Lets play some "Tell me what you see."
07-29-2012, 07:24 PM
#1
Three Wheelin'
Thread Starter
Lets play some "Tell me what you see."
I've only had my 964 for about two months. A few days ago I set out to put on a cat bypass that came with the car, but things didn't go well since I suppose the muffler bypass was fabricated and as a result is too short. I also noticed a few other things.
So I will say my assumptions and I would like to hear your opinions.
My Assumptions
1- Because of the primary muffler bypass, which looks to be a welded on straight pipe, the cat bypass pipe I have is too short to fit it. It seems the OEM cat was also a bit fabricated to fit the bypass pipe as well since you can see a lot of welding done by the flange.
2-It seems that my valve covers are a bit moist, but only on the left side of the car. From searching it seems sometimes the valve cover lining fades and this happens?
3- There is this other "moist" area not too far from the valve covers, anything that really needs taking care of?
4- What does this switch in the trunk belong to?
5- If I get the cup pipe, it will replace the secondary muffler?
Now for the pictures:
So I will say my assumptions and I would like to hear your opinions.
My Assumptions
1- Because of the primary muffler bypass, which looks to be a welded on straight pipe, the cat bypass pipe I have is too short to fit it. It seems the OEM cat was also a bit fabricated to fit the bypass pipe as well since you can see a lot of welding done by the flange.
2-It seems that my valve covers are a bit moist, but only on the left side of the car. From searching it seems sometimes the valve cover lining fades and this happens?
3- There is this other "moist" area not too far from the valve covers, anything that really needs taking care of?
4- What does this switch in the trunk belong to?
5- If I get the cup pipe, it will replace the secondary muffler?
Now for the pictures:
07-29-2012, 07:52 PM
#2
Nordschleife Master
That straight pipe = cup pipe.
Looks like the bypass is shorter than the cat. This is your problem. They should be the same size.
Search for a post by user Babalouie as I believe he also experienced a too short cat bypass and had to have it modified to make it longer.
If you want to get rid of the secondary then you want a G-pipe.
At that point you will have a straight through exhaust and will be very loud. It's a decision of by-passing the primary or the secondary, but not both (unless you like a loud car).
Wetness under valve covers seems reasonable. Maybe snugging up the 10mm nuts will cure it, but remember they're only suppose to be tightened to 7ft/lbs.
When was the last time the valves were done? Perhaps they tried reusing the old gaskets.
The wet spot by the timing chain area is possibly the timing chain covers. Also likely not a big deal.
Is oil dripping onto your driveway?
Looks like the bypass is shorter than the cat. This is your problem. They should be the same size.
Search for a post by user Babalouie as I believe he also experienced a too short cat bypass and had to have it modified to make it longer.
If you want to get rid of the secondary then you want a G-pipe.
At that point you will have a straight through exhaust and will be very loud. It's a decision of by-passing the primary or the secondary, but not both (unless you like a loud car).
Wetness under valve covers seems reasonable. Maybe snugging up the 10mm nuts will cure it, but remember they're only suppose to be tightened to 7ft/lbs.
When was the last time the valves were done? Perhaps they tried reusing the old gaskets.
The wet spot by the timing chain area is possibly the timing chain covers. Also likely not a big deal.
Is oil dripping onto your driveway?
07-29-2012, 08:23 PM
#4
Nordschleife Master
Babalouie's thread, look toward the bottom of page 10.
https://rennlist.com/rennforums/show...648528&page=10
https://rennlist.com/rennforums/show...648528&page=10
07-29-2012, 09:15 PM
#5
Rennlist Member
Your muffler bracket is bend way out of shape, therefore your catbypass will not reach the primary bypass, also the ends on your PB pipe should be the same, no flange as on the left side.
I suggest you take the PB pipe off as well as the muffler (bypass) bracket, straighten the bracket and reinstall, you will then have to fix the BP on the left side so it will match the Catbypass, I.E. make it the same as the right side.
Hope this makes sense.
PS. Your catbypass is the right length, it's the cat which has been modified ( flange added ), that is too long.
I suggest you take the PB pipe off as well as the muffler (bypass) bracket, straighten the bracket and reinstall, you will then have to fix the BP on the left side so it will match the Catbypass, I.E. make it the same as the right side.
Hope this makes sense.
PS. Your catbypass is the right length, it's the cat which has been modified ( flange added ), that is too long.
07-29-2012, 10:17 PM
#7
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1) yes, your cat has been modified with a flange. Your cup pipe--primary bypass is custom made with a flange vs. a flared end like the cat bypass which is OE.
2) yes, it is common for the valve cover gaskets to leak. Your leak is minor. I would address on the next valve adjustment.
3) It appears to be your chain cover gasket. It also appears to minor and can be addressed at a later date.
4) No pic of the switch
5) No, the G pipe replaces the secondary muffler. You currently have a cup pipe installed.
Options: (1) replace your custom made cup pipe with a standard flared cup pipe and install the cat bypass.
(2) Install cat bypass. Find a used primary muffler to match your cat bypass. Remove secondary muffler and install a G pipe.
(3) leave as is and do not install your cat bypass.
Removing both mufflers is too loud.
2) yes, it is common for the valve cover gaskets to leak. Your leak is minor. I would address on the next valve adjustment.
3) It appears to be your chain cover gasket. It also appears to minor and can be addressed at a later date.
4) No pic of the switch
5) No, the G pipe replaces the secondary muffler. You currently have a cup pipe installed.
Options: (1) replace your custom made cup pipe with a standard flared cup pipe and install the cat bypass.
(2) Install cat bypass. Find a used primary muffler to match your cat bypass. Remove secondary muffler and install a G pipe.
(3) leave as is and do not install your cat bypass.
Removing both mufflers is too loud.
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07-29-2012, 10:24 PM
#8
Your muffler bracket is bend way out of shape, therefore your catbypass will not reach the primary bypass, also the ends on your PB pipe should be the same, no flange as on the left side.
I suggest you take the PB pipe off as well as the muffler (bypass) bracket, straighten the bracket and reinstall, you will then have to fix the BP on the left side so it will match the Catbypass, I.E. make it the same as the right side.
Hope this makes sense.
PS. Your catbypass is the right length, it's the cat which has been modified ( flange added ), that is too long.
I suggest you take the PB pipe off as well as the muffler (bypass) bracket, straighten the bracket and reinstall, you will then have to fix the BP on the left side so it will match the Catbypass, I.E. make it the same as the right side.
Hope this makes sense.
PS. Your catbypass is the right length, it's the cat which has been modified ( flange added ), that is too long.
As for 2/3 I have no information. Do you have a picture of the switch (4)?
07-29-2012, 10:57 PM
#9
Three Wheelin'
Thread Starter
Thanks for the help guys, I had no real intention of removing the secondary muffler, just trying to get the terminology straight among things. The muffler bracket is the one that is in the second picture correct? I'm going to try to consider the options to take now, preferably to be in the cheaper matter or which sound I like best. As for leak, I had a drop about a week ago, which kind of made me take a look. The engine had a rebuild 10k miles ago and there had been no "documented" valve adjustment done, so I want to try and do it myself within the next month.
As for the trunk plug, forgot to add the picture.
As for the trunk plug, forgot to add the picture.
07-29-2012, 11:23 PM
#11
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Your muffler bracket is fine. It was bent so it would be close enough to the custom made cup pipe to get a clamp on the pipe.
A OE cup pipe has a bracket on the back which makes it the same distance as the primary muffler at the attachment point.
Your least expensive route would be to have a muffler shop add a flared end on the cat side of the cup pipe.
A OE cup pipe has a bracket on the back which makes it the same distance as the primary muffler at the attachment point.
Your least expensive route would be to have a muffler shop add a flared end on the cat side of the cup pipe.
07-29-2012, 11:32 PM
#12
Three Wheelin'
Thread Starter
Babalouie's thread, look toward the bottom of page 10.
https://rennlist.com/rennforums/show...648528&page=10
https://rennlist.com/rennforums/show...648528&page=10
07-30-2012, 12:32 AM
#14
Oh I see, thanks for the clear up. Another thing is that as you can see from the first picture is that my cat bypass pipe has no brackets to mount to the heatshield, also in that thread there seems to be some kind of shield "defending" the valve covers and I don't seem to have that piece either. Would heat be such a concern?
https://rennlist.com/forums/964-foru...-mechanic.html
07-30-2012, 12:35 AM
#15
Search the forum and you will find several posts that the Cat Bypass doesn't need the heat shield as it doesn't hold heat like the cat does. Fab Speed has posted this as well. I do note that the Schnell cat bypass does look like it has brackets for the shield though. BTW I have a Fab Speed cat bypass and a Schnell primary muffler bypass (cup pipe). I put the primary bypass on yesterday and I am very happy with the sound. Not too loud no drone. Maybe a small perf increase. The fit was good with the stock band clamps.