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Discussion Starter #1 (Edited)
Hi All
Just back from the Dyno with my 2008 EFI Thruxton it has an Airbox mod kit , AI removed and a pair of TORs Nothing else.
After the first run it was found that it was running very week which was to be expected.
The Tuneboy program was used to add about 10% more fuel across the rev range at 60% - 100 % throttle position. This vastly improved things and a few more runs resulted in an acceptable AFR and a max of 66 bhp @ 7243 rpm with 55 Ft/lb of torque @ 5248 rpm.
I was invted back to see if further improvements can be made to get rid of the over rich Air Flow Ratio at 3000 rpm and have a general tinker with the settings throughout the throttle positions as time was a bit short today.
So my conclusions are -
Cut your own air box up and get a couple of K&Ns , you can do the AI removal if you want as this can be sorted using the Tuneboy ,and TORs can be used if you don't want to go for max power ,they may knock off about 2-3 HP .
If you do the airbox mod DO NOT use your bike untill its been on the Dyno or you may be in danger of melting somthing.
With the Tuneboy you just pay once for the unlock ( £70 in the UK ) thats it you don't buy the program or lead the tuner has all that , cheap as chips !
 

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I think you mean its lean at that rpm its not rich any where that i see.(lower the number the richer it is.

I agree with Mike, it is lean from approx. 2750 to 3800 RPM, presumably under acceleration. I suggest asking the dyno operator to also test A/F under steady cruise in that RPM range, to determine if the mapping is also lean under steady cruise - it may not be.
 

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Discussion Starter #6
Hi Chaps
Thank you for your observations and comments, yes it is running a bit lean between 2.75k - 3.8k as you say ,sorry I read the graph wrong ,the operator is going to go through all the throttle positions ect to obtain an improved AFR in a week or so .
I doupt I will be using the bike much before then as it has just started snowing.
I was pleased with the smoothness of the power curve and the final bhp. I have not had an EFI bike on the dyno before .
Thanks again. Alec
 

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Nice looking dyno run...pretty impressive given the fairly restrictive exhaust. I'd be pleased as punch with that power output. I guess there's something to be said for the FI potential over that of the stock corks...umm....err...carbs. :)

Too bad there wasn't an initial run to know exactly what was gained...

Cheers,

--Rich
 

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Discussion Starter #8
Hi
It would have been good to do a std run but I bought the bike with the TORs so wasn't an option. It did sound good in the booth when it was reving up to 8k .
 

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guys that din hp(metric hp ) not sae like most dyno runs on here thats somewhere around 60 to 63 sae hp ,about the same as a carb bike with same mods but its running good ether way you look at it.
 

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Not sure? but is says BHP - Brake Horse Power on the chart. I thought HP was HP i.e 1 HP = 746 Watts according to any standard.
I thought the DIN standaard used ps which is based around the Kilowatt. I'm sure someone will let me know if i'm wrong (I used to teach Heat Engines/Thermodynamics in College but that was a long time ago).
 

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Discussion Starter #11
Hi
I think metric hp is 98.6% of mechanical hp , is that right ?
Anyway ,I was hoping for around 62hp as the British Custom EFI had 64.3hp and had Preditors which should give a couple more hp.
As you say ,it should be the same as a carb model with the same mods, just easier to dial out any dips in the power curve once on the dyno.
 

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yea thats right as far as raw hp goes but the correction factors take more hp away with sae numbers.I think yours is about where it should as far as max hp.
 

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DIN typically shows higher #'s than SAE.

This link is to an interesting technical article about atmospheric conditions & CF's, including SAF & DIN calcs: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1678-58782003000300010

Have fun with that one. Abstract: "This work evaluates proposed methods to correct engine power output as a function of atmospheric conditions. The analysis was made through experiments carried out in a vehicle on the road, under different temperature, pressure and air humidity conditions. The vehicle had a four-cylinder gasoline-fuelled engine, with multi-point fuel injection system, variable intake pipe length and variable intake valve camshaft position. The vehicle was tested at sea level and at 827 m above sea level, corresponding to atmospheric pressures between 1027 and 926 mbar. Air temperature varied from 22,8 to 33,8 °C at the test locations. The measured performance parameter in the tests was the vehicle acceleration time. The acceleration times from 0 to 400 m, 0 to 1000 m, 40 to 100 km/h and 80 to 120 km/h were all recorded, leaving from an initial vehicle speed of 40 km/h. The engine power curve obtained in laboratory under a standard ambient condition was corrected to the conditions of the road tests by the correction factors proposed by the methods under evaluation, and the corresponding acceleration times were calculated and compared with the measurements from the road tests. The evaluated methods for power correction were the following: DIN 70020, SAE J 1349, JIS D 1001 and ISO 1585. The SAE J 1349 method provided the best approach between the experimental and calculated acceleration times."

For those who wish to skip the engineering mumbo-jumbo & go straight to the conclusions, here they are:

"
Conclusions
The atmospheric pressure was observed to be a more relevant parameter to influence the engine performance than the air temperature. Road tests confirmed that the acceleration time is increased with increasing air temperature and decreasing atmospheric pressure.

Trends observed in the results indicate that variations on the atmospheric temperature and pressure are more influential on the power output from the engine than on the road-load power.
The power correction factors evaluated in this work which showed the closest results to the road experimental data were the ones recommended by DIN 70020, SAE J 1349, and JIS D 1001 standards. From those, the correction factor indicated by SAE J 1349 standard is the one which produced the best results.

The vehicle acceleration time does not have a dependence on atmospheric pressure, temperature and humidity as described by the engine power correction factors evaluated in this work. Direct measurement of wheel torque on the road may allow for a better evaluation of the power correction factors."

Here's another interesting summary about comparing dyno runs: http://www.bishopsperformance.com/dynoinfo.htm

And an explanation of various power calcs:
http://en.wikipedia.org/wiki/Horsepower
 

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I agree air pressure changes hp more then temp.A few years ago i built a dyno for a buddy of mine for gokart race engines .IT was set up with a weather station and all like the dynos we use.I talked to the guy that made the program he told me back then to forget the c/f and use raw numbers because they dont work,he said keep a book with weather at time of run .Make runs with different weather cond. Then you know how to tune on race day.Truth be known the raw numbers you get are what you put to the road the c/f numbers are should be numbers that dont work out that way.One thing the numbers dont show on a air cooled engine is that air cooled engines can be to cold or to hot to put out max power. water cooled engines run close to the same temp inside on a cold day as they do on a hot day.
 

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yep with raw numbers you can say well it made that much hp one time anyway lol.Then I wonder how much one dyno reads comparede to another.The 2 i use here in town are about the same on raw numbers.
 
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