1-Way Front LSD Options
Aug 28, 2019, 08:14 PM
#1
1-Way Front LSD Options
The only options I see for 1-way clutch type front differentials is the Cusco LSD 450 C & the ATS Carbon Hybrid ??. The part numbers are iffy for the ATS, English translations aren't very good, and can't tell where to purchase from or how much.
Anyone able to chime in here on which they got? This is housed in the t-case, but shares fluid with the transmission? also, what temps do transmissions typically see? more looking at the racing side, ats says the carbon will chip at 300F+..
Anyone able to chime in here on which they got? This is housed in the t-case, but shares fluid with the transmission? also, what temps do transmissions typically see? more looking at the racing side, ats says the carbon will chip at 300F+..
Last edited by kyoo; Aug 28, 2019 at 08:44 PM.
Aug 29, 2019, 08:20 AM
#2
You aren't likely going to find many if anyone who can claim to have tried both. I think I know of 2 people who have tried more than 1 after market diff. Me trying both clutch and torsen, and Grice trying a bunch between Berry-mobile and some other local SoCal evos.
Im still on clutch (the unavailable Mfactory 1way) and Grice back on the Cusco. IIRC, he told me once something about one of the reasons they stuck with the Cusco is they cant kill it. Clutch discs after a few years still looked new.
Im going to pull the my full drivetrain this winter and inspecting the clutch discs is one of my tasks. If they look worn I'll decide if I want to make the jump to the Cusco diff. Ignoring money, I see no reason to not run that one at this point.
Im still on clutch (the unavailable Mfactory 1way) and Grice back on the Cusco. IIRC, he told me once something about one of the reasons they stuck with the Cusco is they cant kill it. Clutch discs after a few years still looked new.
Im going to pull the my full drivetrain this winter and inspecting the clutch discs is one of my tasks. If they look worn I'll decide if I want to make the jump to the Cusco diff. Ignoring money, I see no reason to not run that one at this point.
Aug 29, 2019, 03:05 PM
#5
I'll chime-in...
Grice told me a while ago that he used Cusco becasue he broke everything else, not because it was the best for the job in terms of laptimes / speed through corners.
I cannot remember specifically, but he virtually made me think that you want a "transparent" front LSD, like Wavetrac, ideally. Especially for track-application.
Meaning, clutch-type may have benefits on many slower-tight corners such as AX,
But on big-track like VIR, Willow Springs, Buttonwillow, you want smooth and transparent to avoid understeer.
Food for thought.
Grice told me a while ago that he used Cusco becasue he broke everything else, not because it was the best for the job in terms of laptimes / speed through corners.
I cannot remember specifically, but he virtually made me think that you want a "transparent" front LSD, like Wavetrac, ideally. Especially for track-application.
Meaning, clutch-type may have benefits on many slower-tight corners such as AX,
But on big-track like VIR, Willow Springs, Buttonwillow, you want smooth and transparent to avoid understeer.
Food for thought.
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Driv200 (Dec 17, 2020)
Aug 29, 2019, 03:09 PM
#6
I'll chime-in...
Grice told me a while ago that he used Cusco becasue he broke everything else, not because it was the best for the job in terms of laptimes / speed through corners.
I cannot remember specifically, but he virtually made me think that you want a "transparent" front LSD, like Wavetrac, ideally. Especially for track-application.
Meaning, clutch-type may have benefits on many slower-tight corners such as AX,
But on big-track like VIR, Willow Springs, Buttonwillow, you want smooth and transparent to avoid understeer.
Food for thought.
Grice told me a while ago that he used Cusco becasue he broke everything else, not because it was the best for the job in terms of laptimes / speed through corners.
I cannot remember specifically, but he virtually made me think that you want a "transparent" front LSD, like Wavetrac, ideally. Especially for track-application.
Meaning, clutch-type may have benefits on many slower-tight corners such as AX,
But on big-track like VIR, Willow Springs, Buttonwillow, you want smooth and transparent to avoid understeer.
Food for thought.
1-way Clutches will be open on turn-in, which will allow for the best turn-in compared to helicals, etc. The question becomes how they engage on power. WIth lower ramp angles and less clutch packs engaged, should still behave ok without any 1-tire fires, at least at my power level
Aug 29, 2019, 11:50 PM
#7
Frankly, I don't have "loss of traction" under power, I have understeer under power. That is not "the same thing", the two conditions, although a FWD w/o LSD may loose traction on inside wheel and understeer at the same time, as can/will Evo without front LSD.
In our case with LSD, until we overpower Torsen or Wavetrac, we have traction.
But we all have understeer, more pronounced by stiffer rear LSD. This is where AYC helps - torque vectoring outside wheel, rotating chassis, eliminating understeer -but AYC is non-OEM in USDM Evo, and we all hear its a bit non-linear and incosistent at high-power high- grip.
So maybe its the rear LSD that needs to be Spot On, and front- for track Torsen works awesome in Acura/Honda cars. Why not in Evo?
Ask any HOnda racer, and they are all quiet delighted by Torsen type LSD.
I suspect Andy's feedback of suddenly improved traction and killing understeer after going ATS, may be because rear LSD more so than front LSD.
Something to ponder, rear LSD sorting understeer.
In our case with LSD, until we overpower Torsen or Wavetrac, we have traction.
But we all have understeer, more pronounced by stiffer rear LSD. This is where AYC helps - torque vectoring outside wheel, rotating chassis, eliminating understeer -but AYC is non-OEM in USDM Evo, and we all hear its a bit non-linear and incosistent at high-power high- grip.
So maybe its the rear LSD that needs to be Spot On, and front- for track Torsen works awesome in Acura/Honda cars. Why not in Evo?
Ask any HOnda racer, and they are all quiet delighted by Torsen type LSD.
I suspect Andy's feedback of suddenly improved traction and killing understeer after going ATS, may be because rear LSD more so than front LSD.
Something to ponder, rear LSD sorting understeer.
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Aug 30, 2019, 06:59 AM
#8
Frankly, I don't have "loss of traction" under power, I have understeer under power. That is not "the same thing", the two conditions, although a FWD w/o LSD may loose traction on inside wheel and understeer at the same time, as can/will Evo without front LSD.
In our case with LSD, until we overpower Torsen or Wavetrac, we have traction.
But we all have understeer, more pronounced by stiffer rear LSD. This is where AYC helps - torque vectoring outside wheel, rotating chassis, eliminating understeer -but AYC is non-OEM in USDM Evo, and we all hear its a bit non-linear and incosistent at high-power high- grip.
So maybe its the rear LSD that needs to be Spot On, and front- for track Torsen works awesome in Acura/Honda cars. Why not in Evo?
Ask any HOnda racer, and they are all quiet delighted by Torsen type LSD.
I suspect Andy's feedback of suddenly improved traction and killing understeer after going ATS, may be because rear LSD more so than front LSD.
Something to ponder, rear LSD sorting understeer.
In our case with LSD, until we overpower Torsen or Wavetrac, we have traction.
But we all have understeer, more pronounced by stiffer rear LSD. This is where AYC helps - torque vectoring outside wheel, rotating chassis, eliminating understeer -but AYC is non-OEM in USDM Evo, and we all hear its a bit non-linear and incosistent at high-power high- grip.
So maybe its the rear LSD that needs to be Spot On, and front- for track Torsen works awesome in Acura/Honda cars. Why not in Evo?
Ask any HOnda racer, and they are all quiet delighted by Torsen type LSD.
I suspect Andy's feedback of suddenly improved traction and killing understeer after going ATS, may be because rear LSD more so than front LSD.
Something to ponder, rear LSD sorting understeer.
Aug 31, 2019, 04:28 PM
#9
Evolved Member
another option is Ralliart front plate diff... that can be run as 1 way or 1.5 way with choice of preload. bit expensive though as it comes with different carrier housing and output shaft.. Can be found used in Europe as it is standard equipment on gr N rallycars..
Aug 31, 2019, 11:07 PM
#10
At this point, I'm happy with my Wavetrac and have no complaints, but if I were ever move to a clutch type front diff I think Cusco holds the best record and has the most published info as well. I have a friend who just recently switched to an ATS 1 way from the stock LSD so once the season is over I'll ask him about any differences he's noticed.
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alpinaturbo (Sep 2, 2019)
Sep 2, 2019, 09:53 AM
#13
Wavetrac feels "like its not there", I have Wavetrac and "feel nothing".
I guess same as Torsen OEM RS.
I wondered if Shep installed it at first. Mind you, at the time of install the car was stock otherwise, and had plenty of traction-
so traction was not challenged.
I had Wavetrac installed in expectation/hope that I will be able to achieve the mythical "FWD pull" through corners, (out of corner) that I felt in Rally Fiat 128.
But nothing changed really, and later as power grew, I never had tugging or traction loss on front. Always smooth.
AYC on the other hand magically rotates rear, and that is very pleasant and pronounced.
When the car was on OEM suspension and on old original tires, and initially I wasn't expecting the rear to move, it was un-nerving - AYC felt sudden. Old tires and inexperience probably to blame.
With better tires and knowing AYC can/will work, the rear rotating predictably became confidence inspiring.
I guess same as Torsen OEM RS.
I wondered if Shep installed it at first. Mind you, at the time of install the car was stock otherwise, and had plenty of traction-
so traction was not challenged.
I had Wavetrac installed in expectation/hope that I will be able to achieve the mythical "FWD pull" through corners, (out of corner) that I felt in Rally Fiat 128.
But nothing changed really, and later as power grew, I never had tugging or traction loss on front. Always smooth.
AYC on the other hand magically rotates rear, and that is very pleasant and pronounced.
When the car was on OEM suspension and on old original tires, and initially I wasn't expecting the rear to move, it was un-nerving - AYC felt sudden. Old tires and inexperience probably to blame.
With better tires and knowing AYC can/will work, the rear rotating predictably became confidence inspiring.
Sep 25, 2019, 08:50 AM
#14
Well I talked to my friend with the ATS 1.5 way after he's done a few track days with it. He said it transformed the way the car turned in vs the factory helical LSD. TRE set the diff up, other than that I have no specifics on it.
I'd also like to note that he just won Speed Ring with this car in the Street Mod class and his lap times were breathing down the necks of many cars in higher classes that had more power, tire and aero.
I'd also like to note that he just won Speed Ring with this car in the Street Mod class and his lap times were breathing down the necks of many cars in higher classes that had more power, tire and aero.