Rolling Road advice

[chrisryder]

the only films you see are of the things that go wrong. they must only be a small proportion of all the tests that have ever been!

the mini place in napton (southam, wherever!), is it just a rolling road or does it act as a dyno aswell? do you get told how much power you may(or may not...) be kicking out?

i'd certainly be keen to give it a go. may just take the one car and see how impressed i am.

[Alec]

Hello Chris,

a rolling road is a dynamometer, no different really to an engine dynamometer. The difference is that the measure is at the wheels so the figure does include the transmission losses. As these losses are fairly well known a reasonable assessment of engine horsepower can be given.

Alec

[bmcecosse]

For Kevin (and others) my comment was where I would take my car IF I decided it needed rolling road tuning....... Others can take their car wherever they like! But on the Mini forums - ACD is VERY well respected - and some of the stories about others are well , lets just say 'not so good'. Some blatantly produce unlikely high figures - good for Pub Points!! But not much else.......... I have never seen ANY mal comments re ACDs work. Nor have I seen any mal comments re Mini/Metro place mentioned earlier - but then I haven't seen any good comments about them either!
I would just ask anyone going to a RR session to report back what gain is made - and by what means!
Having worked with rolling roads many moons ago on racing and rallying Minis - we were able to gain precisely nothing on either car over the set up that had been put in place already using road and track testing. The racing Mini appeared at first to show a power increase when the ignition timing 'map' was adjusted. Following week at the morning practice session the owner/driver reported the car to be almost undriveable - and his lap times were well down on previous. (His language was rather more colourful - but that was the gist of it......) We put the ignition back as before - and back to normal performance. He went on to win the Scottish Saloon Car Championship that year. So - just beware - the rolling road doesn't really simulate real life!

[Plin]

I find all this quite mind boggling but informative - but most of all I love your comments bmcecosse which come from your years of experience. Much like my favourite vet who would never mince her words if pet work was really not worth the money! Both are rare so we value your often common sense comments Roy!

[Alec]

Hello BMCE,

there's no doubt that (particularly modified) cars can be set up by road testing, after all that is how it was done pre 'rolling roads', however it is time consuming and, these days, finding a suitable road without too much traffic can be difficult. Without adding the factor of operator skill, rolling roads are a good tool to fine tune an engine.
Also there is nothing new in an apparent gain in power giving worse lap times. Alf Francis, in his book, Racing Mechanic' relates how he spent the winter working on (Sir) Stirlings Moss's car and made considerable gains in power. However the driver was not so pleased as he was slower than he had been, so driveability is another aspect?

Alec

[Longdog]

Hi my solution to a rolling road was to get a mappable distributor,Wide band Air/Fuel gauge and take the advice of A C Dodd on needle for equivalent engine spec. Needless to say his advice is spot on. The great advantage of doing this is that I have a permanent "rolling road" mixture read out which shows when I am wasting fuel and I can verify mixture in the real world, however the best part is not having to pay a lot of money to have somebody rev the T@£%$ out of the engine.

[bmcecosse]

Excellent! Yes - I would love a mappable ignition - but electronics and me don't seem to get on well.. You wouldn't care to share ACDs needle secret with us longdog....... ??

[Alec]

Hello Longdog,

how do you judge what settings to use for your distributor?

Alec

[Longdog]

I have a 123 ignition set to 30 degrees all in ( curve 7) dead easy to change via a switch underneath. The lambda element is a Stack unit which uses a Bosch oxygen sensor which is located south of the LCB. Engine is 1380, 266 cam HIF44 with stage 3 head and free flowing exhaust (rc 40 equiv by Maniflow).
A C Dodds for a similar set up prescribed a BBA needle with red spring. Fueling comes out at 0.86 lambda during driving with a tickover of 0.89 which eliminates plug fouling. Engine is very smooth and torquey so no need for rolling road. I don't know what BHP is, but Bob will wiz over most modern stuff so that will ding dang do for me. On searching Mini tuning bloggs it is possible to come accross a large variety of engine capacities, comp ratios and tuning goodies to give a good idea of needle selection as per ACD. He must have tried and documented so many combinations his advice will at least yield a good starting needle with worst scenario a little reduction on a drill press. settings for distributor are selected by trial and error ie, no pre igntion with the hottest advance curve. Hope this is of use, Andy. P.S. by my reckoning the Lambda gauge cost about the same as 2 rolling road sessions with unlimited tinker time.

[Alec]

Hello longdog,

"how do you judge what settings to use for your distributor? "

You still haven't answered that question? To me ignition is far harder to adjust (and easy to over adjust with electronic switching) than fuelling as it is difficult to tell what is right just by driving? I suppose that using a knock sensor could be one way but I've yet to see anyone mention using one?

Alec

[bmcecosse]

Thanks Longdog! The 123 is not really 'mappable' - it does have several built-in advance curves - but actually when you study them - they aren't that much different to each other. Truly mappable ignition (Megajolt) is available - and is said to allow use of long period cam with good low speed running. I wish I had the ability to build it!
The BBA is very very similar to the almost 'standard' choice of BDL as a starting point for upgraded large bore engines. It's just very slightly richer in the top half of the rev band.

[phurn]

as ive told you before bmc, its really not *that* hard ot fit! and the results speak for themselves. im prety sure if i can do a head gasket then you can fit a megajolt! id actually be very interested to se what difference it makes to an a series lump.

[Longdog]

Here we go again

[Longdog]

This forum always seems to end up degenerating and pooh-poohing ideas, and it is usually the same culprits who put their six pence worth in on products they neither own or have tested. I'm going to have my rant because I have way better things to do than play some sort of moronic game of mine's better than yours all the time.
I hoped things since my last post on here had changed, but no, still La meme chose.
Au revoir!

[Alec]

Hello Longdog,

you may not read this as you have said goodbye, but the idea of a forum is to discuss pros and cons and in the doing of which assist others. Why get upset when you see opinons differing from yours? There is a wealth of experience and knowledge here, but you also need a sense of perspective and understand why various opinions are put forward.

Alec

[phurn]

Tbh if you don't like the idea that someone might have an opinion better than yours then keep it to yourself. That way There's no problems.

[bmcecosse]

Ha! Was Ld having a go at me ?? I quite like the 123 dizzy and have often suggested it to folks in the past - but it isn't 'mappable' - it just offers a range of advance curves (actually straight lines) , and when the detail is investigated they really aren't all that different from each other.... And the price has risen dramatically - they used to be quite affordable. If there was a bolt-on megajolt kit at a fair price I would be interested. But any I have read about involve scavenging various parts from the scrappy - and then soldering into the PCB - something which I have had spectacular failure with in the past...... But the idea of being able to truly map the ignition advance does appeal - and it is well spoken of in Mini circles. At least Ld shared ACDs needle 'secret' with us.... In fact I believe that if an engine is rolling roaded in ACDs presence - he customises a needle to precisely suit THAT engine. This why it's possibly the only place I would bother with for rolling road tuning. I suspect the BBA needle suggestion from ACD is just a rather general guesstimate needle, as I said earlier - it's just slightly richer in the upper range than the 'standard' BDL needle.

[Alec]

Hello BMCE,

you probably know of Kas Kastener; he designed and built a 'mini lathe' to profile needles to his requirement. Quite a simple device really, he seemed to be a very practical engineer.

Alec

[bmcecosse]

Not heard of him Alec -but I believe ACD just puts the needle in an electric drill and spins the needle against wet/dry paper. Or for a single carb - it's perfectly ok to simply file a flat on one side of the needle to richen the mix where required. Not so easy though to make two identical needles that way for twin carb use.......

[Alec]

Hello BMCE,

he is a well known (predominately Triumph) tuner, he ran the American works racing TR's in the sixties and was very successful in extracing a lot of power from the four and six cylinder Triumph engines (More than they could over here).

Alec