FE-FC Holden Discussion Forum

Hi all,

I'm deciding whether to install an LSD or keep the FC a peg leg.

I haven't owned an LSD equipped car before, and I'm having conflicting views from people telling me why I should/shouldn't.

I'm looking for advice and experience as to why I should or shouldn't to make my decision clearer.

My car runs a hot 202, 5 speed, four wheel discs, running a Centura diff. I anticipate that I'll do some off-street drag racing and circuit racing/time trials once the car is complete.

Kind regards,

Ol_Girl_58 

LSD is a little tail happy on a greasy road  ;D ;D  but a lot of fun  ;D to get the power down and drive the car through a corner LSD for me ......FC427......

This is what I'm not looking forward to, Mark  :-\

The car will also have tramp rods, sway bars and road legal semi slick tyres (but probably won't make that much difference to the rear from coming undone). :-\

The car will predominantly be used for 'normal' road use.   

Put an LSD in it. It'll only go sideways if you tell it too  ;D

With the engine you've got I'd be looking for a 3.55 or if you drive longer distances a 3.36.

They ain't cheap these days though, maybe $600+ for a good one unless your lucky and stumble across something.

They typically wear the LSD cones which are not easy to get.

I know a guy in Sydney that has some parts still and last one I got rebuilt (3.08) cost $500.00 and included a good second hand crown wheel and pinion, bearings, and new LSD cones.

The 3.08 was fitted for my trip to Victoria last week and will be removed soon as it blunts the performance of my car too much. Spends too much time 'off the cam'.

I picked up an LSD disc brake rear out of a 170,000 kilometre ZH Fairlane a couple of years ago for $100 - it's all in good condition. I think the Centura has a 3.55 in it at the moment.

Hi Josh,

If you are going to do any drag / track work with the car keep a single spinner in it.

I have a 3.89 LSD in HIS and it is too tall
I have a 3.08 single in Hers with a 5 speed and it is a great higway cruiser
I have a 3.55 single in the number 53 and it sems ideal for the track.


regards

Weddo

So when it unloads the inside wheel what happens??????

Proper track cars use locked diffs for a reason. An LSD is a good road/track compromise.

A 3.89 will be too short, not too tall.

An option to buying a second hand LSD is this, around $400-500 when I last priced one.
http://www.4wdsystems.com.au/index.php?id=29

Im from tassie and have driven both. When you have a powerful engine is a light car, say going up hill on a slightly greasy or damp road, the thing will "snap out" sideways quite quickly with LSD, but on the dry doing a hill climb you will get way better traction, but if your a smooth driver, the latter shouldnt happen too much. It all depends on your driving style, if u reef it into a corner, you loose speed and the wheel on a single drive won't bite due to the weight transfer.

All LSD's are not the same, some have more slip.

LSD is good on dirt, but u have same thing happen when cornering, because both wheels break into wheelspin on dirt, u loose some ability of control. I think you would get used to both though.

When we just had our FG Falcon, if u turned off traction control it was quite dangerous in the wet (we are in bush)  if you put boot in, it whipped around quite quick and it had LSD but the new Commodores (we just got a new one) have similar setup IRS, LSD etc but they dont seem to wanna slide as much out of corners, but perhaps this is because the falcon engine has more torque, so its not a case of one shoe fits all.

If you know you have good throttle control - go for LSD
If you know u like to fang it and hang it out and are not a smooth driver- LSD will take a bit longer to get used to and may not be as safe in testing conditions - especially in Tassie :)

Hi Josh,

Mate if you get the LSD rebuilt, tell the guys doing it not to shim it up too tight. That way it will still be forgiving when driven normally & if you sink in the slipper on a corner or a wet road it will still go slieways ;D. remember that it is easier to hold a car in a slide with both the back wheels doing the same thing & not having one decide it will join the party when you least want it to.

Dean.

My XU1 has 260hp, weighs just over 1100kgs, and drives perfectly with a tightly shimmed LSD. It can definitely be hairy in the wet but is easily controlled.

The engine Josh has with a single spinner will just be impossible in the wet as he won't find traction.

From what I've been told, I can expect the car to 'bite' going around corners and get tail happy.

You're right, Craig re: the motor. It is slightly nuts, and although it was well behaved on most occassions, it could melt the rear tyres (well, one of them, at least) effortlessly.

It's going to be a handful with an LSD, huge cam and solid centre clutch, I think  :-\

my rodeo is very tight and with the big wheels and v6 it sometimes gets a bit hopping in the ass end on a high grip surface ha ha. Overall from what i can gether you would be better off with a LSD, just take it easy until you get used to it in slippery conditions. drifting is fun anyway, but ive seen my fair share of rallies in tasmania and she aint all that safe with cliffs and trees  :D

I think Dean is on the money though. A XU1 is a bit different to an FC too.

Very similar weight but higher centre of gravity and therefore more likely to lift an inside wheel and lose traction.

Josh, why don't you do what some guys do? They have a locked diff set aside for track work. Keep the LSD for the street and put your locked diff in when going to the track. Still street driveable but a pain when turning slowly. Makes more sense if you don't go very often.

When I broke an axle in my EH, (CIG locker), it was undriveable. It effectively became a single spinner but just spun the good wheel at will in the dry. I couldn't use any throttle at all.

How much life do you expect to get out of those tyres? If they are the tyres we use on the track I don't think they'd last much more than a couple of thousand kays on the street. Especially if you 'use' them.

Colin.

Hey Craig unless it has been strengthened an fc body would flop around too much and twist so much that lifting the wheel might be difficult ha ha  ;D Im just joking.

Its not something like an engine etc, just do it and if ya dont like it, take it out and sell it to me? I will definitely buy it off you and put in my second fc/fe i just got. u could go Volvo Dana, shortened commy or whatever u like. Its up to u at the end of the day but I bet if u dont do it you will be left wondering.

Josh, just had a re-read. Are you using a solid centre clutch? On the street? Even we don't use them on our race cars. Too savage on the drive line. We do have crash boxes and standard axles though. That's how I broke my axle. On the grid, holding 4000 rpm and dropped the clutch, snapped the left axle instantly. We have to slip the clutch on take-offs even with a sprung plate.

Colin.

Colin, yes, I'm using a solid centre clutch, on the advice of friend well seasoned in circuit racing who has a similar driveline set up in his LJ XU1 track car (which has good road manners). However, the more I think about it, the more I think that I should've purchased a sprung centre clutch.

Fcwithrb30, the addition of the chassis kit ensures my FC is quite rigid.

Thanks for the input so far, guys  :) :)

Josh

Hey Josh,

Any chance of exchanging the clutch, a mate of mine had a solid centre clutch in his Capri 351 equipped ;D, but it was a bitch of a thing to drive around in traffic.

Dean.

I had a full button clutch in my XU1 but impossible on the street and because I had to try to slip it flogged out the flywheel face in no time. Even worse the hotter it got.

Now fitted is a cushion button which is more manageable but still a little aggressive if you get caught in traffic.

Both clutches don't like to back the car up but have been hammered at the drag strip and track where they work well.

My next clutch is sitting on the shelf in the garage - an organic one and that's what I reckon you need to use. Just specify what you're going to use the car for to the clutch supplier and they'll give you something that is most suitable.

LSD's are cool, you can lay two black lines down instead of one.

Other than that you really don't notice it all when street driving.

Cheers

Ed

That ok I was sort of joking when I said about the flex as it has always astounded me how the original stock car seems to not have much in the way of ladders underneath etc, I found this pic in Unique cars that may interest you, most guys these days would have better handling FE's than the one racing here in QLD, thats why I was joking about the rear wheel not lifting if u didnt have a chassis kit or beefed up suspension  :D

(http://i1182.photobucket.com/albums/x448/fewithrb40/Email0022.jpg)