Nothing to do with potential. THe valve springs/retainers and or lifters are needed for safety for higher revving. If he is going to 7500 stock head is more than fine.

 

i got some numbers on my budy evo on stock turbo i will be downloading soon

 

280s require any gears or anything? Or you just running them like you'd run some 272s?

 

Agreed, there is no potential gain in power from springs/retainers. People ask me frequently about this. Money better spent elsewhere. There is a 600whp local using stock valvetrain+280s. Even to 8500 is doable. I would not do this on a stock turbo as there is little to gain with big boost dropoff, but if you can supply enough air to the motor, it is a benefit to rev that high.

 

You can run them at zero/zero. It is a good setting for 280's. This same local went retarded (as in -neg) on settings and them switched it back to 0/0. I run a staggered retarded setting personally.

 

that's what I'm saying...potential as in rev'n higher, not producing more power....

 

280/280 on stock valvetrain with no gears....AEM EMS

351/330...love em

 

how about a 272/280 combo? Has anybody tried this yet?

 

and ı want to ask how should ı set my 264/272 cam gear setting any idea?

 

What are people using to tune the 280s? Would they run ok on a ECU flash or Utec?

 

Read the thread, this has already been stated.

 

I made right around 350 whp (34X.XX) and a little less torque at 21/18 psi (really jumpy)

 

I would disagree. Several people now, including myself, have found that the optimal setting for HKS 280 cams on their setup is +2/0 (this is on WR/TME/3071 turbos). I initially had the cams set to 0/0 and got weak (slow) spool and less-than-expected power. Changing the cam settings from 0/0 to +2/0 gained 16whp/17tq and improved spoolup by 200 rpm - not too shabby, IMO.

My theory is that the VE of the 4G63 falls off too much past 7000rpms to effectively utilize the longer duration, and advancing the intake cam brings the powerband of the 280s back down to where it can be utilized.

l8r)

 

I have 272in and 280ex and i love em. I pull past my buddy with stright 272 in his rs. Last weekend I made right around 350 whp. With a dynoflash.

 

The +2/0 setting actually increases overlap, but the advance placement of the intake cam allows the overlap to work sooner in the rpm range. What this does is refocus the mechanical efficiency of the engine more toward the midrange as opposed to near the rev limit. This does not seem to hurt peak power, probably due to the long duration of the 280 intake cam.

It's interesting that such a tight LSA (106 deg) works so well in this application, but apparently the exhaust side flows well enough such that reversion isn't a problem. A larger turbine housing and tubular manifold (both of which I'm using) almost certainly enhances the result.