SlprTeg, you're assuming that a boost wash condition exists in which unburned compressed a/f mixture makes its way out the exhaust valve before the compression stroke. IF such a condition exists, THEN your argument about power being lost due to lower EGT is correct.

However.

Stock VTEC cams do not have enough overlap (unless the phasing is played with via adjustable cam gears) to cause a boost wash under most conditions. Check out this dyno from importreview.com:



If you can't read the type, it's a stock GSR motor with some sort of way-too-big turbo. Look at the jump in power at the VTEC switchover. It's exaggerated a bit here because of the huge turbo but it demonstrates that there's definately not a loss of power when the VTEC lobes kick in.

 

Last I checked, higher density fluids pushed out lower density fluids from the same occupied space. Again, overlap is between the exhaust and intake stroke, lasts very few thousandths of a second, and if a bit of fresh a/f mix makes it into the turbo manifold unburned, who cares? It's still a higher density charge at a lower temperature, sure it won't expand as much as if it were burnt, but volume is relative to heat, so it will expand as it's passing through the turbine. You will not cause lag due to valve overlap, you will cause worse lag if you try to run with very small or zero overlap. 100% efficiency is the goal, not the result.

Explain to me how there's going to be an extreme pressure difference from a boosted intake charge entering the cylinder at the same time a boosted, burnt exhaust charge is exiting? Extreme temperature difference I'll give you, the pressure I won't, even in NA engines, gases attempt to disperse to gain an equilibrium pressure once released, the hotter exhaust gasses will always be at a higher pressure, until the exhaust valve opens. It really doesn't matter what the pressure of the incoming charge is, you are trying to deal more with port designs and vortices than merely the interaction of gases with heat and pressures.

 

Ok then...I have a GSR and I want to make about 265 whp with a turbo....what are the steps in accomplishing this??? And what kind of setup should I at??

:thumbup: Oh yeah and some of ya'll really know ya'lls $hit Thanks :thumbup:

 

I meant extreme temperature, my bad. Liek the weather shizzat :0) Extreme pressures dont cause vortexs h:

Thx for catchin that typo

 

You said it was a big turbo, , so maybe it didnt spool til vtec kicked in j/k.

 

Drag3 kit, TurboXS manual boost controller, 370cc/min injectors, A'PEXi V-AFC, Thermal R&D 3" exhaust, and a couple hours of dyno tuning. That should get you off to a good start.