I am aware that there is a recent thread regarding tuning and normally aspirated engines, but I wanted to start a new one as a single point of reference for information as I add it. If I'm being redundant or if I need to simply add this to the bottom of the earlier thread, could one of the Mods let me know? Thanks.

Yesterday I began the arrangements to get my XK tuned by fellow member AlexJag. As I am a bit of a completist and a numbers nerd, I will be putting together as much information about this as I can and recording it here, hopefully so that future members can reference it and make decisions for their own cars based on what is learned here. There's not a lot of info regarding normally aspirated jaguars and tuning that pops up though Google, so I'd like to turn this into a useful tool if possible.

My car:

2011 Jaguar XK
5.0l normally aspirated engine
76,100 miles
All previous work done by Jaguar dealers
Only issues the car has had is a constantly faulting water pump and driver's side door lock actuator

The expectation is to gain probably around 25HP and complimentary torque. Having the torque move down the RPM range would be a nice added benefit as well. Personally I'd like to see gains of 35HP but I don't know how aggressive the factory tune is versus what I'll be getting. I don't know if the tune that AlexJag supplies affects things like shift points but I will relate that information here as I learn it.

This will be with no engine or exhaust mods. At the moment this is an experiment relating to the tune alone.

A gain of 25HP would be a 6.5% increase over the factory claims which is a number that I feel is well within safe daily operation of the engine and powertrain. The cost per horsepower at 25HP would be $26/horsepower which is in my mind an economical trade.

My intention is to have before and after 1/4 mile runs as well as before and after dyno pulls. I already have 1/4 mile slips so that part is finished. I personally feel that before and after 1 mile runs would demonstrate the changes more effectively as this car simply isn't geared for the quarter, but since I'm about 1900 miles from the sand flats that isn't happening.

What I am curious about: Is there any piece of information or data that users would like to see? I can data log the output from OBD which should show A/F ratios and so on, but posting that info might intrude on AlexJag's proprietary knowledge regarding how to tune the car. I don't know.

If someone has suggestions, warnings, or thoughts now is the time to let me know so I can incorporate it into my plans. This should be taking place over the next few days.

 

Sounds interesting and will be nice to see the before after data to determine if it is worth the effort. Personally, I drive in sport mode with traction partially off (or all the way off) and paddle shift, when in the mode and driving aggressively I find it is plenty quick, more is always better, right? I have never increased 385hp by 25hp so can't tell if the butt-dyno would prove out the increase or if the cost and effort would cause placebo affect.

The before and after drag times will be the best indicator, dyno graphs are nice but real world results are what matters.

 

I'm not entirely sure that more is always better. The car has plenty of quick for 99 percent of my driving and it certainly has enough juice to put the back end in front of the front end if I want it to. I guess it always feels like the car has just a little more to give that's being held back, plus from a psychological standpoint I'd like to have that 400+ HP bragging right. I would be thrilled by a drop into the 13.1s as far as the quarter is concerned but I am thinking that'll be a stretch with only a 25hp boost.

If the torque curve moves lower then I suspect I could certainly feel that in the buttometer but I'm not sure if that can be accomplished by tuning alone. A good exhaust would do it but I am not going down that road without also swapping out the manifolds for actual headers, and frankly I'm not sure if the loss in vehicle value from that work would actually be offset by power gains. And let's face it if I wanted to start bolting crap onto the car and cutting things off I'd be better served by a Mustang.

And I do not want a Mustang.

 

Excited to see the results,
Could you post your current LTFT (long term fuel trim) first please.

I'd like to see where your car is at right now in terms of air fuel ratio.

 

LOL, agreed. Although I am thinking there might be a member with a built-up Mustang. Note throwing shade on that choice!

By the way, you seem like a good guy so I apologize if I was short in the other thread. Look forward to your results and like you said, it is decent hp to cost ratio so no worries.

 

I am very excited about this thread, I will probably add my data to it as well. I have the same car, with very the same miles, so it will be very interesting to see what two of "the same cars" end up with result wise. I am planning on having a dyno run in the near future, the show I was going to use it just a bit backed up. I cna't wait to see what all happens here!

 

I've seen a number of insanely powerful and well built up Mustangs. Being an old school Ford guy I actually quite like the looks of them and that Coyote motor is a fine piece of engineering. I just don't want a Mustang.

 

This will be fun! And maybe some valuable real information for people that are considering a NA tune. I hope.

 

Both banks are showing long term fuel trim at -3.9%

The secondary O2 sensors are at 0.0% on bank one and 0.8% on bank 2

 

Id like to hear your theory on how you figure out afr ratio out of fuel trims.. 🤔. 😆 let's hear it. Don't mean to make make fun but this is amusing ..

 

I was curious about that but since it’s two different paragraphs I was thinking those are two unrelated thoughts. He didn’t ask for any specific A/F data so I didn’t post any. I’d have to display it as a table anyway. I can tell you it’s stoichiometric when idling, I guess?

 

Thanks for posting that,

+6 and +9

not sure how to fix it still

 

My understanding its that anything under +-10 is not to be worried about, but I'm not as familiar with an engine that is as picky refined as a Jaguar motor. My initial thought would be not to be concerned about it.

 

AlexJag: I cannot send you any private messages or answer your latest one. Your mailbox is full.

 

Thnks ,, fixed!

 

I wanted to post up an update for anyone who is interested, as it was supposed to be a big week on this end, although things seem to have changed.

Much to my chagrin and to my detriment it looks like user AlexJag is not going to be working with me on this particular project. Entirely my fault. My understanding is that he is working with a tune that he spent roughly two years developing, so hopefully others can benefit from that work and report it here. The original plan was to have the tune in the car by the end of the week. That isn't going to be happening now but I still have a schedule laid out pre-tune that can be followed and should provide some useful information to mull over.

9 AM Wednesday the car goes on the dyno for pre-tune pulls. I'll post that up here. I also have a few 1/4 mile time slips that I can post up as well.

Sometime Wednesday my battery maintainer will be here. I've read the horror stories on here about what happens if the battery dips while you are messing around with the ECU and since I'm not overly interested in bricking my XK, I want to make sure I have that in hand and connected before any tuning takes place.

Friday I pay the car off. TOTALLY FREE AND CLEAR, BABY! So I guess now if I break things it's on my head.

My plan B, tune wise, is to go with RSC whom I had talked with before I ran into AlexJag. I will contact them in the morning tomorrow and report back here as to a schedule regarding the actual tune proper. My dyno place needs about a week lead-time so I have the follow up pulls in limbo at the moment. Again, I'll post up here what that schedule looks like once I know it.

This is the last chance for anyone to throw recommendations or requests my way. If there's anything anyone would like to see pre-tune or if there's something you think I should do, now's the time to sound off.

 

I look forward to seeing the results but make sure that your maintainer can supply a steady 30 amps and not just 5 amps like a traditional maintainer otherwise you may still have issues.

 

What he said ^ ^ ^ ^ ^
Here's my power:
https://www.tractorsupply.com/tsc/pr...duct-_-4700068

 

Gack. I don’t have the specifics in front of me but I’m pretty sure the one I ordered is 15 amp. Gosh darn it.

 

25A should suffice provided your battery is healthy