LSD in summer and open diff in winter?

[AMMO]

Wondering if anybody has an opinion.

 

I fitted a Titan LSD earlier in the year and almost immediately bought another open diff and put the diff with the LSD up for sale.

 

After almost nine years of driving the open diff the LSD felt alien to me. Didn't like it much at all. Luckily nobody bought it and I soon got used to it. It is great if you are going for it but I am now wondering if I really want to stick with the LSD in winter. I have feeling it may be a bit of a handful on wet, greasy or icy roads.

 

I could stick the open diff that I have for the winter months and put the LSD back next spring.

 

What do you think? Anyone have experience of driving in bad weather with both types of diff? Pros and cons?

 

Thanks

 

 

 

Ammo

Raceco.com

[Mickrick]

Hi Ammo I can't compare between the two, as I always had a LSD.

But over here, the roads are a hell of a lot more slippy than U.K., even when dry, and treacherous in the wet.

I had no problems with the LSD in the wet. In my opionion, it all comes down to not having a big right boot!

I always found the car very controlable. I wouldn't even consider a Seven with an open diff. not for one second. My car was never tracked.

[Willie.]

Ammo,

 

What is it you don't like about the LSD? Perhaps you just need to modify it to suit you better (The beauty of plate type diffs).

 

For what its worth, I much prefer the LSD for all weather driving, and the car is much more predictable. For example, with an open diff, when you are booting out of a wet corner, you're wondering if its going to spin one wheel, or will both go, you're tense waiting to see what happens. With an LSD, you know that its going to let both go, so you know what to expect, and you can feel it coming on.

 

Having run with both, there is no way I would go back to an open diff. The LSD makes the car behave so much more consistantly, so makes it much easier to drive.

 

If your car is boring straight on at tight corners, kicking the tail out under braking or letting one wheel spin then the two...it needs modified.

 

Just my 2p...'cause you asked for it.

 

Willie

[The Village Idiot]

I'm with Mickrick with this one, having owned both types of diff I would never get rid of the LSD. With the open diff you just sit there with the inside wheel spinning up wondering when you will exit the corner, with the LSD you can get going so much earlier, however on slippery surfaces you have to be carefull how much power you put into the car as you are not spinning that power away on the inside wheel anymore.

 

Dicks

[Matthew Willoughby]

I am not a techy person at all so I may be talking complete ruubbish but.....

 

I prefer an open diff in the wet. It won't be as quick because you will spin up the inside wheel. However, with just the inside wheel spinning at least the outside wheel is still gripping. With an LSD both wheels will spin up reducing the amount of grip you have much more suddenly.

 

My old live axle (open diff) car felt much more forgiving in the wet than my new de dion car with an LSD and I suspect that this is the reason.

[AMMO]

Mickrick

 

"it all comes down to not having a big right boot!"

 

Yes, you have to be careful in a light car with rear wheel drive in bad weather. I think of it as a big motorbike.

 

Opposite Lock

 

The LSD works perfectly. The car comes out of corners better in the dry. In the wet the verdict is still out as I have only driven it in damp conditions a couple of times. Not driven it in heavy rain yet.

 

I've had the car almost nine years and I have not crashed it yet. Don't want to start now. So I suppose the question is which diff is safer / more user friendly / more forgiving to cack-handedness in the wet?

 

Richard

 

"however on slippery surfaces you have to be carefull how much power you put into the car as you are not spinning that power away on the inside wheel anymore."

 

Exactly, you are not spinning the power away, you are using the power to possibly initiate a slide. When you spin a wheel you just don't go anywhere. When both wheels are spinning and lose traction going around a bend (a straight line should be less of a problem) you could end up going sideways into something.

 

I suppose I need to suck it and see how I get on in the wet. Now that I have done a few miles on the LSD I am very tempted to put the standard spare diff in to see how different it feels.

 

Thanks for your responses so far.

 

Ammo

Raceco.com

[AMMO]

Thanks Matthew.

 

This is the sort of comparison I was looking for. A couple of people I have spoken to have said the open diff is more forgiving in the wet.

 

Ammo

Raceco.com

[Willie.]

Ammo,

 

Exactly, you are not spinning the power away, you are using the power to possibly initiate a slide.

 

Any what's wrong with that? 😬 Seriously though, what's the point in producing power, then fitting a diff with the intention of spinning power away?

 

In my opinion, its depends on what you want to do with the car. Do you just want to pootle about, or are you wanting to drive it on? If pootling about, then you only need an open diff, as if the wheels spin, you'll lift off and re-apply the power.

 

If you're wanting to drive the car spiritedly, I don't think it really matters what the weather conditions are. Why do people fit LSDs (Apart from donuts in McDonalds carparks)? Its to get better traction and more progressive handling (Its much easier to control a slide with an LSD than without). An LSD will give you this both in the dry, and the wet.

 

If you're for driving the car on a bit, then you are going to get wheelspin. I guess "Forgiving" means that, theoretically, only one wheel will spin and you'll be fine. But in practice this isn't always the case. Sometime you'll be mid corner, put the power on and both will go. Then you're sliding, wishing you had an LSD so you could control it better.

 

I drove my car all weathers with and without an LSD. Damp, torrential or snow, I prefer the LSD. It just always acts the same way at the limit of traction...but you also have a much higher limit of traction (For spin). When you pull out to pass someone in the rain, the offside wheel doesn't spin on the white line anymore. When you nail it out of a side road to get into a gap in the traffic, you don't sit there with one wheel spinning, you go.

 

With an LSD, you soon realise how much power/revs it takes to break the rear end away, so you can pull away fast without going broadside...much faster than you could with an open diff.

 

Anyway, I'll shut up now. My LSD is the single best upgrade I ever did to the car, and I absolutely love it. I'd hate the car without it. Get used to it and you'll be safer in wet or dry.

 

Willie

[Mr Locust]

Ammo,

 

the open diff is more forgiving in the wet

 

That is pretty much it really. If road use is your thing the open diff is less likely to spit you in the hedge provided you are sensible. Under many conditions it dumps the torque by spinning one wheel but more importantly, one wheel is still turning at road speed and giving grip which makes it more progressive to breaking away.

 

Once you break traction with the LSD it is both wheels breaking grip. You will have more traction up to the limit then it is a case of back off or throttle control and opposite lock all the way.

 

Tyre wear is more even though

 

Ian

 

Green and Silver Roadsport 😬

[Andy Honnor]

I went from open diff to Titan LSD last year. I agree that it felt different and that in the wet the rear brakes away with minimal invitation. However, having got used to it I would not change back. The LSD makes the car feel much more connected to the throttle; i.e more throttle = more slide and less throttle means more grip. I haven't ever experienced a sudden break in traction that is often described with LSDs; having said that, I don't think a Caterham with any diff would do that unless seriously provoked.

 

I went to the brilliant Dunsfold handling day and had a great play on the donut area to learn the limits of my LSD.

 

Persevere with the LSD and control the car with the right boot.

 

[millsn]

Hi ammo,

Winter diff? I'd never thought of that but it seems a good idea to me. One day they'll be electronic and you'll dial the wet setting in I suspect!

 

I don't much like mine in the wet, with dry weather tyres and the LSD it's a bit much, constantly feeling on edge. I suspect it's the combination that causes the problem but you could really be a dunce with the throttle before the LSD. Might be worth considering the tyres you run before swapping your diff though.

[Mickrick]

dumps the torque by spinning one wheel but more importantly, one wheel is still turning at road speed and giving grip

Er... wrong!

Once you lose traction with one wheel, you'll lose drive to the other, with an open dif.

[Drumster]

Ammo,

 

Like you I had an open diff for many years (10 to be precise) in my 140 bhp x/flow and felt the need for an LSD (got a ZF from RRT) this year as I was sprinting/hill climbing. It was fitted just 2 weeks before we set off on our 2,000 mile Swiss Trip and I adapted to it and felt strangely at home with it immediately.It certainly seemed beneficial when 'playing' with the hairpins on the passes, albeit 2-up with a fair amount of luggage. At times the weather was appalling, but I never felt uneasy with it like I have with the open diff.

 

My only concern is that with 'spirited' driving I'm noticing more understeer as It pushes on more in the corners.

 

Chris Alston

C7CAT 1800 Supersprint

R248 ....and then I jumped in

[Dickie Normuss]

I've got an LSD in mine which for a while was my only car which included 2 winters. The daily commute is 100 miles so I experienced everything from light rain to heavy snow and everything in between. Not once did I ever feel I was in danger of being bitten but I think it was down to the way I drive. I've always been a cautious driver, more so in poor conditions and worked conciously to go easy. In summary you'll be fine

 

VX HPC - Loud and proud here

Adding power makes you faster on the straights. Subtracting weight makes you faster everywhere

[Mr Locust]

Er... wrong!

 

That always sets the tone of any response to a thread for me. BADLY. Like when a three year old says why for the fifth time...................

 

Once you lose traction with one wheel, you'll lose drive to the other, with an open dif.

 

Correct. But what you have failed to realise is that by unloading the traction forces from the (not spinning) tyre you give it more chance of maintaining lateral grip. Which for most road conditions is good. The lateral grip will generally tend to resist the back of the car spinning around and overtaking the front. (Google traction or friction circles).

 

On that basis if you are inexperienced, caught out by road conditions or just half asleep, unexpectedly spinning an unladen wheel but not the whole car on a corner is generally a safer in a road driving context. That doesn't mean it isn't frustrating to spin a wheel when you want to (think you can) go faster.

 

But that assumes you go everywhere on the limit. Thankfully on the road most people don't.

 

As long as you drive to the conditions the LSD will not give a problem but it can step sideways more easily at the limit in poor conditions, especially if your throttle control is not smooth. The traction advantages from a LSD will become more with increasing engine power/torque. I can't see it justifying a seasonal diff change though.

 

Just for information. My car has a ZF LSD and I have had cars without. I don't usually drive this car in bad weather beyond rain and cold but have used the others in rain, hail, ice and snow.

 

Going back to Ammo's original posting he asked if anyone had an opinion based on experiences. Opinions are like 🙆🏻: Everybody has one

 

Ian

 

Green and Silver Roadsport 😬

[Mickrick]

That's the trouble with these bloody forums isn't it. You can read it any way, and imagine a "Tone". You didn't mention "lateral" grip. I assumed we where talking traction. But I get your point.

I'll just feck off now shall I.

[AMMO]

Thanks for the replies.

 

"If pootling about, then you only need an open diff, as if the wheels spin, you'll lift off and re-apply the power."

 

Keep in mind that I'm trying to commute from A to B and get back in one piece, not trying to set a record lap at the 'Ring. Wasting a fraction of a second is less important to me than avoiding going sideways, driver's side first, into the oncoming truck when I lose it on a left hander.

 

There is a telegraph pole on a bend on my way to work that has a bunch of flowers tied to it that has a sobering effect on me. It makes me speculate what would happen if I lost it big time.

 

I suppose my driving may be a bit more spirtited than your average commuter. If I was pootling I wouldn't have a problem with losing traction.

 

"Winter diff? I'd never thought of that but it seems a good idea to me. One day they'll be electronic and you'll dial the wet setting in I suspect!"

 

I was discussing this with someone. It would be nice to be able to flick a switch and go from one to another.

 

"But what you have failed to realise is that by unloading the traction forces from the (not spinning) tyre you give it more chance of maintaining lateral grip."

 

Quite keen on lateral grip!

 

I think what will actually happen is that I will leave the LSD in. It is great in the dry although in certain conditions I have experienced some under-steer. I should really try it in bad conditions rather than speculate. If I should scare myself witless with it fitted I always have the open diff to stick in and see if that improves matters.

 

Thanks again for your comments and opinions.

 

Ammo

Raceco.com

[Jason Plato]

I sounds to me - but I may be wrong that throttle sensitivity and what to do in the event of a slide is a problem for you Ammo?. Why not investigate fitting a traction control system ? and, or get some training in skid/ slide control ?. I will improve you confidence and safety. Or buy a £300 banger for the wet days ?

 

dave

 

 

 

here is my Duratec R .... C7 TOP

Taffia joint AO with Al

 

[dannylt]

He's just got too much power for an old man .

 

Ammo - you need a "wet map" like we did for mine years ago - just takes the edge off on initial throttle opening.

 

DJ - I'm not sure his banger is even worth £300...

 

danny

[AMMO]

Dave

 

Was thinking of traction control. The Emerald ECU is able to support it.

 

I was also thinking (for the past 5 years!) that I should do something about a more progressive throttle linkage as the initial movement on the throttle is a bit abrupt. I am used to it but the initial throttle application has to be very delicate. This probably isn't helping.

 

I have an engine at work with a set of bodies fitted and some different quadrants and ideas to try. Need to make my own linkage kit for the throttle bodies I have had made by Jenvey. I have had some extra bosses cast on the bodies as potential mounting points. This is a good excuse to sort it out once and for all. I want something that has a lot of movement initially that gets progressively quicker as throttle goes to fully open.

 

Did some skid pan training with the local police at Martlesham headquarters a few years ago. Learnt quite a bit. Could do with going again but unfortunately they have stopped doing the courses for health and safety! and insurance reasons. Just in case somebody gets hurt on their skid pan and sues I suppose.

 

I had a great little Citroen £150 banger bought in 2003 but I gave it to my son. Best car I have ever owned. Flew through the MOT six years running. Need to get another tin top but want to persevere with the Caterham as it is not getting enough use. If I get another tin top I think the Caterham will end up parked in the garage all the time.

 

Danny

 

I really am starting to feel my age. I'm getting less interested in driving fast all the time but even more interested in developing engines so others can go fast.

 

It was always the case with the bike racing. I was building fast engines that were too powerful for me to control but a joy to watch when properly used in the hands of others. Having mixed with quite a few racers I know that I am not in, or ever will be in, their league, so no point even trying.

 

Still like to give it a bit of squirt now and again though. Some of my passengers think that I drive fast, but I know what really fast is and I can't do it.

 

Should hopefully be going to Emerald soon for some mapping ona 2.2 Duratec. I was thinking of getting a lean map for my car for touring as currently the engine is a bit juicy. At the same time I can get a wet map done.

 

Good idea! Didn't think of that.

 

 

 

Ammo

Raceco.com

[metal mickey]

Danny, you have it summed up 😬

[Mr Locust]

initial movement on the throttle is a bit abrupt

 

The first mod I made to my Jenveys was a home brewed variable rate throttle lever. The standard, bare lever looked like it would give pretty poor fine control at small openings.

 

My map also has more %tps resolution at low openings i.e. the load intervals are not equally spaced from 0-100.

 

Ian

 

Green and Silver Roadsport 😬

[Damdy-Cash]

The first mod I made to my Jenveys was a home brewed variable rate throttle lever. The standard, bare lever looked like it would give pretty poor fine control at small openings.

 

could you show some pics or give some more details how that was done? I struggle with the same.

 

cheers Volker

 

German Sevener in Scotland

[Golf Juliet Tango]

Still like to give it a bit of squirt now and again though. Some of my passengers think that I drive fast, but I know what really fast is and I can't do it.

A very wise comment Ammo. I might suggest that you know what fast is and know what "too fast for a particular road" is too?

 

_{Democratic dissent is not disloyalty, it is a positive civic duty.}

[Blackbirdman]

Stick with the one you've got Ammo....

 

 

(Then he won't be coming round to my place to change it every six months )

 

Matt

 

 

 

Life begins at 10,000