I've heard all manner of such claims, and yet rarely, if ever, have I seen such claims been proven.

My standard statement in such situations, if you want a faster car, sell your car and buy a car designed to be faster by its manufacturer. Not only will this methodology cost you less, but the car will most likely be much more reliable and hold its resale value longer/better.

 

J-pipe definitely makes power and if your state doesn't do a visual you should pass assuming the 9th gen 3rd cat isn't monitored like the 7th and 8th gens. Precat deletes are good too but you may get a CEL and it won't pass a tailpipe test or a visual inspection. Plus you'll have to add a resonator to the exhaust to cut down on the rasp and drone.

Personally, if it was my car, I'd just do the j-pipe and spend the rest on larger anti-roll bars, upgraded struts and a mild drop.

 

I've seen dyno results of the XLR8 v2 J-pipe, 19 hp and 30 lb ft on a TL type S that was stock except for a K&N intake and a test on a 7th gen Accord where the v2 gained 10 hp and 9 lb-ft over the v1 j-pipe and an RV6 test pipe.

 

And did you retest a few weeks later after the computer had a chance to catch up with the changes? Chances are the net result was two maybe three horsepower at the most on the TL, and even then, only at high RPM at WOT.

 

Anyone who has an XLR8 j-pipe will tell you the improvements are noticeable and permanent. There are guys on v6performance putting down 250 to 270 hp at the wheels with j-pipe, pre-cat deletes, J35/37 intakes, port and polish lower runners and TBs, 4" cold air intakes, etc and running well into the 13s. And that's on the stock cams. Those using TL-S heads/cams are making even more. Honda J series engines have a lot more potential than people realize. And if your mods exceed the ECU's ability to handle, there are aftermarket solutions like Hondata.

Do you really think going from the stock j-pipe on the left to the XLR8 v2 pipe on the right is really only going to be worth 2-3 hp?



By moving the merge back, its basically the same effect as lengthening the collector on a set of headers. Big gains in torque, which is what Honda engines really need.

 

nice description and picture, i bet it would be a vast improvment.

 

Yeah....I am waiting on the J-pipe for the 9th Gen V6....supposed to be available around X-mas. HB

 

While there is no doubt that Accord V6 engines with TL head and/or cams produce considerably more power than a stock engine, unmodified engines with just the addition of a new J pipe will produce a only a marginal bump in power while at the same time will produce a measureable bump in pollution. Not a good trade off if you ask my lungs.

 

Considering the precats are still there, any increase in pollution is going to be negligible, otherwise the federal government would have made Honda monitor the 3rd cat. I had a '77 Cutlass with a 455 swap a long time ago and with no cats at all, it was .12 in CO2 away from passing the standards for a 1977 car with catalytic converters the first time through. Simply adjusting the idle mixture was enough to bring it into compliance. Modern cars using computer controls and using unleaded gas already burn a lot cleaner than cars from the 60s and 70s. That's not to say we should remove all pollution controls and everyone run catless, but removing one of three (and believe me, the 3rd cat is minimally restrictive anyway) isn't going to turn a modern car into a mid-60s big block running rich and loading up at idle.

And removing the precats and replacing them with precat deletes, you're on your own with that...even if you don't get a CEL (there are O2 extenders already welded in), you won't pass a visual and would have a tough time with a tail pipe test because unlike older cars, you simply can't lean a newer car out at idle by turning a couple screws.

In the end, someone with a 7th or 8th gen Accord, the only exhaust mods that make any real power are the precat deletes and the j-pipe and since the j-pipe is the one that will keep the vast majority of us able to pass annual inspections, its the best choice.