Rolling Road??

[tasng4]

Does anyone know the French for 'Rolling Road'? In case you don't know it's a device upon which you put your car and it measures the power it produces. It can also be used to setup the carbs, ignition etc.

I have a slightly tuned MGB-GT which I would like to get properly set up.

Also if anyone knows where I might find one, preferably on 26 - Drome or 05 Haute Alpe that'd be great.

[Sunday Driver]

The French call them 'dynos'.  Try someone like Valence Tuning (04 75 83 08 30) for a recommendation.

 

[AnOther]

Believe me, unless 'slightly tuned' is a gross under statement you do not need a rolling road to set up an MGB !

What exactly have you done to it ?

[tasng4]

Thanks to both:

Sd: I've E_Mailed Valance Tuning to ask if they know of a rolling Road.

Another: Ordinarily I wouldn't need a rolling road but this car's set up seems elusive. It has K&N filters, Sports exhaust & manifold, mild road cam and skimmed head & block. Cirrently I have AAB needles fitted instead of the std AAU ones. The 'problem' is that the car, whilst better with the richer needles, still lacks the amount of oomph I would expect it to have even with 98 octane fuel.

Currently 0-60 time is about 17 seconds and I don't do enough miles in it to continually richen the carbs until I find the sweet spot.

Any suggestions?

[Anton Redman II]

For what it is worth I used to use Mitcham Motors to set up my MG 1300 which would eat Escorts on the Britvic. There is something odd about going past a Mexico with a van rear axle while you worry about the MG pulling 6350 in top

[AnOther]

Pretty much the same as mine then. I have never even thought to measure my 0-60 time so don't have a clue what it is other than it is what it is !!!

I don't know what you are expecting from your mods but cutting through the hype I reckon you'd be lucky to get much more than about 10 or perhaps 15bhp which is not really enough to snap your head back and say 'wow'. If you've gone beyond a 270 cam you'll almost certainly have problems getting it to tick over decently.

There are mixed schools of thought on needles and although I experimented with AAA's (never tried AAB) I went back to the standard AAU which is how it's been for the last 20/200,000 miles or so. It can't be far out as it returns 36mpg on a decent motorway run.

TBH the K&N's don't actually flow that much more than the standard paper filters so don't really need the richer needles. Their main advantage is they partially overcome the disruptive problems of a siamesed inlet manifold, and of course their longevity, but on their own they are unlikely to be worth more than about 3bhp. To properly set up SU's on a rolling road you need someone who is both intimately familiar with the type and knows how to actully shave the needle profiles to optimise the mixture throughout the rev range otherwise all you will get is an optimised full throttle. I doubt there are many of them in France !

Also it goes without saying that the carbs need to be in good nick with no air leaks around the spindles and have the proper and matched piston springs and dampers, it's not unknown to find them mixed. The little piston on the end of the plunger is actually an accelerator enrichment device which allows the pistons to rise undamped for a short distance so it's important everything is equal between the pair.

To get the mixture right you need to be starting off rich and weakening not the other way round. Assuming you've got the butterfly's balanced and the jets flush with the bridge in the carb the starting point is 2 full turns down on the jets, it's the same for standard HS4's or the later HIF4's - which BTW are far better carbs - and then weaken off 1/4 turn at a time. The engine needs to be throughly warmed up and you'll know when you've passed the sweet spot as the tickover will get lumpy so you then richen it up 1/8th of a turn or so.

PS: If you don't do the miles to get it setup why have you bothered tweaking it in the first place [Www]

[Théière]

[quote user="Anton Redman II"]For what it is worth I used to use Mitcham Motors to set up my MG 1300 which would eat Escorts on the Britvic. There is something odd about going past a Mexico with a van rear axle while you worry about the MG pulling 6350 in top[/quote]

Just a tyre and wheel shop these days Anton [:(]

Tasng4 I have an old diesel van which is faster 0-60 than your MG, it can carry a lot more too and doesn't have 24 bolts to hold the rad in [:P] for sale if your'e interested [;-)]

[just john]

[quote user="tasng4"]   Any suggestions?[/quote]

Yes, there is no replacement for cubic displacement, hence the MGV8; but engines (and suspension) have moved on and since fitting a Hoyle suspension kit  .hoyle-engineering.co.uk/ to my MGB it handles and corners so much better, so I'd have no hesitation in following his route to get that kick in the back, fitting to his MGA the Honda S2000 engine/box, they're cheap enough now, (they don't just bolt in and go though)[;-)], usual disclaimers

 amazon. ultimate+mg+performance+dvd

[Mr Wiggy]

It’s no good doing half a job by putting all these bolt on go faster goodies with skimmed head, then doing nothing about both inlet and exhaust valves and ports, polished and bigger ports & valves, the next step would then be a bigger carb for the new larger manifold.

Many years ago a friend of mine change the cylinder head on his Morris 1100 for a stage 2 tuned head, the kit included a skimmed head which raised the compression ratio to 9-1, bigger and polished ports and valves, bigger manifold plus carb and exhaust, all this plus Boyer electronic ignition. It went like the proverbial lump of whatsit off a shovel.

All you really need for the ignition timing is a strobe light, or even just a test bulb for static timing, you can also get a carb tuning kit too.

I certainly wouldn’t waste money on a rolling road.

[woolybanana]

Ohhh, I love it when you chaps talk gibber! Are you talking about the noisy, hot bit under the bonnet?

[just john]

probably more to do with the hot release of endorphins during excitement . . .
remember 'get your kicks on route 66', or get your kicks above the waist line[:P]

[tasng4]

[quote user="Mr Wiggy"]It’s no good doing half a job by putting all these bolt on go faster goodies with skimmed head, then doing nothing about both inlet and exhaust valves and ports, polished and bigger ports & valves, the next step would then be a bigger carb for the new larger manifold.

.[/quote]

ou're absolutly right, the original plan was to, possibly, supercharge the car and with this in mind I wanted it STRONG! It has bigger big end bearings as well. Anyway I did have 1.75 HS6 carbs on it but it was over carbed so I reverted back to std with richer needles and it is better. I think I'll do as suggested above and start the tuning process from being rich.

The ignition is spot on, new dizzy, leads etc. so I'm happy there.

At the moment I'm busy with my other MGB trying to get it ready for importing & CT.

Anyway have you seen the price of stage 2 heads........dunno exactly but it's loads.

[AnOther]

[quote user="tasng4"]the original plan was to, possibly, supercharge the car[/quote]I think you are quite possibly mad !

If you want that sort of grunt get a V8 or go N2O.

[crossy67]

It's been many years since I touched anything with carbs, let alone SU's. Stromberg or Zenith so ignore what I say if you want.  I am much more into tuning turbo motors now, much easier and better rewards for your efforts. 

Are you 100% your ignition timing is right and  that your vacuum advance is working as it should?  Your symptoms sound much more ignition related to me.  You will loose much more power by over fueling, for more power you want it leaner (at least with a turbo any way).  You could try advancing your timing until you here the engine pinking under load then retard it a couple of degrees, this is how it's done on a rolling road.

Hows about putting standard carbs back on or even better a set of motorbike carbs, they are the real performance carbs. 

[tasng4]

Thanks to everyone who offered advice and suggestions, my car is now running well. It's just like a new car, as far as who's suggestions were right - it was everyone. I've made small changes to the ignition timing, Carbs needles, mixture settings, changed the exhaust/inlet gasket and tapets. OVerall there were lots of tiny problems.

If I get the chance I will still go to a rolling road (maybe when next in the UK in the MG) as I'd like to get it spot on but in the mean time changes will be restricted to checking the plug colour every so often.

Regards and thanks.

[AnOther]

Good for you but I'm still unconvinced of the value of a rolling road session. To get it 'spot on' in the sense of driveability and real world performance, where mid range power and torque are worth 10x more than 0-60 times and sheer top end which you'll never use, it's probably just as easy to drive it more and make small adjustments yourself. You've only 2 things to adjust, timing and mixture, and in the increments we're talking about neither will really be dependant on the other.

When you can get 36mpg out of it 2 up on a 110kph motorway run you'll know you've got it somewhere near right [:D] [:D] [:D]

[Anton Redman II]

Have you ever had anything set up on a rolling road ?

Never seen anything with an A series which has not had a significant improvement in torque. Anything with an SU carburetor can have both the size and shape of the needle changed. Changing the taper does make a difference accross the flow range and which does make a difference.

[AnOther]

I don't disagree and actually yes, I've had my own B on one but only because I have a pal in UK with a garage with one and TBH it was more out of curiosity than any desire to wring the last 1/4hp out of it and as much to prove to myself that I'd got it set up optimally as anything else, which I had.

As it stands the B engine is not really what you'd call a high perfomer and after 25 years experience with them I still maintain that for all round driveability on public roads a properly set up standard car is pretty hard to improve on and therefore a RR session is a waste of both time and money.

If we were talking about seriously modified engines I'd take a different view but in this intance we're not.

[Théière]

[quote user="AnOther"]

As it stands the B engine is not really what you'd call a high perfomer [/quote]

[:D][:D][:D]

 

[just john]

High performer against what for example, any other 60 year old engines running round in such numbers?[Www]

[Théière]

Bhp/litre

One advantage of BMC leyland not being around is we have got rid of this series of engines and moved forward otherwise they still be trying to use them in some crap vehicle was last one the Ital?

[tasng4]

Oh I wish I'd never started this. Overall I agree about RR's, however when in the UK I was 'flashed; and told I was doing 35 in a 30 I disputed this & so went to a rolling road to verify the speedo. Part of the 'service' was a BHP readout - I was getting 60BHP out of my 'very slightly' tuned 'B'. So as well as setting it up I wanted to get everything sorted at the same time. Of course we have to remember this car had a 0-60 time of 12 seconds, ages now but in the day 20-25 secs was normal. I'd just like to get performance as per 'new'.

Re: Ital - the only good thing about this car is that I can scrounge parts for my 'B'.

Does anyone know what BHP would be reasonable for a 36 year old car running on modern petrol might be?

[Théière]

[quote user="tasng4"] Re: Ital - the only good thing about this car is that I can scrounge parts for my 'B'. [/quote]

Just have to change the flywheel bearing spigot bush I seem to remember one very cold night in Caterham, shiver [:)]

[AnOther]

Yes, you don't do what the donut who put a Marina engine in a B roadster I bought did, angle grind off the end of the gearbox input shaft !!!

A standard B put's out around 97BHP @ 5400rpm but with the transmission losses you can reckon on something in the high 60's or low 70's at the wheels and in good fettle no reason to expect it to be doing any more or any less even 36 years on.