A1337STI Alex Rademacher Mega Moderator Location: Reno,nv Join Date: 09/10/2007 Age: Midlife Crisis Posts: 686 Rally Car: 93 GC with an 01 RS swap! |
So I want to setup my car to be the most fun (that an AWD car can be)
which is probably to make it behave more like a RWD car . what changes would best accomplish that ? right now my car is Torsen - 4kg Center viscous - rear viscous . I want it to behave a lot more like my STI (torsen - computerized center - Clutch) not planning on buying a fancy center . Lets say we are in a typical R3 In my STI on the dirt if you just turn in more and go WOT the back steps out and you drift (weeeeee) in my RS 2.5 on the dirt if you Only turn in more and go WOT the car drives through the corner, maybe after 1-2 seconds the rear "locks up" enough it starts to step out a little, but that's usually after the apex. its not very helpful and its not Nearly as much fun. should i just throw a rear clutch LSD (maybe up the break away torque) and call it a day? would a spool be a better idea ? would a spool in the back be a horrible idea for something i'm not thinking about ? thanks |
aj_johnson A.J. Johnson Ultra Moderator Location: Pendleton OR Join Date: 01/07/2011 Age: Settling Down Posts: 1,381 Rally Car: 88 Audi 80 |
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Pete Pete Remner Infallible Moderator Location: Cleveland, Ohio Join Date: 01/11/2006 Age: Midlife Crisis Posts: 2,022 |
Locking the center and rear (so two spools) makes my AWD car drive like a rear drive car, but not in a good way.
I don't see why you'd want to make an AWD car drive like a rear drive car. Make it drive like an AWD car, otherwise why bother? IIRC, the Delta Integrale had some sort of center diff that biased heavily towards the front, theory being the car is nose heavy so the torque should be nose biased. Seemed to work just fine for them. Pete Remner Cleveland, Ohio 1984 RX-7 (rallycross thing) 1978 Silence is golden, but duct tape is silver. Edited 1 time(s). Last edit at 07/28/2014 05:12PM by Pete. |
Sean Edwards Junior Moderator Location: Arlington WA Join Date: 11/17/2010 Posts: 82 Rally Car: Celica |
I'm dealing with the same situation but with an even less desirable factory setup.
I have open front & rear diff with a viscous center, and it is very unpredictable on gravel and wet tarmac. Almost exactly the same driving situation as the OP described. I'm interested in what others have done. |
NoCoast Grant Hughes Senior Moderator Location: Whitefish, MT Join Date: 01/11/2006 Age: Midlife Crisis Posts: 6,818 Rally Car: BMW |
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A1337STI Alex Rademacher Mega Moderator Location: Reno,nv Join Date: 09/10/2007 Age: Midlife Crisis Posts: 686 Rally Car: 93 GC with an 01 RS swap! |
I found a guy in japan that will ship a 12kg or the 20kg for about 750$ us shipped ..
strangely i never really thought i should touch that diff. hmmm ... so if the center is a bit more "locked" you are always getting more power to the rear so any positive handling changes on that diff, become more pronounced. would that be part of the why ? with a torsen in the front as long as your entry speed is reasonable you don't get throttle on under steer. the very very little I've driven a car with a plated (clutch) Front diff i noticed that some really bad understeer was possible at a reasonable speed if you didn't lift a bit before your steering input. do you feel the benefits of a plated front out weight a torsen (front axle only) I have definitely noticed that with the Torsen if your left tires go over some looser gravel and the right side is hard packed you get sort of a "push off" from the right side . when my car was FWD the effect was much more notable. i found that my car was Much easier to drift and modulate the line when the front diff was open, versus the Torsen. i was much faster with the torsen, but i had to drive a more tidy style which in and of itself isn't as much fun (to me) with the AWD setup and directional tires i don't notice the torsen jacking with my drift angle . it never requires a rebuild , and does not require friction modifier or frequent fluid changes either. good info btw! |
aj_johnson A.J. Johnson Ultra Moderator Location: Pendleton OR Join Date: 01/07/2011 Age: Settling Down Posts: 1,381 Rally Car: 88 Audi 80 |
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NoCoast Grant Hughes Senior Moderator Location: Whitefish, MT Join Date: 01/11/2006 Age: Midlife Crisis Posts: 6,818 Rally Car: BMW |
Here's some previous discussion on this topic.
http://www.rallyanarchy.com/phorum/read.php?5,34956,35059#msg-35059 Grant Hughes |
Doivi Clarkinen Banned Godlike Moderator Location: the end of the universe Join Date: 02/12/2006 Age: Possibly Wise Posts: 1,432 Rally Car: 1980 Opel Ascona B |
Center diff first, weld it if you have to. Then rear diff. Front diff last, and really it's optional. A limited slip front diff is going to give you initial understeer. If you don't address the center diff first you're never going to have anything that behaves properly.
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HiTempguy Banned Junior Moderator Location: Red Deer, Alberta Join Date: 09/13/2011 Posts: 717 Rally Car: 2002 Subaru WRX STi |
If you were going through all of this effort, I'd look at sourcing a DCCD 5 speed close ratio box. The price won't be much more than the 20kg center and the close ratios will really help you out.
I know that this doesn't answer the OP's question, but knowing that he is doing stage rally, that means he is racing. I'm recommending the best course to take for going faster. Also, the 20kg will require a significant change in driving style. You REALLY have to be aggressive with the car or you will hate your life. |
A1337STI Alex Rademacher Mega Moderator Location: Reno,nv Join Date: 09/10/2007 Age: Midlife Crisis Posts: 686 Rally Car: 93 GC with an 01 RS swap! |
Read that entire other thread.
I think the reason i'm attacking from the wrong end is that my first 12 or so rallies my car was FWD. (4 of which i did with a Torsen front LSD) the Torsen (OBX For $370) was really amazing in that it did not introduce any under-steer what so ever. so center, center, center, center is what i'm reading. If i was OPen - Stiff center - Rear clutch . am i going to get that "heavy" drive train feeling that burke's car has? cause i don't like that heavy , "hey you better THROW your car into every corner, every time" kind of feeling. i like options . like the option to drive through some corners while keeping it very tidy (Ruts, Rocks, Extra Rough, hell maybe i see 2 rally guys at a triangle with an OK sign, the same 2 guys i saw last running of the stage and i can get by their car at speed, but i really don't want to spray their windshield with rocks ) and of course the option that yes i can throw it very sideways and steer around with the gas peddle. So it sounds like i should Keep my best Clutch pack rear LSD. sell off a few of my extra LSD units and get an upgraded center? and do the front last (or get that cheapie obx that's been working for me) I did break my front obx @ idaho in 2012, by sliding into a boulder with my front left tire . |
A1337STI Alex Rademacher Mega Moderator Location: Reno,nv Join Date: 09/10/2007 Age: Midlife Crisis Posts: 686 Rally Car: 93 GC with an 01 RS swap! |
Hey Jvab do you recall saying you know of 1 guy that can re-set a viscous ? happen to have his number.
think you said it was around 150 pounds or euros (maybe it was 250) i want to give him a call and figure out options [this would be for my center diff] was it these guys ? http://www.baramotorsports.com/viscous_couplings.htm Edited 1 time(s). Last edit at 07/29/2014 11:43AM by A1337STI. |
john vanlandingham John Vanlandingham Mod Moderator Location: Ford Asylum, Sleezattle, WA Join Date: 12/20/2005 Age: Fossilized Posts: 14,152 Rally Car: Saab 96 V4 |
Yeah, it's Bara. My memory says we had a talk about fuckin email. Like me most of those Pommie bastids hate email so yeah call him... I think its +8 hours. John Vanlandingham Sleezattle, WA, USA Vive le Prole-le-ralliat www.rallyrace.net/jvab CALL +1 206 431-9696 Remember! Pacific Standard Time is 3 hours behind Eastern Standard Time. Edited 1 time(s). Last edit at 07/29/2014 11:56AM by john vanlandingham. |
A1337STI Alex Rademacher Mega Moderator Location: Reno,nv Join Date: 09/10/2007 Age: Midlife Crisis Posts: 686 Rally Car: 93 GC with an 01 RS swap! |
that will save me a few weeks of wondering why my email goes unanswered , thanks
funny that ralli-spec has anti marketing on their center diff page, but if you read carefuly they do agree with rally anarchy http://www.rallispec.com/dif_gls_rst1215_t.html
$1200 .. ouch guess the viscous rebuild folks might be a cheaper option, even after shipping and converting my US GDP backed paper for UKs GDP backed paper |
john vanlandingham John Vanlandingham Mod Moderator Location: Ford Asylum, Sleezattle, WA Join Date: 12/20/2005 Age: Fossilized Posts: 14,152 Rally Car: Saab 96 V4 |
Well I have a "pumped up" center diff on my Frod Crossways thing and a ordinary VC rear.. Car works real good but Ford's center epicyclic power split sends 2/3s powerz rear, 1/3 powerz front.. It is loadsa fun... Like RWD+ John Vanlandingham Sleezattle, WA, USA Vive le Prole-le-ralliat www.rallyrace.net/jvab CALL +1 206 431-9696 Remember! Pacific Standard Time is 3 hours behind Eastern Standard Time. |