E85 Tuning and general info thread.

[jerrah]

Do you HAVE to have bigger injectors, or would the standard NA6 ones work fine? I'm about to order my MS DIY PNP and was wondering if I'd need to get new injectors at that time?

Gslender I have some Supra 305's that I'm no longer using since I upgraded to RC 550's. Cleaned and flow tested. I 'think' you can run 305's in a pinch on the stock ECU but it will run rich. They're plug and play with the stock injector loom.

[jerrah]

With an LC1 you can either tell it your running e85, and it will display stoich as 9.7, or you can just leave it and remember that your aiming for 13:1 afr rather than 12:1 afr like you would on petrol

If stoich is 9.7 vs 14.7:1 why would you be aiming for a leaner mix at WOT on e85?

[NitroDann]

You would NEVER just run 305s and e85 on the stock ecu, just incase anyone reading gets that idea.

Jerrah I leave the LC1 displaying petrol values, where a lambda of 1 is displayed as 14.7.

As the LC1 has no idea what fuel is in it, it will display stoich as 14.7 if its running on vodka and you havent told it your not running on petrol.
The wideband simply measures lambda. So it will measure stoich simply as a lambda of 1.
It then has been told your running on regular petrol so at a lambda of 1 it will display 14.7(because a lambda of one-stoich- is 14.7:1 afr on petrol) regardless of what fuel is in the car, if its been set to 'petrol mode'.
I leave it in 'petrol mode', as I learned to tune on petrol so Ive got the whole,' 14.7 is stoich, idle it at 15-16, slight acceleration at 13-13.5, wide open throttle at 12-12.5' notion set in cement when i tune.

Relearning all of these values is hard to do, and confusing, so if you leave the LC1 displaying petrol values, the only difference is everything should be about half a point leaner, with full power rich about a full point leaner.

If I set the LC1 to 'e85 mode' Id have to remember 9.7 is stoich, idle at 10, cruise at 11, or is it 11.5... I cant remember, so thats why I leave it displaying a petrol value. Remembering that the LC1 has no idea what the air fuel ratio is, it simply measures lambda and then tell you afr, based on what fuel type youve told it.
Most will learn on petrol, so will find the rule of 'half a point leaner and a full point at wide open throttle' easier to remember than a whole new set of values.

I hope that wasnt too confusing.

Dann

[jerrah]

You would NEVER just run 305s and e85 on the stock ecu, just incase anyone reading gets that idea.

Oh I didn't mean that. Just 305's on petrol will idle and 'run'. But Gslender is building a DIYPNP and 305's would be appropriate in that case. I wouldn't go experimenting with e85 without a LC1 handy.

Reason I was questioning your AFR numbers was I would assume e85 would be richer across the MAP than petrol, but you seemed to be suggesting richer at idle and leaner at WOT. i.e. I know you know what you're talking about but I think you may have said 13:1 WOT on e85 when you meant 12:1 on E85 and 13:1 on petrol?

I leave my LC1 on petrol too regardless of fuel.

[NitroDann]

Grr, i wish I could edit.

Ill break it down as ive obviously done a poor job of explaining.

Stoichiometric means perfect blend without leaving either waste air or fuel.

A lambda of 1 represents stoichiometric.

Oxygen sensors only measure lambda.

To display Air Fuel Ratio, like an LC1 does, it simply calculates the afr based on the lambda its reading and the air fuel ratio of the fuel you have told it your running.

A lambda of 1 on petrol represents an air fuel ratio of 14.7:1, and on E85 a lambda of 1 represents an air fuel ratio of 9.7:1.

When using an LC1 to tune, with the LC1 in petrol mode, it will display what it reads as a lambda of 1, as an air fuel ratio of 14.7:1. This is regardless of the fuel. If you run nitromethane with an AFR of 3.5:1, and its running stoichiometric, the LC1 will read a lambda of 1 and display an AFR of 14.7 (simply because you have told it the fuel is petrol).

If you set it to E85 mode it will display what it reads as a lambda of 1 as 9.7:1AFR, as that represents the air fuel ratio of E85 at a lambda of 1.

Rather than have the LC1 -display- to me that a lambda of 1 is 9.7 when tuning e85, I leave it displaying a lambda of 1 as 14.7.
The true afr will be 9.7 at stoich but the LC1 doesnt know this, it simply measures lambda, regardless of fuel.
I could change it to display 9.7 for lambda reading of 1. But I choose to leave it displaying 14.7 for a lambda reading of 1. This is because if I do so all I need to do is tune using the same numbers as petrol, but half a point leaner.

Eg,
At full power on petrol we aim for 12:1, or a lambda of 0.85.
At full power on E85 we aim for 8:1, or a lambda of 0.9.
Leaving the LC1 to think that we are on petrol, it will display that lambda of 0.9 as 13:1, even though in truth the afr is 8:1.
The LC1 only knows what the lambda is.
I leave it displaying incorrect petrol values of Lambda 1=14.7AFR because I find it easier to tune using the petrol targets I have already commited to memory, but keeping it half a point leaner across the board, because E85 runs better with a slightly leaner lambda.

I could tell it to display using AFRs of 9.7 = lambda 1 but then id have to remember all new tuning targets rather than just use petrol ones but half a point leaner.

Dann

[jerrah]

Dann,

As a base how much timing did you find you had to run to idle on e85? Did you ever run e85 on the stock cams?

[NitroDann]

E85 - lc1 cheat sheet.

This is a cheat sheet intended to allow people to use my method of tuning e85.
Learn to tune on petrol first, use the megasquirt base map or whatever base map you have and tune on petrol.

For petrol

Use these figures at these load points, all load points are in kpa. All are basic setting that will be safe on all engines, these arent to be taken as gospel, they are just a good start.
these are for power and economy, not for passing emissions.

First do a free air calibration of your wideband sensor like the manual says, then make sure its set to petrol (gasoline).


Stoichiometric will display as 14.7:1 air fuel ratio

Idle at or near stoich if you can, you may need to run heaps of idle advance to do this, say 18 or 20 degrees. Aim for a smooth idle with near stoich reading at the rpm you want. Stuff tuning idle for the lowest KPA values.

Cruise at around 16.5:1- you can cruise leaner than this without misfires but... you will use 5% less fuel and make 10% less power, resulting in WORSE fuel economy. Cruise is usually defined at 40-65kpa in an na/nb.

Tune overrun as lean as you can (overrun is all kpa values lower than what the car idles at, ie when engine breaking the car will pull a vacuum lower than at idle). You may actually ADD fuel here, its bad for emissions and economy but youll get wicked overrun flames etc. You may find that using a full fuel cut will result in a slight jerk as you transition back into the idle fuel cells, this is due to sudden addition of fuel. if you cant avoid this, turn overrun fuel cut off and just reduce the fuel values there as low as you can go while retaining a nice smooth transition into and out of overrun.

Mild acceleration, such as when you notice your 5kmh under and you just slowly cruise back up to the limit. Tune this to an AFR of 14:1-14.7:1, around or just richer than stoich. These kpa values will be somewhere near 70kpa.

You want to taper the 70kpa values from 14:1 down to 13:1 as you approach 100kpa.

100kpa is ambient air pressure so if your car is naturally aspirated this is where you stop.

if your turbo you need to taper the AFRs down to 12.5:1 by 140kpa and perhaps a little closer to 12:1 by 200kpa (200kpa is a bar of boost, 14psi)

This will get you well on your way with petrol.

When your ready to swap over to E85

THIS METHOD USES THE LC1 SET ON PETROL MODE NOT E85 MODE, IT -WILL- DISPLAY AIR FUEL RATIOS THAT ARE WRONG FOR E85, READ THE ABOVE POST IT EXPLAINS WHY, THIS METHOD WILL BE MUCH EASIER FOR PEOPLE WHOVE TUNED ONCE OR TWICE ON PETROL TO CHANGE OVER TO E85 RATHER THAN CHANGING THE LC1s SETTING AND RELEARNING ALL THE E85 AFR VALUES.

When you do the swap to E85 put a 5 litre jerry can of it in the car and lap the block of the servo literally until it runs dry and stalls. Fill up with the e85 and before you start the car change the base map values.
Either change req fuel on a megasquirt, or on other computers you can do other things like change total injector trim, or you can tell the ecu that your injectors are smaller than they are, or you could just increase every fuel value on the fuel table.
The change is by 30% to get you started, right across the board, from overrun to full power.
If you ecu asks what sized injectors you have you can tell it they are 30% smaller, therefore the car will increase the fuel values by 30%, or increase the whole map by 30% or you can increase REQ FUEL on a megasquirt by 30%.

Increase all timing across the board by 3 degrees as a good start.

Try to start the car.

If it wont start (it really should on the remnants of petrol in the lines) you need to increase the cranking pulsewith by a millisecond at a time until it starts. This will need to be tuned just as you had to do in the past on petrol. But for now this should give you a car that can be reliably started, even if its a bitch for now.

Now sit and tune the idle back to stoich, again your tuning for 14.7 just like on petrol as the LC1 is still set on petrol mode, so its displaying stoich as 14.7.
Get it to idle nice playing with fuel and timing and idle valve duty cycle just as before on petrol.

Now gently drive it to the servo watching the AFRs the whole time. Stop the car immediately and increase the fuel in the bins that it runs lean in, if any.

Fill her up with E85.

Give it a couple of gentle revs through out the range slowly increasing revs. We do this just to check if theres a huge rich or lean spot on the map. So dont stomp on it, gently slowly increase revs and just blip it slowly using slowly increasing throttle application so we can get a good look at the low mid and high kpa sections of the map at all rpm.
See any silly rich or lean areas? change them.
Now drive it to a long straight hill.

Tune using all the same values as petrol but half a point leaner when not idling. Still idle at 14.7 but cruise at 16.5.

60kpa acceleration at 14.5 odd AFR rather than 14.

100kpa at 13.4-13.5 rather than 13.

This is because e85 runs nice a little leaner than petrol. Keep in mind that its never at 14.7:1, its just that we have kept the LC1 displayed values set to petrol to make tuning easier on our memories.

Congrats you have a car that runs on biofuel.

Now tune spark as before.

Dann

[NitroDann]

Dann,

As a base how much timing did you find you had to run to idle on e85? Did you ever run e85 on the stock cams?

Well Ive left the ecu and crank angle sensor all set up for 10 degrees static timing. But my idle setting are about 18 degrees I think now, maybe 16. I do have compression and cams though and I never ran it without them, so those figures wont necessarily be right for you. Mind you compression will lower timing and E85 will increase it so it may

The megamanual always repeats to tune idle for max vacuum, for me this meant 34 degrees of timing at idle!
With this much timing there is NO way to drop idle below 1200 or so rpm, so it obviously isnt the way to go.

I can manage to have mine idle almost totally smoothly at 1000rpm with my big cams, but honestly, I f*ck my idle so it sounds good and live with the bumper stain I think Ive got it at just the right lumpiness for me but without unwanted attention.

Dann

[spaztikcamel]

nitro you should definantly take a small vid so we can hear what your car sounds like at idle.

I will be all over e85 as soon as its on a pump in ballina.

[jerrah]

http://www.ethanolanswers.com.au/

Wish there was more stations in Brisbane. Wondering if it's worth running it now (and driving out of the way to get it) to encourage Caltex to spread it further.

[Skinny Jim]

hello

digging up an old thread. insomnia got the better of me last night so i was googling around and came across this thread. interesting stuff. are people still running on e85?

You would NEVER just run 305s and e85 on the stock ecu, just incase anyone reading gets that idea.

Oh I didn't mean that. Just 305's on petrol will idle and 'run'. But Gslender is building a DIYPNP and 305's would be appropriate in that case. I wouldn't go experimenting with e85 without a LC1 handy.
.

i don't really understand this... say in a na6 we're looking for 30% over the stock 240 injectors so 305's are pretty close to the 312 we're after. the car will run just fine on the stock ecu in closed loop, coz the ecu really doesn't care what size injectors are in there, it just uses the oxygen sensor to hunt for lambda and adjusts accordingly. in open loop things get a bit more tricky but if your injectors are the appropriate size, then what's the problem? if you're worried about the accuracy of an old sensor, well just chuck a new one in. they're only $50ish and it's a good idea to replace them every few years anyway. get yourself a $20 air/fuel meter to keep an eye on things just in case. you could even "tune" it by adjusting the screw that tensions the spring in the vane afm or better yet use a cheapo fuel only piggyback. actually if you used a piggyback you might not even need to change the injectors in the first place then bump up the timing to 30 or whatever, and sit back and enjoy your cheap horsepower upgrade.

i know it'll never be as good as a full on megasquirt / lc1 wideband setup, but a hell of a lot cheaper and easier to set up, and retains stock driveability.

thoughts?

[Dan]

hello

digging up an old thread. insomnia got the better of me last night so i was googling around and came across this thread. interesting stuff. are people still running on e85?

You would NEVER just run 305s and e85 on the stock ecu, just incase anyone reading gets that idea.

Oh I didn't mean that. Just 305's on petrol will idle and 'run'. But Gslender is building a DIYPNP and 305's would be appropriate in that case. I wouldn't go experimenting with e85 without a LC1 handy.
.

i don't really understand this... say in a na6 we're looking for 30% over the stock 240 injectors so 305's are pretty close to the 312 we're after. the car will run just fine on the stock ecu in closed loop, coz the ecu really doesn't care what size injectors are in there, it just uses the oxygen sensor to hunt for lambda and adjusts accordingly. in open loop things get a bit more tricky but if your injectors are the appropriate size, then what's the problem? if you're worried about the accuracy of an old sensor, well just chuck a new one in. they're only $50ish and it's a good idea to replace them every few years anyway. get yourself a $20 air/fuel meter to keep an eye on things just in case. you could even "tune" it by adjusting the screw that tensions the spring in the vane afm or better yet use a cheapo fuel only piggyback. actually if you used a piggyback you might not even need to change the injectors in the first place then bump up the timing to 30 or whatever, and sit back and enjoy your cheap horsepower upgrade.

i know it'll never be as good as a full on megasquirt / lc1 wideband setup, but a hell of a lot cheaper and easier to set up, and retains stock driveability.

thoughts?

Even if the injectors were the right size and the ECU could compensate I wouldn't trust a 20 year old car to flow at 100% IDC.

If you are going to run E85 buy the tools to do it right.

[Skinny Jim]

IDC ?

[NitroDann]

The fueling and timing requirements for E85 arent static, you cant just add 30% you need to add around 30%.

The stoich is 30% different but the evaporation point and specific heat capacity etc are not.

Dann

[Dan]

IDC ?

Injector Duty Cycle. Basically what I was saying was that I wouldn't trust 20 year old Injectors to flow to 100% of the number they were rated to out of the factory.

I also don't think the ECU will be able to compensate for it properly even if they could flow enough fuel. Dann is right, the amount of fuel you need to add isn't static and Ethanol is also more knock-resistant so figuring out if something is wrong is more difficult too.

Even on my 4 year old Evo I had some teething issues with running E85 using a professional tuner, a full upgraded fuel system (injectors, pump, lines, filter etc...) and a Wideband + Datalogging to monitor it.