99+ intake vacuum routing solution - JeepForum.com
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post #1 of 4 Old 12-07-2013, 10:56 PM Thread Starter
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1993 ZJ 
Join Date: Aug 2010
Location: Austin
Posts: 2,480
99+ intake vacuum routing solution for 93-95 ZJ

I hadn't seen this solution to routing the vacuum lines when swapping the older log-style intake for the 99+ version so I thought I'd give it a shot today during my manifold swap.

I pulled all the vacuum ports out of the new intake and tapped the holes for 1/4" NPT fittings. The outer two side ports got 90 degree 1/4" inverted flare fittings. I bent up some 1/4" steel tube connecting the new fittings to the locations of the two missing vacuum ports on the top of the intake. I know I could just buy longer vacuum hose but I like being able to order the stock plastic lines and have them fit without issues.

Here's the intake almost fully installed on the Jeep. It's a little blurry but it was 25 degrees out and my phone wasn't cooperating. I know the throttle body spacer doesn't add much if anything but I made it myself and I like it.

And just because I'm proud of it here's a shot of the intake ports showing the work I did cutting out the excess metal from the center four injector bosses. They are all the same size now.

So far I'm liking the new manifold but I've only driven it a couple miles.

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post #2 of 4 Old 12-08-2013, 05:58 AM
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1998 ZJ 
Join Date: Jul 2010
Location: florida
Posts: 7,918
Keep us posted! I think that is a real fine job there. What did you use to grind? I had thought about just getting the stuff off a WJ but never got around to it.

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Originally Posted by HighLonesome
lol...if life is as a simple as a 5.9 making you happy, I'd say go ahead and buy it on impulse. ZJs are the way of Zen. Wax on, wax off
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post #3 of 4 Old 12-08-2013, 09:47 AM Thread Starter
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1993 ZJ 
Join Date: Aug 2010
Location: Austin
Posts: 2,480
I used a six inch long 1/4" cylinder carbide burr. This one http://www.mcmaster.com/#4324a21/=ppwmfv

The extra length makes it easy to make sure the cutter is parallel to the port. When I had the shapes roughed in I polished out the cutter marks with a couple of Standard Abrasives cartridge rolls.
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post #4 of 4 Old 12-08-2013, 08:30 PM Thread Starter
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1993 ZJ 
Join Date: Aug 2010
Location: Austin
Posts: 2,480
Drove it about 50 miles today and my first impressions are good. The power seems better; maybe 5-10 hp. The throttle response is now much more linear. There seems to be a good gain in part throttle response. Just a quick check of my overhead console seems like mileage will be better.

Turned out that the loud rattling sound that I thought was piston slap was actually my power steering pump going bad. It was leaking from the rear pump seal and a couple times the steering lost assist during braking and sharp turning. The new pump had the same orifice so the steering effort is the same. I like having the tensioner adjustment access from the top instead of the under the pump.

Now to weld in the Flowmaster after cat I bought from HighLonesome, put in an MSD ignition, KNN air intake, shift kit, redo the from part of the exhaust in 2.5" mandrel bends, bored throttle body, cam, head porting...
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