Failed SAI flush. No longer impressed, or amused with Porsche.
#32
Instructor
Join Date: Nov 2006
Location: Connecticut
Posts: 119
Likes: 0
Received 0 Likes
on
0 Posts
I understand the SAI problem but was surprised to see the DIY a few days ago detail how the port ran thru the cam carrier and head to outlet behind the exhaust port.
I seem to remember my 930 had air injection and a pump that routed air to the exhaust manifold. Seems like life was easier then, there were no internal passages. I actually can't see what is wrong with that set up either.
From what I have seen it is a common practice for the auto manufacturers and ecu producers to engage the air pump when the motor is cold between x and y temps and then look to the oxygen sensors for a change in the a/f ratio. Realizing that the factory has many well qualified engineers to run solutions and prove them and that is why the cars work well from the factory.. they are not beyond reproach (remember how many versions there are of the cooling blower fan!) and why not install a couple or air ports upstream of the cats, let the oxygen go in and tickle the lambdas and forget about the ports in the head that look like misery to clean out. If I ever have this issue with my 993 T, I would like to weld on ports near the 3-1 exhaust junction and insert the air, it looks like a lot less work and can anyone tell me for a fact that this scheme will not work.
Perhaps the combined wisdom of the rennlist can produce such a "kit" with a pair of capillaries and ports etc. Seems like life could be simpler .. no???
Danny Shapiro
993 TT '96 with 35K miles pulls and runs like a freight train on rails and loving my new hds and eibach..even though the dealer soaked me for an alignment... now I remember why I haven't bought services there for 25 years...
I seem to remember my 930 had air injection and a pump that routed air to the exhaust manifold. Seems like life was easier then, there were no internal passages. I actually can't see what is wrong with that set up either.
From what I have seen it is a common practice for the auto manufacturers and ecu producers to engage the air pump when the motor is cold between x and y temps and then look to the oxygen sensors for a change in the a/f ratio. Realizing that the factory has many well qualified engineers to run solutions and prove them and that is why the cars work well from the factory.. they are not beyond reproach (remember how many versions there are of the cooling blower fan!) and why not install a couple or air ports upstream of the cats, let the oxygen go in and tickle the lambdas and forget about the ports in the head that look like misery to clean out. If I ever have this issue with my 993 T, I would like to weld on ports near the 3-1 exhaust junction and insert the air, it looks like a lot less work and can anyone tell me for a fact that this scheme will not work.
Perhaps the combined wisdom of the rennlist can produce such a "kit" with a pair of capillaries and ports etc. Seems like life could be simpler .. no???
Danny Shapiro
993 TT '96 with 35K miles pulls and runs like a freight train on rails and loving my new hds and eibach..even though the dealer soaked me for an alignment... now I remember why I haven't bought services there for 25 years...
#33
Burning Brakes
Thread Starter
my car uses quite a bit of oil, actually. i estimate going through 1 quart every 750 miles. however, i believe porsche considers this acceptable. it is on the low end, for sure. any LESS than that is definately no good.
#34
Three Wheelin'
Join Date: May 2005
Location: Orange County, So Cal
Posts: 1,367
Likes: 0
Received 4 Likes
on
3 Posts
Originally Posted by Traffic53
my car uses quite a bit of oil, actually. i estimate going through 1 quart every 750 miles. however, i believe porsche considers this acceptable. it is on the low end, for sure. any LESS than that is definately no good.
Sorry to hear of your problems. As painful as it likely sounds, with your stated oil consumption it seems like your shop only tried to address the symptom rather than dealing with the cause (worn guides). I've heard horror stories about clogged ports and the inability to get them unplugged, and ultimately the only sure-fire solution is ream them while the engine is apart.
Maybe your shop would credit you all of their labor for the flush and let you put it towards a top end rebuild? Sounds like an inevitability at some point in the near future anyway.
As others have stated, I went through the "rage phase" with my car but came out the other end (the new top end!) really loving her... you can't know the peace of mind that comes from biting the bullet and getting it done until you experience it.
Probably not the greatest solution in your mind at this point, but just my $.02.
Good luck.
#35
Addict
Rennlist Member
Rennlist Member
I may or may not do the top end on my new 97 ... and if I do, I will probably reroute the air to the exhaust. I'll make sure and have some photos of it to post.
#36
Technical Guru
Rennlist Member
Rennlist Member
Originally Posted by 98993c2s
eliminating the CEL and OBDII codes so the cars can pass emissions,
#37
Rennlist Member
Originally Posted by 98993c2s
Either a physical port bypass (there was a thread about that recently) or a device to fool the computer...
I agree 100%.
By the way, this problem is not limited to Porsche. BMW has the same issue with its M5.
However, my understanding is that, at least for Porsche, the O2 sensor detects the drop in oxygen level when the air is not injected through the ports into the exhaust stream, so why not just add a bypass just upstream of the sensor and divert some additional air there. I don't have the problem with my 96 (knock on wood) but that is the exact path I will pursue before I even think about opening the engine to unplug some useless holes.
#38
Addict
Rennlist Member
Rennlist Member
I read through the Massachusetts emissions laws; it specifically states that "temporary repairs" to the system to improve its performance are okay as long as they are not messing with the OBD2 computer system or sensors. I would interpret that as saying it's okay to "re-engineer" the system as long as it's doing what it's supposed to do ... i.e., getting more oxygen to the cats to heat them quicker, which is what my understanding of the SAI system is. I would think that would not be illegal; putting a circuit board to fool the OBD2 system about the condition of the oxygen sensor would be.
#39
Boost Junkie
Lifetime Rennlist
Member
Lifetime Rennlist
Member
Join Date: Jan 2004
Location: Plymouth MN and Scottsdale AZ
Posts: 2,536
Received 43 Likes
on
35 Posts
Originally Posted by JasonAndreas
The problem with a company creating a product or your mechanic installing a workaround is that the EPA enforcement division will send them a letter that says, "Section 203(a)(3)(A) of the Clean Air Act states, that for any person to remove or render inoperative any device or element of design installed on or in a motor vehicle or motor vehicle engine in compliance with regulations under this title prior to its sale and delivery to the ultimate purchaser, or for any person knowingly to remove or render inoperative any such device or element of design after such sale and delivery to the ultimate purchaser is prohibited." And if you don't comply they will close your business down.
#40
Rennlist Member
Originally Posted by vjd3
I read through the Massachusetts emissions laws; it specifically states that "temporary repairs" to the system to improve its performance are okay as long as they are not messing with the OBD2 computer system or sensors. I would interpret that as saying it's okay to "re-engineer" the system as long as it's doing what it's supposed to do ... i.e., getting more oxygen to the cats to heat them quicker, which is what my understanding of the SAI system is. I would think that would not be illegal; putting a circuit board to fool the OBD2 system about the condition of the oxygen sensor would be.
#41
Race Director
Originally Posted by Traffic53
my car uses quite a bit of oil, actually. i estimate going through 1 quart every 750 miles. however, i believe porsche considers this acceptable. it is on the low end, for sure. any LESS than that is definately no good.
Converts to apx. 1qt per 625 mi.
#43
Addict
Rennlist Member
Rennlist Member
I could strap a Flux Capacitor to my engine and it would pass a visual check here on Cape Cod. I have no idea what kind of people you have inspecting your cars where you live but around here they all hate "The Man".
#44
Three Wheelin'
Join Date: Dec 2002
Location: Tampa
Posts: 1,367
Likes: 0
Received 0 Likes
on
0 Posts
Interesting to hear about the lack of problems with the Euro cars. Adrian recently sent out a lengthy missive on the e-mail list on this topic and one thing he mentioned was the difference between US il and Euro oil.
Adrian; would you care to elaborate??
Jack
Adrian; would you care to elaborate??
Jack
#45
Addict
Rennlist Member
Rennlist Member
Join Date: Jul 2003
Location: Austin
Posts: 388
Likes: 0
Received 0 Likes
on
0 Posts
There are plenty of companies that produce such products and I haven't heard of any of them being shut down. 02 simulators, cat bypasses, etc.
And the way this is worded, I don't see anything that prevents a company from producing such a product; technically, the wording only applies to 'a person' who does the work on the car.
And the way this is worded, I don't see anything that prevents a company from producing such a product; technically, the wording only applies to 'a person' who does the work on the car.
Originally Posted by JasonAndreas
The problem with a company creating a product or your mechanic installing a workaround is that the EPA enforcement division will send them a letter that says, "Section 203(a)(3)(A) of the Clean Air Act states, that for any person to remove or render inoperative any device or element of design installed on or in a motor vehicle or motor vehicle engine in compliance with regulations under this title prior to its sale and delivery to the ultimate purchaser, or for any person knowingly to remove or render inoperative any such device or element of design after such sale and delivery to the ultimate purchaser is prohibited." And if you don't comply they will close your business down.