This post is designed to aid those seeking tuning help – a request I often get. To tune a car accurately valid data is required. But what I find happening to my NAM based customers far too often is the following scenario: a customer with a heavily modified engine such as a cylinder head* requests an adjustment in his ecu air/fuel mapping. I request data (I prefer test track data). The customer sees his local dyno shop and sends graphs depicting spectacularly high horsepower numbers. The trouble is, more often than not, the data is invalid. I inform him of that and he invariably gets upset. Let me speculate as to the cause (I hold an advanced degree in psychology): I think the customer gets upset because he thinks the dyno is a race rather than a tuning tool and he lost. However, the dyno is a tool that requires accurate input: garbage in; garbage out.

In researching MINI dyno results I happened to come across a sight with a veritable plethora of dyno information that I encourage all dyno junkies to read: http://www.rri.se/index.php?DN=23 . It even has 2002, 2005, and 2007 certified results for the MCS. Their data corresponds to what I find almost precisely: MINIs make pretty much what the factory says they make; even a shade less.

The comeback always is the factory tolerances are all over the map (that is untrue however) and mine made X amount over the factory number. And even if you tell me that test deltas (in percentage) are what matters and not the end number I will tell you that is true only if the tests were controlled. Not only does the Rototest site speak of this the DMH site does as well.

Bottom line: To aid in tuning valid data is required.

*Unprofessionally ported intakes and modified bowl work lead to many tuning issues relating to fuel puddling, an issue that cannot be addressed with ecu tuning.

 

Excuse me for my ignorance but I don't quite understand your post. As you have posted different dyno numbers that is usually limited to hp and torque. Beyond environmental factors related to that particular dyno such as intake and exhaust temps, what other data do you need?
Most of the discrepancies on NAM have to do with different types of dynos producing varying numbers on the same car. Some say a peaked out M45 sc only mini is around 225. Others have posted numbers around 240. Helix claimed they'd seen nothing over 200. I have gone to 2 different dynos in the same week under similar environmental conditions and noted over a 30hp difference.
So when you say the mini makes pretty much what the factory says, on who's dyno? Is there a particular type of dyno that's "better" than others?
And beyond these types of descrepancies which keep many of us distracted, how is the dyno a useful tool and what other info do you need to tune?

 

And excuse my ignorance.. but are they not showing the tested Wheel Power compared to stated ENGINE power... It seems to me their not comparing straight up...

Also, I've recently read several articles and posting about the 335i Coupe dyno-ing close to the exact numbers they posted. However in WHEEL power and so that puts it at 330-ish HP and 350-ish LB-FT... Not just independents but very trusted and respected tuners...

 

I posted the link for educational purposes. One of the things I found of use is the section on rolling road testing: Why powertrain performance measurements http://www.rri.se/index.php?DN=30
Noted in the article are issues related to their use.

To answer why valid data is needed is because without it all else is useless. It's definitional.

 

there are differences in engines.. from S to S... you can ask all of the AZ mini owners who had thier cars when I got mine... they were moedded with intake, pulley, exhaust... things of that nature... mine was stock... and some I could accually pull... some were even.. and some were only barely getting away... maybe it's how I did my breakin... maybe I was just lucky... SO I took her to the dyno... that is another story

as for tolorences...even the heads are so uneven from head to head... the ports are not always in the same spot you can see this from looking at them side by side... are they close enough... sure.. LOL... what about compression.... I have seen 140- 170 between engines.... surely the tighter motor stands to make extra...

I agree Dynos are a fantastic tuning tool... they have alowed us to achive amazing things in auto performance...

at the end of the day the dyno is a great tool... for measuring all kinds of things... especially deltas between mods... I have said it before and I'll say it again... I don't care if the dyno reads 50 WHP... after I add my mod if it reads 100 WHP then I know I made 50... and that should be the case accross the board... reguardless of the accual #

 

Your last sentence said it all. Before and after on the same Dyno

Longboard

 

see! I had a feeling mine was 200 stock and a special cooper motor unlike the rest ok so not really, but I do plan on taking my cooper to the dyno soon.

 

To answer why valid data is needed is because without it all else is useless. It's definitional.[/QUOTE]

Of course valid data is the most useful thing for a tune. In the 1st post, you said folk call in and give dyno numbers but they are useless for tuning. What is the data that you referred to that is needed beyond hp numbers?

 

The air fuel ratio, atmospheric conditions, and other factors that go into the power number (and they are listed in the link I posted to the white paper).

 

I'm reading this and I want to know (sincerley) why my car with the below mods pulled 12-20 more whp than cars with similar mods or JCW cars on the same dyno. Me car was the last of the day in the warmest part of the day. 181 whp.

 

you got what we call... a wednesday build... CONGRATS!

 

How's the moose?

...can't wait to get this car properly tuned....

 

From your signature it looks as if you have changed the reciprocating weight of your engine -- lighter tires and wheels. This affects how fast your engine accelerates and that figures into the hp formula of inertia dynos. These types of changes make a tremendous difference. Also, as I have noted before and Rototest notes in their article tire rubber compound, design, wear, pressure, and diameter; wheel load, relative slip, and tractive force (tie-down pressure) are all factors that are often overlooked when using inertia style dynos. So is the operating temperature of your engine: IAT, water, oil, and gear oil. Until you can control these variables the data is in fact invalid: no comparisons can be made.

 

The reason that different inertial dynos ( the inertial part is important) read differently is the differences in the math used to calulate hp from measured torque. They all have a different standard. This is why I don't use an inertial dyno for testing, r&d and tuning. Here's a question. If your readout from local inertia dyno X indicates that your car has 170lbft of torque, how much did the dyno actually measure at the wheels?

 

...if atmospheric conditions, car operating temperatures, and tie-down pressure controlled then yes.

 

Don,

As I think I mentioned when we chatted, I mostly want the dyno as a check for afr. Is there any reason to believe afr could be affected with various dynos (assuming relatively similar atmospheric/climate conditions)?

 

dmh. . .

Atmospheric conditions are accounted for by SAE correction, and although its not perfect, it will reduce the variability due to almost nothing from that factor. Car operating temperature is a very easy thing to control, and tie down pressures, although they will affect things slightly, they will not create a very large variation (all three factors, if SAE correction is used, would keep the total variability due to those factors to no more than +/-3%, its probably not even that bad).

The way you post, you sound like you think its +/- 10%. The reality is, dyno variability is small enough compared to the magnitude of the pwoer gains from a lot fo typical mods that you CAN draw conclusions from dynos that are very reliable. If someone says the dyno showed that their car gained 7.58946 hp, then yes, they are full of crap, but if you use the same dyno, w/ SAE correction, and don't go out of your way to change the other two factors, it can be a very useful tool for tuning.

As far as fuel tuning though, a wideband o2 is much better. Frankly, I think its kinda sketchy tune a car without being there. How you think you ever get "valid data" from someone sending you an A/F chart from test track data OR a dyno is beyond me, seems like you'd need to sit down at the car with wideband to accurately tune it (or at least go through a couple iterations), you're probably getting pretty close by using the data and tuning remotely, but as you said, "valid data" is gonna be awful hard to come by without actually having the car on site isn't it?

 

Just another question that will probably go unanswered, but how and what method are you guys talking about for tuning these Minis. This is a Mini forim afterall. What method/software is being used to make these afr changes?

 

I use the Unichip Q

 

You do not seem to fully comprehend how this works. The atmospheric conditions are entered into a formula. The accuracy of the barometric pressure gauge is vitally important. SAE corrections are by no means perfect with a forced induction engine; actually it is far from perfect. Controlling the operating temperatures of a MINI is tremendously difficult. How you strap the car to the wheel is also not as easy as it sounds. Traction, as previously mentioned, should not be overlooked. Ever try to dyno a car with -4 deg neg camber?
Dynos such as DynoJets do not even guarantee accuracy to +/-5%. That means 210 could be the same as 190. And unless you are on a Dynapack (LDG owns one) or similar dyno your transmission is not under full load.
The link I posted was intended to help with education but what it seems to have started is defensive posturing. Anyone care to respond to LDG’s questions?

 

The Rototest link has a lot of good data. RRI. Rototest REASEARCH Institute. Not Rototest Marketing and Internet Myth Institute.

Piggybacks like Unichip don't count 'cause they are only signal conditioners and have virtually no effect in closed loop and minimul in open loop. The associated misrepresentation of airflow to adjust afr also has adverse effects on engine timing.

 

So what do you suggest to tune the ECU for optimum AFR, if the Unichip can't be counted on?

Currently, I'm running without my Unichip anyway.

Incidentally, my posts aren't meant as incendiary devices, nor are they meant to encourage them...

 

I tune the factory ecu. If I make a mod that changes ve like a head or cam I modify the appropriate tables. If I want to enrich or enlean at any load point, I make the changes in the appropriate tables. If I want to modify base timing tables or scalers, I can make those changes.The Mini ecu is very complex and is a torque management based system with obd2 thrown in for good measure. The method described above has been the only effective way that I have found to get the desired results. I have used piggybacks for years and still do but only to make fine adjustments over basic changes to the underlying recalibrations.

 

Right, SAE correction isn't perfect, but its not terrible. If you are tuning on the same dyno though, only the air temp and humidity come into play though, altitude won't affect things, and assuming the dyno isn't on the back of a truck, temp and humidity will at least be close.

Traction issues are rarely a problem for a car with as little hp as most minis (twincharged and we might need to consider it more carefully), and the large amounts of negative camber also present a fairly special case, not to mention, traction issues are usually noticeable (you'll see it if your car is slipping a lot on the dyno). For most cars that we're talking about though, these variable present little complication.

And I won't refute that a dynojets accuracy is +/- 5%, hoewever. However, the same dyno is usually fairly PRECISE if not accurate (i.e. will read the same run after run). The same dynos precision is certainly less than +/- 5%, at least the dyno I've run on read the same hp within +/-.5% each time I ran on it on the same day with the same strap down (to take out the weather and tie down variations).

I'm not trying to be defensive here, comparing dyno runs accross the country is admittedly inexact. However, for identifying the effect of a mod, the SD of measurement is sufficiently low that meaningful conclusions can be drawn, if its on the same dyno, as operators tend to use fairly consistent tie downs, and the weather doesn't fluctuate TOO drastically (assuming that this dyno isn't moving accross the country on a truck or something SAE correction will at least be fairly consistent if not accurate)

I agree with you though that a dyno chart does pretty much nothing to allow you to tune, wideband 02 data is a much more useful tool. I was only claiming that even if you did have proper data, it'd be better to do a couple iterations of tuning to see how the closed loop adapts, thats all I meant by its better to tune with the car on site.

Sorry if I offended you or came off as confrontational (or as "defensive posturing"), I agree in large part with most of what you're saying, but I still think a dyno can be a useful tool (not the only tool, but a useful one at least) in modifying a car and wanted only to clarify that.

 

So if someone with a modified MCS (me) came to you for "bespoke tuning" (as it's called on your website), and wasn't particularly looking for additional mods, you will fine tune the set-up on your dyno and/or driving tests, using the factory ECU?

Of course this is significantly more involved than a one size fits all "flash".

If this were done, and the dealer subsequently reflashed the ECU during a warranty service (this happened to me on my first MCS, despite my requests), how would I get your tune back onto the car?

Especially since I'm in Atlanta?

I wasn't aware that anyone on the east coast had managed to get into the code of the ECU.

If you have, that is BIG.