Traction Issue SVR
#1
Traction Issue SVR
Hi all, new here and looking for a little advice. Just picked up a 2020 SVR and I’m finding it struggles a bit traction wise in the dry, 1st 2nd gear 70-80 degrees temperature. I’m no stranger to the F Type had a 2014 V8S and 2017 R and I don’t recall the R having traction issues at all, am I missing something? I’m also used to high horsepower cars (2 Hellcats, 2 RedEyes and multiple others) so I don’t think it’s user error. Any thoughts appreciated.
#2
Join Date: Feb 2014
Location: Adelaide, South Australia
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bk000 (05-18-2023)
#3
Yup, running P Zeros but less than 3,000 miles on them. I know on the RedEyes the P Zeros were junk but they were trying to cope with 800 bhp and over 700 lbs/ft of torque through 2 275s or 305s. My recollection of my R was no traction issues at all, the TC seems to kick in a lot on the SVR.
#6
Car rolling, rolling on tho accelerator quickly, not standing on it in first or second gear I get immediate response followed in a slit second by TC light and power being reduced until traction regained (typical TC intervention) I can live with it, I just remember my R being so much better. Point taken on Pirellis I was thinking this might be the problem, just wanted to see what others were experiencing before Intake it to the dealer to get TC looked or change tyres or lessen traction expectations and drive accordingly.
#7
Car rolling, rolling on tho accelerator quickly, not standing on it in first or second gear I get immediate response followed in a slit second by TC light and power being reduced until traction regained (typical TC intervention) I can live with it, I just remember my R being so much better. Point taken on Pirellis I was thinking this might be the problem, just wanted to see what others were experiencing before Intake it to the dealer to get TC looked or change tyres or lessen traction expectations and drive accordingly.
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#9
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#11
Yes, it's rear wheel biased, I've seen numerous publications that state 20% of the output can go to each front wheel (i.e. 40% front/60% rear), but I've also seen where they can actually split 50% front/rear (go figure - consistence on the internet?!). If I had to guess the splits are then proportional to the output. So much depends on the actuator authority (e.g. the limited slip rear differential has an 'actuator' that determines the split left to right). How much can the actuator vary the output and are the clutch packs actually limited on how much they will actually transmit per wheel? I've not studied the front to rear bias system - I think it's somehow managed by other actuated clutch packs for each front wheel.
So... my guess (again - not studied) - is that the outputs are proportional.
So... my guess (again - not studied) - is that the outputs are proportional.
#12
It's WAY rear biased compared to my Audi TT. The TT (quattro) is front biased and shifts power to the rear when slip is detected. I put in WaveTrac diffs front and rear, and can stomp on the power at any time and retain traction. Never a hint of over steer.
With the R, I have now spun three times, all accidently. All three in the wet. All three the rear end power sliding around. I need to get some track time to learn the car and get a feel for the driving dynamics. As it is now, I am actually scared to put the power down!
With the R, I have now spun three times, all accidently. All three in the wet. All three the rear end power sliding around. I need to get some track time to learn the car and get a feel for the driving dynamics. As it is now, I am actually scared to put the power down!
Last edited by mcphill; 05-21-2023 at 10:16 PM.
#13
As a side note, as I understand the traction control defaults to all torque to the rear tires UNTIL it senses other inputs (like tire spin, yaw, etc.)
#14
All AWD F-Types, whether they are Rs, SVRs, or any other models, are biased to 100% RWD. Power is added to the front only when traction is compromised.
#15
Yes, it's rear wheel biased, I've seen numerous publications that state 20% of the output can go to each front wheel (i.e. 40% front/60% rear), but I've also seen where they can actually split 50% front/rear (go figure - consistence on the internet?!). If I had to guess the splits are then proportional to the output. So much depends on the actuator authority (e.g. the limited slip rear differential has an 'actuator' that determines the split left to right). How much can the actuator vary the output and are the clutch packs actually limited on how much they will actually transmit per wheel? I've not studied the front to rear bias system - I think it's somehow managed by other actuated clutch packs for each front wheel.
So... my guess (again - not studied) - is that the outputs are proportional.
So... my guess (again - not studied) - is that the outputs are proportional.
"Operating on the torque-on-demand principle, the AWD system sends 100 per cent of the engine's torque to the rear wheels under normal driving conditions. This maintains the F-TYPE's rear-wheel drive handling characteristics and also reduces parasitic losses in the drivetrain.If the system determines that the rear wheels are approaching the limit of available grip the electronically-controlled centre coupling transfers torque to the front axle, improving traction."
https://media.jaguar.com/en-gb/news/...l-transmission
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#16
Here's straight from Jaguar:
"Operating on the torque-on-demand principle, the AWD system sends 100 per cent of the engine's torque to the rear wheels under normal driving conditions. This maintains the F-TYPE's rear-wheel drive handling characteristics and also reduces parasitic losses in the drivetrain.If the system determines that the rear wheels are approaching the limit of available grip you have spun.the electronically-controlled centre coupling transfers torque to the front axle, improving traction."
https://media.jaguar.com/en-gb/news/...l-transmission
"Operating on the torque-on-demand principle, the AWD system sends 100 per cent of the engine's torque to the rear wheels under normal driving conditions. This maintains the F-TYPE's rear-wheel drive handling characteristics and also reduces parasitic losses in the drivetrain.If the system determines that
https://media.jaguar.com/en-gb/news/...l-transmission
Doesn't seem predictive at all to me, all reaction and "too late". But I do have to get the car on the track soon to test that out for sure. I will say my incidents have been in the wet, so harder to control and earlier onset than in the dry.
#17
Like you, though, I have experienced the car completely lose the rear on tight corners at lower speeds with moderate throttle. My instinct was to let off the throttle and steer through it. It may be that adding throttle would pull the car through, but I'm just not that comfortable with the AWD system to try it out. I have not experienced the loss of the rear since switching out the P-Zeros.
#18
Couple weeks ago on a dry track, the R understeered, pronounced from corner entry to apex and exacerbated by trail braking however slight, and will still understeer from apex to exit under throttle. It needs to be driven more in a slow, point, then shoot fashion than carry appreciable speed into and through turns. When the track was wet (downpour), understeer was horrible and surprisingly weather mode (50/50 torque split) understeered more than in either normal or dynamic mode. On MPS4. Now looking to pull together a set of 275 and 315 in 19s, and later maybe KW HAS.
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mcphill (05-26-2023)
#19
Here's straight from Jaguar:
"Operating on the torque-on-demand principle, the AWD system sends 100 per cent of the engine's torque to the rear wheels under normal driving conditions. This maintains the F-TYPE's rear-wheel drive handling characteristics and also reduces parasitic losses in the drivetrain.If the system determines that the rear wheels are approaching the limit of available grip the electronically-controlled centre coupling transfers torque to the front axle, improving traction."
https://media.jaguar.com/en-gb/news/...l-transmission
"Operating on the torque-on-demand principle, the AWD system sends 100 per cent of the engine's torque to the rear wheels under normal driving conditions. This maintains the F-TYPE's rear-wheel drive handling characteristics and also reduces parasitic losses in the drivetrain.If the system determines that the rear wheels are approaching the limit of available grip the electronically-controlled centre coupling transfers torque to the front axle, improving traction."
https://media.jaguar.com/en-gb/news/...l-transmission
#20
Maybe it senses the fronts aren't spinning so sends a bit of power forward to get 'em rolling? It doesn't know it's on a dyno!