Remap x351

[Zippyworld]

Hi

Has anyone remapped a 3.0 Litre Diesel X351 ?

If so, was it worth it ?

[8bit]

Zippyworld said:

Hi

Has anyone remapped a 3.0 Litre Diesel X351 ?

If so, was it worth it ?

Not me but a chap I know through my time with Jags, he has an X351 XJ L with that engine and had it remapped. Not sure where he went for it but I can find out if you like? In any case he was very pleased with it as I recall.

[Zippyworld]

Thankyou, I am North West based and would appreciate a recommendation

[8bit]

I messaged the guy about his remap, here's his response...

Bloke from Jaguar Forum said:

My remap on the XJ X351.....I used Quantum tuning for mine in Glasgow and very happy with it, no issues.
I went from around 300bhp stock to 350bhp remapped and 700nm stock to around 780nm remapped, works very well and does what it says.
Also Jaguar say a range of 728 miles and you know they're being optimistic at that, I've seen 852.5 miles on one tank, when driven carefully ( Ie like Miss Daisy ) and reckon 900+ is a possibilty, so helps on economy too.
I seem to remember around £300 for a remap, if he was using Glasgow I could put him in touch with them directly, may get a bit off.

I believe they will have other set ups around the country.

[Zippyworld]

I would be delighted with this return.

Thankyou

[GeniusOfLove]

On an engine known for bottom end weakness, and massively exceeding the input torque limit of the ZF gearbox in the process.

I've remapped cars in the past and broken every single one of them, I really would think carefully before doing it if the car has any real value left in it and if you intend to put real miles on it.

Many of the "I remapped my car and it was FINE" brigade do 5000 miles over 2 years in their Golf, or neglect to mention that it immediately needed a clutch and DMF and they only kept it another 10k miles.

Some engines do take it better than others, I doubt the AJDV6 is one of those, when I had a diesel X351 and was frustrated at it's performance at more than mooching speeds it didn't seem worth the risk for it still to be not really that fast.

I'm not saying don't do it, I'm saying don't believe the claims that sticking 20% more power and torque has zero impact on component life and durability and that you might not be taking something way over what it can tolerate long term. I do wonder how many of the mangy dead "blacked out window and wind deflector equipped" Range Rover Sports with snapped cranks on their AJDV6 you see at BCA and Copart had £299 remaps.

Edited by GeniusOfLove on Tuesday 15th August 10:38

[8bit]

GeniusOfLove said:

On an engine known for bottom end weakness, and massively exceeding the input torque limit of the ZF gearbox in the process.

I've remapped cars in the past and broken every single one of them, I really would think carefully before doing it if the car has any real value left in it and if you intend to put real miles on it.

Many of the "I remapped my car and it was FINE" brigade do 5000 miles over 2 years in their Golf, or neglect to mention that it immediately needed a clutch and DMF and they only kept it another 10k miles.

Some engines do take it better than others, I doubt the AJDV6 is one of those, when I had a diesel X351 and was frustrated at it's performance at more than mooching speeds it didn't seem worth the risk for it still to be not really that fast.

I'm not saying don't do it, I'm saying don't believe the claims that sticking 20% more power and torque has zero impact on component life and durability and that you might not be taking something way over what it can tolerate long term. I do wonder how many of the mangy dead "blacked out window and wind deflector equipped" Range Rover Sports with snapped cranks on their AJDV6 you see at BCA and Copart had £299 remaps.

Edited by GeniusOfLove on Tuesday 15th August 10:38

I'm not saying you do, but if you drive a remapped car flat out a lot of the time (thus pushing things like transmission or drivetrain components pasted their rated limits) then yes, clearly you can expect to have issues. Most mapped cars I've known that suffered some catastrophe like this would have been abused as such. Many would have been abused like that before remapping and cars like the example you gave in your last paragraph will almost certainly not have been treated with much mechanical sympathy.

All those cars you've personally had remapped that have "broken", have they really all broken specifically due to having been remapped?

[Zippyworld]

There is always an element of risk I guess.

I have remapped a couple of my cars, the last was my 2015 XF. 2.2 Td.

I have had no problems, but then again neither were hammered.

[piquet]

i'm now on my second x351 and must be in excess of 170k now

i've never had a problem with it or found it needing more umph

it's a diesel so has the limitations associated with it, but in sport and performance mode it will certainly gain speed fast enough, to get around any slowness of the turbo, you just flick it down a couple of gears before the move sp everything is spooled up.

they're big cars with suspension for comfort rather then performance

it's up to you, but I wouldn't swap any marginal increase for the offset of the risk. I find it more the fast enough when i want to over take on NSL roads and if you're not careful can easily hit licence losing speeds when you've pulled back in

[Zippyworld]

I guess I am just spoilt with the performance of my XJR 😂😂

[GeniusOfLove]

8bit said:

I'm not saying you do, but if you drive a remapped car flat out a lot of the time (thus pushing things like transmission or drivetrain components pasted their rated limits) then yes, clearly you can expect to have issues. Most mapped cars I've known that suffered some catastrophe like this would have been abused as such. Many would have been abused like that before remapping and cars like the example you gave in your last paragraph will almost certainly not have been treated with much mechanical sympathy.

All those cars you've personally had remapped that have "broken", have they really all broken specifically due to having been remapped?

Yes I gave them a hard time, why remap the car if you're driving it gently?

Failures were all things that would be rare on a standard car, fair few clutches, automatic gearboxes, bottom end failures, and I even managed to kill the driveshafts and "unburstable" six speed manual gearbox in a Volvo.

Never broken a standard car driving it hard though.

The OE engineers know what these components can take and calibrate accordingly, it's not just about headline (and often bullst) tuner power and torque figures, it's instantaneous spikes and so on that will be taken into account in an OE calibration and thrown to the wind by a tuner. Same goes for the transmission, I'm sure ZF didn't pull the input torque limitation figures out of thin air.

OP - if you're after more buy a supercharged one, the jump from the 4.2 s/c XJR to the 5.0 models is much more dramatic than the paper figures indicate. They're superb, and generally very tough.

[8bit]

GeniusOfLove said:

Yes I gave them a hard time, why remap the car if you're driving it gently?

Failures were all things that would be rare on a standard car, fair few clutches, automatic gearboxes, bottom end failures, and I even managed to kill the driveshafts and "unburstable" six speed manual gearbox in a Volvo.

Never broken a standard car driving it hard though.

The OE engineers know what these components can take and calibrate accordingly, it's not just about headline (and often bullst) tuner power and torque figures, it's instantaneous spikes and so on that will be taken into account in an OE calibration and thrown to the wind by a tuner. Same goes for the transmission, I'm sure ZF didn't pull the input torque limitation figures out of thin air.

OP - if you're after more buy a supercharged one, the jump from the 4.2 s/c XJR to the 5.0 models is much more dramatic than the paper figures indicate. They're superb, and generally very tough.

I didn't say "gently", but it is still possible to drive a remapped car with mechanical sympathy and enjoy the extra output from the engine. I've had mapped cars myself, driven them enthusiastically and never suffered the issues you have. If remaps were essentially a guaranteed way to kill a car, nobody would be buying them...

100% agree on the last paragraph though - I went from a 4.2 XKR to a 5.0 XKR and it was a much bigger leap in performance than I'd anticipated. I still remapped the 5.0 car though, but that was using the XKR-S ECU software, still well within the limits of the hardware.

[GeniusOfLove]

8bit said:

I didn't say "gently", but it is still possible to drive a remapped car with mechanical sympathy and enjoy the extra output from the engine. I've had mapped cars myself, driven them enthusiastically and never suffered the issues you have. If remaps were essentially a guaranteed way to kill a car, nobody would be buying them...

100% agree on the last paragraph though - I went from a 4.2 XKR to a 5.0 XKR and it was a much bigger leap in performance than I'd anticipated. I still remapped the 5.0 car though, but that was using the XKR-S ECU software, still well within the limits of the hardware.

I do pretty big mileages in most of my cars, I'm likely to find any weaknesses much sooner than someone doing 6k a year.

That's a very sensible way to remap the 5.0 s/c

I think it's quite telling that even in their VERY expensive Project 8 Jaguar got 600bhp from the AJV8 but tuners in sheds reckon they're getting more. That'll be a combination of Jaguar testing power to proper ISO 15550 standards and a tuner seeing a momentary peak and calling it, as Max_Torque used to say a tuner horse is worth about half an OE horse, and to Jaguar actually knowing what'll kill it and what won't.

Worth remembering that if the net crank power of a supercharged engine is 600bhp it's probably making close to 700bhp gross due to the crank power required to drive the charger. That AJV8 works damned hard.

May I ask who put the XKR-S ecu software on your car? I'm tempted to do the same for my Supersport, but I don't trust tuners an inch; I saw one of the best respected Jaguar tuners out there putting it about that there were no worries for the gearbox because Mercedes Benz use the same box in the 1000NM AMG V12 twin turbo cars, which is complete and utter bullst.

[8bit]

GeniusOfLove said:

I do pretty big mileages in most of my cars, I'm likely to find any weaknesses much sooner than someone doing 6k a year.

That's a very sensible way to remap the 5.0 s/c

I think it's quite telling that even in their VERY expensive Project 8 Jaguar got 600bhp from the AJV8 but tuners in sheds reckon they're getting more. That'll be a combination of Jaguar testing power to proper ISO 15550 standards and a tuner seeing a momentary peak and calling it, as Max_Torque used to say a tuner horse is worth about half an OE horse, and to Jaguar actually knowing what'll kill it and what won't.

Worth remembering that if the net crank power of a supercharged engine is 600bhp it's probably making close to 700bhp gross due to the crank power required to drive the charger. That AJV8 works damned hard.

May I ask who put the XKR-S ecu software on your car? I'm tempted to do the same for my Supersport, but I don't trust tuners an inch; I saw one of the best respected Jaguar tuners out there putting it about that there were no worries for the gearbox because Mercedes Benz use the same box in the 1000NM AMG V12 twin turbo cars, which is complete and utter bullst.

I suspect you've had a fairly sizeable helping of bad luck affecting your results too though. Who were you getting to map those cars, reputable companies or "specialists"?

I doubt anyone is genuinely getting much north of 600bhp out of the 5.0 S/C V8, not without significant hardware changes, and by that I mean uprating the supercharger. Plenty of folk on the US-centric Jag forum claiming 650bhp+ just with a "tune" and having uprated the intercooler coolant pump but nobody has genuine, independent dyno results to prove it.

I will PM you regarding the R-S software upgrade.

EDIT - looks like I can't PM you, pop me a message instead if you want to discuss