OK guys, maybe someone can help or has some thoughts on this;

I recently purchased a 2014 V8S (love it so far) and during the course of deciding which car to buy and later out of general interest, I believe I've read or watched virtually every F type road test or performance comparison out there!

Initially I was thinking of investigating the various software "tunes" available out there on the market with the intent of "flashing" my car up to current 2015/2016 550hp "R" standards as I understand that the actual engine and hardware is identical.

....the problem is that the more I read and watched, I've become less and less convinced that there is an actual 55 hp difference between the 2014 V8S hp output vs. the 2015/2016 R. The RWD vs. AWD skews things a bit by introducing superior traction for the AWD along with another 200lbs or so; comparing results to a 2015 type R RWD vs the 2014 V8S should be more "apples to apples".

So, what I found was that there is a huge discrepancy between various 0-60 and quarter mile times depending on who tested them and Jaguar's own ratings seemed very pessimistic compared to what's been tested. I also found that the best time I could find was the 3.4 0-60 and 11.6 @ 122mph test by Motor Trend on a 2014 V8S.....none of the 550hp cars seemed to do any better....Odd. The MT test also didn't seem to be completely out of place as Car & Driver did a 3.6 0-60 and an 11.9 @ 121mph on a similar V8S.
Trap speed is a better indicator of power than the ET due to traction constraints, especially on the RWD cars. I've not seen any quarter mile times for either engine with trap speeds above 122 mph.

MT dynoed the car and got 447 whp....which seems pretty high given the 495hp rating. They suggested it was probably underrated. A fellow on another forum did a similar dyno test (using a similar dyno) on a 550hp car got a 442 whp result leading the tester to suggest a 20% driveline loss. If the driveline losses are anywhere near 20%, then the V8S is producing quite a bit more than 495hp (at the flywheel). I am aware of the discrepancies between dynos and even between two identical cars so I'm not suggesting the S is MORE powerful....but still...

I also saw a comment in this forum that the V8S "typically" puts out 425 - 435hp.

So at the end of the day, I'm not convinced that there is a 55hp difference between the V8S and V8R engines. Is it a smaller number? how small? I don't know.

I don't raise this question to make myself feel good with my "less powerful" 2014, I raise it because I had planned on a software upgrade that I'm now not convinced is necessary or desirable.

Thoughts? Is Jaguar spot on with their ratings in both cases and the fact the 550hp cars aren't any faster has another explanation? Is there a difference but it's less than advertised or even is it just a difference on paper? Looking for objective comments (if possible) rather than people trying to justify what they bought....

Cheers,
Dave

 

link to MT's testing, including the dyno results;

 

Car and Driver on a 2016 Type R coupe;

http://www.caranddriver.com/comparis...e-specs-page-5

 

Just my humble opinion...


There are a considerable number of variables when testing for numbers, from one experience to the next.


Differences between identical spec cars, weather (temp. & humidity, etc.), altitude, testing machines and procedures, and the list goes on.


This car is probably "over-powered" for what it is, just as it comes stock from the factory.


Do a quick search and read on "VMax", (not to say all tuners are like this).


You already have a very fast and desirable car. If it were me, I would simply enjoy it as it came from the factory

 

Thanks. I agree that there are many variables (I'm no stranger to drag racing); but the data I've seen suggests that the 55hp difference is exaggerated at the very least and I'm just curious to find out more on the issue. I could write off one test or one dyno as an anomaly but there seems to be several corroborating pces of evidence to support the S and R being closer in output than Jaguar marketing would lead you to believe.

You're right; the car has lots of power and the wisest course of action is to leave well enough alone. I've read the Vmax threads.....enough said. Now I'm more inclined to leave the car as-is...especially since I don't think the R's have another 55hp anyway. ...it's mainly just curiosity at this point.



Dave

 

I have an opinion too!

I have a 2015 V8S and 495hp is plenty. Heck, I cannot push the happy pedal all the way down without considerable wheel-spin. Without an increase in traction would an increase in hp even mean anything?

 

Your point is well taken though yes, more power would still improve acceleration times even with the increased traction difficulties.

If you want to see traction issues check this out: F.A.S.T. - Factory Appearing Stock Tire - Home - The F.A.S.T. record holder runs a 9.84 @ 139.82mph on G60-15 biased ply tires! Compared to those, our 20" 295mm wide Pirelli P Zeros might as well be racing slicks! ...and of course those guys don't have traction or stability control either.



Cheers,
Dave

 

I agree to a certain extent but then again it all depends on the driver.
Old video but....

 

Congratulations on opening a can of worms

I have some experience with a V8S and have spent some time going through the factory data and tunes, here's my input.

1. The factory ratings for the cars are given in PS (Pferdestärke) which is metric horsepower. The V8S is "rated" 495PS = 488HP, the R is 550PS = 542HP. For whatever reason Jaguar North America has published the PS numbers as HP. It's splitting hairs, but something to keep in mind about numbers being fudged. (and they ARE being fudged)

2. The factory tune file for the V8S (the one that gets loaded into the car with the SDD diagnostic system by dealers) actually is marked "510PS" in the text header. So could it be that the V8S actually has a 510PS / 503HP "rated" output, same like the XFR, XKR, XJR, etc.. Yes I believe it does.

3. There is a considerable difference in the factory files/tunes between the V8S and the R, driving two different cars back to back the difference is quite apparent. They are not the same car nor the same power output.

4. The numbers from chassis dyno's should really be taken with a grain of salt. For example with my own XJR i've had it on three different dyno's, and had as much as a 40rwhp difference between the three. We also put a V8S on the dyno and it made "only" 414rwhp yet other V8S on other dyno's have made considerably more. Dyno numbers are not the be-all and end-all. Quarter mile traps are where it's at, but even then there are caveats...

5. Jaguar changed the wiring connections of the F-Type's ECU from 2014MY to 2015MY, for this reason it's not possible to simply flash an R tune into a V8S, the file needs to be modified for the change in wiring pinouts. "We" did this with a V8S and the results were impressive, and kind of embarrassing for some. Some info in this thread https://www.jaguarforums.com/forum/f...2/#post1342003

I suppose you've seen the dragtimes list? Fast Jaguar F-Types 1/4 Mile 0-60 Drag Racing - DragTimes.com of course not every car is on that list. The Hennesey for example. Also take note of which cars are stock, and which are tuned or with pulley.

With all the tuning that's gone on with the F-Type in the last couple of years, i find it a little strange that there are only five privately owned cars on the list. The rest are magazines...

6. And unless there is a timeslip from a track, don't believe what you read in magazines a friend of mine here in Australia who's an automotive journalist, and was editor of one of the bigger car mags down here for a while, once explained about the different testing methods "off the track"

7. Don't rule out factory press cars having "test" tunes in them. Not saying Jag did this, but it's not unheard of...

8. A number of 5.0L cars; F-Types, XFR, XKR have pulled some incredible "stock" numbers on the dyno which seem to beggar belief. Are some cars "freaks" from the factory? or to put it another way, are some actually dogs? I don't know. Are the factory numbers plucked out of the air? Yes I believe they are...

My 2 cents.

 

Was ready to provide an opinion, then looked at a few threads and realized I knew nothing. W bit disturbing that.
I have read the VelocityAP thread and seem to recall they have performed magic with VW's and have a good reputation. They are in the Lower Mainland. I'd be tempted to call them, chat, and then do a road trip if it looked promising.
Might I suggest 97 to the Apex turnoff at Penticton, Re-connect to 97 to Keremos, 3 to the shop.....or the Connector to the Princeton turnoff, take it and then 3 to Hope and the shop. Many happy miles in my 911SC and VFR 800 in times past. Looking forward to delivery of my Ammonite Grey R this week....and exploring the Maritimes with it

 

Just to back up Cam's last point (#8), I have a 2010 XFR rated at 375 KW or 510 PS, and when I put it on the dyno a few months ago it recorded 344.7 rear wheel KW (= 468.88 PS). Stock car other than for K&N air filters and after-market hi-flow mufflers, both of which in theory make little or no difference to top end power.
That's a supposed drivetrain loss of only 8%, which seems very low when on nearly all dynos the drivetrain loss for a RWD auto should be somewhere between 12% and 20%.
If I convert back the other way, and assume a drivetrain loss figure at the low end of 12%, I get 391.7 KW or 532.57 PS at the flywheel, which is 4.4% higher than the quoted stock figures.
So maybe mine did put out a bit more than the quoted stock figures, who knows!

 

Great post. Thanks.

 

Hmmm; your experience along with this enlightening item from Cam;

2. The factory tune file for the V8S (the one that gets loaded into the car with the SDD diagnostic system by dealers) actually is marked "510PS" in the text header. So could it be that the V8S actually has a 510PS / 503HP "rated" output, same like the XFR, XKR, XJR, etc.. Yes I believe it does.


coincides nicely with the theory that others have espoused claiming the V8S is pushing more power than stated.....if the SAME engine with the SAME tune in other cars is rated at more power then clearly something is "off". It's not unheard of in automotive marketing...

I'd also note that your RWHP was almost identical to the V8S MT dynoed. Given what Cam said about the tune file, that makes alot of sense.


Dave

 

Thanks for the suggestion (it's a nice drive) and have fun with your new car! :-)


Dave

 

Yes, and when I put the F-Type real-world weight and trap of 122mph into the usual calculators, it's much closer to 600hp than the 550hp...


Honestly I haven't had the chance to drive a 550ps and a 510ps car back to back either. But the gentleman who owns the V8S that we put the R tune into has. And after the tune went into his car he commented "it's just like the difference in the factory tunes" and the smile on his face confirmed it to be true.

As for the factory tunes being all over the place, here's a very interesting read https://www.jaguarforums.com/forum/x...vs-xfr-151960/

A stock XFR-S putting down 532rwhp on the dyno!?!? That's outrageous!

So at one end of the scale you have a "488hp" V8S making 414rwhp, and at the other a "542hp" XFR-S making 532rwhp. Try making sense of it, I can't.

 

There is another complexity with dynos of stock cars (for the 5.0SC ones), and those are the ECUs Torque limiters and the Dynos correction factors. Now if have not made any measurements, its only logic that I apply here.

The ECU will regulate the amount of power via the throttle based on engine torque, which it calculates from the airflow/temp (amongst others). So on a hot day, the throttle will be more open then on a cold day, so that in the end, the same max torque is reached.

Yet on a dyno, you normally get a correction factor calculated, being it SAE STD, NET or DIN, each will have its own correction method, which actually should not be done as it skews the recordings as the engine ECU has already adjusted the actual torque.

Just to complement all the comments already made, that you need to be careful when wanting to compare figures, even the DA calculation for the trap speed would not right for the stock cars. Only if all torque limiters have been removed from the ECU, you can use again the DA for trap speeds or correction factors for dynos.

 

A lot of good information in this thread - very interesting.

And another thing that I can't see has been addressed regarding max hp vs acceleration, is that two cars with identical max hp might have different acceleration times (and feel), a lot depending on mid range power and torque (which might be different even though max power is the same).

I do not know if there are any difference in mid range power and torque between a V8S and R, but if it is, it would also have an effect on acceleration times (and "butt feel"). Area under the "useable" part of the power and torque graph is what is most important in everyday use, and not just max power.

 

So it seems like the way to figure this out (at least relatively) is to have an S and and R dynoed on the same dyno right after each other. That won't give actuals, but would show the differences between the two, if any

 

Exactly. It's the same rationale for always doing a before and after dyno to determine a reasonably accurate impact of a tune.

 

Vmax tune?