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(Post Link) post #1 of 16 Old 12-03-09 Thread Starter
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Hmmm Q2 or not Q2

Please can someone explain to me why I should get a Q2 Diff ?
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Re: Q2 or not Q2

people say they are great but id only consider one if my original stopped working. i cant see the point unless you do track days
 
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Re: Q2 or not Q2

Mark ,fitting aQ2 will transform your car !
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Re: Q2 or not Q2

You get more of the torque from the engine onto the road through the tyres. If you corner fairly quickly then you will notice the difference as it takes the power from the inside wheel and transfers it into the outside wheel meaning that you can corner faster and with more confidence. It also means that on an uneven roads then you're getting more of the power through to the road.

I test drove a car with Q2 and without when I was looking to buy and couldn't believe how much of an improvement it is.
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Re: Q2 or not Q2

On a related note - does anyone know if insurance companies charge more if you have the Q2 fitted. I'm still dreaming of a GTA SW

Theoretically it should make handling more predictable and safer - bet they charge more tho :/
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Re: Q2 or not Q2

If you dont get it your diff could blow a hole in your gearbox!

The difference it makes is immense though.. I couldnt believe it after fitting it to my gta...

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Edit: As jamieboy said.. doesnt make a difference to normal driving.

Last edited by OperationAlfa; 12-03-09 at 15:26.
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Re: Q2 or not Q2

It makes a noticeable difference when you're cornering enthusiastically.

It doesn't transform your car from being rubbish to being brilliant, and I do think that sometimes its benefits get blown out of proportion a bit, but it is definitely worthwhile.
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Re: Q2 or not Q2

Well, I have taken the plunge and the car has gone in.
2 reasons why I did/wanted it done.
1) The stories of the Diff popping and smashing it's way through the gear box. For 500 quid I have that peace of mind of knowing I'm not looking to spend a few grand on the damage it MIGHT cause. Also like to think the next owner will benefit from it and no one can say I never neglect my car/s

2) When on my last run out with the club, I was giving more than I normally would and I'd say it felt a little wide on corners.

I will take it back to the same route after to see the improvements of course!
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Re: Q2 or not Q2

An open diff delivers equal torque to each wheel. When you go round a corner, the car experiences lateral load transfer, ie more of the car's weight is over the outside wheel than the inside. With an open diff, as the inside wheel goes unloaded (as less weight is going through it round the corner), the wheel has less grip.

A limited slip diff will transfer more torque to the wheel with more grip. Going round a corner, this means some torque is effectively taken away from the inside wheel and transferred to the outside wheel, which has more grip - the outside wheel will make better use of this torque as it is being pressed into the road harder than the inside wheel.

The result of this is more efficient delivery of power from the engine and transimssion, to the road.

In simplified real terms, if you're on a constant radius turn, ie a roundabout, as your speed increases your car with an open diff will be more inclined to understeer, ie you need to apply a larger steering input to maintain your heading as the car tries to go straight on.

With a limited slip diff (Q2) fitted, these understeer effects don't kick in until you're going much faster. This means that at a given speed, the car will grip much better with a Q2 than with a standard diff. The effects are far more pronounced in situations such as this, where the car is cornering fast. In 'normal' driving it won't have much of an effect - however when cornering fast you will be able to put much more power down (ie accelerate more) as the wheels will grip much more efficiently than with a standard diff.

Basically it makes it easier and safer to drive the car fast, as it won't lose grip until you're doing a much higher speed.

Fundamentally - it's amazing

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Re: Q2 or not Q2

On our 3.0 GTV. it transformed the handling. Front seems stiffer and the car tightens the corners. DO IT ! and clutch if needs be. We informed our insurers , no increase and no loading on renewal. All the best.

Last edited by guiliasuper; 12-03-09 at 17:52.
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Re: Q2 or not Q2

You won't be disappointed if thats what your worried about.

The big traffic roundabouts like on motorway junctions become much more fun with the Q2.
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Re: Q2 or not Q2

Thanks all for your help....I Think it's got to happen after hearing all that. Will keep you posted.

Thanks again
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Re: Q2 or not Q2

Quote:
Originally Posted by v6hughes View Post
people say they are great but id only consider one if my original stopped working. i cant see the point unless you do track days
If your original "stops working" you're looking at a grand at the absolute minimum, possibly as much as £1500 depending on the damage it does, to get it fixed and have a Q2 put in. Its a bit like saying "I'll not change my cambelt til it breaks", except theres a bit less chance the original diff will go. But if you had a GTA I bet just as many people have had a diff let go before 72k or 5 years as a cambelt.

Quote:
Originally Posted by G5een View Post
You won't be disappointed if thats what your worried about.

The big traffic roundabouts like on motorway junctions become much more fun with the Q2.
I'd not have a big power FWD car again without an LSD, unless it was just some big barge to get me to work and back like an Omega or summat. Even if I buy a 1.9 JTD in the future it will be getting the Q2 treatment

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Re: Q2 or not Q2

You won't be disappointed if thats what your worried about.
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Re: Q2 or not Q2

Quote:
Originally Posted by Pud237 View Post
I'd not have a big power FWD car again without an LSD, unless it was just some big barge to get me to work and back like an Omega or summat. Even if I buy a 1.9 JTD in the future it will be getting the Q2 treatment
Totally, FWD makes more sense with a LSD.
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Re: Q2 or not Q2

As long as you've got enough power to warrant it, get it fitted.

Yes, it will be a little more snatchy, and you will spin both front wheels through 1st and 2nd (if you've got enough torque) but it will be so much better than a car without one.

If its on a 3.0/3.2 petrol, then it will work perfect, and should really be 100% worthwhile.
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