E85Forum.com

nosocks · Joined: 28 Feb 2010 Posts: 2

Hey all, first post here. Looking to run "poor man's racegas"

I have a custom vehicle, a few actually.

But I'd like to focus on this motor:
In a nutshell, an J35 honda (3.5 minivan motor) with a turbo on it (laugh at the minivan part but these puppies rip!).

Now I understand you need to bump up the fuel supply about 40-50% to compensate for the lower BTU rating as well as the richer AIR/Fuel ratio required of the fuel.

Well I've found an injector that is factory honda from a different model that does fit with a 42% larger peak flow rate.

Now I can't find an overall flow chart for the thing, but is it a safe bet that this thing flows 40%-ish over consistently across the spectrum?

Would this keep me from needing to remap the computer or will I need to bump the timing at whatnot as well? Is it just the rich or lean factor that is important or are timing changes critical?

Is there a plug in kit that would work well with the turbo factored in?

The stock ECU and Stock programming is running and has for about 200 hours of HARD use, so I know the computer can figure out the boost, just not sure if the new fuel and injectors will throw it for a loop.

Last but not least, just how sensitive is the aluminum thing? I mean this stuff isn't eating aluminum heads alive from what I understand...or have I not heard the bad news?
The fuel lines are braided stainless but should I be in a panic searching for that lone aluminum fitting? Whatever the heck that might be?

Lotsa questions I know, but I'm new Laughing

Thanks

Alcohol · Joined: 17 Apr 2007 Posts: 634 Location: Central Wisconsin

I will address part of your questions and leave the rest for Hotrod and others who are better versed;

"Now I understand you need to bump up the fuel supply about 40-50% to compensate for the lower BTU rating as well as the richer AIR/Fuel ratio required of the fuel. "

You are really correcting for A/F rather than BTU. The BTU content is only approx 27% less for E85. For A/F I know the carb guys will generally give it 35-42% more at WOT. E85 will tolerate rich better than gas and some say that just a bit rich adds a bit more torque. I do not know Hondas, nor the injector you have found. I do know Hotrod (Larry) on this site and NASOIC) intially only went to larger injectors on his turbo Subie and let the ECU do the rest. This approach may not add enough fuel for really great cold temp cold starts like further tuning or an FFV has but seems very safe and easy. If memory serves me Hotrod only added injector size by about 30% in his daily driver and the ECU makes up the rest by LTFT- this allows him to limp slightly rich on gasoline if the need ever arises. I am not sure if his ECU has "learn function" for open loop to keep him at stoich at WOT.

Dig thru old threads by "Honda Ghandi", Hotrod, GT Labs, and others for more answers or perhaps soon others will join in.

"Last but not least, just how sensitive is the aluminum thing? I mean this stuff isn't eating aluminum heads alive from what I understand...or have I not heard the bad news?
The fuel lines are braided stainless but should I be in a panic searching for that lone aluminum fitting? Whatever the heck that might be? "

Aluminum- actually I have not seen any issues with aluminum in my retail fuel pumps, my non-FFVs running mid-blends, fuel tankers hauling ethanol, or anywhere else. I also have not seen folks who are really "in the know" (not the anti-ethanol types who have all sorts of trouble with everything Razz

) that have reported sreious issues. That said however- be aware that the concern may come at fittings where dissimilar metals or "plastic" insert exist. Be aware that there is always potential for something to not like ethanol because the fuel system was built to the gasoline side of the elastomer chart. Frankly if you study an elastomer chart you will find gasoline and it's components are far more restrictive than the requirements for ethanol. Still there are a couple of types that are ok for gas and not the best for ethanol. As far as the metals go- many of the aluminum concerns would come more from the Brazilian style hydrous ethanol vs the dry annhydrous ethanol we use here which includes corrosion inhibitors and must be PH balanced.

nosocks · Joined: 28 Feb 2010 Posts: 2

Gotcha.

Sounds kinda plug and play?

I only heard of problems with anodized or otherwise sealed fuel rails and tanks corroding and tainting the fuel supply.

I understand what I am correcting with regard to A/F ratio. The point of the drill here is that the BTU shortfall and the A/F ratio requirements meet or exceed the results of a gasoline motor. Similar to why drag cars use nitro, low BTU, lower A/F ratio needed=big power.

So fundamentally, I'm on board, but thank you for the explanation.

What are those little plug-in computers or "flex fuel" devices? I don't plan on switching off fuels, the car need a particular octane and I hope that E85 is a long-term solution. So I have no need to "flex"... just to fuel...

If I can get away with sizing up the injectors appropriately and making sure all containers are safe, I should be fine yeah?

Alcohol · Joined: 17 Apr 2007 Posts: 634 Location: Central Wisconsin

The plug and play modules that I am familiar with (Flex-tech, Brazilian kits, and such) simply add pulse time or a second pulse to the ECU's signal. If you are already adding fuel via the larger injector then I think this would not be productive and thus force the ECU to pull fuel trims back. The only concern I have with a flat recommendation of these kits are that if the injector is too small and duty cycle is exceeded or there are other limitations such as fuel pump delivery then at least in a performance application one could have issues. For this reason plus lack of easy access to the injector connections I have not put a "kit" on my '04 Saab Aero 2T. I did talk with a Saab tech in a performance shop who assurred me the injectors and pump are large enough for E85 and compatible but a ECU flash for mine was not possible because of the type of ECU version it has- I have not had time to verify this elsewhere so I've taken the conservative approach for now. I run E20-E30 instead at least until the warranty period is up- this keeps my ECU happy, fuel trims below CEL threshold, and performance as good or better than premium. Even fuel economy is no different from E20-E27 to E0 Premium and cost per mile is far far less than with premium.

If one is going to use annodized coatings with E85- it would be best to use hard annodized.

I did have a friend who was using E85 straight in his unmodified junkers that were his daily drivers for his carpentry business. The only issue he had was limited to one vehicle and was serious- the seal on his injectors happened to be of the wrong type and he suddenly smelled alcohol. There were leaking on his manifold Shocked

He went to the parts store and bought the same seal as is on FFV's and he was fine for pocket change. Understand these were $100 cars Laughing

While having the wrong seal is rare- one must pay attention if you do not know the material up front.

murphinator · Joined: 08 Jan 2010 Posts: 93

like you I am here to learn in advance of experimenting with e85.

I have also considered the effect of upping injector sizing on a vehicle the same amount as the needed fueling increase - basically scaling the injectors to the stoich of the fuel being used.

Since I also fiddle with pcm tuning there are generally several areas in your tune that would need to be supplied with the proper characterization data for the injectors above & beyond just sizing such as:

Offset vs. Volts vs. VAC
Flow Rate vs. KPA
Short Pulse Limit
Short Pulse Adder
Min Injector Pulse

^ these are examples for GM based vehicles , I would guess your honda has similar characterization under different names.

also all injectors flow the amount they are marketed at a specific pressure , typically your vehicle will be providing a different fuel pressure than the one you get the injectors from so if your vehicle provides less pressure the injector flow rate will go down , if it provides more pressure than the delivered fuel will be greater than the rated size

I do understand your desire to simplify and it may work well for you since others have done it just realize any decent tuner wouldnt consider it "tuned" it would be more of a "hack" < speaking 3rd person here - my own tuning skill is not yet to that point so I pay attention to hack methods as well as "proper" methods Embarassed

OK above was long winded but I wanted to give you some food for thought

my input would be if you can at least verify AFR's with a wideband 02 sensor to ensure you are on the richer end of the afr and not the leaner where going wide open throttle could be disasterous then it would be worth experimenting , if you cant verify rich or lean your rolling the dice
_________________
PB's 1/4 mi 12.209, 117.75 trap ,1/8 mi 7.76 ,93.99 trap , 1.949 short time 4.53 0-60

I tune with HP Tuners software

hotrod · Joined: 19 Apr 2005 Posts: 872 Location: Colorado

Yes my ecu has learning (primarily on the closed loop side), open loop needs to be handled by the scaling of the injectors.

In my experience (Subaru WRX) increasing injector size by 30% was almost perfect for my car. If you need to tweak the mixture a bit, an adjustable fuel pressure regulator works quite well over small increments (+/- 5% or so).

Given how you describe the car, (+42% increase) will likely be a bit too rich, for max power but will give descent cold starts in all but the coldest weather.

If I were you I would go with those injectors and an adjustable fuel pressure regulator. That gives you lots of flexibility, very cheap and you don't need to screw around with the ECU.

Don't worry about the aluminum unless you live in a near tropical environment (hot and damp). It only seems to be a problem in very humid and hot climates. I have never seen any real problems in this regard.

The folks running carburetors seem to like to run richer (near +40% range) but all the electronic engine management folks I know end up near +30% fuel flow volume to get good performance/drivability.

Larry