Poncams On A Highly Modified Rb25? Gains?

[ReganGTS25T]

ive got a 409 rwkw rb25det on stock cams with a gt3582 at 2 bar built cp pistons tomei rods greddy intake manifold its also port n polished how much would i gain with some poncams havent found any information on the search engine soo i guess i have to ask heh its either that or n2o i wouldlike the cams but just dont know how much those crapy 256 8.9 lift cams will give me

[RB30-POWER]

got to be honest, that is massive power mate, can't be on pump fuel?

i would be looking bigger then the 256 type deals.

the biggest advantage should be the way the car drives, instead of the standard cams falling over (may not feel like it), bigger cams would extend the power band where you want it, which is high rpm with a turbo that size on the 2.5l engine.

from higher power band will come higher power since it's basically a derivative of torque vs rpm, make torque at higher rpm and more power is the result, bearing in mind turbine back pressure, that also increases with rpm, depending on how much you are pushing it.

just remember rod loads go up rather fast as soon as you extend the power band by any significant amount and will have a greater chance of breakages. also keep in mind the hydraulic lifters, if it was a neo head with solid lifters, you would only need to worry about the bottom end.

in saying that 8000rpm still keeps the piston speed just under 4000ft/min and lifters should be ok at that rpm.

as always cams will detract from low rpm drivability if you go too big, just depends on what the purpose is meant to be.

if you only want more power for dyno days, just get a bigger turbo, if you want to track it, big cams might be the better alternative, if it's a street car a mild cam upgrade might be best with a nos system as an extra.

never an exact science, mostly trail and error, which can be a reason to copy other peoples successful results if you can obtain them.

Edited December 25, 2008 by RB30-POWER

[ReganGTS25T]

got to be honest, that is massive power mate, can't be on pump fuel?

i would be looking bigger then the 256 type deals.

the biggest advantage should be the way the car drives, instead of the standard cams falling over (may not feel like it), bigger cams would extend the power band where you want it, which is high rpm with a turbo that size on the 2.5l engine.

from higher power band will come higher power since it's basically a derivative of torque vs rpm, make torque at higher rpm and more power is the result, bearing in mind turbine back pressure also that increases with rpm, depending on how much you are pushing it.

just remember rod loads go rather fast as soon as you extend the power band by any significant amount and will have a greater chance of breakages. also keep in mind the hydraulic lifters, if it was a neo head with solid lifters, you would only need to worry about the bottom end.

in saying that 8000rpm still keeps the piston speed just under 4000ft/min and lifters should be ok at that rpm.

as always cams will detract from low rpm drivability if you go too big, just depends on what the purpose is meant to be.

if you only want more power for dyno days, just get a bigger turbo, if you want to track it, big cams might be the better alternative, if it's a street car a mild cam upgrade might be best with a nos system as an extra.

never an exact science, mostly trail and error, which can be a reason to copy other peoples successful results if you can obtain them.

i do run those numbers on pump gas actualy but with meth injection, ive ran 11.1 ona full weight car with a 165 kilo driver(im heavy) on unpreped runway with a portable 1/4 mile timing system, its my daily driver though and i want more power but id be using vp race fuels i need to gain about 110 more kw's at the fly i really want to run a mid 10 this febuary just looking at my options i guess im goin to go with gas and 2.5 bar on the gt3582

[NYTSKY]

The biggest gains i found was off boost driving. Not much throttle was needed to get around town, more torque everywhere.

But in you situation once boosts hits you will feel little difference if any.

I would go 260-270 something.

[WARLORD]

apexi do a 270 in and out

[NYTSKY]

i do run those numbers on pump gas actualy but with meth injection, ive ran 11.1 ona full weight car with a 165 kilo driver(im heavy) on unpreped runway with a portable 1/4 mile timing system, its my daily driver though and i want more power but id be using vp race fuels i need to gain about 110 more kw's at the fly i really want to run a mid 10 this febuary just looking at my options i guess im goin to go with gas and 2.5 bar on the gt3582

Get it tuned in E85!

[Bliksem]

HKS do 264

[The Mafia]

I'm pretty sure that the GT3582 is at it absolute peak anyway, and won't be able to make any more power.

You'll find if you upgrade your cams, you're increasing flow in the head, but the turbo won't be able to keep up anymore.

So to get the gain that you want, you'll need to upgrade cams and the turbo. Get a T04Z, or something a bit bigger?

[ReganGTS25T]

I'm pretty sure that the GT3582 is at it absolute peak anyway, and won't be able to make any more power.

You'll find if you upgrade your cams, you're increasing flow in the head, but the turbo won't be able to keep up anymore.

So to get the gain that you want, you'll need to upgrade cams and the turbo. Get a T04Z, or something a bit bigger?

tell me how the ams evo's in the states do 600-650awhp with a gt3582r? on a smaller engine im pretty sure the gt3582r can get to 700 crank horsepower on my rb25

[ReganGTS25T]

oh and would those 270 or 264 cams work with hydro lifters im guessing id still need springs

[NYTSKY]

oh and would those 270 or 264 cams work with hydro lifters im guessing id still need springs

Definitely need valve springs.

[PM-R33]

For 270 degree cams your usually looking at 10mm lift or more, for that you'll definetely need to go solid lifters. However im pretty sure you can get HKS step one cams in 272 with only 8.7mm lift. For the amount of power your pushing, you'd be stupid not to go solid lifters with some big cams if drag racing is what you want the car for with that turbo.

[bradsm87]

dude for that setup, u should be putting in at least procam 260/260 10.8mm. I'm surprised that turbo even spools up with the stock cams!

[ReganGTS25T]

eh i got 2 bar at 4200 rpms im red lining 8k the problem is that inbetween solid lifters springs cams and gears its like 2500 usd its a big chunk of change, and its my daily driver i dont want to go with very extreme cams either

Edited December 26, 2008 by ReganGTS25T

[zebra]

dude for that setup, u should be putting in at least procam 260/260 10.8mm. I'm surprised that turbo even spools up with the stock cams!

lolwut

[bradsm87]

eh i got 2 bar at 4200 rpms im red lining 8k the problem is that inbetween solid lifters springs cams and gears its like 2500 usd its a big chunk of change, and its my daily driver i dont want to go with very extreme cams either

Go hks 264's then mate. They'll drop straight in. U should be able to make the same power on 1.5 bar with them which is more in the efficiency range of the turbo. Should hit a lot harder in the midrange too.

Edited December 26, 2008 by bradsm87

[ReganGTS25T]

you guys got me all worried now that the cams arent goin to give me crap power cause of the lifters , i mightmjust go for the laughing gas

[bradsm87]

Who said anything about lifters being a problem? Cams are one of the first upgrades that should be considered. Usually long before rebuilds, porting and way before n2o. Just stick in some hks step 1 264 cams and you're done. Don't worry about gears or anything. That along with turning boost down to about 1.7 to get it into the turbo's more efficient range should giv u a lot more midrange and more power too.

[shanef]

i wouldnt really call it 'highly modified' if the heads pretty much stock

to see any reasonable gains its a head off job and convert to solid lifters and oversize valves

or for a better way to go, buy dirtgarage's built rb26 head for 3800 and save urself about 3k

P.S what mph was that 11.1 run at?

[ReganGTS25T]

i wouldnt really call it 'highly modified' if the heads pretty much stock

to see any reasonable gains its a head off job and convert to solid lifters.

or for a better way to go, buy dirtgarage's built rb26 head for 3800 and save urself about 3k

P.S what mph was that 11.1 run at?

can i just bolt on an rb26 head to my rb25 block? it was at 132 mph eh well compared to most rb25's on this forum its pretty well modified atleast brought to the limits of some parts