been thinking about this over the last couple days, with turbos what exactly causes detonation? is it the actual pressure caused by the turbo or is it the increased temperature caused by the turbo working the air??

if its the temperature thing then is possible to increase the pressure of the turbo limitlessly provided you could keep temperatures where they should be?

just wondering if i was to get a big intercooler,one of them power gaskets, a water injection system, CO2 cooling for the intercooler and bigger pipes in/out of the intake to keep temperature down and resistance to air down could i push more power out of the turbo??

While you are waiting for an informed answer from one of our experts, bengie, have a read of this very informative article on Engine Basics: Detonation and Pre-Ignition. It's very readable and informative.

You would also need to consider everything downstream of the turbo i.e. the exhaust in the one direction and in the other things like the tip, valves/springs, pistons, con rods, bearings, the crank, the gearbox, the diff, the driveshafts etc etc...

now you mention the exhaust i have just heard form my local dealer and the car is very nearly done, thanks to a new gearbox, prop shaft and clutch slave cylinder but they also said that the bracket on my middle box was rusted off and my rear box "didn't look to clever either" so would i like them to replace them labour free as the were removing them anyway?? but at about

oh and cheers denis, i had a read of that link earlier, very good it was although a little long winded when using a PDA to read it. but still good none the less

Bengie, try Blue Flame www.blueflameperformance.co.uk for a bespoke stystem, you can listen to mine when you collect the suspension. If you need a free stop gap I have a complete std 4x4 system you can have.

I went the sports cat route, if you go full de-cat it will be noisy both inside & outside, you will also then get problems with the check engine light coming on & when this is on the cars computer backs off the performance slightly

still no cure for the cell thingy then??

and cheers for still having the suspension stuart i feel a right **** about this, sorry for the delay but as said i may actually have a car again soon, it'll only be about 3 months without one! :thumbdwn:

just been looking at the blueflame website and i must say it looks good and i have emalied them for some more info but does anyone here have an idea of price for systems on the octavis estate, i have no idea wether its going to be

just been looking at the blueflame website and i must say it looks good and i have emalied them for some more info but does anyone here have an idea of price for systems on the octavis estate, i have no idea wether its going to be

Detonation is caused by both in a way really and another thing on top of that, The higher the boost pressure the hotter the internal temp. So this kinda answers boths parts but you also have to think of fuel quality, the higher the RON (Research Octane Number) value the less likely it is to detonate, but to get the best out of the higher octane you need a knock sensor which monitors the ignition and reports back to the iginition system to tell it to spark earlier or later depending on the grade of fuel.

This maybe wrong but that is the way I understood it.

Dont quote me but......

As I understand it, pre-ignition or detonation is caused by the final peak temperature of the air mixture reached in the cylinder exceeding a critical level. This final temperature is largely determined by the mass of air and its temperature at the start of the compression stroke, the compression ratio, the speed of the compression stroke and to a lesser extent piston/cylinder temperature . More boost from a turbo increases the mass of air (this air is also heats from the exhaust side of the turbo as a side effect). An intercooler cools the charge before it gets into the cylinder but cooling increases the density, hence the mass.

By retarding ignition timing, the peak pressure and peak temperature immediately after ignition, but before TDC can be reduced.

In bad cases, carbon deposits in the head cause hot spots which also trigger preignition. Using a cooler heat range spark plug also avoids preignition from a red hot plug tip. In these cases preignition occurs before the electrical ignition and causes much damage.

Lower RON fuel contains more pentane which is the stuff that preignites most readily.

So cooling may not help without reducing compression ratio.