Headers

Did you take a good look at the dyno results? something doesn't look right.

Well.... shows what I know. I am only familiar with the manifolds on the XJ, ZJ,and WJ models and assumed incorrectly that they were the same..

"Sneaky Pete" covert, hidden nitrous (or other augmentation-there are several gases that work, plus diluted H2O2 of course) systems are nothing new. Smokey Yunick did it. A woman named Judy Wagner dominated formula One air racing for a long time in an airplane her husband built with a secret feature-the fire bottle was actually N2O. And Detroit and Brooklyn street drag racers, vermin though they are, were notorious for all kinds of bizarre hidden hardware.

Where is your evidence it was a CNG bus...and if it was that the CNG had anything to do with it?

It shows a max HP (chipped) of 184 and 172 (non chipped)

Isn't the base 4.7 supposed to have 235 hp?

No Diesel exhaust stack:

I think the manifold on the XJ *is* the same, its the front pipes that are different.

When I was living in the Seattle area, the Seattle bus fleet was in the process of being converted to LNG, ostensibly to clean up the air and to save money. When it was found that LNG buses run as dirty as diesel, and cost more to operate into the bargain, the city went ahead with converting anyway. It was felt that the perception of cleanliness and environmental friendliness, was more important than the reality.

Earle

Found this article this morning. Check out the last sentence.

Point is if it was CNG, it didn't catch fire because of CNG, but because of poor maintenance on the brakes:

They won't help your TJ very much, but if you have a CJ or YJ they'll help alot!

The TJ already has a vastly improved exhaust tract, and unless yours is broken, don't screw with it. If yout TJ has an exhaust manifold (header) with a bellows on the end, it is already about the best you can do.

All this talk of "chips" shows the automotive world is mostly electronically ignorant hicks. The "chip" is an EEPROM or window PROM that costs a dollar or so. The software in it, is what you are paying for. On a per byte basis the software from aftermarket hot rod companies sell is insanely expensive. Usually it wasn't even software, in the sense of executable code, per se but just data of an "engine map", that is if X is such and Y is another, then Z.

Now they leave the physical memory part in place and flash it over the OBD II connector.

There is reasonably priced software to do this in some cases, or you replace the factory ECM with a unit having a common RS-232 connector and download your own engine map. California and other eco-fascist states probably do not allow this for on road use."Grassroots Motorsports" magazine has some things like this advertised therein.

All my hobby cars are old enough I don't have to mess with electronics and my go to work car stays strictly stock. Solves that problem pretty well.