Does anyone have pictures of Toyota's rear suspension for Sweden/Monte and Mexico? I ask because a 1.5cm reduction on the rear, will greatly affect chassis agility, maneuverabilty and especially high speed stability.
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Does anyone have pictures of Toyota's rear suspension for Sweden/Monte and Mexico? I ask because a 1.5cm reduction on the rear, will greatly affect chassis agility, maneuverabilty and especially high speed stability.
It is not easy to talk about the wing mirror stays when we don’t know the specific tech rules regarding aero (remember form 400/01 WRC), which means the changes could have been provoked by having to comply with some initially grey area in the rules, which was then clarified or they could have come about as a result of evolution in the aero concept of the complete car, i.e. changes to the rear wing might have come as a package deal together with the mirror stays for example.Quote:
Originally Posted by sonnybobiche
Also wondering if anybody has any insight into the downforce figures the 2017 WRC cars produce (or has this already been discussed?) – I know this will be a well-guarded secret, but wondering if anybody has heard anything in conversation.
If I was to make a very wild guess on the numbers (which could be way way off the mark), I would maybe say 200kg (+/-50kg) at 150kph in tarmac trim, which would roughly equate to the downforce produced by the special track editions of the “hyper” cars and slightly above than that of the road versions of these cars. This number will also be slightly below what a Formula 3 car produces. Then of course we can expand the question to what the downforce numbers are in gravel spec :)
Why do they have to loose 1,5 cm travel on the rear?Quote:
Originally Posted by mozesii
At Monte Carlo it was found car did not meet regulation requirements. It was considered no competitive advantage was gained and TGR were given until Mexico to correct the error without penaltyQuote:
Originally Posted by Sulland
In other words they let them drive only because it was the first event for the new cars. Normally it's very clear disqualification.
There is competitive advantage. Probably could explain the constant TGR mention of trying out different setups.
Another indication how much of an amateur team they are in their current format.
Is max suspesiontravel specified in the regulations? If yes, why?Quote:
Originally Posted by KiwiWRCfan
Didn’t they solve the suspension issue before Sweden? Rallye Magazin news after MC said suspension should be fixed before Sweden and engine before Mexico. I don't remeber anyone reporting otherwise.Quote:
Originally Posted by KiwiWRCfan
http://www.motorsportforums.com/show...V)-2017/page38
Yes that form 400/01 is the bane of my existence. Why oh why do they feel the need to be secretive about the damn technical regulations?Quote:
Originally Posted by NickRally
For what it's worth I just asked craig scarborough on twitter what he thought of the mirror wings and he said they're probably lousy, very high drag and little downforce. So maybe they got rid of them for that reason.
An upgrade from "village" team.Quote:
Originally Posted by N.O.T
An amateur team that won a rally before the championship started in Mexico . . . . . .
you spelled worthless flop of nothingness wrongQuote:
Originally Posted by mozesii
C'mon this is a tech analysis thread but some of you start to play kindergarten games. Back to topic now, I really do not care to read who spelled wrongly etc.
I would really appreciate if we could return to tech stuff and leave nonsense to Bar talk thread. Thank you!
Sent from my ONEPLUS A3003 using Tapatalk
and Ford´s gearbox thing is indication of Professional Teams way to do things ?Quote:
Originally Posted by N.O.T
I didn’t find anything in English about the Toyota’s homologation issue in Monte so I did some kind of translations of key issues.
http://yle.fi/urheilu/3-9413001
- Se ensimmäinen asia liittyi auton mittoihin. FIA otti mitat hieman eri paikasta mitan auton pohjalevystä iskunvaimentimen yläpäähän. Siinä taisi olla jokin sentin heitto, ja se johtui lähinnä luokitustodistuksen tulkinnasta.
- The first thing related to the dimensions of the car. The FIA took the dimensions from a little different point from the base plate to the upper end of the shock absorber. There was a difference about one centimetre, and it was mainly due to the interpretation of the homologation form.
- Saimme tähän asiaan muilta tiimeiltä hyväksynnän, voimme osallistua Monte Carlo -ralliin ja korjaamme asiat jo Ruotsin osakilpailuun, Mäkinen täsmentää.
- We got the approval from the other teams for this issue, we can participate in the Monte Carlo - rally and we will fix things by the Swedish rally, Mäkinen explains.
- Toinen juttu oli imuventtiili, jonka alihankkijamme oli vahingossa koonnut neljästä osasta, kun pakoventtiili oli sääntöjen mukaisesti kolmesta osasta. Silläkään asialla ei ole mitään vaikutusta suorituskykyyn, sillä materiaalit olivat aivan sääntöjen mukaisia.
- Another thing was the intake valve which was accidentally assembled of four parts by the subcontractor, when the exhaust valve should consist of three parts according to the regulations. Even that don’t have any effect on performance, because the materials completely comply with the regulations.
Pientä närää aiheutti myös kansainvälisen autoliitto FIA:n halu muuttaa joitakin aerodynamiikkaosiin liittyviä sääntöjä viime hetkessä. lisäkustannuksia tuli usealle tiimille.
A slight resentment was caused by FIA's desire to change some of the regulations of aerodynamics parts at last minute. That caused additional costs for several teams.
http://www.ksml.fi/urheilu/Toyotassa...fbb2bfb207c983
Tieto Toyotan laittomista osista piti paikkansa, mutta Jari-Matti Latvala ja Juho Hänninen saivat lähtöluvan kauden ensimmäiseen MM-ralliin, koska asia oli etukäteen sovittu Kansainvälisen autoliiton FIA:n kanssa.
The information of Toyota’s illegal parts was true, but Jari-Matti Latvala and Juho Hänninen received permission to start the season in the first World Championship rally, because the matter was agreed in advance with FIA.
M-Sportin tallipäällikkö Malcolm Wilson antoi mielellään hyväksyntänsä Toyotan erityisluvalle.
– Me kaikki teemme virheitä, me mukaan lukien, joten totta kai hyväksyimme Toyotan erivapauden, koska sillä ei ollut vaikutusta auton suorituskykyyn, Wilson korosti.
M-Sport team boss Malcolm Wilson willingly gave his approval for Toyota's special permission.
- We all make mistakes, including us, so of course we adopted Toyota's dispensation, since it had no effect on the car's performance, Wilson stressed.
– Meillä oli eri näkemys mitasta, joka otetaan auton pohjan tasosta iskunvaimentajan yläpäähän. Se ero oli jotain 12 milliä. Toinen asia liittyi imuventtiilin valmistusmenetelmään. Kumpikaan asia ei vaikuta auton suorituskykyyn, Mäkinen vakuutti.
- We had a different view of the dimension, which is measured from car base level to the upper end of shock absorbers. That difference was something like 12 mm. The second case concerned the manufacturing process of the intake valve. Neither of these things do not affect the car's performance, Mäkinen assured.
FIA ja Toyota Gazoo Racing kävivät Yariksen korin luokituksen läpi jouluviikolla.
FIA and Toyota Gazoo Racing made the bodyshell homologation check of the Yaris during the Christmas week.
I dont know if it was mentioned before...
C3 has clearly different front suspension setup for gravel and tarmac;
- gravel.. https://pbs.twimg.com/media/C6vbR3DXAAInVgK.jpg
- tarmac (at 0:16) https://www.youtube.com/watch?v=tm0o...ature=youtu.be
Yes, it was mentioned already in this thread. The tarmac front strut is made in Fabia R5 way while the gravel one is more common type with angled and longer damper.
Hyundai R5 also has similar front strut body angleQuote:
Originally Posted by Mirek
Thanks, I have never noticed that. You are right.
http://www.autoklub.pl/news/foto/201...929_70977h.jpg
Quit interesting that Hyundai has opted for next to driveshaft mounting on R5 but WRC 17 still has on top of driveshafts mounting (at least based on the pictures I`ve seen)
I think Hyundai now are the only ones with on top mounting of all the WRC manufactorers.
Image of the Yaris from Rally Mexico reveals (possibly) yet another small Venturi tunnel - the design team appear to have come with a very interesting from aero point of view car.
Attachment 1291
3. Hyundai i20
Finally time for the Hyundai i20 – the car seems very fast and no doubt this is because the complete package is fast rather than one particular thing being exceptionally outstanding. On the floor aero side, it appears less aggressive overall than the Yaris, sitting somewhere between it and the Fiesta, though some features are possibly closer to the Yaris than the Fiesta.
Attachment 1292
Attachment 1293
Attachment 1294
Attachment 1295
Attachment 1296
To be continued in the next post...
Attachment 1297
Attachment 1298
At 1 we can see the diffuser transition point with maybe touch more gentle curvature than the Yaris (could be optical illusion though), which would suggests touch less pressure suction peak, but more forgiving and stable one, though once again this is more applicable to a circuit racer with very low ride height than a rally car. The diffuser appears less steeply inclined (2) than the Yaris, once again suggesting the design team has been after a bit more forgiving downforce, albeit potentially sacrificing some headline numbers. The quantity of strakes (3) is similar to the Fiesta.
An interesting feature of this car’s diffuser is the second curvature region (4) past the mostly planar middle part of the diffuser, which is unique to the i20. In my experience this hasn’t been very effective on a circuit racer, but maybe they tried to regain some of the headline numbers without causing too much peaky-ness. Or the whole diffuser arrangement could be a result of what they can package given road car components in this area (i.e. curved transition from floor, followed by flat-ish region followed by another curved section) in order to have a longer diffuser for the same exit height, see image below:
Attachment 1299
At 5, as already pointed out on this forum by Ctesibios, is the small but very aggressive Venturi channel ahead of the rear wheels – it is very steeply raked and I wonder if the air stays attached there, though ahead of the wheels, all sorts of amazing things happen. Nevertheless it is smaller than the one on the Yaris and its suction peak will be further rearwards.
The floor of the i20 appears relatively rough (6) to what I am used to, but maybe certain features can be used to benefit the aerodynamics, like the longitudinal railings. Either that, or the design team did not consider these components to be too penalising or of sufficient importance, to change the design direction from the traditional rally floors.
The offset exhaust (7) is embedded in the diffuser, once again feature unique to the i20 with all the other cars opting for central exhaust above the diffuser. I suspect they have done this for packaging, but I could be wrong. Nevertheless, the fact that the exhaust is embedded in the diffuser closer to its transition point from the floor, means its effect might be more powerful. Or, once again, it might just be a packaging exercise.
At 8 is a good view of the complete diffuser and its more square appearance relative to the Yaris with its gradual sides.
9 shows a mismatch between the two suspension guards in their sitting relative to the rest of the floor with the wheels in fool droop, presumably caused by road damage. Or, if the design was too optimistic, it might be that the actual suspension travel have distorted one of them. On another note, I wonder how much the curvature (10) of these guards helps aero downforce creation – I know they are not very rigid, but even so.
11 shows the lack of front Venturi channels, while 12 represents an interesting idea about potential duct, channelling air from underneath the car to the top surface.
Very nice read as usual :)
Educative
I am sure you have been wondering how long before I use the upside down image of the Yaris from Corsica (Hanninen’s unfortunate off), so here it is with few notes.
http://www.geocities.ws/rallytech/ae...is_aero_10.jpg
http://www.geocities.ws/rallytech/ae...is_aero_11.jpg
I have a question about center differentials on the new 2017 spec cars. How do they work exactly. The way I understand it the active center differential can be either open or locked and the state is hydraulically controlled with help of electronics. While locked, front and rear axles act as if there was no differential (like in previous models) and when it's open it acts like a front open differential on a regular road car, when one side loses grip then it spins out robbing the torque from other side. The active part lets it go between both states depending on the data from a number of sensors. The power split between the axles is 50/50 on WRC cars as far as I know (correct me if I'm wrong). Now what confuses me are the problems Ogier had faced in Rally Corsica. His hydraulics had failed and he ended up with a rear wheel drive vehicle. Shouldn't he had ended up with an open differential instead, since the hydraulics would be responsible for locking the center differential?
Hi Kris82, very valid point and one that has puzzled me too. Assuming what was said about ending with rear wheel drive only as a result of the problem is correct (which is by no means certain), then maybe the centre diff on the Fiesta is not of the usual epicyclic gear type with clutch pack to vary the degree of locking, but maybe it uses two clutch packs each controlling the flow of torque to the front and rear axles. This would permit infinite degree of variability in the proportion of torque send to the front and rear axles. I am not sure how reliable such device on a current WRC car will be, but to the best of my knowledge it is used on the current Focus RS to distribute the torque between the two rear wheels in place of the usual epicyclic type rear differential.
I need to watch the footage from the first Sunday stage (only seen the power stage so far) and see if Ogier’s car really behaves like a rear wheel drive one and if the statement to that effect is likely to be correct or just an expression by a frustrated driver (if of course my memory is correct and it came from Ogier).
Regards,
Nick
Interesting interview with Mads Ostberg including quite a bit about the 2017 car's active centre diff, plus the info from M-Sport not being shared with Mads team...
https://www.podbean.com/media/share/pb-qu8kn-69e93e
I don't think that is any chance to have just 2 clutch packs and not epicyclic gear type center diff.Imho such application will not be reliable and capable at wrc level,its almost not reliable at street cars(focus rs)Quote:
Originally Posted by NickRally
no they are not just ''opened'' or ''locked''Quote:
Originally Posted by Kris82
they can be opened.locked,and semilocked at countless theoretically positions depenting if you are at a corner,at brakes,if you are with steering at straight or some degres left/right ,the gas pedal position etc.
Doesn't seem like the Focus RS is a car you would use on an ice track all day, some diff problems in this video from Team O'Neil.
https://www.youtube.com/watch?v=F33BQEXBvok
Ostberg was saying that although he has previous experience driving active-diff cars, this has not really helped him with the 2017 Fiesta as it a brand new car and there are so many variables to adjust.
He confirmed his car can be 'faster' with the centre diff locked (with better traction), but this also makes the Fiesta more difficult to drive especially setting it up for corners. His team are keeping his car set-up as 'simple' as possible as its impossible to adjust too many settings and know which is actually improving the car's performance.
The center differential very likely has a clutch that operates with hydraulic pressure that locks the differential. That means that when there is no hydraulic pressure, the power is sent to where there is the least grip. As the car accelerate, the front lift and the power spins away on the front wheels. That means only the rear wheels have grip which is probably why he had to drive it like a rear wheel drive car.
That's my take on the dynamics anyway.
I know there is open and locked and everything in between. I hadn't said it clearly, or you overanalyzed what I had said. :)Quote:
Originally Posted by dimviii
That's what I was leaning towards as well. I was just confused by what Ogier and one of the commentators before him (if I remember correctly) had said during the coverage.Quote:
Originally Posted by itix
Locked center diff = natural understeering, i.e. slower car everywhere except full acceleration on straight and a car which needs to be driven more sideways to turn.Quote:
Originally Posted by Fast Eddie WRC
No expert here but that makes little sense to me. With opened differential You can't have more torque on one side than on the other. The side with less grip determins the torque going to the other, i.e. the lesser grip on one side the lesser torque the whole system brings but the split ratio is not changed. In extremum when You lift one complete axle it spins but the other stands still as there is no torque on the other side except mechanical friction.Quote:
Originally Posted by itix
Correct me if I'm wrong.
You are spot on Mirek. I think that is what itix meant but you described it better. The thing is that in that situation the front would spin out hence making it feel more like a front wheel drive car. I guess in the end the car feel would depend on how the front and rear diffs were set up.
I like Focus RS system, because it can do centre and rear diff work only with two clutches (very good price performance solution). But it is actually a FWD car meant to be pushed just here and there for a little while. Still it cant do more than locked diff...
More options has EVO X (if I am not wrong) rear diff, that can accelerete one wheel over the speed of locked diff. But I see no need for such system in a WRC, because it is just a compensation for poor drive skills (it make turn car faster than driver can perform by his own pedal/steering work).
In WRC I think there is no more than a diff with clutch, that can be opened locked or everything in between. It means that it performs at equal for both axles (open) or equal speed (if no gearing is involved) for both axles (locked) or in between.
Regarding Ogires RWD feel... I think it can happen if he had a front diff problem, so that front diff remains open. It means that front axle had just as much torque transfer as the "less grip wheel" allows i.e. less than usual. It means that most of the torque went trough rear wheels.
You wouldn’t be able to send more torque to the rear wheels (relative to the front) with an open centre diff as explained by Mirek, the only difference opened or locked front diff will make is to provide “the least common denominator” for the whole transmission system, i.e. the path of least resistance or in other words the max torque that can be transmitted through the system.
Looking at it from another angle (which might be what you meant), the combination of open centre diff, open front diff and some state of locking on the rear diff is likely to make the car more stable, i.e. give degree of understeer in general. Whether such comination will make the driver think or feel he has something akin to a rear wheel drive car, don’t really know, might be possible.