What now???

I've just fitted 350 quids worth of exhaust kit to my ax, including a 4>1 manifold and a janspeed system.

Thats it, project over ... everything else that would increase bhp has been done, crap that won't hasn't (blue leds, bodykit, big music box,etc). Its even got lower gearing than it should have.

So what now ... spend another 2k modifying a vts engine and plant that in the bay or just run this 1.4 litre to the ground whilst saving for the next project car???

Reply to
FEo2 Welder
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Yep, i suppose i could try the mg maestro twin webber conversion, just doing that on a standard axgt is supposed to increase bhp from 85>100. Would it require any adjustment, apart from the basic idle mixture, i mean, would it need a rolling road tune up???

I might look into upgrading the brakes with the gti kit, also maybe a quick shift kit as well. A proper internal roll cage might be another idea. I won't be doing any external bodywork modifications ... the ax is hardly a pretty car to start with.

Although the performance modifications have all been worthwhile ... i fitted a kent cam to an old style bmw some years ago (mechanical fuel injection and adjustable timing) ... they promised another 15bhp over the stock

125bhp. Ok, it might have gained 15bhp, but you really don't notice it much on such a lardy assed car (1280kg). So i decided that would be my last big car modification. Then i bought the lightest hatchback i could find, and apart from various bits of trim falling off, its been quite entertaining.

Must go check out ebay for that twin webber..........

Reply to
FEo2 Welder

Eh?? No, that would end my enjoyment of the car quite quickly.

Nitrous is for proper engines, not for souped up shopping trolley engines (even if i do say so myself).

Could work well on my 11:1 compression 2.7 litre 6 pot bmw ... which is also lower geared than it shouild be.

Maybe even the 730i ???

Reply to
FEo2 Welder

I don't think upgrading the rear brakes would be of any use. The thing does what we all did on pushbikes when we were kids (you know ... brake hard and make the back end lift off).

Good on wet corners ... sort of like doing handbrake turns, without pulling the handbrake!!! (Yes ... i have replaced the wierdo valve thing on the beam, waste of time that).

The front drums are solid, i'd imagine 205 gti kit would go straight on. Obviously i'd loose the three bolt hubs in favour of four bolt hubs, meaning the three stud wheels would have to go. (Keeping in line with my policy of spending only on the bits that make it faster, alloys were never fitted, so i'd be swapping steel rims for steel rims).

Reply to
FEo2 Welder

what? by pushing the rear brake? i think not.

Reply to
Theo

Was about to mention that - the GT came with standard alloys...

Reply to
Dan405

The very first gt's had steels, with a wierd plastic bit that clipped in the middle of the wheel (grey with red line around it). Its actually quite a hard rim to find .... i had a hole rust through one and had to scour loads of scrappies to get another. PLENTY of gt alloys around, but they all wanted 80 quid for a load of corroded aluminium. And even more one litre rims are around .... they really do look narrow!! I've got an article here about the axgt, in a caravan magazine. They did a review about it as a tow car. Back in 1988 there was a caravan of 500kgs which the car is suited to. The reviewer noted the car is prone to wheelspin, but has a very useful second gear. And he was able to get into top. Same trim as mine inside ..... and ..... naff looking steel wheels and a "low" mounted rear spoiler. (I think all of the later ones put the spoiler higher up).

Reply to
FEo2 Welder

No i meant yank the front brake ... make the back wheel leave the ground. Didn't you have a chopper bike once????

I can also make one rear wheel leave the ground, so my mate tells me when he followed me once round a twisty road. ....... Although you only have to jack an ax 2 inches to get the back wheel off the deck.

Reply to
FEo2 Welder

Alloys DO make it faster, cos you can get wider ones with the appropriate wider tyres !

Bike-style steel rims are loonacy - change them at once :)

Reply to
Nom

Isn't aluminium weaker than steel. Don't they use more alloy than you would steel to get the same strength in a wheel.

End result = alloy wheels are heavier than steels.

The alloys i've had on bmw's over the years were always heavier than the factory spec. steels anyway.

Obviously (or not) a nice open plan alloy wheel (4 spoke maybe) would reduce the effects of a side wind on a car.

Reply to
FEo2 Welder

No - not if you get some REAL alloy wheels - Oz's Super Legeras for example are specifically made to be as light as possible. You'll have to swap your hubs with a 205 GTi though - your current choice of

3-stud wheels is approximately zero.

Having said that, Compomotive's white MO rim is available to fit PSA 3-stud cars :

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- as a proper motorsport rim,it's fairly light - and you could get a wider one than your currentsteelies, complete with 195 rubber. You also get MUCH better brake cooling with a nice open-plan alloy !

Reply to
Nom

So i could spend 400quid plus on "good alloys" to loose a few pounds in weight, or spend the same on the engine doing further modifications.

2% less weight or 5% more flywheel horsepower???

I could pull the engine, strip and rebuild the bottom end, including having the crankshaft and flywheel lightened, then upgrade the head further .... its already been ported, but the kent cam and new rockers in there are compatible with dual valve springs. Basically increasing the maximum revs of the engine ..... maybe adding a slight bit of torque in the process, but the fact it could run an extra 1000rpm in any gear would aid acceleration.

Nah ... i'll leave as is, will put aome nice alloys on my 730i instead!!

Reply to
FEo2 Welder

you can get all that for 400 notes?

Reply to
Theo

I could. Besides ... i have some very decent engineering machines at work. The capstan lathe would easily chew 3mm off the 12mm flywheel for instance!! Lightening the crankshaft/polishing/balancing would be done by my local engine re-manufacturers ... possibly the dearest bit. Bearing shells/rings/oil pump and chain/lower gasket set would all be sourced from eurocarparts or andyspares. (100 quid). Have a set of B.E. bearing cap stretch bolts and a set of head stretch bolts new and unused on the shelf. Also oils and coolants new and ready in the shed. (Need oil filter). The dual valve springs kit is about 80 quid. Headgasket from main dealer is 34 quid.

Lots of stuff on the lump is virtually new anyway .... water pump and gasket, all head seals, fuel pump,rockers,shafts,kent cam,etc. Not as if i would be stripping an early metro engine which has never been opened up in its 20 year old life .... rusty snapping exhaust bolts and all.

Labour charge doesn't exist ... i do it. Besides, my engines tend to keep going, an engine built by a mechanic who drops tools when the tea break bell goes, tends to be sloppily built (installed) ..... e.g: not all the bolts get tightened!!!

Reply to
FEo2 Welder

You don't get a bigger contact patch. You use a softer compound because there's more tyre there to wear, hence you can produce a tyre with the same life and more grip.

Reply to
Doki

Ah fuckit, this is the sort of thing easier argued over a pint than on here!

From that WRC site: Myth 1: Wider Tyres = More Rubber on the Road The area of the contact patch is a function of the load on the tyre and the tyre pressure alone - almost exactly. In other words, if you make a tyre wider, but keep the weight of the car, and the tyre pressure the same, the contact patch area will not increase. It will simply get wider and shorter.

From a Mini site:

145 x 10 Front - 28 Rear - 26 165/70 x 10 Front - 24 Rear - 26

I say if you fit wider tyres and optimise them and the car then you have more physical contact with the road (apart from in the wet, due to the nature or water!) hence more grip. I agree if you simply throw on a set of Wankfords allies your handling will go all to hell, for a plethora of reasons.

And I never said wider tyres would run at the same pressures as narrow ones....

Reply to
Stuffed

Correct.

The area of rubber touching the road, remains exactly the same, not matter what the tyre width. But the shape of this contact-patch changes with width - it becomes both wider and shorter, as you increase tyre width. The wider the contact patch, the more lateral (cornering) grip you get. The longer the contact patch, the more longitudinal (acceleration/braking) grip you get.

Reply to
Nom

Wghich I agree with, and have never said otherwise - But I never once said you should always run wider tyres at the same pressures as normal/ narrow ones - Which seems to be your point against me...

I'm sure also that softer rubber will deform more for a given pressure too, so if you use the argument for softer rubber, then I'd expect an increase in longtitudinal contact too... Splitting hairs there though ;)

Nice to see you snipped out the bit I included about going up from 145 to

165 10s on a Mini should be done with a drop in pressure too.... In fact, I'm sure I remember the general advice about wider tyres was to lower the pressure over standard ones too, but I could be wrong on that. I do know the best thing in real world situations if altering specs is to follow safety guidlines, but adjust things to suit your driving. I run my tyres slightly harder than spec, as I prefer a more predictable, but not quite skittish, car, to one that grips grips grips, lets go. It also noticeably reduces tyre deformation on acceleration/ braking, giving a slightly more responsive feel all round, on my car, in my opinion. It's all down to preference though :)

Rambling now, but I suppose alot of wider tyres still run high pressures to make the car feel more responsive, and to decrease power sapping friction with the road to keep the mpg up. And for every day driving, ultimate grip shouldn't really be an issue anyway :)

Reply to
Stuffed

Er

"If something is physically wider, it will physically have more area in contact. The fact it is softer is no bad thing, but it doesn't detract from the fact that a 225 is alot wider than a 135 tyre, and therefore has alot more rubber on the road"

It will NOT have more area in contact, and will NOT have more rubber on the road, for the reasons above !

But you SHOULD always run wider tyres at the same pressures. Running non-standard pressures, is a bad idea !

If you're going to run them at a lower pressure, then why bother with wider tyres ? You could get the same amount of extra grip by simply running your normal tyres at the same lower pressure !

Yep.

Go back an read your original posts again, and then admit defeat.

Yep. The drop in pressure is what increases the contact-patch, and hence overall grip. The wider tyres, simply sacrifice some longitudinal grip from some more lateral grip.

It's the opposite.

If you're running wider tyres, they're lower profile, and on usually on bigger rims. You have to run them at a HIGHER pressure, because there's less deformation space - otherwise your rims will contact the road over a severe bump - and this is a-bad-thing.

Yep. It's almost always good practice to run your tyres about 2psi harder than the manufacturer says - you improve just about everything, at the expense of a teeny amount of grip. Stock pressures are always low, because they need to cope with stupid things like emergency stops on very uneven surfaces, etc. - not something you do in an everyday situations.

Yep. I'm running wider tyres, and I run em a couple of psi over spec.

Agreed.

Reply to
Nom

Do I have to state the bleedign obvious every time then?? :)

How does "If something is wider for a given length, it will have more area in contact" sound then? You are assuming one tyre comes off, another goes on, and the only thing changed is the width. Which to me is as stupid as taking one set of springs off, putting some lower/ harder or whatever ones on, and not bothering to check or adjust the camber...

Each change of specification has an impact on something, that should always be considered. So to me, changing the width of rubber should be done along with optimising the settings of the tyre, and quite often looking at how wider rims might affect other areas of the suspension. That can quite easily include changing the pressures...

Different tyre = Different characteristics = Optimal pressures for use can differ from standard spec for a completely different tyre!

Unless you're going to suggest a Goodyear 205/60/14 is identical in every way but width to a Courier 155/13, for example?

Sidewall flex, tread movement, greater lateral loading without over compromising longtitudinal grip... Many reasons. Although personally I'm not one of the Kev brigade, and am quite happily running 155s on my Triumphs, and 145s on my Mini, as with the amount of power available and lack of sunny weather most of the time in this country, there's plenty of better things I can buy for the cars than some flash wheels. Most likely going to go 195/14 of some profile or other on one of the cars eventually, but that'll do me fine. No point forking out for the mpg hit when I'm mainly stuck in town traffic...

I admit I made a sweeping statement, which is not 100% accurate depending on why and how wider than standard tyres are used and fitted. My basic logic that more rubber is more rubber isn't flawed, but I agree that depending on how you set up that extra rubber you can stand to have no more rubber for more rubber.

People that stick big exhausts on should also adjust fuelling and timing to suit, but if I'd said go for a free flow exhaust as it'll free power, would you still have shot me down for that if I hadn't qualified _why_?

And so, in effect? Oh, yep, I was right ;-p

Never having run rubber bands, I wouldn't know! But I see what you're saying... Seems a bit pointless then, if you've got to sacrifice grip to suit the road conditions, then why bother in the first place?

Then again, I ask myself that every time I see a clapped out shopping trolley with Wankfords alloys on it rattle past me...

You just said never to run non standard pressures! ;)

Glad you agree we agree on something at long last...

Reply to
Stuffed

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