Mine were shipped back on Wednesday and should arrive back to NP on Monday. He mentioned he might need to have one of his customer's xkr to make sure if fits correctly after modifying them but the only problems is his customer doesn't have that much free time and so we'll see how long it will take to get it back.....hopefully his customer can come in sometime next week or there is no need to test fit and I can get them back by next week. Keep me updated on how yours go...I'll do the same.

 

sory to hear you guys. i looking to this when getting my xk. now i worry about them fit good.

 

Jason at NP got the cats back on Monday and contacted me that evening that everything is modified and will send it out Tuesday (yesterday).....so it looks like we'll receive it tomorrow. Now that is a fast turn around! Hopefully it will fit correctly this time.

 

Jason also called me the other day and said he was sorry for any
inconvenience, I believe he said he would call me to confirm what the proper measurements are supposed to be to help me determine if my cats should fit up properly or need modification.
Sure it is a bit of trouble but we are in somewhat uncharted terriorty and given the complexity of the bends it is something that is hard to do remotely.
GhostriderXKR08 - I hope your units fit up Ok.

 

The cats went back on Friday and it looks like everything fits. Shop was going to test it (new cats, ecu tune and air intake) this weekend. The shop did have some advice for minor tweaks and I passed it along to Jason.......will call the shop tomorrow...hopefully everything is ok!

 

u get back? update?

 

GN4HIR.......Jason from Nameless Performance advised and said you dynoed 20HP from the cats alone. That's awesome!

 

GhostriderXKR08,

Yes, 20hp.

Even more impressive when you realize it is not 20hp on top of the advertised 420 brake hp but a real 20hp on top of the measured 296 rear wheel hp. And while I didn't pick up much torque, notice how the torque band is extended over a broader range of rpm, .

I took the car to EngineLogics here in Houston. Brad did before and after dyno runs and installed the cats in about 2.5 hours. Even he was surprised how much hp it picked up.

When I took it in I had taken out fuse F19 which puts the active exhaust into always open mode. Before the cats it was a nice grumbling sound, after the cats it was loud and had kind of a crackle to it, not deep enough. Put F19 back in and it is a nice compromise. You can really tell when you edge over the rpm/throttle position and the exhaust opens.

Here is some data.

Before



After



Combined before & after



Active Exhaust Information

 

Very nice....I like the broad curve instead of the peak and dropoff. Not only that but it looks like the increase is in the fat portion of the power band. Thanks for sharing your dyno numbers and thanks to Jason at Nameless Performance.


As an off topic.....looks like we are below the 420HP advertise? 296.5 RWHP equates to approx. 355.8 HP to the flywheel which is about 64 HP below manufacturer's claim using a generous 20% (automatic tranny) parasitic loss to the drivetrain.


For comparison......

4.2L Supercharge: 296.5 RWHP.....approximately 356 HP to the fly.
5.0L Supercharge: 460 RWHP (taken from the dyno test from the XFR guys).....that means the 5.0L SC is in reality 552HP to the fly and not the 510HP manufacturer's claim.

I think I might have to dyno my XKR this summer just to see what it does.

If anyone knows the exact drivetrain loss for Jags...please let us know. Thanks.

 

The dynodynamics has 2 small drums per wheel causing more drag, and will thus give lower rwhp numbers. In the UK they even don’t test in 4th gear because of this, and only use 3rd, whereas on the road 4th gear gives more power than 3rd as it is more close to a 1 to 1 ratio (so less friction losses).

I have only limited experience with these units, so can't say what drivetrain losses could be in this setup, which are obvioulsy higher as you need to calculate the tire firctoin losses into it. I realy dislike these units because of the fact that the rwhp is also further from the actual power your wheels are putting down. Therefor I always try to use dynos that use 1 large drum per wheel, en preferably also that are able to generate a load via an eddy current). There are many things that can influence the results (i.e. low tire pressure, especially on the dynodynamics dynos), so without knowing all the environment parameters, correction factor used heat soak etc, it will be hard to compare figures.

As long as everything was about the same between the runs (so also not having the battery during the Cat swap), you could at least compare the results.

 

Avos,

All good points. I don't worry too much about the overall dyno hp number itself as there are so many variables. I'm just interested in the difference between before and after as an objective measure of improvement.

Joe in Houston

 

I just ordered a set of these cats yesterday. I can't wait to get them!

 

Sweet! Get ready for some LOUDNESS during WOT! I giggle everything I do a WOT. I drive slower now because any blip of the throttle I'm worried if I'll get pulled over for noise. Maybe GN4HIR can explain how loud it is with stock exhaust but with catback exhaust....it's LOUD during WOT....LOL. Funny story.....a couple of times a car would be tailgating me and so I let it roar and next thing I know they are following a good distance behind me. .....and they won't come close again.

My buddies (one with a Viper that is even louder) said not to worry as they've never gotten pulled over with their loud cars.....another buddy said my supercharger whine is louder than the exhaust......but I might switch to 300 cell down the road.

Avos.....thanks for the explanation of the dynodynamics dyno. Was alittle concern as the stock numbers wasn't that close to manufacturer's claim but now it makes sense that dynodynamics dynos less than others.

GN4HIR.....You're right....the gains is what matters...... BTW....do you know if these numbers are SAE corrected? Just curious......

 

Anyone wanting to see how loud is it with catback exhaust and highflow cats....here is a teaser coke video my buddy is doing on Youtube. The combo might be too loud for some.

The video is not finished but the teaser vid uses my XKR......You can also hear my Supercharger whine: YouTube - ‪Coke Commercial Teaser‬‏

 

@Ghostrider- I love it!

 

Thanks Moe! Did you get your cats yet?

 

@ghostrider-I got my cats the other day and took it for a test drive last night. You were too right, they are loud! I am a little concerned that they might be too loud. I figure I will drive it around this weekend before I make a final determination. Right now I have the 200 cell cats w/ the Mina Gallery axle back exhaust. The car still has a nice rumble on start up and low rpm but the pitch gets higher when you step on the gas.

How does your Jag sound in comparison to your AMG? How about other high end cars that you have heard?

 

Hey Moe.....good to hear you got it on!

I told ya it's loud...LOL....but I'd say give it a month...you might like it. I'm actually use to it now and wish it was a tad bit louder...LOL.

Compare to the SL65....the SL65 sounds like a Honda Accord. It's not til the later gen AMGs (say the last 2 years) did they have a nicer/louder exhaust note. Compared to my buddy's Viper with headers, rockers and straight pipe....the Viper sounds twice as loud as the Jag. The Jag is more of a low end growl (muscle car like) while the Ferraris, AMV8, Lambos have more of a high pitch note. My buddy's 997TT stock exhaust is actually pretty quiet and tame also. My previous Corvette was actually even louder than the Jag and you'll hear Z06/ZR1s and Mustangs with work done that are louder.

If you're concerned about being pulled over....I'd say don't worry if you drive normally. It's the WOT that might get you in trouble. It does sound loud inside the cabin because when the sound filters in the cabin....it echos inside. You can have one of your friends drive your Jag and you follow behind to see how loud it is during cruising and from a dead start....again....I did follow behind mine and realized it's really not that loud if they drive normal. Even Harleys and muscle cars are louder.

Again....give it a month.....you might like it by then.

 

BTW...here is a comparo between my Corvette and Jag......the Corvette was louder and I had no problems with the noise.

The Corvette had heads and cam, long tube headers, hiflo cats and B&B PRT exhaust (at that time):
MOV01556.mp4 video by lionheadxkr08 - Photobucket

The Jag:
xkr.mp4 video by lionheadxkr08 - Photobucket

 

I don't think that I can live with the noise! i am going to give it another week or so but I am leaning towards having the stock cats re-installed. My mother thought a truck was in the driveway when I pulled up today. As someone who regrets not going for the supercharger when I bought my car, I am willing to sacrifice the extra horse in lieu of a more civilized rumble.