higher compression - retard timing?

[ryan lang]

I did a quick one last night based on rough figures and came back with 8.3:1

[EPnick22]

Ryan was that with the 1.9 gasket or 1.4? and why on earth you on here at 5.40am?! haha

Edited September 21, 2013 by EPnick22

[AdamB]

My mistake, Tim's right with his numbers. I was using a method which I got taught at college, dunno why I was taught that way though lol.

The Athena has a diameter of 75.5mm I believe and the Cometic is 76mm.

I take it then the knock sensor is only there as a fail safe, for example when a fuel pump is failing or an injector is blown out? As its not there for show so I suspect its doing something.

[TBDevelopments]

its ok mate my numbers were really rough as well, as didn't know the full information but it'll get him close enough.

the stock knock sensor can read a noise level based on its feedback, like when you connect the power fc to it it'll show a numerical figure for background noise and knock. But the stock ecu doesn't do much until it fails and then goes into a safemode. The experience i've had with these is the ecu will obviously have a figure for safemode activation, i've seen this trigger a few times and the sensor be ok but 9/10 the sensor fails, engine goes into safemode and protects itself.

In toyotas eyes just like fuel cut it'll only ever happen if there is something critically wrong with the engine and its setup, so the fact it blows £150 worth of sensor everytime doesn't even cross there mind as like you said its an last stand fail safe. But when tuning if not setup correctly or run right on the limit then you hit this problem more often than not.

Its a shame you can'get something like an emanage or even the power fc like i run and get it mapped as at 9.0:1 it would make a much nicer car to drive on a 200bhp road going setup. Much more responsive. better fuel economy and just more efficient all round. It would also make more power and torque per PSI of boost compared to the lower compression examples.

Again quoting the 3sgte tuning i've done over the years we only ever drop the 8.2:1 which is stock CR for a starlet until we get near the 600bhp range on pump fuel. So it always surprised me how low the glanza was out the box, Almost reminds me of the old ford tuners where as soon as you put a bigger turbo on you'd rip all the compression out of the thing to make 400bhp (7.5:1) and have it all topend and low down and midrange torque would be terrible. But with the new setups and the way tuning has evolved you really don't need to do that anymore until you start going silly. and 200bhp is only a light fettle as far as I'm concerned.

But if you can't go that route then the 1.7 or 1.9mm range of gaskets should do you fine. I'd aim more for the 1.6/7 personally to account for the unknown numbers in the calculations. Not sure on the sizes available to you.

right going to crawl back into my hole, lol message me if you guys need anything else.

Tim

TB Developments