Volumetric Efficiency.

[SVXRide]

Originally Posted by oab_au

The engine has very good air flow as it is. If at higher boost, or a higher power at the same boost is wanted, the 240* 8mm lift inlet cam will allow the VE to curve off a lot slower at the higher rpms. Supporting the torque to higher rpms.

Personally speaking, when you see how this Stage 3 set up runs, you would need to be brave to want more. It has the potential to take more boost, either with a lower comp ratio, or with boost controller, reducing the boost at lower rpms, and water controlling detonation at higher rpms.

A supercharged engine makes very usable power, right through the rev range, a joy to drive.

Harvey.

Harvey,
Realizing I'm probably setting myself up for a "as soon as Bill gets some flow bench runs done we'll know better" comment, do you think we've actually got a chance of seeing even more "street-friendly" performance with changes to our exhaust cams?
-Bill (whose extra set of stock exhaust cams are still sitting around at Delta Cams...)

[Duckie]

I guess I am one of the few people who just wants more power before even using the current stage 3 setup. I plan on pushing this car as far as it can go while still remaining a reliable and nice daily driver.

[oab_au]

Originally Posted by SVXRide

Harvey,
Realizing I'm probably setting myself up for a "as soon as Bill gets some flow bench runs done we'll know better" comment, do you think we've actually got a chance of seeing even more "street-friendly" performance with changes to our exhaust cams?
-Bill (whose extra set of stock exhaust cams are still sitting around at Delta Cams...)

Bill there does not seem to be any need for changing the exhaust cams, at this time. The Auto does not run to the rpms where the exhaust needs modifying. The lift is adequate and the duration only needs extending for the higher rpms, like 6500 up. There is also the problem that the longer duration will need the exhaust header branches lengthened, to stop the gas pressure from entering the cylinders on the same side.

I know that the header construction is not all that difficulty, but there is a fair chance that the extra VE supplied by the exhaust, may be lost in the process. The exhaust supples about 12% more VE at peak torque, as it is.

The VE curve, that I posted, is of the engine used as an air pump, that is, not running, just being driven. When the engine is firing, and the exhaust is functioning the peak VE at 98% increases to 110 %. We don't want to lose this power in the pursuit of just boasting different cams.

If somebody with a 5/6 speed, that wants to run in the 3500 to 7500 range wants to build the best power. Then the duration of both cams need extending, at the expense of loosing torque below 4000. This will envolve building new longer, header branches, and developing the system to gain the best results.

Harvey.

[SVXRide]

Originally Posted by oab_au

Bill there does not seem to be any need for changing the exhaust cams, at this time. The Auto does not run to the rpms where the exhaust needs modifying. The lift is adequate and the duration only needs extending for the higher rpms, like 6500 up. There is also the problem that the longer duration will need the exhaust header branches lengthened, to stop the gas pressure from entering the cylinders on the same side.

I know that the header construction is not all that difficulty, but there is a fair chance that the extra VE supplied by the exhaust, may be lost in the process. The exhaust supples about 12% more VE at peak torque, as it is.

The VE curve, that I posted, is of the engine used as an air pump, that is, not running, just being driven. When the engine is firing, and the exhaust is functioning the peak VE at 98% increases to 110 %. We don't want to lose this power in the pursuit of just boasting different cams.

If somebody with a 5/6 speed, that wants to run in the 3500 to 7500 range wants to build the best power. Then the duration of both cams need extending, at the expense of loosing torque below 4000. This will envolve building new longer, header branches, and developing the system to gain the best results.

Harvey.

Harvey,
Thanks! I was starting to come to this conclusion....
-Bill