Exhaust replacement - muffler back

[hellspcangel911]

I've been doing a lot of tinkering on my 86 Dolphin, mostly fixing random little things and adding some custom toys (Pics and new thread posted soon), I notcied the exhaust pipe is rotting after the rear axle, where it looks like National RV welded on a 90 degree elbow and ran the 6 foot tail pipe out. 

I would like to run the exhaust out the side behind the rear tires, the same as my 87 22r truck has it stock. I originally went to 4 local exhaust shops, 2 didnt want to touch it because its an RV, one quoted me $400 and the other $320.... mind you, this is only for cutting the old pipe behind the muffler, bending a new one and welding it in place.  I searched on here and popped over to RockAuto(dot)com, and found they sell the rear sections for about $20 bucks and stock catback systems from Bosal and Walker for under 100. 

The pictures they have are so small its difficult to tell which one is correct for the 21' RV, and they wheel base options they give are 103 and 112", I measured mine and it was about 143".... what are the proper ordering parameters? 

I noticed soemone posted they purcahsed the parts at Napa, anyone else purchase a pre-bent piece and what criteria did you use? how did it fit?

Thanks!

[hellspcangel911]

According to ToyoDIY, my vin shows up as a Rn75 chasis, just short of 140", which is the 'XL Wheel base" only a few sites show. and is under the Pickup DLX 22R or RE, no difference.

Toyota no longer sells the full exhaust and it would be over 300 for the catback anyway. 

there are surprisingly a lot of options, primarily from Walker, AP and Bosal. These are all pretty good companies, in most cases far superior to what your local muffler shop would use, I would rate Walker as one of the best for this application as they're pipes are Al treated.

BOSAL has the catback for $100 with the exhaust and rear tailpipe (288983)  http://info.rockauto.com/Bosal/Detail2.html?08442225.jpg

the tailpipe piece which most shops appartenly charge over $200 to bend, is available for $15 from Rock Auto. Walker has one for $30 from Amazon.com, the Muffler is about 30 as well.... just check Rock Auto, they have all the options laid out quite nicely.

I ordered the cat-back system for 130$ shipped since i found a leak in my muffler, this being designed for the rn70 will have a shorter intermediate pipe between the cat and muffler so I will either cut existing intermediate pipe, weld on a flange and bolt it to the catback or put a 1 3/4" coupler and weld it. Maybe just cut the cat out and put a testpipe in its place going to the flange on the catback. 

I hope this helps someone out there looking to mend their exhaust for cheap, but do it right.

[Derek up North]

Thanks for the useful information. Hopefully people will find it with the 'Search' function when the time comes!

[bufbooth]

I had thought that going out the side with the exhaust was a bad thing to do, that is

it will allow exhaust / CO2 to enter the rear of the coach. On a pick-up truck it is not

a problem since the end of the exhaust will be 3 or 4 feet past the cab area.

Dennis...

[hellspcangel911]

I had thought that going out the side with the exhaust was a bad thing to do, that is

it will allow exhaust / CO2 to enter the rear of the coach.  

Dennis...

Valid observation, but not really a concern. Most RVs have the exhaust plumbed out the side for both generators and engines as it produces less heat underneath the already crammed belly of the beast. 

You do have to consider the exhaust and fumes, some RV owners will re-rout their generator exhaust up the side of the RV or extend it further away from the rv with removable piping both for fume and noise considerations when parked. With these small 4 and 6 cyl engines, as long as the muffler is installed, and the pipping routed away from the RV (i.e. NOT simply putting a 90 degree elbow on the current exhaust right after the muffler), I wouldnt worry about it at all. I guess the rule of thumb would be to go out the side at least as far as the last opening side window. 

[Seattleguy]

My shop did an exhaust manifold, 02 sensor and everything new from the cat back for somewhere around $500. They rerouted it out the side behind the tires, as the old one was mounted close to the holding tanks (which i wouldn't want to melt!) and out the back (too many bends). They also used a little bigger tailpipe, which helps a bit with airflow. Sounds a bit 'beefier', as much as a little 4 banger pushing 5k pounds can be!

[WME]

My local did cat back, w/muffler and new custom bent 2.25" pipe. $275.00

[wetboy]

When I first got my Toy in Salt Lake, it was developing stuttering problems by the time I got to Vegas. I thought it might be a clogged Cat. Stopped at this little Mexican guy's shop on a Sunday afternoon and had him cutoff pipe in front of Cat, weld new 2 1/2 in pipe to that, and install new basic muffler. The rear 6 ft 90 degree bend ending behind tires was left off, as I had a section of that at my destination in FLA. Total was $120 cash out the door.

I didn't solve the problem (turned out to be massive rust in the tank) but it sure helped my low-end torque! FLA doesn't require inspections anymore, so I didn't care about the Cat. If I ever have to register it elsewhere, I'll have a cheapie put on. Eventually put on that rear section using flexible exhaust pipe, and it def helped with fumes in the coach and quieted things down on the highway, fashioned some hangers with some stainless steel strips I had. Originally had coat hanger twisted up, and they were still good after 6000 miles! Is there anything some duct tape and some coat hangers can't do?

The thing that REALLY pissed me off was, I told them to throw the cat in the coach, as I knew I could pay for the whole job just selling that back in FLA. But I was in a rush and didn't double check that. I was in San Diego before I figured out those wily Mexicans got my cat! Grrrrrr!

That rear section is starting to develop some rust, so I'm gonna hit it with some rust converter, then a butt-load of high temp BBQ paint I got laying about. It gets hit with all that tire fling, so it deserves a good coating.

[WME]

Instead of BBQ paint check out 3M Schutz. You can get it in 17oz rattle cans, or use a Schutz sprayer and it comes in qts.