EFFECTS OF N/A RACE CAM ON TURBO SETUP

[ADAM]

HOW WOULD A HIGH LIFT CAM (OVER 500) EFFECT THE PERFORMANCE OF A TURBOCHARGED SET UP....

2 TRAINS OF THOUGHT

1=IT WILL HURT PERFORMANCE BY ALLOWING TO MUCH COOL AIR TO BLOW THROUGH THE ENGINE DUE TO THE VALVE OVERLAP AND DURATION.

2=IT WILL HELP PERFORMANCE SINCE THE CAM IS DESIGNED FOR 5k+ RPM OPERATION ANYWAY, AND THE HEAT PRODUCED WILL BE ENOUGH TO SPOOL THE TURBO FAST IN ANY CASE.

[Shaman]

It's a mistake not to match the cam/s carefully to the application. The right amount of overlap is crucial to success with forced induction.

You may, for example, find that you have a major pinging problem that you can't sort out. With FI, the trick is getting the spent air out as fast as possible, air coming in is being forced.

[ADAM]

WELL THE CAM GETS THE AIR OUT FINE...TOO GOOD....thats what i think the problem may be....it drawing boost right thru the engine thus cooling the exhaust charge down.....as for pinging that is not a concern as compression is low 9:1 and boost will be low...7-9psi, and fuel will be high octane 100-104...plus i have a retard control if things get out of hand, and need to make small timing changes..

i guess i will see...in any case it will make more power...i just want to maximise it..

[Shaman]

In that case, run more boost and see what happens. :)

Seriously, the heat of the charge is not as important to the turbo as the volume. Heat != good.

[ADAM]

yeah..but the volume is related to the heat (hot air takes up more space) thats how the turbine in the turbo works...it is a heat scavenger

my motor can only handle 10psi with stock pistons...as the piston lands are the weak point..in my motor with 7-9psi it should be making 250-280bhp...at least thats what some other people have gooten with thier cars..

mabey the cam at high revs will actually produce more power?

will have to wait for the dyno....

and if turbonetics would ship me my dam wastegate..i could get on with the install :)

[JAMIE EASTMAN]

On dodge 2.2Turbo engines the 2.5 naturally asperated cam is the best one because it stays open a bit longer to let in that .3of a liter, sometimes the N/A cam will work fine. What are the specs of your cam?

[B18C5]

Doesn't the back pressure from driving the turbo prevent blow by? I know when people started making superchargers for cammy Honda VTEC motors they couldn't make any power (they still don't). There are no problems with turbos. Some turbo guys even use Type R cams instead of the ones they came with, although I haven't heard of anyone using any really wild aftermarket cams yet.

[JAMIE EASTMAN]

I think there are too many variables to guess how the cams work with his set up.
turbine housing size,exhaust caracterists,valve size,exhaust temps,Igot lucky
because my Mopar manuals have all the info I need from the daytonas and lebarons
from the IMSA days. I cant wait to see how his car works out.

PS dont forget the hardened exhaust valves.

[ADAM]

the turbo does have backpressure but that is overcome buy the boost that is created...this is how it works....

a n/a race cam is designed to suck as much air into the chamber as possible....to do that that the intake and exhaust are opening in such a way that it helps the vacuum...however when boost is added, the boost actually can blow thru the head blowing cool boosted air into the turbine...which is bad.....

now how much cool air will blow thru?
will it matter at high rpm 5k+ ?

i personally think that it will increase hp at high rpm, as so much flow is happening anyway, the wastegate must dump it. since this is not a daily driver who cares what happens off throttle or low rpm.

re: valves...have stock valves, so we will see how they react to the heat :)
re: cam specs...i have them somewhere..suffice to say it is a full out race cam

in all the other kits that i have seen the 240sx can handle max 10psi...before bad things happen. and at 7-8psi i will be making near 300hp...which is enough to deal with those pesky talons and type r's and miata's


jamie...we will have to do some 1/4 miles runs at sahhinville this season :)