one measurable difference might be lap times then...most of the top level racers are consistent enough, have their cars sorted, worked out the best tyres etc...so, if any significant horsepower gains become available it might/should show up in their lap times...

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"Show me the Mini!"

This reminds me of the old fishermans scale of fish, " It was this big I tells you -insert indicative hand gesture here- "

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Nick

http://www.ausmini.com/forums/viewtopic.php?f=3&t=86675

Just remember, "To finish first, first you must finish"

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Have a Nice Day.
If already having a nice day please disregard.

Lol a good inflammatory post to keep this thread going. My motor hasn't missed a beat since it was built and anyone who knows me knows that I'm not shy at giving it a rev
As mentioned, the motor has done around 2000kms of street driving, 8 runs at the drags and gets driven to work regularly (like today!). I took it to Rylstone this year and also on a few MITG runs etc.

It may not be the biggest hp monster but it's pretty solid and I'm confident it will make good numbers on any dyno (great numbers for a roadie)

I'd class that as finishing the race, how about you Mr Walker?

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1968 Mini-matic - 1340cc, 45 weber - 92hpatw, 14.5 @91mph, GrandmaSpec

Hi 9YaTaH
Using Lap times to compare HP in historic racing will never work very well as there are far too many variables, Track condition,car setup,gearing and the most important the driver. I build engines for and help setup some of the fastest under 3 liter group n cars in the country and HP is no substitute for a well sorted car and a fast driver,just a driver change between cars with the same HP can result in quiet a few second's difference.

1/4 mile times and a knowledge of the weight of the car is going to be far more accurate and even then there are still a lot of variables.

Get your time slips out boys

Last time I measured my quarter mile from a standstill it was 24 seconds at ~95km/hr...

Hi GR and Matty.

I just want to be clear that I meant none of my post to be negative in any way. Quite the contrary.
I have the utmost respect for you guys and Greig as I don't know of anyone that has got more race minis going than you guys.
You have always had time for everybody and have been the leaders in R&D for the A series and race minis.

You have always struck that tricky balance between reliability and power for your customers and the results show this.

I cannot thank Graham enough for what he has taught me and allowed me to discuss and bounce ideas off him.
I don't know anyone as generous with their time as Greig.

I thought my posts were actually confirming this but I can see they could be taken as otherwise.
I wasn't questioning the numbers put up, I was simply trying to take out some of the confusion they may create. Trying to help others to keep up.
I know these things are second nature to you guys but the exact confusion of this exact is 'people trying to compare different dynos numbers'.

I did state that I 'completely trust the repeatability of figures from your dyno' and I wouldn't have enjoyed my racing without you guys.
As I said you have always calibrated your dyno the same way and used the same CF every time I have been there, so I trust the comparisons.
Other dyno people may calibrate differently or use different CF's??

As awesome as it would be to have a comparison between everyone's motors or even better, kick the Poms ass, it would only work back to back.
Matty, you are correct that more numbers may make less contribution to the thread but high Kudos to you for posting them!

my green car has seen 93Hp at the wheels on the rollers I use to occasionally check my car for tune. My mates engine I most recently built showed 108hp on the same rollers. People have told me that is too high and others have told me that its too low??
I don't know if these rollers are a fibreglass tape measure or a steel one but I use the same ones each time.

cheers guys. Ben

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The formula for the length of a piece of string is simple: Twice as long as from one end to the centre!

well,,, i have said this before a number of times-
-->years ago,,, i had my green S (roady 1510cc) on a few dynos here in Brisbane & within the same week/climate etc

just to see who`s reads high & who`s reads low etc... simply because i was sick of people telling me they have "x" HP when clearly my roady flogs their "x" & i was pretty certain mine only had about 80Hp (atw)

so,,,they ranged from 85hp to 92 to 97hp to 106hp & then an awesome 116hp

go figure hey?

now i already knew the high ones were going to be high as i`ve heard it all from customers & friends previously,,, i just wanted to see "How-High" & which ones.

fudging dyno figures is a bit like fudging flow-bench figures... just to keep a customer happy "Thinking" they have an awesome head/motor/tune etc

if you use a reputable tuner/dyno & keep using the same one for comparisons of the work you do/change/improve/try/ etc,,, then all is well.

to find the best power (in my eyes/books) would be to find the highest longest flattest torque curve in an engine that has proven revs & years of reliability,,, that`s my 2 cents worth

heaps of people make engines rev to 7000 or 7500... some have "Reasonable" power... & some still go bang...

But--> if you can make one rev to 9000,,, have an awesome torque curve (high flat & long & starts early) & doesn`t go bang,,, then you have a winner

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No offence intended here but--> anyone writing a book about minis 30 years ago may not have experienced such worn or stuffed-with components as we are finding these days.

You should put your heart & soul into everything you do.

I reckon your 1510 would see 9000 often.

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The bitterness of poor quality (or Crappy Workmanship) remains LONG AFTER the Sweet Taste of Low Price is forgotten.

Hi Matt
Your so right when it comes to drive on dynos, when we were having dyno days down here I run my LS with a RE13 cam, so next time I put a RE282 cam in it on my dyno we made around 25/27 HP more when we went back to the dyno it made 1HP more, now at the same time I had BEN's turbo small bore on the dyno and it made the same HP as my LS one or two either way, but on the drive on dyno there was 15HP difference in his favour.
Now when we all went to the drags I think I beat him by a tenth or a thousand of a second, but in my books the same time so how does that add up that's why I like my dyno every thing is the same every time apart from the CF.
Graham Russell

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"It's better to be not informed than ill-informed"

Understand the variables well...just that some can be very consistent with lap times when they get a good run...but not many people are going to crow about a HP advantage

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"Show me the Mini!"

I'm confused.

It seems to me that one engine dyno is being questioned.

So if all was above board instead of making offers of bring your engine down why don't you just state which SAE correction factor you use? which really doesn't make any real difference if your using the current standard. Although variation of the correction information can be quite different if it isn't taken whilst the engine is actually running. No doubt you have an accurate live feed.

HOWEVER, more to the point, why not post the dyno being calibrated? Surely that ends the speculation?

Just a suggestion.

As for 1/4 mile times there as big a waste of time as a rolling road.

Tyres - size, brand, compound, age.
Wheel alignment - toe, camber.
Ride height - weight transfer.
Final drive ratio.
LSD or not.
Gear set.
Drop gear.
Vehicle weight.
Vehicle weight distribution.
Could go on for ages before getting to HP

So what do people think?

Run around speculating about this and that dyno and CF

OR

See the one in question calibrated which by the sounds of it is done regularly and shouldn't take long

Surely not calibrating it is as good as an answer anyway?

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Breaking heaps of stuff isn't the same as R&D since the "R" implies you actually did some research

G&H is the most applied practice by performance engine builders

G = Guess & H = Hope

_________________
Have a Nice Day.
If already having a nice day please disregard.

there have been other threads that have questioned the correction factors, consistency, calibration methods etc of dynos viewtopic.php?f=2&t=81461&hilit=sae ..... so much so that i did some investigation of the standards and the factors involved.

my interpretation of findings was ( and is)
1. that Correction Factors are only allowable up to 7% at a maximum.
2. some dyno readouts use the correct CF but display it in a fashion that looks to refute rule 1. ( they may list CF as 1.57 which is really 100.0157
3. CF are almost universally in the range.993-1.07 ( see rule one 7%)

in my fact finding, i must say the people contacted were extremely helpful and open in their answers

from emails with Mainline dynos
my email

Hi

Hoping you can help me with a readout sheet from one of your mainline awd dynos.
i am confused by the correction factor on the printout
Data was :

Cr SAEj607 2.89 / based on ambient temp 20.9 C, 1015 mbar, airdensity 98.2 % and rel humidity (I think) 83% ) tried to cut and paste the readout but beyond my skill.

I am used to seeing correction factions stated as near 1 eg .98 or 1.06 never seen 2.89

Not trying to cause a stir ( as i said the results as realistic ) but wonder what the 2.89 relates to exactly ( i usually put the figures into a formula.

Could you assist help me understand please. Regards Darryl

The reps response
Hi Darryl,

The "2.89" refers to 2.89 % power correction being made to the raw power data.

Our systems have an automatic weather station that constantly updates the environmental conditions, which are than used/ applied to the SAEJ607 correction factor. The correction can be positive (add) or negative (subtract) a particular power percentage value to bring the results back to a standard testing environment.
The correction factor is 1.0289 ( not 1.289)



and from the Society of Automotive engineers ( ie the group that make the SAE standards)

from me
Hi there Darryl here Cairns Australia.
If it is not too much trouble I wonder if this could be directed to someone with good knowledge of SAE J607 & and J1349
In regards to correction factors - i have seen interpretations as to maximum variances allowed
in different references i see 3% max for altitude
and in another 7% max in total variability.
in using the formulae

where: cf = the dyno correction factor
Pd = the pressure of the dry air, mb
Tc = ambient temperature, deg C
are there minimum or maxima ( using the assumed temperature ranges)
Thanks you for your time in answering this
Regards Darryl

and the response
Darryl,

SAE J1349 puts constraints on the range of dry air supply intake pressure (90-105 kPa) and intake temperature (15-35C), but it also limits the total ambient correction factor for naturally aspirated engines to 3%. The ISO standard 1585 for road vehicles allows the higher limit of 7% for naturally aspirated SI (spark ignition)engines and goes up to 10% for naturally aspirated CI engines.

The SAE standard is intentionally more stringent because we were trying to address a problem with some manufacturers overstating their power levels.

So again

7% maximum variation allowed not withstanding however many variables are considered...
there are operator factors such as clamping of tyres, tyre pressures, where the weather station is, but geerally these become a set standard for that particular workshop etc so as to get repeatability within the one dyno facility

so this is why our UK bretheren are more used to talking about 150 bananas or somesuch thing rather than getting stuck on the measuring yardstick ... the same day same dyno shoot out to compare different engines or same dyno each time to look at different states of tune on the one engine over time

totally my thoughts now

if you see a wild CF like 2.8 0r 1.5 then check if it is a mainline dyno or maybe others read like this also AND do the checking maths if raw hp is 100 and the CF hp is 102.8 then the data is being applied correctly but the CF as we see it (2. looks bodgy... if the raw data is 100 and the result presented is 280hp ????

AND i am not questioning the accuracy of any of these dynos....

my two cents.... i need a cuppa Darryl

Sorry wrong thread