Fuel - What do you use?

[TD]

It was 4000km old and unmolested, and compared to other cars with similar km also unmolested, which were run within an hour of each other on the same dyno. It wasn't a purely scientific experiment, but near enough for the purposes of this discussion.

The only difference between other stock vehicles and mine was the fuel, which from a scientific perspective definitely does back up what the race guys would have experienced if their testing was controlled similarly.

[rd415]

I've been thinking about this octane business and extra performance - technically the car is tuned to the octane and therefore a higher octane will only produce a lower power output. Modern computer electronics "self learn" from the sensor inputs, but even then it doesn't happen instantly.

There are plenty of bonifide cases to prove the point - one was the Bathurst 12 hour and an EVO driven by one Eric Bana. It is pretty well documented that he was very slow in practice, erasing the memory fom the computer and going out again and thrashing the EVO put his times up near the front. There are plenty of other recorded cases to prove this.

If you look at the actual technicality of the fuel the octane is it's anti-knock value which is actually the time period it takes the fuel to burn. The knock is caused by the fuel prematurely burning by either compression or a mechanical fault. The timing in an engine is set up so that maximum pressure occurs in the cylinder around 18 degrees after top dead centre. The fast the rpm the sooner the burning has to commence. If you use your common sense you can clearly see that a higher octane fuel burns much faster so therefore the ignition requires to be advanced considerably to finish burning at 18 degrees ATDC. Even modern computers take time to learn this advance, they won't do it instantly because the computer has to read every sensor to ensure correctness. This includes things like turning the Air Conditioning off & on, steering from full lock to lock, brakes, WOT (wide open throttle) sppeed ane temp sensors etc. All the inputs have to be correct to alter advance curve, let alone altering the amount of advance.

The answer and conclusion is that higher octane fuel WILL NOT increase performance without other modifications, the fact is that in most cases it actually reduces performance as the fuel doesn't finish burning until after the piston has gone on power stroke and therefore lowers the combustion pressure and power output.

Sorry for being a bit long-winded but I have tried to explain the mechanics of the fuel burn - I just hope it is easy enough to understand.

Footnote:-
1. Detonation is caused by the fuel igniting under temperature and compression, two flame fronts collide (one from heat and other from normal spark ignition - usual result is a hole in the piston (instant)

2. Pre-ignition is caused by something other than the spark plug igniting the fuel - pinking (commonly called pinging) - usual result of continued pinging is a hole in piston, but this time the piston melts, unlike detonation which pops a clean hole through piston.

[projectrracing]

NOT TRUE - hoses & seals made of rubber YES, but rubber has not been used in automotive components for years - just another well told fib to "dumb down" the general public.

NOT TRUE ALSO - ethanol has nothing to do with rubber hoses and seals.

the ethanol actually corrodes certain types of metals used in older fuel lines, and it is this corrosion that drifts through your fuel systems, slowly killing them in time.

if someone is to change their car to run on E85, then yes the whole fuel system will need to be replaced/converted to suitable metal materials.

[Yeldarb]

I've been thinking about this octane business and extra performance - technically the car is tuned to the octane and therefore a higher octane will only produce a lower power output. Modern computer electronics "self learn" from the sensor inputs, but even then it doesn't happen instantly.

There are plenty of bonifide cases to prove the point - one was the Bathurst 12 hour and an EVO driven by one Eric Bana. It is pretty well documented that he was very slow in practice, erasing the memory fom the computer and going out again and thrashing the EVO put his times up near the front. There are plenty of other recorded cases to prove this.

If you look at the actual technicality of the fuel the octane is it's anti-knock value which is actually the time period it takes the fuel to burn. The knock is caused by the fuel prematurely burning by either compression or a mechanical fault. The timing in an engine is set up so that maximum pressure occurs in the cylinder around 18 degrees after top dead centre. The fast the rpm the sooner the burning has to commence. If you use your common sense you can clearly see that a higher octane fuel burns much faster so therefore the ignition requires to be advanced considerably to finish burning at 18 degrees ATDC. Even modern computers take time to learn this advance, they won't do it instantly because the computer has to read every sensor to ensure correctness. This includes things like turning the Air Conditioning off & on, steering from full lock to lock, brakes, WOT (wide open throttle) sppeed ane temp sensors etc. All the inputs have to be correct to alter advance curve, let alone altering the amount of advance.

The answer and conclusion is that higher octane fuel WILL NOT increase performance without other modifications, the fact is that in most cases it actually reduces performance as the fuel doesn't finish burning until after the piston has gone on power stroke and therefore lowers the combustion pressure and power output.

Sorry for being a bit long-winded but I have tried to explain the mechanics of the fuel burn - I just hope it is easy enough to understand.

Footnote:-
1. Detonation is caused by the fuel igniting under temperature and compression, two flame fronts collide (one from heat and other from normal spark ignition - usual result is a hole in the piston (instant)

2. Pre-ignition is caused by something other than the spark plug igniting the fuel - pinking (commonly called pinging) - usual result of continued pinging is a hole in piston, but this time the piston melts, unlike detonation which pops a clean hole through piston.

Hmmm. So if a car was tuned for E85, taking into account the higher octane burn, therefore advancing the timing, wouldn't it produce more power? The link above to Wiki suggests as much.

[rd415]

NOT TRUE ALSO - ethanol has nothing to do with rubber hoses and seals.

the ethanol actually corrodes certain types of metals used in older fuel lines, and it is this corrosion that drifts through your fuel systems, slowly killing them in time.

if someone is to change their car to run on E85, then yes the whole fuel system will need to be replaced/converted to suitable metal materials.

Where is the evidence - sounds like another wives tale to me - another case of "dumbing down the general public" - It is a common misconception that ethanol damages/corodes rubber hoses. - If you believe Wiki your doing well. It is a common thought also that ethanol attracts water - water corodes metal etc. The plastic fuel tanks fitted to modern cars have trouble coroding and the fuel systems are sealed to the atmosphere (ADR rule from the 70's) so therefore there should be no water able to get into the fuel system. Unless of course you believe in that removing the emmission control systems improves performance, like so many misguided people.

As far as advancing the timing - Higher octane faster burning - less initial advance required - a much different advance curve needs to be plotted.

[Wardski]

NOT TRUE ALSO - ethanol has nothing to do with rubber hoses and seals.

um.............. ??

[projectrracing]

Where is the evidence - sounds like another wives tale to me - another case of "dumbing down the general public" - It is a common misconception that ethanol damages/corodes rubber hoses. - If you believe Wiki your doing well. It is a common thought also that ethanol attracts water - water corodes metal etc. The plastic fuel tanks fitted to modern cars have trouble coroding and the fuel systems are sealed to the atmosphere (ADR rule from the 70's) so therefore there should be no water able to get into the fuel system. Unless of course you believe in that removing the emmission control systems improves performance, like so many misguided people.

As far as advancing the timing - Higher octane faster burning - less initial advance required - a much different advance curve needs to be plotted.

i'm a bit unsure if you quoted the correct post. cos you are talking about stuff i have not mentioned.

p.s. don't ask for evidence without actually giving any yourself.

COMPATIBLE FUEL SYSTEM COMPONENTS: Because ethanol contains oxygen, it can form corrosive agents. Any water that enters the system can promote the formation of formic acid. Although this process takes a significant amount of time before damage occurs, the tank, pump, and lines should be either stainless steel or coated with a plastic material that is ethanol-compatible. All natural rubber parts that could be in contact with ethanol must also be replaced with synthetic and other materials. These are all readily available from manufacturers of racing carburetors and racing fuel system components. In some cases it may be desirable to modify the carburetor so that it can handle the required increased liquid fuel flow when converting from a gasoline application.When considering fuel pump compatibility, it must also be understood that gasoline is an insulator but ethanol does conduct electricity. This should not be an issue for race cars, as they nearly always have a pump that is mounted outside of the tank. However, the pump must be internally ethanol/methanol compatible and must be able to keep up with the increased fuel delivery rates. For information on mechanical pumps, you will have to contact the manufacturer to be sure the pump you plan to run is alcohol/ethanol compatible.

---

for those interested in E85, try this link:- Ethanol Performance Australia

[rd415]

I have already given evidence and links in prior posts in this topic.

I quoted you because of your comment on "ethanol actually corodes certain types of metals" which I answered with researched facts.

"Ethanol Performance Australia can supply you with a E85 conversion system that works with almost any vehicle on the road today" quote from your link that doesn't mention corrosion. PLUS you have backed up my research with your comments on natural rubber etc.

[Wardski]

We seem to be going round in circles...

Just a side note, the formation of "formic acid" is more prevalent when you've gone on holidays and not using the car for 2-3 weeks... Changes in the weather is enough to get the condensation going in the tank, so, technically speaking, so long as you're using your pride n joy all the time, you've got no problems regardless of what sort of hoses & gaskets you've got.

I guess from that inclination, best to have a full tank of 98 prior to going away on holidays for a few weeks, then add a fuel cleaner (one that says it reduces condensation in the tank) to the top of it once you're back from holidays. If you're off for longer than 2-3 weeks (say 6 weeks) then top up with an octane booster/cleaner all in one

[rd415]

Yep - round and round in circles

Agree - full tank and sealed to atmosphere as all modern cars are there is no formation of acid

But it's a great discussion just the same -

it never ceases to amaze me how the written word can be interpretated so different so often

[Yeldarb]

Hey guys, I decided to give CT a call today about E85 after reading some experiences from the XR6 Turbo owners club..

http://www.fordxr6turbo.com/forum/to...ence-with-e85/

Quote from the initial post:

Hi guys,

I have been requested by a few members now on my thoughts and experience with this fuel so I thought id do a small write up which might help out fellow colleagues..

IMHO, if anyone is thinking of going down the path of using E85 I would strongly recommend to get the conversion done properly from the beginning as this will work out cheaper in the long run and save alot of unwanted hassles for the owner and tuner. Some of the bits required for a proper conversion are bigger fuel lines, compatible fuel filter (earls as I mentioned before), surge tank, twin 044 pumps, fuel pressure regulator, dual feed rail, 1000cc injectors and a one way check valve to avoid starting issues...


PROS: Heaps of gains in power went from 329rwkw to 404rwkw, could have gained heaps more if I had a bigger turbo.
Smoothness at idle and while driving is like factory.
Its extremely good for the enviroment inc my exhaust tip.
Hardly produces any carbon dioxide meaning my engine internals stay clean resulting in crystal clear looking engine oil.
Cheap to fill up @ $1.04 a litre. For once I can use my shopping vouchers to get an extra 4c off a litre meaning I pay a $1 a litre which is damn good value for this fuel.

CONS:

Hardware wise dont mind the sound of the twin 044 pumps but it can get quite annoying in due course especially when driven in and out of your driving as it echoes like hell and getting strange looks from the neighbours
Worsened fuel economy. As expected Ethanol burns quicker than petrol meaning I now get an ave of 332km, sometimes 380 as opposed to 480km with 100ron which isnt as bad as I first thought.


Overall, im happy with the conversion and thouroughly recommend E85 for ppl thinking of going down this path. Performance wise its unreal, pulls harder and lasts longer than a 12yr old! Even the flamin fuel smells nice, lucky I didnt mistake it with white wine..lol
On a serious note, if your one of those guys (tightasses) who's always worried about bad fuel economy than simply stay away from it as a full tank will not last a week if driven as your daily. Im lucky I dont live too far awawy from the bowser but for those who do, well you'll just have to wait your turn. Sorry...

So far, its all good from my end and I hope for those who go down this path thourougly enjoy this experiecne as it has brought a big smile to me amd my pride and joy.


Knowing me, I bet I've missed something but meh that's my 2 cents on E85.

(You need to be a member to read the post)...

Ok, this guy has gone all out. But further along in the thread there are members who haven't gone as far and have had reasonable power gains.

So I called CT and spoke to Lachlan. To very briefly summarize there are perforamce gains to be had by tuning our cars to E85. Problem is that you need 30% more fuel to get those gains. With the GENII there isn't yet available the flash to the ECU (we're sruck with the XEDE) to tell it to do so. Also, the direct injection seems to be a problem as well. So from the CT tune perspective, I'm stuffed. But for GENI owners, there might be something in this as they can use the Flash method.

If you interested in fuel ecomony, this is the wrong conversation for you. I'd say you'd be lucky to get 350 out of a tank...This tune is about power.

I wonder about the Hypersport duvalackies that TallDan and the like have purchased? I wonder if they could self tune?

Sadly my nearest E85 station is a Caltex at Macgregor, about a 15 min drive just for fuel.

Having a look around I found this company in Sydney, Powertune Australia, and they did a DUAL TUNE (98RON & E85) on an EVO with limited mods.

Their results:
EVO stock: 170kw atw 21Psi
EVO with Tune:
98RON: 202.2kw atw
E85: 242.2 kw atw

...that's like race fuel...amazing!!

YouTube - Powertune Tech Talk #1 EVO E85 Dual map Tuning.mp4

But he did go for 1000cc injectors and larger fuel pump...

Anyway, it looks like it's out of the question for my car, but there seem to be real possibilities there for those looking at beefing up thier fuel delivery system.

As always I'm no expert, so please correct me on any of my rantings here!!!

Brad

[Wardski]

Nah, still wouldnt do it

Theres some talk on Rexnet as well, and same result - bigger fuel pump, new rails, and much bigger injectors... Not worth the trouble, especially if you go west of brisbane and the best fuel you can find is diesel and 91 (if you're on a long trip and run short), and currently theres only around 20 fuel stations Australia wide selling E85.

[Chuckie Cheese]

Bugger me, looks like I get to join the exclusive RON 95 club. Seeing as my knowledge of cars is pretty fail I pretty much took the dealers words to heart as well as the manual' and cap rating to use 95. Generally been using Shell Premium but in the off chance that I'm struggling for time I'll fill up at the closest vendor, which is usually a Caltex or Peak, both of which I use 95. I don't particularly trash my MPS6 around nor have I used 98 in it so I couldn't really tell if it was actually hampering my car, but since I've had Paris, she's been doing around 570-580 before the fuel light engages.

Suppose I could give 98 a go, what's the worst it could do? ( Explosion )

[Wardski]

Suppose I could give 98 a go, what's the worst it could do? ( Explosion )

Cleaner better burn, slightly better fuel econ, better performance, cleaner motor (if you're using BP ultimate with their cleaners)

[Chuckie Cheese]

A shame that there's no Shell V-Power in WA, would've worked well with the corp. card. Ah well, BP Ultimate it is then I suppose, although what about Vortex 98? Heard some rumors about a shitty octane, true or just a rumor?

[rogwick]

A shame that there's no Shell V-Power in WA, would've worked well with the corp. card. Ah well, BP Ultimate it is then I suppose, although what about Vortex 98? Heard some rumors about a shitty octane, true or just a rumor?

I used be a BP ultimate man mate, I know use Caltex Vortex. It's cheaper and I actually go further on it than BP, performance seems the same. Personally I think BP is overpriced most of the time

[Chuckie Cheese]

Amen to that mate, Vortex is generally cheaper than most of the other brands so I'm gonna go with that.

Cheers buddy!

[ash460]

OK just filled up today. Last tank was BP Ultimate. I did 635km and filled up with 51 litres. This was on my trip out to Tamworth and my fair share of flying overtaking moves.

8.03 l per 100km. Not too bad.

[Logan]

Not to bad that's impressive, I barely get 400k's when I am filling up on 98. Must have been quite a bit of freeway/steady cruising.


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[Macca]

Bp 98