E10 vs E85 petrol type

[cat007]

Hi all,


Just wondering - E85 (at least from United) uses 15% premium (98) unleaded and has an octane of around 105-107.
But looks like E10 only uses regular unleaded for it's petrol content and has an octane of only 95?


So am I right in assuming that for a car tuned with flex fuel for 98 and E85, I shouldn't use E10, even though it has the magical E in the name? I should really only stick to E85 or 98 or a mix of both?

[ryeman]

My 2 turbos run happily and economically on E10 but I’d think the E85 would be needed for the anti knock tuned ones which are tuned for min tailpipe emissions.


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[nstg8a]

Correct. If it’s tuned for e85 and 98 I’d stay clear of e10 unless in an emergency. If you have to run it don’t load it up.


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[mick taylor]

Originally Posted by cat007

Hi all,


Just wondering - E85 (at least from United) uses 15% premium (98) unleaded and has an octane of around 105-107.
But looks like E10 only uses regular unleaded for it's petrol content and has an octane of only 95?


So am I right in assuming that for a car tuned with flex fuel for 98 and E85, I shouldn't use E10, even though it has the magical E in the name? I should really only stick to E85 or 98 or a mix of both?

We have 91 octane E10 as well man and 94 E10, the problem here in QLD at least do not always display the octane rating, that's insane ! I could blow my carby fed bike up if I did not know that fact.

I filled up the wife's Aurion with BP 91 E10 and the difference between running 94 E10 is a huge power difference, just as 91 unleaded is to 95 unleaded is huge.
Some Caltex is E10 is 91 octane and some is 94 E10, all BP is 91 E10 that I have seen, but Shell E10 I do not know.

[Dr Terry]

The OP used the term "flex fuel". If this is the case then the EFI system should have an fuel octane sensor built into it.

If it does, then the car should run on anything from 91 to E85, depending on the tune program. The programmer may not have allowed for the use of lower octane fuel, so really he is the only person who could answer that question.

If it doesn't have an octane sensor, I can't see how it could accept E85 & 98 or whatever.

Dr Terry

[ratter]

there is no fuel octane sensor

[Mechan1k]

Originally Posted by ratter

there is no fuel octane sensor

I read up on it ... and it just reads Ethanol Content by the looks of it within the Flex fuel sensor

[BENT_8]

I wouldn't use any of it, my Son started using E10 when he bought his S2 VE 3.0l SIDI which is E85 compatible and it started having starting trouble, diagnosed as fuel pump fault, was going to cost a fortune to fix so I suggested using normal 91and the problem went away and ran fine for months, accidently put it in again and sure enough started playing up again.
Considering the number of VE fuel pump issues you hear about, I wouldn't be surprised if there's nothing wrong with the pump and it's actually the E fuel causing it.

[stevanford]

Originally Posted by cat007

Hi all,


Just wondering - E85 (at least from United) uses 15% premium (98) unleaded and has an octane of around 105-107.
But looks like E10 only uses regular unleaded for it's petrol content and has an octane of only 95?


So am I right in assuming that for a car tuned with flex fuel for 98 and E85, I shouldn't use E10, even though it has the magical E in the name? I should really only stick to E85 or 98 or a mix of both?

E85 is 85% ethanol hence the higher octane rating.
E10 is only 10% ethanol. If your car is tuned for any mixture between 98 and E85 then do not run E10 under any circumstances.

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[Dr Terry]

Originally Posted by ratter

there is no fuel octane sensor

How did the tuner tune for 98 & E85 without fitting a flex-fuel sensor ?

The difference in fuel density (read volume) alone would be enough to require 2 different maps.

Dr Terry

[cat007]

Originally Posted by Dr Terry

How did the tuner tune for 98 & E85 without fitting a flex-fuel sensor ?

The difference in fuel density (read volume) alone would be enough to require 2 different maps.

Dr Terry

As in my first post, car is tuned with a flex fuel sensor on 98 and E85 (also has PCMTec's multi tune).


Further reading shows that PUMP E10, while having 10% ethanol, has a much lower octane rating than an mix of 98 and E85 as E85 is mixed with 15% 98 where-as PUMP E10 uses 90% of 'regular' (read: 91 octane) unleaded.


So in short - if your car has flex fuel and is tuned to run on 98 octane or E85 (~107 octane) then you cannot just use PUMP E10 as this only has a 95 octane. You could drive on it, if you had to, but nurse it.

[EFFalcon]

Originally Posted by Dr Terry

How did the tuner tune for 98 & E85 without fitting a flex-fuel sensor ?

The difference in fuel density (read volume) alone would be enough to require 2 different maps.

Dr Terry

I think his point was more that it measures ethanol content, not octane.

[Dr Terry]

Originally Posted by cat007

As in my first post, car is tuned with a flex fuel sensor on 98 and E85 (also has PCMTec's multi tune).


Further reading shows that PUMP E10, while having 10% ethanol, has a much lower octane rating than an mix of 98 and E85 as E85 is mixed with 15% 98 where-as PUMP E10 uses 90% of 'regular' (read: 91 octane) unleaded.


So in short - if your car has flex fuel and is tuned to run on 98 octane or E85 (~107 octane) then you cannot just use PUMP E10 as this only has a 95 octane. You could drive on it, if you had to, but nurse it.

I don't quite get it.

There isn't a huge difference in the octane rating or fuel volume between E10 (95) & 98, however there is quite a big difference between 98 & E85 (which according to my info is 105 RON). If the guy can tune 2 maps for those 2 fuels, why can't another fuel which is only 3 RON less, be used.

At most Sydney servos they quote E10 as 94 RON, so as not to confuse it with 95 Premium.

Holden's flex-fuel tuning caters for 91, 94/95 (E10), 95 Prem, 98 Prem & E85 using the same flex-fuel sensor.

Dr Terry

[cat007]

Originally Posted by Dr Terry

I don't quite get it.

There isn't a huge difference in the octane rating or fuel volume between E10 (95) & 98, however there is quite a big difference between 98 & E85 (which according to my info is 105 RON). If the guy can tune 2 maps for those 2 fuels, why can't another fuel which is only 3 RON less, be used.

At most Sydney servos they quote E10 as 94 RON, so as not to confuse it with 95 Premium.

Holden's flex-fuel tuning caters for 91, 94/95 (E10), 95 Prem, 98 Prem & E85 using the same flex-fuel sensor.

Dr Terry

I assume the problem comes that even on wastegate pressure on E85 I'm making 270rwkw and on 98 that's probably around 220-230rwkw. There's not much you can do to detune it to run on 91 other than pull timing, but that's a waste of time. If I wanted a slow car that runs on 91 I'd just buy a Holden.

[ratter]

Originally Posted by Dr Terry

How did the tuner tune for 98 & E85 without fitting a flex-fuel sensor ?

The difference in fuel density (read volume) alone would be enough to require 2 different maps.

Dr Terry

as mentioned already, a ethanol sensor is used to see the ethanol content of the fuel being used and the fuel, spark and boost maps can be automatically adjusted to how ever the tuner sees fit.
We have done quite a few now including my own car and the system works great and gives a great deal of tuneability to the car and all without the owner having to stress what fuel is in the car.

I think you may be confusing octane rating and ethanol percentage

[Dr Terry]

Originally Posted by ratter

as mentioned already, a ethanol sensor is used to see the ethanol content of the fuel being used and the fuel, spark and boost maps can be automatically adjusted to how ever the tuner sees fit.
We have done quite a few now including my own car and the system works great and gives a great deal of tuneability to the car and all without the owner having to stress what fuel is in the car.

I think you may be confusing octane rating and ethanol percentage

So you're saying that the flex-fuel sensor is only sensing the ethanol percentage & not the RON of the fuel.

How then does it work in the factory Holden SIDI set-up where it senses whether you are using 91 or 98 premium & adjusts the fuel & timing maps according when these 2 fuels have 0% ethanol.

I know it's the very same sensor, I sell these at work to the various dyno shops in the area.

Dr Terry

[cat007]

Originally Posted by Dr Terry

So you're saying that the flex-fuel sensor is only sensing the ethanol percentage & not the RON of the fuel.



How then does it work in the factory Holden SIDI set-up where it senses whether you are using 91 or 98 premium & adjusts the fuel & timing maps according when these 2 fuels have 0% ethanol.



I know it's the very same sensor, I sell these at work to the various dyno shops in the area.



Dr Terry

It won't use that sensor to detect RON and change timing. That's not what a flex fuel sensor is for or able to do.

I reckon those cars just use a knock sensor to detect and change ignition timing. Assumes 98 on start up until it detects knock early on then changes ignition map to a 95 map, then 91 etc....

That's my guess.

They won't actually be detecting the RON of the fuel.

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[ratter]

Cat is correct.
There is no such thing as a RON sensor, there is an electronic hand held sensor, but they are not reliable enough to trust for engine control

[jpd80]

Originally Posted by Dr Terry

So you're saying that the flex-fuel sensor is only sensing the ethanol percentage & not the RON of the fuel.

How then does it work in the factory Holden SIDI set-up where it senses whether you are using 91 or 98 premium & adjusts the fuel & timing maps according when these 2 fuels have 0% ethanol.

I know it's the very same sensor, I sell these at work to the various dyno shops in the area.

Dr Terry

With petrol, I think it's a case of the ECU advancing timing until it detects knock and then backs off
that knock level is long before we hear it so is pretty safe for machines to measure and adjust
without any damage being done.

No doubt Flex fuel vehicles do this but I suspect they also detect the level of ethanol present
in the fuel so that the air fuel mixture is optimised to the ethanol blend present.

I think the issue with E10 versus RON 98 is not actually the RON number
but more the difference in MON as a measure of detonation resistance under load
E10 has Mon of about 83, not much above regular non blended fuel where
RON 98 has a MON of around 88, much safer for boosted engines.

I do wonder about using E10 as a sub for vehicles that require RON 95,
it might work but it could also equally lean the mixture enough to expose
detonation prone areas in the fuel map...

Ethanol when blended actually changes its RON /MON in a non-linear way from pure state
Its RON can be anywhere between 120 and 135 and the MON 100-106,
the ethanol itself in higher amounts has a dampening effect on detonation
and is generally why E85 can produce wicked amounts of power.....

[arronm]

E85 rules. Makes great power. Barra turbo flex conversions and tunes are the way to go now.

[ratter]

Many modern vehicles can adjust for e10 while in closed loop fuel control and their fuel maps are rich enough so the e10 lean factor is not an issue, but many still recommend the minimum octane rating is still met

[Dr Terry]

Fair enough, that's quite a good explanation.

Dr Terry

[jpd80]

Originally Posted by ratter

Many modern vehicles can adjust for e10 while in closed loop fuel control and their fuel maps are rich enough so the e10 lean factor is not an issue, but many still recommend the minimum octane rating is still met

The issue with lean out is not light throttle closed loop, it more of full throttle enrichment.
Unblended fuel requires around 12.7 to 1,where E10 needs more like 12.3 to 1 so a modern
engine might behave as if running at a leaner 13 to 1 on unblended petrol. Yes, it's a small
change but as I suggested earlier, it also comes with a slightly increased chance of detonation .
Not a certainty by any means bit something to consider.

[ratter]

The fuel maps are rich enough in open loop to be safe

[mick taylor]

Originally Posted by ratter

The fuel maps are rich enough in open loop to be safe

When running 91 unleaded and filling up on E10 what happens when I start the car directly after filling up is that she starts hunting, the tacho needle is bouncing up and down 500 rpm or so, until she does this about 6 times until she works out what the go is.
So she must know the difference of the fuel and adjust to it directly.
2015 model car.
So it must adjust in closed loop mode.

[ratter]

The fuel trims will correct in closed loop fuel control, but there is a small delay after starting before closed loop becomes active

[Bossxr8]

Originally Posted by jpd80

With petrol, I think it's a case of the ECU advancing timing until it detects knock and then backs off
that knock level is long before we hear it so is pretty safe for machines to measure and adjust
without any damage being done.

Pretty much spot on. It will continually add timing till it detects slight knock, then pulls the timing back. Cycle continually repeats.

[ratter]

The falcon ecu only retards spark, it will add it back if knock is not detected

[You Yangs]

Originally Posted by BENT_8

I wouldn't use any of it, my Son started using E10 when he bought his S2 VE 3.0l SIDI which is E85 compatible and it started having starting trouble, diagnosed as fuel pump fault, was going to cost a fortune to fix so I suggested using normal 91and the problem went away and ran fine for months, accidently put it in again and sure enough started playing up again.
Considering the number of VE fuel pump issues you hear about, I wouldn't be surprised if there's nothing wrong with the pump and it's actually the E fuel causing it.

This is exactly why people who use E fuel for the first time never use it again.
If you have never put E fuel in say a 5 year old car and then you do, the Ethanol has just mixed with whatever amount of water you have in your tank.
Yes that's right every fuel tank will over time accumulate moisture.
And Boom!!!! rough running, hard starting.....Oh must be the E fuel?
I'm never using that again!!!!!

[arronm]

Thats why its good to use E10. Sucks up the water.