BHP and Torque - Page 2
Hello and welcome to our community! Is this your first visit?
Register
+ Reply to Thread
Page 2 of 4 FirstFirst 1234 LastLast
Results 21 to 40 of 64

Thread: BHP and Torque

  1. #21
    Very Active Member
    Join Date
    9th Jan 2015
    Location
    Ploiesti, Romania
    Posts
    271
    Dave, this is exactly my point. To bad I'm experiencing with the new power and torque in winter time directly. Actually my car was fine in late summer then the crack in the cam cover didn't leave me to use the car more than like a taxi car for a couple of months and after that, still being used to slow car bang, a lot more power (almost 40% increase). And the problem is when overtaking because you also need to change the direction quickly in a left-right (or for UK right-left) maneuver.

    Activated the Winter Mode while coming back home today (less than 5 Km in town driving) and the feeling was awful. Revving more but less power at the wheel, like a manual gearbox with faulty clutch. I'll probably return back to normal next days and try to train may right foot to be more gentle.

  2. Remove Advertisements
    JagInfo.org
    Advertisements
     

  3. #22
    Senior member Shrek's Avatar
    Join Date
    1st Nov 2012
    Location
    Midlands
    Posts
    3,311
    First name
    Neill
    Quote Originally Posted by Ancill View Post
    I used to have to use the 'loud pedal' with caution when overtaking on a cold damp day in my remapped XFR, when going over the camber, your brain wants you to floor the throttle to get past quickly, but in reality, you have to feather the accelerator
    Oh yes!
    Alaskan Racing White XFR-S with full carbon, and most other extras.
    Previous. IRR XFS Portfolio
    Previous. Stratus Grey XFS Portfolio

  4. #23
    Super Moderator wilf's Avatar
    Join Date
    3rd Jul 2012
    Location
    Leicestershire
    Posts
    18,844
    Oh, those days of worrying about the rear end stepping out are soooooo behind me. 4WD is where it is at for wet road traction! I simply love giving the RRS the full beans on roundabout exits these days. Little else keeps up with me in that situation.
    XF replaced by a big tractor due to intransigence of Jaguar marketing. A V6 engine and a Portfolio interior are now mutually exclusive if you live in the UK, but not elsewhere.

    Old lives matter!

  5. Remove Advertisements
    JagInfo.org
    Advertisements
     

  6. #24
    Executive Member Ancill's Avatar
    Join Date
    16th Oct 2012
    Location
    Peterborough
    Posts
    18,804
    First name
    Dave
    Quote Originally Posted by hulubei View Post
    Dave, this is exactly my point. To bad I'm experiencing with the new power and torque in winter time directly. Actually my car was fine in late summer then the crack in the cam cover didn't leave me to use the car more than like a taxi car for a couple of months and after that, still being used to slow car bang, a lot more power (almost 40% increase). And the problem is when overtaking because you also need to change the direction quickly in a left-right (or for UK right-left) maneuver.

    Activated the Winter Mode while coming back home today (less than 5 Km in town driving) and the feeling was awful. Revving more but less power at the wheel, like a manual gearbox with faulty clutch. I'll probably return back to normal next days and try to train may right foot to be more gentle.
    The remap should ensure that the throttle response is linear, with it being supercharged, I would expect this, however, with your car being remapped and a pulley, it will be close on 600bhp, which is a lot in a near 2 ton car with only the rear wheels putting the power down

  7. #25
    Executive Member Ancill's Avatar
    Join Date
    16th Oct 2012
    Location
    Peterborough
    Posts
    18,804
    First name
    Dave
    Quote Originally Posted by wilf View Post
    Oh, those days of worrying about the rear end stepping out are soooooo behind me. 4WD is where it is at for wet road traction! I simply love giving the RRS the full beans on roundabout exits these days. Little else keeps up with me in that situation.
    Must admit, I would like a car (not a tractor) with AWD next

  8. #26
    Quote Originally Posted by hulubei View Post
    Dave, this is exactly my point. To bad I'm experiencing with the new power and torque in winter time directly. Actually my car was fine in late summer then the crack in the cam cover didn't leave me to use the car more than like a taxi car for a couple of months and after that, still being used to slow car bang, a lot more power (almost 40% increase). And the problem is when overtaking because you also need to change the direction quickly in a left-right (or for UK right-left) maneuver.

    Activated the Winter Mode while coming back home today (less than 5 Km in town driving) and the feeling was awful. Revving more but less power at the wheel, like a manual gearbox with faulty clutch. I'll probably return back to normal next days and try to train may right foot to be more gentle.
    If you're having the back end sliding when overtaking and pulling in/out of traffic in a 300bhp car then I'd probably be questioning your driving style

    Try giving yourself more room to overtake, use the 2 second rule correctly and accelerate more smoothly.

  9. #27
    Very Active Member
    Join Date
    9th Jan 2015
    Location
    Ploiesti, Romania
    Posts
    271
    Probably I'm driving for some time like owning a Corsa but my question, is it probably to much when at 60 mph in straight line, if I firmly press the throttle the DSC to blink? Winter time here with BFG g-Force Winter 2 brand new on rears.

  10. #28
    Executive Member Ancill's Avatar
    Join Date
    16th Oct 2012
    Location
    Peterborough
    Posts
    18,804
    First name
    Dave
    Quote Originally Posted by hulubei View Post
    Probably I'm driving for some time like owning a Corsa but my question, is it probably to much when at 60 mph in straight line, if I firmly press the throttle the DSC to blink? Winter time here with BFG g-Force Winter 2 brand new on rears.
    The torque of the diesel is immense and available at low revs, high bhp is usually better as it's generally higher in the rev range

  11. #29
    Active Member Madart's Avatar
    Join Date
    4th Jan 2016
    Location
    Shot Gun Shack Queensland
    Posts
    207
    First name
    Mark
    I have a question about the traction control. I have the standard 3.0D (soon to be chipped to approach S figures) which I'm looking forward to- apart from if it doesn't improve the turbo lag.

    Last few days it's been raining after a long dry spell which makes the roads really slick as the oil build up mixes with the rain. The turbo lag in D seems most noticeable when accellerating from low speed (like onto a HWY on ramp) just when you need it to hook up well (and looking over your shoulder to merge). So yesterday the back end was very loose indeed in those situations where the foot is down and it lags then cuts in.
    Not having track tested the TC how far does it let the back step out before it cuts in? I was constantly getting the back end out 30 degrees yesterday and backing off slowly to control it.

    (you European guys are much better drivers in bad conditions than us fair weather drivers I think)

  12. #30
    Active Member etypephil's Avatar
    Join Date
    2nd Jan 2017
    Location
    Colchester, Fougeres, Budapest.
    Posts
    185
    First name
    Phil
    One can never have too much brake horsepower, nor torque, one can however, lack the wisdom to use them appropriately. Tyres and driving style are the primary factors, the electronic aids are there to assist, not as a substitute for driving skills. The XFR, with its remap and small supercharger pulley has almost 600 bhp and more than 700 Nm of torque, fitted with Nokian Winter tyres for the sub ten degree season, is easy to drive sanely, or when getting a march on.
    XJ V6 3 l, XFR 5 l. Past: XF V8 4.2 l, XJ12 6 l, Sovereign 4 l, XJS, XJC 4.2 l & 5.3 l convertibles, S1 & S2 XJ6 / 12 saloons, Mk 9 3.8 l, Mk 10 3.8 l, 420G, 3.8 l E type powered special, 3.8 l E types, Mk 2 3.4 l & 3.8 l saloons.

  13. #31
    Very Active Member phil200tdi's Avatar
    Join Date
    15th Aug 2014
    Location
    Aylesbury, UK
    Posts
    478
    Quote Originally Posted by Ancill View Post
    The XFR has an active diff, which in my experience in poor road conditions, makes it more of a handful.

    On a flat car park, you cannot floor the throttle and maintain a straight line, the active diff promotes fishtailing until it spins
    It's on exiting a corner in low grip situations that I feel the most benefit of the LSD - there is far more traction and any slides are more controlled..

    Mine will light up both rears at upto 70mph if I'm being silly. But the car tracks straight and true. Maybe the Dsc was interfering to make your car spin?

  14. #32
    Super Moderator wilf's Avatar
    Join Date
    3rd Jul 2012
    Location
    Leicestershire
    Posts
    18,844
    Funny.

    I used to campaign for open diffs on road cars, LSD on race cars. The reason is simple - with an open diff, the wheel with insufficient grip (usually the inner because of weight transfer) will spin up and stop torque being fed to the other wheel, which then has reserves of lateral grip. So the back end tends not to step out due to driveline torque.

    In a low friction situation, a LSD will almost guarantee that both rear wheels lose lateral grip and therefore the back end will move out.

    Now this is mainly to do with mechanical LSDs like the Jag ones I played with in the Cobra (lots of de-rating experiments etc.), not sure how it translates with brakes being used to feed torque across axles, but I suspect the effect is the same.

    I ended up running an open diff in the Cobra - not good for laying "11s", or accelerating out of corners on dry grippy surfaces, but I never disappeared through a hedge backwards in poor conditions like those with LSDs frequently did, usually on the exit of corners. And if the monster torque of that V8 broke traction while accelerating in a straight line, it didn't "snake" half as badly.
    Last edited by wilf; 5th January 2017 at 07:45.
    XF replaced by a big tractor due to intransigence of Jaguar marketing. A V6 engine and a Portfolio interior are now mutually exclusive if you live in the UK, but not elsewhere.

    Old lives matter!

  15. #33
    Executive Member Ancill's Avatar
    Join Date
    16th Oct 2012
    Location
    Peterborough
    Posts
    18,804
    First name
    Dave
    Quote Originally Posted by wilf View Post
    Funny.

    I used to campaign for open diffs on road cars, LSD on race cars. The reason is simple - with an open diff, the wheel with insufficient grip (usually the inner because of weight transfer) will spin up and stop torque being fed to the other wheel, which then has reserves of lateral grip. So the back end tends not to step out due to driveline torque.

    In a low friction situation, a LSD will almost guarantee that both rear wheels lose lateral grip and therefore the back end will move out.

    Now this is mainly to do with mechanical LSDs like the Jag ones I played with in the Cobra (lots of de-rating experiments etc.), not sure how it translates with brakes being used to feed torque across axles, but I suspect the effect is the same.

    I ended up running an open diff in the Cobra - not good for laying "11s", or accelerating out of corners on dry grippy surfaces, but I never disappeared through a hedge backwards in poor conditions like those with LSDs frequently did, usually on the exit of corners. And if the monster torque of that V8 broke traction while accelerating in a straight line, it didn't "snake" half as badly.
    Wow Wilf, two agreements in one day, let's not make too much of a habit of it

    The XFR is further exacerbated with it being an 'active diff' and not just an LSD, in my experience on the road, this made over correcting even worse

  16. #34
    Executive Member Ancill's Avatar
    Join Date
    16th Oct 2012
    Location
    Peterborough
    Posts
    18,804
    First name
    Dave
    Quote Originally Posted by phil200tdi View Post
    It's on exiting a corner in low grip situations that I feel the most benefit of the LSD - there is far more traction and any slides are more controlled..

    Mine will light up both rears at upto 70mph if I'm being silly. But the car tracks straight and true. Maybe the Dsc was interfering to make your car spin?
    The XFR has more than just an LSD and can create problems on the road where driver correction is enough, this coupled with an auto box can get things out of control very easily.

    The dsc does rein things in quite quickly if your grave enough to let it 'do its thing' and not intervene with any correction when facing a back end slide

  17. #35
    Super Moderator wilf's Avatar
    Join Date
    3rd Jul 2012
    Location
    Leicestershire
    Posts
    18,844
    Can't do that, it is an automatic reaction for me to steer into a slide. Had some really "exciting" moments in the XF with the DSC plus my own inputs amounting to over correction.
    XF replaced by a big tractor due to intransigence of Jaguar marketing. A V6 engine and a Portfolio interior are now mutually exclusive if you live in the UK, but not elsewhere.

    Old lives matter!

  18. #36
    Rampant Member MajorTom's Avatar
    Join Date
    23rd Jun 2013
    Location
    A tiny country in the middle of Europe
    Posts
    1,232
    First name
    Tom
    I'm driving an XFS remapped to about 320hp and 700Nm since a few years. No problems and the car certainly didn't get more jumpy after the remap, because the power is delivered in a linear manner.

    It does let go a bit sometimes when it's wet and I give it the beans, but that's never a surprise and it's always a pleasure to see how well the DSC manages things especially when comparing to what can happen with aggressive driving without the DSC (had the pleasure of a 180 degree spin with summer tyres on a dry summer road once ). Even with all that power I see the XF as very relaxing, reliable and predictive (with the electronic nannies on mind you)! I had an A6 before it and in comparison that car felt so unreliable in the winter... endless understeer all the time even at low speeds.

    Anyways, as others have mentioned, much depends on the quality and state of the tyres as well as the driving style.

    Perhaps your chip tuning messed things up by applying too much boost pressure at too low revs. Some time ago we had an interesting thread on here about remapping and there was a horror example of some really badly executed remap with loads of boost pressure applied at almost idle... certainly making the car extremely stressful and explosive and probably killing the engine and transmission in no time.
    Remapped XFS Portfolio with quite a few extras and a couple of mods

  19. #37
    Very Active Member
    Join Date
    9th Jan 2015
    Location
    Ploiesti, Romania
    Posts
    271
    I have no clue about the mapping. I just can hope it was a good one after so many years the engine is on the streets. It was a local saying he sends the file in Hungary to have the map modified. I don't know the truth but the map was back in like 30 mins to flash the ECU. I just can hope it's a good and reliable map.
    Probably is my driving style, most of time so so boring because of my "copilot" who brakes two times more then I do from the other side (she's all the time like a scared cat, so hard to got used to her but heh). And also probably the car is transformed from too much and also the weather don't help at all for traction.
    With all the notes from here, I'll come back in summer and see then how it feels. Thanks all for your opinions.

  20. #38
    Rampant Member
    Join Date
    28th Sep 2013
    Location
    Her Majesty's Glorious Midlands
    Posts
    1,271
    First name
    Ben
    As someone pointed out to me when I used to ride fast bikes...

    "The throttle goes two ways".

  21. #39
    Executive Member Ancill's Avatar
    Join Date
    16th Oct 2012
    Location
    Peterborough
    Posts
    18,804
    First name
    Dave
    Quote Originally Posted by bensales View Post
    As someone pointed out to me when I used to ride fast bikes...

    "The throttle goes two ways".
    Indeed, but there is no torque on a bike lol, this conversation is more about power delivery, not how far you plant your foot

  22. #40
    Rampant Member
    Join Date
    28th Sep 2013
    Location
    Her Majesty's Glorious Midlands
    Posts
    1,271
    First name
    Ben
    Quote Originally Posted by Ancill View Post
    Indeed, but there is no torque on a bike lol, this conversation is more about power delivery, not how far you plant your foot
    Not strictly true. My GSXR had 103Nm torque and 160bhp at the rear wheel, and weighed 213kg wet. So that's a power to weight ratio of 0.75 and a torque to weight ratio of 0.48.

    An XFR has 680Nm torque and 500bhp, and weighs 2370kg. So that's a power to weight ratio of 0.21 and a torque to weight ratio of 0.28. Positively weedy in comparison :-)


 

Quick Reply Quick Reply

Register Now

Please enter the name by which you would like to log-in and be known on this site.

Please enter a password for your user account. Note that passwords are case-sensitive.

Please enter a valid email address for yourself.

Please select your insurance company (Optional)

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.


Posting Permissions

  • You may post new threads
  • You may post replies
  • You may not post attachments
  • You may not edit your posts
  •