Don't know yet; I only did the base runs so far. I'm scheduled for the after runs on Sept. 1st.

 

@SteveM

I had the xpipe earlier, but it was just too loud and droning, so had to sell that one. I think it is somewhat exaggerated what you can gain with them (bigger exhausts in general), and I would have to see some creditable dyno tests on our cars. Maybe you can get a little bit more, but not enough for me to make it worthwhile. Also I never noticed a difference, and a dyno test did not show more horses, though the difference could have been within the margin of error (it is hard to get comparable dyno runs). So I would not spend money on an exhaust for more power, only if it is for a different exhaust sound. For me the sports cats are working out very well, in all rev ranges, especially in tunnels ;-)

In general the best atf ratio is about 12.5, however that is already pretty sharp, and the smaller the tolerances the quicker you could run risks, so you would also need to be careful with the timing. Upper 11 would be a nice value imho, still some tolerance left and also some room to up the boost ;-)

What where actually your baselines results?

 

[quote=

We'll have to work on some trick looking engine bay products.

Jason[/quote]

I really hope that you do, as these Cats are gorgeous, and I for one, would be up for more enhancements of similar build quality!
Regards,
Brian

 

So as not to hijack Brian's thread with my stuff:

https://www.jaguarforums.com/forum/s...ad.php?t=41275

 

Waiting on dyno results !

 

I haven't dropped the ball, I'm waiting on two things. One, I need a nice, hot, muggy day, just like the one when I had the first runs done. The Tropical Depressions offshore have lowered our temperatures a bit here in Florida. Two, the Dyno Shop was changing out their CD Rom so that I can get more than just a printout. Jason wants all the data files, and I am also going to email it to Andre (AVOS). It looks to be hot tomorrow, so I have an appointment for 2:00. Hopefully, it will get done as scheduled.
Brian

 

That has also been my experience from lurking around on the Corvette forum for the 14 years that I owned my 95. The first thing most folks would do was to shell out fairly big bucks for an exhaust system to replace the OEM. Then those same folks would complain about the sound and resonance inside the cabin. Those that bothered to dyno before and after would typically show negligible increases from the new exhaust--lousy bang-for-the-buck. These types of bolt-on mods are really pretty useless unless they are done as part of an overall package that included improved intake, improved heads and/or cam, etc. Even then the benefits are likely to be noticed only at wide-open throttle or on 1/4-mile drag runs.

Doug

 

Hi all,
OK, the follow-up Dyno Runs were completed today, and I picked up 11HP! I tried VERY hard to schedule this run on an equally hot day, but it actually ended up being 4 degrees hotter today, at 95 versus 91 last time. I can't speak to anyone else's expectations, but speaking for myself, I am very happy with my new Cats. They are extremely well made, pleasing to the eye, create an absolutely beautiful sound, and yield 11HP more. I think Jason and Nameless Performance are to be commended for a job well done. In my mind, my Jag has just evolved once more, and is racing up the Evolutionary Chart. My only regret is that these beautiful Cats are not more visible, as they truly are "Eye Candy".
Brian

 

Doug, I'd respectfully disagree when it comes to the XKR & XJR. I know after talking to Bill MacLeod he sees about 24hp (consistently, from one car to the next) at the wheels with nothing but a catback exhaust. On top of that our downpipes make 11hp, so you're looking at a 35 rear wheel horsepower upgrade in a full manifold-back exhaust. That is substantial for any car.

While I see how some bolt on improvements may not provide gains on a naturally aspirated Corvette based on its original design configuration, bolt ons for forced induction vehicles are usually quite substantial. I know with a downpipe and intake on the 2010 turbocharged 2.0L Mazdaspeed3, I managed to get 50 ft lb of torque improvement at the front wheels.

Each car really is unique in finding the best ways to reclaim power that was left on the table by the OE manufacturer.

As far as drone goes on exhausts, there are a multitude of ways to make a free flowing (read: straight through style resonators) exhaust that does not drone. The droning isn't so much a function of the X pipe as it is a function of having certain frequencies remaining after the exhaust pulses have passed the resonator. We've got a friend of the shop who is getting his PhD in Computer Engineering, specializing in waveform analysis and acoustics. I think we'll be doing some proof of concept testing on one of our BMW's here and then potentially throw our solution onto Dan's XKR if he'll let us. The design would be modular and once we establish the drone frequency to band-pass, the solution could be added to any exhaust on the market for these engines.

Shameless Plug: Buy our downpipes here. There are three sets left at the 20% off pricing.

 

I am not really arguing the fact about whether or not you can get a few more horsepower by fiddling with the exhaust but what I am pointing out is the bang-for-the-buck factor. Aren't we looking at about $2,000 for the cat-back system plus installation? That is not exactly chump change but if you really need to have the extra 20 or so horsepower, go for it.

Doug

 

@nameless

I also know of some cars where the x-pipe didn't deliver this amount you referring too, and certainly not on my car even though I was then (when I had the x-pipe with stock cats) pushing huge amounts extra horses thru the system, so I would have actually expected much more.

Agree fully with Doug, a couple of 1000 dollars for a cat back exhaust and just a little bit extra hp seems expensive to me if that would be the prime purpose. It might be more justifiable if one also chooses an exhaust for the noise.

The sport cats with stock exhaust has given me a perfect sound; no idea if this gives me extra horses, am enjoying it for the sound alone.

As mentioned earlier I wish you would have been here earlier, I have paid more than double for my sport cats (although they also are of prime quality and deserve to be shown).

 

In all fairness, Nameless has been very careful and objective in quantifying any horsepower gains for his downpipe. However, in general I agree with Avos and SeismicGuy. Aftermarket exhaust system power claims made by enthusiastic manufacturers and hyped-up butt dyno owners are usually way overrated. On forced inducted motors the enhancements can amount to significant gains, but on naturally aspirated engines the increases are not that much.

Sure, you get a few ponies for better breathing, but I am usually suspect when the claims of 20-25% horsepower are made for NA engines. I've seen some back to back dyno runs wherein the full freeflow 3" $1200 stainless catback made less than ten HP because somewhere along the system was a choke point that had not been addressed.

Regarding the XK8 downpipe; after one look at the existing OEM box it is obvious straightening out and cleaning up the gas flow would provide some easy power. So a claim of 11 HP sounds reasonable. However I am not sure the downpipe and cat back gains are cumulative. I would think they'd be complimentary, but I don't think the two gains can just be added together and get 35 more HP.

If guys want to drop some big bucks for better sound and/or stroke their pet car; hey go for it. We are all car nuts. I'd love to see thousands sold and maybe one would be on the next Jag I buy. But if the argument is Most Bang for the Buck, for myself, I'd save up the $2300 and put it towards an XKR where I know I will see the extra power; and know there is lots of room to get even more.

 

Actually they are. Our dyno tests that yielded 11hp were above a baseline of a MacLeod xpipe exhausts on both Steve and Brian's cars.

I agree with a $2300 exhaust package being hard to swallow. Makes me want to consider offering an exhaust system as well, but we have been talking to Bill about pairing our cats with his exhaust systems in the future so we'll probably hold off on that for now.

Jason

 

I knew my butt dyno was not off! lol
Brian: how much torq did you pick up?

I am so glad i brought my jag to these guys for this. the Outcome has far surpassed my expectations.

 

Hi Dan,
I'll have to pull out the paperwork and look it up. We are on our way to Montana for a week of Hiking right now. Jason or Andre might chime in, as they both have my Dyno Charts. Yesterday, on an Entrance Ramp, I had to really put my foot into it for the first time since the new Cats were installed. Holy Smokes, the acceleration was SCARY, and the Jag howled like a Banshee! It was great, I loved it, and later thought that if that is NOT "Bang for your buck.", I don't know what is! I had a goofy grin on my face for an hour. Every time that I watch "Top Gear", they praise a car that has that Sports Car Snarl, as the Aural evaluation carries huge weight with them. I think that they would now approve of my Jag too, as it sounds fantastic in my book! I'm definitely a Happy Camper!

I hope that you are making headway with your various codes, I know only too well what a pain in the *** that can be. Good luck.
Brian

 

I finally installed my new cats! I am defintely a happy camper. The quality, finish and performance of these are great. They fit perfectly and no check engine lights.

They have a super cool sound and definitely some extra power.

For those who want to do it themsleves, I have written up some instructions. Sorry no photos, but the procedure is pretty detailed.

 

Congratulations on the "self install", my hat is off to you. I had a bit of Heat Shield vibration, just at start-up, but a trip back to my installer quickly took care of that. I can't get over the improvement in the sound, as the Jag feels like such an high-end exotic now! I truly enjoy driving this car, and to me, it now looks right.............and sounds right. Enjoy yours!
Regards,
Brian

 

Brian-

Thanks for the comments !

I did happen to notice that on the drivers side one of the heat shields in the cavity was touching the cat. I just bent in slightly away it away with a large screwdriver. I did not think to put it in the write-up but since you mentioned the vibration problem, I will add it in shortly and repost it as rev 3.

 

Thanks for that tip, mine was emanating from my Driver's side also. I'm glad to know that it might be such an easy fix should that vibration return. The mechanic had left before I picked up the Jag, so I was unable to chat with him about it. In any case it is gone now, and "my Cat" has a nice a very nasty snarl now!
Brian

 

So I'm definitely going to add Nameless Performance CATs. Are your systems stock back from the CATs? Andre cautioned me the CATs alone give him the sound he wanted, too loud with X-pipe and aftermarket exhaust. I want the growl when I punch it, but certainly don't want the drone. Is leaving the Resonators the key to maintaining a tolerable sound level...with or without the center muffler? What about replacing the pancaked over the axle pipes? Guess the best approach is replace the CATs, leave everything stock and take it from there.