leescoobynut

just wanted to know what deting was, and what i would benifit from a uprated fuel reulater,i have a uprated fuel pump,as it was recomended as my old one packed up,i was told that imports should have a uprated fuel pump and regulater to stop detonation,was not sure what detonation was as i aint been on the scooby scene that long came anyone explain this to me, ..cheers

Budgie

iTrader: (4)

you need to ask frayz

budgie

frayz

iTrader: (7)

Just typing a reply mate gimmie 2 secs

Budgie

iTrader: (4)

frayz

iTrader: (7)

Detting or detonation, pinging, knock, knocking, pinking its all the same thing.

Basically its premature ignition of the air/fuel mixture inside the combustion chamber. This means the air/fuel mixture ignites on its own without the aid of a spark plug before its due to ignite.

This is caused to excess heat in the cylinders and can be caused by a variety of things. These can be, lean condition, excess charge inlet tempratures, too much ignition advance, poor combustion chamber design etc etc.

Any one of these things is causing the cylinder tempratures to become too hot and igniting the mixture before its required.



If you can imagine the 4 stroke cycle happens in this order.



1, INTAKE STROKE

Inlet valve opens, piston moves down and a fresh chrage of air and fuel is drawn into the cylinder. The piston will now be at the bottom of its stroke BDC (Bottom Dead Centre)

2. COMPRESSION STROKE

Inlet valve closes and the fresh charge of fuel and air is compressed as the piston comes back up to the top of the cylinder this is known as TDC (Top Dead Centre)

3. POWER STROKE

The spark plug ignites the compressed charge. The energy of the "exploding" mixture pushes the piston down with tremendous force. This force is enough to keep the cycle continuing repeatedly once started.The piston is now back at BDC.

4. EXHAUST STROKE

The exhaust valve opens and the used, waste exhaust gases are forced out of cylinder by the piston now returning to TDC. The exhaust valve will now shut, the inlet will open and the whole process starts again.

Now you have an idea as to whats actually going on inside your engine you will realise the incredible forces that are acting on the comonents and also the speed at which this is happeneing.

So at 4000RPM, this process is happening 1000 times a minute in each of the 4 cylinders. Or 4000 times in total, thats 66.6 times a second!!

Now if we were to have detonation occuring the process wil be disrupted. This is because the mixture is being ignited before the piston has fully returned to TDC on the compression stroke.

Now you can imagine the force of the piston coming up at speed and the force of the unwanted premature ignition trying to force it back down again at the same time... something has to give.

This shockloading is phenominal and can easily blow holes in pistons, destroy bearings and bend/snap rods.

The cause of det you are refering to with regards to the fuel pump is that the fuel pump cannot keep up the fuel demand of the engine.

This causes a lean condition which results in excess heat in the cylinders. This heat can then lead to possible detonation and premature ignition of the air/fuel mixture.

I hope that helps answer your questions.

Please feel free to ask if i havenot been clear enough

Frayz

Nate

iTrader: (2)

...... Whoa there Frayz

frayz

iTrader: (7)

Was it understandable though, thats what i need to know?

leescoobynut

cheers that was alot more than i was expecting but not complaining,made alot of sense, and now have more of an idea whats going on,as to high pressure fuel pump to stop it running lean,mine at the moment i think is running rich as its using alot of fuel,also smell it out the back plus some nice pops coming out the back,some nice flames also ive been told,but never the less dont think it should be doing that some how..cheers for your help.

frayz

iTrader: (7)

Welcome Lee,

Slightly rich is much much better than slightly lean. If you have any concerns id take it to a specialist just for a quick det and AFR check.

Worth its weight in gold for the onwards peace of mind

leescoobynut

does that cost much cause founds are abit low at the min,also what does afr mean ,..cheers

frayz

iTrader: (7)

AFR = Air Fuel Ratio

Im not sure on exact cost of a check up but id guess it will take no more than an hour so say approx a hours rate.

leescoobynut

thanks for all your help will have alook for the cost of the check up ..cheers again..

frayz

iTrader: (7)

No problem

SirFozzalot

frayz

iTrader: (7)

You made sense of that lot Fozzie?

Jimladfatboy

Nate

iTrader: (2)

Frayz,

Easily understandable

But one question, should this be moved to 'Lets ask Frayzzzzz) ?

frayz

iTrader: (7)

Lol @ the "Ask frayz" thread...

Can be moved if need be mate. Lol!