Not enough front wheel traction at hillclimb

J

JamesB

Guest
Hey all - just had my first go at collingrove hillclimb in south australia and did the R proud (or it did me proud - whatever) with a 37.28 best run. Beat several more experianced rex owners with same level off mods (coilovers, strutbrace, big balls) and ran only a couple seconds slower than some serious race prepped evo 6/7s!
Back on the topic, the top part of the track is v tight 1st & 2nd gear stuff with rough but nicely cambered corners but i was suffering huge front wheelspin (remember - no performance mods) out of the corners on new road compound Potenzas. I wasn't ploughing with understeer either! When doing the warm up burn out it felt like it took about 1.5 seconds for the back wheels to really get going (felt it break to the side). Unfortunately haven't done the gearbox, transfer and rear diff with new fluid (since compliance 6 mths ago) but have castrol syntrax ordered. What should i be putting in my middle diff to get the power down - something different. Also read in a mag (Zoom) that the luxury R (which Ive got) has rear LSD and viscous in middle and front. I thought it was LSD rear and middle and only an open front - can someone clarify this please. If the front is viscous the where do you put the fluid in. If you have any other tips to improve my times other than performance mods (will be making a rear strutbrace before the next round), I'd appreciate it. Cheers all. :D :D
 
gtiroz

gtiroz

Administrator
Staff member
hey james,
(is this james at heinrich? member of the oz club?)
well done beatin the scoobies mate :)

the gtiroz member SA boys (fil, andrew, brendan and glenn) all have experience at collingrove
and should be able to help you with queries about that track...
http://www.gtiroz.net/gallery/sa
(ask on the oz yahoo group)

and you say no performance mods?
you mean stock exhaust? stock boost?
unless those potenzas are really crap you should be gettin lotsa wheelspin...

deffo get strut braces front and rear, and all the whiteline uprated bushes are highly recommended (anti-lift kit is must)

you could also try this "cheaper than a real lsd" alternative:
http://www.gtiroz.net/gallery/phantomgrip

and yes zoom is wrong - it is an open diff at the front

[shalom]
 
Nad

Nad

Active Member
Shalom said:
you could also try this "cheaper than a real lsd" alternative:
http://www.gtiroz.net/gallery/phantomgrip

and yes zoom is wrong - it is an open diff at the front

[shalom]
Click to expand...
I take it u mean cheaper than front lsd alternative. Fronts will always spin anyway because its an open diff. Rears lag behind because of the centre diff is viscous and not mechanical. Its also sealed so u cant top it up and it may well be knackered depending on mileage its had thru it. Front being open obviously means u cant fill it with fluid but the back could always be pulled apart b4 u fill it up to check it.
 
J

JamesB

Guest
Yeah, bog stock performance except ARC top mount. The wheelspin is partially due to the adrenalin of my first hillclimb so getting my foot off the firewall is more mind over matter. Potenza G III's were brand new that day (195/50 15's) which I know will take a bit to get their full grip. Nad - I thought the centre diff was refered to as the transfer housing and was able to be drained and refilled. I remember asking on a post and someone saying it takes one litre and 1.5 in the rear (or vice versa). Shalom - I think Glenn spotted to me in Adelaide one day and had a good chat - said he's had his for 7 years and driven it round oz 3 times! Thats committed! Do you know anyone using this diff mod? How much improvement - How much $$$ over here?? BTW will be going in the next 2 winter cup rounds to try to catch my mate in his 2 door sti.
 
gtiroz

gtiroz

Administrator
Staff member
"the phantom grip lsd conversion kit"
$299US + you need the "spring tuning kit" for $30US
http://www.phantomgrip.com/

ivan is the only person i have heard that has installed one
(he was trying to get his rather large increase of power to the ground a bit better and it did help)
joe/carolyn (circuit racers) were looking into it but were having trouble contacting them
(all this was last year though)

maybe ask on the oz list if anyone has more recent info...
 
Nad

Nad

Active Member
JamesB said:
Nad - I thought the centre diff was refered to as the transfer housing and was able to be drained and refilled. I remember asking on a post and someone saying it takes one litre and 1.5 in the rear (or vice versa).

Do you know anyone using this diff mod? How much improvement - How much $$$ over here?? BTW will be going in the next 2 winter cup rounds to try to catch my mate in his 2 door sti.
Click to expand...
All the transfer box does is move the power thru 90degrees so it can go down the prop. Yes u can refill it but it is just transfer gears. The front diff runs thru the transfer case. The centre diff is in the gearbox and as it is a viscous one is sealed, although I would imagine it is different for other cars.

Not too sure if this link will work, if not just say.

Transfer case and front box view

Nad
 
J

JamesB

Guest
So i take it nobody really worries about upgrading their centre diff?? Do many people complain of such power transfer difficulties? You say the viscous diff is sealed - would have though it possible to open it and change the viscous gel? Ive tried taking off hard with back wheels on dirt/ front on bitty and vice versa but cant really work out if the back drive is up to scratch or not. It does drift in the wet quite well and it doesnt take off like a front wheel drive completely so I know its doing something. Is there anyway to work out how well my power is being split?? 4wd dyno perhaps...
 
Nad

Nad

Active Member
LeeSmith said:
all i get is


"You do not have access to this document"
Click to expand...
Will get it hosted somewhere and post it up.

I have a centre diff at home and the only way would be to cut it open. There are 2 parts to is, the spider gears which are visable and can be taken out and the viscous section which is sealed. Like I said, it may be worth replacing it with one with less mileage. Not sure how to test how much each wheel is putting out...

Nad
 
J

JamesB

Guest
My r's only done 95,000 kms - would have though that was too many clicks to stuff the centre diff (although car sat around for about 3 - 4 years before I got it on the road). Might give the local 4wd dyno guys a call and see what they say. Im in Oz so will chat to a few local R owners about their thoughts/experiances. Thanks for your input
 
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