SR20DE head flow numbers.

[JMalapetsa@aol.com]

In a message dated 12/20/2002 4:49:19 PM Eastern Standard Time,
NismoDriver@aol.com writes:

> >>>>I just head my head flowed in stock fashion (High Port). The intake
> numbers
> were far better than the exhaust

Nissans Characteristics is poor exhaust flow. The intake does outflow the
exhaust. I have been tampering with the different combos. On my bench I have
seen between 127 and 130 cfm at 10 inches of water(dependind on air temps).
The stock head seams to stop moving air at 10.5 mm (.413 in) lift. The low
port head flows upto 11.5mm (.452) lift at peak. The low port flows very
similar numbers. The difference between them is that the high port will start
to flow better in the lower lift points. It seams the low port head is always
1 mm lift in air flow slower. The layout curve is pretty much the same just
the high port starts moving air first in the lower lift points.

>>>>>>.5 mm oversized stainless valves
I think over size valves can be a waste of time and money. The amount of
difference they make is almost nothing. Ive seen 3 to 4 cfm change in this. I
think the ratio of the size can make a better difference 1 mm increase in the
exhaust valve can cause a better ratio from intake to exhaust. this can help
the exhaust to move the air out of the head better with keeping the intake a
stock size. I have experienced with this combo. I think this gives a better
low end power to the car. the characteristics of the oversized valves have a
lot to do with the porting done in the ports. I have seen the necks of the
valves trimmed down. This actually lost cfm. these valves were out of the DPR
head. Unusual that he would make you lose air flow. The stepping in the valve
could work because of the fuel hitting it. which can cause the air flow to
change. The injector does point right at the valve. I could not test this.
This is a trick compromise the only way to know is trial and error.

>>>I know everyone raves about DPR, but no one has been able
to provide me with flow numbers and the only before and after dyno numbers I
have found were Mike K's 200 and I wasn't to satisfied with those results.

DPR's head is a nice piece. There can be improvements to the head. As far as
welding the chamber this was done after his head was run. this lost torque in
the lower rpms. Mikes car IM sure was done at a conservative level also.