This is on a Superflow Dyno which tends to run very low compared to other dynos I've used but the net change after the Nameless Cats was almost exactly 30 HP. Once I put the McLaud exhaust and Paragon intake on I'll run it again and post an update on my mod thread as I think I'm still constrained over the wheels on exhaust and the stock intake is a known issue.

 

Sweet! Thanks for the results!

You better hide this thread from SeismicGuy, he might have an aneurysm.

 

Respectable gain for just changing the cats. Any dyno plots for us to drool over?

Thanks for posting the results.

 

Wow! 30 RWHP seems like a lot for just swapping the cat for a tubular down pipe. Did you get a readout on any boost increase because of the reduced backpressure?

Did you run the car on the same dyno before and after? And the diff was 30 HP? That is a worthwhile investment. And you are saying there where no other changes except the downpipes?

 

Here I am. I have to admit I'm skeptical. Are these cats ones that actually have catalyst in them and would be at least semi street legal (of course here in Kalifornia nothing is street legal except for the potholes).

Doug

 

Do you have dyno sheet?

I suggest 'upgrading' our cars with CAI, 200 cell sport cats and LED's and you have 100 hp gain. Now you don't need spend money on twin scroll Kenne Bell Supercharger

This modyfication (adding 200 cell catalytic converters) in a well running stock engine can add up to 10 hp. Be realistic. More noise doesn't equal more power.

 

Here are the dyno charts, I rant full analysis the second time in prep for an ECU tune. Once again Superflows run really low so are best for just checking out deltas.

The first two show the runs on the Superflow, the last chart is an old Dynapack done around the time of the first Superflow just to show how low the Superflow is. HP is rear wheel.

I did add two resonators when I put on the Nameless cats (and these are cats not downpipes). I'd been running an x-pipe and just tail mufflers and the Nameless downpipes were so much louder that couldn't really drive the car so had to tone them down a bit. It is amazing how much loader the car gets when you put the cats on. I'd put in exhaust cutouts for fun when I pulled the resonators but with the Nameless cats the car was louder with the cutouts closed than the car had been with the stock cats and the cutouts open. And with the nameless cats and the cutouts open you'd wake the dead in the next county so they had to go. All of that happened between runs though.

Had a boost gauge installed in the meantime, boost was 12lbs at peak latest run.

Here are the pictures:

 

I exchanged mine stock cats (which are 400 cell) first with catless downpipes. The sound was 'dirty' and agressive but the car was to loud in cabin. Moreover the smell of exhaust gases was terrible:


I put on magnaflow 200 cell cats and the sound is almost the same as with the cat back exhaust and stock catalytic converters (I use X-pipe and two custom made rear mufflers):


I haven't dynoed my car after this mod but my butt dyno says there is no power gain although the sound is nice. The car is weaker in range 1500-2500 rpm. Acceleration times 0-200 kph are similar too.

 

gun4hire ran his on a dyno dynamic for before and after(the shop did the install then reran 2 hours later 3 runs before and 3 after temps to operating) and iirc was 25 more to the ground. So good gains

 

So Bob--what's the bottom line here? I want to make sure I understand the terminology. I thought the stock "downpipes" had integrated cats--am I wrong. If so, then the stock cats/downpipes are ??? cell and the new nameless performance ones are ???? cell and you got 30 hp just from that according to the dyno (fill in the ???).

Thanks,

Doug

 

How many miles were on the stock cats? They might have been clogged.

I gained less than 10 hp according to the dyno with Nameless cat-less downpipes. About 15 hp according to 1/4 mile testing.

https://www.jaguarforums.com/forum/x...es-dyno-41275/

 

The catalytic converters are built into the down pipes, Nameless sells replacements either with or without the catalytic converters built in. I bought the ones with the 200 cell cats. After pulling the stock downpipe/cats and replacing them with the Nameless downpipe/cat replacements I got about another 30 HP at the rear wheels. The detailed results are posted above.

 

If you're smelling exhaust gasses, you must have done something wrong. There is absolutely no exhaust gassing in my cabin and I'm really sensitive to fumes, so dunno what to say about that. I don't have much cabin noise, but I have a Borla center muffler and the Mina rears. It's not noticeably louder cruising than it was before, but it's much louder when you accelerate. At least with mine.

 

These are the factory cats:

These are the NP cats:



Perhaps you can understand why I think you're crazy if you think they only add sound. :P

 

The most aggressive improvement I ever heard over at the Corvette Forum from doing exhaust mod was about 25-35HP and that was from installing long tube custom headers. Even Nameless Performance were not touting 30HP increases (thought it was more like 11hp) and the manufacturers pretty much always overstate performance gains. Which is why the 30HP increase just from swapping the stock cats for the NP cats seems astounding to say the least. Still if that's what was measured I guess that's what it is.

Doug

 

I agree the original cats may have been partially blocked as that would explain the increase.

 

+1

 

I'd already changed out the exhaust so think that when I put on the new cats I finally got the benefit from the other changes (I was getting nothing from the other changes until I changed the cats). I can't explain it any other way though. I posted the charts.

 

Here is another thread with a larger exhaust, where just downpipes (without cats where installed). That yielded about 10-12 rwhp.
https://www.jaguarforums.com/forum/x...es-dyno-41275/

Most other dynos I've seen on our cars with sport cats where about the same. also on my car the sport cats would only have yielded 10 to 15 rwhp or so.

I would also guess that there where other things at play that gave you such a big difference, like jgaxkr suggested or something else, who knows.

Edit: LoL, I missed SteveM post earlier, sorry for the double post.

 

xenophobe, my exhaust is welded and sealed properly.

I mean crusing with widows opened with low speeds or fence gate opening when going to work, etc. It was quite annoying. Now, with sport cats the problem is solved, although I miss the sound of free flowing fumes

On the other hand there are many possible ways to get better sound from XKR.