Day On The Dyno

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Mercules

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Had a very interesting day today... my clothes and hair stink of exhasut fumes but I have learnt quite a bit about k-jetronic, adjusting it and found some excellent results.

dyno_02.png

After some warm-up and checking cruise mixtures, the furst dyno run saw 141 horsepower at the rear wheels with 845 lb. of torque and kicked out an enromous amount of smoke - just clearing its throat for what was to come!(please note this is a dyno measurement - not a comparison to factory specifications).

The mixtures were pretty much bang on stoich from idle to redline, which was quite dissapointing because I have been so unhappy with the fuel economy (24 L/100km) I was expecting to see an overly rich reading!!! A quick check of the ignition timing comfirmed the engine was set to factory specs!

dyno_03.png

To see if we could achieve a leaner mixture, better fuel economy and still make decent power, we adjusted the mixture slightly leaner... second run made 148 hp. We adjusted it some more... third run made 152 hp. This was getting a little weird - we were pulling fuel out but making more power with each adjustment and there was definately no pinging! A fourth adjustment made no difference so we thought we would try advancing the timing a little...

dyno_01.png

RED INDICATES FIRST RUN - BLUE INDICATES LAST RUN - SOLID LINE INDICATES POWER - DOTTED LINE INDICATES TORQUE

5 degrees advance resulted in the figure above of 157 hp and 931 lb. of torque. That equates to an 11.5% increase in power and a 10% increase in torque... not bad for a few adjustments.

On the road the engine feels very different - light throttle produces an irresistable surge and when full throttle is applied, you can really notice an improvement in response and acelleration.


THIS IS THE IMPORTANT PART THAT I WANT EVERYONE TO READ!!!
==================================================

When the air cleaner was refitted, we checked the power with another dyno run and found it LOST POWER but the mixtures became RICHER!!!!! This explains the precise reason why some of you may have noticed an improvement in engine performance after fitting a free-flowing induction or cold-air setup - your engine is actually running RICH and making less power to start with, so by improving the induction airflow, the mixture is LEANING OUT slightly - bringing it closer to an optimum ratio and making more power!!!

After having travelled almost 240,000km and never been opened, my engine is in average condition... a couple of the lifters are ticking and there is noticeable blow-by coming from the rocker breather pipes - so while new piston rings and some valve adjustment may be an expensive way of bringing this engine back to its former glory, there is a lot to be said for some tinkering with the fuel and timing.

If you are interested in a dyno tune to get the most from your k-jetted beast then call Pulse Racing on (02) 9543 5007. I am very glad I did :D

Cam
 
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Michel

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Very interesting to read.

So, the quick fix (beside a dyno tune) is to put a sports air cleaner (american V8 style) and that should improve airflow/fuel/performance?
 

BenzBoy

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all I can say is WOW!! Can we have some more info please Mercules? Did I miss something? Like, I thought you sold the car? No? I hope not......
Regards,
BenzBoy
 

Des

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Very interesting to read.

So, the quick fix (beside a dyno tune) is to put a sports air cleaner (american V8 style) and that should improve airflow/fuel/performance?

Sure sounds like it,



Would imagine it would be a matter of getting someone to modify the base so it fits the fuel injection setup,
 

Michel

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Sure sounds like it,

Would imagine it would be a matter of getting someone to modify the base so it fits the fuel injection setup,

You're good with pics Des :cool:

I recall seeing very recently (and my memory fails me) a picture of a 116 or another Benz V8 set up (I'm almost sure it was on this forum or maybe OzBenz) where there was a sports aircleaner (I even think it might have been the 4wd type with rubber for element) connected to a hose and a cold intake at the front...

Do you (or anyone else) recall that ?
 
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M

Mercules

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Very interesting to read.

So, the quick fix (beside a dyno tune) is to put a sports air cleaner (american V8 style) and that should improve airflow/fuel/performance?

Only if your engine is running lean - if i were to fit one to my engine now, it could possibly ping becasue the k-jet is no longer running rich. Best to get the mixtures tested before modifying the car... this will also give you a baseline to emasure your results as well.

Cam
 

Des

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Do you (or anyone else) recall that ?


Do you mean this one?

rusty450001.png

rusty450003.png

rusty450002.png

its a chevy V8 of some sort,


The easiest way I can see to increase the amount of air getting in would be to drill hundreds of little holes around the air cleaner,

or if you have legal access to a .22 rifle take it out into the paddock and shoot lots of holes in it.
Problem solved!
 

BenzBoy

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The colour of whatever is in the expansion tank might make me a bit concerned - :eek:
And that's before Hunter Des starts blasting with his shotgun!! :D
Regards,
BenzBoy
 
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J

JoeB

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how bad is the blow-by in your engine? and are you sure it's rings and not valve guides?

I assume you've done compression tests (wet & dry) on each cylinder and found a few low scores, yes?

There is nothing wrong with a little blow-by, and if you're not using truckloads of oil, then it's not anything to be concerned about too much, however if you're constantly oil-fouling plugs, have bad compression, hopeless fuel economy and bad emissions then I guess it is time to have a think about rings 'n things...

or maybe, your oil is simply too low in viscosity. You're not running a low-viscosity full synthetic oil are you? Is your tailpipe full of heavy black oily soot? Do you get plumes of smoke eminating from the rear under full throttle, or as you back off from a hard full throttle run?

I'm sure you've checked all these things out already, but sometimes the oil-fume in the rocker cover cavity is a top end thing and not always crook rings. If you have noisy tappets, you could have worn cam lobes, dud rockers and followers, which eventually lead to worn guides - but the easiest way to check is to run an engine flush treatment in the oil before you change, then use a straight 50 grade oil and see if the blowby is the same. if it is, and you are oil-fouling plugs, then it's time to pull down the engine. If it stops, then you will have just enough time to save all your pennies up for the upcoming rebuild / engine swap. :)
 

John S

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Mercules, I'm impressed by the 157 HP at the rear wheels as the desmogged motor was only rated at 190HP originally, its great that you could obtain the gains you did. I'm also pleased that the tuning was so good as I had no hope of getting it right, gave up and had Albert Ricci (West Star Autos) do it for me. For the ticking tappets try a cup of ATF in the motor as the high detergent content should clear out the hydraulic tappets if sticking is the problem.
 
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Michel

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Des,

Not this one mate
But one with (I am almost sure) an injected 116 with a wild contraption of an air filter

Mercules

I meant obviously with a leaner mixture ;)
 

SELfor50

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Great reading Cam!! You have gone where no 116 owner has gone before....or maybe a few with 6.9's have.. :rollseyes: anyway, great to see the measure in gains etc and the measurables as to how it was achieved. Very valuable information.

Am I right to assume that the beast has been running rich, which is why on a cold night with an induction setup I seem to get a better output?! I'm gettin' me a dyno tune to squeeze that little extra out i guess..

Looking forward to the footage!! :cool:
 

Styria

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What a great read, and totally surprising at that. The number of ponies - only about eighteen to twent off the best dyno figures I have seen published for 6.9's ! Now, here we are talking about a K-Jet 450, not the D-ype.

This certainly arouses some urgings as far as Gleaming Beauty is concerned . Rebuilt heads, excellent and well adjusted hydraulic lifters ,wonder what she'll show on the dyno ? This is going to be interesting when GB is finished. Thanks Champie for that, and also the points that JoeB has raised - all so very important in the overall scheme of things for a well running engine. Regards Styria
 
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BAR

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Very interesting reading. One can only imagine how conservative the factory was when originally quoting outputs.

Another thing could be that MB quoted lesser outputs for the ADR compliant motors than those in Europe. Now one finds that when the airpump is removed, there is slightly less load on the engine... every little bit helps in gaining power.

On another note, you should get in touch with Styria and press him into providing you a spoiler for you car. They just set off the appearance just that much more.
 

John S

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I believe that the Australian '76 antipolution motor was originally quoted at 190HP, the European motor was quoted at 220HP, but when driving them there felt to be a bigger difference between the two motors than the quoted figures. Advancing the timing and without the air pump probably regains a lot of omph!
 
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WGB

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I have the dyno recording of my 6.9 from when AMG69 had it tested July last year.

It says 168 hp at the rear wheels.

Mind you since that test was performed it now has 8 functioning plug leads, vacuum advance has been reconnected and a new timing chain (previously 16 degrees of chain stretch) has been fitted.

I would expect my 6.9 to put out more than the previous 168 rwhp now and the subjective feel is a significant improvement - particularly in low end torque - with these improvements.

Bill
 

Styria

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Hi guys, assuming the figures for Mercules' 450 are correct, where are all the ponies of ALL of the 6.9's I've seen published.

If you compare like with like, the published 6.9 dyno figures are WAY down. Can't wait to get Gleaming Beauty back on the road again. Regards Styria
 

s class

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One needs to be careful comparing results from different dyno shops.

Certainly this has piqued my interest in looking into tuning my cars this way.
 
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Michel

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Hi guys, assuming the figures for Mercules' 450 are correct, where are all the ponies of ALL of the 6.9's I've seen published.

If you compare like with like, the published 6.9 dyno figures are WAY down. Can't wait to get Gleaming Beauty back on the road again. Regards Styria

Some of those "ponies' might have died of old age :p :confused:
 
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