aftermarket cams???

[bigcarl]

in the process of rebuilding my rb25, the rebuild is costing me $6800 including engine out / in and tuning. this hasnt left me much change for aftermarket cams. my question is would an adjustable exhaust cam wheel on its own give much of a gain? im dropping cr from 9 to 1 to 8.5 to 1 so i can run more boost. at the moment im running gt30 500hp turbo with usual bolt on mods to get a power figure of 229 rwkws at 13psi and 260rwkws at 20psi. what sought of gains could i expect screwing in more boost say 22 to 24 psi with the 8.5 to 1 compression? exhaust cam wheel? what setting? any thoughts an ideas would be good?

[Trust33]

Did your rebuild include forgies?

Go to one of the sites that have an estimator.If u know the specs of your engine i dont see why it wouldnt give a close enough figure.

[R31Nismoid]

where is it going for the rebuild?

Im still using my stock head

[bigcarl]

yes , ive got gtr rods and wisieco forged pistons 20 thou over. tim sheather at electronic automotive epping is building it. where are these sites located?

[R31Nismoid]

i think im still running the normal comp on my car also...

hrm.

nengun proably the best. if you really wanna get the CAMS...

[bigcarl]

i think $880 delivered for 10 rwkws is probably a waste of time. mine will be running 8.5 or 8.7 to 1 because im running 20 psi of boost and will probably run more . do you think 22 psi on high boost will give me the extra 10 or so rwkws nismoid?

[SLY33]

i realise that theres not much $ left for cams, but since your going the whole hog, full rebuild, id just wait a little longer till you can add cams to it, that way your saving on tuning in the future --> because you WILL want them later! Personally i wouldnt bother with the cam gear but thats just me! my HKS exhaust cam gear is still sitting on the shelf after about 2 years, now that im getting some poncams i wont even need it...

[SLY33]

i think $880 delivered for 10 rwkws is probably a waste of time. mine will be running 8.5 or 8.7 to 1 because im running 20 psi of boost and will probably run more . do you think 22 psi on high boost will give me the extra 10 or so rwkws nismoid?

If you think that cams will only give you 10rwkws peak then you are not realising their full benefit! Its the midrange increase which can be substantial as well as some increase in spool up time. This means more engine flexibility (ie drivability) Also depending on the cams you will lower the dynamic compression so you can run more boost with the std 9:1 CR, keeping a nice crisp off boost response.

[R31Nismoid]

a couple psi will get you 10rwkw is the turbo isnt off its scale.

but ive found mine likes anything over 20psi, it just scoots along. 17psi feels lazy!

That why i havent done cams yet, money is better spend elsewhere for better gain and that sorta thing. i might play around with cams later on this year or the next.

I really need to scan my dyno charts

[bigcarl]

yes id love to see those dyno sheets nismoid . does anyone know at what revs im i would be doing in 4th gear at 170klm/h because that is when my power dives off??

[SLK-GTR]

my mate has australia's fastest RB25 street car and he is still running standard cams but he is running an adjustable exhaust cam wheel not sure what setting is is set at but the wheel made an extra 30-35 rwkws now he is making 400rwkw. breciani did all the work on it im sure if u call him he will give the low down.

[R31Nismoid]

CAMS gears on the 25 head would have done nothing for me, hence we aint using them

good gain on an RB26 though good power to be made with one.

my power starts to die off around 180km/h the a bit more (10-14kw) to 195km/h where i assume the limiter is (7800-7900rpm)