I used to return oil from the heads, that some of you have seen) all ready to distribute, which has been thoughly tested on the stroker engines. Certainly my system doesn't look anything like Hermann's (I can't bring myself to using parts meant to be used on the water system inside my house on a motor vehicle....so my stuff is all "billet" aluminum pieces) and the "venting" arrangement is different. I'm going to ship the first systems, this next week.
I had the "prototype" for this system on an engine at last year's Sharktoberfest...many pictures were taken of this system.....I've been testing and making modifications, since then.
I had multiple goals, not just keeping the intake system free of oil...I also wanted to reduce the crankcase pressure, so that the oil drains from the heads could return the oil to the crankcase faster, in order to "get" more oil to the oil pump pick-up. The 928 32 valve models, especially the GTS version, suffer greatly from inadequate crankcase ventilation, which adds to the oil build-up in the cylinder heads.
Hermann waited patiently for me to finish my testing, but finally gave up and made his own system. I simply don't release things until I've tested them and found that they work as they should....which seems to be rather unique, in the 928 world.
I had the "prototype" for this system on an engine at last year's Sharktoberfest...many pictures were taken of this system.....I've been testing and making modifications, since then.
I had multiple goals, not just keeping the intake system free of oil...I also wanted to reduce the crankcase pressure, so that the oil drains from the heads could return the oil to the crankcase faster, in order to "get" more oil to the oil pump pick-up. The 928 32 valve models, especially the GTS version, suffer greatly from inadequate crankcase ventilation, which adds to the oil build-up in the cylinder heads.
Hermann waited patiently for me to finish my testing, but finally gave up and made his own system. I simply don't release things until I've tested them and found that they work as they should....which seems to be rather unique, in the 928 world.
I would be very much interested in learning more about the system you have developed. Will you be posting info on product description, system cost, etc?
All the best from Horseshoe Bay,
Joe
05-23-2012, 02:16 AM
#14
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just wanting to bring this back to the top so it doesn't get lost in the shuffle so Greg has an opportunity to possibly post a picture or two/or not, where to order, maybe a price. i am mostly interested in where to send my money.
05-23-2012, 03:02 AM
#15
Former Sponsor
Sorry. Posted and moved on to "another" project.
System cost will be $1295. Not cheap, but very nice and looks like it "belongs" there....like it came from the Porsche factory, to fix ventilation problems, in 1996.
I'm still waiting for some clamps, I'm missing, to come in, from Germany, to ship. (And then these have to go out to be plated gold.) I know that sounds insane, but they have to be "Norma" to look totally factory. Almost all of the replacement hoses have 928 part numbers on them, so people that "don't instantly know" it doesn't belong there might never figure it out! All of the "adaptors" I've hand "wittled" out of billet aluminum, welded them together and then "wittled" on them some more....so they look like they are one piece. There's a line that runs under the driver's injector rail that I hand made out of stainless steel. It's stupid nice stuff.
Being "stupid ****" isn't as great as you might imagine. I can literally make anything, but money. Rob Edwards walked in one day, while I was "hand wittling" on some aluminum pieces and laughed very hard...asking if each fitting was sold at the local jewelry store....he has pictures....ask him to post them.
And on "top" of the stupid price is the fact that you need to remove the valve covers....and the intake system....unless you are a stinking Ninja and can get that front filler neck off and "route" some new hoses under the manifold, with it on.
This is not a "simple" system....because the problem isn't simple. Porsche changed the ventilation system for the 32 valve engines about 6 or 7 times....and never did figure it out.
The GTS model ventilation systems (yes, there are two versions) is pathetic. I have no idea what the hell they were thinking or doing....it's like the engineers came from the local grammar school!
Oh yeah....and I only made up 6 sets of parts.....and only a couple aren't "spoken" for...by really patient clients! But I have patterns and will make more...
System cost will be $1295. Not cheap, but very nice and looks like it "belongs" there....like it came from the Porsche factory, to fix ventilation problems, in 1996.
I'm still waiting for some clamps, I'm missing, to come in, from Germany, to ship. (And then these have to go out to be plated gold.) I know that sounds insane, but they have to be "Norma" to look totally factory. Almost all of the replacement hoses have 928 part numbers on them, so people that "don't instantly know" it doesn't belong there might never figure it out! All of the "adaptors" I've hand "wittled" out of billet aluminum, welded them together and then "wittled" on them some more....so they look like they are one piece. There's a line that runs under the driver's injector rail that I hand made out of stainless steel. It's stupid nice stuff.
Being "stupid ****" isn't as great as you might imagine. I can literally make anything, but money. Rob Edwards walked in one day, while I was "hand wittling" on some aluminum pieces and laughed very hard...asking if each fitting was sold at the local jewelry store....he has pictures....ask him to post them.
And on "top" of the stupid price is the fact that you need to remove the valve covers....and the intake system....unless you are a stinking Ninja and can get that front filler neck off and "route" some new hoses under the manifold, with it on.
This is not a "simple" system....because the problem isn't simple. Porsche changed the ventilation system for the 32 valve engines about 6 or 7 times....and never did figure it out.
The GTS model ventilation systems (yes, there are two versions) is pathetic. I have no idea what the hell they were thinking or doing....it's like the engineers came from the local grammar school!
Oh yeah....and I only made up 6 sets of parts.....and only a couple aren't "spoken" for...by really patient clients! But I have patterns and will make more...