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shadowR wrote:

remember boost = pressure in the cylinder = raised compression

And you want to put boost in an already high compression engine

shadowR wrote:

high compression engine has a lower final result than a turbo charger unit as the added airflow from the aspiration results in alot more torque. so theoreticaly you can get your power figures from lower boost levels on smaller turbos. the result will be a faster spooling engine needing less boost.

It still wont be as good as a DET how long do you exprct your engine to last

If it was me I would do the job proply and put in a DET insteed of putting a turbo on a DE. U13 1/2 cuts are very cheap now but hay its your car do what you like

This can be over come by better / more efficeint intercooling to lower the intake temps therefore reducing the tendency to knock. So provided you can stop the engine from rattling itself to death, for the same boost figure (temperature corrected by cooling) the higher static CR engine will make better power.

182Go wrote:

yeah theres only so much intercoolers can do when the cooling medium is ambient air though, maybe a water injection system will provide the knock protection you need in this situation

Author:	shadowR [ Wed Nov 30, 2005 11:38 pm ]
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thanx for the help guys, i wonder how long that guy can hold onto the manifold and turbo for... damn i want it.. thanx for the back up on turboing my de. theres all too many success stories and almost no fuck ups to need question it. the raised compression will result in more performance its fact not fiction. thanx Neb~ ur the kind of inspiration i needed for my car.

Author:	182Go [ Mon Dec 05, 2005 11:55 am ]
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JayS14 wrote: shadowR wrote: remember boost = pressure in the cylinder = raised compression And you want to put boost in an already high compression engine shadowR wrote: high compression engine has a lower final result than a turbo charger unit as the added airflow from the aspiration results in alot more torque. so theoreticaly you can get your power figures from lower boost levels on smaller turbos. the result will be a faster spooling engine needing less boost. It still wont be as good as a DET how long do you exprct your engine to last If it was me I would do the job proply and put in a DET insteed of putting a turbo on a DE. U13 1/2 cuts are very cheap now but hay its your car do what you like This is a double egded sword... Yes raised static compression ratio will yield more power and torque but lets not get confused between cylinder pressure and boost. By increasing static CR you are also increasing cylinder pressure / heat but still have the same vaccuum / boost. Where turboing the NA falls down is the moment you add boost to a higher static CR engine you reach the knock limit of the fuel at a lower boost figure. This can be over come by better / more efficeint intercooling to lower the intake temps therefore reducing the tendency to knock. So provided you can stop the engine from rattling itself to death, for the same boost figure (temperature corrected by cooling) the higher static CR engine will make better power.

Author:	mokompri [ Mon Dec 05, 2005 3:09 pm ]
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182Go wrote: This can be over come by better / more efficeint intercooling to lower the intake temps therefore reducing the tendency to knock. So provided you can stop the engine from rattling itself to death, for the same boost figure (temperature corrected by cooling) the higher static CR engine will make better power. yeah theres only so much intercoolers can do when the cooling medium is ambient air though, maybe a water injection system will provide the knock protection you need in this situation

Author:	182Go [ Mon Dec 05, 2005 5:49 pm ]
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mokompri wrote: 182Go wrote: This can be over come by better / more efficeint intercooling to lower the intake temps therefore reducing the tendency to knock. So provided you can stop the engine from rattling itself to death, for the same boost figure (temperature corrected by cooling) the higher static CR engine will make better power. yeah theres only so much intercoolers can do when the cooling medium is ambient air though, maybe a water injection system will provide the knock protection you need in this situation It all depends if the high compression intake air can be brought down to ambient if it can then they would be on a level playing field. Guess this would depend on the intercooler being able to perform up to the task. I was actually thinking along the lines of one of those cryo units on a good FMIC. I guess if you wanted to run the DE engine or a high comp replacement forge in the DET you could just plan a bigger intercooler to bring it back to the same intake temp...

Author:	mokompri [ Mon Dec 05, 2005 8:24 pm ]
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you could never get it close to ambient on an air to air setup though water injection has secondary effects of 'anti-knock' other then just cooling the intake charge too, the water in the mix reduces the chances of pre-gnition from lowering its flash point i believe

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Author:	Arkhaeon [ Tue Dec 06, 2005 2:15 am ]
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are you saying you add water to your air/fuel?

Author:	too_much_boost [ Tue Dec 06, 2005 6:24 am ]
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Yep, its al old school anti-detonation technique. It was used before conventional intercoolers were common (and so cheap). It is also used on old draw-through systems where an intercooler cannot be used. I used water/metho injection in my 3.3L turbo torana many years back..

Author:	Arkhaeon [ Tue Dec 06, 2005 7:06 am ]
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well there ya go.. I was always under the impression that any water in the cyl = engine go boom

Author:	ZEi250t [ Tue Dec 06, 2005 8:10 am ]
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why do you put metho in it as well? is it to keep the water from staying 'wet' in the cylinder. because this would lead to rust, even tho it would evaporate with the heat.

Author:	too_much_boost [ Tue Dec 06, 2005 8:24 am ]
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Metho has better heat absorption properties. Its nothing to do with corrosion or wetness

Author:	ZEi250t [ Tue Dec 06, 2005 8:33 am ]
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then why use water at all? i suppose the metho would affect the fuel mixture as it is combustable also

Author:	182Go [ Tue Dec 06, 2005 1:27 pm ]
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Yep we definately have to go back to old school for this one. Water by itself has no anti knock properties because it can't be burnt and has no octane rating. But yes it can supress detonation by lowering the air temp below the ping threshold. Over the years a number of different additives were used in conjuction with water. Metho was just one of them. Why add water??? because it's FREE. You can run straight metho but that can be expensive especially when you look how crude some of the water injection systems were back then. Metho does have the added benifit of combustability which will produce power. Methanol was also a popular additives amounst the rev heads. One thing to bare in mind when using water / other... use to much and you can distroy the engine. Remeber you can cut steel with water when you have sufficient quantity and at enough speed. So injecting the right amount to cool the intake charge without consuming valuble space in the cylinder is important. Another benefit of water injection / water vapour systems is that it can reduce carbon build up on valves. Over the years they played with different injection points with some people injecting directly into the compressor housing. Water injection is not limited to turbo cars only, 20 years ago we were using it on high compression (over 10.5:1) NA engines back when super was 98 octane. man that was a trip down memory lane.

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