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  #46  
Old March 30th, 2012, 14:00
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TRCM TRCM is offline
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Re: Joel's multipurpose XJ build (rocks/boulevard)

I figured it out cuz my rpm @ 60 was 2000-2100, and it should have been around 1650-1700.

IM me your email addy, and I will send you the link I used. I can't post it here, as it is on a sight that has caused problems due to copyright info I think.
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  #47  
Old March 30th, 2012, 14:06
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Re: Joel's multipurpose XJ build (rocks/boulevard)

run this as your trackbar:
http://claytonoffroad.com/product_in...697e765fa45ef3

double shear and a johnny joint at the frame.

also, you probably want to put a bend in the body of the pitman arm TRE...looks to be almost maxed out at ride height.
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  #48  
Old March 30th, 2012, 14:34
troy5118 troy5118 is offline
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Re: Joel's multipurpose XJ build (rocks/boulevard)

I recently changed my exhaust out and wanted to do a backpressure test before and after to see what the effect was but ran out of time. I couldn't believe that the smashed section of 2" tube was needed. There should be adequate back pressure from the exhaust by the time it makes all the turns to get out the back and has to travel thru a cat and muffler.

I cut off the 2" section of the front pipe and tig welded mandrel 2 1/2" up to the header. The back half of the pipe was still in great shape so I reused it. To finish it I added a cat, Magnaflow muffler and mandrel tailpipe from performance curve. It turned out very nice and runs great.

(I had some pics on here but I didn't want to clog up your thread, let me know if you want something to look at)

Last edited by troy5118; March 30th, 2012 at 14:47. Reason: Removed pics
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  #49  
Old March 30th, 2012, 15:06
frijolee frijolee is offline
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Re: Joel's multipurpose XJ build (rocks/boulevard)

Hey Troy,

I don't mind a little clutter, I did come in here asking for advice and commentary and that inherently means this thread will wander a bit. How about a good teaser pic of your exhaust build and a link to the remainder?

-Joel
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  #50  
Old March 30th, 2012, 20:00
frijolee frijolee is offline
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Re: Joel's multipurpose XJ build (rocks/boulevard)

Exhaust (in with the new):

When I went looking for exhausts I discovered there a lot of ways I donít yet belong in the Jeep world. Thereís a lot of nice work out there but it seems like among the hardcore wheelers exhausts are treated as sacrificial and some of the jerry rigging I ran across blows my mind. I found several old threads where folks were talking about how plumberís tape was more than sufficient to serve as a hanger cause it wasnít going to matter long anyways. Iím just not wired to think that way. Give me a couple years on the trails and weíll see my opinion changes.

In the meantime, I built my exhaust using piecewise using all 2.5Ē mandrel-bent 304L stainless. It was a good excuse to buy a band saw as well which suddenly I seem to use on everything.
http://www.amazon.com/Jet-414458-HVBS-56M-Horizontal-Vertical/dp/B00004T9KU/ref=sr_1_2?ie=UTF8&qid=1333058072&sr=8-2
The band saw came in a 125 lb box via freight and a scheduled delivery time yet had FREE super saver shipping (yeah Amazon!). I picked up a couple bi-metal blades in various tooth pitches and some stick cutting lube and Iíve been impressed with what itíll get through

I then set out with the intent to route and/or armor my exhaust such that itíll never get screwed up in the first place. Iím hoping it outlasts the vehicle.

Cat: Mangnaflow 45036 (the California legal version costs more for no apparent reason)
http://www.magnaflow.com/02catalytic_converters/02product/displayuniversal.asp?universal=45036

Muffler: Spintech Sportsman XLF 3332, 3Ē tall case (yes, I sprung for stainless, Iím a geek)
http://www.spintechmufflers.com/mufflers/street-mufflers/low-profile-street-mufflers/3000-xlf-round-sportsman-street-low-profile-/sportsman-street-3332xlf-2a-c-2a-s/prod_417.html

Note, I debated going with the Spintech ďCruiserĒ series where the muffler case is only 2 1/4" tall but after talking with the sales rep they said mine flows a bit better, runs a bit quieter, and I canít really use the clearance since my cat is about 4Ē thick anyways.

Flexpipe:
2.5 x 6Ē with interlocked core (smoother flow) for some guy on ebay. Got the remainder of the mandrel bend tubing on ebay as well (0.062 wall) plus some stainless 3/8Ē pencil rod for hangers.

Thereís also a 2.5Ē V-band between each component so itís all serviceable as well. When I went to pull out the old exhaust I found the u-clamps had crushed the tubes to the point that I had to cut everything apart with my friend the angle grinder. No bueno.

The good news is that the Jeep feels a little stronger with the new setup so Iím happy. Now that I think about it, Iím not sure Iíve recalculated fuel economy since I built this. I should probably check that out.

It came out nice, if I do say so myself. I think I gained about 4Ē of ground clearance doing this. (The before pictures a few posts above).




















I built in an extra bung for wideband O2 tuning and I splurged on a fancy tailpipe exhaust hanger (again ditching the rusty *ish)
http://www.deedsengineering.com/EXHAUST_HANGERS.html



One recommendation if anyone else wants to try this hanger. The bushing it comes with is not nearly compliant enough. It blew out immediately the first time the exhaust got hot when the piping grew via thermal expansion. I ended up redesigning the joint with a shoulder bolt and an oil-lite bushing so it acts like itís on a linear bearing and grows about 3/8Ē fore/aft as it gets hot.
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  #51  
Old March 30th, 2012, 20:01
frijolee frijolee is offline
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Re: Joel's multipurpose XJ build (rocks/boulevard)

By the way, I drove this without the tail section one time on the freeway. Remind me never to run a turn down. The droning on the freeway was un-livable. So far as I can tell, dumping the exhaust under the car just reflects the sound waves off the ground straight back into the bottom of the vehicle.

If anyone is looking for a cheap exhaust I was momentarily temped by the low buck route from the DynoMax catback
https://www.google.com/search?q=xj+exhaust+dynomax&sourceid=ie7&rls=com.m icrosoft:en-US:IE-SearchBox&ie=&oe=#hl=en&rls=com.microsoft:en-US%3AIE-SearchBox&tbm=shop&sclient=psy-ab&q=xj+cat+back+dynomax&oq=xj+cat+back+dynomax&aq =f&aqi=&aql=&gs_l=serp.3...7862l8876l2l9094l8l8l0l 0l0l5l234l1449l0j6j2l8l0.frgbld.&psj=1&bav=on.2,or .r_gc.r_pw.r_qf.,cf.osb&fp=25828f9a7ae54771&biw=95 2&bih=763

That said, I just couldn’t bring myself to throw those u-clamps back on the Jeep. I think I spent 3x as much in materials for my version, but it’s exactly how I wanted it so I’ll deal.

Underbody armor is next (this is the part where I kind of went off the deep end).
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  #52  
Old March 31st, 2012, 13:08
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Tacedaddy Tacedaddy is offline
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Re: Joel's multipurpose XJ build (rocks/boulevard)

yours looks alot better than mine.. i should have went with stainless LOL
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  #53  
Old March 31st, 2012, 14:33
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Vanimal Vanimal is offline
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Re: Joel's multipurpose XJ build (rocks/boulevard)

stainless is too rich for my blood. i dont think i've ever had a vehicle with an exhaust that rotted out in socal, so it doesnt seem worth it. my van is 21 years old with 287k and it's still solid and original. the jeep has 217k and is 20 years old, original except for a flowmaster muffler welded to the stock original pipes.
back east was another story....
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  #54  
Old March 31st, 2012, 15:38
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Re: Joel's multipurpose XJ build (rocks/boulevard)

that exhaust LOOKS real bitchin. but from the link you posted that is not a legal cat. jan of 2012 new calif laws states that the cat must be vehicle specific. and the one you listed is for a 96-97. i tried looking up a 99 but couldnt find a listing. but the 98 was different from the one you used. so you may find some issue with smog cert. especially when they see all that nice new stainless exhaust. when they look and see new exhaust work, they are supposed to (by law) run the numbers off the cat to make sure it is for your vehicle.
i would love to run a 2.5" cat but my 89 came with 2.25 and by law i cannot change the size.
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  #55  
Old March 31st, 2012, 16:17
twodoorXJ twodoorXJ is offline
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Re: Joel's multipurpose XJ build (rocks/boulevard)

Nice work!
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  #56  
Old March 31st, 2012, 16:31
frijolee frijolee is offline
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Re: Joel's multipurpose XJ build (rocks/boulevard)

Stainless is overkill from a pure functionality perspective, but I've found on my rx7 that I've had the enhaust on and off a bunch. Details like v-bands just make it so much nicer to work on.

In regards to SMOG I'll take my chances. I've spoken with the SoCal regional director of CARB on a few occasions to clarify topics in regards to engine swaps and I'm pretty sure I'm fine. There are two approved catalytic converters for my Jeep. The direct replacement unit ($500) and the universal version that's the same cat as the direct replacement but without the piping on both ends (~$200). I went with the universal but the one I picked is OBD2 approved (it's engraved with the appropriate CARB numbers.) The CARB approval is referenced in the part details of the link above.

I built the system in 2011, but frankly if you're doing the work yourself there's no way to prove the installation dates so the Jan 2012 criteria is meaningless unless you're a shop.

This all gets notably harder when you have a different engine under the hood.

Last edited by frijolee; March 31st, 2012 at 16:37.
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  #57  
Old March 31st, 2012, 16:42
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yossarian19 yossarian19 is offline
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Re: Joel's multipurpose XJ build (rocks/boulevard)

Does anyone know the difference between the early style Jeep exhausts & the later? I've looked up both of them, around a 50 dollar price difference but I have no idea what the physical differences are.
The exhaust shop I go to is cheap / very competent... if it is just hanging locations, I'm sure they can work it out just fine.
Will older parts work?
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  #58  
Old March 31st, 2012, 18:27
frijolee frijolee is offline
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Re: Joel's multipurpose XJ build (rocks/boulevard)

Mid Skid / Belly Pan

Part of my plan in building a pretty nice exhaust was that I wanted to protect it when I was done. Combine that with the fact that a lot of catalytic converters are getting stolen so thieves can recycle the platinum in the grills (lifted vehicles being especially common) and I decided the best thing to do was to make a full belly skid.

Covering the Jeep from rail to rail is a big area and I was worried that what I built would either end up crazy heavy (several hundred lbs) or else be far too easy to bend. I’d seen a couple skids that incorporated ribs but instead I decided to make a full double decker skid so I’d get the bending properties of an I-beam with the ribs just being webbing. At the same time I didn’t want to make it too thick least I lose all the ground clearance I’d just gained with the tucked exhaust. I also decided to make it full width and replace the BDS transfer case skid as that was easier than making the mid skid tie into the BDS piece.

After a little wandering in my local industrial metal supply to see what was easily available I went with two sheets of 3/16” 6061-T6 and ribs made from 1/2” by 1” by 1/8 wall rectangular tubing (also 6061). Having just played with welding aluminum on my gas tank skid, I decided to use riveted construction for the main double decker portion of the skid. This was both because didn’t want to lose the parent material strength properties at the heat affected zone and because warping might turn out to be challenging. That being said,since the rivets top and bottom had to be staggered to miss each other I ended up getting the hole pattern water jet cut after I designed it all in CAD.

Here’s where I started:




The cutout for the driveshaft in the top skin is deeper because of the angle of inclination of the driveshaft. This was measured with rear axle at maximum droop with a extra inch clear just in case. It’s also worth noting that the driveshaft is not centered between the frame rails but rather offset by about an inch and half.

All rivets are 1/4" aluminum pop rivets with 1/2" heads. I found it’s hard to draw anything more than 3/32” with a hand tool so I bought the pneumatic version (Harbor Freight).

Then I started thinking about the fact that if I drag this over rocks too many times I could easily scrape the heads off the rivets and then have no way of getting the mushroomed end out of the ribs. Instead I went the hard way and proceed to counter bore all 100 or so rivet locations on the bottom side 1/16” deep so the heads were protected. I could grind them flush on the rocks and they’d still stay whole.




Fast forward a couple hours later and the metal shavings were about an inch deep




Here’s the internal ribbing:




All ribs were all match drilled to the top and bottom skins using the water jet pattern as a template. Ribs took more than 400 holes because I had to drill a larger hole in the backside of each rib in order to have sufficient space for the mushroom to form as the rivet set. The big holes cut into at each end void between ribs were sized so I could shove a garden hose in one end and flood out any mud or sand that might accumulate through the other hole.

Once the main deck was complete I moved into the means of attaching it to the unibody rails. It had to drop below the exhaust and I wanted the hardware to attach from the sides of the rails. I ended up using a whole series of pull to set 5/16” rivet nuts.






The sides are a series of tubes and plate (almost like mini boat sides) and I did have these welded to the assembled double deck structure.




The two cut-out details on side are there to clear the e-brake cable mounting assembly. I decided it was simpler to clearance around that design a new bracket. Note, the rectangular spacers along each tube surface are just that. The unibody rails aren’t flat and this let me spread out the load as I want the lifting force to be primarily vertical with the small 5/16” hardware just keeping it in place.






Weight… FYI: The BDS skid I removed was 8.5 lbs.




On the forward end of the skid I used horizontal bolts to tie into the BDS cross member/trans support. While test fitting I found it was faster to through on a couple of bar clamps to be sure it was all the way forward.




I ended up having about a 1/2" clearance around my muffler both top and bottom.




And here’s the finished skid from front and back.






This has about the same bending stiffness as a piece of solid aluminum ~0.813 thick. It’s kind of nice to not have to worry about high centering on anything. Now I just have to pay attention to the potential of hanging up on the diffs and rocks between the front wheels.

-Joel

PS If I ever throw in a different rear axle and it doesn't fit my skid, I'm going to be one sad puppy. This was easily a couple weeks worth of evenings.

Last edited by frijolee; March 31st, 2012 at 18:38.
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  #59  
Old March 31st, 2012, 19:17
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Vanimal Vanimal is offline
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Re: Joel's multipurpose XJ build (rocks/boulevard)

looks great, but no frame stiffeners?
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  #60  
Old March 31st, 2012, 19:24
frijolee frijolee is offline
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Re: Joel's multipurpose XJ build (rocks/boulevard)

Figured if I was spreading out the load enough I wouldn't need them. Thoughts / examples?

The drip rails are already welded in 3/16" rectangular tubes so I contemplated tying those in.
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