Jump to content
SAU Community

Camshafts


Recommended Posts

Guest Nismo_Freak

What kind of gains are seen from a bump in duration and lift?

RB26DETT

Say using the 272 duration / 10.5mm lift, w/ valve springs on a fairly standard motor using only intake, 12 psi boost, full turbo back exhaust, fmic, and a HKS AVC (the fuel controller).

I would also swap the cam gears for adjustables and go with a 4 degree retard on the exhaust with a 1 degree advance on the intake.

Assuming fuel was optimized for the added airflow and tuned properly.

Link to comment
https://www.sau.com.au/forums/topic/10527-camshafts/
Share on other sites

The gains are huge, it will be one of the most important factors in getting huge horsepower. Without decent cams then the potential of any turbo is not used. I would only tend to use cams like that with a bigger turbo, but even without it a 10-15% increase in power is possible.

See'ya:burnout:

Link to comment
https://www.sau.com.au/forums/topic/10527-camshafts/#findComment-168818
Share on other sites

Guest Nismo_Freak

Sounds about right I suppose... the camshafts only increase the efficiency of the motor at the higher revolutions with a slight drop at lower rpms. This in turn creates lag as noted. But the end result is more power produced at lower boost levels. The requirement for octane however goes up because the dynamic compression increases, the same when boosting more. I just needed some numbers to go by. The stock cams are as follows, I believe:

Intake: 240 duration w/ .338 lift (8.58mm)

Exhaust: 236 duration w/ .326 lift (8.28mm)

The use of the cam gears will allow me to maintain the midrange and gain back some of the boost threashold lost when I moved to the hotter cams.

Link to comment
https://www.sau.com.au/forums/topic/10527-camshafts/#findComment-170233
Share on other sites

The 272's will kick in at around 4000+rpm and give the motor more legs to 8000+rpm. Something around 250 or so duration would be a better choice for a streeter. I think there are a few around 254 duration.

Most aftermaket cams need to 'dialed in' according to the motor. The factory usually designs them for a 0 deg fit but, depending on what you have done they may benifit with various timing settings.ie: don't take 4 degrees as gospel if you use non factory cams.

Link to comment
https://www.sau.com.au/forums/topic/10527-camshafts/#findComment-170393
Share on other sites

  • 2 weeks later...

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • just an update to this, poor man pays twice  Tried sanding down the pulleys but it didnt do the trick. Chucked another second hand alternator in the na car which I got for free off my mate and its fixed the squelling. Must have been unlucky with the bearings.    As for my turbo car, I managed to pick up a cwc rb alternator conversion bracket + LS alternator for 250 off marketplace, looked to be in really good nick. Installed it , started the car and its not charging the battery.... ( Im not good with auto elec stuff so im not sure if this was all I needed to do but I verified such by using a multimeter on the battery when the engine was running and I was only getting 12.2v )   I had to modify the earth strap for the new LS alternator , factory earth strap was a 10mm bolt which did not fit the bolt on the LS alternator which was double the size so I cut it off , went to repco bought some ring terminals that fit, crimped it onto the old earth strap and bolted it up to the alternator , started the car and same issue. Ran like shit and was reading 12.2 at the battery.  For a "plug and play" advertised kit thats not very plug and play but alas.  My question is , am I missing something ? Ive been reading that some people recommend upgrading the stock 80 amp alternator fuse to a 140 amp but I dont see how that would stop the alternator charging especially at idle not under load.  Regardless ive pulled it out and am going to get it bench tested by an auto elec tomorrow but it would be handy to know if ive missed something silly or have done something wrong.   
    • My wild guess is that you have popped off an intake pipe....check all of the hoses between the turbo and the throttle for splits or loose clamps.
    • Awesome, thanks for sharing!
    • To provide more specific help, more information is needed. What Android screen? What is its wiring diagram? Does the car's wiring have power at any required BAT and ACC wires, and is the loom's earth good?
    • So, now all you need to do is connect the 2 or 3x 12v feeds into the unit to permanent 12v, ACC 12V and IGN 12V that you can find in the spot behind the stereo, and the earth, and then it will switch on with the car.
×
×
  • Create New...