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MG Midget and Sprite Technical - Rear Anti Roll bars

Hi everybody

Here's a question to mull over. Rear Anti Roll bars. Here's a pic of me at Harewood Hillclimb coming out of Farmhouse bend. (I did a Driving School day there it was awesome fun). I'm almost lifting a front wheel while exhibiting quite a bit of body roll. ARB is a softened off 11/16 but can be made harder if I need it to be. However, any more front end stiffness means too much understeer on corner entry to be quick, and enough to be alarming.

So - has anyone got any experience of a rear ARB to level the rear off and transfer some corner entry grip onto the front wheels?

I have an LSD so lifting a rear wheel isn't catastrophic but sub optimal.

Eagle eyed people may also notice some aerodynamic modifications have appeared too :)



Rob Armstrong

On a live axle car you are very unlikely to need to fit a rear anti-roll bar. Also you have to consider that roll is bad at the front of the car because it is detrimental to the tyre contact patch with the road. However, with a live axle car the body may roll but the tyre contact patches remain the same because of the live axle.

Daniel

that's true with the rear contact patches, I was wondering if adding roll stiffness at the rear would increase front contact patch by limiting overall body roll - which I don't want to limit roll at the front as it'll lift a front wheel.
Rob Armstrong

I'm sure I've heard of experiments with rear ARB's have led to too much oversteer.

That bend is a nightmare. A dip on entry under braking and then it just seems to go on for ever. It's either understeer or oversteer round there, always seems impossible to get a nice balanced drive through it. If you cock up the entry you are in the gravel and if you drift out towards the exit you're on the grass and then spinning across into the Armco on the inside!
John

I fitted a rear ARB to my frogeye to counter excessive understeer in tight corners such as some at Wiscombe and liked the result, it worked for me but like anything you could go too far with it and end up with oversteer. IIRC my front ARB is 5/8" and on extended mounts and wider rubbers to get more out of it, the standard mounts being somewhat inboard of the ARB bends lead to the ARB bending as well as twisting and losing some benefit. IIRC the rear ARB is 1/2" and was from a Vauxhall Chevette and rebent to suit and is somewhat wider than the front.
David Billington

The Vauxhall Chevette ARB was from the rear of the Chevette and that was a live rear axle car also so I guess GM/Vauxhall felt it was worth fitting.
David Billington

Didn't manufacturers fit ARB to the rear of live axle cars to ensure a car oversteers rather than understeers but ultimately corners slower?
Daniel

The Austin A35 had a rear ARB as standard. I found it lifted the inside wheel too easily, so I removed mine, but championship regs didn't allow an LSD.
Dave O'Neill 2

Rob
Nice pic, I like blue midgets

First off there is a big difference between lifting a front wheel and almost lifting a front wheel
The pic shows yours on the deck but your suspension geometry and body roll have created a situation where the inside wheel has heaps of negative camber and has lifted all the outer tread section off the ground leaving it running on only the inside edge giving you one and a bit tyres on the front compared to two on the back
The easiest way to fix it is to eliminate body roll as much as possible
What front springs have you got in there
600 lb front springs and a 20mm front bar with no push whatsoever - worked for me
If your car suffers from initial turnin understeer but doesn't continue to understeer, try a little bit of toe out on the front--should get rid of it

The secret is to work on the end that's not gripping
If the back is gripping leave it alone or you go slower

You mention you have a LSD and that it wouldn't matter if it picked a rear wheel--all good in theory but two wheels on the ground are always going to be better than one' specially as all lsd's are not the same
Some lsd's loose their lsd effect as soon as a wheel becomes airborne and drive is lost--depends on which type you have

Rear sway bar-easy answer - no no no

In the pic if that is the tightest corner and you were having a bit of a go, it's not too bad; go faster and bend them tyres over a bit and see which end lets go
Seriously though, being a road car, if you don't want to stiffen it right up and wreck it for road use and that corner is your only problem I'd stiffen the front bar up and play with toe settings

With your corner entry understeer, does that continue mid corner or neutralise as you progress into the corner further--??

willy
William Revit

I thought that the chevette used a Panhard rod at the back, not an ARB. Or did it have both?
GuyW

I certainly used a panhard rod, as I got one off a scrapper. I found it in my mother's garage a couple of weeks ago - the panhard, not the scrap Chevette.
Dave O'Neill 2

The basic 'rule' of Midget suspension that has always been preached to me is hard or very hard at the front and soft but well damped at the back.

More importantly Rob - what was your time?!
John

Here is a Luffield Speed Championship winning (Standard class) Midget tackling Harewood - the bend Rob is referring to is the one after the farm buildings.

http://m.youtube.com/watch?v=OFABxlcCbUU
John

And here is me tackling it in my non championship winning Sprite!

http://m.youtube.com/watch?v=ufJ8DlLRYgY
John

The Chevette had both a Panhard rod and a rear ARB as it had coil springs at the rear so needed a lateral axle location device, the Panhard rod.
David Billington

Id look into stiffer springs at the front... i cant see what the back is doing but it lokks fairly decent

O the back what is your set up

Id say a panhard rod is a must and ladder bars wont hurt it maybe avo/sprax adjustable tube shocks

But my understwnding is to keep it well damped but light... to hard and you feel every bump

Looking at the photo... what about extra racing lessons maybe you could alter your driving angles a bit more comming in and out of turns

Im just not sure your photo looks all that bad...

Maybe beef up the front suspention a bit more at the shocks so it damps more
1 Paper

I put one on the back of my Sprite for autocross. After a few events I disconnected it because of snap spins. It was out of service in the photo below.

Charley


C R Huff

thanks for all the info and input, from everyone :)

Current spec is 400lb front springs, these are 1.5 inch shorter, it sits with about 1 inch lower rife height at the front of the sill than the back. 11/16 ARB on the front and adjustable telescopics which were set pretty hard. The rear has telescopics set reasonably soft, a plate type LSD (3J), a second hand RTL mounted vertically and anti tramp radius arms above the axle, like a frogeye. Very big discs on the front, and quite big discs on the back. It's got no axle tramp at all - 13 launches on the hillclimb day and totally unphased by it.

I think I'll start by messing about a bit more with what I've got fitted already - I can change the ARB strength as I made it adjustable. It's already quite leery (especially in the wet/damp on cold track tyres) at the back if provoked so I definitely don't want any more of that... See pic for evidence getting out of shape on the way out of Chippy's (the one at the bottom)

No times I'm afraid as it was a school day - I did get progressively quicker throughout the day from being on the limiter in second (4.2 diff) on the entry to Quarry to being half way through third. Had a total sideways over the line moment, which was alarming, the last corner's a right struggle. I learnt a lot from the instructors and the other guys and girls who were there.

However, watch this space, MSA licence in the post, so some times will be posted at some point this year...




Rob Armstrong

and giving it some on aforementioned big brakes between the farm buildings.

The tyres are Nangkang NS2-Rs, a road legal track day tyre with a reinforced sidewall. I don't seem to be able to get any sidewall flex on them at all but the beakaway is nice. To be honest I'd probably have been better off on the Uniroyal road tyres on the ice rink it turned into with a bit of drizzle.




Rob Armstrong

Similar suspension setup to mine Rob, except I've got lever arms at the front.

Get yourself entered into the Luffield Speed championship, you'll be made very welcome, especially in a road modified Midget!

Let me know if you need any info or contact details.
John

Less weight, less weight to transfer, less roll. How much does it weigh and apart from the obvious what can you do to reduce the weight.
Daniel

Ta John. I'm coming down to Scammonden Dam this coming weekend to get a scrutineer to look over the car - are you popping over? Funds/time will dictate championship rather than the odd day here and there.

Daniel I'm embarrassed to say I have no idea how much it weighs. It's been something I've been meaning to find out but I've never got round to it. I am on a personal mission to get down a bit, so that will help. It had a full tank of fuel (not that helpful). Still has all the carpets etc in but I took everything out of the boot.
Rob Armstrong

Rob
What is your rear spring set-up?

My Sprite also has 400lb front springs 1/2" shorter than standard. I can't remember what the sill height difference front/rear was but I think it was about 1" and there was a definite rake to its stance. It was very prone to 'roll oversteer', especially in the wet - (video of a tank slapper on request! :) )

I fitted 1 1/2" lowering blocks from Peter May this winter - they've made a huge difference - much better rear-end grip, no roll oversteer but slight understeer has returned so I'm thinking of fitting a thicker, 11/16", ARB.

As for hill-climbing - go for it! It's great fun, especially in a Sprite, and a great bunch of folk who will happily give you all sorts of advice and encouragement.

What class will you be running in? If 'Roadgoing Production' a picky eligibility scrutineer might object to the missing bumpers though I think the front air dam / bib will be OK. I was looking to lose a few kilos from my Sprite but the eligibility scrutineer at Loton said the bumpers had to stay. Check the supplementary regs for the events you are thinking of entering.

Let us know how you get on at Harewood and Scammonden..

Colin
Edit
Just seen the photos on the other thread - I don't think the rear spoiler will be allowed in 'Roadgoing Production' - it might bump you into 'Modified Production', which is a whole different kettle of fish, unless there's a pre-1971 class or similar.
Colin Mee

Colin - it runs a 1400 K series and Ford Type 9 box, LSD, all sorts. Fully expecting to be in a class that I'll get thrashed in, but I'll be competing against myself really. Rear set up is standard rear springs, no lowering blocks. It belts the bump stops cross country so no lower at the back or I'll ruin it for road work..... compromise compromise.....
Rob Armstrong

Rob - have you had it over 120 yet?

All race circuits have a working weighbridge and you simply need to ask the scrutineers (very nicely!) if they will weigh your car for you, even if it's not competing at that event. Timing is critical because if they are busy scrutineering or about to have a bunch of cars finish practice/racing and need weighing, there isn't much hope of them having a spare minute or the bridge being free.

If you are at Silverstone 16/17 June you should stand a fair chance of getting your car weighed.
Daniel

" I'll be competing against myself really. "

That's the good thing about hill-climbing and sprinting - it's you against the clock (mind you, it's nice to pick up the odd trophy occasionally). Your local club may well have a handicap based championship with target times calculated from your previous personal best or a power/weight ratio of some sort.

I share my Sprite with my son so, despite the fact we're often the slowest car on the hill, we've got our own competition going (currently it's Dad in pole position!).

I gave the Sprite it's first Sunday outing run of the year today and found that, with the lower back end, it really doesn't like speed humps!
Colin Mee

Ha! I have a very steep drive as well, so any serious lowering mods need to be considered carefully. Car will not be quick at the hill if I can't get it off the drive!

No, I haven't had it over 120. It works out as 20mph per 1000 rpm in top, and I've had it to 5.5k with the roof down. Steady as a rock, small amount of driveline wobble. I sadly can't make Silverstone but will bear it in mind the next time I'm at a circuit.
Rob Armstrong

Rob it doesn't really matter about doing a full championship, only about 25% of the 60 or so competitors in the Luffield do the max 8 events for scoring. Some do a lot more than 8 but most do less, last year I only did 3 and still got a trophy!

There are big benefits for entering a championship (there are others of course!) such as regulations and classes more relevant to your car, competing against similar cars and usually a target system to compete against as well. But the main reason is that a lot of events are over subscribed and the only way to get an entry is to be a competitor in one of the invited championships.

In the Luffield your car would be in Roadging Specials up to 1500cc. The specials bit is because it has a K series. You basically get given a target time for each event and you score points depending on how close you get to it. If you beat it then you score max points and then the target is then calculated on your 'record' for the next year at that venue. It can get quite complicated! But what it means is that all MG's can be catered for and compete against each other reasonably fairly.

There is another championship called Classic Marques which is similar but caters for lots of classics and your target is determined the declared weight and power of your car.

Enjoy Scammonden, it's proper grass roots Motorsport up there! Take a packed lunch and hot flask as there is no catering! I'm sure one of the scruitineers will have a look over your car and maybe ask the competitors as well. I won't be there I'm afraid, I'm taking a break to concentrate on other things this year.

John

John

I seem to remember Ron Hopkinson did a 'handling kit' for midgets - especially 1500's that included a rear anti roll bar - can't find anything on the web with the searches i've tried though.

R.
richard b

Richard

I'm not sure about Midgets, but he certainly did for the MGB.
Dave O'Neill 2

The BL Competition Preparation Manual by MIKE BARRATT
Competition Technical Advisor, British Leyland Motors Inc. (USA) lists rear suspension modifications including an antiroll bar. Unfortunately no details of improvements in handling are given.
Interesting though.


Tony Wood

Rob
Maybe try it with the rear shocks a bit firmer to try and reduce the initial lurch into the corner
What tyre pressures were/do you use

willy
William Revit

No, not a Midget, but our Minor has both front and rear (Morris Ital) ARB's, full hard Koni's at the front, full soft at the rear, stiffer front torsion bars (Marina van), slightly softer rear springs and anti-tramp bars.

Poly bushes everywhere, including the anti-tramp bars, and has a Tran-X LSD.

The handling is very sharp with excellent turn-in, and last year at Castle Combe on the Spring Classic, a professional racing driver took it round for some laps. At the end he said "that thing's ridiculous, it just goes where you point it!".

One thing that significantly helps the turn-in and straight line stability is the caster angle - our Minor has around 5° instead of the standard 3°. Heavier low speed and stationary steering, but superb sharpness.

A few years ago I felt that the steering was less positive than usual, and checking found that one of the standard Ital ARB axle mounting clamps had broken, so no effective ARB - good test though?

Richard
Richard Wale

There is a download for the 'BL Competition Preparation Manual by MIKE BARRATT':

http://www.spridgetguru.com/TA0012_files/MgMdgt1500CompPrep.pdf

Interesting use of the rear damper arms!

Richard
Richard Wale

that's an interesting link Richard - not seen that before - thanks :)

might try messing with the rear settings too :) shame it's such a long time between goes...

Tyre pressures are 20 all round on the track tyres.
Rob Armstrong

I'll pick up on Richard's point about bushes, the condition and/or type.
Nigel Atkins

Damn that looks like fun! Our autocrosses are usually on parking lots rather than a road course. I guess we have too many lawyers over here...
BTW, John, it looks like the non-championship winning car is going around just as well as the winning one!
Jack Orkin

Jack
You need to come down here and play with us
Here's a demo clip of our local hillclimb
It's got over 30 corners and it's fairly steep and fast---and, did I mention fun
willy

https://www.youtube.com/watch?v=ZbFfYobAuM4
William Revit

http://www.youtube.com/watch?v=ZbFfYobAuM4
Dave O'Neill 2

Willy, I'm on my way as soon as I can arrange transport of my Midget!! :) The display of the course and speedometer is pretty cool, too.

Jack
Jack Orkin

Rob
You don't think 20psi might be too low
I had best results with 40 front 36 rear
205/60 Yoki's on 8" rims
just sayin it might be worth a try with them pumped up a bit
willy
William Revit

On my autocross Midget I put a band of chalk on the side wall extending into the tread area. As the tire rolls over on to the side wall it rubs off the chalk. Adjust the tire pressure, reapply the chalk until the chalk just ends at the beginning of the side wall. This gives you maximum contact as the tire tries to roll on to the sidewall. White shoe polish works also but doesn't come off easily.
J Bubela

I've received a video from my day at the Hillclimb School. I can now ignore concentrating on almost lifting a wheel (see pic) HA!

Since then, and having passed scrutineering at Scammonden, there's a race licence in the post and a fireproof onesie in the living room.


Rob Armstrong

Rob,

I would think some more antiroll stiffness would be very helpful!

Below is a picture of the Minor exiting the chicane at Goodwood on an 'MG's on Track' track day - the passenger is a ARDS instructor, who had a unique way of showing which line to take - he just grabbed the steering wheel! Good job the Minor sometimes has a bit in reserve, as a couple of times some 'correction' was required.

Since then the front suspension has been modified to have about 1 of negative camber, which has helped the 'turn-in' noticeably.

Not taking the corner with quite the level of gay abandon that your picture suggests, but I think it does show the benefit of ARB's at both ends of the car?

Richard


Richard Wale

Only one wheel off the ground means you're not trying hard enough!


Dave O'Neill 2

Yeah
Go faster-send more pics

willy
William Revit

OK, go faster pics....
With 179 at the wheels, we find that in 2nd gear corners there's a lot of weight transfer to the rear, as can be seen in the before, during, and after gear change sequence taken on burst
here's 2nd gear


Paul Walbran

Then whilst changing gear ...


Paul Walbran

And then into 3rd and the back goes down and the front comes up again :-)


Paul Walbran

Nice one Paul
Looks like a lively ride-----fun
Thanks for the pics

Here's a fluffy pic (the last one)of my midget finding it's way up our local hillclimb
Shortly after this was taken it found it's way into the trees which decided me to sell it before I did myself some serious damage
Ironically you can't get a start at this hill now with an open car without a full cage
willy


William Revit

An Update!

Managed to compete at Harewood. Managed a 73.74 on my second timed run (3rd run up after a timing meltdown). Rained on the third one.

I've lowered the rear of the car with lowering blocks (had to modify near the rear inner arch to get a bit more clearance) and I've got much less rear roll but still picking a wheel up (just)

Car handles very very well after re-adjusting the RTL and the radius arms.


Rob Armstrong

Rob
It certainly shows you mean business.

Just think of the picked up wheel as reduced rolling resistance!

That photo prompts me to wonder whether, now that you're doing relatively slow, twisty hills, is the wing a help or a hindrance when compared with flat out sprints on circuits? But perhaps that's for different thread! :)

Colin

C Mee

To be honest Colin it probably makes no difference at all!

Top speed up here is probably about 65mph. Wing will be doing bog all at that speed :)
Rob Armstrong

Rob

Looking at that pic it's looking like now might be the time for slightly stiffer rear springs---don't overdo it, one extra 2nd leaf would do the trick
Rating leaf springs is a bit different to coils, to measure them the spring has to be in it's normal ride height position and then compressed and measured from there onwards-you should be looking in the range of 125-145 lbs for a Midget-----depending on your personal taste/driving style of course
I like stiff and had just short of 145 and that was an extra long leaf as well as an extra half leaf in the front half of the spring with 600front springs and a 3/4" bar
It felt like it was on rails--It had initial turn in understeer with the 3/4" bar initially but with a tiddle of toe out that almost fixed that/ then I removed the front mounting plates from the rears prings and extended them to get the front of the spring up as high as possible in the body to level the spring out(can't remember exactly but think it was about 40mm higher)--this completely eliminated any understeer coming into the turn and it transitioned out perfectly under power
Starting to crap on a bit, but they might be something to keep in your memory for future mods----maybe-or not

Interesting--I had a Mazda MX6 turbo a while back which had a standard rear wing and from about 80klm/h (50mph)onwards I could pull the boot release and it just pulled as if it wasn't connected so the wing was starting to work at fairly low speed, I don't know if you,ve ever driven your Midget without a screen, it's surprising how windy it is
I ran mine without a screen and when you get going the wind really sucks on your helmet,I remember my first fast run quite well with the window hole of the helmet going up past the top of my eyes-the strap was a lot tighter second time out

willy

William Revit

Thanks for the tips Willy.

I'm off to find out how to measure a leaf spring poundage

Rob Armstrong

To mearure the 'poundage' of a leaf spring is simple but a little bit to set up

With a coil it is simple
Set your spring on the scales in a press (any press even an old screw down one or anything)Or use your floor jack and jack upwards against something solid
Just give it a little bit of spring compression to take up any slack anywhere
Read the scale--compress the spring 'exactly' one inch and read the scale again--the difference in the two scale readings will be the spring rate lbs/inch
e.g.
25lb initial-compress 1"-400lb===375lb spring

A leaf spring is a bit different as the rate changes as the spring compresses so it is important to have the spring in exactly the same arch as it is when the car is sitting on the ground, so you will need to measure exactly how much deflection there is in the spring and set it up in the press at that same deflection and press one inch from there to measure the rate

OR- cheats method, And this is ONLY for leaf springs--if you don't want to pull the springs out to do it------interested!!!!!
Find a friend that weighs around the same as you or better still two friends that weigh the same
---on a level surface bounce the car down a few times and let it settle then take a wheelarch measurement down to the wheel somewhere(not to the ground as the tyre deflection will alter) then get your twins to sit on the car directly above the wheelarch one on each side and remeasure the wheelarch height
From the difference in height and the twins'
weight you can calculate the spring rate
It's a bit rough but strangely fairly acurate
e.g.
2 people-150lb each = 300lb
Sit them on and car drops 1 1/2"
calculated result = 200lb/inch
Divede by 2 (2 springs) and the result would be a spring rate of 100lb/inch
I know it's a bit crude and the spring experts will be going 'what the he** but it works
Main thing is to have two people that weigh almost the same and an easy total weight to calculate although a calculator can sort that bit--Measuring acurately is the key both weight and wheelarch travel
If one guy is a bit light you can fill his pockets with nuts and bolts and sockets and stuff to make him usefull------------lol
have fun
willy
William Revit

Going back to the original question, when I restored the Minor nearly 20 years ago, I went into the basic principles of 'roll' quite thoroughly, and even part scientifically!

A Minor is obviously not a relative low slung sports car, like a Sprite/ Midget, and in normal trim suffers from excessive roll, with quite poor 'pointing' ability at speed – certainly when compared with today's out-of-the box cars.

My thinking started at the front and I fitted stiffer torsion bars (about 30% stiffer), but what that equates to in conventional coil spring rates is not exact. Very roughly they are 150/200 lb/in, so still quite soft.

Lowering the front suspension by ~2” requires the lower arm to be spaced out by around 3/8” to give 0-1° negative camber, otherwise without the spacing, the suspension goes ‘positive’ camber when lowered. With a fixed length tie bar, spacing the arm out has the effect of pulling the outer end of the lower arm forward, thus increasing the caster angle to ~6°, from the standard 3°. The caster change was not planned, as I did not know at the time what the effect would be, and was rather concerned about how it would handle with its new 1380 engine! The result is quite amazing – the straight line stability at any speed, including in strong winds on the motorway, is uncanny, and the ‘turn-in’ is very much sharper, but the steering at parking speeds is much heavier. A price very definitely worth paying.

Then fitted ‘period’ Koni oil-filled adjustable dampers, re-valved by Koni to uprate by 30% and set to 'full hard'.

Then fitted the stiffest front anti-roll bar that I could find - 5/8" diameter.

Finally replaced all bushes with polyurethane.

The next thing was to create some 'balance' between the front roll stiffness and the rear, so started by making it worse! Softening the 7-leaf rear springs by removing the smallest leaf, and fitting it upside down on the top of the spring to soften and lower the rear by ~2".

Then fitted an ex-Morris Ital rear anti-roll bar (~1/2"), Koni's set on full soft (original valve settings), anti-tramp bars with poly bushes, and of course poly bushes throughout the rear suspension. The rear articulation on roll is more limited, but a Tran-X plate LSD looks after traction very well indeed!

The first time I drove the car after the restoration, it had ALL this on, so I have no idea the effect of each component, but after 2-3 years, I noticed a reduction in steering response and 'pointability' and found that one of the rear anti-roll axle mounts failed, so no effective rear anti-roll bar input.

Apologies for the ramble, and now getting to the point, I think the bits that potentially translate into a Sprite/Midget, are firstly if you increase the front roll stiffness by a significant amount, then something needs to be done at the rear as well, or you end up with excessive understeer, and a very unpleasant car to drive quickly, or really at all. Secondly, increasing the front caster angle by 2-3° has the potential to transform the straight line stability and cornering turn-in.

Richard
Richard Wale

"then something needs to be done at the rear as well, or you end up with excessive understeer" ... or something else to increase grip at the front, such as increased negative camber to give the tyres a better angle of attack.
Paul Walbran

Agree Paul
Work on the end that's not working properly
one change at a time---------
willy
William Revit

One change at a time - absolutely. This is why it takes SO LONG to get things bang on.

One thing I've not messed with is the damper stiffness at the back, something I will play with at the next event (Track day at Castle Combe).

I'll be getting some trackside pictures to see how everything is behaving too.
Rob Armstrong

Here's an update! More front anti roll, a better set of tyres and another 20bhp has resulted in the following cornering attitude


Rob Armstrong

Which, if the right foot is kept buried in the carpet, results in this sort of thing, in which both inside wheels are off the ground (ha). At least I know I'm trying hard.

the smoke is from the rear tyre touching on the inner arch.


Rob Armstrong

Too much of this sort of thing is addictive.

but hammered my way to a new PB of 69.06 this time.

I also met Colin again (hi Colin) and had a good natter.


Rob Armstrong

and just to prove it doesn't always go to plan:

http://www.flickr.com/gp/34910348@N08/Z6sn59

and then sometimes, it does

http://flic.kr/p/29Wnx7k
Rob Armstrong

Hi Rob

Thanks for reviving this thread, I found it very useful first time round and the reminder is much appreciated.

I really enjoyed last weekend at Harewood, a great track with a very friendly and helpful team running it and made all the better for the chance to chat and discuss ideas with you, Rob.

I've still not decided exactly which way to go with the rear springs but will definitely look into copying your idea for beefing up the front anti-roll bar mounting ready for a thicker bar. You might have noticed how my Sprite rolls like a sailing boat in a stiff breeze, especially round Farmhouse! All that will have to wait a while as I'm spending this weekend trying to drive a mini-digger to prepare the way for my new garage!

Any way - here's my best run, only 12 seconds slower than yours!

http://youtu.be/G2SM6JWZRJE

I promise I'll be back to try to narrow the gap.

Cheers

Colin
C Mee

Farmhouse (as mentioned above) is a nightmare. Bumps mid corner unsettles everything and mine does the same as yours, which is to get a bit of a roll on. I end up picking wheels off the ground.

That's a good vid though! And you kept it on the black stuff all day, which is more than I managed!
Rob Armstrong

Fantastic stuff
Rob, your car is sounding like a nice angry little jigger now, good to see the results of your work giving you some results - fun
enjoy it--
Ol' mate Prop would have been impressed with your dashboard/gauges-!!
Cheers
willy
William Revit

It's going well. Next plans are to try and keep all the wheels on the floor without driving it slower!

I had quite a bit of arch catching so that needs looking at.

All good fun anyway. I'm sure Prop would have enjoyed the videos.
Rob Armstrong

Rob,
what gearbox do you have?

(And what's that wide thing above Colin's helmet?)
Nigel Atkins

Nigel
I think Rob mentioned somewhere he has a Type9 box
I'm thinking that Colin has a strip of tape (sunshade) on the visor of his helmet
William Revit

Cheers Willy, I thought it was a T9 but couldn't remember for sure and if the ratios had been changed.

I think Colin's car might be wearing a hard hat in case of falling masonry from the farmhouse(?).
Nigel Atkins

It's a Type 9, a V6 one. I also run a 4.2 diff.
Rob Armstrong

Cheer Rob
2.3 or 2.8?

(I'd forgotten the 4.2 diff, remembered the LSD tho')
Nigel Atkins

ooho. It's from the 2.8 I think.

If one of the links above doesn't work (or if they are the same), here's a public version of my trip into the green stuff.

http://www.flickr.com/photos/34910348@N08/44234325394/in/photostream/
Rob Armstrong

It's simply a black strip that was across the top of the visor, it barely intrudes into the opening when the visor's down so you don't really notice it.

With the soft top down I have to run with the visor down but with the hard-top on and the window wound up I can have the visor open.

With the hard top on it gets pretty hot in there with three-layer fireproof overalls, boots, gloves and a helmet on. Some times, if there's been an 'off' or a 'fail' you're sitting in the queue for the start for ages and, even with the engine off, you can be roasting, so a bit of ventilation's most welcome.
C Mee

last year at Silverstone (MG Live) it was 29 / 30 degrees and I simply had to run without the roof on, even then I was sweating buckets with a black helmet and black suit. My suit is simultaneously outrageously hot in the sun and curiously cold if the wind blows. What an odd garment.
Rob Armstrong

Thanks for the replies.

Rob I only asked about your T9 as the 2.8/9 have different ratios that are slightly different the the other T9 and Spridget boxes.
Nigel Atkins

Huh, I never knew they were that different. Remember counting input shaft teeth at some point :D
Rob Armstrong

Rob,
on the T9 first gear is is bit (low or is it high?), even on my 1275 if I pull off very smartish I soon get to 5,500 rpm, which I know would be low revs to you but anything above 5,000rpm is a waste of time with mine (that's with a 3.9 diff and standard tyre size).

In case you weren't joking, fyi standard gear ratios -

T9 2.8/2.9 V6 -
first 3.36, second 1.81, third 1.26

T9 (petrol) four pot & 2.3 V6 -
first 3.65, second 1.97, third 1.37

1275-
first 3.2, second 1.916, third 1.357

T9 early diesel -
first 3.9, second 2.32, third 1.399(?)

T9 P100 & late diesel -
first 3.9, second 2.29, third 1.38

Obviously you can achieve higher revs quick on grass.


Nigel Atkins

Useful info, thanks Nigel. I knew about the different ratios, but not that there was 2 different types of V6 boxes
Rob Armstrong

Rob,
I didn't either until very recently.

I've forgotten far more than I ever knew, luckily I knew very little - that I can remember.
Nigel Atkins

This thread was discussed between 06/05/2017 and 04/10/2018

MG Midget and Sprite Technical index

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