March 22nd 2017 | 15 minute read

DYNO DAZE – Dynomometer Testing

Dynamometers are a passion of mine and in this write-up I have a concern that the proper tuning of classic cars is coming under unreasonable pressure, not because the expertise is missing but because the modern world of ‘easy everything’ is hurting the professionals in this field.  You will also note that I will have a swipe at the F1 guys whenever the opportunity presents itself, because they need it….so whilst talking about BHP and stuff in this article…. I give them a swat. The reason for this is simple, my primary interest on F1’s is the engine.  It’s the driving force in the whole thing, It’s the core…but we know next to nothing about outputs……There will be a dedicated article on this soon.

Over the last century, the engine dynamometer has, without doubt been the most productivetool in the armoury of equipment necessary in the development of the IC engine. It has been used brilliantly by most, abused by a few, misunderstood by many * and incredibly, going by the secretive behaviour of the modern F1 gang   … we, the great unwashed, are now not entitled to know what Dyno’s are saying.  *The perennial argument on Torque vs Horsepower

C’mon  guys, we grew up with horsepower as the founding statement in the business of tuning engines. The ‘magic number’ milestones defined our times. 100 Bhp/litre was the magic number of the early 60’s.   In 1967 an eye opening 220 Bhp from a 1600 FVA based on a production Ford soon got our attention. In that same year so did 400+Bhp from the V8 version of that brilliant design. Moving into the turbo era, we were staggered by the 1400bhp from BMW F1 qualifying engines built from stock 4 cyl 2002 BM engine blocks.

From the early 60’s we were treated to equally mystic numbers on standard production cars ….. 105 Bhp from 1300 Renault Gordinis, 110 Bhp Cortinas, 300 Bhp Z28’s and 400 Bhp Hemis. These were defining numbers providing all petrolheads with an understanding of the pecking order of things. Without knowing the Horsepower…what exactly is the point?

We’ll get back to this later…..

Modern times, however, have all but eroded the anticipation and mystery involved in the quest for Horsepower. Wind-up the boost (or fit a larger hi tech turbo), chuck in a bit of NOS, turn a knob, hit the keyboard and horsepower arrives on demand. Nothing too mysterious in that anymore is there?

I come from an era where God’s natural gift of ambient air pressure provided the basics for filling a cylinder with air. The challenge was to make horsepower not only with that as the baseline but using cantankerous old production engines to get to heady power figures and crazy rpm. This was a real adventure, so when one has the privilege today of working with Dyno Maestros like Maurice Rosenberg of Autorosen in Jo’burg, the mystery and excitement of that era returns. Dynamometer tuning specialising in classics is under pressure and not only is the real expertise waning but the parts needed to remain period correct are also becoming harder to find. The folk involved are the conductors of the Classic Engine Orchestra. The music they produce equates to motorised Mozart and every successful event is a unique musical script.  Maurice has the uncanny ability to provide the score….. but increasingly today people like him come face to face with that modern mindset of easy horsepower.  That single issue is, in my opinion, beginning to undermine the value of the people like Maurice in this business.

Having run my own tuning operation in the late 90’s, I know just how difficult it is to satisfy customers even when the job is done properly ….but…..with the number of “know it all’ types increasing in these times it is becoming even more difficult. With some experience, I soon learnt how to avoid smartasses in order to keep the ship on an even keel but the problem today is growing. Google seemingly knows everything and the knock-on is that those types now really know absolutely everything…… in addition to the fact their uncle/brother/cousin or equally smart friend knows even more.

Potential users of dynamometer facilities need to be educated. Taking a car to a Dyno brings with it some critical responsibilities, that is, if you want good results. Nothing is more frustrating to seasoned Dyno man than a poorly prepared engine/car. Properly set-up engines are responsive on a Dyno….. That is, responsive to timing adjustments (cam or ignition), fuel mixture and…..they don’t overheat as a result of poorly sorted cooling systems.

So to those who want to achieve results from your hard earned $, here is Paul’s very basic check list  before you get to the rollers (there’s a lot more if we get into detail of how to build an engine to make it easy to tune) :

We’re assuming here that we are talking about Carburettored Classic Cars

 REMEMBER …….THE OBJECTIVE OF A DYNAMOMETER SESSION IS TO TUNE AN ALREADY GOOD RUNNING ENGINE

NOT

TO SORT A MISFIRING, SPLUTTERING, OVERHEATING PILE OF JUNK AND RELY ON THE DYNO SESSION TO FIX THE PROBLEM.   

  1. Don’t build an engine from Google, your Uncle, Brother, Cousin or clever friend’s advice…. take responsibility in using all input and check with those who really do know. You will not get everything 100% but, taking personal responsibility for the package you eventually take to the rollers will set you on the right path.
  2. Make sure that Fuel pressure is to a level accepted by your Dyno man. More time is wasted on this single issue than any other. Fitting an adjustable fuel pressure regulator because it worked on your buddie’s Cortina fitted with the same engine…No.

Fit a fuel return line in all cases and get to the rollers with 4-5 lbs of fuel pressure off an adequate fuel line size…..and the ability to change fuel pressure if required. Don’t forget time is money, if your dyno man has to rush around fixing incidentals it wastes good roller time.

  1. Ignition system. Do a little research and find out what works in terms of the hardware and basic ignition curves. Talk to your Dyno man beforehand to get this done before dyno day and…. Run the engine through the rev range on the road at full and part throttle, to ensure that it is at least ‘clean’ with no obvious coughing and spluttering. Again…sorting this before saves time and your $.

If there is a problem (misfire) that needs sorting, make sure your Dyno man knows the  condition before Dyno day. He needs to decide on the best way to sort the issue before the rubber meets the rollers.  I’m not going to be kind here….don’t be that guy  who ‘slips-in’ a problem engine and claims that “it was good yesterday” expecting it all to be handled under the quoted tuning cost…..not fair

  1. Check full throttle and clean accelerator travel
  1. Talk to your Dyno man on basic Carburettor settings. Google and friends telling you to use the biggest carbs with massive choke tubes will not work. If you are experienced and know what worked before…great… if not, listen to Mr Dyno, especially if this happens to be Maurice. The objective is to get as close to what will work before you start. Here is a bit of reverse psychology….anything fitted as recommended by your dyno guy immediately puts a little pressure on him to find the solution if it does not hit the jackpot on the early runs. Don’t try to be smart, try to learn. Believe me I’ve been working on Dynos all of my life and every single time I am involved, directly or indirectly, I learn.
  1. Cooling systems. Make sure you have adequate cooling for Dyno work. Where necessary, remove radiator grills and install temporary cardboard ducting using duct tape/foam fillers to channel air to the radiator. Remember, keeping the engine cool is a prerequisite for repeatable results.
  1. Cool air inlet to the carburettors. Do not allow the engine to pull air randomly from the engine compartment. Make sure the inlet air is ducted from the external source representative of a bonnet/hood closed condition. Get cool air to the Carbs.
  1. Smooth transition. So many cars with multiple carbs get to the Dyno with air leaks, splutters and coughs in the off idle mode. I do not understand this, as that portion of the tuning envelope has nothing to do with Dyno work and is easily set up under normal driving conditions. Talk to your dyno man, fix air leaks and sort idle jets to allow smooth transition off idle…it simply makes the process easier to manage on the day.

I applied this check list tuning the Magic 1088 Opel with Maurice a few months ago and the result was stellar. Watching the wizard at work was just one of those special occasions and gave us time to learn a few things that day that neither of us had anticipated. The point? The engine was responsive to adjustments and allowed the man to use his expertise to arrive at a remarkable result.

Thank you Mr Rosenberg.

Read the blog story “The Magic 1088”

PDM Clark Dyno Daze

Prep for a good Dyno Run on the 1088

  1. Radiator grill removed
  2. Sponge seal around rad
  3. Aux Rad (Cyl Head Cooler)
  4. Cold Air Duct *

Be careful with this type of ducting. A/C housing and duct must be vented to prevent standing waves in inlet tract. DON’T force it….Just get the cold air to the carburettor …the engine will know what to do with it.

About those F1’s ……….The 2017 F1 season is about to start and we hear that Ferrari is on the pace in initial testing. Now if we knew the real Bhp of the various contenders the same way we have known this since pa fell off the bus, it would make it interesting….but I guess we’ll have to wait for Melbourne for another year of estimating the horsepower gains and debating these amongst ourselves until November…..while the modern dynamometers read-outs are kept in a safe…..funny how the motor in motorsport is being minimised…..I guess we are being prepared for the ultimate electrocution.

Sorry to go on about this but here is what I would find interesting, imagine all F1 manufacturers divulging real Bhp figures…. that would be progress indeed… Better still……forced to give all figures…. Cruise power (the sort Hamilton uses when way out in front)……Race power (first five laps)…..and Banzai overtake mode (sadly Honda not able to use this mode at the moment)….. and of course Cupboard mode (this is unique to Mercedes who keep stuff from their prodigious R&D operation under wraps in case anyone gets too close too often)….. lastly, electrical power.

You see, the world of tech around engines today is so interesting that it would be a hundred times more valuable to fans than knowing a DFV produced 407 Bhp in 1967… As a matter of fact, I heard on the radio again a few days ago that we have more information instantly available on our smart devices and at our immediate disposal today, than all mankind had assimilated up to a few years ago……but….. we again don’t know what horsepower the Ferrari is making in comparison to Mercedes this year…… Really?

I don’t often become unreasonable but I am absolutely unmoving on this issue. For me, knowing the power figures in F1 is a prerequisite to understanding what is happening on track…otherwise it’s just a crapshoot and conjecture ……

By | 2017-11-24T10:11:35+00:00 March 22nd, 2017|Categories: A Different Corner|Tags: , , , |1 Comment

About the Author:

I have been in the motor industry all my life and despite spending 20 odd years with Datsun/Nissan, remain a GM man at heart.

One Comment

  1. Bruce Meaker March 29, 2017 at 8:43 pm - Reply

    Would this be the complete power unit output or just the combustion engine?

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