hack77

I am building a b18b
I am Planning on running crower 62404s on roughly 10 punds of boost
from what i have read as long as you set the cams up so thier is as little over lap as possible it should make good low and high end power.
I am just wondering if anyone who has done this has any tips or if thier is anything i should look out for that might get over looked in my reserch ?

LightningTeg

Not touching the cam timing I've made good power on them (370whp @ 15psi). Id like to fool around sometime though and do as you've said

hack77

Ya I know allot of people run them like you do, witch I have considered for the rough idle. What I cant seem to find is how mutch of a horspower difference it makes if you set them up with out overlap.

blackeg

I wouldn't be suprised if you see gains of 10 to 20 hp just from messing with the cam timing

nealnanoHX

I personally would go with 402s as they seem to be a good trade off in low end vs top end power. 404s rip in the top end but need a valve train that can handle them and the needed revs to 9k to see all the power the 404s can offer. With boost you can over come the low end. Really I would just put the money into a Vtec head swap with some GSR or CTR cams, this setup does really nice under boost. My tuner runs a B16 sleeved and built block, Endyn worked GSR head with GSR cams on a standard TO4E .57 .63 AR Garret making 380whp on only 11-12psi.

hack77

Realy because i was under the imperssion that with the cam timming adjusted so that thier is not alot of over lap the 404s would produce more low end tourqu than the 402s? a

blackeg

run the bigger cam, a little extra overlap will help with scavenging

nealnanoHX

There are others on here that know more on this for sure so please help out. Be sure to upgrade valve train for those cams and check PTV clearance if doing a big over lap. Turbos will respond well to the correct cam timing and over lap.

LocoJoe

Isnt scavenging looked for in NA builds? Boost is pressurized so no need to scavenge or thats what I thought. Isnt making more overlap just wasting the boost? I've seen more overlap yield negative results.

nealnanoHX

I did not say to have a lot of over lap only to have the correct over lap. Turbos do best with less over lap because it allows more exhaust gas to go to the turbo each time the exhaust valves open. The more efficiently you can get the exhaust gases out of the motor and to the turbo the better it will perform. Stock Ls cams are hardly a week spot when building a LS turbo, not saying they are the bests cams but you can make power with them, I have seem 318whp with stock Ls cams and head. The P75 is really the week point due to poor flow, having the exhaust ports reworked to flow better will see good gains for a turbo set up. This is why I went to a Vtec head before boosting, I could have done a turbo for the cost of the Vtec head swap but I wanted my motor to be as efficient as possible before boosting. 10 pis on a Vtec head will make more than 10psi with a Ls head.