Couple of Mini Questions

Couple of Mini Questions

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ace-T

Original Poster:

7,721 posts

257 months

Thursday 6th January 2005
quotequote all
Hi all

Just wanted to pick your collective brains on a couple of issues.

Tyres

I know the roads are damn slippy at the moment so I am being careful anyway but since I got the new tyres I have noticed that under slightly heavier than normal braking the mini just slides They have done a couple of k so it is not the new tyre syndrome. Judas even managed a four wheel drift while getting across a busy junction The tyres are Bridgestone B390's and were slightly over inflated at 30 intead of 28 (a more accurate tyre presure gauge was a wise investment ). Would this make such a significant difference?

Vibration

Noticed today the car seemed a lot more noisy when I started it up. Pressing the accelerator in neutral seemed to make the vibration noise more quiet though. It seems to be coming from under the right wing. Nothing appears to be loose and it is outside the car rather than inside. Any ideas on what to check?

Thoughts or suggestions much appreciated.

Ace-T

miniman

25,174 posts

264 months

Thursday 6th January 2005
quotequote all
Not sure about the tyres, but the noise from the front wing could be the fresh air hose which runs from the engine bay (just in front of the clutch housing behind the rad), through the wing, and into the cabin. Could be loose, perhaps? A bit of revs would stop it resonating and quieten it down.

HTH

PS - have you got lots of good hints from your Trinny & Susannah book?

ace-T

Original Poster:

7,721 posts

257 months

Thursday 6th January 2005
quotequote all


I think there were others at that particular event who were in more need of the advice than I was

Thanks for the help anyway James! The air hose came off the passenger side and wore right through! Didn't occur to me it would be the same thing. D'oh!

I am considering doing some Auto testing in the Mini too and am wondering whether upgrading the suspension would be the right first mod, what do you think?

Ace-T

miniman

25,174 posts

264 months

Thursday 6th January 2005
quotequote all
ace-T said:


I think there were others at that particular event who were in more need of the advice than I was
Quite. I seem to recall a tasty turquoise number... or is that "tatty"?

ace-T said:
The air hose came off the passenger side and wore right through! Didn't occur to me it would be the same thing. D'oh!

There's one on the other side???

ace-T said:
I am considering doing some Auto testing in the Mini too and am wondering whether upgrading the suspension would be the right first mod, what do you think?

Suspension or (preferably AND) brakes first. The traditional combo is Spax / GAZ adjustable shocks and Hi-Los (I have this on mine) or you could go for coilovers (more expensive). Lots of people will tell you different about how to get it to handle. Cooperman wrote an article about it which is now on my website:

www.minispecial.com/technical/showarticle.asp?article=1

Then you can go for uprated brakes - either go to 7.5" Cooper S discs and calipers and fit 10" rims (better handling than 12s or 13s) or go for some 4-pot calipers from a Metro or even some lovely alloy KAD numbers (£400 upwards IIRC).

Also well worth a look in Minimax's "what to spend £500 on" thread as Peter is handing out some useful handling tips in there at the moment too.

HTH

RickApple

429 posts

237 months

Friday 7th January 2005
quotequote all
Aside from pumping the brakes, is there anyway to increase the efficiency of stock brakes - i have the same problems when applying moderate pressure, the thing gets loose around the rear and slides sideways. I dont use it in the wet anymore! Would uprated mini fins on the rear drums do anything?

miniman

25,174 posts

264 months

Friday 7th January 2005
quotequote all
RickApple said:
Aside from pumping the brakes, is there anyway to increase the efficiency of stock brakes - i have the same problems when applying moderate pressure, the thing gets loose around the rear and slides sideways. I dont use it in the wet anymore! Would uprated mini fins on the rear drums do anything?

Sounds more like the weight is being thrown onto the front wheels and the rears are locking up too easily. Stronger rear brakes would make this worse, rather than better, I think.

What say you Cooperman??

DodgyDave

810 posts

253 months

Friday 7th January 2005
quotequote all
Id check the rear brakes are actually working first.
If there is a blockage or the pipe under the car has been flattened then all of the break pressure would end up at the front. (This is a guess)
Jack the back up and get someone to sit in and gradually press the peddle to see where and how much braking is applied to the rear.

The process of elimination is always the key to fixing problems! In my experience anyway.

not love machine

7,609 posts

237 months

Friday 7th January 2005
quotequote all
Huddersfield spares do a pretty good line in cheap, good suspension setups. Avoid their rear camber brackets though. (get adj track/camber as shimming them is a pain). Rear anti roll bar is the best thing on my car. Makes it corner properly!

If you are on a budget, go to miniclassic.co.uk and find the Fiesta Mk1 calipers thread.
I run S brakes myself and at £230 they were a rather expensive starting point (needed a TOTAL rebuild).

Fiesta callipers are meant to WORK with 10" wheels, they work well but they are not S callipers. It's rather like having a MG Metro engine in your 65 cooper S.

guru_1071

2,768 posts

236 months

Friday 7th January 2005
quotequote all
if your rear brakes are locking up you could try fitting the smaller pre 1969 cylinders (or even the 1/2" bore metros ones)

ive never seen a fiesta with 10" wheels???. i dont see how a single sliding piston can be more efficant than a solid twin pot either.

you could buy a brand new set of s calipers and all the bit you need to convert a 12" car to 10" brakes for £305.

love machine

7,609 posts

237 months

Friday 7th January 2005
quotequote all
No, they just use the sliding calipers. Personally, I hate sliders. I would have a set of S brakes anyday, but for press the pedal, wheels try and stop turning, they are very good.

That sounds like a good deal.

cooperman

4,428 posts

252 months

Monday 10th January 2005
quotequote all
The question seems to be whethre it's the new tyres causing the locking-up or a braking system fault.
First let's consider the tyres. Personally i've never liked the Bridgestone offerings since I had a set on a 1071 'S' rally car a few years ago in 165/70 x 10 size. Everyone who drove the car in anger in the wet managed to spin it (myself included). I've had much less problems with Yoko's, Falkens and even Colway rally remoulds. For optimum pressures in terms of grip and handling I usually run at 32 to 34 psi all round.
What tyres were you on before changing and how did the brakes perform on them?
If it's the brakes, then we all may need to think again. For example, do all 4 wheels lock up, or just the fronts, or just the backs? You may need to get someone to stand outside the car and watch the wheels under heavy braking. You can get an adjustable rear bias valve for single circuit cars, but the dual braking systems cars may be different, I have always run standard brake cylinders and valves on later cars without a problem. Maybe you have a later car with the pressure relief valve on the front bulkhead. This unit could be defective. Remember, if you change this and have to change the brake pipes, the threads in the valve are metric, whilst those at the rear cylinders/T-piece are imperial (stupid, but true!!).
Good luck with sorting it out. i hope this helps,

Peter

ace-T

Original Poster:

7,721 posts

257 months

Tuesday 11th January 2005
quotequote all
Thanks for all the replies guys

James, I got the Demon Tweeks catalog with a magazine the other day and I spent lunchtime trying to figure out what bits I needed (not fully conversant with the terminology yet...but will persevere ). All the blokes thought I was , all the girls thought I was a !

Peter, the tyres before were the 3 original 1997 Pirellis and one Nankang(?) on the back. IIRC these were much worse in the dry but seemed to have been much better in the wet. (Or it may have been I was driving it more slowly anyway! )

When you say about dual braking system, what do you mean? The car has got disks on the front and drums on the back and is a Mini Equinox 1.3. Do you know where I could find out about what braking system it has?

Your help and advice is much appreciated!

Ace-T

miniman

25,174 posts

264 months

Tuesday 11th January 2005
quotequote all
You'll get a lot cheaper than Demon Tweeks for Mini bits. Buy a copy of Mini Mag / Mini World. There are dozens of suppliers in there who are real specialists. I get all my bits from Somerford who are by no means cheapest but have **everything** in stock, down to the last nut and bolt, and are a 10 minute blat from my house.

Your braking system is almost certainly split front / rear. Follow the brake pipes from the master cylinder / servo and you should find a gold-coloured valve unit attached to the body just down near the clutch - it will have 2 feeds going in and 2 feeds coming out and heading off to the front and rear of the car. This is the bias valve which reduces the pressure to the rear brakes.

miniman

25,174 posts

264 months

Tuesday 11th January 2005
quotequote all
ace-T said:
(not fully conversant with the terminology yet...but will persevere )

For the suspension you will need a set of hi-los, a set of dampers and ideally a set of knuckle joints. Plus you will need a suspension compression tool to fit the front hi-los.

The hi-los are the adjustable height bit. They replace the standard suspension trumpets with adjustable versions. You can get "original" hi-los or copies. Probably about the same as buying a "genuine" Hoover vs. an Electrolux!

You can go for adjustable dampers or self-adjust. I have Spax but Gaz and KYB are quite well rated also. The adjustment lets you stiffen them up with a screw, as it were... If you are going to lower the car, get lowered dampers (i.e. shorter ones). Spax are the same price as regular. Lowering it will not do wonders for the handling or comfort - it's a looks thing.

The knuckle joints connect the hi-los to the rest of the car, basically. The ones on the car will probably be knackered so worth changing them whilst it's all apart. Get yourself a blowtorch to remove the old ones. Really.

love machine

7,609 posts

237 months

Wednesday 12th January 2005
quotequote all
If you want to nail it around corners at a ridiculously high speed, lower it until the tyre is an equal distance from the wheelarch. There is a chance that the back wheels will bind the arches and so I used an anti roll bar (14mm) to stiffen it up more. I run adjustable everything (Huddersfield Spares) and am running -2deg camber front and -0.75 rear with the track straight ahead. I can take a 90 degree bend with 10ft each side at about 60mph. It is seriously fun to drive. Running sticky tyres on 10" rims.

Lower it, it makes it stay flatter through the corners and reduces understeer.

cooperman

4,428 posts

252 months

Thursday 13th January 2005
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Personally I would never lower a road-going Mini. There is little enough available suspension travel to begin with and for normal road use any reduction is available suspension travel is a retrograde step in overall handling.
If the car is a racing or hill climb car, then that's a different matter, but for road use to lower it is to gain almost nothing whilst losing handling on bumpy back roads and reducing ground clearance making damage to sump and exhaust system more likely.
I don't think you'll find better road handling Minis than the competitive rally cars and they are all raised slightly.
The main thing is the suspension settings, which should be measured accurately and have good bushes, and damper settings, which should be neither too soft nor too hard. Many people set their dampers hard, but this is not necessarily the right thing to do.
Always remember, with the suspension on the bump stops, the car won't steer properly.
'Dodgy Dave' will tell you how much his car improved after we raised the ride height and set the rear camber and front tracking.