25% more power in a mighyboy? solution: Avgas

[Jermaine]

aparently u can run avgas in a mightyboy and it will give it 25& more power!!!! i havnt tried it yet i have to get my hands on some avgas but a bloke that ownes one and races it said that it will so yeah

[Josh]

AVGAS is not rocket-fuel. In simplest terms, it is very high octane petrol.

This means that it is very stable and can be compressed a lot before it begins to detonate and cause engine damage. Engines that are able to run higher compression ratios are more efficient and generate more power.

Running a high-octane fuel like that your in MightyBoy's F5A engine however, is not going to net you significant power increases without serious internal work being performed on the engine. It will in fact run worse if you run in on AVGAS with it tuned to manufacturer's specs. As it stands there is no point in running an F5A on fuel with a higher octane rating than 95RON, let alone AVGAS which can have an octane rating as high as 130RON.

[Munchskinman]

what would rocket fuel or a huge percent of ethanol do to your cars performance?

[Josh]

Let's put that one to rest, dude...

[eDave]

Isn't Avgas leaded anyway?

[mowog]

It is leaded but as the Mighty Boys don't have a cat it does no harm. In fact the exhaust from unleaded running without a cat are far far more harmful to the environment and people than leaded petrol is. The damage unleaded does is very carefully covered up by the authorities and petrol companies but there is an argument that unleaded petrol, even when treated through a cat, is more harmful than leaded ever was.

[Josh]

How is that possible? One could argue that it is due to the stabilisers added modern regular unleaded to boost its octane rating - but lead was added as a lubricant and cushion, not to alter the octane rating of early fuels as I understood... so leaded fuels would still harbour the same stabilisers to generate an appropriate octane rating anyway...

Care to elaborate a little more on these conspiracy theories? I'm interested...

[evilgidget]

Very early (ie 1920's/1930's) blends of fuel were unleaded and had an octane rating of 'about' 70RON. It was decided by the manufacturers that the 20,000 mile engine rebuilds that needed doing was bad, so lead was added to help slow valve head recession. It also had the side effect of raising the RON level of that crappy old unleaded to approx 90RON.

Now, when the time came to remove that awful lead from the fuel that was killing baby foxes and making the world's orphan's cry, they had to somehow raise the octane raiting of the fuel, so all the world's cars wouldn't suddenly ping themselves to death. So, they added *stuff* that did the job very well, but produced even more poisons to kill the baby foxes. This poison did however have the benefit that it was able to be converted to less poisonous poisons by a CAT converter.

Problem with that is, if the fuel mixture is too lean, too many poisons get through. If the mixture is too rich, the CAT dies early, letting the poisons through. If the CAT isn't warmed up, the poisons get through. The CAT dies normally through use in about 4 years anyway, so poisons get through. Is there a pattern developing here?

Nothing like 25 times more carbon monoxide, gaseous cyanide, etc etc etc just from having to run unleaded eh? Just as well that CAT burns them up eh?

No, wait...

[Santos]

When the oil companies went leaded it was primarily to be able to run lower grade fuel, it was cleverly disguised by using a different octane rating (why the states has two) To say that cars needed rebuilding on account of fuel would be a bit misleading. After all the manufacturing technology was no where near what it was say in the 60's after lead was already in place anyway. Pistons where not as snug, head and deck not as flat, bolts not as strong, etc etc... after all cars back then didn't rev to improve reliability .

If the fuel was bad it wasn't because it was unleaded, the refinery process was cruder and shortages were met with numerous substitutes that gunked up thesyste quicker.

As for cars having higher emmisions then leaded after the cat dies then it would depend on the unleaded fuel, i proudly run e10 98ron in my suzuki 1.3L, it would be different to say Vortex or Optimax. The motor had an excellent service history so it's running strong, i hope to blueprint it for performance, hopefully so it runs on a different sort of dual fuel petrol/ pure alcohol (legalise moonshine at home)

Everytime i read an article on a a car they are more efficient, the extract more power from less fuel. to give you an example i read about an 1.6l engine that gave 80kws power, at first i thought "bah, a cultus motor is 1.3l and 86kw and that was back in the 80's " then it occured to me that newer motor used 2l less every 100km's more despite displacing 300cc a revolution (i think it had more torque then the cultus too) So emmision wise it's probably pumping out less poisons (like say whatever percentage of 2l less equiv to a cultus)

[Jermaine]

um so in english plz! is it any good to run or will it damage the engine?

[ToranaGuy]

I've read that the Mighty Boy shouldn't be run on ethanol blended fuels.

It's got to be either the steel tank, rubbers in the fuel system or the plastic in the carby getting attacked by the ethanol. Mind you, i've tried the 94RON " green " E10 unleaded from united that's availible down my way in the MB, and it does run a bit nicer on it over regular cats p*ss unleaded, and it's usually 4cents cheaper a lrt as well.

I can only see the issue of the petrol tank and the rubbers in the fuel system being long term usage, probably 10yrs, but the carby i don't know about.

I've tried optimax, votex and a couple of other 98ish RON premiums in the MB, didn't make any noticable differance for the extra $$ per fill, but the E10 did and it was cheaper. Must be due to Mb's compression. Mind you, if i tuned the engine to suit a higher octane fuel it would probably run better on it.

Cheers

ToranaGuy

[Munchskinman]

my boy runs better on 98 than 91 or 95... smoother too...

[mowog]

Have a look at WWW.SMASA.COM.AU/DOCUMENTS/ARCHIVES/2000/UNLEADED FUEL.HTML

[Hewball]

http://www.smasa.com.au/documents/archi ... _fuel.html
i think this is what you were after

[Josh]

my boy runs better on 98 than 91 or 95... smoother too...

It runs smoother because of the slower burn rate than 91 - and you're actually generating less power.