Jump to content
SAU Community

Recommended Posts

To be honest, I never really used flex fuel.

Seems good, in the real world once you're on E85 you don't need 98, as the availability is fine unless you're driving to Mildura etc.

That said, flex isn't very hard. All the ECU needs to know is ethanol % which it turns from 0V to 5V.

Then the ECU takes that input which may be like 2.5V, and applies a certain percentage of a correction map to fuel/timing/boost, relative to the voltage of that input.

That's all there is to it

  • Like 1

To be honest, I never really used flex fuel.

Seems good, in the real world once you're on E85 you don't need 98, as the availability is fine unless you're driving to Mildura etc.

That said, flex isn't very hard. All the ECU needs to know is ethanol % which it turns from 0V to 5V.

Then the ECU takes that input which may be like 2.5V, and applies a certain percentage of a correction map to fuel/timing/boost, relative to the voltage of that input.

That's all there is to it

i regularly drive to brissie.

Then I suggest you get a wideband and flex fuel

Wideband because playing with correction maps is likely going to be needed if you want it perfect. Its quite time intensive and expecting it to be PERFECT from a few hours on a dyno will never be feasible.

There's a lot of "hm, I'm idling at 13.7 AFR when I'd like it to be 14.7 when I am on 72% 98 and 28% E85" goings on

then again, can i justify paying 3k or so to make car flex fuel capable? 800$ for injectors, nistune, 1k +-, sensors and stuff, 1k, scotty intake 300?

i'll still run stock turbo.

Running E85 on stock turbo is really not a cost effective/convienient solution

Technically speaking, all E85 does is removes limitations of less than optimal systems, its not like you're gonna slam 30PSI into a stock turbo with a ton of timing for other explodey reasons...

If you could hit MBT and Peak compressor efficiency from your turbo on 98 without it pinging to death, switching to E85 wouldn't give you more power, I've been told that's why some people see big gains from E85 and some people don't

There's still gains to be made from advancing the timing and taking advantage of 107 octane.

Boost will also come on sooner.

But I think if you're spending that much on upgrades you should at the least get an $800 high flow and get another 60-70rwkw out of it while you're there, sacrifice a bit of response given the factory turbo is responsive and linear enough let alone with E85.

Technically speaking though, advancing timing only increases power to a point, after a point it starts reducing power.

If you're not pinging at that point, on 98 well, you don't need E85. It's possible in some lovely systems to not be pinging at MBT.

Same thing re: Boost pressure.

But in the real world, where we do stuff like add turbos to systems designed for lesser turbos, well, E85 starts becoming cool.

Would be curious to see what happens on a stock system, but you aren't gonna run more than 10psi on it anyway.

I would wager youd gain more powars per dollar by upgrading to a hiflow on 98, vs converting to E85 on a stock turbo.

Running E85 on stock turbo is really not a cost effective/convienient solution

Technically speaking, all E85 does is removes limitations of less than optimal systems, its not like you're gonna slam 30PSI into a stock turbo with a ton of timing for other explodey reasons...

If you could hit MBT and Peak compressor efficiency from your turbo on 98 without it pinging to death, switching to E85 wouldn't give you more power, I've been told that's why some people see big gains from E85 and some people don't

There's still gains to be made from advancing the timing and taking advantage of 107 octane.

Boost will also come on sooner.

But I think if you're spending that much on upgrades you should at the least get an $800 high flow and get another 60-70rwkw out of it while you're there, sacrifice a bit of response given the factory turbo is responsive and linear enough let alone with E85.

so. 4k? LOL.

I'm planning on moving to the country, so there will be winton days on 98 and any tracks in city E85

saves me having to do a run down to MELB with jerry cans to do a tampered day.

Planning on going north?

Guest
This topic is now closed to further replies.



  • Similar Content

  • Latest Posts

    • For once a good news  It needed to be adjusted by that one nut and it is ok  At least something was easy But thank you very much for help. But a small issue is now(gearbox) that when the car is stationary you can hear "clinking" from gearbox so some of the bearing is 100% not that happy... It goes away once you push clutch so it is 100% gearbox. Just if you know...what that bearing could be? It sounding like "spun bearing" but it is louder.
    • Yeah, that's fine**. But the numbers you came up with are just wrong. Try it for yourself. Put in any voltage from the possible range and see what result you get. You get nonsense. ** When I say "fine", I mean, it's still shit. The very simple linear formula (slope & intercept) is shit for a sensor with a non-linear response. This is the curve, from your data above. Look at the CURVE! It's only really linear between about 30 and 90 °C. And if you used only that range to define a curve, it would be great. But you would go more and more wrong as you went to higher temps. And that is why the slope & intercept found when you use 50 and 150 as the end points is so bad halfway between those points. The real curve is a long way below the linear curve which just zips straight between the end points, like this one. You could probably use the same slope and a lower intercept, to move that straight line down, and spread the error out. But you would 5-10°C off in a lot of places. You'd need to say what temperature range you really wanted to be most right - say, 100 to 130, and plop the line closest to teh real curve in that region, which would make it quite wrong down at the lower temperatures. Let me just say that HPTuners are not being realistic in only allowing for a simple linear curve. 
    • I feel I should re-iterate. The above picture is the only option available in the software and the blurb from HP Tuners I quoted earlier is the only way to add data to it and that's the description they offer as to how to figure it out. The only fields available is the blank box after (Input/ ) and the box right before = Output. Those are the only numbers that can be entered.
    • No, your formula is arse backwards. Mine is totally different to yours, and is the one I said was bang on at 50 and 150. I'll put your data into Excel (actually it already is, chart it and fit a linear fit to it, aiming to make it evenly wrong across the whole span. But not now. Other things to do first.
    • God damnit. The only option I actually have in the software is the one that is screenshotted. I am glad that I at least got it right... for those two points. Would it actually change anything if I chose/used 80C and 120C as the two points instead? My brain wants to imagine the formula put into HPtuners would be the same equation, otherwise none of this makes sense to me, unless: 1) The formula you put into VCM Scanner/HPTuners is always linear 2) The two points/input pairs are only arbitrary to choose (as the documentation implies) IF the actual scaling of the sensor is linear. then 3) If the scaling is not linear, the two points you choose matter a great deal, because the formula will draw a line between those two points only.
×
×
  • Create New...