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Kingsoup

Bigger Injectors to Adjust A/F

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Hi there! I'm intersted in E85 Conversion technology and I had a thought or two.

 

It seems that besides making sure you are corrosive resistent in your fuel system, you simply need to run about 30% longer duty cycle on your injectors to make up for the change over.

 

I was thinking that a normal aftermarket Air/Fuel controller would do the trick, but then you are tricking the airflow meter by a large percentage and you would mess up your timing advance curve along with it.

 

Couldn't you just replace your injectors with some that are approximatly 30% larger? In the Toyota world, for performance people replace their injectors all the time and use some kind of A/F adjuster to compensate.  But assuming you wanted to run straight E85 all the time, couldn't you just put in 30% larger injectors and call it a day? (say replace 440cc with 550cc, or 182cc with 230cc)  There are so many different injector types for used Toyotas you really would have a pick of the litter for something to replace it with.

 

I guess though this wouldn't be terrible useful if you wanted to run Gasoline as well.  Anyways if this has been covered before somebody please link me!

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Kingsoup,

 

Welcome aboard!

 

Yes,  Bigger injectors will do it, but may not run well on gasoline again.  I've herd of people going 12-15% bigger.

 

Most standard cars can go up to around 40% alcohol with the origanal injectors on E85.  The Quote below is referring to near straight alcohol so you may get away with less then 15-20% increase with E85.

 

FUEL INJECTION SYSTEMS

Since some vehicles are equipped with fuel injection rather than carburetors, we will briefly touch on the use of alcohol with that system. There are two important factors in a fuel injection setup: injection timing and control jet diameter. Fortunately - since many systems now use an electronically controlled timing sequence - injection timing is not critical in a fuel injected engine. Neither performance nor economy improve substantially by either advancing or retarding the injection timing process.

 

Control jet diameter, on the other hand, is an important factor. If you increase the size of the control jets (which are the equivalent of the metering jets in a carburetor), the engine will operate well on alcohol fuel. An increase of 15-20% is all that's necessary to accomplish the conversion. (Ignition timing should, of course, be advanced as explained previously.)

 

An interesting feature of the fuel injection system is that it doesn't require any gasoline during the cold weather starting process to fire the engine up. Since the fuel is injected at a pressure of about 250 PSI, the alcohol fuel is sufficiently vaporized to ignite easily within the combustion chamber.

 

FROM:

http://www.alcohol4fuel.com/id32.html

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Interesting! 15-20% is not that much at all.  Assuming you had the capacity with your stock injectors to go 20% higher max duty, then you could just use a simple A/F controller to make the adjustment.  I'm pretty sure units like the Apexi SuperAFC can do multiple settings, so you can run stock for Petrol and 20% increase on E85.

 

In that case, heck almost anyone could run E85 with a A/F controller, you can get them on Ebay for 150$ US I think.  I'm also pretty intersted in the claimed cooler combustion temps of E85 over Gasoline.  I wonder what the potential Octane rating is comparable to Petrol? Guys with Turbo'd engines would find it most interesting! (that includes me!)

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Interesting! 15-20% is not that much at all.  Assuming you had the capacity with your stock injectors to go 20% higher max duty, then you could just use a simple A/F controller to make the adjustment.  I'm pretty sure units like the Apexi SuperAFC can do multiple settings, so you can run stock for Petrol and 20% increase on E85.

 

In that case, heck almost anyone could run E85 with a A/F controller, you can get them on Ebay for 150$ US I think.  I'm also pretty intersted in the claimed cooler combustion temps of E85 over Gasoline.  I wonder what the potential Octane rating is comparable to Petrol? Guys with Turbo'd engines would find it most interesting! (that includes me!)

 

$220 http://cgi.ebay.com/ebaymotors/APEXI-SUPER-AFC-AIR-FLOW-CONTROLLER-SAFC2-SAFC-II-SILV_W0QQcmdZViewItemQQcategoryZ33553QQihZ010QQitemZ200002059399QQrdZ1QQsspagenameZWDVW#ebayphotohosting

 

still far less than going FlexTek $500-$750

 

 

Octane is around 100-105 for E85

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Hi there! I'm intersted in E85 Conversion technology and I had a thought or two.

 

It seems that besides making sure you are corrosive resistent in your fuel system, you simply need to run about 30% longer duty cycle on your injectors to make up for the change over.

 

I was thinking that a normal aftermarket Air/Fuel controller would do the trick, but then you are tricking the airflow meter by a large percentage and you would mess up your timing advance curve along with it.

 

Couldn't you just replace your injectors with some that are approximatly 30% larger? In the Toyota world, for performance people replace their injectors all the time and use some kind of A/F adjuster to compensate. But assuming you wanted to run straight E85 all the time, couldn't you just put in 30% larger injectors and call it a day? (say replace 440cc with 550cc, or 182cc with 230cc) There are so many different injector types for used Toyotas you really would have a pick of the litter for something to replace it with.

 

I guess though this wouldn't be terrible useful if you wanted to run Gasoline as well. Anyways if this has been covered before somebody please link me!

 

Kingsgroup,

 

Sorry for the long response; but, I believe in being thorough.

 

First off, let's talk about corrosion.  Many many "experts" confuse E85 Ethanol with Methonal and the 70s version of Gasohol.  They then rightfully conclude that E85 Ethanol is just as corrosive as the other two.  I suspect some of this is a lack of research and knowledge into the differences and some of this is just plain incorrect conclusions.  We know that all engines today can handle Gasoline, so we can put this off to the side for a minute.  We know that E85 is at least 85% Ethyl Alcohol during the summer months.  This, of course, is the target of the skeptics.  100% Ethyl Alcohol is not corrosive.  It only becomes corrosive when more than 1% water is added to the mix.  The result when water is added and heated is an acid that is very corrosive and very bad for internal engine components.  The requirements for stations to sell E85 are quite strict and are all designed to keep water out of the mix.  Last night, I pulled a 20 oz sample from the station I use to fillup.  If more than 1% water is present in the mix, phase separation of the gasoline and alcohol will occur.  No separation occurred so the fuel was safe for my truck.  I then went further.  A clear plastic water bottle works well for this test.  When I got back home, I added water a little at a time to the mix.  Sure enough separation began to occur.  When my test was done, I could easily see the three components in the bottle.  Ethyl Alcohol; however, is a superb cleaner.  As such, an engine and fuel delivery system consistently exposed to Gasoline will have many deposits.  So, when switching an engine over to E85, care must be taken.  The people at Xcelplus sell additives to prepare your vehicle.  I do not know if this is an absolute requirement; but, better safe than sorry. 

 

Next,  Let's talk about what today's engine need to run properly.  Yes, you can simply adjust the air/fuel ratios to achieve stoichiometry with E85 just as you can with gasoline.  Unfortunately, larger injectors along with an Air/Fuel Controller, as a point solution, may not completely satisfy your requirements and No, adjusting the air/fuel will not have any impact on ignition timing.  In fact, no ignition timing adjustment is required unless increased engine performance is part of the focus.  We have to remember all of the newer ODBII vehicles have programming of the PCM to control the adjustments your engine makes.  Many of these vehicles have either a mechanically controlled fuel pump or an electronically controlled returnless fuel delivery system.  Simply increasing the pulse widths at the fuel injectors either with the flextek or larger injectors does nothing to increase the flow rate from the fuel pump to the fuel injectors.  This gap is never seen unless wide open throttle is commanded or in the case of trucks and suvs, the engine is put under load by towing something.  In these instances, the only solutions are to either reprogram the fuel pump or in mechanical systems replace the fuel pump with a higher flowing fuel pump. 

 

I hope this helps.

 

 

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