<<<these kits will knock you back into your seat, believe me! With the combination of high compression and an efficient turbo system these systems spool so quickly turbo lag is almost non existent. >>>

I read this on Wyatt's website, but I though it was better to have lower compression with turbo charged engines? Anyone shed some light on this subject?

Thanks,
Brad
98 gs

I still want to know what compression is? and what are these numbers 8:8:3 and so on?

LAST EDITED ON 13-Jul-01 AT 01:15 AM (PST)

When boosting, its preferable to be in the 8's:1. Our pistons are flat on top which gives us a 9.6:1 compression stock. If you buy pistons from hahn they will be forged 8.8:1. The tops of the pistons will not be flat but cupped like a bowl. Although the bowl's dip is very slight, it helps lower the compression which in turn, allows you to boost higher and not 'knock'. Knocking happens because as you compress air, the temperature of the air increases. The temperature may increase enough to ignite the fuel before the spark plug fires. Cars with turbochargers often need to run on higher octane fuel to avoid knock. If the boost pressure is really high, the compression ratio of the engine may have to be reduced to avoid knocking. Engines that run high boost levels in HIGH compression atmospheres risk 'more' the integrety of rings and gaskets than lower compression engines.
During the compression stroke, the piston starts from the bottom of the block and goes clear to the top of the block compressing the charged air and fuel. When the air is compressed, it heats up; and when the air heats up, it expands. Part of the pressure increase from a turbocharger is the result of heating the air before it goes into the engine. In order to increase the power of the engine, the objective is to get more air molecules into the cylinder, not necessarily more air pressure.

good question, i decided to research that one.

Here is a site that has a good explanation.


http://www.dragnbreath.com/dragnbreath/TechNotesA/TN2HowtoFig.html