Hi all,
Should that A/F be upwards of 12.9-13-4 @ WOT and flat? I agree, that reported ten seems very rich at those Rs. I wonder what it's doing mid-range?
I found my best dyno numbers for the mustang to be 12.9-13.2 with a total timing at 39 deg at 3100 Rs. However, this is a low tech engine too.

 

Well Ken you are right on the money,
For Naturally aspirated engines you are correct. The best power would be around 12.8:1 depending on your timing setup this is the area you want to be in.
For supercharged/turbo setups you want around 12:1 depending on boost level.
Keep in mind these are for Gasoline based engines, ethanol and other mixtures will vary.

My guess is the we are seeing 10:1 with stock configurations to keep the exhaust and combustion temps lower. The down side to running a Fat a/f like this is the hurt performance of lower combustion temps and the wash effect the extra fuel does to the lubrication oil film on the walls of the cylinder.

Once I am able to locate a way to adjust the ECM I'll tune for different a/f at WOT and plot the data. I would not be surprised to see 30-50hp at the wheels for adjusting this in the tune.

Regards,
Derek Fricke

 

Hey Derek,
Do you know what the performance chips are doing for changing the ECM mapping?

 

Honestly, I've been trying to do research on this. I haven't been able to talk to a company that actually dyno tunes these cars. Seems everyone does mail-order tunes for them which leads me to believe they are just that. A standard tune that most tuning companies are offering. It's causing me to think it is just the XKR-S tune uploaded to the XKR. Maybe some a/f changes or timing adjustments.
I'm hoping to figure this out soon, If necessary I will get into the programming side and develop something to do so. I'll certainly make a thread on this topic once I jump into it in coming weeks.

If anyone has knowledge of an actually tuning software for these ECM's I'd love to hear it. Viewing the info surely sounds great with SDD, but I want to play with these tables.

 

OK, perhaps, it's a matter of finding that dyno performance shop having the tweaking knowledge on these engines. However, knowing Jag, there is probably some weird proprietary ECM functionality, that will prevent any real thoughtful tuning to be explored. I guess, this is why I love the design and assembly of my own aspirated V8s. Plug in an AFR kit and start tweaking the WEBERS/carbs, twist a distributor, adjust a vac canister, replace a few springs...off you go. Having a laptop to data-log the results ...."priceless" LOL!

 

You and me both bud. I like the ability to adjust parameters, plot graphs and fine tune. But nothing beats the ability to turn a screw and tune a car. I favor the same.
Hoping once I rap up this exhaust and dyno again for comparable date, I can move forward with getting the a/f where it needs to be. Next step after that would be headers, intake, and blower work.

 

Frizzle - Did you ever get a definitive answer to this question?

Like you, I am only looking to replace stock XKR center section with the Performance (XKR-S) X-pipe style of Active Exhaust. Hoping to be able to simply bolt in the new section and improve upon those amazing sounding pops/bangs without spending a fortune.

Looking forward to seeing (and hearing) what FrikenJag and bigdhenderson come up with!

 

I am not an expert (all though I know what an exhaust pipe looks like) I have a 2012 XKR with the "performance " exhaust. I am told it is the exact same as the XKR-S and has the X pipe. It is loud when in DSC mode or when over 3500 rpm. You also get over run and burble when down shifting which I enjoy. It is comparable to to some of my old Corvette's with side exhaust and my old Ferrari V8 . Some want it louder but IMHO this system is great.

 

All finished. I'll be working on a few muffler combinations as well as doing some dyno runs next week. Time to fine tune the sound I'm after.
Everything welded up pretty easily. There was plenty of room for the cat system and I was able to minimize a fair amount of the bends in this region of the piping. I was happy to see, there's a nice pocket around the stock manifolds. Looks like I'll be able to fabricate a set of equal length manifolds in there. It is possible to fabricate a set of long tubes as well, just would require a different location for cat.
Pertaining to the cats, I've witness no cell lights for the rear sensors. I'm using a 2.5" front section to the cat (Since the stock manifold cant accommodate a 3"). After the cat, 3" back. I've ran her for a few days now, pretty hard here and there, as well as start up and shut offs. Seems we are good there.
The tail section has minimum bends as well and to help prevent additional bends, I exited the tips so that they are kicked slightly to follow the body lines. I made the back section to be clamped in and out. So Altering the angle and mufflers will be a breeze.
And yes, the 3" piping barely fit. Still have perfect ground clearance thanks to the exhaust tunnel.
I've passed quite a few people with jaws dropped, the sound of this setup is rather monstrous. I certainly notice a difference in the pull and high end acceleration. It will be exciting to the see the numbers.
I must say, it was fun to bring her out to "Cars and Coffee" Saturday morning. This is a little event here in Charlotte every second Saturday of the month. I pulled through and every head turned with surprise. I don't think any of those guys have heard a mean sounding Fricken Jag
I'll get more sound clips and down shift vids soon.
Look forward to publishing before and after dyno vids next week.

Video clips are at the link below.
https://www.youtube.com/channel/UCfE...g4ytUX4OaigKfQ

Regards,
D. Fricke

 

Oh yeah!!! That sound awesome dude!!! Sounds alot like the Paramount system with a deep bass and kind of smooth tone.......how much louder is it than standard???

 

It has a much louder rev. The idle is about the same. I'll get some db readings today.

 

Very nice work! I have several questions though...

- What kind of material? Maybe it's the lighting but the material has a goldish tint to it...(I also cringed when I saw MIG welds instead of TIG)

- what mufflers are on in the videos you posted? (If any)

- what brand cats? Whats the flow rates of them?

- what's the butt-dyno results? (estimated power increase?)

Im sure I have more questions just can't think of them right now... Kudos on fitting the 3"!

 

Its all 304ss , I'll polish up once I test and tweak. I may add in 1/4 wave resonators once I test a few mufflers and decide which design I chose to move forward with.
(1/4 Wave resonators help eliminate drone/vibration at cruising speeds)

It is tig welded, just not the best photos, and certainly not the best visual weld. The color is the just the quality of the photo.
The video has the SLP LM2 designs. I'm testing a variety from magnaflow, corsa, to borla XR1 and XS.
Cats I'm using magnaflow 200 cell. I had them on the shelf. 2.5" so they would be in the realm of 350-400cfm I believe.

I'll have some numbers after the holidays.

Hope you are having good luck with your setup. Keep in mind, you want to limit the bends to be no more than 60 deg after your x-pipe. This is will prevent additional restrictions in the system.

Happy Holidays,
D. Fricke

 

I've cleaned up the thread so carry on where you left off gents.

 

Shame.....did not get to read the response!! Anyhow....water under the bridge......soo chaps my center exhaust build has been delayed to after xmas now.....i'll post up some pics and vids when done.....2.25" bore as standard dynamic rear box.....no need for anything bigger on my set-up.........3" bore should work well on a +600hp set up though.

 

Tomorrow is the day!!!!!

Custom X pipe being installed on my XKR........keeping the standard back box.......i'll be sure to post up pics and vid.......i'll also get a before and after db reading.......just for the hell of it!!

 

Thanks Damienedwards,
I'm awaiting your report. I have the same idea in mind when the weather gets happier.
What year is your ride? I don't see where you list it.
Happy Motoring....

 

Redrider.......its a 2010 XKR.....

Its a black one which makes it slightly louder!! Ha ha.....

 

Here is the after shot from when they did mine. It is massively louder, though I don't get to hear it so much from the inside. If I was able to wind the rear windows down, I'd enjoy it more because when I had them out for tinting the noise was incredible.


https://www.facebook.com/southportexhaust/photos/pcb.690819734312612/690811890980063/?type=1&theatre

 

Ha ha......now i'm worried!!!

Looks like exactly what i'm having done......so any more pops and bangs or just plain louder?? Any vids??

Cheers