BIODIESEL & SVO DISCUSSION FORUMS






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Bio Diesel remap
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I am running an ECU remap that's supposedly pushed the stock 140BHP to 170BHP when running on Dino, this got me thinking there must be some improvements that can be made to the map when running on bio, advance injection timing,increasing fuel charge due to improved smoke point, optimize fuel air ratio etc All leading to more fuel efficient and increased power output when running on bio. Before i start heavily researching the subject has anyone else done this work using Bio-Diesel already no point re-inventing the wheel.


VW Passat 2.0 TDI with a BKP engine 86,000 miles on B100 and not going strong. Bio-diesel broke oil pump drive shaft! ..No oil pressure, dead turbo.
 
Location: Calne, Wiltshire, England | Registered: October 22, 2008Reply With QuoteReport This Post
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My Audi was remapped by a guy in Cape Town. 70 litre tank, on a trip I get 1200 Km, do not put your foot down while turning a sharp corner, otherwise you tend to do a doughnut if you're not careful, and the head rests are useful too.Jim.
 
Location: Cape Town | Registered: May 17, 2006Reply With QuoteReport This Post
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Oh yes, forgot to mention, the car has 240000 Km on the clock, about 200000 on B100, and at times I tow a trailer with nearly 2 ton loads, not really legal and really not too good for the car, but it takes it with ease. Jim.
 
Location: Cape Town | Registered: May 17, 2006Reply With QuoteReport This Post
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Few things to consider, biodiesel ignites easier but burns slower than regular diesel. CTANE is higher by 10 points or so. Is the reason an engine sounds quieter on bioD, less knock.

Second thing I've found is fuel pressure likes to be bit higher on Bio. Although it ignites easier, it atomizes harder than dino diesel. Viscosity related I believe.. So turning up the fuel pressure say 10-15% will help it that out a bunch also.

Third, Biodiesel has less BTU's, so to achieve the same power level as dyno, you need more fuel. Not gonna do much for mileage, but it's possible to get back what power ya lose on higher blends. I've experimented a fair bit with custom biodiesel tunes and big HP engines trying to get more power on Bio. Research studies show that oxygenating biodiesl has the potential to achieve this, similar to running alcohol vs gasoline, but it's gonna take some serious dyno time to find this right combo.

-K

PS. Looking for someone to do some custom tunes for my 05 CDI "W211" engine, ask your WV tuner who he suggests.

This message has been edited. Last edited by: Kenr34,


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Location: Southeastern Ohio | Registered: January 10, 2008Reply With QuoteReport This Post
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Ken my understanding of the start of injection required is 180 degrees from your understanding.
 
Registered: August 08, 2007Reply With QuoteReport This Post
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Didn't see where you listed a model year, so I'm going on that it's a standard Bosch common rail fuel system. That said, it probably uses multi-stage pilot injection before the main injection pulse. Stock main injection pulse is typically max of 25deg BTDC, with the pilot stages calculated off that value. So it could be like 30-40 deg start of injection best of my knowledge.

When writing Duramax performance tunes, we use a timing calculator speadsheet to map it off of fuel pressure, pulse width, and percentage of pulse requested before top dead center. That gives you a BTDC base timing number/map, and we sometimes turn off the pilot above 2400rpm to reduce cylinder pressure spikes.

Main thing is, let who ever is writing the tune know you run biodiesel and maybe back off the maximum main injection timing a couple degrees from what they would normally use.

-K


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Location: Southeastern Ohio | Registered: January 10, 2008Reply With QuoteReport This Post



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Hi Forgot to mention that my car is a VW Passat 2.0 TDI with a BKP engine (double OHC 16V) 140.0 PS Siemens PPD1.5 ECU P/N 03G906018CD Software No SN000F7600000

I definitely agree with Johann, my findings is that B100 has a slower burn, hence the reduced knock at idle and med-low revs on a mechanically injected diesel with fixed timing. And advancing the ignition on such engines restores the characteristic Diesel low speed knock, and significantly improves performance. I observed this on my Vauxhall Frontera which had a 2.8 Isuzu 4JB1-TC engine with a Zexel Injection pump, a Japanese copy of the standard Bosch one.

In cold weather it had a 5 degree advance if the engine coolant temp is below 7 degrees measured at the thermostat housing. When running on Dino diesel when the engine warmed up and the advance switched out you would hear the rattle reduce. If running on Bio it was like pulling on the hand break if you were accelerating at the time and the rattle would completely disappear when the advance switched out.

The passat doesn't seem to sound any different running on bio compared to dino, and the remap has more than made up for the loss of power caused by switching from dino to bio. I use B100 FAME not SVO, and in the spring summer and autumn i use Bio made from animal fats which also goes a long way towards restoring the power lost because of using bio.


VW Passat 2.0 TDI with a BKP engine 86,000 miles on B100 and not going strong. Bio-diesel broke oil pump drive shaft! ..No oil pressure, dead turbo.
 
Location: Calne, Wiltshire, England | Registered: October 22, 2008Reply With QuoteReport This Post
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Johann, after reviewing my bio timing notes, I corrected my post above. Haven't played with the timing curves in a while, only been focusing on fuel pressure and pulse widths.

Biodiesel burns smoother, or at a slower rate, not faster as I was thinking. That "slower' burn rate changes the torque curve vs engine RPM, because peak cylinder pressures are less and occur at later crank angle. Does that sound correct?

Cineman, Here is a post about results in a TDI and dyno tests that explains how this burn rate plays out.

http://www.gassavers.org/f9/bi...-5821.html#post96439

Also if you have time, you should check out this review of major studies relating to biodiesel and engine performance. Should help explain things in better detail.

http://abe-research.illinois.e...ncesAndEmissions.pdf

-K


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Location: Southeastern Ohio | Registered: January 10, 2008Reply With QuoteReport This Post
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Interesting reading the second one is some what long winded and academic with the wording. Interesting none the less. So perhaps there isn't much to be gained by experimenting with the map, i guess it would need to be dyno tested to get accurate results.


VW Passat 2.0 TDI with a BKP engine 86,000 miles on B100 and not going strong. Bio-diesel broke oil pump drive shaft! ..No oil pressure, dead turbo.
 
Location: Calne, Wiltshire, England | Registered: October 22, 2008Reply With QuoteReport This Post
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This is my compilation I have come to follow;

Biodiesel has a higher cetane rating than mineral diesel. Cetane = ease of autoignition, octane = resistance to autoignition. The reason bio makes most engines quieter is that as its being injected it starts to burn were mineral diesel is injected, nothing happens, than more diesel is injected, and when it finally explodes, all of it explodes which creates that cylinder pressure spike that creates the noise that a lot of diesels make.

So, in a sense, biodiesel burns faster in that it STARTS to burn faster, but once lit, the flame front will be slower(?). Mineral diesel will start to burn slower (as in the dwell time between injection event and ignition), but once lit, the flame front moves faster.

So using biodiesel has the effect of advancing the timing on its own; reducing the dwell time between the injection and the start of combustion.

Modern diesels are getting quieter running mineral diesel by using multi-shot fuel injection which injects a tiny amount of fuel and then when it starts burning the big blast of fuel is injected. Less cylinder pressure spike, less ignition noise.

On density, BD has fewer BTU per kilogram, but it is quite a bit denser (BD = 885 kg/m3 vs dino at ~840 kg/m3) so volumetrically the energy difference is less.

I've lost the references over the years to the who-said-what bits-and-pieces of the above paragraphs. Smile But no one has ever called me out on it being wrong.
 
Location: Southern WI, USA | Registered: May 18, 2006Reply With QuoteReport This Post
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Thank god someone else could explain that better..

-K


Recycling & Green Fuels Research: www.altfuelsgroup.org
Ozone Eating Toys For Big Boys !!: www.suncoastexotics.com
Carefully Maintaining A Carbon Neutral Footprint...
 
Location: Southeastern Ohio | Registered: January 10, 2008Reply With QuoteReport This Post
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Thank you Ryan, that makes things much clearer however i'm still a little unconvinced about not advancing ignition. I guess its the slower flame front of the bio that accounts for the power improvement gained by advancing the ignition, when i observed this the engine speed would have been fairly high as i would have been going up "Snow Hill" a fairly steep long hill on my daily commute to work. So overall Advancing ignition a few degrees would probably be a good idea if it was found to make an improvement on a TDI engine without causing any additional engine noise. As for the Cetane rating or lower ignition temperature why does the use of bio (FAME)require more cold cranking to initially get the engine started and smokes for longer once running compared to when running on dino? Again this was observed on a direct injection engine without heater plugs turned off (a relatively new gen-set where heater plugs have to be manually activated before starting). i will perform some tests by dripping bio and dino onto a hot surface and see which ignites first.


VW Passat 2.0 TDI with a BKP engine 86,000 miles on B100 and not going strong. Bio-diesel broke oil pump drive shaft! ..No oil pressure, dead turbo.
 
Location: Calne, Wiltshire, England | Registered: October 22, 2008Reply With QuoteReport This Post



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