Hur översätta denna diff från USA till svenskt språk?

Vi har haft en originaldiff till Porsches G50/52 som enligt PowerHaus II i USA är en "stock limited slip differential, a multi-disc plate/clutch type or "Salisbury" limited slip as it's sometimes termed", kallas på svenska Lamelldiff.

Vi har en numera från samma firma en "torque bias differential", vad heter det på svenska?

citat:
"Salisbury" limited slip as it's sometimes termed", kallas på svenska Lamelldiff.

Salisbury diffbroms är i min värd en ramplamelldiffbroms.

citat:
"torque bias differential"

Är inte det typ en torsendiff??? (hmm jag och stavning )

Jo, precis, "torque bias" är momentfördelning, ungefär. Torsen, Quaife, True-Trac är väl några firmanamn på dylika.

/Gustaf

Så det heter Torsendiff?

Qvarnis skrev:

Så det heter Torsendiff?

Någonstans i bakhuvet har jag ett minne av att torsen skall vara kort för "torque sensitive" eller något i den stilen.. Kanske värt att googla på?

Jag skulle nog tolka torque bias som momentförspänning, något man även har i alldeles vanliga
lamell- & rampdiffar.

OT/nästan:

hos Toyota finns det ett tillbehör till min bil som heter 2-way lsd - vad betyder då detta ?

Uttrycket "Torque-biasing" brukar användas för snäckdiffar, dvs. Quaife och Torsen.

Dom som kör fort med sina 911:or tycker att denna variant inte är det bästa vid banrace (dock vid slalom) då den låser upp vid inbromsning så dom påstår att man får sämre stabilitiet vid broms. Vi hade en låång diskussion om detta förut, den finns kvar i arkiven.

KristianAE86 skrev:

OT/nästan: hos Toyota finns det ett tillbehör till min bil som heter 2-way lsd - vad betyder då detta ?

Det betyder att den är aktiv både vid gaspådrag och gasuppsläpp. 1-vägs funkar alltså som en öppen diff vid inbromsning. 1.5-vägs är ett mellanting som inte bromsar lika mycket som en 2-vägs utan att vara helt öppen vid inbromsning. Tanken är väl att komma ifrån nackdelarna från både 2-vägs och 1-vägs diffarna. Jag vet inte hur bra det funkar, men det är väl en fråga om vad det är för problem med bilen du vill komma till rätta med.

Torsen är ett varumärke som Porsche eller Ford...väl?

Funktionsprincipen är som beepbeep säger en "snäckdiff" eller kanske "drevdiff". Det är alltså inte lameller som "låser" diffen utan drev som samverkar/motverkar för att fördela kraften.

Även om orden "torque biasing" inte riktigt är begränsade till att beskriva att det är drev i diffen, så är de så de används på engelska.

/Gustaf

beepbeep skrev:

Uttrycket "Torque-biasing" brukar användas för snäckdiffar, dvs. Quaife och Torsen. Dom som kör fort med sina 911:or tycker att denna variant inte är det bästa vid banrace (dock vid slalom) då den låser upp vid inbromsning så dom påstår att man får sämre stabilitiet vid broms. Vi hade en låång diskussion om detta förut, den finns kvar i arkiven.

om jag inte översätter helt fel så låser den bara vid acc och inte vid broms. Så här skriver PowerHausII om diffen:

"The torque bias differential that you have now uses gears instead of
clutches to prevent wheel spin and is a function of torque input. The
internal gear design will determine the locking effect or "bias ratio". The
differential you use now has a 3:1 bias ratio or 75% lock. However this
design will only provide locking effect on acceleration and is not
adjustable-but you don't have to maintain it."

Så, vad kallas den?

Då är det definitivt en Quaife-diff. Torsen (R) och Quaife (R) diff jobbar med samma princip, det är bara att Quaife stoppade i några fler drev (antagligen för att kringgå patenten). Det är en snäckdiff av samma sort som sitter i mittdiffen på t.ex. en Audi Quattro.

Den låser upp helt och hållet när man lyfter från gasen/bromsar in eller när ena hjulet lättar från backen. Det som är bra med den är att den är underhållsfri samt att den inte producerar lika mycket värme.

Det som är dåligt är att den (enligt kunniga racers) inte är lika snabb på bana som riktig lamelldiff (speciellt rampdiffar som har olika låsningar beroende på om man gasar eller bromsar).


Citat från förra tråden:

Citat:

I think that you need to keep in mind that different diff's do different things in different situations. What the "Best" diff will be is the one that does what you want it to in the situations which most concern you. It's a mistake to think that one type is bad while another is good. It's strictly a "horses for courses" type discussion. Differential Modes to be considered: * What does the diff do when accelerating? How fast does it do it? How hard does it do it? * What does the diff do when deaccelerating? How fast does it do it? How hard does it do it? Some examples (based on a 911, FWD cars will react somewhat differently). Keep in mind there are 4 classes of diff's: open, limited slip, torque sensing or biasing and locked (which is actually no longer a differential!) Spool (solid diff): on acceleration the extra traction from the inside rear wheel tends to push the car into an understeering mode (pun intended). Obviously there is no transistion. On deacceleration, the outside rear wheel is normally the first to lose traction. With a spool the extra grip at the outside rear will tend to pull the car straight. Since the two rear wheels are locked together it is also harder to flatspot a rear tire with a locked rear end. 935's used them because it is very difficult to light up both rear wheels which was a problem with those high HP cars. Oval track cars use them because they have the car set-up with stagger (a larger rear wheel on the outside at the back) which helps the car through the turns. A good analogy is a styrofoam dixxy cup rolling on a table. One downside is that cars with spools are absolutely impossible to meneuver at low speeds or in the paddock area without tire dollys. An open diff: This is hands down the best solution for a street car. As long as both rear wheels are solidly on the ground, it will adjust according to each wheels speed. It runs into problems if one wheel (Usually the inside wheel) starts to spin under acceleration since it will overapply torque to that wheel based on its speed. On deaccelleration it allows each rear wheel to do its own thing. -- Limited Slip Differentials -- Salsbury, Plate or Clutchpack differentials: This is the OEM style diff for a 911. The amount that the diff will lock is based on four things: the cam angle, the spring pressure on the clutch pack, the clutch material and the order in which the clutches are put together. There are two ramp angles, one for acceleration and one for over-run (aka: coast). They are usually listed as numbers in tha order, like 60/30. The number represent the ramp angles and vary from 90 degrees (no locking affect) down to about 30 degrees (Very strong locking affect). BTW, no one uses a 90 degree ramp because they chip, the highest number that you will usually see is 85. A 60/30 diff will have moderate locking on acceleration (so as to not induce too much understeer) and a strong locking affect on overrun (to help keep the car straight under braking). The spring pressure on the clutches (sometimes called preload) will affect how quickly the diff locks in both directions. A loose pressure (say what Porsche describes as 25% diff) will be fairly gentle when locking. A high pressure (an 80% Porsche diff) will tend to lock more abruptly and if the tension is high enough, act almost like a locked diff. The clutch material affects the lock-up in a similar fashion to the spring pressure based on how grippy it is. The arrangement of the clutches will also affect how abruptly the clutch locks. If the clutches are arranged so that there is only 1 rubbing surface, there will be comparatively little locking affect. If the pack is arranged so that there are more rubbing faces, the locking affect will be greater. -- other types of limited slips -- The Cam & Pawl (aka: ZF style) and the Viscous differential (popular in Touring cars and sometimes F1 or CART). You'll rarely see these on 911's for various reasons. -- Torque Sensing and Self Locking Diff's -- Weisman, Torsen and Quaife's. These will actually allocate more torque to the wheel which can accept more torque. I'm not going to discuss the Weismans since they are not that common in teh Porsche world. Each design has some slightly different features. Torsens and Quaifes are infinitely variable gear driven diff's that take advantage of the fact that worm gears can efficiently transmit torque in one direction only -- in the other direction they generate huge amounts of friction. They work real well allocating torque up to the point when one side loses traction. Once one side loses traction, these diff's will just spin that wheel. One feature of these diff's is that the function in one direction only, usually under acceleration. Under deacceleration they function as open diff's. Their affect tends to be instantanious. As soon as you start to apply torque to a Torque biasing diff, you will start to generate an understeering affect as a result of the increased torque available to the inside wheel. Finally the "Detroit Locker". A Locker is a pretty blunt instrument. It locks solid when under accelleration and is open on over run. During long corners Lockers "ratchet" and lock/unlock repeatedly which can be disconcerting until you get used to it. * 1st Hand Examples I've raced cars with open, locked and Detroit Locker diff's and have come to the following conclusions: Locked Diff's: A lot of us have used these on karts. They tend to push and hop in slow turns until you start to pick up speed and generate slip angles. Once I'm up to speed, I generally don't give it a lot of thought. They tend to be predictable and go where they're pointed. They're also very solid when braking. A nice feature for endurance racing is the limp-home feature if one of the rear axles brake (assuming that it doesn't pitch you into a wall first!) open Diff's: Surprisingly, most road race cars use open diff's since the SCCA requires them in FF, FC, FV, S2 and SR. If the car has a low center of gravity and a wide track or a lot of downforce, it really isn't a big deal since the wheels are rarely off of the ground. In a sedan or production car (including 911's), this is not the case and it is not uncommon to spin the rear wheel in hairpins. While hardly a fatal flaw, it is slow. A Detroit Locker: I once raced one in an ITC car. It does feel a little funny when it ratchets around long corners (like the banking at NHIS) because the car feels like it's "walking" or alternating between slight understeer and slight oversteer. In the case of the hairpin, I found that it was difficult to balance the throttle since the ratcheting affect would get in the way. The best approach seemed to be total commitment - either off the throttle or full on and steer like crazy. Any sort of diff except for an open diff will tend to induce understeer. This is for two reasons: 1) Increased thrust from the inside (lightly loaded) wheel will tend to push the car straight. 2) The increased forward thrust on the car will tend to increase squat and induce front end lift. When the front end comes up, it will lose traction as the tires become unweighed. This is good in a car which has oversteer dialed in, but bad for a car which understeers to begin with. As a result you may need to change your suspension set-up after you have replaced an open diff with something else. Conclusions: Which is "best" will depend on the car, the course and the rules. For track racing, I'd use a clutch style since other ajustable styles (like a viscous or combinations) are beyond my budget. I could play around with the clutch preload and stack-up to get the amount of locking affect desired. If the car had a fairly high power/weight ratio I might just go for a spool since they're cheap and fairly fool proof. My pit crew would hate me because they really are a drag to move around in the paddock. For soloing I'd consider a Quaife since they tend to be one-size fits all. None of them are perfect solutions. In the professional world, the trick set-up is to combine 2 styles (usually a clutch type and a viscous coupling type) into one diff. This is neat since it can be ajusted on the fly by varying the pressure on the clutch packs and playing with the viscous coupling. This is how F1 drivers can adjust their diff settings on the fly. But a lot of them still use spools or normal clutch-style diff's. A final point to consider is that Quaifes generate all of their heat (read absorb HP) when they are doing the torque biasing thing. Limited slips on the other hand generate less heat when they are locked up then when they are open. A good reference is Carroll Smith's "Drive to Win", specifically chapter 19: The Racing Differential. To quote Smith (Page 7-36): "So which is best? Probably the viscous coupling. For those of us who do not have access to a developed viscous, as usual it's different horses for different courses. In the current environment, given a limited budget and a reasonable amount of HP, a steel cased Torsen would be my choice, simply because the unit is so effective, so benign in operation and so reliable - one less variable. Given a testing budget, I would do a back to back comparison between the Emco, the Xtrac Viscous and either the Xtrac, Salisbury or the Hewland Powr Flow. I would not be at all surprised to find that I ended up running different diff's for different types of courses. For sure I would be tailoring the Salisbury (clutch type) or Powr Flow to the type of circuit. With a severely limited budget and/or an inexperienced driver, I would probably elect to use a cam and pawl - no surprises. As always with any question having to do with vehicle dynamics, I reserve the right to change my mind without notice"

Torsen-diffen låser väl inte upp utan slutar väl förmedla kraft till tex ytterhjulet om innehjulet lämnar backen i en kurva...

Mao, man måste ha liiiite liiite bromsning/motstånd på båda hjulen för att den ska fungera optimalt.

Jag skulle tveklöst gå för en korrekt avstämd ramplamelldiff.
Quaifes lyckades inte heller rekomendera en diff som pallade med ordentligt med vrid (500Nm+) till en av teamets långloppsbilar. Vet inte om dessa diffar är mer kännsliga för stora moment dock eller om vi bara hade otur.

Så namnet är Torsendiff elr är det en Quaifediff?

Anledningen att vi valt just denna är på inrådan av en raceingenjör här hemma som efter att ha tagit del av de erfarenheter vi har av lamelldiffar föreslog denna. Vi har trots att vi pulat isär lamelldiffen ett antal gånger inte fått den att fungera, det har spunnit hejdlöst på innerhjulet som om det vore odiffat trots nyrenoverat och motorn bak Porsche 911. Vi har 960 Nm och det orkar tydligen inte hålla emot. Jag har testat den nya diffen på bana och tycker den fungerar kanon. Ska bli kul att köra den med nymoddat chassi iår. Tror det kommer göra väldigt stor skillnad i acc ur tvära kurvor.

Tack alla som engagerat sig.

Gå in och kolla på denna sida , phantomgrip.com, och se deras annorlunda diffspärr för endast ca: 2350 skr.

Caper

Jörgen Bock skrev:

Gå in och kolla på denna sida , phantomgrip.com, och se deras annorlunda diffspärr för endast ca: 2350 skr. Caper

du glömde en ironi-smiley

Qvarnis skrev:

Så namnet är Torsendiff elr är det en Quaifediff? Anledningen att vi valt just denna är på inrådan av en raceingenjör här hemma som efter att ha tagit del av de erfarenheter vi har av lamelldiffar föreslog denna. Vi har trots att vi pulat isär lamelldiffen ett antal gånger inte fått den att fungera, det har spunnit hejdlöst på innerhjulet som om det vore odiffat trots nyrenoverat och motorn bak Porsche 911. Vi har 960 Nm och det orkar tydligen inte hålla emot. Jag har testat den nya diffen på bana och tycker den fungerar kanon. Ska bli kul att köra den med nymoddat chassi iår. Tror det kommer göra väldigt stor skillnad i acc ur tvära kurvor. Tack alla som engagerat sig.

Vad jag har fattat så kom Torsen på idéen med snäckdiff först och patenterade den, sen gjorde Quaife en rövare och bytte typ antal drev och några detaljer (för att kringgå patenten). Med andra ord verkar dom på samma sätt.

Det är möjligt att ni har för mycket vrid för att lamelldiffen ska hålla, men vridet på hjulen avtar ju snabbare man kör. Båda konstruktioner har sina för- och nackdelar.