Exhaust clearance issues - what are my minimum gaps?

[sigtauenus]

I have the magnaflow 2.5" exhaust mocked up.  Right now it has clamps holding it in position, and I'm going to take it to a shop to get welded up except for the front clamps on the muffler (for transmission access). 

Right side spring doesn't have much room with centering the tip in the valence opening.  Actual placement will be a little higher in the opening, but I was holding the tip up and trying to take the picture, so it didn't work the way I wanted.


Driver side rubber brake line.  I think if I loosen the clamp and rotate the pipe I can get a little more clearance.


Driver side shock - looks ok, but kind of close


Mufflers

(I still need to touch up the rear housing from my old jack, I have since bought a new one with a rubber pad on the saddle.



The x-pipe/intermediate pipes are in line with the headers and then rise as they go back.  Does that angle look right or is that all hanging too low?
(Before Dave asks, that clamp on the piece that bolts to the header is holding a butt-seam together for now - only needs to go about 1.4 miles to the shop, might even tow it there)

[buening]

That brake hose would make me nervous.  Mine was a bit close and I was able to bend the bracket so that the brake block is closer to the axle tube.  I only had to do that when I moved the engine back.  I wouldn't think yours should be that close with the engine in the stock location.  Are you sure you have the exhaust pipe fully seated in the back of the muffler?  If so, I'd tell the exhaust shop (or you can do this yourself) to cut an inch or two off the end of the pipe so that you don't have these clearance problems over the axle.  I had to do this to mine due to moving the motor back.

[sigtauenus]

Great idea.  You're right, the pipe is not seated fully on the muffler because I'm using clamps, and if I did seat it fully, I couldn't be able to compress the clamp enough to hold.  I know because I ruined 2 clamps so far trying before I figured out the clamp needs to ride only on the slits in the pipe, which means the pipe needs to be about 1/2" or so out from being tight against the muffler.

When I have it welded up, I'll tell the shop to push it tight. 

I'll also be sure to emphasize that its currently only mocked up, and they need to level the mufflers (they are slightly twisted right now), etc, before they start welding.

[silverblueBP]

By all means, get that brake line away from the pipe...as far as possible!

[sigtauenus]

You know, looking at those pics again, it occurred to me that the underside of my car will never again be as clean as it is right now once I start driving it. 

[buening]

Yeah I had mine all prettied up when I finished the underside, then drove the car 10k+ miles, then decided to do my transmission swap.  Its amazing how cruddy things get under there, then again I had a leaking FMX that sprayed everything under there.   :po

[Fast68back]

Trying to picture mine and how low it hangs, I dont think mine is lower than the front subframe. I know its visible in my signature pic...

This is a more eye level shot

[sigtauenus]

Rick, I think that's based on your headers.  I'm limited by how low the collectors are sitting and have no adjustment there.  I'd like to have it higher but that would mean buying new headers.

[Fast68back]

Rick, I think that's based on your headers.  I'm limited by how low the collectors are sitting and have no adjustment there.  I'd like to have it higher but that would mean buying new headers.

Your correct, I have JBA shorties and JBA H pipe dumping into whats left of the stainless magnaflow kit

[2ndgen]

That rear brake line is an accident waiting to happen. :scar


When I get back to my car this weekend I'll snap some pictures of my setup - it is a 69 using the Magnaflow 2.5 inch kit with pypes split extensions like yours with a dual exhaust rear valence. From the mufflers back the system is pretty much out of the box; a lot of work was done forward of the mufflers to fit with a TCP cross brace. The system is up in the driveshaft tunnel but can not accomodate the x-pipe; however your system is hanging way too low...

-Rory

[sigtauenus]

I'm stuck at the collectors with how low it hangs, but I'll ask the exhaust shop if they can cut the connection at more of an angle and get the x-pipe up higher.  I still have enough slop in the system (slip fittings shoved way in) that they should be able to do that.

I'll be sure to tell them to rotate the pipe near the brake line tomorrow too.

[daveSanborn]

This......







.... is WAY TOO LOW for a daily driver.  Even though you can't get your collectors higher, the muffler shop should be able to put some slight bends in your exhaust pipes to get everything from the collector rearward a LOT higher than is currently pictured.  This way, when you pull off the road into McDonald's you'll only drag 6" of collector pipe on the pavement instead of 4' of collector/exhaust pipe.

[sigtauenus]

Its at the shop now, that's what I asked them to do, well move it higher, figured they'd figure how to do it.

[buening]

What headers are you using?

[2ndgen]

.... is WAY TOO LOW

Dave - is there an echo in here?

Its at the shop now, that's what I asked them to do, well move it higher, figured they'd figure how to do it.

If you don't mind, would you post a follow up on the number of hours of labor you were charged for the install... I'm looking for a little ammunition.

-Rory

[buening]

You may find that they will be limited on how high they can tuck it up, because the pipes between the Xpipe and muffler flare upwards just before the muffler (to tuck the muffler up higher). You will also be bending a mandrell bent pipe, which may likely crush it at the bends.  I will see if I can take a pic of mine installed, but they are pretty similar but likely higher than what your last pic shows.  Your header collectors do seem really low. 

If it were me, I'd have them remove the pipe between the Xpipe and the collector reducer and bend up a new section to raise the Xpipe higher up.  Another option would be to try cutting the reducer and head pipe at an angle and welding them together, instead of making a new head pipe as I previously mentioned. My shop did something pretty similar although mine didn't need anything that extreme since my headers were actually tucked up too high.

[sigtauenus]

Dynomax.  Got them used from a friend.  I took them because they are almost new, ceramic coated, and can't beat the price.

Just went back by the shop, they had the car on the lift and were about to start.  They can get the tips where I want them, but if they move the pipe away from the brake line they won't be able to put the tip on the driver side centered in the notch.  The easiest fix is for me to do some tweaking to the brake lines and move the bracket to the left, might have to cut and reflare the line to the driver cylinder, but I can do that.

As for how low they hang, I think I'm stuck.  The guy said with the mandrel bent kit, there's no room for them to make any bends without rebuilding everything from the collector back to the muffler, ie, trashing the x-pipe and intermediate pipes in the process.  They could technically force the bend, but then that defeats the purpose of the mandrel bent system.  I remember at least one other person being told that by an exhaust shop that it would have been easier for them to just build the front of the exhaust from scratch than it was to make the Magnaflow kit fit their headers.  

I'll see how it goes, if its a problem, I'll evaluate what the best fix is, ie, changing out the headers to something that doesn't hang as low or rebuilding the x-pipe and intermediate pipes, or both.  

[sigtauenus]

If you don't mind, would you post a follow up on the number of hours of labor you were charged for the install...

Estimate was 1.5 hours.

[daveSanborn]

might have to cut and reflare the line to the driver cylinder, but I can do that.

It's not the connection point between the hard line and rubber line that's the close interference with the exhaust pipe, it's that the soft rubber line is running "straight" down to the rear axle.  To "bend" the soft rubber line away from the exhaust pipe, get a piece of coat hangar, cut it to fit the length of the rubber line, tape (or otherwise affix the coat hangar to the soft rubber line) and then "bend" the rubber line away from the exhaust pipe.  The coat hangar/soft line should retain the shape of whatever bend you create.


Understand that if you change out your headers "down the road", you're probably going to have to re-do a large portion of the exhaust pipe work you're getting done today.

[tarafied1]

my old headers would drag on everything, I couldn't run over an ant with them scraping his antenna!

with FPA shortie headers, they tuck up nicely and I have scrapped the oil pan now and still not dragged the exhaust.

but like Dave said, it requires major changes in the system.

[sigtauenus]

It's not the connection point between the hard line and rubber line that's the close interference with the exhaust pipe, it's that the soft rubber line is running "straight" down to the rear axle.  To "bend" the soft rubber line away from the exhaust pipe, get a piece of coat hangar, cut it to fit the length of the rubber line, tape (or otherwise affix the coat hangar to the soft rubber line) and then "bend" the rubber line away from the exhaust pipe.  The coat hangar/soft line should retain the shape of whatever bend you create.

Great idea, that would be a lot easier to do!

Understand that if you change out your headers "down the road", you're probably going to have to re-do a large portion of the exhaust pipe work you're getting done today.

Got it, and I do understand that.  If I'm soon driving this thing enough for that to annoy me enough to spend the cash to redo the exhaust, I'll consider that a good thing.   :lol

[buening]

IMO, if you change headers the only thing that would have to be modified is the welded collector reducer and head pipe that slides into the xpipe. If you get lucky, the header collector flanges will end up in a similar location and the head pipe can be pulled out (or cut down) of the Xpipe slightly to fill the gap.  The weld at the reducer-to-headpipe may need broke and rewelded depending on the new exhaust angle, in order for your header collector gaskets to seal correctly.

If you raise the collector reducer 1" due to higher fitting headers, the system essentially pivots on the tailpipe hangers.  Your tailpipe will go farther down in the valance exhaust openings, but it shouldn't be enough to really notice.  I dropped and moved my motor back all after the exhaust was finished and all I had to do was trim a bit off the end of the pipe before the mufflers. 

[sigtauenus]

Pics also posted in my other topic.









I need to get some pics of the how the tips look for you guys.  They are farther out than some others (ok, Craig's), but I like where they are, he put them pretty much right on where I told him to.

Mufflers are clamped on both ends.  The guy who welded it up said he thought it would be easier to get the system apart with both ends clamped if that's why I wanted the front clamped.  After the discussion above about moving the front around if I have issues with it scraping, it turns out to be a great call since I may need to slide the back around slightly if it does in fact cantilever raising the front.