Jump to content
SAU Community

Recommended Posts

Hey all, been meaning to ask for a while but kept forgetting.

I have a fair idea of cams but not entirely the effect of them according to their lift / degree's.

Ok, so my understanding is that cams have lift, and I assume that this relates to how high the cam goes when rotating. However, I dont know what the degree's mean or how any of this gives different power gains at different RPM... Engine internals are certainly not my strong point.

Thanks

C

Link to comment
https://www.sau.com.au/forums/topic/123200-cams/
Share on other sites

depends on the setup.

usually more lift = more flow, but you also need duration. the problem lies in getting a good combo as at high rpm you can get valve slap, eg over revving. to compensate you can use tougher valve springs etc. but it depends on the lift. if the lift is more than the springs can take the springs will bind, or over compress.. VERY bad.

if you need high revs eg nat asperated, you need less duration more lift... to raise the rev range

use as a guide as this may not be correct to some out there ;)

Edited by bogcock
Link to comment
https://www.sau.com.au/forums/topic/123200-cams/#findComment-2275388
Share on other sites

So for an internally-stock GTR, you wouldn't want much lift, is that right? I think the tomei poncams are 262 and 10.2 and are supposed to be good for stock engines with bolt ons.

Thanks for this info too.

Link to comment
https://www.sau.com.au/forums/topic/123200-cams/#findComment-2275394
Share on other sites

poncams are good because they use the stock valvetrain.

if you want big power you will need more lift and around 264 duration..

procams are better, but you need to change valve springs, retainers etc

for a stock gtr (internally) cams wont really give too much benifit. ive seen stock cammed gtrs running 600hp with no problems. attend to other parts 1st, such as turbos, ecu, injectors zorst etc

Edited by bogcock
Link to comment
https://www.sau.com.au/forums/topic/123200-cams/#findComment-2275428
Share on other sites

Christian - i went for std turbos, tomei poncams 260 9.15mm.

It made a huge difference to the midrange and drivability.

Someone else on here also did poncams on std turbos...

Full list is:

1.1 bar

turbo back exh

stock airbox, high flow filter

poncams + adj wheels

i reckon area under the curve is pretty good, and low down power...

Dyno_220305.jpg

sure turbos would have made more power, but drivability is very much improved... and I don't drive b/w 5000 - 8000 rpm all the time - 85% if the time is between 2000 and 4000 rpm

don't completely discount cams ;)

Link to comment
https://www.sau.com.au/forums/topic/123200-cams/#findComment-2275514
Share on other sites

Yeah between my 2 GTRs I have done mods quite differently but gotten similar power, but the power is very different.

Old GTR;

Power FC

Full Exhaust

More Boost

243rwkw

New GTR;

Cam Gears

FPR

Full Exhaust

More Boost

250rwkw

But the way that power is produced on the new GTR is astounding compared to the old one and I reckon its all cam gears.

Poncams are only $850-ish delivered from Nengun, not sure how much fitting is tho.

Link to comment
https://www.sau.com.au/forums/topic/123200-cams/#findComment-2275909
Share on other sites

Bit OT - but whats the diff between a PonCam and a ProCam ?

Hi B-Man

I have just been doing similar research on cams also, and have found that while all the specs seem similar on the poncams and low end procams (eg 9.15 lift, similar durations), the procams are apparently a more aggressive "ramp" affecting the speed of valve opening. This means that the procams need the uprated springs where the poncams dont, and presumably affects the power/torque delivery.

The Tomei website has some good info in Engrish describing the cams.

Cheers

Ned

Link to comment
https://www.sau.com.au/forums/topic/123200-cams/#findComment-2275926
Share on other sites

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

    • As far as I can tell I have everything properly set in the Haltech software for engine size, injector data, all sensors seem to be reporting proper numbers.  If I change any injector details it doesnt run right.    Changing the base map is having the biggest change in response, im not sure how people are saying it doesnt really matter.  I'm guessing under normal conditions the ECU is able to self adjust and keep everything smooth.   Right now my best performance is happening by lowering the base map just enough to where the ECU us doing short term cut of about 45% to reach the target Lambda of 14.7.  That way when I start putting load on it still has high enough fuel map to not be so lean.  After 2500 rpm I raised the base map to what would be really rich at no load, but still helps with the lean spots on load.  I figure I don't have much reason to be above 2500rpm with no load.  When watching other videos it seems their target is reached much faster than mine.  Mine takes forever to adjust and reach the target. My next few days will be spent making sure timing is good, it was running fine before doing the ECU and DBW swap, but want to verify.  I'll also probably swap in the new injectors I bought as well as a walbro 255 pump.  
    • It would be different if the sealant hadn't started to peel up with gaps in the glue about ~6cm and bigger in some areas. I would much prefer not having to do the work take them off the car . However, the filler the owner put in the roof rack mount cavities has shrunk and begun to crack on the rail delete panels. I cant trust that to hold off moisture ingress especially where I live. Not only that but I have faded paint on as well as on either side of these panels, so they would need to come off to give the roofline a proper respray. My goal is to get in there and put a healthy amount of epoxy instead of panel filler/bog and potentially skin with carbon fiber. I have 2 spare rolls from an old motorcycle fairing project from a few years back and I think it'd be a nice touch on a black stag.  I've seen some threads where people replace their roof rack delete with a welded in sheet metal part. But has anyone re-worked the roof rails themselves? It seems like there is a lot of volume there to add in some threads and maybe a keyway for a quick(er) release roof rack system. Not afraid to mill something out if I have to. It would be cool to have a cross bar only setup. That way I can keep the sleek roofline that would accept a couple bolts to gain back that extra utility  3D print some snazzy covers to hide the threaded section to be thorough and keep things covered when not using the rack. 
    • Probably not. A workshop grade scantool is my go to for proper Consult interrogation. Any workshop grade tool should do it. Just go to a workshop.
    • In my head it does make sense to be a fuel problem since that is what I touched when cleaning the system. When I was testing with the fuel pressure gauge, the pressure was constantly 2.5 bar with the FPR vacuum removed. When stalling, the pressure was going up to 3.0 bar (which is how it should be on ignition).
    • ECUtalk pages don't mention they support the ABS computer (consult port has more than one CAN), so you might just need a different scan tool. But, I would expect ABS is a different light to the brake warning/handbrake light, do you see an ABS light come on for a few seconds when you turn the key from ACC to IGN? But since you said: I'd have a look at the ABS sensors in the rear hubs to make sure they are not damaged, disconnected etc.
×
×
  • Create New...