egVTI

he my tuner said my n/a toda cams are causing my mega flat spot in the mid range. this in on a b16 , he said n/a cams have high lift and long duration n o a boosted set up you want high lift but a short durtation
so was looking a doing the head completely wot you thinks of this -

skunk2 turbo cams stage 2
skunk2 pro series intake
skunk2 70mm T/B
skunk2 valvesprings
skunk2 retainers

anyone used the turbo cams from skunk2? stage 1 or 2?
any other reccomendations ?

aint got a scanner here the now but the graph kinda goes like this
3k -105lbs
3.5k -112lbs
4k -128lbs
4.5k -130lbs
5k -139lbs
5.5k -137lbs
6k -126lbs
6.5k -129lbs
7k -141lbs
7.5k -152lbs
8k -155lbs
8.5k -162lbs

all the torque fig thru rev range

its b16 stock internals ,drag gen 3 kit @7psi with toda cams


thanks for any help you guys give

Ravage70

i will be running the NA stage 2s
play with the gears and timing and you should see gains

z1guy

i think your tuner was LAZY. n/a cams are fine on a boosted motor. find something that favors the exhaust (sohc guy so i dont know dohc specs) and you will be better off as well. i bet he could have added a little more timing to the midrange to get rid of that dip anyways. whats the HP look like

egVTI

240hp @ 7psi

beerbongskickass

You want ITR/CTR or GSR cams. These threads have some good info.

http://forums.evans-tuning.com/viewtopic.php?t=1623
http://forums.evans-tuning.com/viewtopic.php?t=2341
http://forums.evans-tuning.com/viewtopic.php?t=1744

darksol2005

ur tuner was right about not wanting the longer duration, but i couldn't give you an answer as to wether or not that's whats causing a flat spot. could be, but also couldn't be

kablammyman

Agreed. Let me see if I can explain this in a few words correctly....

Ummm. When you have that over lap, both sets of valves are open (intake and exhaust). This is good on a N/A motor for that scavenging effect to get exhaust gases out of the motor so fresh air can mix with fuel and combust. However, a boosted motor has air being forced in at a high rate/pressure, so boost goes in and out of the engine before its used. Therefore, over lap isn’t best for boost.

Well, thast what my memory tells me...its been a while since I did any research on the subject. I suspect that a good tuner can use the high lift cams in a good way...somehow...

z1guy

this is all true, but w/ adjustable cam gears you can make up for the valve overlap easily, and use it to your advantage. higher lift is obviously better when boosted where low end tq isnt the main concern, point is, any cam design "n/a, nitrous, or boost" will make more power than stock on a boosted motor. but too much of anything can also be bad. a turbo cam can sometimes move the powerband so high that times will drop because the motor drops out of the powerband when shifting, the dyno will never show this though.

Tom-Guy

What a load of crap. Overlap is desireable for high revving small displacement turbo engines, period. Compare intake to exhaust pressure sometime... it's blowers that don't like overlap. :1

To the original poster: You are running a ****** 7 psi. It is impossibly to make any worthwhile amount of power from a B16 off of a ****** 7 psi, regardless of how many millions of dollars you spend on camshafts. Turn the boost up, rev to 9K, and prepare to be very happy with your NA cams in the 350+ whp range.

z1guy

too much overlap is going to let pressurized air fuel mixture escape through the exhaust period.