sevaun
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| posted on 26/1/11 at 08:36 AM |
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Spooling a diff
I'm converting my roadgoing bookbuilt chassis to use purely for autotesting. One of the tweeks I'm considering is welding/
locking/spooling the diff to get more traction without the expense of a LSD. Does anyone have any experience of driving a car with a locked diff,
particularly in autotesting or similar?
Richard
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carpmart
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| posted on 26/1/11 at 08:52 AM |
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My race car has no differential so is a locked diff. It's an enhanced driving style you will have to learn in effect you need to induce
oversteer and then control it to get round corners. It will feel like you have loads of understeer but that is because the back really pushes through
the front of the car. (not sure that makes sense as it is poorly articulated!  ) The set-up with no diff is very predictable so inspires confidence
to get the back end out.
HTH?
You only live once - make the most of it!
Radical Clubsport, Kwaker motor
'94 MX5 MK1, 1.8
F10 M5 - 600bhp Daily Hack
Range Rover Sport - Wife's Car
Mercedes A class - Son's Car
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sevaun
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| posted on 26/1/11 at 09:58 AM |
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quote:
Originally posted by carpmart
My race car has no differential so is a locked diff. It's an enhanced driving style you will have to learn in effect you need to induce
oversteer and then control it to get round corners. It will feel like you have loads of understeer but that is because the back really pushes through
the front of the car. (not sure that makes sense as it is poorly articulated! ) The set-up with no diff is very predictable so inspires confidence
to get the back end out.
HTH?
mmmm.. understeer might be a problem in tight situations on an autotest course, but like you say once the backs out it should be more controllable.
Thanks
Richard
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carpmart
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| posted on 26/1/11 at 10:53 AM |
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I don't think locking the diff actually reduce front grip, it just feels like it does!
You only live once - make the most of it!
Radical Clubsport, Kwaker motor
'94 MX5 MK1, 1.8
F10 M5 - 600bhp Daily Hack
Range Rover Sport - Wife's Car
Mercedes A class - Son's Car
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Nash
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| posted on 26/1/11 at 11:09 AM |
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I used to race an F2 BRISA Stockcar a gazzillion years ago with a welded diff. I wouldn't think it would be useful in Autotesting as it is less
agile / nimble then a stock diff.
Is it something common they do in Autotesting or are you looking at it as an inovation?
.............. Neil
It's What You Do Next That Counts.
Build It, Buy It, Drive It:
Southern Kit Car Club
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sevaun
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| posted on 26/1/11 at 12:46 PM |
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quote:
Originally posted by Nash
Is it something common they do in Autotesting or are you looking at it as an inovation?
.............. Neil
Inovation really. probably won't make a great deal of difference on small tight layouts, but on long fast sections it could be useful for
getting traction down after a manouvre. Also we'll be doing some grass autotesting where a locked or lsd would be very useful.
Richard
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Doctor Derek Doctors
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| posted on 26/1/11 at 12:55 PM |
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They're fine in the dry but absolutely useless in the wet and downright dangerous on a wet road.
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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Liam
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| posted on 26/1/11 at 07:10 PM |
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I would have thought in autotest more time is to be saved in the twisty bits (the whole course?) than 'long fast sections' (do they
exist?) where you wouldn't want to be giving yourself extra understeer. But then if you have the torque to wheel-spin on demand, maybe a
welded diff's a good thing?
Best answer is to just ask this guy what he's using and go for that...
http://www.youtube.com/watch?v=3Rhz19ZrpZg
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Neville Jones
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| posted on 27/1/11 at 11:07 AM |
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Autotesting needs tight turning and agility. The exact opposite of what a 'spooled' or locked diff will give you. You need to be able to
turn in easily and quickly, and get drive out of the turns. The locked diff WILL give you attrocious turn in push, and violent power reactions,
especially on the tarmac most of these events are held on.
Innovative? No, not really. It's been done and found severely wanting.
What you need is a very good lsd, set up to your style. Viscous don't do the job for this either.
Cheers,
Nev.
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sevaun
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| posted on 27/1/11 at 02:44 PM |
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Sound Advice
That sounds very sensible advice and from someone who's been there.
Come to think of it that also applies to my other project at the moment. I've stripped my bike engined single seat hillclimber for a winter
overhaul. I discovered it runs an open (fiesta)diff, whereas I was led to believe it was LSD. Your comments about viscous LSDs answers a thought I had
about fitting an Escort RS turbo viscous LSD. The car already tends to understeer and from what you say a viscous diff would probably make the
situation even worse.
Thanks Nev
Richard
[Edited on 27/1/11 by sevaun]
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Uphill Racer
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| posted on 27/1/11 at 10:31 PM |
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This is worth looking at.
http://www.phantomgrip.com/
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Doctor Derek Doctors
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| posted on 31/1/11 at 01:01 PM |
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quote:
Originally posted by Uphill Racer
This is worth looking at.
http://www.phantomgrip.com/
All sounds a bit like snake oil to me. No pics of the internals or any real engineering info.
Not having a list of fitments or prices doesn't really help either. A shame as it coul;d be a decent bit of kit.
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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Kriss
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| posted on 31/1/11 at 01:37 PM |
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I have had a play with a pinto Indy with welded diff and it was terrible.
So much understeer (certainly what it felt like from the rear)
I can kick the back end out in my LSD indy and do nut, figure of eight do nut etc, but not a chance with the welded diff, just felt totally
unconnected and horrible.
Would think in the wet or grass would be even worse.
get a 3.62 sierra lsd for less than £300?
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Richard Quinn
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| posted on 31/1/11 at 01:55 PM |
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quote:
Originally posted by Doctor Derek Doctors
quote:
Originally posted by Uphill Racer
This is worth looking at.
http://www.phantomgrip.com/
All sounds a bit like snake oil to me. No pics of the internals or any real engineering info.
Not having a list of fitments or prices doesn't really help either. A shame as it coul;d be a decent bit of kit.
There are a few clues on the "installation instructions" page HERE I
think I'll keep my wallet in my pocket for now.
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daviep
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| posted on 31/1/11 at 02:04 PM |
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quote:
Originally posted by Uphill Racer
This is worth looking at.
http://www.phantomgrip.com/
Looks like a housing with some strong springs to exert pressure between the planet gears, not going to be very healthy for the thrust washers behind
the planet gears.
“A truly great library contains something in it to offend everyone.”
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loggyboy
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| posted on 31/1/11 at 02:09 PM |
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To make use of a welded diff you;d have to be pretty much constantly sideways, opposite lock to opposite lock. You might get that on an Autosolo, but
defo not at an Autotest.
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blakep82
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| posted on 31/1/11 at 02:59 PM |
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terrible idea IMO. ok for drifiting and drag racing i guess, but anything involving corners (without both wheels smoking) it will be pretty hopeless
________________________
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don't write OT on a new thread title, you're creating the topic, everything you write is very much ON topic!
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Uphill Racer
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| posted on 3/2/11 at 12:35 AM |
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quote:
Originally posted by daviep
quote:
Originally posted by Uphill Racer
This is worth looking at.
http://www.phantomgrip.com/
Looks like a housing with some strong springs to exert pressure between the planet gears, not going to be very healthy for the thrust washers behind
the planet gears.
The springs need only be 'strong' enough to try to provide a rotational force against the spider gears. I love its simplicity and the
testimonials look good.
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blakep82
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| posted on 3/2/11 at 01:28 AM |
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quote:
Originally posted by Uphill Racer
quote:
Originally posted by daviep
quote:
Originally posted by Uphill Racer
This is worth looking at.
http://www.phantomgrip.com/
Looks like a housing with some strong springs to exert pressure between the planet gears, not going to be very healthy for the thrust washers behind
the planet gears.
The springs need only be 'strong' enough to try to provide a rotational force against the spider gears. I love its simplicity and the
testimonials look good.
i'm sure if i wanted to sell people something that doesn't work, i could write a few good testimonials 
________________________
IVA manual link http://www.businesslink.gov.uk/bdotg/action/detail?type=RESOURCES&itemId=1081997083
don't write OT on a new thread title, you're creating the topic, everything you write is very much ON topic!
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Uphill Racer
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| posted on 3/2/11 at 01:41 AM |
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quote:
Originally posted by blakep82
quote:
Originally posted by Uphill Racer
quote:
Originally posted by daviep
quote:
Originally posted by Uphill Racer
This is worth looking at.
http://www.phantomgrip.com/
Looks like a housing with some strong springs to exert pressure between the planet gears, not going to be very healthy for the thrust washers behind
the planet gears.
The springs need only be 'strong' enough to try to provide a rotational force against the spider gears. I love its simplicity and the
testimonials look good.
i'm sure if i wanted to sell people something that doesn't work, i could write a few good testimonials
Well I thought the concept was good, can you explain to me why it wouldn't work?
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blakep82
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| posted on 3/2/11 at 02:15 AM |
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well, looking at it, it appears to be a small box containing springs, which pushes against the side gears in an open diff giving some resistance.
have a look at this, its an exploded diagram of a plate type LSD
_gif.jpg)
it also features a plate inside with springs acting on the side gears, but the side gears are forced onto clutch plates which locks the gear against
the diff case.
without those clutch plates, what does it lock the gears onto? onto a thrust washer basically, or an oiled up shim. and if it was that easy, why do
tran-x, quaife and others bother with the plates?
i produced a small magnet which is glued on the side of an axle, pulling the gears out (rather than pushing them like on normal LSD set ups)
here's some testimonials
dave, oxford
i was sceptical on how a system half the price of normal LSDs could work, but i stuck the magnets to the side of sierra diff as shown in the
instructions. all i can say is WOW my cars handling has been completely transformed! on hard acceleration, my car used to just spin the right hand
wheel, but now i can drift my car round roundabouts! its amazing.
keving, doncaster
i fitted this to my skyline in minutes. i couldn't beleive how easy the instructions were to follow. the device was fitted in minutes, without
all the expensive set up normally needed for the usual LSDs. best £200 i've ever spent!
you get the idea... testimonials mean nothing really
________________________
IVA manual link http://www.businesslink.gov.uk/bdotg/action/detail?type=RESOURCES&itemId=1081997083
don't write OT on a new thread title, you're creating the topic, everything you write is very much ON topic!
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