Rb25 rebuild

[Nismo33]

I am looking at putting forgies ect in my rb25. I am runnung a GT30R turbo with intake plenum,injectors all the bolt on's ect and am making about 350rrwhp. Any ideas on where to take it to toughen up the bottom end a bit so I can push the boost up over 20psi., what it would cost and how far should i go? I only have about $6000 to play with.

[TJ]

Any decent performance shop should be able to do it....

Budgest wise perhaps pay someone to remove the motor as labour is going to kill you.

[Miami]

But...the "Chainsaw" only had a stock bottom end, and some Tomei cams and adjustable cam-gear, along with basic bolt-ons, and it was revving to 10 000rpm on its way to winning DA round over the weekend - the commentators told me so :D

Why would anyone ever need to rebuild bottom end of 25s ever again??

[Nemi]

pm me if you want help

[TJ]

Clints 32 has cams, only internal mod.

[SLEEKA]

How much over 20psi do you want to go? how much more power do you want?
forged pistons, forged rods, a nice set a bearings, new studs, new cams, headwork. Thats as far i would go and that should be with in your 6k budjet. The crank should be fine as is...

[Nismo33]

What is PM me?

[Joe]

PM = Private Message

[Jazza]

Psi is just a pressure reading.. ie 25psi on small turbo wouldn't be as hard on the motor as 20psi with a big f**k off turbo.. the amount of air-flow your puttin through the motor with that sized turbo and where the efficency of the turbo is @ what pressure readings is what you need to look at.

What boost do you currently run and any workshop (ie x-speed SOR or hyperdrive NOR etc) will be able to help you if your serious. As mentioned above labour costs for removing the engine etc are killer

[zeroyon]

if you just want to run 20 psi. Then all i would do is put in a Metal head gasket and drop the comp ratio slightly. Be much cheaper and easier to get done then forgies.

Stock rb25 bottom end will handle 20 psi no problems if the compression ratio is right.

Turbo PSI doesn't kill engines its cyclinder pressures and pinging that does.

[Nismo33]

currently running about 15-16 psi. Will pushing it over 20 screw my motor?

[Cake]

if you just want to run 20 psi. Then all i would do is put in a Metal head gasket and drop the comp ratio slightly. Be much cheaper and easier to get done then forgies.

Stock rb25 bottom end will handle 20 psi no problems if the compression ratio is right.

Turbo PSI doesn't kill engines its cyclinder pressures and pinging that does.

100% Agreed. Unless you are after some very serious power, I would just slide a thicker metal head gasket in there, and drop some decent cams in while you're at it. A few guys over east have been running this sort of combo (around 400rwhp) and still going strong after a couple of years. I've found that in Perth, building a motor can be more trouble than it's worth, especially if you aren't chasing a few hundred extra HP.

[TJ]

Especially in Rb25 powered R33's!

[Jazza]

Stock rb25 bottom end will handle 20 psi no problems if the compression ratio is right.

Turbo PSI doesn't kill engines its cyclinder pressures and pinging that does.

If you just turn up to 20psi, it'll prob have too much ign timing in it for that boost and ping its nuts off! But if you have it tuned for 20psi you won't screw your motor straight away but it's obvious more stress on the motor in the long run, think about the head gasket idea dude...

[HotSil80]

You won't get much life out off it if you start pushing such high psi.

[Lumpy]

I wouldnt even bother fitting the metal gasket unless you really think you need it, and then while youre there you may as well fit studs, but then where does the line get drawn?
There's a lot to be said for keeping em std. Chainsaw is stock internally other than having tomei's sticks in. The reason it survives has more to do with the ancillary equipment selection and tune.
While on the topic of building engines, I am selling an RB Hi-Energy Circuit eliminator sump (gets oil capacity over 7 litres) and Ross Metal Jacket top spec dampener. Used for less than 20 hours, including sleep. Was on Borneo's car but we went dry sump.

[caibs]

get the block o-ringed while its apart, arp studs, forgies and a balance and it should be quite strong safe and reliable providing it has a good tune.