Due to lack of knowledge, yet another diff question..

[DickieH]

Hi All
I’m researching the best/affordable spec for my future second hand 7 and some of you guys have been a massive help already. Im looking at a Roadsport 1.6K (budget £12-14k) and it won’t be doing track stuff. Trawling through the threads on diffs can anyone share their thoughts on the following diff queries please?:
1. Do I, or should I need an LSD for normal road fun?
2. What’s the approximate price premium for LSD on a used 7?
3. Are LSD’s generally the noisier type of unit?
4. How much more fun are they?
5. Would I regret not having one?
Thanks in advance
DickieH

[Yellow 7]

An LSD makes the car more focused and together when on the adhesion limit.
It actually enables better control and increased braking potential when entering a corner under heavy braking and of course traction is better coming out of the corners too. Plus standing starts are quicker and you can leave 11's or two black lines instead of one.
Under braking and cornering it controls potential lockups and i found I could stand on the brakes harder whilst the rear stayed under control. Without LSD it would be moving around more and like to break away. This was on circuit, same corners again and again and again... pushing pushing pushing.

This is not a massive issue if you are just pootling around the roads. However it does make a 7 much more predictable in the wet and less likely to fishtail - you can get nicer controllable power slides in both dry and wet.

If you need to use the cars max handling / braking in dry or wet - say to avoid a collision it will be working too.

The quietest type and ones that are fine for road and a bit of track are the AP Suretracks ones (not suitable for the biggest of powers as they can allow some spinning up still under a lot of torque) and perhaps the all gear type Quaife type. The ZF's seems to get a fair bit of press about noise and whining.
I had a AP Suretrack on my 2.0L VX 200 BHP slick shod racer and it was great. Quite easy as an after fit too really.

You can def have a Caterham and have fun without an LSD, but after a while I, and it seemed most of my 7 pals, gravitated towards them!

Edited by Yellow 7 on Thursday 31st May 14:22

[jackh707]

I'd be after a bigger engine at that price point if I were you.

[DCL]

IMHO,for all but the lowest powered cars, an LSD is desirable on a light car like the Caterham. If it is just for road use then a torque biased diff, as suggested above, will give you the best of both worlds. Plate diff will tend to make the steering heavy while manoeuvring.

The Quaife ATB is about £600 new (£1000 fitted?) so I wouldn't have thought it should add to the price significantly.

[HustleRussell]

jackh707 said:

I'd be after a bigger engine at that price point if I were you.

Are you new to Caterhams?

OP- In the real world and in my humble opinion, many Caterham drivers have an LSD without really exploring it's benefits. A lot of people say they're a necessity in a car like this without really knowing why (This is not aimed at the posters above who raise valid points).
I think that for rapid road use with up to 150bhp an open diff is just fine. Yes, an open diff will allow the car to oversteer. I wouldn't say it was any less controllable though- if anything it's less likely to catch you out because sometimes where a LSD would permit both tyres to break traction simultaneously, an open diff will spin some power off at the inside rear wheel. You tend to have to initiate oversteer with an open diff.

[downsman]

I only have a 125 Sigma engined Seven. Started with an open diff and didn't have any complaints for road and one track day in the first year.
However, I'm not one for hanging the tail out on the road!

Of course my first diff was awful, so I got an old Ford one rebuilt and decided to do the job properly by fitting a Titan plate diff.

This year, I have found it still excellent on the road, I haven't noticed understeer or heavy steering, just a few noises when manoeuvring slowly.
When I had a chance to drive it on the Dunsfold handling day, I found the car transformed and even in my clumsy hands the car was a joy to slide on the slalom

So, while an open diff is fine, I would say decent tyres and an lsd are the best upgrades I have made by far.

[BertBert]

I think that there's far too many positives attributed to the LSD, especially for road use. I certainly don't understand how you get more oversteer with an open diff. As someone pointed out, the open diff actually bleeds power off with the lifting rear wheel.

So I'd not be too bothered about not having one.

Bert

[Noger]

BertBert said:

I think that there's far too many positives attributed to the LSD, especially for road use. I certainly don't understand how you get more oversteer with an open diff. As someone pointed out, the open diff actually bleeds power off with the lifting rear wheel.

So I'd not be too bothered about not having one.

Bert

Spot on. Not *too* bothered. Unless you are maybe trying to protect an Ital diff from a bit too much power.

Nice to have ? Yeah.

Find the right car at the right price and it doesn't have one = end of deal ... No.

If you don't have one will you want one anyway...Probably But if you have one you will just want another shiny bit instead ! Upgradeitis. You are already infected

Fairly easy additions anyway, so run without for a bit, put one one, they tell everyone how you never knew how you lived without

[DickieH]

Guys
Thanks for you re input, thats very useful and at this stage I think i wont 'sweat it' too much if my future prurchase has nt got one.
DickieH

[DickieH]

Guys
Thanks for you re input, thats very useful and at this stage I think i wont 'sweat it' too much if my future prurchase has nt got one.
DickieH

[jcelee]

I've had a ZF on mine for about 6 years and following an overhall by Phil at Road & Race after I bought it it's as quiet as a mouse. My car is a x-flow which probably helps but I'd certainly not discount a ZF on noise grounds, it hooks up beautifully.