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MG Midget and Sprite Technical - Performance Leads Test (at last)

Hi All

Nigel kindly arranged a set of MGB plug leads for me to try out. In the end I thought I would try them on a 1000cc A series grasstrack racer as any power increases are most welcome in this tight class. Here is a copy of the email I posted to Performance plug Leads and a copy of the power graph.

www.performanceleads.co.uk

Thanks for setting it up Nigel

Peter

Hiya

You kindly supplied me with some MGB plug leads to power test. I have been waiting for a suitable car and decided to test them on a Mini 1000 grasstrack race car. After tuning the car we fitted your leads. The bhp at the wheels went from 43.8 to 44.5 and the average torque went from 55.8 to 57.5 lbsft. I attach a picture of the power graphs for you the, blue line is with your leads ( dotted line is torque and solid line is bhp) as can easily be seen your leads were better everywhere. Most impressive.

Peter



Peter Burgess Tuning

Interesting... fit 2 sets for 2x the gain ;)

A
Anthony Cutler

Hi Anthony

We were quite surprised to see a gain over good standard items. When Nigel said he thought the midget seemed sharper after fitting the leads I thought he was maybe convincing himself, remember taking the baffles out of moped exhausts and going slower yet it seemed faster?
If the originals were getting tired then a gain should be felt.
To be honest I have always said if the thing is sparking it must be ok....how we live and learn, and learn and learn :)

Peter
Peter Burgess Tuning

Indeed - what's really needed is some way of measuring the energy in the spark under bench conditions, and trying all number of things (in a controlled manner)to optimise, then see how that translates into torque on a dyno... so leads, coil, points, condensor, rotor arm could all play their part.

Sadly - this sort of thing takes time, and also assumes consistency in the brands supplied.

BTW - when at VSCC new year's day meeting a couple of years back, someone demo'd their De Dion Bouton ignition system to me, taking the lead off the plug (yes, just the one cylinder) and turning on the ignition; when the points closed, the spark was provided by a trembler coil... so much energy, you could nearly weld with it - the (continuous) spark being around about 1/3 of an inch. A measurable amount of energy even without the vapour being added... (probably not good for TV, mobile phone, GPS, ... in the immediate vicinity!).

How would that do in an ASeries? All you'd need to add would be the trembler...

A
Anthony Cutler

So .... What is REALLY happening here to get this increase in performance

I know that sounds like an odd statement, but if this is true then would you get a bigger bang exploding dynomite with better wiring or a brighter light bulb with agian better wiring

Granted i understand a real crappy perforrmance with low end wiring, but id think once you got to a certian standard..there is a point where you cant get any extra advantages...which is where id think must leads are consiard normal... Due manily to competeion from B2B

On the test did you di a lead to lead test or a before and after performance test of the engine...

Sorry i dont mean to be argumentive just curious more then anything

Prop
Prop and the Blackhole Midget

Hi Peter,

thanks for posting

a small increase but an increase never the less

I was, as you've put, very happy with the performanceleads not just the actual performance but the build and quality of the leads

they make leads for others to put their name on (some more expensive names I suspect) and other cables so they know what they're doing - http://www.performanceleads.co.uk/

they feel like they will continue to perform well and last for a good while

nice to have some paper and technological back up to what I felt I knew and experienced

the previous leads were 7mm silicone, less than 3 years old and unfortunately not a huge mileage but reasonable on them

the small increae shown by you does of course mean my other improvements must have added even more to my increased rolling road figures for my car, with more Welsh beer to be consumed this coming week we need all the power to weight we can get from my Midget :)

note in photo below no oil leaking (at the time, dry rust) and the sand blown in from the wind


Nigel Atkins

Well, 1 to 3% depending on how you figure - races are won or lost on far less. I suspect this may not be a universal result, but it bears further lookee. Would be interesting to know the cable construction. Don't have time to look it up now.

Prop-
"So .... What is REALLY happening here to get this increase in performance

I know that sounds like an odd statement, but if this is true then would you get a bigger bang exploding dynomite with better wiring or a brighter light bulb with agian better wiring"

Yes!

Honda did a bunch of testing on MC GP engines, and found that engine power output increased directly with spark energy, but they had mains power. They kept increasing it until the electricity used exceeded the engine output. At that point it is a lightning-plasma engine, not an IC engine.

I have built vibrator coils, and they are scary. The one on my little antique hit and miss model will throw an arc about 1" easily, on a 6V battery. Made it out of a Briggs mower coil and points/cond, added some fabrication. Once you understand how they work, you can use them to start recalcitrant engines which will not fire any other way.

FRM
FR Millmore

Well this certianly opens up some possiabilities for me

I had always thought the ignition system took what it needed to run and not much more... Sort of like a cap, but you could starve an ignition with worn or poor wires

I had been considering a MSD system... Multi spark discharge (al 6) ...

if you can get one big spark VS. lots of smaller sparks...what are the Pros and Cons

Prop

Prop and the Blackhole Midget

I wonder if this increase is repeatable.Even the same engine with no changes will show some variance from one pull to another. Small changes in engine temperature,diff temperature even tyre temperatures will affect repeatability, and the odd percentage gain or loss is to be expected. I think to verify the increase you'd need to put the old leads back on, do a second run, followed by a further run with the performance leads.If this agreed with the first test then the increase was repeatable.
F Pollock

Our dyno is very repeatable for accuracy of results.

We had spent a long while tuning the engine so we were happy with it.

The figures are auto corrected for temp pressure and humidity.

This car is not pulling enough to lose much from tyre heat. We also do coastdown tests regularly to ensure the losses have not changed. We felt the engine was ideal for trying the leads as it is low powered and very stable.

remember we are pulling inertia runs so the equipment will not vary the readings as with using a pau for testing bhp.

If I wasnt happy with the results I wouldnt have published them, I dont play those games, I don't need to. The results stand.

Peter
Peter Burgess Tuning

Wait a minute now...

Peter are you saying you didnt throw the car on a big barrel of water and go for a spin with an 15 dollar timming light and an old spare rpm gauge out of a junk yard. To come up with those results


Well.... Now that changes everything...hahaha

I no doublt trust your methods and results... To be honest, i had firvoten it was you that posted, this thread... But i guess we are just wrapping our head around the end results, and trying to eliminate any other culpretes that would cause a false reading...


When i came to jesus, it wasnt blindly...anf accepting as much as a 3 % gain from spark plug wires alone isnt by blind trust ither... But that dosnt mean i have any less respect for your meathods and thoughts then i did 10 minutes ago.

Prop
Prop and the Blackhole Midget

Hi Prop

As I said, I have been dyno tuning for around 25 years and I always told folk nothing to be gained from plug leads if originals intact and functioning. It was time to eat humble pie when we tested the leads. The older I get the less I really know.

The Mini has to run on points for its class. This may have been a factor as the spark is less precise than electronic or maybe electronic would have shown better improvement?

As an aside, the lead manufacturer supplied leads foc for testing, I suppose they must have had some confidence to do so?

As a further aside I couldnt get the owner to swap the leads back so they are now on permanent test! These Mini grasstrackers are glued to the power plots and you wouldn't be able to slip anything past em.

We mess about with 1 thou changes in tappets to try and ring the most out of these engines, serious stuff.

Peter
Peter Burgess Tuning

Hi Guys
Thw answer to increasing spark is probably in two parts:
1 the magic leads allow more electrons to flow, I suspect, by optimizing the resistance, inductance and capacitive effects of the high voltages involved. This is not a simple flow of electrons at 12 volts.

2 So called "High energy" systems, which work by optimizing the points dwell, amongst other things, allowing more current from the ignition wiring to flow through the coil

I have built kits available here in OZ and I know they work. Below is a link to Jaycar who can sell you one.

http://jaycar.com.au/productView.asp?ID=KC5442&form=CAT2&SUBCATID=965#11

My final point (hahahaha)is to provide more current to the standard points and coil by using a relay and replacing the ballast wire in the loom with an external ballast resistor which can be optimized to give gtreater current to the coil but not too much so that it runs hot or fails. Aftermarket sports coils work by being designed to run at lower voltages, but they are more robustly designed to withstand this. i.e. they can run hotter without failing
Hope this helps
R W Bowers

Hi Peter very interesting results performance leads list 3 types of cable, ferroflex, maglite, and copper core which type did you test? I wonder which would provide best results.

Gary
G.J. Puxty

Hi Gary

I guess they were the Ferroflex variety.

http://www.performanceleads.co.uk/ShowDetails.asp?id=610&code=FLA114

Peter
Peter Burgess Tuning

I have a set of the Ferroflex (local supplier!) in my race car and very pleased with them.
John Collinson

Ok so thats the leads, but what about the ignition, Lumenition, Ignitor or the red chinese trigger things or just plain and simple points Is there much difference between them?
Mark Turner

The Mini was on crappy points as that is the class specs!

Of interest we are hearing about/seeing one or three of the acuspark systems "shuffling off this mortal coil" after a year or so anybody else?

Peter
Peter Burgess Tuning

Update;

their web site no longer has a direct 'click 'n' buy' but you can still buy direct by phoning which also offers colour options

I enquired about a set for my mate's Rover V8 engined car (so 9 leads) and I thought the price was very reasonable considering it includes P&P too

(from email reply to me)
The total price for the FLA403 lead set is £58.80 including VAT and UK delivery. We could make and despatch in two days. Any colour preference? We have light blue (as per the website), dark blue, red, black, grey, yellow, orange and white.
Nigel Atkins

Thats a very comparable price to some of the big race names for good quality leads..exp. "accuspark"

Prop
Prop and the Blackhole Midget

Ant wrote

"Indeed - what's really needed is some way of measuring the energy in the spark under bench conditions,"

I could do this at work, couple of different types of lead would be needed, can measure spark energy.


" (probably not good for TV, mobile phone, GPS, ... in the immediate vicinity!)"

it really isn't good at all, hence the work interest.

That price is about half what I paid for a magnecore set, claiming minimal crossfire on the V8. They do work well though, but a bit of a kick in the wallet.
Rob Armstrong

another good thing for us over here is that it's a English/British/UK manufacturing company

they also retail what looks like a high spec Maglite but you'd have to check the sheet as I'm not technical - http://www.performanceleads.co.uk/MagliteDataSheet.pdf

another good thing is that unlike some others they don't just do one set fits all, the lead sets for RV8 engined cars vary with car

for Midget 1500 owners the leads are at a proper length instead far too long

plus you can ring them if you have variations or want different lengths or terminals (or even colours)

they seem to deal in wires and leads -
"Fastlane is an experienced first tier supplier of wiring looms to the automotive, railway and industrial sectors. Our products range from small link leads consisting of just two wires to complex harnesses needing many hundreds of wires with multiple connection systems and terminations."
Nigel Atkins

Rob,
no doubt you've got your leads separated by combs rather than tie-wrapped together but there's also a bit about keeping leads for 3, 5 and 7 separate, as detailed here from Paul Hunt's mgb-stuff web site (and illustration link below) -
"The other thing to be aware of on the V8 is that cylinders 5 and 7 are next to each other in the firing sequence as well as being next to each other on the engine, and at the back so the leads are quite long and run parallel to each other. The factory seems concerned that the firing of 5 could induce enough voltage into lead 7 to initiate premature firing of that cylinder, so show the two leads 5 (red) and 7 (blue) being separated in the combs by lead 3 (green), as shown here."
http://www.mgb-stuff.org.uk/plugwires.htm#2

and there often seems confusion in the descriptions of which is the even numbered bank and which is the odd
Nigel Atkins

yep, all separated by combs and far apart as possible, one of the other problems with the V8 is the angle between the leads on the cap is small as there's 8 in there.

crossfirng was a real issue with the cheap leads I had. Not sure I like the alignment of those B leads in the picture mind.
Rob Armstrong

in the illustration it sticks to right angle connectors for the all the offside bank and straight for all nearside bank whereas I'd tried to have less close crossing of leads by perhaps not sticking with that arrangement

I think with the BGT V8 it said that bonnet clearance can be an issue but I can't remember that being so on the P6 but sometimes you also have to allow for the coil lead depending on where the coil is fitted in that particular car

I can never remember getting a very tidy fit on the RV8 engined cars with aftermarket leads no matter how you positioned the leads one or two were a bit tight

I made up my own leads where you cut and terminate them yourself and even that is awkward doing one lead at a time and the using the old ones as trial positions and layout to see the least path of congestion, I found I didn't use all the spaces on the fixed combs
Nigel Atkins

This thread was discussed between 05/09/2012 and 11/02/2014

MG Midget and Sprite Technical index

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