Standard grey motor fuel consumption

EK283 · Post by **EK283** » Sat Dec 15, 2007 8:52 am

Super versus unleaded.

Super fuels in the good old days contained lead and a good octane rating.
Older cars would run with allmost any compression ratio as high as 11 to 1. and not suffer from pinging.
Todays fuels have no lead and burn at much higher temperatures causing very fast wear on valve seats that are not hardened. The lead would cushion the valve against the seat and would help burn at lower temperatures. The increased combustion temperature with unleaded causes pre ignition or detonation of the fuel before the engine reaches it optimum firing point (hence pinging).
New cars have knock sensors and adjust the timing to suit the fuel explosion in the combustion chamber.
The older cars with lower compression can use unleaded but require an addative to replace the lead to avoid valve recession.
Octane boost also helps and if you can get the mixture right you will save fuel because it will burn more efficiently.
Of course driving style loading and even tyres will become part of the equation.

Regards Greg

rosco · Post by **rosco** » Sat Dec 15, 2007 9:32 am

Just about off to work - you've escaped another big one.......
Thanks Greg for you information.
I have fitted unleaded seats to my head - or the head specialist did (and to the engine head - not mine!).
He tells me it will live for a thousand years............ and if I plan to keep it long time......... love you long time Hangley........... to continue to use the additive - I use Flashlube - but exactly to the recommended dose.
He tells me a lot of trouble comes back when people become "kind" to their engine. Do not over-dose - it builds up and leaves deposits in the head, inlet manifold and chamber parts. Better to slightly under dose than over.
He tells me that it is not possible to get unleaded valves - only the seat inserts or replacements. For that reason alone he suggests using the additive.
I use Optimax, Ultimate, or Vortex but on figures I am averaging, it would appear at present Ultimate is giving very, very marginal higher figures ........ I realise this depends greatly on all variables. and as members of my Victorian club would point out very quickly, my bus doesn't get out much -perhaps resulting in evaporation.................

On the question of VSR - the explanation given to me was that with all current unleaded fuels, the valve seat actually welds (micro - micro scopically) with the valve itself, when they part - the seat is of softer materieal than the valve and this eventually causes the seat to deteriorate under the continual pounding and parting from the valve under its spring - hence the seat recedes.
If you run solid lifters or in the case of a grey motor - be careful - this will reduce your rocker clearances - it is probably not enough to do damage if you keep them regularly adjusted, but be aware of it. I don't believe there is issue if you are using a VSR prevention additive.

The advantage of the additive is to provide a "powder coating or insulation" on combustion and this coats the valve and seat in its exhaust through the port..............but don't overdose in the belief it will make them last any longer.

just my thoughts for today............

frats,
Rosco

munro · Post by **munro** » Sat Dec 15, 2007 1:06 pm

i've got a LC torana that gets 4.4km/litre and it doesn't mater if i'm flogging it or driving miss daisy. mind you thats running a full house 202 and supra 5speed.
i was running a 3.3blue at one stage and getting between 10+12km/litre but it was no fun

cheers tom

mrs ratbox · Post by **mrs ratbox** » Sat Dec 15, 2007 9:13 pm

oldnek what's yor explanation for the van makes no difference what i run that on either

a mate who races big motor bikes and is a mechanic who did alot of fuel research reckons unless yor constantly sitting on 3,000 rpm or more there is no need for hardened seats or additives but it doesn't hert
additives (not octane booster) also drop the octane rating of the fuel

rosco · Post by **rosco** » Sun Dec 16, 2007 7:59 am

Hi Ratbox,
thanks for your information.
I can make some sense of this - to my limited knowledge it would appear that we are referring to the heat of the exhaust?
I am of the opinion that when I tow, and have to use maximum power over an extended period - I would want to have the comfort of knowing that the valve/seat are receiving some insulative support to that great heat - which must exists even below 3K rpm.......... I would like to hear more on this, it has re-opened my mind on the subject.........
frats,
Rosco

karsten · Post by **karsten** » Sun Dec 16, 2007 9:41 am

driving big bangers ,i have found that cause they have a pyrometer that when the revs drop under load exaust temps go up and if you go back a gear to increase revs or just increase revs in the same gear that the exaust temp drops im thinking due to increased air flow and water pump speed that air flow helps to cool by takeing heat away more quickly its a hard one to guess a temp reading test would be available on a dyno maybe someone mite know

Miss Piggy · Post by **Miss Piggy** » Sun Jan 20, 2008 11:16 am

Hi all,

I drove from Brisbane to Newcastle in a single day. Used 140L of fuel (around 12.5L/100km). She sat on 50-60 the whole way. 3spd Manual.

Exhaust is a single 2" with extractors.

Just used 98RON fuel and Flash Lube.

Around town and it works out at a steady 20L/100km.

Craig · Post by **Craig** » Sun Jan 20, 2008 11:35 am

Welcome to the forum miss piggy mine runs around 8km/lt on the highway with the tripples not sure about the city

Miss Piggy · Post by **Miss Piggy** » Sun Jan 20, 2008 11:42 am

Thanks craig.

Forgot to mention, standard stromberg with aftermarket air filter. Nothing flash. 8km/L seems average for highway by the looks.

On a side note, the car needed every seal replaced after the drive. It seems that the previous owner rebuilt it and thought that roofing selastic would be an ideal replacement for gasket goop.

FBeing · Post by **FBeing** » Sun Feb 08, 2009 8:44 pm

Hey guys

Just put a reconditioned engine in my EK, has hardened valve seats.

What is the best fuel to run it on?

Premium?

And is there any need to put additive in anymore, I am guessing those days are over.

Stu

Craig · Post by **Craig** » Sun Feb 08, 2009 9:27 pm

No need for aditives with the new seats

I run both of mine on Premium but thats a personal preferance as some of the covinence stores that sell fuel sell crap steer clear of the ethonol shite (remember when you got service at a service station cant even buy a plug lead at most of them these days but you can buy condoms and breakie cerial dont eat them together kids)

Just of topic for a sec got a new work car this week a Diesel &*#@ Transit open the fuel door and it says unleaded only

F wits

mrs ratbox · Post by **mrs ratbox** » Sun Feb 08, 2009 10:02 pm

got told a little something, don't know how true it is and it's not really relavent to FB/EK's, a mate has a mechanical work shop they've had a spate of catalytic convertor probs and were told apparently the E10 stuff burns alot hotter and is causing the porcelain in the convertors to melt

i think i've said it before, but i run all types of various fuels in my various cars everything from mild red 6 to carbied and injected V8 and an ecotech V6 and it has made absolutly no difference to consumption or performance

Cal · Post by **Cal** » Sun Feb 08, 2009 10:15 pm

I've heard of people having all sorts of expensive trouble caused by using E10 in cars that aren't suitable for it. I've also heard that it's not to friendly with valve stem seals.........

I sometimes use it in my VE company car and find it does drink a little more with it