about to buy a Stuart Taylor r1 hill climb car it has a 4.1 LSD but I want to use car for track days so what it as competive as poss so which diff would best suit a 3.6 or 3.9, LSD or non thanks for any advice

Which tracks are you going to be doing most?
Somewhere around 3.38 may be a good starting point.
3.62 may be ok if slightly slower tracks!
What speed is it topping out at now? Have you spoken to Philip about it?
Also as your not too far away, pop up to barbon hillclimb Saturday 13th June. You'll have a great day watching g and chatting to people as the paddock is open to spectators all day. Make sure to pop over and say hi and I'll introduce you to a few of the others!

i would run 3.62 if it was me

You can also keep the LSD unit inside your diff and get the ratios swapped!

I've got a 5vy in my Fury and run a 3.21:1 Freelander diff. Little bit over geared on track but fine on the road; 72 in first, 7000rpm at 70mph in top and theoretical top is 149 and though never done it, been past 140 still accelerating.

In a seven with less aero you probably want a 3.38 or 3.6.
4.1 is very low and 3.9 not much better.

My thinking is a 3.62 will see around 125mph. Maybe a tad less.
I'm not sure a 1000cc BEC seven will pull more through the aerodynamic barrier on any UK tracks anyway!!

Ty croes and oulton will be the tracks I will be using

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Originally posted by daniel mason
Which tracks are you going to be doing most?
Somewhere around 3.38 may be a good starting point.
3.62 may be ok if slightly slower tracks!
What speed is it topping out at now? Have you spoken to Philip about it?
Also as your not too far away, pop up to barbon hillclimb Saturday 13th June. You'll have a great day watching g and chatting to people as the paddock is open to spectators all day. Make sure to pop over and say hi and I'll introduce you to a few of the others!

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Phil said it's topping out around 110 with the 4.1

Is it live axle ?
If so 3.5 is about your best bet.

I'd try to be ill on the 13th if I were you
I thought you'd say oil ton and anglesey from your locationa nd both are very fast and would suit he 3.38 better I think. If you were thinking of getting some overalls and gloves and doing some speed events like Philip was on the hillclimbs and sprints, I'd say 3.62 as they are at smaller slightly slower venues!
A very good event to come to would be blyton sprint weekend in July. It's organised by westfield and is part of there large speed series. 3 of the fastest bike engined 7's I've ever seen will almost certainly be there,along with many other kits and they do a track day on the Friday for anyone interested! Its a cracking weekend of sprinting and me and Jeff w will be there again from this forum. I'd estimate at least 60 x 7 type cars will be competing on the Saturday and Sunday as well as us guys in various racing cars!

I hunk they are an IRS chassis. Mine was anyway

when in July? I also pop up you're way a lot as my bro runs pub in morecome

Some rough pubs in morecambe mate!
Friday 10th is track day but it will be empty as most are travelling up for the sprinting which is Saturday 11th Sunday 12th!
Last year there was about 3 cars on track most of the day on Friday so loads of room to push hard if needed!
I'll be going down early Friday from here and hopefully getting there around 11:00am

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Originally posted by daniel mason
I hunk they are an IRS chassis. Mine was anyway

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I don't normally get any issues :-) also there a dîfference in diffs as saw there are xr4x4 and normal diffs for sale can I use any?

No. There are different sizes. 7" and 7 1/2" and there are push in and bolt on shaft types!
I would remove the diff and send it to road race transmissions to get a 3.38 ratio I to your LSD diff

you're gona have to pardon my stupidity but live axle?

Says IRS rear on the advert with a 4.27 Granada diff

There's a 7.5 on at moment but spoke to Phil and he said a 7" 3.6 LSD would be fine ?

This what he put to me - A 7" diff is a lighter unit and best for the car a 3.62 ratio is better for road use/track day as an all rounder 3.92 for a bit more acceleration but less top end the 3.62 and 3.9 with an LSD has 100m flanges with ring of bolts which I explained to you on the phone this will make the diff swap easier as a non LSD has CV joints/drive shafts are different which slide into the diff making it more difficult to install.

You want it geared for 125-130mph or you will just sit on the rev limiter on the straights watching cars go by.

3.6 too high?

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Originally posted by craig5
you're gona have to pardon my stupidity but live axle?

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Originally posted by craig5
There's a 7.5 on at moment but spoke to Phil and he said a 7" 3.6 LSD would be fine ?

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6mm spacers?

3.38 would be better on the road and long tracks like oulton. 3.62 possibly at sprints or short tracks like blyton!
Like I said yo can get a ratio put into your 7 1/2" diff then just bolt the diff back into the chassis with no messing around

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Originally posted by craig5
3.6 too high?

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Originally posted by mark chandler

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Originally posted by craig5
3.6 too high?

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My humble blade engine ran out of revs with a 3.65, you need to be targeting the highest ratio you can obtain IMHO

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quote:

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Originally posted by daniel mason
3.38 would be better on the road and long tracks like oulton. 3.62 possibly at sprints or short tracks like blyton!
Like I said yo can get a ratio put into your 7 1/2" diff then just bolt the diff back into the chassis with no messing around

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3.14 LSD in mine now, 1st gear overcomes traction from my slicks when sprinting, I notch up to maybe third gear on the straight bits.

A lower diff, say 4.1 would mean I would be pulling away in second or third and driving in 4th to 6th as gear changes cost time.

You have to balance with your engine, a low ratio diff, 4.1 would not be nice on the road.

http://pages.ebay.com/link/?nav=item.view&alt=web&id=111200999094

Is that what I would need to go to 7" from 7.5"?

think of a washer but 6mm thick.
Not sure how the diff is mounted in your chassis but you'll need at least 4 of these.

why would I need 4?

One at each Side mounting point.
Whilst I understand what mark is saying with gearing, I disagree! Rattle through the gears as fast as you can and make use of the cars acceleration!
This is my mate Bradley doing a hillclimb,he gears his car to get through the box fast and he's mega quick! He fires through the box in no time
https://m.youtube.com/watch?v=JEaqKwBmvJ8

Think my head is fryed lol I always thought the diff between the 7 and the 7.5 was the caseing

just spoke to Phil and this is his reply - so???

Hi Craig

It doesn't need any spacers as diff is held in a cradle mounted at front in tunnel and rear bracket across the diff and bolts to chassis - see pictures.

thanks
Phil

Maybe I,m just to old, turning bends and changing gears gets a bit confusing and mucks up my lines on sprints, on the track I'm fine as plenty of practice.

why would i need 4 spacers when there only 3 mounting points?

I'm assuming he thought it had 2 mounts each side meaning 4 x 1/2" spacers

daniel what size spacers would i need as seen people saying use washers or a nut but that wouldnt be safe would it

alot of people use washers,

look at this picture and it may help you out..

Washers may be better,or a spacer plus a washer?
You obviously need it tight with no play at all, but don't want to be bending the diff mounts due to incorrect sized spacers,it need to fit properly.
Personally I'd have just bolted in another 7 1/2" unit as suggested before,but now you gave the 7" unit your just going to have to make it fit

my system totally different to that i have a craddle front and rear

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Originally posted by craig5
my system totally different to that i have a craddle front and rear

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hi kev couldnt find a 3.38 but im on look out but dont mind gettin a collection of diff always handy in times of needs regards diff im in work now on lathe so hopefully within the hour be ready to try again

My diff is currently being rebuilt with a 3.38 cwp

Bought the 3.38 diff off EBay from Estonia, £200 delivered

well diff is in :-) just got to get correct height of front to engaged reverse electric motor

car is back up and running :-)

Nice one

Where abouts in North Wales are you?

Northop hall few miles outside mold

Did you go for a 3.62 or a 3.38 in the end?

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Originally posted by craig5
Northop hall few miles outside mold

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Got a 3.62 in at moment but will still keep eye open for a 3.38, be good kev happy to meet anytime if you want to try my STM

ive noticed a issue with fitting new diff, the front of the diff has a craddle and the 2 bolts that connect it to the diff keep come lose and hitting my reverse motor any ideas?