Series 73 Repairs + Modifications

[Terrys]

Now, with all that said, the NRP system sure looks pretty once installed:

What doesn't look pretty on that truck, Jeff?

I put an NRP CAT back system on my 110. The pipes all lined up well and still looks good 3 years later, but the hangers were a bit, uhhh, yew yaw.

[Tim Smith]

I can back up what Jeff said about the NRP and I too have a lightweight. Unfortunately I didn't get the fortune of having Techtonics Tuning fix the tail pipe. To be honest though, I'm running larger tires than stock and so it's hard for me to say my truck isn't out of spec. When I had the install problems, RN directed me to their shop and that was pretty much the end of my search for a fix.

Jeff, I almost wonder if the lightweights aren't laid out different some how. Just a thought because I've not heard of any standard 88's with the same issues. We couldn't be the only two who bought the NRP, could we?

Here is the exhaust alignment on my truck with my "final bracket" clearly shown. That bracket has lasted the longest at over a year with some hard trails in between.





And shooting straight down. Of course the wheel will move backwards on flex, so this only gets worse.



This is one case where I would advise either getting original or having a shop make up a 2" exhaust for you.

[jac04]

.. I almost wonder if the lightweights aren't laid out different some how.

Well, when compared to a civilian 88":
The wheelbase is the same
The engine & trans are the same
The driveshafts are the same
That puts the rear axle in the same position relative to the engine, so a regular 88" will have the same tail pipe issues. Can't say for sure about the hanger location on the chassis.

Either way, the NRP system could be a good system if they:
1) Made the 'ball and socket' connection at the manifold the same as original.
2) Added another 'ball and socket' at the intermediate pipe to allow for adjustment of the alignment. A flex section could also be used here.
3) Changed the tail pipe design per my design.

[Tim Smith]

Yeah the wheelbase and mechanicals are the same but are you sure the drive shafts are? The only thing I can imagine is that the engine and trans were moved forward a hair and that was hidden with the body changes. We know the firewall out-riggers are different but while they were at it, could they have moved them forward?

Again this was just a thought that I had because you and I are the only ones I know of who have had fitting trouble. I never looked into this or anything.